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| -rw-r--r-- | ext/fts3/fts3.c | 6116 |
1 files changed, 6116 insertions, 0 deletions
diff --git a/ext/fts3/fts3.c b/ext/fts3/fts3.c new file mode 100644 index 0000000..c43eac4 --- /dev/null +++ b/ext/fts3/fts3.c @@ -0,0 +1,6116 @@ +/* +** 2006 Oct 10 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +****************************************************************************** +** +** This is an SQLite module implementing full-text search. +*/ + +/* +** The code in this file is only compiled if: +** +** * The FTS3 module is being built as an extension +** (in which case SQLITE_CORE is not defined), or +** +** * The FTS3 module is being built into the core of +** SQLite (in which case SQLITE_ENABLE_FTS3 is defined). +*/ + +/* The full-text index is stored in a series of b+tree (-like) +** structures called segments which map terms to doclists. The +** structures are like b+trees in layout, but are constructed from the +** bottom up in optimal fashion and are not updatable. Since trees +** are built from the bottom up, things will be described from the +** bottom up. +** +** +**** Varints **** +** The basic unit of encoding is a variable-length integer called a +** varint. We encode variable-length integers in little-endian order +** using seven bits * per byte as follows: +** +** KEY: +** A = 0xxxxxxx 7 bits of data and one flag bit +** B = 1xxxxxxx 7 bits of data and one flag bit +** +** 7 bits - A +** 14 bits - BA +** 21 bits - BBA +** and so on. +** +** This is similar in concept to how sqlite encodes "varints" but +** the encoding is not the same. SQLite varints are big-endian +** are are limited to 9 bytes in length whereas FTS3 varints are +** little-endian and can be up to 10 bytes in length (in theory). +** +** Example encodings: +** +** 1: 0x01 +** 127: 0x7f +** 128: 0x81 0x00 +** +** +**** Document lists **** +** A doclist (document list) holds a docid-sorted list of hits for a +** given term. Doclists hold docids and associated token positions. +** A docid is the unique integer identifier for a single document. +** A position is the index of a word within the document. The first +** word of the document has a position of 0. +** +** FTS3 used to optionally store character offsets using a compile-time +** option. But that functionality is no longer supported. +** +** A doclist is stored like this: +** +** array { +** varint docid; (delta from previous doclist) +** array { (position list for column 0) +** varint position; (2 more than the delta from previous position) +** } +** array { +** varint POS_COLUMN; (marks start of position list for new column) +** varint column; (index of new column) +** array { +** varint position; (2 more than the delta from previous position) +** } +** } +** varint POS_END; (marks end of positions for this document. +** } +** +** Here, array { X } means zero or more occurrences of X, adjacent in +** memory. A "position" is an index of a token in the token stream +** generated by the tokenizer. Note that POS_END and POS_COLUMN occur +** in the same logical place as the position element, and act as sentinals +** ending a position list array. POS_END is 0. POS_COLUMN is 1. +** The positions numbers are not stored literally but rather as two more +** than the difference from the prior position, or the just the position plus +** 2 for the first position. Example: +** +** label: A B C D E F G H I J K +** value: 123 5 9 1 1 14 35 0 234 72 0 +** +** The 123 value is the first docid. For column zero in this document +** there are two matches at positions 3 and 10 (5-2 and 9-2+3). The 1 +** at D signals the start of a new column; the 1 at E indicates that the +** new column is column number 1. There are two positions at 12 and 45 +** (14-2 and 35-2+12). The 0 at H indicate the end-of-document. The +** 234 at I is the delta to next docid (357). It has one position 70 +** (72-2) and then terminates with the 0 at K. +** +** A "position-list" is the list of positions for multiple columns for +** a single docid. A "column-list" is the set of positions for a single +** column. Hence, a position-list consists of one or more column-lists, +** a document record consists of a docid followed by a position-list and +** a doclist consists of one or more document records. +** +** A bare doclist omits the position information, becoming an +** array of varint-encoded docids. +** +**** Segment leaf nodes **** +** Segment leaf nodes store terms and doclists, ordered by term. Leaf +** nodes are written using LeafWriter, and read using LeafReader (to +** iterate through a single leaf node's data) and LeavesReader (to +** iterate through a segment's entire leaf layer). Leaf nodes have +** the format: +** +** varint iHeight; (height from leaf level, always 0) +** varint nTerm; (length of first term) +** char pTerm[nTerm]; (content of first term) +** varint nDoclist; (length of term's associated doclist) +** char pDoclist[nDoclist]; (content of doclist) +** array { +** (further terms are delta-encoded) +** varint nPrefix; (length of prefix shared with previous term) +** varint nSuffix; (length of unshared suffix) +** char pTermSuffix[nSuffix];(unshared suffix of next term) +** varint nDoclist; (length of term's associated doclist) +** char pDoclist[nDoclist]; (content of doclist) +** } +** +** Here, array { X } means zero or more occurrences of X, adjacent in +** memory. +** +** Leaf nodes are broken into blocks which are stored contiguously in +** the %_segments table in sorted order. This means that when the end +** of a node is reached, the next term is in the node with the next +** greater node id. +** +** New data is spilled to a new leaf node when the current node +** exceeds LEAF_MAX bytes (default 2048). New data which itself is +** larger than STANDALONE_MIN (default 1024) is placed in a standalone +** node (a leaf node with a single term and doclist). The goal of +** these settings is to pack together groups of small doclists while +** making it efficient to directly access large doclists. The +** assumption is that large doclists represent terms which are more +** likely to be query targets. +** +** TODO(shess) It may be useful for blocking decisions to be more +** dynamic. For instance, it may make more sense to have a 2.5k leaf +** node rather than splitting into 2k and .5k nodes. My intuition is +** that this might extend through 2x or 4x the pagesize. +** +** +**** Segment interior nodes **** +** Segment interior nodes store blockids for subtree nodes and terms +** to describe what data is stored by the each subtree. Interior +** nodes are written using InteriorWriter, and read using +** InteriorReader. InteriorWriters are created as needed when +** SegmentWriter creates new leaf nodes, or when an interior node +** itself grows too big and must be split. The format of interior +** nodes: +** +** varint iHeight; (height from leaf level, always >0) +** varint iBlockid; (block id of node's leftmost subtree) +** optional { +** varint nTerm; (length of first term) +** char pTerm[nTerm]; (content of first term) +** array { +** (further terms are delta-encoded) +** varint nPrefix; (length of shared prefix with previous term) +** varint nSuffix; (length of unshared suffix) +** char pTermSuffix[nSuffix]; (unshared suffix of next term) +** } +** } +** +** Here, optional { X } means an optional element, while array { X } +** means zero or more occurrences of X, adjacent in memory. +** +** An interior node encodes n terms separating n+1 subtrees. The +** subtree blocks are contiguous, so only the first subtree's blockid +** is encoded. The subtree at iBlockid will contain all terms less +** than the first term encoded (or all terms if no term is encoded). +** Otherwise, for terms greater than or equal to pTerm[i] but less +** than pTerm[i+1], the subtree for that term will be rooted at +** iBlockid+i. Interior nodes only store enough term data to +** distinguish adjacent children (if the rightmost term of the left +** child is "something", and the leftmost term of the right child is +** "wicked", only "w" is stored). +** +** New data is spilled to a new interior node at the same height when +** the current node exceeds INTERIOR_MAX bytes (default 2048). +** INTERIOR_MIN_TERMS (default 7) keeps large terms from monopolizing +** interior nodes and making the tree too skinny. The interior nodes +** at a given height are naturally tracked by interior nodes at +** height+1, and so on. +** +** +**** Segment directory **** +** The segment directory in table %_segdir stores meta-information for +** merging and deleting segments, and also the root node of the +** segment's tree. +** +** The root node is the top node of the segment's tree after encoding +** the entire segment, restricted to ROOT_MAX bytes (default 1024). +** This could be either a leaf node or an interior node. If the top +** node requires more than ROOT_MAX bytes, it is flushed to %_segments +** and a new root interior node is generated (which should always fit +** within ROOT_MAX because it only needs space for 2 varints, the +** height and the blockid of the previous root). +** +** The meta-information in the segment directory is: +** level - segment level (see below) +** idx - index within level +** - (level,idx uniquely identify a segment) +** start_block - first leaf node +** leaves_end_block - last leaf node +** end_block - last block (including interior nodes) +** root - contents of root node +** +** If the root node is a leaf node, then start_block, +** leaves_end_block, and end_block are all 0. +** +** +**** Segment merging **** +** To amortize update costs, segments are grouped into levels and +** merged in batches. Each increase in level represents exponentially +** more documents. +** +** New documents (actually, document updates) are tokenized and +** written individually (using LeafWriter) to a level 0 segment, with +** incrementing idx. When idx reaches MERGE_COUNT (default 16), all +** level 0 segments are merged into a single level 1 segment. Level 1 +** is populated like level 0, and eventually MERGE_COUNT level 1 +** segments are merged to a single level 2 segment (representing +** MERGE_COUNT^2 updates), and so on. +** +** A segment merge traverses all segments at a given level in +** parallel, performing a straightforward sorted merge. Since segment +** leaf nodes are written in to the %_segments table in order, this +** merge traverses the underlying sqlite disk structures efficiently. +** After the merge, all segment blocks from the merged level are +** deleted. +** +** MERGE_COUNT controls how often we merge segments. 16 seems to be +** somewhat of a sweet spot for insertion performance. 32 and 64 show +** very similar performance numbers to 16 on insertion, though they're +** a tiny bit slower (perhaps due to more overhead in merge-time +** sorting). 8 is about 20% slower than 16, 4 about 50% slower than +** 16, 2 about 66% slower than 16. +** +** At query time, high MERGE_COUNT increases the number of segments +** which need to be scanned and merged. For instance, with 100k docs +** inserted: +** +** MERGE_COUNT segments +** 16 25 +** 8 12 +** 4 10 +** 2 6 +** +** This appears to have only a moderate impact on queries for very +** frequent terms (which are somewhat dominated by segment merge +** costs), and infrequent and non-existent terms still seem to be fast +** even with many segments. +** +** TODO(shess) That said, it would be nice to have a better query-side +** argument for MERGE_COUNT of 16. Also, it is possible/likely that +** optimizations to things like doclist merging will swing the sweet +** spot around. +** +** +** +**** Handling of deletions and updates **** +** Since we're using a segmented structure, with no docid-oriented +** index into the term index, we clearly cannot simply update the term +** index when a document is deleted or updated. For deletions, we +** write an empty doclist (varint(docid) varint(POS_END)), for updates +** we simply write the new doclist. Segment merges overwrite older +** data for a particular docid with newer data, so deletes or updates +** will eventually overtake the earlier data and knock it out. The +** query logic likewise merges doclists so that newer data knocks out +** older data. +*/ + +#include "fts3Int.h" +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) + +#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE) +# define SQLITE_CORE 1 +#endif + +#include <assert.h> +#include <stdlib.h> +#include <stddef.h> +#include <stdio.h> +#include <string.h> +#include <stdarg.h> + +#include "fts3.h" +#ifndef SQLITE_CORE +# include "sqlite3ext.h" + SQLITE_EXTENSION_INIT1 +#endif + +typedef struct Fts3HashWrapper Fts3HashWrapper; +struct Fts3HashWrapper { + Fts3Hash hash; /* Hash table */ + int nRef; /* Number of pointers to this object */ +}; + +static int fts3EvalNext(Fts3Cursor *pCsr); +static int fts3EvalStart(Fts3Cursor *pCsr); +static int fts3TermSegReaderCursor( + Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **); + +/* +** This variable is set to false when running tests for which the on disk +** structures should not be corrupt. Otherwise, true. If it is false, extra +** assert() conditions in the fts3 code are activated - conditions that are +** only true if it is guaranteed that the fts3 database is not corrupt. +*/ +#ifdef SQLITE_DEBUG +int sqlite3_fts3_may_be_corrupt = 1; +#endif + +/* +** Write a 64-bit variable-length integer to memory starting at p[0]. +** The length of data written will be between 1 and FTS3_VARINT_MAX bytes. +** The number of bytes written is returned. +*/ +int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){ + unsigned char *q = (unsigned char *) p; + sqlite_uint64 vu = v; + do{ + *q++ = (unsigned char) ((vu & 0x7f) | 0x80); + vu >>= 7; + }while( vu!=0 ); + q[-1] &= 0x7f; /* turn off high bit in final byte */ + assert( q - (unsigned char *)p <= FTS3_VARINT_MAX ); + return (int) (q - (unsigned char *)p); +} + +#define GETVARINT_STEP(v, ptr, shift, mask1, mask2, var, ret) \ + v = (v & mask1) | ( (*(const unsigned char*)(ptr++)) << shift ); \ + if( (v & mask2)==0 ){ var = v; return ret; } +#define GETVARINT_INIT(v, ptr, shift, mask1, mask2, var, ret) \ + v = (*ptr++); \ + if( (v & mask2)==0 ){ var = v; return ret; } + +int sqlite3Fts3GetVarintU(const char *pBuf, sqlite_uint64 *v){ + const unsigned char *p = (const unsigned char*)pBuf; + const unsigned char *pStart = p; + u32 a; + u64 b; + int shift; + + GETVARINT_INIT(a, p, 0, 0x00, 0x80, *v, 1); + GETVARINT_STEP(a, p, 7, 0x7F, 0x4000, *v, 2); + GETVARINT_STEP(a, p, 14, 0x3FFF, 0x200000, *v, 3); + GETVARINT_STEP(a, p, 21, 0x1FFFFF, 0x10000000, *v, 4); + b = (a & 0x0FFFFFFF ); + + for(shift=28; shift<=63; shift+=7){ + u64 c = *p++; + b += (c&0x7F) << shift; + if( (c & 0x80)==0 ) break; + } + *v = b; + return (int)(p - pStart); +} + +/* +** Read a 64-bit variable-length integer from memory starting at p[0]. +** Return the number of bytes read, or 0 on error. +** The value is stored in *v. +*/ +int sqlite3Fts3GetVarint(const char *pBuf, sqlite_int64 *v){ + return sqlite3Fts3GetVarintU(pBuf, (sqlite3_uint64*)v); +} + +/* +** Read a 64-bit variable-length integer from memory starting at p[0] and +** not extending past pEnd[-1]. +** Return the number of bytes read, or 0 on error. +** The value is stored in *v. +*/ +int sqlite3Fts3GetVarintBounded( + const char *pBuf, + const char *pEnd, + sqlite_int64 *v +){ + const unsigned char *p = (const unsigned char*)pBuf; + const unsigned char *pStart = p; + const unsigned char *pX = (const unsigned char*)pEnd; + u64 b = 0; + int shift; + for(shift=0; shift<=63; shift+=7){ + u64 c = p<pX ? *p : 0; + p++; + b += (c&0x7F) << shift; + if( (c & 0x80)==0 ) break; + } + *v = b; + return (int)(p - pStart); +} + +/* +** Similar to sqlite3Fts3GetVarint(), except that the output is truncated to +** a non-negative 32-bit integer before it is returned. +*/ +int sqlite3Fts3GetVarint32(const char *p, int *pi){ + const unsigned char *ptr = (const unsigned char*)p; + u32 a; + +#ifndef fts3GetVarint32 + GETVARINT_INIT(a, ptr, 0, 0x00, 0x80, *pi, 1); +#else + a = (*ptr++); + assert( a & 0x80 ); +#endif + + GETVARINT_STEP(a, ptr, 7, 0x7F, 0x4000, *pi, 2); + GETVARINT_STEP(a, ptr, 14, 0x3FFF, 0x200000, *pi, 3); + GETVARINT_STEP(a, ptr, 21, 0x1FFFFF, 0x10000000, *pi, 4); + a = (a & 0x0FFFFFFF ); + *pi = (int)(a | ((u32)(*ptr & 0x07) << 28)); + assert( 0==(a & 0x80000000) ); + assert( *pi>=0 ); + return 5; +} + +/* +** Return the number of bytes required to encode v as a varint +*/ +int sqlite3Fts3VarintLen(sqlite3_uint64 v){ + int i = 0; + do{ + i++; + v >>= 7; + }while( v!=0 ); + return i; +} + +/* +** Convert an SQL-style quoted string into a normal string by removing +** the quote characters. The conversion is done in-place. If the +** input does not begin with a quote character, then this routine +** is a no-op. +** +** Examples: +** +** "abc" becomes abc +** 'xyz' becomes xyz +** [pqr] becomes pqr +** `mno` becomes mno +** +*/ +void sqlite3Fts3Dequote(char *z){ + char quote; /* Quote character (if any ) */ + + quote = z[0]; + if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){ + int iIn = 1; /* Index of next byte to read from input */ + int iOut = 0; /* Index of next byte to write to output */ + + /* If the first byte was a '[', then the close-quote character is a ']' */ + if( quote=='[' ) quote = ']'; + + while( z[iIn] ){ + if( z[iIn]==quote ){ + if( z[iIn+1]!=quote ) break; + z[iOut++] = quote; + iIn += 2; + }else{ + z[iOut++] = z[iIn++]; + } + } + z[iOut] = '\0'; + } +} + +/* +** Read a single varint from the doclist at *pp and advance *pp to point +** to the first byte past the end of the varint. Add the value of the varint +** to *pVal. +*/ +static void fts3GetDeltaVarint(char **pp, sqlite3_int64 *pVal){ + sqlite3_int64 iVal; + *pp += sqlite3Fts3GetVarint(*pp, &iVal); + *pVal += iVal; +} + +/* +** When this function is called, *pp points to the first byte following a +** varint that is part of a doclist (or position-list, or any other list +** of varints). This function moves *pp to point to the start of that varint, +** and sets *pVal by the varint value. +** +** Argument pStart points to the first byte of the doclist that the +** varint is part of. +*/ +static void fts3GetReverseVarint( + char **pp, + char *pStart, + sqlite3_int64 *pVal +){ + sqlite3_int64 iVal; + char *p; + + /* Pointer p now points at the first byte past the varint we are + ** interested in. So, unless the doclist is corrupt, the 0x80 bit is + ** clear on character p[-1]. */ + for(p = (*pp)-2; p>=pStart && *p&0x80; p--); + p++; + *pp = p; + + sqlite3Fts3GetVarint(p, &iVal); + *pVal = iVal; +} + +/* +** The xDisconnect() virtual table method. +*/ +static int fts3DisconnectMethod(sqlite3_vtab *pVtab){ + Fts3Table *p = (Fts3Table *)pVtab; + int i; + + assert( p->nPendingData==0 ); + assert( p->pSegments==0 ); + + /* Free any prepared statements held */ + sqlite3_finalize(p->pSeekStmt); + for(i=0; i<SizeofArray(p->aStmt); i++){ + sqlite3_finalize(p->aStmt[i]); + } + sqlite3_free(p->zSegmentsTbl); + sqlite3_free(p->zReadExprlist); + sqlite3_free(p->zWriteExprlist); + sqlite3_free(p->zContentTbl); + sqlite3_free(p->zLanguageid); + + /* Invoke the tokenizer destructor to free the tokenizer. */ + p->pTokenizer->pModule->xDestroy(p->pTokenizer); + + sqlite3_free(p); + return SQLITE_OK; +} + +/* +** Write an error message into *pzErr +*/ +void sqlite3Fts3ErrMsg(char **pzErr, const char *zFormat, ...){ + va_list ap; + sqlite3_free(*pzErr); + va_start(ap, zFormat); + *pzErr = sqlite3_vmprintf(zFormat, ap); + va_end(ap); +} + +/* +** Construct one or more SQL statements from the format string given +** and then evaluate those statements. The success code is written +** into *pRc. +** +** If *pRc is initially non-zero then this routine is a no-op. +*/ +static void fts3DbExec( + int *pRc, /* Success code */ + sqlite3 *db, /* Database in which to run SQL */ + const char *zFormat, /* Format string for SQL */ + ... /* Arguments to the format string */ +){ + va_list ap; + char *zSql; + if( *pRc ) return; + va_start(ap, zFormat); + zSql = sqlite3_vmprintf(zFormat, ap); + va_end(ap); + if( zSql==0 ){ + *pRc = SQLITE_NOMEM; + }else{ + *pRc = sqlite3_exec(db, zSql, 0, 0, 0); + sqlite3_free(zSql); + } +} + +/* +** The xDestroy() virtual table method. +*/ +static int fts3DestroyMethod(sqlite3_vtab *pVtab){ + Fts3Table *p = (Fts3Table *)pVtab; + int rc = SQLITE_OK; /* Return code */ + const char *zDb = p->zDb; /* Name of database (e.g. "main", "temp") */ + sqlite3 *db = p->db; /* Database handle */ + + /* Drop the shadow tables */ + fts3DbExec(&rc, db, + "DROP TABLE IF EXISTS %Q.'%q_segments';" + "DROP TABLE IF EXISTS %Q.'%q_segdir';" + "DROP TABLE IF EXISTS %Q.'%q_docsize';" + "DROP TABLE IF EXISTS %Q.'%q_stat';" + "%s DROP TABLE IF EXISTS %Q.'%q_content';", + zDb, p->zName, + zDb, p->zName, + zDb, p->zName, + zDb, p->zName, + (p->zContentTbl ? "--" : ""), zDb,p->zName + ); + + /* If everything has worked, invoke fts3DisconnectMethod() to free the + ** memory associated with the Fts3Table structure and return SQLITE_OK. + ** Otherwise, return an SQLite error code. + */ + return (rc==SQLITE_OK ? fts3DisconnectMethod(pVtab) : rc); +} + + +/* +** Invoke sqlite3_declare_vtab() to declare the schema for the FTS3 table +** passed as the first argument. This is done as part of the xConnect() +** and xCreate() methods. +** +** If *pRc is non-zero when this function is called, it is a no-op. +** Otherwise, if an error occurs, an SQLite error code is stored in *pRc +** before returning. +*/ +static void fts3DeclareVtab(int *pRc, Fts3Table *p){ + if( *pRc==SQLITE_OK ){ + int i; /* Iterator variable */ + int rc; /* Return code */ + char *zSql; /* SQL statement passed to declare_vtab() */ + char *zCols; /* List of user defined columns */ + const char *zLanguageid; + + zLanguageid = (p->zLanguageid ? p->zLanguageid : "__langid"); + sqlite3_vtab_config(p->db, SQLITE_VTAB_CONSTRAINT_SUPPORT, 1); + + /* Create a list of user columns for the virtual table */ + zCols = sqlite3_mprintf("%Q, ", p->azColumn[0]); + for(i=1; zCols && i<p->nColumn; i++){ + zCols = sqlite3_mprintf("%z%Q, ", zCols, p->azColumn[i]); + } + + /* Create the whole "CREATE TABLE" statement to pass to SQLite */ + zSql = sqlite3_mprintf( + "CREATE TABLE x(%s %Q HIDDEN, docid HIDDEN, %Q HIDDEN)", + zCols, p->zName, zLanguageid + ); + if( !zCols || !zSql ){ + rc = SQLITE_NOMEM; + }else{ + rc = sqlite3_declare_vtab(p->db, zSql); + } + + sqlite3_free(zSql); + sqlite3_free(zCols); + *pRc = rc; + } +} + +/* +** Create the %_stat table if it does not already exist. +*/ +void sqlite3Fts3CreateStatTable(int *pRc, Fts3Table *p){ + fts3DbExec(pRc, p->db, + "CREATE TABLE IF NOT EXISTS %Q.'%q_stat'" + "(id INTEGER PRIMARY KEY, value BLOB);", + p->zDb, p->zName + ); + if( (*pRc)==SQLITE_OK ) p->bHasStat = 1; +} + +/* +** Create the backing store tables (%_content, %_segments and %_segdir) +** required by the FTS3 table passed as the only argument. This is done +** as part of the vtab xCreate() method. +** +** If the p->bHasDocsize boolean is true (indicating that this is an +** FTS4 table, not an FTS3 table) then also create the %_docsize and +** %_stat tables required by FTS4. +*/ +static int fts3CreateTables(Fts3Table *p){ + int rc = SQLITE_OK; /* Return code */ + int i; /* Iterator variable */ + sqlite3 *db = p->db; /* The database connection */ + + if( p->zContentTbl==0 ){ + const char *zLanguageid = p->zLanguageid; + char *zContentCols; /* Columns of %_content table */ + + /* Create a list of user columns for the content table */ + zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY"); + for(i=0; zContentCols && i<p->nColumn; i++){ + char *z = p->azColumn[i]; + zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z); + } + if( zLanguageid && zContentCols ){ + zContentCols = sqlite3_mprintf("%z, langid", zContentCols, zLanguageid); + } + if( zContentCols==0 ) rc = SQLITE_NOMEM; + + /* Create the content table */ + fts3DbExec(&rc, db, + "CREATE TABLE %Q.'