diff options
Diffstat (limited to 'src/third-party/sqlite/ext')
| -rw-r--r-- | src/third-party/sqlite/ext/dbdump.c | 730 | ||||
| -rw-r--r-- | src/third-party/sqlite/ext/series.c | 448 |
2 files changed, 1178 insertions, 0 deletions
diff --git a/src/third-party/sqlite/ext/dbdump.c b/src/third-party/sqlite/ext/dbdump.c new file mode 100644 index 0000000..9d0764d --- /dev/null +++ b/src/third-party/sqlite/ext/dbdump.c @@ -0,0 +1,730 @@ +/* +** 2016-03-13 +** +** 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 file implements a C-language subroutine that converts the content +** of an SQLite database into UTF-8 text SQL statements that can be used +** to exactly recreate the original database. ROWID values are preserved. +** +** A prototype of the implemented subroutine is this: +** +** int sqlite3_db_dump( +** sqlite3 *db, +** const char *zSchema, +** const char *zTable, +** void (*xCallback)(void*, const char*), +** void *pArg +** ); +** +** The db parameter is the database connection. zSchema is the schema within +** that database which is to be dumped. Usually the zSchema is "main" but +** can also be "temp" or any ATTACH-ed database. If zTable is not NULL, then +** only the content of that one table is dumped. If zTable is NULL, then all +** tables are dumped. +** +** The generate text is passed to xCallback() in multiple calls. The second +** argument to xCallback() is a copy of the pArg parameter. The first +** argument is some of the output text that this routine generates. The +** signature to xCallback() is designed to make it compatible with fputs(). +** +** The sqlite3_db_dump() subroutine returns SQLITE_OK on success or some error +** code if it encounters a problem. +** +** If this file is compiled with -DDBDUMP_STANDALONE then a "main()" routine +** is included so that this routine becomes a command-line utility. The +** command-line utility takes two or three arguments which are the name +** of the database file, the schema, and optionally the table, forming the +** first three arguments of a single call to the library routine. +*/ +#include "sqlite3.h" +#include <stdarg.h> +#include <string.h> +#include <ctype.h> + +/* +** The state of the dump process. +*/ +typedef struct DState DState; +struct DState { + sqlite3 *db; /* The database connection */ + int nErr; /* Number of errors seen so far */ + int rc; /* Error code */ + int writableSchema; /* True if in writable_schema mode */ + int (*xCallback)(const char*,void*); /* Send output here */ + void *pArg; /* Argument to xCallback() */ +}; + +/* +** A variable length string to which one can append text. +*/ +typedef struct DText DText; +struct DText { + char *z; /* The text */ + int n; /* Number of bytes of content in z[] */ + int nAlloc; /* Number of bytes allocated to z[] */ +}; + +/* +** Initialize and destroy a DText object +*/ +static void initText(DText *p){ + memset(p, 0, sizeof(*p)); +} +static void freeText(DText *p){ + sqlite3_free(p->z); + initText(p); +} + +/* zIn is either a pointer to a NULL-terminated string in memory obtained +** from malloc(), or a NULL pointer. The string pointed to by zAppend is +** added to zIn, and the result returned in memory obtained from malloc(). +** zIn, if it was not NULL, is freed. +** +** If the third argument, quote, is not '\0', then it is used as a +** quote character for zAppend. +*/ +static void appendText(DText *p, char const *zAppend, char quote){ + int len; + int i; + int nAppend = (int)(strlen(zAppend) & 0x3fffffff); + + len = nAppend+p->n+1; + if( quote ){ + len += 2; + for(i=0; i<nAppend; i++){ + if( zAppend[i]==quote ) len++; + } + } + + if( p->n+len>=p->nAlloc ){ + char *zNew; + p->nAlloc = p->nAlloc*2 + len + 20; + zNew = sqlite3_realloc(p->z, p->nAlloc); + if( zNew==0 ){ + freeText(p); + return; + } + p->z = zNew; + } + + if( quote ){ + char *zCsr = p->z+p->n; + *zCsr++ = quote; + for(i=0; i<nAppend; i++){ + *zCsr++ = zAppend[i]; + if( zAppend[i]==quote ) *zCsr++ = quote; + } + *zCsr++ = quote; + p->n = (int)(zCsr - p->z); + *zCsr = '\0'; + }else{ + memcpy(p->z+p->n, zAppend, nAppend); + p->n += nAppend; + p->z[p->n] = '\0'; + } +} + +/* +** Attempt to determine if identifier zName needs to be quoted, either +** because it contains non-alphanumeric characters, or because it is an +** SQLite keyword. Be conservative in this estimate: When in doubt assume +** that quoting is required. +** +** Return '"' if quoting is required. Return 0 if no quoting is required. +*/ +static char quoteChar(const char *zName){ + int i; + if( !isalpha((unsigned char)zName[0]) && zName[0]!