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Diffstat (limited to '')
| -rw-r--r-- | ext/fts3/fts3_expr.c | 1293 |
1 files changed, 1293 insertions, 0 deletions
diff --git a/ext/fts3/fts3_expr.c b/ext/fts3/fts3_expr.c new file mode 100644 index 0000000..ea8167c --- /dev/null +++ b/ext/fts3/fts3_expr.c @@ -0,0 +1,1293 @@ +/* +** 2008 Nov 28 +** +** 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 module contains code that implements a parser for fts3 query strings +** (the right-hand argument to the MATCH operator). Because the supported +** syntax is relatively simple, the whole tokenizer/parser system is +** hand-coded. +*/ +#include "fts3Int.h" +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) + +/* +** By default, this module parses the legacy syntax that has been +** traditionally used by fts3. Or, if SQLITE_ENABLE_FTS3_PARENTHESIS +** is defined, then it uses the new syntax. The differences between +** the new and the old syntaxes are: +** +** a) The new syntax supports parenthesis. The old does not. +** +** b) The new syntax supports the AND and NOT operators. The old does not. +** +** c) The old syntax supports the "-" token qualifier. This is not +** supported by the new syntax (it is replaced by the NOT operator). +** +** d) When using the old syntax, the OR operator has a greater precedence +** than an implicit AND. When using the new, both implicity and explicit +** AND operators have a higher precedence than OR. +** +** If compiled with SQLITE_TEST defined, then this module exports the +** symbol "int sqlite3_fts3_enable_parentheses". Setting this variable +** to zero causes the module to use the old syntax. If it is set to +** non-zero the new syntax is activated. This is so both syntaxes can +** be tested using a single build of testfixture. +** +** The following describes the syntax supported by the fts3 MATCH +** operator in a similar format to that used by the lemon parser +** generator. This module does not use actually lemon, it uses a +** custom parser. +** +** query ::= andexpr (OR andexpr)*. +** +** andexpr ::= notexpr (AND? notexpr)*. +** +** notexpr ::= nearexpr (NOT nearexpr|-TOKEN)*. +** notexpr ::= LP query RP. +** +** nearexpr ::= phrase (NEAR distance_opt nearexpr)*. +** +** distance_opt ::= . +** distance_opt ::= / INTEGER. +** +** phrase ::= TOKEN. +** phrase ::= COLUMN:TOKEN. +** phrase ::= "TOKEN TOKEN TOKEN...". +*/ + +#ifdef SQLITE_TEST +int sqlite3_fts3_enable_parentheses = 0; +#else +# ifdef SQLITE_ENABLE_FTS3_PARENTHESIS +# define sqlite3_fts3_enable_parentheses 1 +# else +# define sqlite3_fts3_enable_parentheses 0 +# endif +#endif + +/* +** Default span for NEAR operators. +*/ +#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10 + +#include <string.h> +#include <assert.h> + +/* +** isNot: +** This variable is used by function getNextNode(). When getNextNode() is +** called, it sets ParseContext.isNot to true if the 'next node' is a +** FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the +** FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to +** zero. +*/ +typedef struct ParseContext ParseContext; +struct ParseContext { + sqlite3_tokenizer *pTokenizer; /* Tokenizer module */ + int iLangid; /* Language id used with tokenizer */ + const char **azCol; /* Array of column names for fts3 table */ + int bFts4; /* True to allow FTS4-only syntax */ + int nCol; /* Number of entries in azCol[] */ + int iDefaultCol; /* Default column to query */ + int isNot; /* True if getNextNode() sees a unary - */ + sqlite3_context *pCtx; /* Write error message here */ + int nNest; /* Number of nested brackets */ +}; + +/* +** This function is equivalent to the standard