%q_content'(%s)", + p->zDb, p->zName, zContentCols + ); + sqlite3_free(zContentCols); + } + + /* Create other tables */ + fts3DbExec(&rc, db, + "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);", + p->zDb, p->zName + ); + fts3DbExec(&rc, db, + "CREATE TABLE %Q.'%q_segdir'(" + "level INTEGER," + "idx INTEGER," + "start_block INTEGER," + "leaves_end_block INTEGER," + "end_block INTEGER," + "root BLOB," + "PRIMARY KEY(level, idx)" + ");", + p->zDb, p->zName + ); + if( p->bHasDocsize ){ + fts3DbExec(&rc, db, + "CREATE TABLE %Q.'%q_docsize'(docid INTEGER PRIMARY KEY, size BLOB);", + p->zDb, p->zName + ); + } + assert( p->bHasStat==p->bFts4 ); + if( p->bHasStat ){ + sqlite3Fts3CreateStatTable(&rc, p); + } + return rc; +} + +/* +** Store the current database page-size in bytes in p->nPgsz. +** +** If *pRc is non-zero when this function is called, it is a no-op. +** Otherwise, if an error occurs, an SQLite error code is stored in *pRc +** before returning. +*/ +static void fts3DatabasePageSize(int *pRc, Fts3Table *p){ + if( *pRc==SQLITE_OK ){ + int rc; /* Return code */ + char *zSql; /* SQL text "PRAGMA %Q.page_size" */ + sqlite3_stmt *pStmt; /* Compiled "PRAGMA %Q.page_size" statement */ + + zSql = sqlite3_mprintf("PRAGMA %Q.page_size", p->zDb); + if( !zSql ){ + rc = SQLITE_NOMEM; + }else{ + rc = sqlite3_prepare(p->db, zSql, -1, &pStmt, 0); + if( rc==SQLITE_OK ){ + sqlite3_step(pStmt); + p->nPgsz = sqlite3_column_int(pStmt, 0); + rc = sqlite3_finalize(pStmt); + }else if( rc==SQLITE_AUTH ){ + p->nPgsz = 1024; + rc = SQLITE_OK; + } + } + assert( p->nPgsz>0 || rc!=SQLITE_OK ); + sqlite3_free(zSql); + *pRc = rc; + } +} + +/* +** "Special" FTS4 arguments are column specifications of the following form: +** +** <key> = <value> +** +** There may not be whitespace surrounding the "=" character. The <value> +** term may be quoted, but the <key> may not. +*/ +static int fts3IsSpecialColumn( + const char *z, + int *pnKey, + char **pzValue +){ + char *zValue; + const char *zCsr = z; + + while( *zCsr!='=' ){ + if( *zCsr=='\0' ) return 0; + zCsr++; + } + + *pnKey = (int)(zCsr-z); + zValue = sqlite3_mprintf("%s", &zCsr[1]); + if( zValue ){ + sqlite3Fts3Dequote(zValue); + } + *pzValue = zValue; + return 1; +} + +/* +** Append the output of a printf() style formatting to an existing string. +*/ +static void fts3Appendf( + int *pRc, /* IN/OUT: Error code */ + char **pz, /* IN/OUT: Pointer to string buffer */ + const char *zFormat, /* Printf format string to append */ + ... /* Arguments for printf format string */ +){ + if( *pRc==SQLITE_OK ){ + va_list ap; + char *z; + va_start(ap, zFormat); + z = sqlite3_vmprintf(zFormat, ap); + va_end(ap); + if( z && *pz ){ + char *z2 = sqlite3_mprintf("%s%s", *pz, z); + sqlite3_free(z); + z = z2; + } + if( z==0 ) *pRc = SQLITE_NOMEM; + sqlite3_free(*pz); + *pz = z; + } +} + +/* +** Return a copy of input string zInput enclosed in double-quotes (") and +** with all double quote characters escaped. For example: +** +** fts3QuoteId("un \"zip\"") -> "un \"\"zip\"\"" +** +** The pointer returned points to memory obtained from sqlite3_malloc(). It +** is the callers responsibility to call sqlite3_free() to release this +** memory. +*/ +static char *fts3QuoteId(char const *zInput){ + sqlite3_int64 nRet; + char *zRet; + nRet = 2 + (int)strlen(zInput)*2 + 1; + zRet = sqlite3_malloc64(nRet); + if( zRet ){ + int i; + char *z = zRet; + *(z++) = '"'; + for(i=0; zInput[i]; i++){ + if( zInput[i]=='"' ) *(z++) = '"'; + *(z++) = zInput[i]; + } + *(z++) = '"'; + *(z++) = '\0'; + } + return zRet; +} + +/* +** Return a list of comma separated SQL expressions and a FROM clause that +** could be used in a SELECT statement such as the following: +** +** SELECT <list of expressions> FROM %_content AS x ... +** +** to return the docid, followed by each column of text data in order +** from left to write. If parameter zFunc is not NULL, then instead of +** being returned directly each column of text data is passed to an SQL +** function named zFunc first. For example, if zFunc is "unzip" and the +** table has the three user-defined columns "a", "b", and "c", the following +** string is returned: +** +** "docid, unzip(x.'a'), unzip(x.'b'), unzip(x.'c') FROM %_content AS x" +** +** The pointer returned points to a buffer allocated by sqlite3_malloc(). It +** is the responsibility of the caller to eventually free it. +** +** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and +** a NULL pointer is returned). Otherwise, if an OOM error is encountered +** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If +** no error occurs, *pRc is left unmodified. +*/ +static char *fts3ReadExprList(Fts3Table *p, const char *zFunc, int *pRc){ + char *zRet = 0; + char *zFree = 0; + char *zFunction; + int i; + + if( p->zContentTbl==0 ){ + if( !zFunc ){ + zFunction = ""; + }else{ + zFree = zFunction = fts3QuoteId(zFunc); + } + fts3Appendf(pRc, &zRet, "docid"); + for(i=0; i<p->nColumn; i++){ + fts3Appendf(pRc, &zRet, ",%s(x.'c%d%q')", zFunction, i, p->azColumn[i]); + } + if( p->zLanguageid ){ + fts3Appendf(pRc, &zRet, ", x.%Q", "langid"); + } + sqlite3_free(zFree); + }else{ + fts3Appendf(pRc, &zRet, "rowid"); + for(i=0; i<p->nColumn; i++){ + fts3Appendf(pRc, &zRet, ", x.'%q'", p->azColumn[i]); + } + if( p->zLanguageid ){ + fts3Appendf(pRc, &zRet, ", x.%Q", p->zLanguageid); + } + } + fts3Appendf(pRc, &zRet, " FROM '%q'.'%q%s' AS x", + p->zDb, + (p->zContentTbl ? p->zContentTbl : p->zName), + (p->zContentTbl ? "" : "_content") + ); + return zRet; +} + +/* +** Return a list of N comma separated question marks, where N is the number +** of columns in the %_content table (one for the docid plus one for each +** user-defined text column). +** +** If argument zFunc is not NULL, then all but the first question mark +** is preceded by zFunc and an open bracket, and followed by a closed +** bracket. For example, if zFunc is "zip" and the FTS3 table has three +** user-defined text columns, the following string is returned: +** +** "?, zip(?), zip(?), zip(?)" +** +** The pointer returned points to a buffer allocated by sqlite3_malloc(). It +** is the responsibility of the caller to eventually free it. +** +** If *pRc is not SQLITE_OK when this function is called, it is a no-op (and +** a NULL pointer is returned). Otherwise, if an OOM error is encountered +** by this function, NULL is returned and *pRc is set to SQLITE_NOMEM. If +** no error occurs, *pRc is left unmodified. +*/ +static char *fts3WriteExprList(Fts3Table *p, const char *zFunc, int *pRc){ + char *zRet = 0; + char *zFree = 0; + char *zFunction; + int i; + + if( !zFunc ){ + zFunction = ""; + }else{ + zFree = zFunction = fts3QuoteId(zFunc); + } + fts3Appendf(pRc, &zRet, "?"); + for(i=0; i<p->nColumn; i++){ + fts3Appendf(pRc, &zRet, ",%s(?)", zFunction); + } + if( p->zLanguageid ){ + fts3Appendf(pRc, &zRet, ", ?"); + } + sqlite3_free(zFree); + return zRet; +} + +/* +** Buffer z contains a positive integer value encoded as utf-8 text. +** Decode this value and store it in *pnOut, returning the number of bytes +** consumed. If an overflow error occurs return a negative value. +*/ +int sqlite3Fts3ReadInt(const char *z, int *pnOut){ + u64 iVal = 0; + int i; + for(i=0; z[i]>='0' && z[i]<='9'; i++){ + iVal = iVal*10 + (z[i] - '0'); + if( iVal>0x7FFFFFFF ) return -1; + } + *pnOut = (int)iVal; + return i; +} + +/* +** This function interprets the string at (*pp) as a non-negative integer +** value. It reads the integer and sets *pnOut to the value read, then +** sets *pp to point to the byte immediately following the last byte of +** the integer value. +** +** Only decimal digits ('0'..'9') may be part of an integer value. +** +** If *pp does not being with a decimal digit SQLITE_ERROR is returned and +** the output value undefined. Otherwise SQLITE_OK is returned. +** +** This function is used when parsing the "prefix=" FTS4 parameter. +*/ +static int fts3GobbleInt(const char **pp, int *pnOut){ + const int MAX_NPREFIX = 10000000; + int nInt = 0; /* Output value */ + int nByte; + nByte = sqlite3Fts3ReadInt(*pp, &nInt); + if( nInt>MAX_NPREFIX ){ + nInt = 0; + } + if( nByte==0 ){ + return SQLITE_ERROR; + } + *pnOut = nInt; + *pp += nByte; + return SQLITE_OK; +} + +/* +** This function is called to allocate an array of Fts3Index structures +** representing the indexes maintained by the current FTS table. FTS tables +** always maintain the main "terms" index, but may also maintain one or +** more "prefix" indexes, depending on the value of the "prefix=" parameter +** (if any) specified as part of the CREATE VIRTUAL TABLE statement. +** +** Argument zParam is passed the value of the "prefix=" option if one was +** specified, or NULL otherwise. +** +** If no error occurs, SQLITE_OK is returned and *apIndex set to point to +** the allocated array. *pnIndex is set to the number of elements in the +** array. If an error does occur, an SQLite error code is returned. +** +** Regardless of whether or not an error is returned, it is the responsibility +** of the caller to call sqlite3_free() on the output array to free it. +*/ +static int fts3PrefixParameter( + const char *zParam, /* ABC in prefix=ABC parameter to parse */ + int *pnIndex, /* OUT: size of *apIndex[] array */ + struct Fts3Index **apIndex /* OUT: Array of indexes for this table */ +){ + struct Fts3Index *aIndex; /* Allocated array */ + int nIndex = 1; /* Number of entries in array */ + + if( zParam && zParam[0] ){ + const char *p; + nIndex++; + for(p=zParam; *p; p++){ + if( *p==',' ) nIndex++; + } + } + + aIndex = sqlite3_malloc64(sizeof(struct Fts3Index) * nIndex); + *apIndex = aIndex; + if( !aIndex ){ + return SQLITE_NOMEM; + } + + memset(aIndex, 0, sizeof(struct Fts3Index) * nIndex); + if( zParam ){ + const char *p = zParam; + int i; + for(i=1; i<nIndex; i++){ + int nPrefix = 0; + if( fts3GobbleInt(&p, &nPrefix) ) return SQLITE_ERROR; + assert( nPrefix>=0 ); + if( nPrefix==0 ){ + nIndex--; + i--; + }else{ + aIndex[i].nPrefix = nPrefix; + } + p++; + } + } + + *pnIndex = nIndex; + return SQLITE_OK; +} + +/* +** This function is called when initializing an FTS4 table that uses the +** content=xxx option. It determines the number of and names of the columns +** of the new FTS4 table. +** +** The third argument passed to this function is the value passed to the +** config=xxx option (i.e. "xxx"). This function queries the database for +** a table of that name. If found, the output variables are populated +** as follows: +** +** *pnCol: Set to the number of columns table xxx has, +** +** *pnStr: Set to the total amount of space required to store a copy +** of each columns name, including the nul-terminator. +** +** *pazCol: Set to point to an array of *pnCol strings. Each string is +** the name of the corresponding column in table xxx. The array +** and its contents are allocated using a single allocation. It +** is the responsibility of the caller to free this allocation +** by eventually passing the *pazCol value to sqlite3_free(). +** +** If the table cannot be found, an error code is returned and the output +** variables are undefined. Or, if an OOM is encountered, SQLITE_NOMEM is +** returned (and the output variables are undefined). +*/ +static int fts3ContentColumns( + sqlite3 *db, /* Database handle */ + const char *zDb, /* Name of db (i.e. "main", "temp" etc.) */ + const char *zTbl, /* Name of content table */ + const char ***pazCol, /* OUT: Malloc'd array of column names */ + int *pnCol, /* OUT: Size of array *pazCol */ + int *pnStr, /* OUT: Bytes of string content */ + char **pzErr /* OUT: error message */ +){ + int rc = SQLITE_OK; /* Return code */ + char *zSql; /* "SELECT *" statement on zTbl */ + sqlite3_stmt *pStmt = 0; /* Compiled version of zSql */ + + zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", zDb, zTbl); + if( !zSql ){ + rc = SQLITE_NOMEM; + }else{ + rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); + if( rc!=SQLITE_OK ){ + sqlite3Fts3ErrMsg(pzErr, "%s", sqlite3_errmsg(db)); + } + } + sqlite3_free(zSql); + + if( rc==SQLITE_OK ){ + const char **azCol; /* Output array */ + sqlite3_int64 nStr = 0; /* Size of all column names (incl. 0x00) */ + int nCol; /* Number of table columns */ + int i; /* Used to iterate through columns */ + + /* Loop through the returned columns. Set nStr to the number of bytes of + ** space required to store a copy of each column name, including the + ** nul-terminator byte. */ + nCol = sqlite3_column_count(pStmt); + for(i=0; i<nCol; i++){ + const char *zCol = sqlite3_column_name(pStmt, i); + nStr += strlen(zCol) + 1; + } + + /* Allocate and populate the array to return. */ + azCol = (const char **)sqlite3_malloc64(sizeof(char *) * nCol + nStr); + if( azCol==0 ){ + rc = SQLITE_NOMEM; + }else{ + char *p = (char *)&azCol[nCol]; + for(i=0; i<nCol; i++){ + const char *zCol = sqlite3_column_name(pStmt, i); + int n = (int)strlen(zCol)+1; + memcpy(p, zCol, n); + azCol[i] = p; + p += n; + } + } + sqlite3_finalize(pStmt); + + /* Set the output variables. */ + *pnCol = nCol; + *pnStr = nStr; + *pazCol = azCol; + } + + return rc; +} + +/* +** This function is the implementation of both the xConnect and xCreate +** methods of the FTS3 virtual table. +** +** The argv[] array contains the following: +** +** argv[0] -> module name ("fts3" or "fts4") +** argv[1] -> database name +** argv[2] -> table name +** argv[...] -> "column name" and other module argument fields. +*/ +static int fts3InitVtab( + int isCreate, /* True for xCreate, false for xConnect */ + sqlite3 *db, /* The SQLite database connection */ + void *pAux, /* Hash table containing tokenizers */ + int argc, /* Number of elements in argv array */ + const char * const *argv, /* xCreate/xConnect argument array */ + sqlite3_vtab **ppVTab, /* Write the resulting vtab structure here */ + char **pzErr /* Write any error message here */ +){ + Fts3Hash *pHash = &((Fts3HashWrapper*)pAux)->hash; + Fts3Table *p = 0; /* Pointer to allocated vtab */ + int rc = SQLITE_OK; /* Return code */ + int i; /* Iterator variable */ + sqlite3_int64 nByte; /* Size of allocation used for *p */ + int iCol; /* Column index */ + int nString = 0; /* Bytes required to hold all column names */ + int nCol = 0; /* Number of columns in the FTS table */ + char *zCsr; /* Space for holding column names */ + int nDb; /* Bytes required to hold database name */ + int nName; /* Bytes required to hold table name */ + int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */ + const char **aCol; /* Array of column names */ + sqlite3_tokenizer *pTokenizer = 0; /* Tokenizer for this table */ + + int nIndex = 0; /* Size of aIndex[] array */ + struct Fts3Index *aIndex = 0; /* Array of indexes for this table */ + + /* The results of parsing supported FTS4 key=value options: */ + int bNoDocsize = 0; /* True to omit %_docsize table */ + int bDescIdx = 0; /* True to store descending indexes */ + char *zPrefix = 0; /* Prefix parameter value (or NULL) */ + char *zCompress = 0; /* compress=? parameter (or NULL) */ + char *zUncompress = 0; /* uncompress=? parameter (or NULL) */ + char *zContent = 0; /* content=? parameter (or NULL) */ + char *zLanguageid = 0; /* languageid=? parameter (or NULL) */ + char **azNotindexed = 0; /* The set of notindexed= columns */ + int nNotindexed = 0; /* Size of azNotindexed[] array */ + + assert( strlen(argv[0])==4 ); + assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4) + || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4) + ); + + nDb = (int)strlen(argv[1]) + 1; + nName = (int)strlen(argv[2]) + 1; + + nByte = sizeof(const char *) * (argc-2); + aCol = (const char **)sqlite3_malloc64(nByte); + if( aCol ){ + memset((void*)aCol, 0, nByte); + azNotindexed = (char **)sqlite3_malloc64(nByte); + } + if( azNotindexed ){ + memset(azNotindexed, 0, nByte); + } + if( !aCol || !azNotindexed ){ + rc = SQLITE_NOMEM; + goto fts3_init_out; + } + + /* Loop through all of the arguments passed by the user to the FTS3/4 + ** module (i.e. all the column names and special arguments). This loop + ** does the following: + ** + ** + Figures out the number of columns the FTSX table will have, and + ** the number of bytes of space that must be allocated to store copies + ** of the column names. + ** + ** + If there is a tokenizer specification included in the arguments, + ** initializes the tokenizer pTokenizer. + */ + for(i=3; rc==SQLITE_OK && i<argc; i++){ + char const *z = argv[i]; + int nKey; + char *zVal; + + /* Check if this is a tokenizer specification */ + if( !pTokenizer + && strlen(z)>8 + && 0==sqlite3_strnicmp(z, "tokenize", 8) + && 0==sqlite3Fts3IsIdChar(z[8]) + ){ + rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr); + } + + /* Check if it is an FTS4 special argument. */ + else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){ + struct Fts4Option { + const char *zOpt; + int nOpt; + } aFts4Opt[] = { + { "matchinfo", 9 }, /* 0 -> MATCHINFO */ + { "prefix", 6 }, /* 1 -> PREFIX */ + { "compress", 8 }, /* 2 -> COMPRESS */ + { "uncompress", 10 }, /* 3 -> UNCOMPRESS */ + { "order", 5 }, /* 4 -> ORDER */ + { "content", 7 }, /* 5 -> CONTENT */ + { "languageid", 10 }, /* 6 -> LANGUAGEID */ + { "notindexed", 10 } /* 7 -> NOTINDEXED */ + }; + + int iOpt; + if( !zVal ){ + rc = SQLITE_NOMEM; + }else{ + for(iOpt=0; iOpt<SizeofArray(aFts4Opt); iOpt++){ + struct Fts4Option *pOp = &aFts4Opt[iOpt]; + if( nKey==pOp->nOpt && !sqlite3_strnicmp(z, pOp->zOpt, pOp->nOpt) ){ + break; + } + } + switch( iOpt ){ + case 0: /* MATCHINFO */ + if( strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "fts3", 4) ){ + sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo: %s", zVal); + rc = SQLITE_ERROR; + } + bNoDocsize = 1; + break; + + case 1: /* PREFIX */ + sqlite3_free(zPrefix); + zPrefix = zVal; + zVal = 0; + break; + + case 2: /* COMPRESS */ + sqlite3_free(zCompress); + zCompress = zVal; + zVal = 0; + break; + + case 3: /* UNCOMPRESS */ + sqlite3_free(zUncompress); + zUncompress = zVal; + zVal = 0; + break; + + case 4: /* ORDER */ + if( (strlen(zVal)!=3 || sqlite3_strnicmp(zVal, "asc", 3)) + && (strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "desc", 4)) + ){ + sqlite3Fts3ErrMsg(pzErr, "unrecognized order: %s", zVal); + rc = SQLITE_ERROR; + } + bDescIdx = (zVal[0]=='d' || zVal[0]=='D'); + break; + + case 5: /* CONTENT */ + sqlite3_free(zContent); + zContent = zVal; + zVal = 0; + break; + + case 6: /* LANGUAGEID */ + assert( iOpt==6 ); + sqlite3_free(zLanguageid); + zLanguageid = zVal; + zVal = 0; + break; + + case 7: /* NOTINDEXED */ + azNotindexed[nNotindexed++] = zVal; + zVal = 0; + break; + + default: + assert( iOpt==SizeofArray(aFts4Opt) ); + sqlite3Fts3ErrMsg(pzErr, "unrecognized parameter: %s", z); + rc = SQLITE_ERROR; + break; + } + sqlite3_free(zVal); + } + } + + /* Otherwise, the argument is a column name. */ + else { + nString += (int)(strlen(z) + 1); + aCol[nCol++] = z; + } + } + + /* If a content=xxx option was specified, the following: + ** + ** 1. Ignore any compress= and uncompress= options. + ** + ** 2. If no column names were specified as part of the CREATE VIRTUAL + ** TABLE statement, use all columns from the content table. + */ + if( rc==SQLITE_OK && zContent ){ + sqlite3_free(zCompress); + sqlite3_free(zUncompress); + zCompress = 0; + zUncompress = 0; + if( nCol==0 ){ + sqlite3_free((void*)aCol); + aCol = 0; + rc = fts3ContentColumns(db, argv[1], zContent,&aCol,&nCol,&nString,pzErr); + + /* If a languageid= option was specified, remove the language id + ** column from the aCol[] array. */ + if( rc==SQLITE_OK && zLanguageid ){ + int j; + for(j=0; j<nCol; j++){ + if( sqlite3_stricmp(zLanguageid, aCol[j])==0 ){ + int k; + for(k=j; k<nCol; k++) aCol[k] = aCol[k+1]; + nCol--; + break; + } + } + } + } + } + if( rc!=SQLITE_OK ) goto fts3_init_out; + + if( nCol==0 ){ + assert( nString==0 ); + aCol[0] = "content"; + nString = 8; + nCol = 1; + } + + if( pTokenizer==0 ){ + rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr); + if( rc!=SQLITE_OK ) goto fts3_init_out; + } + assert( pTokenizer ); + + rc = fts3PrefixParameter(zPrefix, &nIndex, &aIndex); + if( rc==SQLITE_ERROR ){ + assert( zPrefix ); + sqlite3Fts3ErrMsg(pzErr, "error parsing prefix parameter: %s", zPrefix); + } + if( rc!=SQLITE_OK ) goto fts3_init_out; + + /* Allocate and populate the Fts3Table structure. */ + nByte = sizeof(Fts3Table) + /* Fts3Table */ + nCol * sizeof(char *) + /* azColumn */ + nIndex * sizeof(struct Fts3Index) + /* aIndex */ + nCol * sizeof(u8) + /* abNotindexed */ + nName + /* zName */ + nDb + /* zDb */ + nString; /* Space for azColumn strings */ + p = (Fts3Table*)sqlite3_malloc64(nByte); + if( p==0 ){ + rc = SQLITE_NOMEM; + goto fts3_init_out; + } + memset(p, 0, nByte); + p->db = db; + p->nColumn = nCol; + p->nPendingData = 0; + p->azColumn = (char **)&p[1]; + p->pTokenizer = pTokenizer; + p->nMaxPendingData = FTS3_MAX_PENDING_DATA; + p->bHasDocsize = (isFts4 && bNoDocsize==0); + p->bHasStat = (u8)isFts4; + p->bFts4 = (u8)isFts4; + p->bDescIdx = (u8)bDescIdx; + p->nAutoincrmerge = 0xff; /* 0xff means setting unknown */ + p->zContentTbl = zContent; + p->zLanguageid = zLanguageid; + zContent = 0; + zLanguageid = 0; + TESTONLY( p->inTransaction = -1 ); + TESTONLY( p->mxSavepoint = -1 ); + + p->aIndex = (struct Fts3Index *)&p->azColumn[nCol]; + memcpy(p->aIndex, aIndex, sizeof(struct Fts3Index) * nIndex); + p->nIndex = nIndex; + for(i=0; i<nIndex; i++){ + fts3HashInit(&p->aIndex[i].hPending, FTS3_HASH_STRING, 1); + } + p->abNotindexed = (u8 *)&p->aIndex[nIndex]; + + /* Fill in the zName and zDb fields of the vtab structure. */ + zCsr = (char *)&p->abNotindexed[nCol]; + p->zName = zCsr; + memcpy(zCsr, argv[2], nName); + zCsr += nName; + p->zDb = zCsr; + memcpy(zCsr, argv[1], nDb); + zCsr += nDb; + + /* Fill in the azColumn array */ + for(iCol=0; iCol<nCol; iCol++){ + char *z; + int n = 0; + z = (char *)sqlite3Fts3NextToken(aCol[iCol], &n); + if( n>0 ){ + memcpy(zCsr, z, n); + } + zCsr[n] = '\0'; + sqlite3Fts3Dequote(zCsr); + p->azColumn[iCol] = zCsr; + zCsr += n+1; + assert( zCsr <= &((char *)p)[nByte] ); + } + + /* Fill in the abNotindexed array */ + for(iCol=0; iCol<nCol; iCol++){ + int n = (int)strlen(p->azColumn[iCol]); + for(i=0; i<nNotindexed; i++){ + char *zNot = azNotindexed[i]; + if( zNot && n==(int)strlen(zNot) + && 0==sqlite3_strnicmp(p->azColumn[iCol], zNot, n) + ){ + p->abNotindexed[iCol] = 1; + sqlite3_free(zNot); + azNotindexed[i] = 0; + } + } + } + for(i=0; i<nNotindexed; i++){ + if( azNotindexed[i] ){ + sqlite3Fts3ErrMsg(pzErr, "no such column: %s", azNotindexed[i]); + rc = SQLITE_ERROR; + } + } + + if( rc==SQLITE_OK && (zCompress==0)!=(zUncompress==0) ){ + char const *zMiss = (zCompress==0 ? "compress" : "uncompress"); + rc = SQLITE_ERROR; + sqlite3Fts3ErrMsg(pzErr, "missing %s parameter in fts4 constructor", zMiss); + } + p->zReadExprlist = fts3ReadExprList(p, zUncompress, &rc); + p->zWriteExprlist = fts3WriteExprList(p, zCompress, &rc); + if( rc!=SQLITE_OK ) goto fts3_init_out; + + /* If this is an xCreate call, create the underlying tables in the + ** database. TODO: For xConnect(), it could verify that said tables exist. + */ + if( isCreate ){ + rc = fts3CreateTables(p); + } + + /* Check to see if a legacy fts3 table has been "upgraded" by the + ** addition of a %_stat table so that it can use incremental merge. + */ + if( !isFts4 && !isCreate ){ + p->bHasStat = 2; + } + + /* Figure out the page-size for the database. This is required in order to + ** estimate the cost of loading large doclists from the database. */ + fts3DatabasePageSize(&rc, p); + p->nNodeSize = p->nPgsz-35; + +#if defined(SQLITE_DEBUG)||defined(SQLITE_TEST) + p->nMergeCount = FTS3_MERGE_COUNT; +#endif + + /* Declare the table schema to SQLite. */ + fts3DeclareVtab(&rc, p); + +fts3_init_out: + sqlite3_free(zPrefix); + sqlite3_free(aIndex); + sqlite3_free(zCompress); + sqlite3_free(zUncompress); + sqlite3_free(zContent); + sqlite3_free(zLanguageid); + for(i=0; i<nNotindexed; i++) sqlite3_free(azNotindexed[i]); + sqlite3_free((void *)aCol); + sqlite3_free((void *)azNotindexed); + if( rc!