='_' ) return '"'; + for(i=0; zName[i]; i++){ + if( !isalnum((unsigned char)zName[i]) && zName[i]!='_' ) return '"'; + } +#if 0 + return sqlite3_keyword_check(zName, i) ? '"' : 0; +#else + return 0; +#endif +} + + +/* +** Release memory previously allocated by tableColumnList(). +*/ +static void freeColumnList(char **azCol){ + int i; + for(i=1; azCol[i]; i++){ + sqlite3_free(azCol[i]); + } + /* azCol[0] is a static string */ + sqlite3_free(azCol); +} + +/* +** Return a list of pointers to strings which are the names of all +** columns in table zTab. The memory to hold the names is dynamically +** allocated and must be released by the caller using a subsequent call +** to freeColumnList(). +** +** The azCol[0] entry is usually NULL. However, if zTab contains a rowid +** value that needs to be preserved, then azCol[0] is filled in with the +** name of the rowid column. +** +** The first regular column in the table is azCol[1]. The list is terminated +** by an entry with azCol[i]==0. +*/ +static char **tableColumnList(DState *p, const char *zTab){ + char **azCol = 0; + sqlite3_stmt *pStmt = 0; + char *zSql; + int nCol = 0; + int nAlloc = 0; + int nPK = 0; /* Number of PRIMARY KEY columns seen */ + int isIPK = 0; /* True if one PRIMARY KEY column of type INTEGER */ + int preserveRowid = 1; + int rc; + + zSql = sqlite3_mprintf("PRAGMA table_info=%Q", zTab); + if( zSql==0 ) return 0; + rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0); + sqlite3_free(zSql); + if( rc ) return 0; + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + if( nCol>=nAlloc-2 ){ + char **azNew; + nAlloc = nAlloc*2 + nCol + 10; + azNew = sqlite3_realloc64(azCol, nAlloc*sizeof(azCol[0])); + if( azNew==0 ) goto col_oom; + azCol = azNew; + azCol[0] = 0; + } + azCol[++nCol] = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1)); + if( azCol[nCol]==0 ) goto col_oom; + if( sqlite3_column_int(pStmt, 5) ){ + nPK++; + if( nPK==1 + && sqlite3_stricmp((const char*)sqlite3_column_text(pStmt,2), + "INTEGER")==0 + ){ + isIPK = 1; + }else{ + isIPK = 0; + } + } + } + sqlite3_finalize(pStmt); + pStmt = 0; + azCol[nCol+1] = 0; + + /* The decision of whether or not a rowid really needs to be preserved + ** is tricky. We never need to preserve a rowid for a WITHOUT ROWID table + ** or a table with an INTEGER PRIMARY KEY. We are unable to preserve + ** rowids on tables where the rowid is inaccessible because there are other + ** columns in the table named "rowid", "_rowid_", and "oid". + */ + if( isIPK ){ + /* If a single PRIMARY KEY column with type INTEGER was seen, then it + ** might be an alise for the ROWID. But it might also be a WITHOUT ROWID + ** table or a INTEGER PRIMARY KEY DESC column, neither of which are + ** ROWID aliases. To distinguish these cases, check to see if + ** there is a "pk" entry in "PRAGMA index_list". There will be + ** no "pk" index if the PRIMARY KEY really is an alias for the ROWID. + */ + zSql = sqlite3_mprintf("SELECT 1 FROM pragma_index_list(%Q)" + " WHERE origin='pk'", zTab); + if( zSql==0 ) goto col_oom; + rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0); + sqlite3_free(zSql); + if( rc ){ + freeColumnList(azCol); + return 0; + } + rc = sqlite3_step(pStmt); + sqlite3_finalize(pStmt); + pStmt = 0; + preserveRowid = rc==SQLITE_ROW; + } + if( preserveRowid ){ + /* Only preserve the rowid if we can find a name to use for the + ** rowid */ + static char *azRowid[] = { "rowid", "_rowid_", "oid" }; + int i, j; + for(j=0; j<3; j++){ + for(i=1; i<=nCol; i++){ + if( sqlite3_stricmp(azRowid[j],azCol[i])==0 ) break; + } + if( i>nCol ){ + /* At this point, we know that azRowid[j] is not the name of any + ** ordinary column in the table. Verify that azRowid[j] is a valid + ** name for the rowid before adding it to azCol[0]. WITHOUT ROWID + ** tables will fail this last check */ + rc = sqlite3_table_column_metadata(p->db,0,zTab,azRowid[j],0,0,0,0,0); + if( rc==SQLITE_OK ) azCol[0] = azRowid[j]; + break; + } + } + } + return azCol; + +col_oom: + sqlite3_finalize(pStmt); + freeColumnList(azCol); + p->nErr++; + p->rc = SQLITE_NOMEM; + return 0; +} + +/* +** Send mprintf-formatted content to the output callback. +*/ +static void output_formatted(DState *p, const char *zFormat, ...){ + va_list ap; + char *z; + va_start(ap, zFormat); + z = sqlite3_vmprintf(zFormat, ap); + va_end(ap); + p->xCallback(z, p->pArg); + sqlite3_free(z); +} + +/* +** Find a string that is not found anywhere in z[]. Return a pointer +** to that string. +** +** Try to use zA and zB first. If both of those are already found in z[] +** then make up some string and store it in the buffer zBuf. +*/ +static const char *unused_string( + const char *z, /* Result must not appear anywhere in z */ + const char *zA, const char *zB, /* Try these first */ + char *zBuf /* Space to store a generated string */ +){ + unsigned i = 0; + if( strstr(z, zA)==0 ) return zA; + if( strstr(z, zB)==0 ) return zB; + do{ + sqlite3_snprintf(20,zBuf,"(%s%u)", zA, i++); + }while( strstr(z,zBuf)!=0 ); + return zBuf; +} + +/* +** Output the given string as a quoted string using SQL quoting conventions. +** Additionallly , escape the "\n" and "\r" characters so that they do not +** get corrupted by end-of-line translation facilities in some operating +** systems. +*/ +static void output_quoted_escaped_string(DState *p, const char *z){ + int i; + char c; + for(i=0; (c = z[i])!=0 && c!='\'' && c!='\n' && c!='\r'; i++){} + if( c==0 ){ + output_formatted(p,"'%s'",z); + }else{ + const char *zNL = 0; + const char *zCR = 0; + int nNL = 0; + int nCR = 0; + char zBuf1[20], zBuf2[20]; + for(i=0; z[i]; i++){ + if( z[i]=='\n' ) nNL++; + if( z[i]=='\r' ) nCR++; + } + if( nNL ){ + p->xCallback("replace(", p->pArg); + zNL = unused_string(z, "\\n", "\\012", zBuf1); + } + if( nCR ){ + p->xCallback("replace(", p->pArg); + zCR = unused_string(z, "\\r", "\\015", zBuf2); + } + p->xCallback("'", p->pArg); + while( *z ){ + for(i=0; (c = z[i])!=0 && c!='\n' && c!='\r' && c!='\''; i++){} + if( c=='\'' ) i++; + if( i ){ + output_formatted(p, "%.*s", i, z); + z += i; + } + if( c=='\'' ){ + p->xCallback("'", p->pArg); + continue; + } + if( c==0 ){ + break; + } + z++; + if( c=='\n' ){ + p->xCallback(zNL, p->pArg); + continue; + } + p->xCallback(zCR, p->pArg); + } + p->xCallback("'", p->pArg); + if( nCR ){ + output_formatted(p, ",'%s',char(13))", zCR); + } + if( nNL ){ + output_formatted(p, ",'%s',char(10))", zNL); + } + } +} + +/* +** This is an sqlite3_exec callback routine used for dumping the database. +** Each row received by this callback consists of a table name, +** the table type ("index" or "table") and SQL to create the table. +** This routine should print text sufficient to recreate the table. +*/ +static int dump_callback(void *pArg, int nArg, char **azArg, char **azCol){ + int rc; + const char *zTable; + const char *zType; + const char *zSql; + DState *p = (DState*)pArg; + sqlite3_stmt *pStmt; + + (void)azCol; + if( nArg!=3 ) return 1; + zTable = azArg[0]; + zType = azArg[1]; + zSql = azArg[2]; + + if( strcmp(zTable, "sqlite_sequence")==0 ){ + p->xCallback("DELETE FROM sqlite_sequence;\n", p->pArg); + }else if( sqlite3_strglob("sqlite_stat?", zTable)==0 ){ + p->xCallback("ANALYZE sqlite_schema;\n", p->pArg); + }else if( strncmp(zTable, "sqlite_", 7)==0 ){ + return 0; + }else if( strncmp(zSql, "CREATE VIRTUAL TABLE", 20)==0 ){ +#if 0 + if( !p->writableSchema ){ + p->xCallback("PRAGMA writable_schema=ON;\n", p->pArg); + p->writableSchema = 1; + } + output_formatted(p, + "INSERT INTO sqlite_schema(type,name,tbl_name,rootpage,sql)" + "VALUES('table','%q','%q',0,'%q');", + zTable, zTable, zSql); + return 0; +#endif + }else{ + if( sqlite3_strglob("CREATE TABLE ['\"]*", zSql)==0 ){ + p->xCallback("CREATE TABLE IF NOT EXISTS ", p->pArg); + p->xCallback(zSql+13, p->pArg); + }else{ + p->xCallback(zSql, p->pArg); + } + p->xCallback(";\n", p->pArg); + } + + if( strcmp(zType, "table")==0 ){ + DText sSelect; + DText sTable; + char **azTCol; + int i; + int nCol; + + azTCol = tableColumnList(p, zTable); + if( azTCol==0 ) return 0; + + initText(&sTable); + appendText(&sTable, "INSERT