isspace() function. +** +** The standard isspace() can be awkward to use safely, because although it +** is defined to accept an argument of type int, its behavior when passed +** an integer that falls outside of the range of the unsigned char type +** is undefined (and sometimes, "undefined" means segfault). This wrapper +** is defined to accept an argument of type char, and always returns 0 for +** any values that fall outside of the range of the unsigned char type (i.e. +** negative values). +*/ +static int fts3isspace(char c){ + return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f'; +} + +/* +** Allocate nByte bytes of memory using sqlite3_malloc(). If successful, +** zero the memory before returning a pointer to it. If unsuccessful, +** return NULL. +*/ +void *sqlite3Fts3MallocZero(sqlite3_int64 nByte){ + void *pRet = sqlite3_malloc64(nByte); + if( pRet ) memset(pRet, 0, nByte); + return pRet; +} + +int sqlite3Fts3OpenTokenizer( + sqlite3_tokenizer *pTokenizer, + int iLangid, + const char *z, + int n, + sqlite3_tokenizer_cursor **ppCsr +){ + sqlite3_tokenizer_module const *pModule = pTokenizer->pModule; + sqlite3_tokenizer_cursor *pCsr = 0; + int rc; + + rc = pModule->xOpen(pTokenizer, z, n, &pCsr); + assert( rc==SQLITE_OK || pCsr==0 ); + if( rc==SQLITE_OK ){ + pCsr->pTokenizer = pTokenizer; + if( pModule->iVersion>=1 ){ + rc = pModule->xLanguageid(pCsr, iLangid); + if( rc!=SQLITE_OK ){ + pModule->xClose(pCsr); + pCsr = 0; + } + } + } + *ppCsr = pCsr; + return rc; +} + +/* +** Function getNextNode(), which is called by fts3ExprParse(), may itself +** call fts3ExprParse(). So this forward declaration is required. +*/ +static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *); + +/* +** Extract the next token from buffer z (length n) using the tokenizer +** and other information (column names etc.) in pParse. Create an Fts3Expr +** structure of type FTSQUERY_PHRASE containing a phrase consisting of this +** single token and set *ppExpr to point to it. If the end of the buffer is +** reached before a token is found, set *ppExpr to zero. It is the +** responsibility of the caller to eventually deallocate the allocated +** Fts3Expr structure (if any) by passing it to sqlite3_free(). +** +** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation +** fails. +*/ +static int getNextToken( + ParseContext *pParse, /* fts3 query parse context */ + int iCol, /* Value for Fts3Phrase.iColumn */ + const char *z, int n, /* Input string */ + Fts3Expr **ppExpr, /* OUT: expression */ + int *pnConsumed /* OUT: Number of bytes consumed */ +){ + sqlite3_tokenizer *pTokenizer = pParse->pTokenizer; + sqlite3_tokenizer_module const *pModule = pTokenizer->pModule; + int rc; + sqlite3_tokenizer_cursor *pCursor; + Fts3Expr *pRet = 0; + int i = 0; + + /* Set variable i to the maximum number of bytes of input to tokenize. */ + for(i=0; i<n; i++){ + if( sqlite3_fts3_enable_parentheses && (z[i]=='(' || z[i]==')') ) break; + if( z[i]=='"' ) break; + } + + *pnConsumed = i; + rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, i, &pCursor); + if( rc==SQLITE_OK ){ + const char *zToken; + int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0; + sqlite3_int64 nByte; /* total space to allocate */ + + rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition); + if( rc==SQLITE_OK ){ + nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken; + pRet = (Fts3Expr *)sqlite3Fts3MallocZero(nByte); + if( !pRet ){ + rc = SQLITE_NOMEM; + }else{ + pRet->eType = FTSQUERY_PHRASE; + pRet->pPhrase = (Fts3Phrase *)&pRet[1]; + pRet->pPhrase->nToken = 1; + pRet->pPhrase->iColumn = iCol; + pRet->pPhrase->aToken[0].n = nToken; + pRet->pPhrase->aToken[0].z = (char *)&pRet->pPhrase[1]; + memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken); + + if( iEnd<n && z[iEnd]=='*' ){ + pRet->pPhrase->aToken[0].isPrefix = 1; + iEnd++; + } + + while( 1 ){ + if( !sqlite3_fts3_enable_parentheses + && iStart>0 && z[iStart-1]=='-' + ){ + pParse->isNot = 1; + iStart--; + }else if( pParse->bFts4 && iStart>0 && z[iStart-1]=='^' ){ + pRet->pPhrase->aToken[0].bFirst = 1; + iStart--; + }else{ + break; + } + } + + } + *pnConsumed = iEnd; + }else if( i && rc==SQLITE_DONE ){ + rc = SQLITE_OK; + } + + pModule->xClose(pCursor); + } + + *ppExpr = pRet; + return rc; +} + + +/* +** Enlarge a memory allocation. If an out-of-memory allocation occurs, +** then free the old allocation. +*/ +static void *fts3ReallocOrFree(void *pOrig, sqlite3_int64 nNew){ + void *pRet = sqlite3_realloc64(pOrig, nNew); + if( !pRet ){ + sqlite3_free(pOrig); + } + return pRet; +} + +/* +** Buffer zInput, length nInput, contains the contents of a quoted string +** that appeared as part of an fts3 query expression. Neither quote character +** is included in the buffer. This function attempts to tokenize the entire +** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE +** containing the results. +** +** If successful, SQLITE_OK is returned and *ppExpr set to point at the +** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory +** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set +** to 0. +*/ +static int getNextString( + ParseContext *pParse, /* fts3 query parse context */ + const char *zInput, int nInput, /* Input string */ + Fts3Expr **ppExpr /* OUT: expression */ +){ + sqlite3_tokenizer *pTokenizer = pParse->pTokenizer; + sqlite3_tokenizer_module const *pModule = pTokenizer->pModule; + int rc; + Fts3Expr *p = 0; + sqlite3_tokenizer_cursor *pCursor = 0; + char *zTemp = 0; + int nTemp = 0; + + const int nSpace = sizeof(Fts3Expr) + sizeof(Fts3Phrase); + int nToken = 0; + + /* The final Fts3Expr data structure, including the Fts3Phrase, + ** Fts3PhraseToken structures token buffers are all stored as a single + ** allocation so that the expression can be freed with a single call to + ** sqlite3_free(). Setting this up requires a two pass approach. + ** + ** The first pass, in the block below, uses a tokenizer cursor to iterate + ** through the tokens in the expression. This pass uses fts3ReallocOrFree() + ** to assemble data in two dynamic buffers: + ** + ** Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase + ** structure, followed by the array of Fts3PhraseToken + ** structures. This pass only populates the Fts3PhraseToken array. + ** + ** Buffer zTemp: Contains copies of all tokens. + ** + ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below, + ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase + ** structures. + */ + rc = sqlite3Fts3OpenTokenizer( + pTokenizer, pParse->iLangid, zInput, nInput, &pCursor); + if( rc==SQLITE_OK ){ + int ii; + for(ii=0; rc==SQLITE_OK; ii++){ + const char *zByte; + int nByte = 0, iBegin = 0, iEnd = 0, iPos = 0; + rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos); + if( rc==SQLITE_OK ){ + Fts3PhraseToken *pToken; + + p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken)); + if( !p ) goto no_mem; + + zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte); + if( !zTemp ) goto no_mem; + + assert( nToken==ii ); + pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii]; + memset(pToken, 0, sizeof(Fts3PhraseToken)); + + memcpy(&zTemp[nTemp], zByte, nByte); + nTemp += nByte; + + pToken->n = nByte; + pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*'); + pToken->bFirst = (iBegin>0 && zInput[iBegin-1]=='^'); + nToken = ii+1; + } + } + + pModule->xClose(pCursor); + pCursor = 