=SQLITE_OK ){ + if( p ){ + fts3DisconnectMethod((sqlite3_vtab *)p); + }else if( pTokenizer ){ + pTokenizer->pModule->xDestroy(pTokenizer); + } + }else{ + assert( p->pSegments==0 ); + *ppVTab = &p->base; + } + return rc; +} + +/* +** The xConnect() and xCreate() methods for the virtual table. All the +** work is done in function fts3InitVtab(). +*/ +static int fts3ConnectMethod( + sqlite3 *db, /* Database connection */ + void *pAux, /* Pointer to tokenizer hash table */ + int argc, /* Number of elements in argv array */ + const char * const *argv, /* xCreate/xConnect argument array */ + sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */ + char **pzErr /* OUT: sqlite3_malloc'd error message */ +){ + return fts3InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr); +} +static int fts3CreateMethod( + sqlite3 *db, /* Database connection */ + void *pAux, /* Pointer to tokenizer hash table */ + int argc, /* Number of elements in argv array */ + const char * const *argv, /* xCreate/xConnect argument array */ + sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */ + char **pzErr /* OUT: sqlite3_malloc'd error message */ +){ + return fts3InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr); +} + +/* +** Set the pIdxInfo->estimatedRows variable to nRow. Unless this +** extension is currently being used by a version of SQLite too old to +** support estimatedRows. In that case this function is a no-op. +*/ +static void fts3SetEstimatedRows(sqlite3_index_info *pIdxInfo, i64 nRow){ +#if SQLITE_VERSION_NUMBER>=3008002 + if( sqlite3_libversion_number()>=3008002 ){ + pIdxInfo->estimatedRows = nRow; + } +#endif +} + +/* +** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this +** extension is currently being used by a version of SQLite too old to +** support index-info flags. In that case this function is a no-op. +*/ +static void fts3SetUniqueFlag(sqlite3_index_info *pIdxInfo){ +#if SQLITE_VERSION_NUMBER>=3008012 + if( sqlite3_libversion_number()>=3008012 ){ + pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE; + } +#endif +} + +/* +** Implementation of the xBestIndex method for FTS3 tables. There +** are three possible strategies, in order of preference: +** +** 1. Direct lookup by rowid or docid. +** 2. Full-text search using a MATCH operator on a non-docid column. +** 3. Linear scan of %_content table. +*/ +static int fts3BestIndexMethod(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){ + Fts3Table *p = (Fts3Table *)pVTab; + int i; /* Iterator variable */ + int iCons = -1; /* Index of constraint to use */ + + int iLangidCons = -1; /* Index of langid=x constraint, if present */ + int iDocidGe = -1; /* Index of docid>=x constraint, if present */ + int iDocidLe = -1; /* Index of docid<=x constraint, if present */ + int iIdx; + + if( p->bLock ){ + return SQLITE_ERROR; + } + + /* By default use a full table scan. This is an expensive option, + ** so search through the constraints to see if a more efficient + ** strategy is possible. + */ + pInfo->idxNum = FTS3_FULLSCAN_SEARCH; + pInfo->estimatedCost = 5000000; + for(i=0; i<pInfo->nConstraint; i++){ + int bDocid; /* True if this constraint is on docid */ + struct sqlite3_index_constraint *pCons = &pInfo->aConstraint[i]; + if( pCons->usable==0 ){ + if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH ){ + /* There exists an unusable MATCH constraint. This means that if + ** the planner does elect to use the results of this call as part + ** of the overall query plan the user will see an "unable to use + ** function MATCH in the requested context" error. To discourage + ** this, return a very high cost here. */ + pInfo->idxNum = FTS3_FULLSCAN_SEARCH; + pInfo->estimatedCost = 1e50; + fts3SetEstimatedRows(pInfo, ((sqlite3_int64)1) << 50); + return SQLITE_OK; + } + continue; + } + + bDocid = (pCons->iColumn<0 || pCons->iColumn==p->nColumn+1); + + /* A direct lookup on the rowid or docid column. Assign a cost of 1.0. */ + if( iCons<0 && pCons->op==SQLITE_INDEX_CONSTRAINT_EQ && bDocid ){ + pInfo->idxNum = FTS3_DOCID_SEARCH; + pInfo->estimatedCost = 1.0; + iCons = i; + } + + /* A MATCH constraint. Use a full-text search. + ** + ** If there is more than one MATCH constraint available, use the first + ** one encountered. If there is both a MATCH constraint and a direct + ** rowid/docid lookup, prefer the MATCH strategy. This is done even + ** though the rowid/docid lookup is faster than a MATCH query, selecting + ** it would lead to an "unable to use function MATCH in the requested + ** context" error. + */ + if( pCons->op==SQLITE_INDEX_CONSTRAINT_MATCH + && pCons->iColumn>=0 && pCons->iColumn<=p->nColumn + ){ + pInfo->idxNum = FTS3_FULLTEXT_SEARCH + pCons->iColumn; + pInfo->estimatedCost = 2.0; + iCons = i; + } + + /* Equality constraint on the langid column */ + if( pCons->op==SQLITE_INDEX_CONSTRAINT_EQ + && pCons->iColumn==p->nColumn + 2 + ){ + iLangidCons = i; + } + + if( bDocid ){ + switch( pCons->op ){ + case SQLITE_INDEX_CONSTRAINT_GE: + case SQLITE_INDEX_CONSTRAINT_GT: + iDocidGe = i; + break; + + case SQLITE_INDEX_CONSTRAINT_LE: + case SQLITE_INDEX_CONSTRAINT_LT: + iDocidLe = i; + break; + } + } + } + + /* If using a docid=? or rowid=? strategy, set the UNIQUE flag. */ + if( pInfo->idxNum==FTS3_DOCID_SEARCH ) fts3SetUniqueFlag(pInfo); + + iIdx = 1; + if( iCons>=0 ){ + pInfo->aConstraintUsage[iCons].argvIndex = iIdx++; + pInfo->aConstraintUsage[iCons].omit = 1; + } + if( iLangidCons>=0 ){ + pInfo->idxNum |= FTS3_HAVE_LANGID; + pInfo->aConstraintUsage[iLangidCons].argvIndex = iIdx++; + } + if( iDocidGe>=0 ){ + pInfo->idxNum |= FTS3_HAVE_DOCID_GE; + pInfo->aConstraintUsage[iDocidGe].argvIndex = iIdx++; + } + if( iDocidLe>=0 ){ + pInfo->idxNum |= FTS3_HAVE_DOCID_LE; + pInfo->aConstraintUsage[iDocidLe].argvIndex = iIdx++; + } + + /* Regardless of the strategy selected, FTS can deliver rows in rowid (or + ** docid) order. Both ascending and descending are possible. + */ + if( pInfo->nOrderBy==1 ){ + struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0]; + if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){ + if( pOrder->desc ){ + pInfo->idxStr = "DESC"; + }else{ + pInfo->idxStr = "ASC"; + } + pInfo->orderByConsumed = 1; + } + } + + assert( p->pSegments==0 ); + return SQLITE_OK; +} + +/* +** Implementation of xOpen method. +*/ +static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){ + sqlite3_vtab_cursor *pCsr; /* Allocated cursor */ + + UNUSED_PARAMETER(pVTab); + + /* Allocate a buffer large enough for an Fts3Cursor structure. If the + ** allocation succeeds, zero it and return SQLITE_OK. Otherwise, + ** if the allocation fails, return SQLITE_NOMEM. + */ + *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor)); + if( !pCsr ){ + return SQLITE_NOMEM; + } + memset(pCsr, 0, sizeof(Fts3Cursor)); + return SQLITE_OK; +} + +/* +** Finalize the statement handle at pCsr->pStmt. +** +** Or, if that statement handle is one created by fts3CursorSeekStmt(), +** and the Fts3Table.pSeekStmt slot is currently NULL, save the statement +** pointer there instead of finalizing it. +*/ +static void fts3CursorFinalizeStmt(Fts3Cursor *pCsr){ + if( pCsr->bSeekStmt ){ + Fts3Table *p = (Fts3Table *)pCsr->base.pVtab; + if( p->pSeekStmt==0 ){ + p->pSeekStmt = pCsr->pStmt; + sqlite3_reset(pCsr->pStmt); + pCsr->pStmt = 0; + } + pCsr->bSeekStmt = 0; + } + sqlite3_finalize(pCsr->pStmt); +} + +/* +** Free all resources currently held by the cursor passed as the only +** argument. +*/ +static void fts3ClearCursor(Fts3Cursor *pCsr){ + fts3CursorFinalizeStmt(pCsr); + sqlite3Fts3FreeDeferredTokens(pCsr); + sqlite3_free(pCsr->aDoclist); + sqlite3Fts3MIBufferFree(pCsr->pMIBuffer); + sqlite3Fts3ExprFree(pCsr->pExpr); + memset(&(&pCsr->base)[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor)); +} + +/* +** Close the cursor. For additional information see the documentation +** on the xClose method of the virtual table interface. +*/ +static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){ + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor; + assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 ); + fts3ClearCursor(pCsr); + assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 ); + sqlite3_free(pCsr); + return SQLITE_OK; +} + +/* +** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then +** compose and prepare an SQL statement of the form: +** +** "SELECT <columns> FROM %_content WHERE rowid = ?" +** +** (or the equivalent for a content=xxx table) and set pCsr->pStmt to +** it. If an error occurs, return an SQLite error code. +*/ +static int fts3CursorSeekStmt(Fts3Cursor *pCsr){ + int rc = SQLITE_OK; + if( pCsr->pStmt==0 ){ + Fts3Table *p = (Fts3Table *)pCsr->base.pVtab; + char *zSql; + if( p->pSeekStmt ){ + pCsr->pStmt = p->pSeekStmt; + p->pSeekStmt = 0; + }else{ + zSql = sqlite3_mprintf("SELECT %s WHERE rowid = ?", p->zReadExprlist); + if( !zSql ) return SQLITE_NOMEM; + p->bLock++; + rc = sqlite3_prepare_v3( + p->db, zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0 + ); + p->bLock--; + sqlite3_free(zSql); + } + if( rc==SQLITE_OK ) pCsr->bSeekStmt = 1; + } + return rc; +} + +/* +** Position the pCsr->pStmt statement so that it is on the row +** of the %_content table that contains the last match. Return +** SQLITE_OK on success. +*/ +static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){ + int rc = SQLITE_OK; + if( pCsr->isRequireSeek ){ + rc = fts3CursorSeekStmt(pCsr); + if( rc==SQLITE_OK ){ + Fts3Table *pTab = (Fts3Table*)pCsr->base.pVtab; + pTab->bLock++; + sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId); + pCsr->isRequireSeek = 0; + if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){ + pTab->bLock--; + return SQLITE_OK; + }else{ + pTab->bLock--; + rc = sqlite3_reset(pCsr->pStmt); + if( rc==SQLITE_OK && ((Fts3Table *)pCsr->base.pVtab)->zContentTbl==0 ){ + /* If no row was found and no error has occurred, then the %_content + ** table is missing a row that is present in the full-text index. + ** The data structures are corrupt. */ + rc = FTS_CORRUPT_VTAB; + pCsr->isEof = 1; + } + } + } + } + + if( rc!=SQLITE_OK && pContext ){ + sqlite3_result_error_code(pContext, rc); + } + return rc; +} + +/* +** This function is used to process a single interior node when searching +** a b-tree for a term or term prefix. The node data is passed to this +** function via the zNode/nNode parameters. The term to search for is +** passed in zTerm/nTerm. +** +** If piFirst is not NULL, then this function sets *piFirst to the blockid +** of the child node that heads the sub-tree that may contain the term. +** +** If piLast is not NULL, then *piLast is set to the right-most child node +** that heads a sub-tree that may contain a term for which zTerm/nTerm is +** a prefix. +** +** If an OOM error occurs, SQLITE_NOMEM is returned. Otherwise, SQLITE_OK. +*/ +static int fts3ScanInteriorNode( + const char *zTerm, /* Term to select leaves for */ + int nTerm, /* Size of term zTerm in bytes */ + const char *zNode, /* Buffer containing segment interior node */ + int nNode, /* Size of buffer at zNode */ + sqlite3_int64 *piFirst, /* OUT: Selected child node */ + sqlite3_int64 *piLast /* OUT: Selected child node */ +){ + int rc = SQLITE_OK; /* Return code */ + const char *zCsr = zNode; /* Cursor to iterate through node */ + const char *zEnd = &zCsr[nNode];/* End of interior node buffer */ + char *zBuffer = 0; /* Buffer to load terms into */ + i64 nAlloc = 0; /* Size of allocated buffer */ + int isFirstTerm = 1; /* True when processing first term on page */ + u64 iChild; /* Block id of child node to descend to */ + int nBuffer = 0; /* Total term size */ + + /* Skip over the 'height' varint that occurs at the start of every + ** interior node. Then load the blockid of the left-child of the b-tree + ** node into variable iChild. + ** + ** Even if the data structure on disk is corrupted, this (reading two + ** varints from the buffer) does not risk an overread. If zNode is a + ** root node, then the buffer comes from a SELECT statement. SQLite does + ** not make this guarantee explicitly, but in practice there are always + ** either more than 20 bytes of allocated space following the nNode bytes of + ** contents, or two zero bytes. Or, if the node is read from the %_segments + ** table, then there are always 20 bytes of zeroed padding following the + ** nNode bytes of content (see sqlite3Fts3ReadBlock() for details). + */ + zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild); + zCsr += sqlite3Fts3GetVarintU(zCsr, &iChild); + if( zCsr>zEnd ){ + return FTS_CORRUPT_VTAB; + } + + while( zCsr<zEnd && (piFirst || piLast) ){ + int cmp; /* memcmp() result */ + int nSuffix; /* Size of term suffix */ + int nPrefix = 0; /* Size of term prefix */ + + /* Load the next term on the node into zBuffer. Use realloc() to expand + ** the size of zBuffer if required. */ + if( !isFirstTerm ){ + zCsr += fts3GetVarint32(zCsr, &nPrefix); + if( nPrefix>nBuffer ){ + rc = FTS_CORRUPT_VTAB; + goto finish_scan; + } + } + isFirstTerm = 0; + zCsr += fts3GetVarint32(zCsr, &nSuffix); + + assert( nPrefix>=0 && nSuffix>=0 ); + if( nPrefix>zCsr-zNode || nSuffix>zEnd-zCsr || nSuffix==0 ){ + rc = FTS_CORRUPT_VTAB; + goto finish_scan; + } + if( (i64)nPrefix+nSuffix>nAlloc ){ + char *zNew; + nAlloc = ((i64)nPrefix+nSuffix) * 2; + zNew = (char *)sqlite3_realloc64(zBuffer, nAlloc); + if( !zNew ){ + rc = SQLITE_NOMEM; + goto finish_scan; + } + zBuffer = zNew; + } + assert( zBuffer ); + memcpy(&zBuffer[nPrefix], zCsr, nSuffix); + nBuffer = nPrefix + nSuffix; + zCsr += nSuffix; + + /* Compare the term we are searching for with the term just loaded from + ** the interior node. If the specified term is greater than or equal + ** to the term from the interior node, then all terms on the sub-tree + ** headed by node iChild are smaller than zTerm. No need to search + ** iChild. + ** + ** If the interior node term is larger than the specified term, then + ** the tree headed by iChild may contain the specified term. + */ + cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer)); + if( piFirst && (cmp<0 || (cmp==0 && nBuffer>nTerm)) ){ + *piFirst = (i64)iChild; + piFirst = 0; + } + + if( piLast && cmp<0 ){ + *piLast = (i64)iChild; + piLast = 0; + } + + iChild++; + }; + + if( piFirst ) *piFirst = (i64)iChild; + if( piLast ) *piLast = (i64)iChild; + + finish_scan: + sqlite3_free(zBuffer); + return rc; +} + + +/* +** The buffer pointed to by argument zNode (size nNode bytes) contains an +** interior node of a b-tree segment. The zTerm buffer (size nTerm bytes) +** contains a term. This function searches the sub-tree headed by the zNode +** node for the range of leaf nodes that may contain the specified term +** or terms for which the specified term is a prefix. +** +** If piLeaf is not NULL, then *piLeaf is set to the blockid of the +** left-most leaf node in the tree that may contain the specified term. +** If piLeaf2 is not NULL, then *piLeaf2 is set to the blockid of the +** right-most leaf node that may contain a term for which the specified +** term is a prefix. +** +** It is possible that the range of returned leaf nodes does not contain +** the specified term or any terms for which it is a prefix. However, if the +** segment does contain any such terms, they are stored within the identified +** range. Because this function only inspects interior segment nodes (and +** never loads leaf nodes into memory), it is not possible to be sure. +** +** If an error occurs, an error code other than SQLITE_OK is returned. +*/ +static int fts3SelectLeaf( + Fts3Table *p, /* Virtual table handle */ + const char *zTerm, /* Term to select leaves for */ + int nTerm, /* Size of term zTerm in bytes */ + const char *zNode, /* Buffer containing segment interior node */ + int nNode, /* Size of buffer at zNode */ + sqlite3_int64 *piLeaf, /* Selected leaf node */ + sqlite3_int64 *piLeaf2 /* Selected leaf node */ +){ + int rc = SQLITE_OK; /* Return code */ + int iHeight; /* Height of this node in tree */ + + assert( piLeaf || piLeaf2 ); + + fts3GetVarint32(zNode, &iHeight); + rc = fts3ScanInteriorNode(zTerm, nTerm, zNode, nNode, piLeaf, piLeaf2); + assert_fts3_nc( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) ); + + if( rc==SQLITE_OK && iHeight>1 ){ + char *zBlob = 0; /* Blob read from %_segments table */ + int nBlob = 0; /* Size of zBlob in bytes */ + + if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){ + rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob, 0); + if( rc==SQLITE_OK ){ + rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0); + } + sqlite3_free(zBlob); + piLeaf = 0; + zBlob = 0; + } + + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3ReadBlock(p, piLeaf?*piLeaf:*piLeaf2, &zBlob, &nBlob, 0); + } + if( rc==SQLITE_OK ){ + int iNewHeight = 0; + fts3GetVarint32(zBlob, &iNewHeight); + if( iNewHeight>=iHeight ){ + rc = FTS_CORRUPT_VTAB; + }else{ + rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2); + } + } + sqlite3_free(zBlob); + } + + return rc; +} + +/* +** This function is used to create delta-encoded serialized lists of FTS3 +** varints. Each call to this function appends a single varint to a list. +*/ +static void fts3PutDeltaVarint( + char **pp, /* IN/OUT: Output pointer */ + sqlite3_int64 *piPrev, /* IN/OUT: Previous value written to list */ + sqlite3_int64 iVal /* Write this value to the list */ +){ + assert_fts3_nc( iVal-*piPrev > 0 || (*piPrev==0 && iVal==0) ); + *pp += sqlite3Fts3PutVarint(*pp, iVal-*piPrev); + *piPrev = iVal; +} + +/* +** When this function is called, *ppPoslist is assumed to point to the +** start of a position-list. After it returns, *ppPoslist points to the +** first byte after the position-list. +** +** A position list is list of positions (delta encoded) and columns for +** a single document record of a doclist. So, in other words, this +** routine advances *ppPoslist so that it points to the next docid in +** the doclist, or to the first byte past the end of the doclist. +** +** If pp is not NULL, then the contents of the position list are copied +** to *pp. *pp is set to point to the first byte past the last byte copied +** before this function returns. +*/ +static void fts3PoslistCopy(char **pp, char **ppPoslist){ + char *pEnd = *ppPoslist; + char c = 0; + + /* The end of a position list is marked by a zero encoded as an FTS3 + ** varint. A single POS_END (0) byte. Except, if the 0 byte is preceded by + ** a byte with the 0x80 bit set, then it is not a varint 0, but the tail + ** of some other, multi-byte, value. + ** + ** The following while-loop moves pEnd to point to the first byte that is not + ** immediately preceded by a byte with the 0x80 bit set. Then increments + ** pEnd once more so that it points to the byte immediately following the + ** last byte in the position-list. + */ + while( *pEnd | c ){ + c = *pEnd++ & 0x80; + testcase( c!=0 && (*pEnd)==0 ); + } + pEnd++; /* Advance past the POS_END terminator byte */ + + if( pp ){ + int n = (int)(pEnd - *ppPoslist); + char *p = *pp; + memcpy(p, *ppPoslist, n); + p += n; + *pp = p; + } + *ppPoslist = pEnd; +} + +/* +** When this function is called, *ppPoslist is assumed to point to the +** start of a column-list. After it returns, *ppPoslist points to the +** to the terminator (POS_COLUMN or POS_END) byte of the column-list. +** +** A column-list is list of delta-encoded positions for a single column +** within a single document within a doclist. +** +** The column-list is terminated either by a POS_COLUMN varint (1) or +** a POS_END varint (0). This routine leaves *ppPoslist pointing to +** the POS_COLUMN or POS_END that terminates the column-list. +** +** If pp is not NULL, then the contents of the column-list are copied +** to *pp. *pp is set to point to the first byte past the last byte copied +** before this function returns. The POS_COLUMN or POS_END terminator +** is not copied into *pp. +*/ +static void fts3ColumnlistCopy(char **pp, char **ppPoslist){ + char *pEnd = *ppPoslist; + char c = 0; + + /* A column-list is terminated by either a 0x01 or 0x00 byte that is + ** not part of a multi-byte varint. + */ + while( 0xFE & (*pEnd | c) ){ + c = *pEnd++ & 0x80; + testcase( c!=0 && ((*pEnd)&0xfe)==0 ); + } + if( pp ){ + int n = (int)(pEnd - *ppPoslist); + char *p = *pp; + memcpy(p, *ppPoslist, n); + p += n; + *pp = p; + } + *ppPoslist = pEnd; +} + +/* +** Value used to signify the end of an position-list. This must be +** as large or larger than any value that might appear on the +** position-list, even a position list that has been corrupted. +*/ +#define POSITION_LIST_END LARGEST_INT64 + +/* +** This function is used to help parse position-lists. When this function is +** called, *pp may point to the start of the next varint in the position-list +** being parsed, or it may point to 1 byte past the end of the position-list +** (in which case **pp will be a terminator bytes POS_END (0) or +** (1)). +** +** If *pp points past the end of the current position-list, set *pi to +** POSITION_LIST_END and return. Otherwise, read the next varint from *pp, +** increment the current value of *pi by the value read, and set *pp to +** point to the next value before returning. +** +** Before calling this routine *pi must be initialized to the value of +** the previous position, or zero if we are reading the first position +** in the position-list. Because positions are delta-encoded, the value +** of the previous position is needed in order to compute the value of +** the next position. +*/ +static void fts3ReadNextPos( + char **pp, /* IN/OUT: Pointer into position-list buffer */ + sqlite3_int64 *pi /* IN/OUT: Value read from position-list */ +){ + if( (**pp)&0xFE ){ + int iVal; + *pp += fts3GetVarint32((*pp), &iVal); + *pi += iVal; + *pi -= 2; + }else{ + *pi = POSITION_LIST_END; + } +} + +/* +** If parameter iCol is not 0, write an POS_COLUMN (1) byte followed by +** the value of iCol encoded as a varint to *pp. This will start a new +** column list. +** +** Set *pp to point to the byte just after the last byte written before +** returning (do not modify it if iCol==0). Return the total number of bytes +** written (0 if iCol==0). +*/ +static int fts3PutColNumber(char **pp, int iCol){ + int n = 0; /* Number of bytes written */ + if( iCol ){ + char *p = *pp; /* Output pointer */ + n = 1 + sqlite3Fts3PutVarint(&p[1], iCol); + *p = 0x01; + *pp = &p[n]; + } + return n; +} + +/* +** Compute the union of two position lists. The output written +** into *pp contains all positions of both *pp1 and *pp2 in sorted +** order and with any duplicates removed. All pointers are +** updated appropriately. The caller is responsible for insuring +** that there is enough space in *pp to hold the complete output. +*/ +static int fts3PoslistMerge( + char **pp, /* Output buffer */ + char **pp1, /* Left input list */ + char **pp2 /* Right input list */ +){ + char *p = *pp; + char *p1 = *pp1; + char *p2 = *pp2; + + while( *p1 || *p2 ){ + int iCol1; /* The current column index in pp1 */ + int iCol2; /* The current column index in pp2 */ + + if( *p1==POS_COLUMN ){ + fts3GetVarint32(&p1[1], &iCol1); + if( iCol1==0 ) return FTS_CORRUPT_VTAB; + } + else if( *p1==POS_END ) iCol1 = 0x7fffffff; + else iCol1 = 0; + + if( *p2==POS_COLUMN ){ + fts3GetVarint32(&p2[1], &iCol2); + if( iCol2==0 ) return FTS_CORRUPT_VTAB; + } + else if( *p2==POS_END ) iCol2 = 0x7fffffff; + else iCol2 = 0; + + if( iCol1==iCol2 ){ + sqlite3_int64 i1 = 0; /* Last position from pp1 */ + sqlite3_int64 i2 = 0; /* Last position from pp2 */ + sqlite3_int64 iPrev = 0; + int n = fts3PutColNumber(&p, iCol1); + p1 += n; + p2 += n; + + /* At this point, both p1 and p2 point to the start of column-lists + ** for the same column (the column with index iCol1 and iCol2). + ** A column-list is a list of non-negative delta-encoded varints, each + ** incremented by 2 before being stored. Each list is terminated by a + ** POS_END (0) or POS_COLUMN (1). The following block merges the two lists + ** and writes the results to buffer p. p is left pointing to the byte + ** after the list written. No terminator (POS_END or POS_COLUMN) is + ** written to the output. + */ + fts3GetDeltaVarint(&p1, &i1); + fts3GetDeltaVarint(&p2, &i2); + if( i1<2 || i2<2 ){ + break; + } + do { + fts3PutDeltaVarint(&p, &iPrev, (i1<i2) ? i1 : i2); + iPrev -= 2; + if( i1==i2 ){ + fts3ReadNextPos(&p1, &i1); + fts3ReadNextPos(&p2, &i2); + }else if( i1<i2 ){ + fts3ReadNextPos(&p1, &i1); + }else{ + fts3ReadNextPos(&p2, &i2); + } + }while( i1!