INTO ", 0); + + /* Always quote the table name, even if it appears to be pure ascii, + ** in case it is a keyword. Ex: INSERT INTO "table" ... */ + appendText(&sTable, zTable, quoteChar(zTable)); + + /* If preserving the rowid, add a column list after the table name. + ** In other words: "INSERT INTO tab(rowid,a,b,c,...) VALUES(...)" + ** instead of the usual "INSERT INTO tab VALUES(...)". + */ + if( azTCol[0] ){ + appendText(&sTable, "(", 0); + appendText(&sTable, azTCol[0], 0); + for(i=1; azTCol[i]; i++){ + appendText(&sTable, ",", 0); + appendText(&sTable, azTCol[i], quoteChar(azTCol[i])); + } + appendText(&sTable, ")", 0); + } + appendText(&sTable, " VALUES(", 0); + + /* Build an appropriate SELECT statement */ + initText(&sSelect); + appendText(&sSelect, "SELECT ", 0); + if( azTCol[0] ){ + appendText(&sSelect, azTCol[0], 0); + appendText(&sSelect, ",", 0); + } + for(i=1; azTCol[i]; i++){ + appendText(&sSelect, azTCol[i], quoteChar(azTCol[i])); + if( azTCol[i+1] ){ + appendText(&sSelect, ",", 0); + } + } + nCol = i; + if( azTCol[0]==0 ) nCol--; + freeColumnList(azTCol); + appendText(&sSelect, " FROM ", 0); + appendText(&sSelect, zTable, quoteChar(zTable)); + + rc = sqlite3_prepare_v2(p->db, sSelect.z, -1, &pStmt, 0); + if( rc!=SQLITE_OK ){ + p->nErr++; + if( p->rc==SQLITE_OK ) p->rc = rc; + }else{ + while( SQLITE_ROW==sqlite3_step(pStmt) ){ + p->xCallback(sTable.z, p->pArg); + for(i=0; i<nCol; i++){ + if( i ) p->xCallback(",", p->pArg); + switch( sqlite3_column_type(pStmt,i) ){ + case SQLITE_INTEGER: { + output_formatted(p, "%lld", sqlite3_column_int64(pStmt,i)); + break; + } + case SQLITE_FLOAT: { + double r = sqlite3_column_double(pStmt,i); + sqlite3_uint64 ur; + memcpy(&ur,&r,sizeof(r)); + if( ur==0x7ff0000000000000LL ){ + p->xCallback("1e999", p->pArg); + }else if( ur==0xfff0000000000000LL ){ + p->xCallback("-1e999", p->pArg); + }else{ + output_formatted(p, "%!.20g", r); + } + break; + } + case SQLITE_NULL: { + p->xCallback("NULL", p->pArg); + break; + } + case SQLITE_TEXT: { + output_quoted_escaped_string(p, + (const char*)sqlite3_column_text(pStmt,i)); + break; + } + case SQLITE_BLOB: { + int nByte = sqlite3_column_bytes(pStmt,i); + unsigned char *a = (unsigned char*)sqlite3_column_blob(pStmt,i); + int j; + p->xCallback("x'", p->pArg); + for(j=0; j<nByte; j++){ + char zWord[3]; + zWord[0] = "0123456789abcdef"[(a[j]>>4)&15]; + zWord[1] = "0123456789abcdef"[a[j]&15]; + zWord[2] = 0; + p->xCallback(zWord, p->pArg); + } + p->xCallback("'", p->pArg); + break; + } + } + } + p->xCallback(");\n", p->pArg); + } + } + sqlite3_finalize(pStmt); + freeText(&sTable); + freeText(&sSelect); + } + return 0; +} + + +/* +** Execute a query statement that will generate SQL output. Print +** the result columns, comma-separated, on a line and then add a +** semicolon terminator to the end of that line. +** +** If the number of columns is 1 and that column contains text "--" +** then write the semicolon on a separate line. That way, if a +** "--" comment occurs at the end of the statement, the comment +** won't consume the semicolon terminator. +*/ +static void output_sql_from_query( + DState *p, /* Query context */ + const char *zSelect, /* SELECT statement to extract content */ + ... +){ + sqlite3_stmt *pSelect; + int rc; + int nResult; + int i; + const char *z; + char *zSql; + va_list ap; + va_start(ap, zSelect); + zSql = sqlite3_vmprintf(zSelect, ap); + va_end(ap); + if( zSql==0 ){ + p->rc = SQLITE_NOMEM; + p->nErr++; + return; + } + rc = sqlite3_prepare_v2(p->db, zSql, -1, &pSelect, 0); + sqlite3_free(zSql); + if( rc!=SQLITE_OK || !pSelect ){ + output_formatted(p, "/**** ERROR: (%d) %s *****/\n", rc, + sqlite3_errmsg(p->db)); + p->nErr++; + return; + } + rc = sqlite3_step(pSelect); + nResult = sqlite3_column_count(pSelect); + while( rc==SQLITE_ROW ){ + z = (const char*)sqlite3_column_text(pSelect, 0); + p->xCallback(z, p->pArg); + for(i=1; i<nResult; i++){ + p->xCallback(",", p->pArg); + p->xCallback((const char*)sqlite3_column_text(pSelect,i), p->pArg); + } + if( z==0 ) z = ""; + while( z[0] && (z[0]!='-' || z[1]!='-') ) z++; + if( z[0] ){ + p->xCallback("\n;\n", p->pArg); + }else{ + p->xCallback(";\n", p->pArg); + } + rc = sqlite3_step(pSelect); + } + rc = sqlite3_finalize(pSelect); + if( rc!