0; + } + + if( rc==SQLITE_DONE ){ + int jj; + char *zBuf = 0; + + p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp); + if( !p ) goto no_mem; + memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p); + p->eType = FTSQUERY_PHRASE; + p->pPhrase = (Fts3Phrase *)&p[1]; + p->pPhrase->iColumn = pParse->iDefaultCol; + p->pPhrase->nToken = nToken; + + zBuf = (char *)&p->pPhrase->aToken[nToken]; + if( zTemp ){ + memcpy(zBuf, zTemp, nTemp); + sqlite3_free(zTemp); + }else{ + assert( nTemp==0 ); + } + + for(jj=0; jj<p->pPhrase->nToken; jj++){ + p->pPhrase->aToken[jj].z = zBuf; + zBuf += p->pPhrase->aToken[jj].n; + } + rc = SQLITE_OK; + } + + *ppExpr = p; + return rc; +no_mem: + + if( pCursor ){ + pModule->xClose(pCursor); + } + sqlite3_free(zTemp); + sqlite3_free(p); + *ppExpr = 0; + return SQLITE_NOMEM; +} + +/* +** The output variable *ppExpr is populated with an allocated Fts3Expr +** structure, or set to 0 if the end of the input buffer is reached. +** +** Returns an SQLite error code. SQLITE_OK if everything works, SQLITE_NOMEM +** if a malloc failure occurs, or SQLITE_ERROR if a parse error is encountered. +** If SQLITE_ERROR is returned, pContext is populated with an error message. +*/ +static int getNextNode( + ParseContext *pParse, /* fts3 query parse context */ + const char *z, int n, /* Input string */ + Fts3Expr **ppExpr, /* OUT: expression */ + int *pnConsumed /* OUT: Number of bytes consumed */ +){ + static const struct Fts3Keyword { + char *z; /* Keyword text */ + unsigned char n; /* Length of the keyword */ + unsigned char parenOnly; /* Only valid in paren mode */ + unsigned char eType; /* Keyword code */ + } aKeyword[] = { + { "OR" , 2, 0, FTSQUERY_OR }, + { "AND", 3, 1, FTSQUERY_AND }, + { "NOT", 3, 1, FTSQUERY_NOT }, + { "NEAR", 4, 0, FTSQUERY_NEAR } + }; + int ii; + int iCol; + int iColLen; + int rc; + Fts3Expr *pRet = 0; + + const char *zInput = z; + int nInput = n; + + pParse->isNot = 0; + + /* Skip over any whitespace before checking for a keyword, an open or + ** close bracket, or a quoted string. + */ + while( nInput>0 && fts3isspace(*zInput) ){ + nInput--; + zInput++; + } + if( nInput==0 ){ + return SQLITE_DONE; + } + + /* See if we are dealing with a keyword. */ + for(ii=0; ii<(int)(sizeof(aKeyword)/sizeof(struct Fts3Keyword)); ii++){ + const struct Fts3Keyword *pKey = &aKeyword[ii]; + + if( (pKey->parenOnly & ~sqlite3_fts3_enable_parentheses)!=0 ){ + continue; + } + + if( nInput>=pKey->n && 0==memcmp(zInput, pKey->z, pKey->n) ){ + int nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM; + int nKey = pKey->n; + char cNext; + + /* If this is a "NEAR" keyword, check for an explicit nearness. */ + if( pKey->eType==FTSQUERY_NEAR ){ + assert( nKey==4 ); + if( zInput[4]=='/' && zInput[5]>='0' && zInput[5]<='9' ){ + nKey += 1+sqlite3Fts3ReadInt(&zInput[nKey+1], &nNear); + } + } + + /* At this point this is probably a keyword. But for that to be true, + ** the next byte must contain either whitespace, an open or close + ** parenthesis, a quote character, or EOF. + */ + cNext = zInput[nKey]; + if( fts3isspace(cNext) + || cNext=='"' || cNext=='(' || cNext==')' || cNext==0 + ){ + pRet = (Fts3Expr *)sqlite3Fts3MallocZero(sizeof(Fts3Expr)); + if( !pRet ){ + return SQLITE_NOMEM; + } + pRet->eType = pKey->eType; + pRet->nNear = nNear; + *ppExpr = pRet; + *pnConsumed = (int)((zInput - z) + nKey); + return SQLITE_OK; + } + + /* Turns out that wasn't a keyword after all. This happens if the + ** user has supplied a token such as "ORacle". Continue. + */ + } + } + + /* See if we are dealing with a quoted phrase. If this is the case, then + ** search for the closing quote and pass the whole string to getNextString() + ** for processing. This is easy to do, as fts3 has no syntax for escaping + ** a quote character embedded in a string. + */ + if( *zInput=='"' ){ + for(ii=1; ii<nInput && zInput[ii]!