=POSITION_LIST_END || i2!=POSITION_LIST_END ); + }else if( iCol1<iCol2 ){ + p1 += fts3PutColNumber(&p, iCol1); + fts3ColumnlistCopy(&p, &p1); + }else{ + p2 += fts3PutColNumber(&p, iCol2); + fts3ColumnlistCopy(&p, &p2); + } + } + + *p++ = POS_END; + *pp = p; + *pp1 = p1 + 1; + *pp2 = p2 + 1; + return SQLITE_OK; +} + +/* +** This function is used to merge two position lists into one. When it is +** called, *pp1 and *pp2 must both point to position lists. A position-list is +** the part of a doclist that follows each document id. For example, if a row +** contains: +** +** 'a b c'|'x y z'|'a b b a' +** +** Then the position list for this row for token 'b' would consist of: +** +** 0x02 0x01 0x02 0x03 0x03 0x00 +** +** When this function returns, both *pp1 and *pp2 are left pointing to the +** byte following the 0x00 terminator of their respective position lists. +** +** If isSaveLeft is 0, an entry is added to the output position list for +** each position in *pp2 for which there exists one or more positions in +** *pp1 so that (pos(*pp2)>pos(*pp1) && pos(*pp2)-pos(*pp1)<=nToken). i.e. +** when the *pp1 token appears before the *pp2 token, but not more than nToken +** slots before it. +** +** e.g. nToken==1 searches for adjacent positions. +*/ +static int fts3PoslistPhraseMerge( + char **pp, /* IN/OUT: Preallocated output buffer */ + int nToken, /* Maximum difference in token positions */ + int isSaveLeft, /* Save the left position */ + int isExact, /* If *pp1 is exactly nTokens before *pp2 */ + char **pp1, /* IN/OUT: Left input list */ + char **pp2 /* IN/OUT: Right input list */ +){ + char *p = *pp; + char *p1 = *pp1; + char *p2 = *pp2; + int iCol1 = 0; + int iCol2 = 0; + + /* Never set both isSaveLeft and isExact for the same invocation. */ + assert( isSaveLeft==0 || isExact==0 ); + + assert_fts3_nc( p!=0 && *p1!=0 && *p2!=0 ); + if( *p1==POS_COLUMN ){ + p1++; + p1 += fts3GetVarint32(p1, &iCol1); + } + if( *p2==POS_COLUMN ){ + p2++; + p2 += fts3GetVarint32(p2, &iCol2); + } + + while( 1 ){ + if( iCol1==iCol2 ){ + char *pSave = p; + sqlite3_int64 iPrev = 0; + sqlite3_int64 iPos1 = 0; + sqlite3_int64 iPos2 = 0; + + if( iCol1 ){ + *p++ = POS_COLUMN; + p += sqlite3Fts3PutVarint(p, iCol1); + } + + fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2; + fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2; + if( iPos1<0 || iPos2<0 ) break; + + while( 1 ){ + if( iPos2==iPos1+nToken + || (isExact==0 && iPos2>iPos1 && iPos2<=iPos1+nToken) + ){ + sqlite3_int64 iSave; + iSave = isSaveLeft ? iPos1 : iPos2; + fts3PutDeltaVarint(&p, &iPrev, iSave+2); iPrev -= 2; + pSave = 0; + assert( p ); + } + if( (!isSaveLeft && iPos2<=(iPos1+nToken)) || iPos2<=iPos1 ){ + if( (*p2&0xFE)==0 ) break; + fts3GetDeltaVarint(&p2, &iPos2); iPos2 -= 2; + }else{ + if( (*p1&0xFE)==0 ) break; + fts3GetDeltaVarint(&p1, &iPos1); iPos1 -= 2; + } + } + + if( pSave ){ + assert( pp && p ); + p = pSave; + } + + fts3ColumnlistCopy(0, &p1); + fts3ColumnlistCopy(0, &p2); + assert( (*p1&0xFE)==0 && (*p2&0xFE)==0 ); + if( 0==*p1 || 0==*p2 ) break; + + p1++; + p1 += fts3GetVarint32(p1, &iCol1); + p2++; + p2 += fts3GetVarint32(p2, &iCol2); + } + + /* Advance pointer p1 or p2 (whichever corresponds to the smaller of + ** iCol1 and iCol2) so that it points to either the 0x00 that marks the + ** end of the position list, or the 0x01 that precedes the next + ** column-number in the position list. + */ + else if( iCol1<iCol2 ){ + fts3ColumnlistCopy(0, &p1); + if( 0==*p1 ) break; + p1++; + p1 += fts3GetVarint32(p1, &iCol1); + }else{ + fts3ColumnlistCopy(0, &p2); + if( 0==*p2 ) break; + p2++; + p2 += fts3GetVarint32(p2, &iCol2); + } + } + + fts3PoslistCopy(0, &p2); + fts3PoslistCopy(0, &p1); + *pp1 = p1; + *pp2 = p2; + if( *pp==p ){ + return 0; + } + *p++ = 0x00; + *pp = p; + return 1; +} + +/* +** Merge two position-lists as required by the NEAR operator. The argument +** position lists correspond to the left and right phrases of an expression +** like: +** +** "phrase 1" NEAR "phrase number 2" +** +** Position list *pp1 corresponds to the left-hand side of the NEAR +** expression and *pp2 to the right. As usual, the indexes in the position +** lists are the offsets of the last token in each phrase (tokens "1" and "2" +** in the example above). +** +** The output position list - written to *pp - is a copy of *pp2 with those +** entries that are not sufficiently NEAR entries in *pp1 removed. +*/ +static int fts3PoslistNearMerge( + char **pp, /* Output buffer */ + char *aTmp, /* Temporary buffer space */ + int nRight, /* Maximum difference in token positions */ + int nLeft, /* Maximum difference in token positions */ + char **pp1, /* IN/OUT: Left input list */ + char **pp2 /* IN/OUT: Right input list */ +){ + char *p1 = *pp1; + char *p2 = *pp2; + + char *pTmp1 = aTmp; + char *pTmp2; + char *aTmp2; + int res = 1; + + fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2); + aTmp2 = pTmp2 = pTmp1; + *pp1 = p1; + *pp2 = p2; + fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1); + if( pTmp1!=aTmp && pTmp2!=aTmp2 ){ + fts3PoslistMerge(pp, &aTmp, &aTmp2); + }else if( pTmp1!=aTmp ){ + fts3PoslistCopy(pp, &aTmp); + }else if( pTmp2!=aTmp2 ){ + fts3PoslistCopy(pp, &aTmp2); + }else{ + res = 0; + } + + return res; +} + +/* +** An instance of this function is used to merge together the (potentially +** large number of) doclists for each term that matches a prefix query. +** See function fts3TermSelectMerge() for details. +*/ +typedef struct TermSelect TermSelect; +struct TermSelect { + char *aaOutput[16]; /* Malloc'd output buffers */ + int anOutput[16]; /* Size each output buffer in bytes */ +}; + +/* +** This function is used to read a single varint from a buffer. Parameter +** pEnd points 1 byte past the end of the buffer. When this function is +** called, if *pp points to pEnd or greater, then the end of the buffer +** has been reached. In this case *pp is set to 0 and the function returns. +** +** If *pp does not point to or past pEnd, then a single varint is read +** from *pp. *pp is then set to point 1 byte past the end of the read varint. +** +** If bDescIdx is false, the value read is added to *pVal before returning. +** If it is true, the value read is subtracted from *pVal before this +** function returns. +*/ +static void fts3GetDeltaVarint3( + char **pp, /* IN/OUT: Point to read varint from */ + char *pEnd, /* End of buffer */ + int bDescIdx, /* True if docids are descending */ + sqlite3_int64 *pVal /* IN/OUT: Integer value */ +){ + if( *pp>=pEnd ){ + *pp = 0; + }else{ + u64 iVal; + *pp += sqlite3Fts3GetVarintU(*pp, &iVal); + if( bDescIdx ){ + *pVal = (i64)((u64)*pVal - iVal); + }else{ + *pVal = (i64)((u64)*pVal + iVal); + } + } +} + +/* +** This function is used to write a single varint to a buffer. The varint +** is written to *pp. Before returning, *pp is set to point 1 byte past the +** end of the value written. +** +** If *pbFirst is zero when this function is called, the value written to +** the buffer is that of parameter iVal. +** +** If *pbFirst is non-zero when this function is called, then the value +** written is either (iVal-*piPrev) (if bDescIdx is zero) or (*piPrev-iVal) +** (if bDescIdx is non-zero). +** +** Before returning, this function always sets *pbFirst to 1 and *piPrev +** to the value of parameter iVal. +*/ +static void fts3PutDeltaVarint3( + char **pp, /* IN/OUT: Output pointer */ + int bDescIdx, /* True for descending docids */ + sqlite3_int64 *piPrev, /* IN/OUT: Previous value written to list */ + int *pbFirst, /* IN/OUT: True after first int written */ + sqlite3_int64 iVal /* Write this value to the list */ +){ + sqlite3_uint64 iWrite; + if( bDescIdx==0 || *pbFirst==0 ){ + assert_fts3_nc( *pbFirst==0 || iVal>=*piPrev ); + iWrite = (u64)iVal - (u64)*piPrev; + }else{ + assert_fts3_nc( *piPrev>=iVal ); + iWrite = (u64)*piPrev - (u64)iVal; + } + assert( *pbFirst || *piPrev==0 ); + assert_fts3_nc( *pbFirst==0 || iWrite>0 ); + *pp += sqlite3Fts3PutVarint(*pp, iWrite); + *piPrev = iVal; + *pbFirst = 1; +} + + +/* +** This macro is used by various functions that merge doclists. The two +** arguments are 64-bit docid values. If the value of the stack variable +** bDescDoclist is 0 when this macro is invoked, then it returns (i1-i2). +** Otherwise, (i2-i1). +** +** Using this makes it easier to write code that can merge doclists that are +** sorted in either ascending or descending order. +*/ +/* #define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i64)((u64)i1-i2)) */ +#define DOCID_CMP(i1, i2) ((bDescDoclist?-1:1) * (i1>i2?1:((i1==i2)?0:-1))) + +/* +** This function does an "OR" merge of two doclists (output contains all +** positions contained in either argument doclist). If the docids in the +** input doclists are sorted in ascending order, parameter bDescDoclist +** should be false. If they are sorted in ascending order, it should be +** passed a non-zero value. +** +** If no error occurs, *paOut is set to point at an sqlite3_malloc'd buffer +** containing the output doclist and SQLITE_OK is returned. In this case +** *pnOut is set to the number of bytes in the output doclist. +** +** If an error occurs, an SQLite error code is returned. The output values +** are undefined in this case. +*/ +static int fts3DoclistOrMerge( + int bDescDoclist, /* True if arguments are desc */ + char *a1, int n1, /* First doclist */ + char *a2, int n2, /* Second doclist */ + char **paOut, int *pnOut /* OUT: Malloc'd doclist */ +){ + int rc = SQLITE_OK; + sqlite3_int64 i1 = 0; + sqlite3_int64 i2 = 0; + sqlite3_int64 iPrev = 0; + char *pEnd1 = &a1[n1]; + char *pEnd2 = &a2[n2]; + char *p1 = a1; + char *p2 = a2; + char *p; + char *aOut; + int bFirstOut = 0; + + *paOut = 0; + *pnOut = 0; + + /* Allocate space for the output. Both the input and output doclists + ** are delta encoded. If they are in ascending order (bDescDoclist==0), + ** then the first docid in each list is simply encoded as a varint. For + ** each subsequent docid, the varint stored is the difference between the + ** current and previous docid (a positive number - since the list is in + ** ascending order). + ** + ** The first docid written to the output is therefore encoded using the + ** same number of bytes as it is in whichever of the input lists it is + ** read from. And each subsequent docid read from the same input list + ** consumes either the same or less bytes as it did in the input (since + ** the difference between it and the previous value in the output must + ** be a positive value less than or equal to the delta value read from + ** the input list). The same argument applies to all but the first docid + ** read from the 'other' list. And to the contents of all position lists + ** that will be copied and merged from the input to the output. + ** + ** However, if the first docid copied to the output is a negative number, + ** then the encoding of the first docid from the 'other' input list may + ** be larger in the output than it was in the input (since the delta value + ** may be a larger positive integer than the actual docid). + ** + ** The space required to store the output is therefore the sum of the + ** sizes of the two inputs, plus enough space for exactly one of the input + ** docids to grow. + ** + ** A symetric argument may be made if the doclists are in descending + ** order. + */ + aOut = sqlite3_malloc64((i64)n1+n2+FTS3_VARINT_MAX-1+FTS3_BUFFER_PADDING); + if( !aOut ) return SQLITE_NOMEM; + + p = aOut; + fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1); + fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2); + while( p1 || p2 ){ + sqlite3_int64 iDiff = DOCID_CMP(i1, i2); + + if( p2 && p1 && iDiff==0 ){ + fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1); + rc = fts3PoslistMerge(&p, &p1, &p2); + if( rc ) break; + fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1); + fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2); + }else if( !p2 || (p1 && iDiff<0) ){ + fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1); + fts3PoslistCopy(&p, &p1); + fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1); + }else{ + fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i2); + fts3PoslistCopy(&p, &p2); + fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2); + } + + assert( (p-aOut)<=((p1?(p1-a1):n1)+(p2?(p2-a2):n2)+FTS3_VARINT_MAX-1) ); + } + + if( rc!=SQLITE_OK ){ + sqlite3_free(aOut); + p = aOut = 0; + }else{ + assert( (p-aOut)<=n1+n2+FTS3_VARINT_MAX-1 ); + memset(&aOut[(p-aOut)], 0, FTS3_BUFFER_PADDING); + } + *paOut = aOut; + *pnOut = (int)(p-aOut); + return rc; +} + +/* +** This function does a "phrase" merge of two doclists. In a phrase merge, +** the output contains a copy of each position from the right-hand input +** doclist for which there is a position in the left-hand input doclist +** exactly nDist tokens before it. +** +** If the docids in the input doclists are sorted in ascending order, +** parameter bDescDoclist should be false. If they are sorted in ascending +** order, it should be passed a non-zero value. +** +** The right-hand input doclist is overwritten by this function. +*/ +static int fts3DoclistPhraseMerge( + int bDescDoclist, /* True if arguments are desc */ + int nDist, /* Distance from left to right (1=adjacent) */ + char *aLeft, int nLeft, /* Left doclist */ + char **paRight, int *pnRight /* IN/OUT: Right/output doclist */ +){ + sqlite3_int64 i1 = 0; + sqlite3_int64 i2 = 0; + sqlite3_int64 iPrev = 0; + char *aRight = *paRight; + char *pEnd1 = &aLeft[nLeft]; + char *pEnd2 = &aRight[*pnRight]; + char *p1 = aLeft; + char *p2 = aRight; + char *p; + int bFirstOut = 0; + char *aOut; + + assert( nDist>0 ); + if( bDescDoclist ){ + aOut = sqlite3_malloc64((sqlite3_int64)*pnRight + FTS3_VARINT_MAX); + if( aOut==0 ) return SQLITE_NOMEM; + }else{ + aOut = aRight; + } + p = aOut; + + fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1); + fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2); + + while( p1 && p2 ){ + sqlite3_int64 iDiff = DOCID_CMP(i1, i2); + if( iDiff==0 ){ + char *pSave = p; + sqlite3_int64 iPrevSave = iPrev; + int bFirstOutSave = bFirstOut; + + fts3PutDeltaVarint3(&p, bDescDoclist, &iPrev, &bFirstOut, i1); + if( 0==fts3PoslistPhraseMerge(&p, nDist, 0, 1, &p1, &p2) ){ + p = pSave; + iPrev = iPrevSave; + bFirstOut = bFirstOutSave; + } + fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1); + fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2); + }else if( iDiff<0 ){ + fts3PoslistCopy(0, &p1); + fts3GetDeltaVarint3(&p1, pEnd1, bDescDoclist, &i1); + }else{ + fts3PoslistCopy(0, &p2); + fts3GetDeltaVarint3(&p2, pEnd2, bDescDoclist, &i2); + } + } + + *pnRight = (int)(p - aOut); + if( bDescDoclist ){ + sqlite3_free(aRight); + *paRight = aOut; + } + + return SQLITE_OK; +} + +/* +** Argument pList points to a position list nList bytes in size. This +** function checks to see if the position list contains any entries for +** a token in position 0 (of any column). If so, it writes argument iDelta +** to the output buffer pOut, followed by a position list consisting only +** of the entries from pList at position 0, and terminated by an 0x00 byte. +** The value returned is the number of bytes written to pOut (if any). +*/ +int sqlite3Fts3FirstFilter( + sqlite3_int64 iDelta, /* Varint that may be written to pOut */ + char *pList, /* Position list (no 0x00 term) */ + int nList, /* Size of pList in bytes */ + char *pOut /* Write output here */ +){ + int nOut = 0; + int bWritten = 0; /* True once iDelta has been written */ + char *p = pList; + char *pEnd = &pList[nList]; + + if( *p!=0x01 ){ + if( *p==0x02 ){ + nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta); + pOut[nOut++] = 0x02; + bWritten = 1; + } + fts3ColumnlistCopy(0, &p); + } + + while( p<pEnd ){ + sqlite3_int64 iCol; + p++; + p += sqlite3Fts3GetVarint(p, &iCol); + if( *p==0x02 ){ + if( bWritten==0 ){ + nOut += sqlite3Fts3PutVarint(&pOut[nOut], iDelta); + bWritten = 1; + } + pOut[nOut++] = 0x01; + nOut += sqlite3Fts3PutVarint(&pOut[nOut], iCol); + pOut[nOut++] = 0x02; + } + fts3ColumnlistCopy(0, &p); + } + if( bWritten ){ + pOut[nOut++] = 0x00; + } + + return nOut; +} + + +/* +** Merge all doclists in the TermSelect.aaOutput[] array into a single +** doclist stored in TermSelect.aaOutput[0]. If successful, delete all +** other doclists (except the aaOutput[0] one) and return SQLITE_OK. +** +** If an OOM error occurs, return SQLITE_NOMEM. In this case it is +** the responsibility of the caller to free any doclists left in the +** TermSelect.aaOutput[] array. +*/ +static int fts3TermSelectFinishMerge(Fts3Table *p, TermSelect *pTS){ + char *aOut = 0; + int nOut = 0; + int i; + + /* Loop through the doclists in the aaOutput[] array. Merge them all + ** into a single doclist. + */ + for(i=0; i<SizeofArray(pTS->aaOutput); i++){ + if( pTS->aaOutput[i] ){ + if( !aOut ){ + aOut = pTS->aaOutput[i]; + nOut = pTS->anOutput[i]; + pTS->aaOutput[i] = 0; + }else{ + int nNew; + char *aNew; + + int rc = fts3DoclistOrMerge(p->bDescIdx, + pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, &aNew, &nNew + ); + if( rc!=SQLITE_OK ){ + sqlite3_free(aOut); + return rc; + } + + sqlite3_free(pTS->aaOutput[i]); + sqlite3_free(aOut); + pTS->aaOutput[i] = 0; + aOut = aNew; + nOut = nNew; + } + } + } + + pTS->aaOutput[0] = aOut; + pTS->anOutput[0] = nOut; + return SQLITE_OK; +} + +/* +** Merge the doclist aDoclist/nDoclist into the TermSelect object passed +** as the first argument. The merge is an "OR" merge (see function +** fts3DoclistOrMerge() for details). +** +** This function is called with the doclist for each term that matches +** a queried prefix. It merges all these doclists into one, the doclist +** for the specified prefix. Since there can be a very large number of +** doclists to merge, the merging is done pair-wise using the TermSelect +** object. +** +** This function returns SQLITE_OK if the merge is successful, or an +** SQLite error code (SQLITE_NOMEM) if an error occurs. +*/ +static int fts3TermSelectMerge( + Fts3Table *p, /* FTS table handle */ + TermSelect *pTS, /* TermSelect object to merge into */ + char *aDoclist, /* Pointer to doclist */ + int nDoclist /* Size of aDoclist in bytes */ +){ + if( pTS->aaOutput[0]==0 ){ + /* If this is the first term selected, copy the doclist to the output + ** buffer using memcpy(). + ** + ** Add FTS3_VARINT_MAX bytes of unused space to the end of the + ** allocation. This is so as to ensure that the buffer is big enough + ** to hold the current doclist AND'd with any other doclist. If the + ** doclists are stored in order=ASC order, this padding would not be + ** required (since the size of [doclistA AND doclistB] is always less + ** than or equal to the size of [doclistA] in that case). But this is + ** not true for order=DESC. For example, a doclist containing (1, -1) + ** may be smaller than (-1), as in the first example the -1 may be stored + ** as a single-byte delta, whereas in the second it must be stored as a + ** FTS3_VARINT_MAX byte varint. + ** + ** Similar padding is added in the fts3DoclistOrMerge() function. + */ + pTS->aaOutput[0] = sqlite3_malloc64((i64)nDoclist + FTS3_VARINT_MAX + 1); + pTS->anOutput[0] = nDoclist; + if( pTS->aaOutput[0] ){ + memcpy(pTS->aaOutput[0], aDoclist, nDoclist); + memset(&pTS->aaOutput[0][nDoclist], 0, FTS3_VARINT_MAX); + }else{ + return SQLITE_NOMEM; + } + }else{ + char *aMerge = aDoclist; + int nMerge = nDoclist; + int iOut; + + for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){ + if( pTS->aaOutput[iOut]==0 ){ + assert( iOut>0 ); + pTS->aaOutput[iOut] = aMerge; + pTS->anOutput[iOut] = nMerge; + break; + }else{ + char *aNew; + int nNew; + + int rc = fts3DoclistOrMerge(p->bDescIdx, aMerge, nMerge, + pTS->aaOutput[iOut], pTS->anOutput[iOut], &aNew, &nNew + ); + if( rc!=SQLITE_OK ){ + if( aMerge!=aDoclist ) sqlite3_free(aMerge); + return rc; + } + + if( aMerge!=aDoclist ) sqlite3_free(aMerge); + sqlite3_free(pTS->aaOutput[iOut]); + pTS->aaOutput[iOut] = 0; + + aMerge = aNew; + nMerge = nNew; + if( (iOut+1)==SizeofArray(pTS->aaOutput) ){ + pTS->aaOutput[iOut] = aMerge; + pTS->anOutput[iOut] = nMerge; + } + } + } + } + return SQLITE_OK; +} + +/* +** Append SegReader object pNew to the end of the pCsr->apSegment[] array. +*/ +static int fts3SegReaderCursorAppend( + Fts3MultiSegReader *pCsr, + Fts3SegReader *pNew +){ + if( (pCsr->nSegment%16)==0 ){ + Fts3SegReader **apNew; + sqlite3_int64 nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*); + apNew = (Fts3SegReader **)sqlite3_realloc64(pCsr->apSegment, nByte); + if( !apNew ){ + sqlite3Fts3SegReaderFree(pNew); + return SQLITE_NOMEM; + } + pCsr->apSegment = apNew; + } + pCsr->apSegment[pCsr->nSegment++] = pNew; + return SQLITE_OK; +} + +/* +** Add seg-reader objects to the Fts3MultiSegReader object passed as the +** 8th argument. +** +** This function returns SQLITE_OK if successful, or an SQLite error code +** otherwise. +*/ +static int fts3SegReaderCursor( + Fts3Table *p, /* FTS3 table handle */ + int iLangid, /* Language id */ + int iIndex, /* Index to search (from 0 to p->nIndex-1) */ + int iLevel, /* Level of segments to scan */ + const char *zTerm, /* Term to query for */ + int nTerm, /* Size of zTerm in bytes */ + int isPrefix, /* True for a prefix search */ + int isScan, /* True to scan from zTerm to EOF */ + Fts3MultiSegReader *pCsr /* Cursor object to populate */ +){ + int rc = SQLITE_OK; /* Error code */ + sqlite3_stmt *pStmt = 0; /* Statement to iterate through segments */ + int rc2; /* Result of sqlite3_reset() */ + + /* If iLevel is less than 0 and this is not a scan, include a seg-reader + ** for the pending-terms. If this is a scan, then this call must be being + ** made by an fts4aux module, not an FTS table. In this case calling + ** Fts3SegReaderPending might segfault, as the data structures used by + ** fts4aux are not completely populated. So it's easiest to filter these + ** calls out here. */ + if( iLevel<0 && p->aIndex && p->iPrevLangid==iLangid ){ + Fts3SegReader *pSeg = 0; + rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix||isScan, &pSeg); + if( rc==SQLITE_OK && pSeg ){ + rc = fts3SegReaderCursorAppend(pCsr, pSeg); + } + } + + if( iLevel!=FTS3_SEGCURSOR_PENDING ){ + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3AllSegdirs(p, iLangid, iIndex, iLevel, &pStmt); + } + + while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){ + Fts3SegReader *pSeg = 0; + + /* Read the values returned by the SELECT into local variables. */ + sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1); + sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2); + sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3); + int nRoot = sqlite3_column_bytes(pStmt, 4); + char const *zRoot = sqlite3_column_blob(pStmt, 4); + + /* If zTerm is not NULL, and this segment is not stored entirely on its + ** root node, the range of leaves scanned can be reduced. Do this. */ + if( iStartBlock && zTerm && zRoot ){ + sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0); + rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi); + if( rc!