=SQLITE_OK ){ + output_formatted(p, "/**** ERROR: (%d) %s *****/\n", rc, + sqlite3_errmsg(p->db)); + if( (rc&0xff)!=SQLITE_CORRUPT ) p->nErr++; + } +} + +/* +** Run zQuery. Use dump_callback() as the callback routine so that +** the contents of the query are output as SQL statements. +** +** If we get a SQLITE_CORRUPT error, rerun the query after appending +** "ORDER BY rowid DESC" to the end. +*/ +static void run_schema_dump_query( + DState *p, + const char *zQuery, + ... +){ + char *zErr = 0; + char *z; + va_list ap; + va_start(ap, zQuery); + z = sqlite3_vmprintf(zQuery, ap); + va_end(ap); + sqlite3_exec(p->db, z, dump_callback, p, &zErr); + sqlite3_free(z); + if( zErr ){ + output_formatted(p, "/****** %s ******/\n", zErr); + sqlite3_free(zErr); + p->nErr++; + zErr = 0; + } +} + +/* +** Convert an SQLite database into SQL statements that will recreate that +** database. +*/ +int sqlite3_db_dump( + sqlite3 *db, /* The database connection */ + const char *zSchema, /* Which schema to dump. Usually "main". */ + const char *zTable, /* Which table to dump. NULL means everything. */ + int (*xCallback)(const char*,void*), /* Output sent to this callback */ + void *pArg /* Second argument of the callback */ +){ + DState x; + memset(&x, 0, sizeof(x)); + x.rc = sqlite3_exec(db, "BEGIN", 0, 0, 0); + if( x.rc ) return x.rc; + x.db = db; + x.xCallback = xCallback; + x.pArg = pArg; + xCallback("PRAGMA foreign_keys=OFF;\nBEGIN TRANSACTION;\n", pArg); + if( zTable==0 ){ + run_schema_dump_query(&x, + "SELECT name, type, sql FROM \"%w\".sqlite_schema " + "WHERE sql NOT NULL AND type=='table' AND name!='sqlite_sequence'", + zSchema + ); + run_schema_dump_query(&x, + "SELECT name, type, sql FROM \"%w\".sqlite_schema " + "WHERE name=='sqlite_sequence'", zSchema + ); + output_sql_from_query(&x, + "SELECT sql FROM sqlite_schema " + "WHERE sql NOT NULL AND type IN ('index','trigger','view')", 0 + ); + }else{ + run_schema_dump_query(&x, + "SELECT name, type, sql FROM \"%w\".sqlite_schema " + "WHERE tbl_name=%Q COLLATE nocase AND type=='table'" + " AND sql NOT NULL", + zSchema, zTable + ); + output_sql_from_query(&x, + "SELECT sql FROM \"%w\".sqlite_schema " + "WHERE sql NOT NULL" + " AND type IN ('index','trigger','view')" + " AND tbl_name=%Q COLLATE nocase", + zSchema, zTable + ); + } + if( x.writableSchema ){ + xCallback("PRAGMA writable_schema=OFF;\n", pArg); + } + xCallback(x.nErr ? "ROLLBACK; -- due to errors\n" : "COMMIT;\n", pArg); + sqlite3_exec(db, "COMMIT", 0, 0, 0); + return x.rc; +} + + + +/* The generic subroutine is above. The code the follows implements +** the command-line interface. +*/ +#ifdef DBDUMP_STANDALONE +#include <stdio.h> + +/* +** Command-line interface +*/ +int main(int argc, char **argv){ + sqlite3 *db; + const char *zDb; + const char *zSchema; + const char *zTable = 0; + int rc; + + if( argc<2 || argc>4 ){ + fprintf(stderr, "Usage: %s DATABASE ?SCHEMA? ?TABLE?\n", argv[0]); + return 1; + } + zDb = argv[1]; + zSchema = argc>=3 ? argv[2] : "main"; + zTable = argc==4 ? argv[3] : 0; + + rc = sqlite3_open(zDb, &db); + if( rc ){ + fprintf(stderr, "Cannot open \"%s\": %s\n", zDb, sqlite3_errmsg(db)); + sqlite3_close(db); + return 1; + } + rc = sqlite3_db_dump(db, zSchema, zTable, + (int(*)(const char*,void*))fputs, (void*)stdout); + if( rc ){ + fprintf(stderr, "Error: sqlite3_db_dump() returns %d\n", rc); + } + sqlite3_close(db); + return rc!=SQLITE_OK; +} +#endif /* DBDUMP_STANDALONE */ diff --git a/src/third-party/sqlite/ext/series.c b/src/third-party/sqlite/ext/series.c new file mode 100644 index 0000000..4b34f84 --- /dev/null +++ b/src/third-party/sqlite/ext/series.c @@ -0,0 +1,448 @@ +/* +** 2015-08-18 +** +** 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 file demonstrates how to create a table-valued-function using +** a virtual table. This demo implements the generate_series() function +** which gives similar results to the eponymous function in PostgreSQL. +** Examples: +** +** SELECT * FROM generate_series(0,100,5); +** +** The query above returns integers from 0 through 100 counting by steps +** of 5. +** +** SELECT * FROM generate_series(0,100); +** +** Integers from 0 through 100 with a step size of 1. +** +** SELECT * FROM generate_series(20) LIMIT 10; +** +** Integers 20 through 29. +** +** HOW IT WORKS +** +** The generate_series "function" is really a virtual table with the +** following schema: +** +** CREATE TABLE generate_series( +** value, +** start HIDDEN, +** stop HIDDEN, +** step HIDDEN +** ); +** +** Function arguments in queries against this virtual table are translated +** into equality constraints against successive hidden columns. In other +** words, the following pairs of queries are equivalent to each other: +** +** SELECT * FROM generate_series(0,100,5); +** SELECT * FROM generate_series WHERE start=0 AND stop=100 AND step=5; +** +** SELECT * FROM generate_series(0,100); +** SELECT * FROM generate_series WHERE start=0 AND stop=100; +** +** SELECT * FROM generate_series(20) LIMIT 10; +** SELECT * FROM generate_series WHERE start=20 LIMIT 10; +** +** The generate_series virtual table implementation leaves the xCreate method +** set to NULL. This means that it is not possible to do a CREATE VIRTUAL +** TABLE command with "generate_series" as the USING argument. Instead, there +** is a single generate_series virtual table that is always available without +** having to be created first. +** +** The xBestIndex method looks for equality constraints against the hidden +** start, stop, and step columns, and if present, it uses those constraints +** to bound the sequence of generated values. If the equality constraints +** are missing, it uses 0 for start, 4294967295 for stop, and 1 for step. +** xBestIndex returns a small cost when both start and stop are available, +** and a very large cost if either start or stop are unavailable. This +** encourages the query planner to order joins such that the bounds of the +** series are well-defined. +*/ +#include "sqlite3ext.h" +SQLITE_EXTENSION_INIT1 +#include <assert.h> +#include <string.h> + +#ifndef SQLITE_OMIT_VIRTUALTABLE + + +/* series_cursor is a subclass of sqlite3_vtab_cursor which will +** serve as the underlying representation of a cursor that scans +** over rows of the result +*/ +typedef struct series_cursor series_cursor; +struct series_cursor { + sqlite3_vtab_cursor base; /* Base class - must be first */ + int isDesc; /* True to count down rather than up */ + sqlite3_int64 iRowid; /* The rowid */ + sqlite3_int64 iValue; /* Current value ("value") */ + sqlite3_int64 mnValue; /* Mimimum value ("start") */ + sqlite3_int64 mxValue; /* Maximum value ("stop") */ + sqlite3_int64 iStep; /* Increment ("step") */ +}; + +/* +** The seriesConnect() method is invoked to create a new +** series_vtab that describes the generate_series virtual table. +** +** Think of this routine as the constructor for series_vtab objects. +** +** All this routine needs to do is: +** +** (1) Allocate the series_vtab object and initialize all fields. +** +** (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the +** result set of queries against generate_series will look like. +*/ +static int seriesConnect( + sqlite3 *db, + void *pUnused, + int argcUnused, const char *const*argvUnused, + sqlite3_vtab **ppVtab, + char **pzErrUnused +){ + sqlite3_vtab *pNew; + int rc; + +/* Column numbers */ +#define SERIES_COLUMN_VALUE 0 +#define SERIES_COLUMN_START 1 +#define SERIES_COLUMN_STOP 2 +#define SERIES_COLUMN_STEP 3 + + (void)pUnused; + (void)argcUnused; + (void)argvUnused; + (void)pzErrUnused; + rc = sqlite3_declare_vtab(db, + "CREATE TABLE x(value,start hidden,stop hidden,step hidden)"); + if( rc==SQLITE_OK ){ + pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) ); + if( pNew==0 ) return SQLITE_NOMEM; + memset(pNew, 0, sizeof(*pNew)); +#ifdef SQLITE_VTAB_INNOCUOUS + sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS); +#endif + } + return rc; +} + +/* +** This method is the destructor for series_cursor objects. +*/ +static int seriesDisconnect(sqlite3_vtab *pVtab){ + sqlite3_free(pVtab); + return SQLITE_OK; +} + +/* +** Constructor for a new series_cursor object. +*/ +static int seriesOpen(sqlite3_vtab *pUnused, sqlite3_vtab_cursor **ppCursor){ + series_cursor *pCur; + (void)pUnused; + pCur = sqlite3_malloc( sizeof(*pCur) ); + if( pCur==0 ) return SQLITE_NOMEM; + memset(pCur, 