=SQLITE_OK ) goto finished; + if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock; + } + + rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1, + (isPrefix==0 && isScan==0), + iStartBlock, iLeavesEndBlock, + iEndBlock, zRoot, nRoot, &pSeg + ); + if( rc!=SQLITE_OK ) goto finished; + rc = fts3SegReaderCursorAppend(pCsr, pSeg); + } + } + + finished: + rc2 = sqlite3_reset(pStmt); + if( rc==SQLITE_DONE ) rc = rc2; + + return rc; +} + +/* +** Set up a cursor object for iterating through a full-text index or a +** single level therein. +*/ +int sqlite3Fts3SegReaderCursor( + Fts3Table *p, /* FTS3 table handle */ + int iLangid, /* Language-id to search */ + int iIndex, /* Index to search (from 0 to p->nIndex-1) */ + int iLevel, /* Level of segments to scan */ + const char *zTerm, /* Term to query for */ + int nTerm, /* Size of zTerm in bytes */ + int isPrefix, /* True for a prefix search */ + int isScan, /* True to scan from zTerm to EOF */ + Fts3MultiSegReader *pCsr /* Cursor object to populate */ +){ + assert( iIndex>=0 && iIndex<p->nIndex ); + assert( iLevel==FTS3_SEGCURSOR_ALL + || iLevel==FTS3_SEGCURSOR_PENDING + || iLevel>=0 + ); + assert( iLevel<FTS3_SEGDIR_MAXLEVEL ); + assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 ); + assert( isPrefix==0 || isScan==0 ); + + memset(pCsr, 0, sizeof(Fts3MultiSegReader)); + return fts3SegReaderCursor( + p, iLangid, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr + ); +} + +/* +** In addition to its current configuration, have the Fts3MultiSegReader +** passed as the 4th argument also scan the doclist for term zTerm/nTerm. +** +** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code. +*/ +static int fts3SegReaderCursorAddZero( + Fts3Table *p, /* FTS virtual table handle */ + int iLangid, + const char *zTerm, /* Term to scan doclist of */ + int nTerm, /* Number of bytes in zTerm */ + Fts3MultiSegReader *pCsr /* Fts3MultiSegReader to modify */ +){ + return fts3SegReaderCursor(p, + iLangid, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr + ); +} + +/* +** Open an Fts3MultiSegReader to scan the doclist for term zTerm/nTerm. Or, +** if isPrefix is true, to scan the doclist for all terms for which +** zTerm/nTerm is a prefix. If successful, return SQLITE_OK and write +** a pointer to the new Fts3MultiSegReader to *ppSegcsr. Otherwise, return +** an SQLite error code. +** +** It is the responsibility of the caller to free this object by eventually +** passing it to fts3SegReaderCursorFree() +** +** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code. +** Output parameter *ppSegcsr is set to 0 if an error occurs. +*/ +static int fts3TermSegReaderCursor( + Fts3Cursor *pCsr, /* Virtual table cursor handle */ + const char *zTerm, /* Term to query for */ + int nTerm, /* Size of zTerm in bytes */ + int isPrefix, /* True for a prefix search */ + Fts3MultiSegReader **ppSegcsr /* OUT: Allocated seg-reader cursor */ +){ + Fts3MultiSegReader *pSegcsr; /* Object to allocate and return */ + int rc = SQLITE_NOMEM; /* Return code */ + + pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader)); + if( pSegcsr ){ + int i; + int bFound = 0; /* True once an index has been found */ + Fts3Table *p = (Fts3Table *)pCsr->base.pVtab; + + if( isPrefix ){ + for(i=1; bFound==0 && i<p->nIndex; i++){ + if( p->aIndex[i].nPrefix==nTerm ){ + bFound = 1; + rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, + i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr + ); + pSegcsr->bLookup = 1; + } + } + + for(i=1; bFound==0 && i<p->nIndex; i++){ + if( p->aIndex[i].nPrefix==nTerm+1 ){ + bFound = 1; + rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, + i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr + ); + if( rc==SQLITE_OK ){ + rc = fts3SegReaderCursorAddZero( + p, pCsr->iLangid, zTerm, nTerm, pSegcsr + ); + } + } + } + } + + if( bFound==0 ){ + rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid, + 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr + ); + pSegcsr->bLookup = !isPrefix; + } + } + + *ppSegcsr = pSegcsr; + return rc; +} + +/* +** Free an Fts3MultiSegReader allocated by fts3TermSegReaderCursor(). +*/ +static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){ + sqlite3Fts3SegReaderFinish(pSegcsr); + sqlite3_free(pSegcsr); +} + +/* +** This function retrieves the doclist for the specified term (or term +** prefix) from the database. +*/ +static int fts3TermSelect( + Fts3Table *p, /* Virtual table handle */ + Fts3PhraseToken *pTok, /* Token to query for */ + int iColumn, /* Column to query (or -ve for all columns) */ + int *pnOut, /* OUT: Size of buffer at *ppOut */ + char **ppOut /* OUT: Malloced result buffer */ +){ + int rc; /* Return code */ + Fts3MultiSegReader *pSegcsr; /* Seg-reader cursor for this term */ + TermSelect tsc; /* Object for pair-wise doclist merging */ + Fts3SegFilter filter; /* Segment term filter configuration */ + + pSegcsr = pTok->pSegcsr; + memset(&tsc, 0, sizeof(TermSelect)); + + filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS + | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0) + | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0) + | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0); + filter.iCol = iColumn; + filter.zTerm = pTok->z; + filter.nTerm = pTok->n; + + rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter); + while( SQLITE_OK==rc + && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr)) + ){ + rc = fts3TermSelectMerge(p, &tsc, pSegcsr->aDoclist, pSegcsr->nDoclist); + } + + if( rc==SQLITE_OK ){ + rc = fts3TermSelectFinishMerge(p, &tsc); + } + if( rc==SQLITE_OK ){ + *ppOut = tsc.aaOutput[0]; + *pnOut = tsc.anOutput[0]; + }else{ + int i; + for(i=0; i<SizeofArray(tsc.aaOutput); i++){ + sqlite3_free(tsc.aaOutput[i]); + } + } + + fts3SegReaderCursorFree(pSegcsr); + pTok->pSegcsr = 0; + return rc; +} + +/* +** This function counts the total number of docids in the doclist stored +** in buffer aList[], size nList bytes. +** +** If the isPoslist argument is true, then it is assumed that the doclist +** contains a position-list following each docid. Otherwise, it is assumed +** that the doclist is simply a list of docids stored as delta encoded +** varints. +*/ +static int fts3DoclistCountDocids(char *aList, int nList){ + int nDoc = 0; /* Return value */ + if( aList ){ + char *aEnd = &aList[nList]; /* Pointer to one byte after EOF */ + char *p = aList; /* Cursor */ + while( p<aEnd ){ + nDoc++; + while( (*p++)&0x80 ); /* Skip docid varint */ + fts3PoslistCopy(0, &p); /* Skip over position list */ + } + } + + return nDoc; +} + +/* +** Advance the cursor to the next row in the %_content table that +** matches the search criteria. For a MATCH search, this will be +** the next row that matches. For a full-table scan, this will be +** simply the next row in the %_content table. For a docid lookup, +** this routine simply sets the EOF flag. +** +** Return SQLITE_OK if nothing goes wrong. SQLITE_OK is returned +** even if we reach end-of-file. The fts3EofMethod() will be called +** subsequently to determine whether or not an EOF was hit. +*/ +static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){ + int rc; + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor; + if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){ + Fts3Table *pTab = (Fts3Table*)pCursor->pVtab; + pTab->bLock++; + if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){ + pCsr->isEof = 1; + rc = sqlite3_reset(pCsr->pStmt); + }else{ + pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0); + rc = SQLITE_OK; + } + pTab->bLock--; + }else{ + rc = fts3EvalNext((Fts3Cursor *)pCursor); + } + assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 ); + return rc; +} + +/* +** If the numeric type of argument pVal is "integer", then return it +** converted to a 64-bit signed integer. Otherwise, return a copy of +** the second parameter, iDefault. +*/ +static sqlite3_int64 fts3DocidRange(sqlite3_value *pVal, i64 iDefault){ + if( pVal ){ + int eType = sqlite3_value_numeric_type(pVal); + if( eType==SQLITE_INTEGER ){ + return sqlite3_value_int64(pVal); + } + } + return iDefault; +} + +/* +** This is the xFilter interface for the virtual table. See +** the virtual table xFilter method documentation for additional +** information. +** +** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against +** the %_content table. +** +** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry +** in the %_content table. +** +** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index. The +** column on the left-hand side of the MATCH operator is column +** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed. argv[0] is the right-hand +** side of the MATCH operator. +*/ +static int fts3FilterMethod( + sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */ + int idxNum, /* Strategy index */ + const char *idxStr, /* Unused */ + int nVal, /* Number of elements in apVal */ + sqlite3_value **apVal /* Arguments for the indexing scheme */ +){ + int rc = SQLITE_OK; + char *zSql; /* SQL statement used to access %_content */ + int eSearch; + Fts3Table *p = (Fts3Table *)pCursor->pVtab; + Fts3Cursor *pCsr = (Fts3Cursor *)pCursor; + + sqlite3_value *pCons = 0; /* The MATCH or rowid constraint, if any */ + sqlite3_value *pLangid = 0; /* The "langid = ?" constraint, if any */ + sqlite3_value *pDocidGe = 0; /* The "docid >= ?" constraint, if any */ + sqlite3_value *pDocidLe = 0; /* The "docid <= ?" constraint, if any */ + int iIdx; + + UNUSED_PARAMETER(idxStr); + UNUSED_PARAMETER(nVal); + + if( p->bLock ){ + return SQLITE_ERROR; + } + + eSearch = (idxNum & 0x0000FFFF); + assert( eSearch>=0 && eSearch<=(FTS3_FULLTEXT_SEARCH+p->nColumn) ); + assert( p->pSegments==0 ); + + /* Collect arguments into local variables */ + iIdx = 0; + if( eSearch!=FTS3_FULLSCAN_SEARCH ) pCons = apVal[iIdx++]; + if( idxNum & FTS3_HAVE_LANGID ) pLangid = apVal[iIdx++]; + if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++]; + if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++]; + assert( iIdx==nVal ); + + /* In case the cursor has been used before, clear it now. */ + fts3ClearCursor(pCsr); + + /* Set the lower and upper bounds on docids to return */ + pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64); + pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64); + + if( idxStr ){ + pCsr->bDesc = (idxStr[0]=='D'); + }else{ + pCsr->bDesc = p->bDescIdx; + } + pCsr->eSearch = (i16)eSearch; + + if( eSearch!=FTS3_DOCID_SEARCH && eSearch!=FTS3_FULLSCAN_SEARCH ){ + int iCol = eSearch-FTS3_FULLTEXT_SEARCH; + const char *zQuery = (const char *)sqlite3_value_text(pCons); + + if( zQuery==0 && sqlite3_value_type(pCons)!=SQLITE_NULL ){ + return SQLITE_NOMEM; + } + + pCsr->iLangid = 0; + if( pLangid ) pCsr->iLangid = sqlite3_value_int(pLangid); + + assert( p->base.zErrMsg==0 ); + rc = sqlite3Fts3ExprParse(p->pTokenizer, pCsr->iLangid, + p->azColumn, p->bFts4, p->nColumn, iCol, zQuery, -1, &pCsr->pExpr, + &p->base.zErrMsg + ); + if( rc!=SQLITE_OK ){ + return rc; + } + + rc = fts3EvalStart(pCsr); + sqlite3Fts3SegmentsClose(p); + if( rc!=SQLITE_OK ) return rc; + pCsr->pNextId = pCsr->aDoclist; + pCsr->iPrevId = 0; + } + + /* Compile a SELECT statement for this cursor. For a full-table-scan, the + ** statement loops through all rows of the %_content table. For a + ** full-text query or docid lookup, the statement retrieves a single + ** row by docid. + */ + if( eSearch==FTS3_FULLSCAN_SEARCH ){ + if( pDocidGe || pDocidLe ){ + zSql = sqlite3_mprintf( + "SELECT %s WHERE rowid BETWEEN %lld AND %lld ORDER BY rowid %s", + p->zReadExprlist, pCsr->iMinDocid, pCsr->iMaxDocid, + (pCsr->bDesc ? "DESC" : "ASC") + ); + }else{ + zSql = sqlite3_mprintf("SELECT %s ORDER BY rowid %s", + p->zReadExprlist, (pCsr->bDesc ? "DESC" : "ASC") + ); + } + if( zSql ){ + p->bLock++; + rc = sqlite3_prepare_v3( + p->db,zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0 + ); + p->bLock--; + sqlite3_free(zSql); + }else{ + rc = SQLITE_NOMEM; + } + }else if( eSearch==FTS3_DOCID_SEARCH ){ + rc = fts3CursorSeekStmt(pCsr); + if( rc==SQLITE_OK ){ + rc = sqlite3_bind_value(pCsr->pStmt, 1, pCons); + } + } + if( rc!=SQLITE_OK ) return rc; + + return fts3NextMethod(pCursor); +} + +/* +** This is the xEof method of the virtual table. SQLite calls this +** routine to find out if it has reached the end of a result set. +*/ +static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){ + Fts3Cursor *pCsr = (Fts3Cursor*)pCursor; + if( pCsr->isEof ){ + fts3ClearCursor(pCsr); + pCsr->isEof = 1; + } + return pCsr->isEof; +} + +/* +** This is the xRowid method. The SQLite core calls this routine to +** retrieve the rowid for the current row of the result set. fts3 +** exposes %_content.docid as the rowid for the virtual table. The +** rowid should be written to *pRowid. +*/ +static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){ + Fts3Cursor *pCsr = (Fts3Cursor *) pCursor; + *pRowid = pCsr->iPrevId; + return SQLITE_OK; +} + +/* +** This is the xColumn method, called by SQLite to request a value from +** the row that the supplied cursor currently points to. +** +** If: +** +** (iCol < p->nColumn) -> The value of the iCol'th user column. +** (iCol == p->nColumn) -> Magic column with the same name as the table. +** (iCol == p->nColumn+1) -> Docid column +** (iCol == p->nColumn+2) -> Langid column +*/ +static int fts3ColumnMethod( + sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */ + sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */ + int iCol /* Index of column to read value from */ +){ + int rc = SQLITE_OK; /* Return Code */ + Fts3Cursor *pCsr = (Fts3Cursor *) pCursor; + Fts3Table *p = (Fts3Table *)pCursor->pVtab; + + /* The column value supplied by SQLite must be in range. */ + assert( iCol>=0 && iCol<=p->nColumn+2 ); + + switch( iCol-p->nColumn ){ + case 0: + /* The special 'table-name' column */ + sqlite3_result_pointer(pCtx, pCsr, "fts3cursor", 0); + break; + + case 1: + /* The docid column */ + sqlite3_result_int64(pCtx, pCsr->iPrevId); + break; + + case 2: + if( pCsr->pExpr ){ + sqlite3_result_int64(pCtx, pCsr->iLangid); + break; + }else if( p->zLanguageid==0 ){ + sqlite3_result_int(pCtx, 0); + break; + }else{ + iCol = p->nColumn; + /* no break */ deliberate_fall_through + } + + default: + /* A user column. Or, if this is a full-table scan, possibly the + ** language-id column. Seek the cursor. */ + rc = fts3CursorSeek(0, pCsr); + if( rc==SQLITE_OK && sqlite3_data_count(pCsr->pStmt)-1>iCol ){ + sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1)); + } + break; + } + + assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 ); + return rc; +} + +/* +** This function is the implementation of the xUpdate callback used by +** FTS3 virtual tables. It is invoked by SQLite each time a row is to be +** inserted, updated or deleted. +*/ +static int fts3UpdateMethod( + sqlite3_vtab *pVtab, /* Virtual table handle */ + int nArg, /* Size of argument array */ + sqlite3_value **apVal, /* Array of arguments */ + sqlite_int64 *pRowid /* OUT: The affected (or effected) rowid */ +){ + return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid); +} + +/* +** Implementation of xSync() method. Flush the contents of the pending-terms +** hash-table to the database. +*/ +static int fts3SyncMethod(sqlite3_vtab *pVtab){ + + /* Following an incremental-merge operation, assuming that the input + ** segments are not completely consumed (the usual case), they are updated + ** in place to remove the entries that have already been merged. This + ** involves updating the leaf block that contains the smallest unmerged + ** entry and each block (if any) between the leaf and the root node. So + ** if the height of the input segment b-trees is N, and input segments + ** are merged eight at a time, updating the input segments at the end + ** of an incremental-merge requires writing (8*(1+N)) blocks. N is usually + ** small - often between 0 and 2. So the overhead of the incremental + ** merge is somewhere between 8 and 24 blocks. To avoid this overhead + ** dwarfing the actual productive work accomplished, the incremental merge + ** is only attempted if it will write at least 64 leaf blocks. Hence + ** nMinMerge. + ** + ** Of course, updating the input segments also involves deleting a bunch + ** of blocks from the segments table. But this is not considered overhead + ** as it would also be required by a crisis-merge that used the same input + ** segments. + */ + const u32 nMinMerge = 64; /* Minimum amount of incr-merge work to do */ + + Fts3Table *p = (Fts3Table*)pVtab; + int rc; + i64 iLastRowid = sqlite3_last_insert_rowid(p->db); + + rc = sqlite3Fts3PendingTermsFlush(p); + if( rc==SQLITE_OK + && p->nLeafAdd>(nMinMerge/16) + && p->nAutoincrmerge && p->nAutoincrmerge!=0xff + ){ + int mxLevel = 0; /* Maximum relative level value in db */ + int A; /* Incr-merge parameter A */ + + rc = sqlite3Fts3MaxLevel(p, &mxLevel); + assert( rc==SQLITE_OK || mxLevel==0 ); + A = p->nLeafAdd * mxLevel; + A += (A/2); + if( A>(int)nMinMerge ) rc = sqlite3Fts3Incrmerge(p, A, p->nAutoincrmerge); + } + sqlite3Fts3SegmentsClose(p); + sqlite3_set_last_insert_rowid(p->db, iLastRowid); + return rc; +} + +/* +** If it is currently unknown whether or not the FTS table has an %_stat +** table (if p->bHasStat==2), attempt to determine this (set p->bHasStat +** to 0 or 1). Return SQLITE_OK if successful, or an SQLite error code +** if an error occurs. +*/ +static int fts3SetHasStat(Fts3Table *p){ + int rc = SQLITE_OK; + if( p->bHasStat==2 ){ + char *zTbl = sqlite3_mprintf("%s_stat", p->zName); + if( zTbl ){ + int res = sqlite3_table_column_metadata(p->db, p->zDb, zTbl, 0,0,0,0,0,0); + sqlite3_free(zTbl); + p->bHasStat = (res==SQLITE_OK); + }else{ + rc = SQLITE_NOMEM; + } + } + return rc; +} + +/* +** Implementation of xBegin() method. +*/ +static int fts3BeginMethod(sqlite3_vtab *pVtab){ + Fts3Table *p = (Fts3Table*)pVtab; + int rc; + UNUSED_PARAMETER(pVtab); + assert( p->pSegments==0 ); + assert( p->nPendingData==0 ); + assert( p->inTransaction!=1 ); + p->nLeafAdd = 0; + rc = fts3SetHasStat(p); +#ifdef SQLITE_DEBUG + if( rc==SQLITE_OK ){ + p->inTransaction = 1; + p->mxSavepoint = -1; + } +#endif + return rc; +} + +/* +** Implementation of xCommit() method. This is a no-op. The contents of +** the pending-terms hash-table have already been flushed into the database +** by fts3SyncMethod(). +*/ +static int fts3CommitMethod(sqlite3_vtab *pVtab){ + TESTONLY( Fts3Table *p = (Fts3Table*)pVtab ); + UNUSED_PARAMETER(pVtab); + assert( p->nPendingData==0 ); + assert( p->inTransaction!=0 ); + assert( p->pSegments==0 ); + TESTONLY( p->inTransaction = 0 ); + TESTONLY( p->mxSavepoint = -1; ); + return SQLITE_OK; +} + +/* +** Implementation of xRollback(). Discard the contents of the pending-terms +** hash-table. Any changes made to the database are reverted by SQLite. +*/ +static int fts3RollbackMethod(sqlite3_vtab *pVtab){ + Fts3Table *p = (Fts3Table*)pVtab; + sqlite3Fts3PendingTermsClear(p); + assert( p->inTransaction!=0 ); + TESTONLY( p->inTransaction = 0 ); + TESTONLY( p->mxSavepoint = -1; ); + return SQLITE_OK; +} + +/* +** When called, *ppPoslist must point to the byte immediately following the +** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function +** moves *ppPoslist so that it instead points to the first byte of the +** same position list. +*/ +static void fts3ReversePoslist(char *pStart, char **ppPoslist){ + char *p = &(*ppPoslist)[-2]; + char c = 0; + + /* Skip backwards passed any trailing 0x00 bytes added by NearTrim() */ + while( p>pStart && (c=*p--)==0 ); + + /* Search backwards for a varint with value zero (the end of the previous + ** poslist). This is an 0x00 byte preceded by some byte that does not + ** have the 0x80 bit set. */ + while( p>pStart && (*p & 0x80) | c ){ + c = *p--; + } + assert( p==pStart || c==0 ); + + /* At this point p points to that preceding byte without the 0x80 bit + ** set. So to find the start of the poslist, skip forward 2 bytes then + ** over a varint. + ** + ** Normally. The other case is that p==pStart and the poslist to return + ** is the first in the doclist. In this case do not skip forward 2 bytes. + ** The second part of the if condition (c==0 && *ppPoslist>&p[2]) + ** is required for cases where the first byte of a doclist and the + ** doclist is empty. For example, if the first docid is 10, a doclist + ** that begins with: + ** + ** 0x0A 0x00 <next docid delta varint> + */ + if( p>pStart || (c==0 && *ppPoslist>&p[2]) ){ p = &p[2]; } + while( *p++&0x80 ); + *ppPoslist = p; +} + +/* +** Helper function used by the implementation of the overloaded snippet(), +** offsets() and optimize() SQL functions. +** +** If the value passed as the third argument is a blob of size +** sizeof(Fts3Cursor*), then the blob contents are copied to the +** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error +** message is written to context pContext and SQLITE_ERROR returned. The +** string passed via zFunc is used as part of the error message. +*/ +static int fts3FunctionArg( + sqlite3_context *pContext, /* SQL function call context */ + const char *zFunc, /* Function name */ + sqlite3_value *pVal, /* argv[0] passed to function */ + Fts3Cursor **ppCsr /* OUT: Store cursor handle here */ +){ + int rc; + *ppCsr = (Fts3Cursor*)sqlite3_value_pointer(pVal, "fts3cursor"); + if( (*ppCsr)!=0 ){ + rc = SQLITE_OK; + }else{ + char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc); + sqlite3_result_error(pContext, zErr, -1); + sqlite3_free(zErr); + rc = SQLITE_ERROR; + } + return rc; +} + +/* +** Implementation of the snippet() function for FTS3 +*/ +static void fts3SnippetFunc( + sqlite3_context *pContext, /* SQLite function call context */ + int nVal, /* Size of apVal[] array */ + sqlite3_value **apVal /* Array of arguments */ +){ + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */ + const char *zStart = "<b>"; + const char *zEnd = "</b>"; + const char *zEllipsis = "<b>...