0, sizeof(*pCur)); + *ppCursor = &pCur->base; + return SQLITE_OK; +} + +/* +** Destructor for a series_cursor. +*/ +static int seriesClose(sqlite3_vtab_cursor *cur){ + sqlite3_free(cur); + return SQLITE_OK; +} + + +/* +** Advance a series_cursor to its next row of output. +*/ +static int seriesNext(sqlite3_vtab_cursor *cur){ + series_cursor *pCur = (series_cursor*)cur; + if( pCur->isDesc ){ + pCur->iValue -= pCur->iStep; + }else{ + pCur->iValue += pCur->iStep; + } + pCur->iRowid++; + return SQLITE_OK; +} + +/* +** Return values of columns for the row at which the series_cursor +** is currently pointing. +*/ +static int seriesColumn( + sqlite3_vtab_cursor *cur, /* The cursor */ + sqlite3_context *ctx, /* First argument to sqlite3_result_...() */ + int i /* Which column to return */ +){ + series_cursor *pCur = (series_cursor*)cur; + sqlite3_int64 x = 0; + switch( i ){ + case SERIES_COLUMN_START: x = pCur->mnValue; break; + case SERIES_COLUMN_STOP: x = pCur->mxValue; break; + case SERIES_COLUMN_STEP: x = pCur->iStep; break; + default: x = pCur->iValue; break; + } + sqlite3_result_int64(ctx, x); + return SQLITE_OK; +} + +/* +** Return the rowid for the current row. In this implementation, the +** first row returned is assigned rowid value 1, and each subsequent +** row a value 1 more than that of the previous. +*/ +static int seriesRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ + series_cursor *pCur = (series_cursor*)cur; + *pRowid = pCur->iRowid; + return SQLITE_OK; +} + +/* +** Return TRUE if the cursor has been moved off of the last +** row of output. +*/ +static int seriesEof(sqlite3_vtab_cursor *cur){ + series_cursor *pCur = (series_cursor*)cur; + if( pCur->isDesc ){ + return pCur->iValue < pCur->mnValue; + }else{ + return pCur->iValue > pCur->mxValue; + } +} + +/* True to cause run-time checking of the start=, stop=, and/or step= +** parameters. The only reason to do this is for testing the +** constraint checking logic for virtual tables in the SQLite core. +*/ +#ifndef SQLITE_SERIES_CONSTRAINT_VERIFY +# define SQLITE_SERIES_CONSTRAINT_VERIFY 0 +#endif + +/* +** This method is called to "rewind" the series_cursor object back +** to the first row of output. This method is always called at least +** once prior to any call to seriesColumn() or seriesRowid() or +** seriesEof(). +** +** The query plan selected by seriesBestIndex is passed in the idxNum +** parameter. (idxStr is not used in this implementation.) idxNum +** is a bitmask showing which constraints are available: +** +** 1: start=VALUE +** 2: stop=VALUE +** 4: step=VALUE +** +** Also, if bit 8 is set, that means that the series should be output +** in descending order rather than in ascending order. If bit 16 is +** set, then output must appear in ascending order. +** +** This routine should initialize the cursor and position it so that it +** is pointing at the first row, or pointing off the end of the table +** (so that seriesEof() will return true) if the table is empty. +*/ +static int seriesFilter( + sqlite3_vtab_cursor *pVtabCursor, + int idxNum, const char *idxStrUnused, + int argc, sqlite3_value **argv +){ + series_cursor *pCur = (series_cursor *)pVtabCursor; + int i = 0; + (void)idxStrUnused; + if( idxNum & 1 ){ + pCur->mnValue = sqlite3_value_int64(argv[i++]); + }else{ + pCur->mnValue = 0; + } + if( idxNum & 2 ){ + pCur->mxValue = sqlite3_value_int64(argv[i++]); + }else{ + pCur->mxValue = 0xffffffff; + } + if( idxNum & 4 ){ + pCur->iStep = sqlite3_value_int64(argv[i++]); + if( pCur->iStep==0 ){ + pCur->iStep = 1; + }else if( pCur->iStep<0 ){ + pCur->iStep = -pCur->iStep; + if( (idxNum & 16)==0 ) idxNum |= 8; + } + }else{ + pCur->iStep = 1; + } + for(i=0; i<argc; i++){ + if( sqlite3_value_type(argv[i])==SQLITE_NULL ){ + /* If any of the constraints have a NULL value, then return no rows. + ** See ticket https://www.sqlite.org/src/info/fac496b61722daf2 */ + pCur->mnValue = 1; + pCur->mxValue = 0; + break; + } + } + if( idxNum & 8 ){ + pCur->isDesc = 1; + pCur->iValue = pCur->mxValue; + if( pCur->iStep>0 ){ + pCur->iValue -= (pCur->mxValue - pCur->mnValue)%pCur->iStep; + } + }else{ + pCur->isDesc = 0; + pCur->iValue = pCur->mnValue; + } + pCur->iRowid = 1; + return SQLITE_OK; +} + +/* +** SQLite will invoke this method one or more times while planning a query +** that uses the generate_series virtual table. This routine needs to create +** a query plan for each invocation and compute an estimated cost for that +** plan. +** +** In this implementation idxNum is used to represent the +** query plan. idxStr is unused. +** +** The query plan is represented by bits in idxNum: +** +** (1) start = $value -- constraint exists +** (2) stop = $value -- constraint exists +** (4) step = $value -- constraint exists +** (8) output in descending order +*/ +static int seriesBestIndex( + sqlite3_vtab *vtab, + sqlite3_index_info *pIdxInfo +){ + int i, j; /* Loop over constraints */ + int idxNum = 0; /* The query plan bitmask */ + int unusableMask = 0; /* Mask of unusable constraints */ + int nArg = 0; /* Number of arguments that seriesFilter() expects */ + int aIdx[3]; /* Constraints on start, stop, and step */ + const struct sqlite3_index_constraint *pConstraint; + + /* This implementation assumes that the start, stop, and step columns + ** are the last three columns in the virtual table. */ + assert( SERIES_COLUMN_STOP == SERIES_COLUMN_START+1 ); + assert( SERIES_COLUMN_STEP == SERIES_COLUMN_START+2 ); + aIdx[0] = aIdx[1] = aIdx[2] = -1; + pConstraint = pIdxInfo->aConstraint; + for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){ + int iCol; /* 0 for start, 1 for stop, 2 for step */ + int iMask; /* bitmask for those column */ + if( pConstraint->iColumn<SERIES_COLUMN_START ) continue; + iCol = pConstraint->iColumn - SERIES_COLUMN_START; + assert( iCol>=0 && iCol<=2 ); + iMask = 1 << iCol; + if( pConstraint->usable==0 ){ + unusableMask |= iMask; + continue; + }else if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){ + idxNum |= iMask; + aIdx[iCol] = i; + } + } + for(i=0; i<3; i++){ + if( (j = aIdx[i])>=0 ){ + pIdxInfo->aConstraintUsage[j].argvIndex = ++nArg; + pIdxInfo->aConstraintUsage[j].omit = !SQLITE_SERIES_CONSTRAINT_VERIFY; + } + } + if( (unusableMask & ~idxNum)!=0 ){ + /* The start, stop, and step columns are inputs. Therefore if there + ** are unusable constraints on any of start, stop, or step then + ** this plan is unusable */ + return SQLITE_CONSTRAINT; + } + if( (idxNum & 3)==3 ){ + /* Both start= and stop= boundaries are available. This is the + ** the preferred case */ + pIdxInfo->estimatedCost = (double)(2 - ((idxNum&4)!=0)); + pIdxInfo->estimatedRows = 1000; + if( pIdxInfo->nOrderBy==1 ){ + if( pIdxInfo->aOrderBy[0].desc ){ + idxNum |= 8; + }else{ + idxNum |= 16; + } + pIdxInfo->orderByConsumed = 1; + } + }else{ + if (!(idxNum & 1)) { + vtab->zErrMsg = sqlite3_mprintf("the start parameter is required"); + } else { + vtab->zErrMsg = sqlite3_mprintf("the stop parameter is required"); + } + return SQLITE_ERROR; + } + pIdxInfo->idxNum = idxNum; + return SQLITE_OK; +} + +/* +** This following structure defines all the methods for the +** generate_series virtual table. +*/ +static sqlite3_module seriesModule = { + 0, /* iVersion */ + 0, /* xCreate */ + seriesConnect, /* xConnect */ + seriesBestIndex, /* xBestIndex */ + seriesDisconnect, /* xDisconnect */ + 0, /* xDestroy */ + seriesOpen, /* xOpen - open a cursor */ + seriesClose, /* xClose - close a cursor */ + seriesFilter, /* xFilter - configure scan constraints */ + seriesNext, /* xNext - advance a cursor */ + seriesEof, /* xEof - check for end of scan */ + seriesColumn, /* xColumn - read data */ + seriesRowid, /* xRowid - read data */ + 0, /* xUpdate */ + 0, /* xBegin */ + 0, /* xSync */ + 0, /* xCommit */ + 0, /* xRollback */ + 0, /* xFindMethod */ + 0, /* xRename */ + 0, /* xSavepoint */ + 0, /* xRelease */ + 0, /* xRollbackTo */ + 0 /* xShadowName */ +}; + +#endif /* SQLITE_OMIT_VIRTUALTABLE */ + +#ifdef _WIN32 +__declspec(dllexport) +#endif +int sqlite3_series_init( + sqlite3 *db, + char **pzErrMsg, + const sqlite3_api_routines *pApi +){ + int rc = SQLITE_OK; + SQLITE_EXTENSION_INIT2(pApi); +#ifndef SQLITE_OMIT_VIRTUALTABLE + if( sqlite3_libversion_number()<3008012 ){ + *pzErrMsg = sqlite3_mprintf( + "generate_series() requires SQLite 3.8.12 or later"); + return SQLITE_ERROR; + } + rc = sqlite3_create_module(db, "generate_series", &seriesModule, 0); +#endif + return rc; +} |