</b>"; + int iCol = -1; + int nToken = 15; /* Default number of tokens in snippet */ + + /* There must be at least one argument passed to this function (otherwise + ** the non-overloaded version would have been called instead of this one). + */ + assert( nVal>=1 ); + + if( nVal>6 ){ + sqlite3_result_error(pContext, + "wrong number of arguments to function snippet()", -1); + return; + } + if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return; + + switch( nVal ){ + case 6: nToken = sqlite3_value_int(apVal[5]); + /* no break */ deliberate_fall_through + case 5: iCol = sqlite3_value_int(apVal[4]); + /* no break */ deliberate_fall_through + case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]); + /* no break */ deliberate_fall_through + case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]); + /* no break */ deliberate_fall_through + case 2: zStart = (const char*)sqlite3_value_text(apVal[1]); + } + if( !zEllipsis || !zEnd || !zStart ){ + sqlite3_result_error_nomem(pContext); + }else if( nToken==0 ){ + sqlite3_result_text(pContext, "", -1, SQLITE_STATIC); + }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){ + sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken); + } +} + +/* +** Implementation of the offsets() function for FTS3 +*/ +static void fts3OffsetsFunc( + sqlite3_context *pContext, /* SQLite function call context */ + int nVal, /* Size of argument array */ + sqlite3_value **apVal /* Array of arguments */ +){ + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */ + + UNUSED_PARAMETER(nVal); + + assert( nVal==1 ); + if( fts3FunctionArg(pContext, "offsets", apVal[0], &pCsr) ) return; + assert( pCsr ); + if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){ + sqlite3Fts3Offsets(pContext, pCsr); + } +} + +/* +** Implementation of the special optimize() function for FTS3. This +** function merges all segments in the database to a single segment. +** Example usage is: +** +** SELECT optimize(t) FROM t LIMIT 1; +** +** where 't' is the name of an FTS3 table. +*/ +static void fts3OptimizeFunc( + sqlite3_context *pContext, /* SQLite function call context */ + int nVal, /* Size of argument array */ + sqlite3_value **apVal /* Array of arguments */ +){ + int rc; /* Return code */ + Fts3Table *p; /* Virtual table handle */ + Fts3Cursor *pCursor; /* Cursor handle passed through apVal[0] */ + + UNUSED_PARAMETER(nVal); + + assert( nVal==1 ); + if( fts3FunctionArg(pContext, "optimize", apVal[0], &pCursor) ) return; + p = (Fts3Table *)pCursor->base.pVtab; + assert( p ); + + rc = sqlite3Fts3Optimize(p); + + switch( rc ){ + case SQLITE_OK: + sqlite3_result_text(pContext, "Index optimized", -1, SQLITE_STATIC); + break; + case SQLITE_DONE: + sqlite3_result_text(pContext, "Index already optimal", -1, SQLITE_STATIC); + break; + default: + sqlite3_result_error_code(pContext, rc); + break; + } +} + +/* +** Implementation of the matchinfo() function for FTS3 +*/ +static void fts3MatchinfoFunc( + sqlite3_context *pContext, /* SQLite function call context */ + int nVal, /* Size of argument array */ + sqlite3_value **apVal /* Array of arguments */ +){ + Fts3Cursor *pCsr; /* Cursor handle passed through apVal[0] */ + assert( nVal==1 || nVal==2 ); + if( SQLITE_OK==fts3FunctionArg(pContext, "matchinfo", apVal[0], &pCsr) ){ + const char *zArg = 0; + if( nVal>1 ){ + zArg = (const char *)sqlite3_value_text(apVal[1]); + } + sqlite3Fts3Matchinfo(pContext, pCsr, zArg); + } +} + +/* +** This routine implements the xFindFunction method for the FTS3 +** virtual table. +*/ +static int fts3FindFunctionMethod( + sqlite3_vtab *pVtab, /* Virtual table handle */ + int nArg, /* Number of SQL function arguments */ + const char *zName, /* Name of SQL function */ + void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */ + void **ppArg /* Unused */ +){ + struct Overloaded { + const char *zName; + void (*xFunc)(sqlite3_context*,int,sqlite3_value**); + } aOverload[] = { + { "snippet", fts3SnippetFunc }, + { "offsets", fts3OffsetsFunc }, + { "optimize", fts3OptimizeFunc }, + { "matchinfo", fts3MatchinfoFunc }, + }; + int i; /* Iterator variable */ + + UNUSED_PARAMETER(pVtab); + UNUSED_PARAMETER(nArg); + UNUSED_PARAMETER(ppArg); + + for(i=0; i<SizeofArray(aOverload); i++){ + if( strcmp(zName, aOverload[i].zName)==0 ){ + *pxFunc = aOverload[i].xFunc; + return 1; + } + } + + /* No function of the specified name was found. Return 0. */ + return 0; +} + +/* +** Implementation of FTS3 xRename method. Rename an fts3 table. +*/ +static int fts3RenameMethod( + sqlite3_vtab *pVtab, /* Virtual table handle */ + const char *zName /* New name of table */ +){ + Fts3Table *p = (Fts3Table *)pVtab; + sqlite3 *db = p->db; /* Database connection */ + int rc; /* Return Code */ + + /* At this point it must be known if the %_stat table exists or not. + ** So bHasStat may not be 2. */ + rc = fts3SetHasStat(p); + + /* As it happens, the pending terms table is always empty here. This is + ** because an "ALTER TABLE RENAME TABLE" statement inside a transaction + ** always opens a savepoint transaction. And the xSavepoint() method + ** flushes the pending terms table. But leave the (no-op) call to + ** PendingTermsFlush() in in case that changes. + */ + assert( p->nPendingData==0 ); + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3PendingTermsFlush(p); + } + + if( p->zContentTbl==0 ){ + fts3DbExec(&rc, db, + "ALTER TABLE %Q.'%q_content' RENAME TO '%q_content';", + p->zDb, p->zName, zName + ); + } + + if( p->bHasDocsize ){ + fts3DbExec(&rc, db, + "ALTER TABLE %Q.'%q_docsize' RENAME TO '%q_docsize';", + p->zDb, p->zName, zName + ); + } + if( p->bHasStat ){ + fts3DbExec(&rc, db, + "ALTER TABLE %Q.'%q_stat' RENAME TO '%q_stat';", + p->zDb, p->zName, zName + ); + } + fts3DbExec(&rc, db, + "ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';", + p->zDb, p->zName, zName + ); + fts3DbExec(&rc, db, + "ALTER TABLE %Q.'%q_segdir' RENAME TO '%q_segdir';", + p->zDb, p->zName, zName + ); + return rc; +} + +/* +** The xSavepoint() method. +** +** Flush the contents of the pending-terms table to disk. +*/ +static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){ + int rc = SQLITE_OK; + UNUSED_PARAMETER(iSavepoint); + assert( ((Fts3Table *)pVtab)->inTransaction ); + assert( ((Fts3Table *)pVtab)->mxSavepoint <= iSavepoint ); + TESTONLY( ((Fts3Table *)pVtab)->mxSavepoint = iSavepoint ); + if( ((Fts3Table *)pVtab)->bIgnoreSavepoint==0 ){ + rc = fts3SyncMethod(pVtab); + } + return rc; +} + +/* +** The xRelease() method. +** +** This is a no-op. +*/ +static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){ + TESTONLY( Fts3Table *p = (Fts3Table*)pVtab ); + UNUSED_PARAMETER(iSavepoint); + UNUSED_PARAMETER(pVtab); + assert( p->inTransaction ); + assert( p->mxSavepoint >= iSavepoint ); + TESTONLY( p->mxSavepoint = iSavepoint-1 ); + return SQLITE_OK; +} + +/* +** The xRollbackTo() method. +** +** Discard the contents of the pending terms table. +*/ +static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){ + Fts3Table *p = (Fts3Table*)pVtab; + UNUSED_PARAMETER(iSavepoint); + assert( p->inTransaction ); + TESTONLY( p->mxSavepoint = iSavepoint ); + sqlite3Fts3PendingTermsClear(p); + return SQLITE_OK; +} + +/* +** Return true if zName is the extension on one of the shadow tables used +** by this module. +*/ +static int fts3ShadowName(const char *zName){ + static const char *azName[] = { + "content", "docsize", "segdir", "segments", "stat", + }; + unsigned int i; + for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){ + if( sqlite3_stricmp(zName, azName[i])==0 ) return 1; + } + return 0; +} + +static const sqlite3_module fts3Module = { + /* iVersion */ 3, + /* xCreate */ fts3CreateMethod, + /* xConnect */ fts3ConnectMethod, + /* xBestIndex */ fts3BestIndexMethod, + /* xDisconnect */ fts3DisconnectMethod, + /* xDestroy */ fts3DestroyMethod, + /* xOpen */ fts3OpenMethod, + /* xClose */ fts3CloseMethod, + /* xFilter */ fts3FilterMethod, + /* xNext */ fts3NextMethod, + /* xEof */ fts3EofMethod, + /* xColumn */ fts3ColumnMethod, + /* xRowid */ fts3RowidMethod, + /* xUpdate */ fts3UpdateMethod, + /* xBegin */ fts3BeginMethod, + /* xSync */ fts3SyncMethod, + /* xCommit */ fts3CommitMethod, + /* xRollback */ fts3RollbackMethod, + /* xFindFunction */ fts3FindFunctionMethod, + /* xRename */ fts3RenameMethod, + /* xSavepoint */ fts3SavepointMethod, + /* xRelease */ fts3ReleaseMethod, + /* xRollbackTo */ fts3RollbackToMethod, + /* xShadowName */ fts3ShadowName, +}; + +/* +** This function is registered as the module destructor (called when an +** FTS3 enabled database connection is closed). It frees the memory +** allocated for the tokenizer hash table. +*/ +static void hashDestroy(void *p){ + Fts3HashWrapper *pHash = (Fts3HashWrapper *)p; + pHash->nRef--; + if( pHash->nRef<=0 ){ + sqlite3Fts3HashClear(&pHash->hash); + sqlite3_free(pHash); + } +} + +/* +** The fts3 built-in tokenizers - "simple", "porter" and "icu"- are +** implemented in files fts3_tokenizer1.c, fts3_porter.c and fts3_icu.c +** respectively. The following three forward declarations are for functions +** declared in these files used to retrieve the respective implementations. +** +** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed +** to by the argument to point to the "simple" tokenizer implementation. +** And so on. +*/ +void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule); +void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule); +#ifndef SQLITE_DISABLE_FTS3_UNICODE +void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const**ppModule); +#endif +#ifdef SQLITE_ENABLE_ICU +void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule); +#endif + +/* +** Initialize the fts3 extension. If this extension is built as part +** of the sqlite library, then this function is called directly by +** SQLite. If fts3 is built as a dynamically loadable extension, this +** function is called by the sqlite3_extension_init() entry point. +*/ +int sqlite3Fts3Init(sqlite3 *db){ + int rc = SQLITE_OK; + Fts3HashWrapper *pHash = 0; + const sqlite3_tokenizer_module *pSimple = 0; + const sqlite3_tokenizer_module *pPorter = 0; +#ifndef SQLITE_DISABLE_FTS3_UNICODE + const sqlite3_tokenizer_module *pUnicode = 0; +#endif + +#ifdef SQLITE_ENABLE_ICU + const sqlite3_tokenizer_module *pIcu = 0; + sqlite3Fts3IcuTokenizerModule(&pIcu); +#endif + +#ifndef SQLITE_DISABLE_FTS3_UNICODE + sqlite3Fts3UnicodeTokenizer(&pUnicode); +#endif + +#ifdef SQLITE_TEST + rc = sqlite3Fts3InitTerm(db); + if( rc!=SQLITE_OK ) return rc; +#endif + + rc = sqlite3Fts3InitAux(db); + if( rc!=SQLITE_OK ) return rc; + + sqlite3Fts3SimpleTokenizerModule(&pSimple); + sqlite3Fts3PorterTokenizerModule(&pPorter); + + /* Allocate and initialize the hash-table used to store tokenizers. */ + pHash = sqlite3_malloc(sizeof(Fts3HashWrapper)); + if( !pHash ){ + rc = SQLITE_NOMEM; + }else{ + sqlite3Fts3HashInit(&pHash->hash, FTS3_HASH_STRING, 1); + pHash->nRef = 0; + } + + /* Load the built-in tokenizers into the hash table */ + if( rc==SQLITE_OK ){ + if( sqlite3Fts3HashInsert(&pHash->hash, "simple", 7, (void *)pSimple) + || sqlite3Fts3HashInsert(&pHash->hash, "porter", 7, (void *)pPorter) + +#ifndef SQLITE_DISABLE_FTS3_UNICODE + || sqlite3Fts3HashInsert(&pHash->hash, "unicode61", 10, (void *)pUnicode) +#endif +#ifdef SQLITE_ENABLE_ICU + || (pIcu && sqlite3Fts3HashInsert(&pHash->hash, "icu", 4, (void *)pIcu)) +#endif + ){ + rc = SQLITE_NOMEM; + } + } + +#ifdef SQLITE_TEST + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3ExprInitTestInterface(db, &pHash->hash); + } +#endif + + /* Create the virtual table wrapper around the hash-table and overload + ** the four scalar functions. If this is successful, register the + ** module with sqlite. + */ + if( SQLITE_OK==rc + && SQLITE_OK==(rc=sqlite3Fts3InitHashTable(db,&pHash->hash,"fts3_tokenizer")) + && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1)) + && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1)) + && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1)) + && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2)) + && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1)) + ){ + pHash->nRef++; + rc = sqlite3_create_module_v2( + db, "fts3", &fts3Module, (void *)pHash, hashDestroy + ); + if( rc==SQLITE_OK ){ + pHash->nRef++; + rc = sqlite3_create_module_v2( + db, "fts4", &fts3Module, (void *)pHash, hashDestroy + ); + } + if( rc==SQLITE_OK ){ + pHash->nRef++; + rc = sqlite3Fts3InitTok(db, (void *)pHash, hashDestroy); + } + return rc; + } + + + /* An error has occurred. Delete the hash table and return the error code. */ + assert( rc!=SQLITE_OK ); + if( pHash ){ + sqlite3Fts3HashClear(&pHash->hash); + sqlite3_free(pHash); + } + return rc; +} + +/* +** Allocate an Fts3MultiSegReader for each token in the expression headed +** by pExpr. +** +** An Fts3SegReader object is a cursor that can seek or scan a range of +** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple +** Fts3SegReader objects internally to provide an interface to seek or scan +** within the union of all segments of a b-tree. Hence the name. +** +** If the allocated Fts3MultiSegReader just seeks to a single entry in a +** segment b-tree (if the term is not a prefix or it is a prefix for which +** there exists prefix b-tree of the right length) then it may be traversed +** and merged incrementally. Otherwise, it has to be merged into an in-memory +** doclist and then traversed. +*/ +static void fts3EvalAllocateReaders( + Fts3Cursor *pCsr, /* FTS cursor handle */ + Fts3Expr *pExpr, /* Allocate readers for this expression */ + int *pnToken, /* OUT: Total number of tokens in phrase. */ + int *pnOr, /* OUT: Total number of OR nodes in expr. */ + int *pRc /* IN/OUT: Error code */ +){ + if( pExpr && SQLITE_OK==*pRc ){ + if( pExpr->eType==FTSQUERY_PHRASE ){ + int i; + int nToken = pExpr->pPhrase->nToken; + *pnToken += nToken; + for(i=0; i<nToken; i++){ + Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i]; + int rc = fts3TermSegReaderCursor(pCsr, + pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr + ); + if( rc!=SQLITE_OK ){ + *pRc = rc; + return; + } + } + assert( pExpr->pPhrase->iDoclistToken==0 ); + pExpr->pPhrase->iDoclistToken = -1; + }else{ + *pnOr += (pExpr->eType==FTSQUERY_OR); + fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc); + fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc); + } + } +} + +/* +** Arguments pList/nList contain the doclist for token iToken of phrase p. +** It is merged into the main doclist stored in p->doclist.aAll/nAll. +** +** This function assumes that pList points to a buffer allocated using +** sqlite3_malloc(). This function takes responsibility for eventually +** freeing the buffer. +** +** SQLITE_OK is returned if successful, or SQLITE_NOMEM if an error occurs. +*/ +static int fts3EvalPhraseMergeToken( + Fts3Table *pTab, /* FTS Table pointer */ + Fts3Phrase *p, /* Phrase to merge pList/nList into */ + int iToken, /* Token pList/nList corresponds to */ + char *pList, /* Pointer to doclist */ + int nList /* Number of bytes in pList */ +){ + int rc = SQLITE_OK; + assert( iToken!=p->iDoclistToken ); + + if( pList==0 ){ + sqlite3_free(p->doclist.aAll); + p->doclist.aAll = 0; + p->doclist.nAll = 0; + } + + else if( p->iDoclistToken<0 ){ + p->doclist.aAll = pList; + p->doclist.nAll = nList; + } + + else if( p->doclist.aAll==0 ){ + sqlite3_free(pList); + } + + else { + char *pLeft; + char *pRight; + int nLeft; + int nRight; + int nDiff; + + if( p->iDoclistToken<iToken ){ + pLeft = p->doclist.aAll; + nLeft = p->doclist.nAll; + pRight = pList; + nRight = nList; + nDiff = iToken - p->iDoclistToken; + }else{ + pRight = p->doclist.aAll; + nRight = p->doclist.nAll; + pLeft = pList; + nLeft = nList; + nDiff = p->iDoclistToken - iToken; + } + + rc = fts3DoclistPhraseMerge( + pTab->bDescIdx, nDiff, pLeft, nLeft, &pRight, &nRight + ); + sqlite3_free(pLeft); + p->doclist.aAll = pRight; + p->doclist.nAll = nRight; + } + + if( iToken>p->iDoclistToken ) p->iDoclistToken = iToken; + return rc; +} + +/* +** Load the doclist for phrase p into p->doclist.aAll/nAll. The loaded doclist +** does not take deferred tokens into account. +** +** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code. +*/ +static int fts3EvalPhraseLoad( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Phrase *p /* Phrase object */ +){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + int iToken; + int rc = SQLITE_OK; + + for(iToken=0; rc==SQLITE_OK && iToken<p->nToken; iToken++){ + Fts3PhraseToken *pToken = &p->aToken[iToken]; + assert( pToken->pDeferred==0 || pToken->pSegcsr==0 ); + + if( pToken->pSegcsr ){ + int nThis = 0; + char *pThis = 0; + rc = fts3TermSelect(pTab, pToken, p->iColumn, &nThis, &pThis); + if( rc==SQLITE_OK ){ + rc = fts3EvalPhraseMergeToken(pTab, p, iToken, pThis, nThis); + } + } + assert( pToken->pSegcsr==0 ); + } + + return rc; +} + +#ifndef SQLITE_DISABLE_FTS4_DEFERRED +/* +** This function is called on each phrase after the position lists for +** any deferred tokens have been loaded into memory. It updates the phrases +** current position list to include only those positions that are really +** instances of the phrase (after considering deferred tokens). If this +** means that the phrase does not appear in the current row, doclist.pList +** and doclist.nList are both zeroed. +** +** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code. +*/ +static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){ + int iToken; /* Used to iterate through phrase tokens */ + char *aPoslist = 0; /* Position list for deferred tokens */ + int nPoslist = 0; /* Number of bytes in aPoslist */ + int iPrev = -1; /* Token number of previous deferred token */ + char *aFree = (pPhrase->doclist.bFreeList ? pPhrase->doclist.pList : 0); + + for(iToken=0; iToken<pPhrase->nToken; iToken++){ + Fts3PhraseToken *pToken = &pPhrase->aToken[iToken]; + Fts3DeferredToken *pDeferred = pToken->pDeferred; + + if( pDeferred ){ + char *pList; + int nList; + int rc = sqlite3Fts3DeferredTokenList(pDeferred, &pList, &nList); + if( rc!=SQLITE_OK ) return rc; + + if( pList==0 ){ + sqlite3_free(aPoslist); + sqlite3_free(aFree); + pPhrase->doclist.pList = 0; + pPhrase->doclist.nList = 0; + return SQLITE_OK; + + }else if( aPoslist==0 ){ + aPoslist = pList; + nPoslist = nList; + + }else{ + char *aOut = pList; + char *p1 = aPoslist; + char *p2 = aOut; + + assert( iPrev>=0 ); + fts3PoslistPhraseMerge(&aOut, iToken-iPrev, 0, 1, &p1, &p2); + sqlite3_free(aPoslist); + aPoslist = pList; + nPoslist = (int)(aOut - aPoslist); + if( nPoslist==0 ){ + sqlite3_free(aPoslist); + sqlite3_free(aFree); + pPhrase->doclist.pList = 0; + pPhrase->doclist.nList = 0; + return SQLITE_OK; + } + } + iPrev = iToken; + } + } + + if( iPrev>=0 ){ + int nMaxUndeferred = pPhrase->iDoclistToken; + if( nMaxUndeferred<0 ){ + pPhrase->doclist.pList = aPoslist; + pPhrase->doclist.nList = nPoslist; + pPhrase->doclist.iDocid = pCsr->iPrevId; + pPhrase->doclist.bFreeList = 1; + }else{ + int nDistance; + char *p1; + char *p2; + char *aOut; + + if( nMaxUndeferred>iPrev ){ + p1 = aPoslist; + p2 = pPhrase->doclist.pList; + nDistance = nMaxUndeferred - iPrev; + }else{ + p1 = pPhrase->doclist.pList; + p2 = aPoslist; + nDistance = iPrev - nMaxUndeferred; + } + + aOut = (char *)sqlite3Fts3MallocZero(nPoslist+FTS3_BUFFER_PADDING); + if( !aOut ){ + sqlite3_free(aPoslist); + return SQLITE_NOMEM; + } + + pPhrase->doclist.pList = aOut; + assert( p1 && p2 ); + if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){ + pPhrase->doclist.bFreeList = 1; + pPhrase->doclist.nList = (int)(aOut - pPhrase->doclist.pList); + }else{ + sqlite3_free(aOut); + pPhrase->doclist.pList = 0; + pPhrase->doclist.nList = 0; + } + sqlite3_free(aPoslist); + } + } + + if( pPhrase->doclist.pList!=aFree ) sqlite3_free(aFree); + return SQLITE_OK; +} +#endif /* SQLITE_DISABLE_FTS4_DEFERRED */ + +/* +** Maximum number of tokens a phrase may have to be considered for the +** incremental doclists strategy. +*/ +#define MAX_INCR_PHRASE_TOKENS 4 + +/* +** This function is called for each Fts3Phrase in a full-text query +** expression to initialize the mechanism for returning rows. Once this +** function has been called successfully on an Fts3Phrase, it may be +** used with fts3EvalPhraseNext() to iterate through the matching docids. +** +** If parameter bOptOk is true, then the phrase may (or may not) use the +** incremental loading strategy. Otherwise, the entire doclist is loaded into +** memory within this call. +** +** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code. +*/ +static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + int rc = SQLITE_OK; /* Error code */ + int i; + + /* Determine if doclists may be loaded from disk incrementally. This is + ** possible if the bOptOk argument is true, the FTS doclists will be + ** scanned in forward order, and the phrase consists of + ** MAX_INCR_PHRASE_TOKENS or fewer tokens, none of which are are "^first" + ** tokens or prefix tokens that cannot use a prefix-index. */ + int bHaveIncr = 0; + int bIncrOk = (bOptOk + && pCsr->bDesc==pTab->bDescIdx + && p->nToken<=MAX_INCR_PHRASE_TOKENS && p->nToken>0 +#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST) + && pTab->bNoIncrDoclist==0 +#endif + ); + for(i=0; bIncrOk==1 && i<p->nToken; i++){ + Fts3PhraseToken *pToken = &p->aToken[i]; + if( pToken->bFirst || (pToken->pSegcsr!=0 && !pToken->pSegcsr->bLookup) ){ + bIncrOk = 0; + } + if( pToken->pSegcsr ) bHaveIncr = 1; + } + + if( bIncrOk && bHaveIncr ){ + /* Use the incremental approach. */ + int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn); + for(i=0; rc==SQLITE_OK && i<p->nToken; i++){ + Fts3PhraseToken *pToken = &p->aToken[i]; + Fts3MultiSegReader *pSegcsr = pToken->pSegcsr; + if( pSegcsr ){ + rc = sqlite3Fts3MsrIncrStart(pTab, pSegcsr, iCol, pToken->z, pToken->n); + } + } + p->bIncr = 1; + }else{ + /* Load the full doclist for the phrase into memory. */ + rc = fts3EvalPhraseLoad(pCsr, p); + p->bIncr = 0; + } + + assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr ); + return rc; +} + +/* +** This function is used to iterate backwards (from the end to start) +** through doclists. It is used by this module to iterate through phrase +** doclists in reverse and by the fts3_write.c module to iterate through +** pending-terms lists when writing to databases with "order=desc". +** +** The doclist may be sorted in ascending (parameter bDescIdx==0) or +** descending (parameter bDescIdx==1) order of docid. Regardless, this +** function iterates from the end of the doclist to the beginning. +*/ +void sqlite3Fts3DoclistPrev( + int bDescIdx, /* True if the doclist is desc */ + char *aDoclist, /* Pointer to entire doclist */ + int nDoclist, /* Length of aDoclist in bytes */ + char **ppIter, /* IN/OUT: Iterator pointer */ + sqlite3_int64 *piDocid, /* IN/OUT: Docid pointer */ + int *pnList, /* OUT: List length pointer */ + u8 *pbEof /* OUT: End-of-file flag */ +){ + char *p = *ppIter; + + assert( nDoclist>0 ); + assert( *pbEof==0 ); + assert_fts3_nc( p || *piDocid==0 ); + assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) ); + + if( p==0 ){ + sqlite3_int64 iDocid = 0; + char *pNext = 0; + char *pDocid = aDoclist; + char *pEnd = &aDoclist[nDoclist]; + int iMul = 1; + + while( pDocid<pEnd ){ + sqlite3_int64 iDelta; + pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta); + iDocid += (iMul * iDelta); + pNext = pDocid; + fts3PoslistCopy(0, &pDocid); + while( pDocid<pEnd && *pDocid==0 ) pDocid++; + iMul = (bDescIdx ? -1 : 1); + } + + *pnList = (int)(pEnd - pNext); + *ppIter = pNext; + *piDocid = iDocid; + }else{ + int iMul = (bDescIdx ? -1 : 1); + sqlite3_int64 iDelta; + fts3GetReverseVarint(&p, aDoclist, &iDelta); + *piDocid -= (iMul * iDelta); + + if( p==aDoclist ){ + *pbEof = 1; + }else{ + char *pSave = p; + fts3ReversePoslist(aDoclist, &p); + *pnList = (int)(pSave - p); + } + *ppIter = p; + } +} + +/* +** Iterate forwards through a doclist. +*/ +void sqlite3Fts3DoclistNext( + int bDescIdx, /* True if the doclist is desc */ + char *aDoclist, /* Pointer to entire doclist */ + int nDoclist, /* Length of aDoclist in bytes */ + char **ppIter, /* IN/OUT: Iterator pointer */ + sqlite3_int64 *piDocid, /* IN/OUT: Docid pointer */ + u8 *pbEof /* OUT: End-of-file flag */ +){ + char *p = *ppIter; + + assert( nDoclist>0 ); + assert( *pbEof==0 ); + assert_fts3_nc( p || *piDocid==0 ); + assert( !p || (p>=aDoclist && p<=&aDoclist[nDoclist]) ); + + if( p==0 ){ + p = aDoclist; + p += sqlite3Fts3GetVarint(p, piDocid); + }else{ + fts3PoslistCopy(0, &p); + while( p<&aDoclist[nDoclist] && *p==0 ) p++; + if( p>=&aDoclist[nDoclist] ){ + *pbEof = 1; + }else{ + sqlite3_int64 iVar; + p += sqlite3Fts3GetVarint(p, &iVar); + *piDocid += ((bDescIdx ? -1 : 1) * iVar); + } + } + + *ppIter = p; +} + +/* +** Advance the iterator pDL to the next entry in pDL->aAll/nAll. Set *pbEof +** to true if EOF is reached. +*/ +static void fts3EvalDlPhraseNext( + Fts3Table *pTab, + Fts3Doclist *pDL, + u8 *pbEof +){ + char *pIter; /* Used to iterate through aAll */ + char *pEnd; /* 1 byte past end of aAll */ + + if( pDL->pNextDocid ){ + pIter = pDL->pNextDocid; + assert( pDL->aAll!=0 || pIter==0 ); + }else{ + pIter = pDL->aAll; + } + + if( pIter==0 || pIter>=(pEnd = pDL->aAll + pDL->nAll) ){ + /* We have already reached the end of this doclist. EOF. */ + *pbEof = 1; + }else{ + sqlite3_int64 iDelta; + pIter += sqlite3Fts3GetVarint(pIter, &iDelta); + if( pTab->bDescIdx==0 || pDL->pNextDocid==0 ){ + pDL->iDocid += iDelta; + }else{ + pDL->iDocid -= iDelta; + } + pDL->pList = pIter; + fts3PoslistCopy(0, &pIter); + pDL->nList = (int)(pIter - pDL->pList); + + /* pIter now points just past the 0x00 that terminates the position- + ** list for document pDL->iDocid. However, if this position-list was + ** edited in place by fts3EvalNearTrim(), then pIter may not actually + ** point to the start of the next docid value. The following line deals + ** with this case by advancing pIter past the zero-padding added by + ** fts3EvalNearTrim(). */ + while( pIter<pEnd && *pIter==0 ) pIter++; + + pDL->pNextDocid = pIter; + assert( pIter>=&pDL->aAll[pDL->nAll] || *pIter ); + *pbEof = 0; + } +} + +/* +** Helper type used by fts3EvalIncrPhraseNext() and incrPhraseTokenNext(). +*/ +typedef struct TokenDoclist TokenDoclist; +struct TokenDoclist { + int bIgnore; + sqlite3_int64 iDocid; + char *pList; + int nList; +}; + +/* +** Token pToken is an incrementally loaded token that is part of a +** multi-token phrase. Advance it to the next matching document in the +** database and populate output variable *p with the details of the new +** entry. Or, if the iterator has reached EOF, set *pbEof to true. +** +** If an error occurs, return an SQLite error code. Otherwise, return +** SQLITE_OK. +*/ +static int incrPhraseTokenNext( + Fts3Table *pTab, /* Virtual table handle */ + Fts3Phrase *pPhrase, /* Phrase to advance token of */ + int iToken, /* Specific token to advance */ + TokenDoclist *p, /* OUT: Docid and doclist for new entry */ + u8 *pbEof /* OUT: True if iterator is at EOF */ +){ + int rc = SQLITE_OK; + + if( pPhrase->iDoclistToken==iToken ){ + assert( p->bIgnore==0 ); + assert( pPhrase->aToken[iToken].pSegcsr==0 ); + fts3EvalDlPhraseNext(pTab, &pPhrase->doclist, pbEof); + p->pList = pPhrase->doclist.pList; + p->nList = pPhrase->doclist.nList; + p->iDocid = pPhrase->doclist.iDocid; + }else{ + Fts3PhraseToken *pToken = &pPhrase->aToken[iToken]; + assert( pToken->pDeferred==0 ); + assert( pToken->pSegcsr || pPhrase->iDoclistToken>=0 ); + if( pToken->pSegcsr ){ + assert( p->bIgnore==0 ); + rc = sqlite3Fts3MsrIncrNext( + pTab, pToken->pSegcsr, &p->iDocid, &p->pList, &p->nList + ); + if( p->pList==0 ) *pbEof = 1; + }else{ + p->bIgnore = 1; + } + } + + return rc; +} + + +/* +** The phrase iterator passed as the second argument: +** +** * features at least one token that uses an incremental doclist, and +** +** * does not contain any deferred tokens. +** +** Advance it to the next matching documnent in the database and populate +** the Fts3Doclist.pList and nList fields. +** +** If there is no "next" entry and no error occurs, then *pbEof is set to +** 1 before returning. Otherwise, if no error occurs and the iterator is +** successfully advanced, *pbEof is set to 0. +** +** If an error occurs, return an SQLite error code. Otherwise, return +** SQLITE_OK. +*/ +static int fts3EvalIncrPhraseNext( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Phrase *p, /* Phrase object to advance to next docid */ + u8 *pbEof /* OUT: Set to 1 if EOF */ +){ + int rc = SQLITE_OK; + Fts3Doclist *pDL = &p->doclist; + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + u8 bEof = 0; + + /* This is only called if it is guaranteed that the phrase has at least + ** one incremental token. In which case the bIncr flag is set. */ + assert( p->bIncr==1 ); + + if( p->nToken==1 ){ + rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr, + &pDL->iDocid, &pDL->pList, &pDL->nList + ); + if( pDL->pList==0 ) bEof = 1; + }else{ + int bDescDoclist = pCsr->bDesc; + struct TokenDoclist a[MAX_INCR_PHRASE_TOKENS]; + + memset(a, 0, sizeof(a)); + assert( p->nToken<=MAX_INCR_PHRASE_TOKENS ); + assert( p->iDoclistToken<MAX_INCR_PHRASE_TOKENS ); + + while( bEof==0 ){ + int bMaxSet = 0; + sqlite3_int64 iMax = 0; /* Largest docid for all iterators */ + int i; /* Used to iterate through tokens */ + + /* Advance the iterator for each token in the phrase once. */ + for(i=0; rc==SQLITE_OK && i<p->nToken && bEof==0; i++){ + rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof); + if( a[i].bIgnore==0 && (bMaxSet==0 || DOCID_CMP(iMax, a[i].iDocid)<0) ){ + iMax = a[i].iDocid; + bMaxSet = 1; + } + } + assert( rc!=SQLITE_OK || (p->nToken>=1 && a[p->nToken-1].bIgnore==0) ); + assert( rc!=SQLITE_OK || bMaxSet ); + + /* Keep advancing iterators until they all point to the same document */ + for(i=0; i<p->nToken; i++){ + while( rc==SQLITE_OK && bEof==0 + && a[i].bIgnore==0 && DOCID_CMP(a[i].iDocid, iMax)<0 + ){ + rc = incrPhraseTokenNext(pTab, p, i, &a[i], &bEof); + if( DOCID_CMP(a[i].iDocid, iMax)>0 ){ + iMax = a[i].iDocid; + i = 0; + } + } + } + + /* Check if the current entries really are a phrase match */ + if( bEof==0 ){ + int nList = 0; + int nByte = a[p->nToken-1].nList; + char *aDoclist = sqlite3_malloc64((i64)nByte+FTS3_BUFFER_PADDING); + if( !aDoclist ) return SQLITE_NOMEM; + memcpy(aDoclist, a[p->nToken-1].pList, nByte+1); + memset(&aDoclist[nByte], 0, FTS3_BUFFER_PADDING); + + for(i=0; i<(p->nToken-1); i++){ + if( a[i].bIgnore==0 ){ + char *pL = a[i].pList; + char *pR = aDoclist; + char *pOut = aDoclist; + int nDist = p->nToken-1-i; + int res = fts3PoslistPhraseMerge(&pOut, nDist, 0, 1, &pL, &pR); + if( res==0 ) break; + nList = (int)(pOut - aDoclist); + } + } + if( i==(p->nToken-1) ){ + pDL->iDocid = iMax; + pDL->pList = aDoclist; + pDL->nList = nList; + pDL->bFreeList = 1; + break; + } + sqlite3_free(aDoclist); + } + } + } + + *pbEof = bEof; + return rc; +} + +/* +** Attempt to move the phrase iterator to point to the next matching docid. +** If an error occurs, return an SQLite error code. Otherwise, return +** SQLITE_OK. +** +** If there is no "next" entry and no error occurs, then *pbEof is set to +** 1 before returning. Otherwise, if no error occurs and the iterator is +** successfully advanced, *pbEof is set to 0. +*/ +static int fts3EvalPhraseNext( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Phrase *p, /* Phrase object to advance to next docid */ + u8 *pbEof /* OUT: Set to 1 if EOF */ +){ + int rc = SQLITE_OK; + Fts3Doclist *pDL = &p->doclist; + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + + if( p->bIncr ){ + rc = fts3EvalIncrPhraseNext(pCsr, p, pbEof); + }else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){ + sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll, + &pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof + ); + pDL->pList = pDL->pNextDocid; + }else{ + fts3EvalDlPhraseNext(pTab, pDL, pbEof); + } + + return rc; +} + +/* +** +** If *pRc is not SQLITE_OK when this function is called, it is a no-op. +** Otherwise, fts3EvalPhraseStart() is called on all phrases within the +** expression. Also the Fts3Expr.bDeferred variable is set to true for any +** expressions for which all descendent tokens are deferred. +** +** If parameter bOptOk is zero, then it is guaranteed that the +** Fts3Phrase.doclist.aAll/nAll variables contain the entire doclist for +** each phrase in the expression (subject to deferred token processing). +** Or, if bOptOk is non-zero, then one or more tokens within the expression +** may be loaded incrementally, meaning doclist.aAll/nAll is not available. +** +** If an error occurs within this function, *pRc is set to an SQLite error +** code before returning. +*/ +static void fts3EvalStartReaders( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Expr *pExpr, /* Expression to initialize phrases in */ + int *pRc /* IN/OUT: Error code */ +){ + if( pExpr && SQLITE_OK==*pRc ){ + if( pExpr->eType==FTSQUERY_PHRASE ){ + int nToken = pExpr->pPhrase->nToken; + if( nToken ){ + int i; + for(i=0; i<nToken; i++){ + if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break; + } + pExpr->bDeferred = (i==nToken); + } + *pRc = fts3EvalPhraseStart(pCsr, 1, pExpr->pPhrase); + }else{ + fts3EvalStartReaders(pCsr, pExpr->pLeft, pRc); + fts3EvalStartReaders(pCsr, pExpr->pRight, pRc); + pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred); + } + } +} + +/* +** An array of the following structures is assembled as part of the process +** of selecting tokens to defer before the query starts executing (as part +** of the xFilter() method). There is one element in the array for each +** token in the FTS expression. +** +** Tokens are divided into AND/NEAR clusters. All tokens in a cluster belong +** to phrases that are connected only by AND and NEAR operators (not OR or +** NOT). When determining tokens to defer, each AND/NEAR cluster is considered +** separately. The root of a tokens AND/NEAR cluster is stored in +** Fts3TokenAndCost.pRoot. +*/ +typedef struct Fts3TokenAndCost Fts3TokenAndCost; +struct Fts3TokenAndCost { + Fts3Phrase *pPhrase; /* The phrase the token belongs to */ + int iToken; /* Position of token in phrase */ + Fts3PhraseToken *pToken; /* The token itself */ + Fts3Expr *pRoot; /* Root of NEAR/AND cluster */ + int nOvfl; /* Number of overflow pages to load doclist */ + int iCol; /* The column the token must match */ +}; + +/* +** This function is used to populate an allocated Fts3TokenAndCost array. +** +** If *pRc is not SQLITE_OK when this function is called, it is a no-op. +** Otherwise, if an error occurs during execution, *pRc is set to an +** SQLite error code. +*/ +static void fts3EvalTokenCosts( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Expr *pRoot, /* Root of current AND/NEAR cluster */ + Fts3Expr *pExpr, /* Expression to consider */ + Fts3TokenAndCost **ppTC, /* Write new entries to *(*ppTC)++ */ + Fts3Expr ***ppOr, /* Write new OR root to *(*ppOr)++ */ + int *pRc /* IN/OUT: Error code */ +){ + if( *pRc==SQLITE_OK ){ + if( pExpr->eType==FTSQUERY_PHRASE ){ + Fts3Phrase *pPhrase = pExpr->pPhrase; + int i; + for(i=0; *pRc==SQLITE_OK && i<pPhrase->nToken; i++){ + Fts3TokenAndCost *pTC = (*ppTC)++; + pTC->pPhrase = pPhrase; + pTC->iToken = i; + pTC->pRoot = pRoot; + pTC->pToken = &pPhrase->aToken[i]; + pTC->iCol = pPhrase->iColumn; + *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl); + } + }else if( pExpr->eType!=FTSQUERY_NOT ){ + assert( pExpr->eType==FTSQUERY_OR + || pExpr->eType==FTSQUERY_AND + || pExpr->eType==FTSQUERY_NEAR + ); + assert( pExpr->pLeft && pExpr->pRight ); + if( pExpr->eType==FTSQUERY_OR ){ + pRoot = pExpr->pLeft; + **ppOr = pRoot; + (*ppOr)++; + } + fts3EvalTokenCosts(pCsr, pRoot, pExpr->pLeft, ppTC, ppOr, pRc); + if( pExpr->eType==FTSQUERY_OR ){ + pRoot = pExpr->pRight; + **ppOr = pRoot; + (*ppOr)++; + } + fts3EvalTokenCosts(pCsr, pRoot, pExpr->pRight, ppTC, ppOr, pRc); + } + } +} + +/* +** Determine the average document (row) size in pages. If successful, +** write this value to *pnPage and return SQLITE_OK. Otherwise, return +** an SQLite error code. +** +** The average document size in pages is calculated by first calculating +** determining the average size in bytes, B. If B is less than the amount +** of data that will fit on a single leaf page of an intkey table in +** this database, then the average docsize is 1. Otherwise, it is 1 plus +** the number of overflow pages consumed by a record B bytes in size. +*/ +static int fts3EvalAverageDocsize(Fts3Cursor *pCsr, int *pnPage){ + int rc = SQLITE_OK; + if( pCsr->nRowAvg==0 ){ + /* The average document size, which is required to calculate the cost + ** of each doclist, has not yet been determined. Read the required + ** data from the %_stat table to calculate it. + ** + ** Entry 0 of the %_stat table is a blob containing (nCol+1) FTS3 + ** varints, where nCol is the number of columns in the FTS3 table. + ** The first varint is the number of documents currently stored in + ** the table. The following nCol varints contain the total amount of + ** data stored in all rows of each column of the table, from left + ** to right. + */ + Fts3Table *p = (Fts3Table*)pCsr->base.pVtab; + sqlite3_stmt *pStmt; + sqlite3_int64 nDoc = 0; + sqlite3_int64 nByte = 0; + const char *pEnd; + const char *a; + + rc = sqlite3Fts3SelectDoctotal(p, &pStmt); + if( rc!=SQLITE_OK ) return rc; + a = sqlite3_column_blob(pStmt, 0); + testcase( a==0 ); /* If %_stat.value set to X'' */ + if( a ){ + pEnd = &a[sqlite3_column_bytes(pStmt, 0)]; + a += sqlite3Fts3GetVarintBounded(a, pEnd, &nDoc); + while( a<pEnd ){ + a += sqlite3Fts3GetVarintBounded(a, pEnd, &nByte); + } + } + if( nDoc==0 || nByte==0 ){ + sqlite3_reset(pStmt); + return FTS_CORRUPT_VTAB; + } + + pCsr->nDoc = nDoc; + pCsr->nRowAvg = (int)(((nByte / nDoc) + p->nPgsz) / p->nPgsz); + assert( pCsr->nRowAvg>0 ); + rc = sqlite3_reset(pStmt); + } + + *pnPage = pCsr->nRowAvg; + return rc; +} + +/* +** This function is called to select the tokens (if any) that will be +** deferred. The array aTC[] has already been populated when this is +** called. +** +** This function is called once for each AND/NEAR cluster in the +** expression. Each invocation determines which tokens to defer within +** the cluster with root node pRoot. See comments above the definition +** of struct Fts3TokenAndCost for more details. +** +** If no error occurs, SQLITE_OK is returned and sqlite3Fts3DeferToken() +** called on each token to defer. Otherwise, an SQLite error code is +** returned. +*/ +static int fts3EvalSelectDeferred( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Expr *pRoot, /* Consider tokens with this root node */ + Fts3TokenAndCost *aTC, /* Array of expression tokens and costs */ + int nTC /* Number of entries in aTC[] */ +){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + int nDocSize = 0; /* Number of pages per doc loaded */ + int rc = SQLITE_OK; /* Return code */ + int ii; /* Iterator variable for various purposes */ + int nOvfl = 0; /* Total overflow pages used by doclists */ + int nToken = 0; /* Total number of tokens in cluster */ + + int nMinEst = 0; /* The minimum count for any phrase so far. */ + int nLoad4 = 1; /* (Phrases that will be loaded)^4. */ + + /* Tokens are never deferred for FTS tables created using the content=xxx + ** option. The reason being that it is not guaranteed that the content + ** table actually contains the same data as the index. To prevent this from + ** causing any problems, the deferred token optimization is completely + ** disabled for content=xxx tables. */ + if( pTab->zContentTbl ){ + return SQLITE_OK; + } + + /* Count the tokens in this AND/NEAR cluster. If none of the doclists + ** associated with the tokens spill onto overflow pages, or if there is + ** only 1 token, exit early. No tokens to defer in this case. */ + for(ii=0; ii<nTC; ii++){ + if( aTC[ii].pRoot==pRoot ){ + nOvfl += aTC[ii].nOvfl; + nToken++; + } + } + if( nOvfl==0 || nToken<2 ) return SQLITE_OK; + + /* Obtain the average docsize (in pages). */ + rc = fts3EvalAverageDocsize(pCsr, &nDocSize); + assert( rc!=SQLITE_OK || nDocSize>0 ); + + + /* Iterate through all tokens in this AND/NEAR cluster, in ascending order + ** of the number of overflow pages that will be loaded by the pager layer + ** to retrieve the entire doclist for the token from the full-text index. + ** Load the doclists for tokens that are either: + ** + ** a. The cheapest token in the entire query (i.e. the one visited by the + ** first iteration of this loop), or + ** + ** b. Part of a multi-token phrase. + ** + ** After each token doclist is loaded, merge it with the others from the + ** same phrase and count the number of documents that the merged doclist + ** contains. Set variable "nMinEst" to the smallest number of documents in + ** any phrase doclist for which 1 or more token doclists have been loaded. + ** Let nOther be the number of other phrases for which it is certain that + ** one or more tokens will not be deferred. + ** + ** Then, for each token, defer it if loading the doclist would result in + ** loading N or more overflow pages into memory, where N is computed as: + ** + ** (nMinEst + 4^nOther - 1) / (4^nOther) + */ + for(ii=0; ii<nToken && rc==SQLITE_OK; ii++){ + int iTC; /* Used to iterate through aTC[] array. */ + Fts3TokenAndCost *pTC = 0; /* Set to cheapest remaining token. */ + + /* Set pTC to point to the cheapest remaining token. */ + for(iTC=0; iTC<nTC; iTC++){ + if( aTC[iTC].pToken && aTC[iTC].pRoot==pRoot + && (!pTC || aTC[iTC].nOvfl<pTC->nOvfl) + ){ + pTC = &aTC[iTC]; + } + } + assert( pTC ); + + if( ii && pTC->nOvfl>=((nMinEst+(nLoad4/4)-1)/(nLoad4/4))*nDocSize ){ + /* The number of overflow pages to load for this (and therefore all + ** subsequent) tokens is greater than the estimated number of pages + ** that will be loaded if all subsequent tokens are deferred. + */ + Fts3PhraseToken *pToken = pTC->pToken; + rc = sqlite3Fts3DeferToken(pCsr, pToken, pTC->iCol); + fts3SegReaderCursorFree(pToken->pSegcsr); + pToken->pSegcsr = 0; + }else{ + /* Set nLoad4 to the value of (4^nOther) for the next iteration of the + ** for-loop. Except, limit the value to 2^24 to prevent it from + ** overflowing the 32-bit integer it is stored in. */ + if( ii<12 ) nLoad4 = nLoad4*4; + + if( ii==0 || (pTC->pPhrase->nToken>1 && ii!=nToken-1) ){ + /* Either this is the cheapest token in the entire query, or it is + ** part of a multi-token phrase. Either way, the entire doclist will + ** (eventually) be loaded into memory. It may as well be now. */ + Fts3PhraseToken *pToken = pTC->pToken; + int nList = 0; + char *pList = 0; + rc = fts3TermSelect(pTab, pToken, pTC->iCol, &nList, &pList); + assert( rc==SQLITE_OK || pList==0 ); + if( rc==SQLITE_OK ){ + rc = fts3EvalPhraseMergeToken( + pTab, pTC->pPhrase, pTC->iToken,pList,nList + ); + } + if( rc==SQLITE_OK ){ + int nCount; + nCount = fts3DoclistCountDocids( + pTC->pPhrase->doclist.aAll, pTC->pPhrase->doclist.nAll + ); + if( ii==0 || nCount<nMinEst ) nMinEst = nCount; + } + } + } + pTC->pToken = 0; + } + + return rc; +} + +/* +** This function is called from within the xFilter method. It initializes +** the full-text query currently stored in pCsr->pExpr. To iterate through +** the results of a query, the caller does: +** +** fts3EvalStart(pCsr); +** while( 1 ){ +** fts3EvalNext(pCsr); +** if( pCsr->bEof ) break; +** ... return row pCsr->iPrevId to the caller ... +** } +*/ +static int fts3EvalStart(Fts3Cursor *pCsr){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + int rc = SQLITE_OK; + int nToken = 0; + int nOr = 0; + + /* Allocate a MultiSegReader for each token in the expression. */ + fts3EvalAllocateReaders(pCsr, pCsr->pExpr, &nToken, &nOr, &rc); + + /* Determine which, if any, tokens in the expression should be deferred. */ +#ifndef SQLITE_DISABLE_FTS4_DEFERRED + if( rc==SQLITE_OK && nToken>1 && pTab->bFts4 ){ + Fts3TokenAndCost *aTC; + aTC = (Fts3TokenAndCost *)sqlite3_malloc64( + sizeof(Fts3TokenAndCost) * nToken + + sizeof(Fts3Expr *) * nOr * 2 + ); + + if( !aTC ){ + rc = SQLITE_NOMEM; + }else{ + Fts3Expr **apOr = (Fts3Expr **)&aTC[nToken]; + int ii; + Fts3TokenAndCost *pTC = aTC; + Fts3Expr **ppOr = apOr; + + fts3EvalTokenCosts(pCsr, 0, pCsr->pExpr, &pTC, &ppOr, &rc); + nToken = (int)(pTC-aTC); + nOr = (int)(ppOr-apOr); + + if( rc==SQLITE_OK ){ + rc = fts3EvalSelectDeferred(pCsr, 0, aTC, nToken); + for(ii=0; rc==SQLITE_OK && ii<nOr; ii++){ + rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken); + } + } + + sqlite3_free(aTC); + } + } +#endif + + fts3EvalStartReaders(pCsr, pCsr->pExpr, &rc); + return rc; +} + +/* +** Invalidate the current position list for phrase pPhrase. +*/ +static void fts3EvalInvalidatePoslist(Fts3Phrase *pPhrase){ + if( pPhrase->doclist.bFreeList ){ + sqlite3_free(pPhrase->doclist.pList); + } + pPhrase->doclist.pList = 0; + pPhrase->doclist.nList = 0; + pPhrase->doclist.bFreeList = 0; +} + +/* +** This function is called to edit the position list associated with +** the phrase object passed as the fifth argument according to a NEAR +** condition. For example: +** +** abc NEAR/5 "def ghi" +** +** Parameter nNear is passed the NEAR distance of the expression (5 in +** the example above). When this function is called, *paPoslist points to +** the position list, and *pnToken is the number of phrase tokens in the +** phrase on the other side of the NEAR operator to pPhrase. For example, +** if pPhrase refers to the "def ghi" phrase, then *paPoslist points to +** the position list associated with phrase "abc". +** +** All positions in the pPhrase position list that are not sufficiently +** close to a position in the *paPoslist position list are removed. If this +** leaves 0 positions, zero is returned. Otherwise, non-zero. +** +** Before returning, *paPoslist is set to point to the position lsit +** associated with pPhrase. And *pnToken is set to the number of tokens in +** pPhrase. +*/ +static int fts3EvalNearTrim( + int nNear, /* NEAR distance. As in "NEAR/nNear". */ + char *aTmp, /* Temporary space to use */ + char **paPoslist, /* IN/OUT: Position list */ + int *pnToken, /* IN/OUT: Tokens in phrase of *paPoslist */ + Fts3Phrase *pPhrase /* The phrase object to trim the doclist of */ +){ + int nParam1 = nNear + pPhrase->nToken; + int nParam2 = nNear + *pnToken; + int nNew; + char *p2; + char *pOut; + int res; + + assert( pPhrase->doclist.pList ); + + p2 = pOut = pPhrase->doclist.pList; + res = fts3PoslistNearMerge( + &pOut, aTmp, nParam1, nParam2, paPoslist, &p2 + ); + if( res ){ + nNew = (int)(pOut - pPhrase->doclist.pList) - 1; + assert_fts3_nc( nNew<=pPhrase->doclist.nList && nNew>0 ); + if( nNew>=0 && nNew<=pPhrase->doclist.nList ){ + assert( pPhrase->doclist.pList[nNew]=='\0' ); + memset(&pPhrase->doclist.pList[nNew], 0, pPhrase->doclist.nList - nNew); + pPhrase->doclist.nList = nNew; + } + *paPoslist = pPhrase->doclist.pList; + *pnToken = pPhrase->nToken; + } + + return res; +} + +/* +** This function is a no-op if *pRc is other than SQLITE_OK when it is called. +** Otherwise, it advances the expression passed as the second argument to +** point to the next matching row in the database. Expressions iterate through +** matching rows in docid order. Ascending order if Fts3Cursor.bDesc is zero, +** or descending if it is non-zero. +** +** If an error occurs, *pRc is set to an SQLite error code. Otherwise, if +** successful, the following variables in pExpr are set: +** +** Fts3Expr.bEof (non-zero if EOF - there is no next row) +** Fts3Expr.iDocid (valid if bEof==0. The docid of the next row) +** +** If the expression is of type FTSQUERY_PHRASE, and the expression is not +** at EOF, then the following variables are populated with the position list +** for the phrase for the visited row: +** +** FTs3Expr.pPhrase->doclist.nList (length of pList in bytes) +** FTs3Expr.pPhrase->doclist.pList (pointer to position list) +** +** It says above that this function advances the expression to the next +** matching row. This is usually true, but there are the following exceptions: +** +** 1. Deferred tokens are not taken into account. If a phrase consists +** entirely of deferred tokens, it is assumed to match every row in +** the db. In this case the position-list is not populated at all. +** +** Or, if a phrase contains one or more deferred tokens and one or +** more non-deferred tokens, then the expression is advanced to the +** next possible match, considering only non-deferred tokens. In other +** words, if the phrase is "A B C", and "B" is deferred, the expression +** is advanced to the next row that contains an instance of "A * C", +** where "*" may match any single token. The position list in this case +** is populated as for "A * C" before returning. +** +** 2. NEAR is treated as AND. If the expression is "x NEAR y", it is +** advanced to point to the next row that matches "x AND y". +** +** See sqlite3Fts3EvalTestDeferred() for details on testing if a row is +** really a match, taking into account deferred tokens and NEAR operators. +*/ +static void fts3EvalNextRow( + Fts3Cursor *pCsr, /* FTS Cursor handle */ + Fts3Expr *pExpr, /* Expr. to advance to next matching row */ + int *pRc /* IN/OUT: Error code */ +){ + if( *pRc==SQLITE_OK ){ + int bDescDoclist = pCsr->bDesc; /* Used by DOCID_CMP() macro */ + assert( pExpr->bEof==0 ); + pExpr->bStart = 1; + + switch( pExpr->eType ){ + case FTSQUERY_NEAR: + case FTSQUERY_AND: { + Fts3Expr *pLeft = pExpr->pLeft; + Fts3Expr *pRight = pExpr->pRight; + assert( !pLeft->bDeferred || !pRight->bDeferred ); + + if( pLeft->bDeferred ){ + /* LHS is entirely deferred. So we assume it matches every row. + ** Advance the RHS iterator to find the next row visited. */ + fts3EvalNextRow(pCsr, pRight, pRc); + pExpr->iDocid = pRight->iDocid; + pExpr->bEof = pRight->bEof; + }else if( pRight->bDeferred ){ + /* RHS is entirely deferred. So we assume it matches every row. + ** Advance the LHS iterator to find the next row visited. */ + fts3EvalNextRow(pCsr, pLeft, pRc); + pExpr->iDocid = pLeft->iDocid; + pExpr->bEof = pLeft->bEof; + }else{ + /* Neither the RHS or LHS are deferred. */ + fts3EvalNextRow(pCsr, pLeft, pRc); + fts3EvalNextRow(pCsr, pRight, pRc); + while( !pLeft->bEof && !pRight->bEof && *pRc==SQLITE_OK ){ + sqlite3_int64 iDiff = DOCID_CMP(pLeft->iDocid, pRight->iDocid); + if( iDiff==0 ) break; + if( iDiff<0 ){ + fts3EvalNextRow(pCsr, pLeft, pRc); + }else{ + fts3EvalNextRow(pCsr, pRight, pRc); + } + } + pExpr->iDocid = pLeft->iDocid; + pExpr->bEof = (pLeft->bEof || pRight->bEof); + if( pExpr->eType==FTSQUERY_NEAR && pExpr->bEof ){ + assert( pRight->eType==FTSQUERY_PHRASE ); + if( pRight->pPhrase->doclist.aAll ){ + Fts3Doclist *pDl = &pRight->pPhrase->doclist; + while( *pRc==SQLITE_OK && pRight->bEof==0 ){ + memset(pDl->pList, 0, pDl->nList); + fts3EvalNextRow(pCsr, pRight, pRc); + } + } + if( pLeft->pPhrase && pLeft->pPhrase->doclist.aAll ){ + Fts3Doclist *pDl = &pLeft->pPhrase->doclist; + while( *pRc==SQLITE_OK && pLeft->bEof==0 ){ + memset(pDl->pList, 0, pDl->nList); + fts3EvalNextRow(pCsr, pLeft, pRc); + } + } + pRight->bEof = pLeft->bEof = 1; + } + } + break; + } + + case FTSQUERY_OR: { + Fts3Expr *pLeft = pExpr->pLeft; + Fts3Expr *pRight = pExpr->pRight; + sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid); + + assert_fts3_nc( pLeft->bStart || pLeft->iDocid==pRight->iDocid ); + assert_fts3_nc( pRight->bStart || pLeft->iDocid==pRight->iDocid ); + + if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){ + fts3EvalNextRow(pCsr, pLeft, pRc); + }else if( pLeft->bEof || iCmp>0 ){ + fts3EvalNextRow(pCsr, pRight, pRc); + }else{ + fts3EvalNextRow(pCsr, pLeft, pRc); + fts3EvalNextRow(pCsr, pRight, pRc); + } + + pExpr->bEof = (pLeft->bEof && pRight->bEof); + iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid); + if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){ + pExpr->iDocid = pLeft->iDocid; + }else{ + pExpr->iDocid = pRight->iDocid; + } + + break; + } + + case FTSQUERY_NOT: { + Fts3Expr *pLeft = pExpr->pLeft; + Fts3Expr *pRight = pExpr->pRight; + + if( pRight->bStart==0 ){ + fts3EvalNextRow(pCsr, pRight, pRc); + assert( *pRc!=SQLITE_OK || pRight->bStart ); + } + + fts3EvalNextRow(pCsr, pLeft, pRc); + if( pLeft->bEof==0 ){ + while( !*pRc + && !pRight->bEof + && DOCID_CMP(pLeft->iDocid, pRight->iDocid)>0 + ){ + fts3EvalNextRow(pCsr, pRight, pRc); + } + } + pExpr->iDocid = pLeft->iDocid; + pExpr->bEof = pLeft->bEof; + break; + } + + default: { + Fts3Phrase *pPhrase = pExpr->pPhrase; + fts3EvalInvalidatePoslist(pPhrase); + *pRc = fts3EvalPhraseNext(pCsr, pPhrase, &pExpr->bEof); + pExpr->iDocid = pPhrase->doclist.iDocid; + break; + } + } + } +} + +/* +** If *pRc is not SQLITE_OK, or if pExpr is not the root node of a NEAR +** cluster, then this function returns 1 immediately. +** +** Otherwise, it checks if the current row really does match the NEAR +** expression, using the data currently stored in the position lists +** (Fts3Expr->pPhrase.doclist.pList/nList) for each phrase in the expression. +** +** If the current row is a match, the position list associated with each +** phrase in the NEAR expression is edited in place to contain only those +** phrase instances sufficiently close to their peers to satisfy all NEAR +** constraints. In this case it returns 1. If the NEAR expression does not +** match the current row, 0 is returned. The position lists may or may not +** be edited if 0 is returned. +*/ +static int fts3EvalNearTest(Fts3Expr *pExpr, int *pRc){ + int res = 1; + + /* The following block runs if pExpr is the root of a NEAR query. + ** For example, the query: + ** + ** "w" NEAR "x" NEAR "y" NEAR "z" + ** + ** which is represented in tree form as: + ** + ** | + ** +--NEAR--+ <-- root of NEAR query + ** | | + ** +--NEAR--+ "z" + ** | | + ** +--NEAR--+ "y" + ** | | + ** "w" "x" + ** + ** The right-hand child of a NEAR node is always a phrase. The + ** left-hand child may be either a phrase or a NEAR node. There are + ** no exceptions to this - it's the way the parser in fts3_expr.c works. + */ + if( *pRc==SQLITE_OK + && pExpr->eType==FTSQUERY_NEAR + && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR) + ){ + Fts3Expr *p; + sqlite3_int64 nTmp = 0; /* Bytes of temp space */ + char *aTmp; /* Temp space for PoslistNearMerge() */ + + /* Allocate temporary working space. */ + for(p=pExpr; p->pLeft; p=p->pLeft){ + assert( p->pRight->pPhrase->doclist.nList>0 ); + nTmp += p->pRight->pPhrase->doclist.nList; + } + nTmp += p->pPhrase->doclist.nList; + aTmp = sqlite3_malloc64(nTmp*2); + if( !aTmp ){ + *pRc = SQLITE_NOMEM; + res = 0; + }else{ + char *aPoslist = p->pPhrase->doclist.pList; + int nToken = p->pPhrase->nToken; + + for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){ + Fts3Phrase *pPhrase = p->pRight->pPhrase; + int nNear = p->nNear; + res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase); + } + + aPoslist = pExpr->pRight->pPhrase->doclist.pList; + nToken = pExpr->pRight->pPhrase->nToken; + for(p=pExpr->pLeft; p && res; p=p->pLeft){ + int nNear; + Fts3Phrase *pPhrase; + assert( p->pParent && p->pParent->pLeft==p ); + nNear = p->pParent->nNear; + pPhrase = ( + p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase + ); + res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase); + } + } + + sqlite3_free(aTmp); + } + + return res; +} + +/* +** This function is a helper function for sqlite3Fts3EvalTestDeferred(). +** Assuming no error occurs or has occurred, It returns non-zero if the +** expression passed as the second argument matches the row that pCsr +** currently points to, or zero if it does not. +** +** If *pRc is not SQLITE_OK when this function is called, it is a no-op. +** If an error occurs during execution of this function, *pRc is set to +** the appropriate SQLite error code. In this case the returned value is +** undefined. +*/ +static int fts3EvalTestExpr( + Fts3Cursor *pCsr, /* FTS cursor handle */ + Fts3Expr *pExpr, /* Expr to test. May or may not be root. */ + int *pRc /* IN/OUT: Error code */ +){ + int bHit = 1; /* Return value */ + if( *pRc==SQLITE_OK ){ + switch( pExpr->eType ){ + case FTSQUERY_NEAR: + case FTSQUERY_AND: + bHit = ( + fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc) + && fts3EvalTestExpr(pCsr, pExpr->pRight, pRc) + && fts3EvalNearTest(pExpr, pRc) + ); + + /* If the NEAR expression does not match any rows, zero the doclist for + ** all phrases involved in the NEAR. This is because the snippet(), + ** offsets() and matchinfo() functions are not supposed to recognize + ** any instances of phrases that are part of unmatched NEAR queries. + ** For example if this expression: + ** + ** ... MATCH 'a OR (b NEAR c)' + ** + ** is matched against a row containing: + ** + ** 'a b d e' + ** + ** then any snippet() should ony highlight the "a" term, not the "b" + ** (as "b" is part of a non-matching NEAR clause). + */ + if( bHit==0 + && pExpr->eType==FTSQUERY_NEAR + && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR) + ){ + Fts3Expr *p; + for(p=pExpr; p->pPhrase==0; p=p->pLeft){ + if( p->pRight->iDocid==pCsr->iPrevId ){ + fts3EvalInvalidatePoslist(p->pRight->pPhrase); + } + } + if( p->iDocid==pCsr->iPrevId ){ + fts3EvalInvalidatePoslist(p->pPhrase); + } + } + + break; + + case FTSQUERY_OR: { + int bHit1 = fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc); + int bHit2 = fts3EvalTestExpr(pCsr, pExpr->pRight, pRc); + bHit = bHit1 || bHit2; + break; + } + + case FTSQUERY_NOT: + bHit = ( + fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc) + && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc) + ); + break; + + default: { +#ifndef SQLITE_DISABLE_FTS4_DEFERRED + if( pCsr->pDeferred && (pExpr->bDeferred || ( + pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList + ))){ + Fts3Phrase *pPhrase = pExpr->pPhrase; + if( pExpr->bDeferred ){ + fts3EvalInvalidatePoslist(pPhrase); + } + *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase); + bHit = (pPhrase->doclist.pList!=0); + pExpr->iDocid = pCsr->iPrevId; + }else +#endif + { + bHit = ( + pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId + && pExpr->pPhrase->doclist.nList>0 + ); + } + break; + } + } + } + return bHit; +} + +/* +** This function is called as the second part of each xNext operation when +** iterating through the results of a full-text query. At this point the +** cursor points to a row that matches the query expression, with the +** following caveats: +** +** * Up until this point, "NEAR" operators in the expression have been +** treated as "AND". +** +** * Deferred tokens have not yet been considered. +** +** If *pRc is not SQLITE_OK when this function is called, it immediately +** returns 0. Otherwise, it tests whether or not after considering NEAR +** operators and deferred tokens the current row is still a match for the +** expression. It returns 1 if both of the following are true: +** +** 1. *pRc is SQLITE_OK when this function returns, and +** +** 2. After scanning the current FTS table row for the deferred tokens, +** it is determined that the row does *not* match the query. +** +** Or, if no error occurs and it seems the current row does match the FTS +** query, return 0. +*/ +int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc){ + int rc = *pRc; + int bMiss = 0; + if( rc==SQLITE_OK ){ + + /* If there are one or more deferred tokens, load the current row into + ** memory and scan it to determine the position list for each deferred + ** token. Then, see if this row is really a match, considering deferred + ** tokens and NEAR operators (neither of which were taken into account + ** earlier, by fts3EvalNextRow()). + */ + if( pCsr->pDeferred ){ + rc = fts3CursorSeek(0, pCsr); + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3CacheDeferredDoclists(pCsr); + } + } + bMiss = (0==fts3EvalTestExpr(pCsr, pCsr->pExpr, &rc)); + + /* Free the position-lists accumulated for each deferred token above. */ + sqlite3Fts3FreeDeferredDoclists(pCsr); + *pRc = rc; + } + return (rc==SQLITE_OK && bMiss); +} + +/* +** Advance to the next document that matches the FTS expression in +** Fts3Cursor.pExpr. +*/ +static int fts3EvalNext(Fts3Cursor *pCsr){ + int rc = SQLITE_OK; /* Return Code */ + Fts3Expr *pExpr = pCsr->pExpr; + assert( pCsr->isEof==0 ); + if( pExpr==0 ){ + pCsr->isEof = 1; + }else{ + do { + if( pCsr->isRequireSeek==0 ){ + sqlite3_reset(pCsr->pStmt); + } + assert( sqlite3_data_count(pCsr->pStmt)==0 ); + fts3EvalNextRow(pCsr, pExpr, &rc); + pCsr->isEof = pExpr->bEof; + pCsr->isRequireSeek = 1; + pCsr->isMatchinfoNeeded = 1; + pCsr->iPrevId = pExpr->iDocid; + }while( pCsr->isEof==0 && sqlite3Fts3EvalTestDeferred(pCsr, &rc) ); + } + + /* Check if the cursor is past the end of the docid range specified + ** by Fts3Cursor.iMinDocid/iMaxDocid. If so, set the EOF flag. */ + if( rc==SQLITE_OK && ( + (pCsr->bDesc==0 && pCsr->iPrevId>pCsr->iMaxDocid) + || (pCsr->bDesc!=0 && pCsr->iPrevId<pCsr->iMinDocid) + )){ + pCsr->isEof = 1; + } + + return rc; +} + +/* +** Restart interation for expression pExpr so that the next call to +** fts3EvalNext() visits the first row. Do not allow incremental +** loading or merging of phrase doclists for this iteration. +** +** If *pRc is other than SQLITE_OK when this function is called, it is +** a no-op. If an error occurs within this function, *pRc is set to an +** SQLite error code before returning. +*/ +static void fts3EvalRestart( + Fts3Cursor *pCsr, + Fts3Expr *pExpr, + int *pRc +){ + if( pExpr && *pRc==SQLITE_OK ){ + Fts3Phrase *pPhrase = pExpr->pPhrase; + + if( pPhrase ){ + fts3EvalInvalidatePoslist(pPhrase); + if( pPhrase->bIncr ){ + int i; + for(i=0; i<pPhrase->nToken; i++){ + Fts3PhraseToken *pToken = &pPhrase->aToken[i]; + assert( pToken->pDeferred==0 ); + if( pToken->pSegcsr ){ + sqlite3Fts3MsrIncrRestart(pToken->pSegcsr); + } + } + *pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase); + } + pPhrase->doclist.pNextDocid = 0; + pPhrase->doclist.iDocid = 0; + pPhrase->pOrPoslist = 0; + } + + pExpr->iDocid = 0; + pExpr->bEof = 0; + pExpr->bStart = 0; + + fts3EvalRestart(pCsr, pExpr->pLeft, pRc); + fts3EvalRestart(pCsr, pExpr->pRight, pRc); + } +} + +/* +** After allocating the Fts3Expr.aMI[] array for each phrase in the +** expression rooted at pExpr, the cursor iterates through all rows matched +** by pExpr, calling this function for each row. This function increments +** the values in Fts3Expr.aMI[] according to the position-list currently +** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase +** expression nodes. +*/ +static void fts3EvalUpdateCounts(Fts3Expr *pExpr, int nCol){ + if( pExpr ){ + Fts3Phrase *pPhrase = pExpr->pPhrase; + if( pPhrase && pPhrase->doclist.pList ){ + int iCol = 0; + char *p = pPhrase->doclist.pList; + + do{ + u8 c = 0; + int iCnt = 0; + while( 0xFE & (*p | c) ){ + if( (c&0x80)==0 ) iCnt++; + c = *p++ & 0x80; + } + + /* aMI[iCol*3 + 1] = Number of occurrences + ** aMI[iCol*3 + 2] = Number of rows containing at least one instance + */ + pExpr->aMI[iCol*3 + 1] += iCnt; + pExpr->aMI[iCol*3 + 2] += (iCnt>0); + if( *p==0x00 ) break; + p++; + p += fts3GetVarint32(p, &iCol); + }while( iCol<nCol ); + } + + fts3EvalUpdateCounts(pExpr->pLeft, nCol); + fts3EvalUpdateCounts(pExpr->pRight, nCol); + } +} + +/* +** Expression pExpr must be of type FTSQUERY_PHRASE. +** +** If it is not already allocated and populated, this function allocates and +** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part +** of a NEAR expression, then it also allocates and populates the same array +** for all other phrases that are part of the NEAR expression. +** +** SQLITE_OK is returned if the aMI[] array is successfully allocated and +** populated. Otherwise, if an error occurs, an SQLite error code is returned. +*/ +static int fts3EvalGatherStats( + Fts3Cursor *pCsr, /* Cursor object */ + Fts3Expr *pExpr /* FTSQUERY_PHRASE expression */ +){ + int rc = SQLITE_OK; /* Return code */ + + assert( pExpr->eType==FTSQUERY_PHRASE ); + if( pExpr->aMI==0 ){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + Fts3Expr *pRoot; /* Root of NEAR expression */ + Fts3Expr *p; /* Iterator used for several purposes */ + + sqlite3_int64 iPrevId = pCsr->iPrevId; + sqlite3_int64 iDocid; + u8 bEof; + + /* Find the root of the NEAR expression */ + pRoot = pExpr; + while( pRoot->pParent && pRoot->pParent->eType==FTSQUERY_NEAR ){ + pRoot = pRoot->pParent; + } + iDocid = pRoot->iDocid; + bEof = pRoot->bEof; + assert( pRoot->bStart ); + + /* Allocate space for the aMSI[] array of each FTSQUERY_PHRASE node */ + for(p=pRoot; p; p=p->pLeft){ + Fts3Expr *pE = (p->eType==FTSQUERY_PHRASE?p:p->pRight); + assert( pE->aMI==0 ); + pE->aMI = (u32 *)sqlite3_malloc64(pTab->nColumn * 3 * sizeof(u32)); + if( !pE->aMI ) return SQLITE_NOMEM; + memset(pE->aMI, 0, pTab->nColumn * 3 * sizeof(u32)); + } + + fts3EvalRestart(pCsr, pRoot, &rc); + + while( pCsr->isEof==0 && rc==SQLITE_OK ){ + + do { + /* Ensure the %_content statement is reset. */ + if( pCsr->isRequireSeek==0 ) sqlite3_reset(pCsr->pStmt); + assert( sqlite3_data_count(pCsr->pStmt)==0 ); + + /* Advance to the next document */ + fts3EvalNextRow(pCsr, pRoot, &rc); + pCsr->isEof = pRoot->bEof; + pCsr->isRequireSeek = 1; + pCsr->isMatchinfoNeeded = 1; + pCsr->iPrevId = pRoot->iDocid; + }while( pCsr->isEof==0 + && pRoot->eType==FTSQUERY_NEAR + && sqlite3Fts3EvalTestDeferred(pCsr, &rc) + ); + + if( rc==SQLITE_OK && pCsr->isEof==0 ){ + fts3EvalUpdateCounts(pRoot, pTab->nColumn); + } + } + + pCsr->isEof = 0; + pCsr->iPrevId = iPrevId; + + if( bEof ){ + pRoot->bEof = bEof; + }else{ + /* Caution: pRoot may iterate through docids in ascending or descending + ** order. For this reason, even though it seems more defensive, the + ** do loop can not be written: + ** + ** do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK ); + */ + fts3EvalRestart(pCsr, pRoot, &rc); + do { + fts3EvalNextRow(pCsr, pRoot, &rc); + assert_fts3_nc( pRoot->bEof==0 ); + if( pRoot->bEof ) rc = FTS_CORRUPT_VTAB; + }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK ); + } + } + return rc; +} + +/* +** This function is used by the matchinfo() module to query a phrase +** expression node for the following information: +** +** 1. The total number of occurrences of the phrase in each column of +** the FTS table (considering all rows), and +** +** 2. For each column, the number of rows in the table for which the +** column contains at least one instance of the phrase. +** +** If no error occurs, SQLITE_OK is returned and the values for each column +** written into the array aiOut as follows: +** +** aiOut[iCol*3 + 1] = Number of occurrences +** aiOut[iCol*3 + 2] = Number of rows containing at least one instance +** +** Caveats: +** +** * If a phrase consists entirely of deferred tokens, then all output +** values are set to the number of documents in the table. In other +** words we assume that very common tokens occur exactly once in each +** column of each row of the table. +** +** * If a phrase contains some deferred tokens (and some non-deferred +** tokens), count the potential occurrence identified by considering +** the non-deferred tokens instead of actual phrase occurrences. +** +** * If the phrase is part of a NEAR expression, then only phrase instances +** that meet the NEAR constraint are included in the counts. +*/ +int sqlite3Fts3EvalPhraseStats( + Fts3Cursor *pCsr, /* FTS cursor handle */ + Fts3Expr *pExpr, /* Phrase expression */ + u32 *aiOut /* Array to write results into (see above) */ +){ + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + int rc = SQLITE_OK; + int iCol; + + if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){ + assert( pCsr->nDoc>0 ); + for(iCol=0; iCol<pTab->nColumn; iCol++){ + aiOut[iCol*3 + 1] = (u32)pCsr->nDoc; + aiOut[iCol*3 + 2] = (u32)pCsr->nDoc; + } + }else{ + rc = fts3EvalGatherStats(pCsr, pExpr); + if( rc==SQLITE_OK ){ + assert( pExpr->aMI ); + for(iCol=0; iCol<pTab->nColumn; iCol++){ + aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1]; + aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2]; + } + } + } + + return rc; +} + +/* +** The expression pExpr passed as the second argument to this function +** must be of type FTSQUERY_PHRASE. +** +** The returned value is either NULL or a pointer to a buffer containing +** a position-list indicating the occurrences of the phrase in column iCol +** of the current row. +** +** More specifically, the returned buffer contains 1 varint for each +** occurrence of the phrase in the column, stored using the normal (delta+2) +** compression and is terminated by either an 0x01 or 0x00 byte. For example, +** if the requested column contains "a b X c d X X" and the position-list +** for 'X' is requested, the buffer returned may contain: +** +** 0x04 0x05 0x03 0x01 or 0x04 0x05 0x03 0x00 +** +** This function works regardless of whether or not the phrase is deferred, +** incremental, or neither. +*/ +int sqlite3Fts3EvalPhrasePoslist( + Fts3Cursor *pCsr, /* FTS3 cursor object */ + Fts3Expr *pExpr, /* Phrase to return doclist for */ + int iCol, /* Column to return position list for */ + char **ppOut /* OUT: Pointer to position list */ +){ + Fts3Phrase *pPhrase = pExpr->pPhrase; + Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab; + char *pIter; + int iThis; + sqlite3_int64 iDocid; + + /* If this phrase is applies specifically to some column other than + ** column iCol, return a NULL pointer. */ + *ppOut = 0; + assert( iCol>=0 && iCol<pTab->nColumn ); + if( (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) ){ + return SQLITE_OK; + } + + iDocid = pExpr->iDocid; + pIter = pPhrase->doclist.pList; + if( iDocid!=pCsr->iPrevId || pExpr->bEof ){ + int rc = SQLITE_OK; + int bDescDoclist = pTab->bDescIdx; /* For DOCID_CMP macro */ + int bOr = 0; + u8 bTreeEof = 0; + Fts3Expr *p; /* Used to iterate from pExpr to root */ + Fts3Expr *pNear; /* Most senior NEAR ancestor (or pExpr) */ + int bMatch; + + /* Check if this phrase descends from an OR expression node. If not, + ** return NULL. Otherwise, the entry that corresponds to docid + ** pCsr->iPrevId may lie earlier in the doclist buffer. Or, if the + ** tree that the node is part of has been marked as EOF, but the node + ** itself is not EOF, then it may point to an earlier entry. */ + pNear = pExpr; + for(p=pExpr->pParent; p; p=p->pParent){ + if( p->eType==FTSQUERY_OR ) bOr = 1; + if( p->eType==FTSQUERY_NEAR ) pNear = p; + if( p->bEof ) bTreeEof = 1; + } + if( bOr==0 ) return SQLITE_OK; + + /* This is the descendent of an OR node. In this case we cannot use + ** an incremental phrase. Load the entire doclist for the phrase + ** into memory in this case. */ + if( pPhrase->bIncr ){ + int bEofSave = pNear->bEof; + fts3EvalRestart(pCsr, pNear, &rc); + while( rc==SQLITE_OK && !pNear->bEof ){ + fts3EvalNextRow(pCsr, pNear, &rc); + if( bEofSave==0 && pNear->iDocid==iDocid ) break; + } + assert( rc!=SQLITE_OK || pPhrase->bIncr==0 ); + if( rc==SQLITE_OK && pNear->bEof!=bEofSave ){ + rc = FTS_CORRUPT_VTAB; + } + } + if( bTreeEof ){ + while( rc==SQLITE_OK && !pNear->bEof ){ + fts3EvalNextRow(pCsr, pNear, &rc); + } + } + if( rc!=SQLITE_OK ) return rc; + + bMatch = 1; + for(p=pNear; p; p=p->pLeft){ + u8 bEof = 0; + Fts3Expr *pTest = p; + Fts3Phrase *pPh; + assert( pTest->eType==FTSQUERY_NEAR || pTest->eType==FTSQUERY_PHRASE ); + if( pTest->eType==FTSQUERY_NEAR ) pTest = pTest->pRight; + assert( pTest->eType==FTSQUERY_PHRASE ); + pPh = pTest->pPhrase; + + pIter = pPh->pOrPoslist; + iDocid = pPh->iOrDocid; + if( pCsr->bDesc==bDescDoclist ){ + bEof = !pPh->doclist.nAll || + (pIter >= (pPh->doclist.aAll + pPh->doclist.nAll)); + while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)<0 ) && bEof==0 ){ + sqlite3Fts3DoclistNext( + bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll, + &pIter, &iDocid, &bEof + ); + } + }else{ + bEof = !pPh->doclist.nAll || (pIter && pIter<=pPh->doclist.aAll); + while( (pIter==0 || DOCID_CMP(iDocid, pCsr->iPrevId)>0 ) && bEof==0 ){ + int dummy; + sqlite3Fts3DoclistPrev( + bDescDoclist, pPh->doclist.aAll, pPh->doclist.nAll, + &pIter, &iDocid, &dummy, &bEof + ); + } + } + pPh->pOrPoslist = pIter; + pPh->iOrDocid = iDocid; + if( bEof || iDocid!=pCsr->iPrevId ) bMatch = 0; + } + + if( bMatch ){ + pIter = pPhrase->pOrPoslist; + }else{ + pIter = 0; + } + } + if( pIter==0 ) return SQLITE_OK; + + if( *pIter==0x01 ){ + pIter++; + pIter += fts3GetVarint32(pIter, &iThis); + }else{ + iThis = 0; + } + while( iThis<iCol ){ + fts3ColumnlistCopy(0, &pIter); + if( *pIter==0x00 ) return SQLITE_OK; + pIter++; + pIter += fts3GetVarint32(pIter, &iThis); + } + if( *pIter==0x00 ){ + pIter = 0; + } + + *ppOut = ((iCol==iThis)?pIter:0); + return SQLITE_OK; +} + +/* +** Free all components of the Fts3Phrase structure that were allocated by +** the eval module. Specifically, this means to free: +** +** * the contents of pPhrase->doclist, and +** * any Fts3MultiSegReader objects held by phrase tokens. +*/ +void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){ + if( pPhrase ){ + int i; + sqlite3_free(pPhrase->doclist.aAll); + fts3EvalInvalidatePoslist(pPhrase); + memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist)); + for(i=0; i<pPhrase->nToken; i++){ + fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr); + pPhrase->aToken[i].pSegcsr = 0; + } + } +} + + +/* +** Return SQLITE_CORRUPT_VTAB. +*/ +#ifdef SQLITE_DEBUG +int sqlite3Fts3Corrupt(){ + return SQLITE_CORRUPT_VTAB; +} +#endif + +#if !SQLITE_CORE +/* +** Initialize API pointer table, if required. +*/ +#ifdef _WIN32 +__declspec(dllexport) +#endif +int sqlite3_fts3_init( + sqlite3 *db, + char **pzErrMsg, + const sqlite3_api_routines *pApi +){ + SQLITE_EXTENSION_INIT2(pApi) + return sqlite3Fts3Init(db); +} +#endif + +#endif |