='"'; ii++); + *pnConsumed = (int)((zInput - z) + ii + 1); + if( ii==nInput ){ + return SQLITE_ERROR; + } + return getNextString(pParse, &zInput[1], ii-1, ppExpr); + } + + if( sqlite3_fts3_enable_parentheses ){ + if( *zInput=='(' ){ + int nConsumed = 0; + pParse->nNest++; +#if !defined(SQLITE_MAX_EXPR_DEPTH) + if( pParse->nNest>1000 ) return SQLITE_ERROR; +#elif SQLITE_MAX_EXPR_DEPTH>0 + if( pParse->nNest>SQLITE_MAX_EXPR_DEPTH ) return SQLITE_ERROR; +#endif + rc = fts3ExprParse(pParse, zInput+1, nInput-1, ppExpr, &nConsumed); + *pnConsumed = (int)(zInput - z) + 1 + nConsumed; + return rc; + }else if( *zInput==')' ){ + pParse->nNest--; + *pnConsumed = (int)((zInput - z) + 1); + *ppExpr = 0; + return SQLITE_DONE; + } + } + + /* If control flows to this point, this must be a regular token, or + ** the end of the input. Read a regular token using the sqlite3_tokenizer + ** interface. Before doing so, figure out if there is an explicit + ** column specifier for the token. + ** + ** TODO: Strangely, it is not possible to associate a column specifier + ** with a quoted phrase, only with a single token. Not sure if this was + ** an implementation artifact or an intentional decision when fts3 was + ** first implemented. Whichever it was, this module duplicates the + ** limitation. + */ + iCol = pParse->iDefaultCol; + iColLen = 0; + for(ii=0; ii<pParse->nCol; ii++){ + const char *zStr = pParse->azCol[ii]; + int nStr = (int)strlen(zStr); + if( nInput>nStr && zInput[nStr]==':' + && sqlite3_strnicmp(zStr, zInput, nStr)==0 + ){ + iCol = ii; + iColLen = (int)((zInput - z) + nStr + 1); + break; + } + } + rc = getNextToken(pParse, iCol, &z[iColLen], n-iColLen, ppExpr, pnConsumed); + *pnConsumed += iColLen; + return rc; +} + +/* +** The argument is an Fts3Expr structure for a binary operator (any type +** except an FTSQUERY_PHRASE). Return an integer value representing the +** precedence of the operator. Lower values have a higher precedence (i.e. +** group more tightly). For example, in the C language, the == operator +** groups more tightly than ||, and would therefore have a higher precedence. +** +** When using the new fts3 query syntax (when SQLITE_ENABLE_FTS3_PARENTHESIS +** is defined), the order of the operators in precedence from highest to +** lowest is: +** +** NEAR +** NOT +** AND (including implicit ANDs) +** OR +** +** Note that when using the old query syntax, the OR operator has a higher +** precedence than the AND operator. +*/ +static int opPrecedence(Fts3Expr *p){ + assert( p->eType!=FTSQUERY_PHRASE ); + if( sqlite3_fts3_enable_parentheses ){ + return p->eType; + }else if( p->eType==FTSQUERY_NEAR ){ + return 1; + }else if( p->eType==FTSQUERY_OR ){ + return 2; + } + assert( p->eType==FTSQUERY_AND ); + return 3; +} + +/* +** Argument ppHead contains a pointer to the current head of a query +** expression tree being parsed. pPrev is the expression node most recently +** inserted into the tree. This function adds pNew, which is always a binary +** operator node, into the expression tree based on the relative precedence +** of pNew and the existing nodes of the tree. This may result in the head +** of the tree changing, in which case *ppHead is set to the new root node. +*/ +static void insertBinaryOperator( + Fts3Expr **ppHead, /* Pointer to the root node of a tree */ + Fts3Expr *pPrev, /* Node most recently inserted into the tree */ + Fts3Expr *pNew /* New binary node to insert into expression tree */ +){ + Fts3Expr *pSplit = pPrev; + while( pSplit->pParent && opPrecedence(pSplit->pParent)<=opPrecedence(pNew) ){ + pSplit = pSplit->pParent; + } + + if( pSplit->pParent ){ + assert( pSplit->pParent->pRight==pSplit ); + pSplit->pParent->pRight = pNew; + pNew->pParent = pSplit->pParent; + }else{ + *ppHead = pNew; + } + pNew->pLeft = pSplit; + pSplit->pParent = pNew; +} + +/* +** Parse the fts3 query expression found in buffer z, length n. This function +** returns either when the end of the buffer is reached or an unmatched +** closing bracket - ')' - is encountered. +** +** If successful, SQLITE_OK is returned, *ppExpr is set to point to the +** parsed form of the expression and *pnConsumed is set to the number of +** bytes read from buffer z. Otherwise, *ppExpr is set to 0 and SQLITE_NOMEM +** (out of memory error) or SQLITE_ERROR (parse error) is returned. +*/ +static int fts3ExprParse( + ParseContext *pParse, /* fts3 query parse context */ + const char *z, int n, /* Text of MATCH query */ + Fts3Expr **ppExpr, /* OUT: Parsed query structure */ + int *pnConsumed /* OUT: Number of bytes consumed */ +){ + Fts3Expr *pRet = 0; + Fts3Expr *pPrev = 0; + Fts3Expr *pNotBranch = 0; /* Only used in legacy parse mode */ + int nIn = n; + const char *zIn = z; + int rc = SQLITE_OK; + int isRequirePhrase = 1; + + while( rc==SQLITE_OK ){ + Fts3Expr *p = 0; + int nByte = 0; + + rc = getNextNode(pParse, zIn, nIn, &p, &nByte); + assert( nByte>0 || (rc!=SQLITE_OK && p==0) ); + if( rc==SQLITE_OK ){ + if( p ){ + int isPhrase; + + if( !sqlite3_fts3_enable_parentheses + && p->eType==FTSQUERY_PHRASE && pParse->isNot + ){ + /* Create an implicit NOT operator. */ + Fts3Expr *pNot = sqlite3Fts3MallocZero(sizeof(Fts3Expr)); + if( !pNot ){ + sqlite3Fts3ExprFree(p); + rc = SQLITE_NOMEM; + goto exprparse_out; + } + pNot->eType = FTSQUERY_NOT; + pNot->pRight = p; + p->pParent = pNot; + if( pNotBranch ){ + pNot->pLeft = pNotBranch; + pNotBranch->pParent = pNot; + } + pNotBranch = pNot; + p = pPrev; + }else{ + int eType = p->eType; + isPhrase = (eType==FTSQUERY_PHRASE || p->pLeft); + + /* The isRequirePhrase variable is set to true if a phrase or + ** an expression contained in parenthesis is required. If a + ** binary operator (AND, OR, NOT or NEAR) is encounted when + ** isRequirePhrase is set, this is a syntax error. + */ + if( !isPhrase && isRequirePhrase ){ + sqlite3Fts3ExprFree(p); + rc = SQLITE_ERROR; + goto exprparse_out; + } + + if( isPhrase && !isRequirePhrase ){ + /* Insert an implicit AND operator. */ + Fts3Expr *pAnd; + assert( pRet && pPrev ); + pAnd = sqlite3Fts3MallocZero(sizeof(Fts3Expr)); + if( !pAnd ){ + sqlite3Fts3ExprFree(p); + rc = SQLITE_NOMEM; + goto exprparse_out; + } + pAnd->eType = FTSQUERY_AND; + insertBinaryOperator(&pRet, pPrev, pAnd); + pPrev = pAnd; + } + + /* This test catches attempts to make either operand of a NEAR + ** operator something other than a phrase. For example, either of + ** the following: + ** + ** (bracketed expression) NEAR phrase + ** phrase NEAR (bracketed expression) + ** + ** Return an error in either case. + */ + if( pPrev && ( + (eType==FTSQUERY_NEAR && !isPhrase && pPrev->eType!=FTSQUERY_PHRASE) + || (eType!=FTSQUERY_PHRASE && isPhrase && pPrev->eType==FTSQUERY_NEAR) + )){ + sqlite3Fts3ExprFree(p); + rc = SQLITE_ERROR; + goto exprparse_out; + } + + if( isPhrase ){ + if( pRet ){ + assert( pPrev && pPrev->pLeft && pPrev->pRight==0 ); + pPrev->pRight = p; + p->pParent = pPrev; + }else{ + pRet = p; + } + }else{ + insertBinaryOperator(&pRet, pPrev, p); + } + isRequirePhrase = !isPhrase; + } + pPrev = p; + } + assert( nByte>0 ); + } + assert( rc!=SQLITE_OK || (nByte>0 && nByte<=nIn) ); + nIn -= nByte; + zIn += nByte; + } + + if( rc==SQLITE_DONE && pRet && isRequirePhrase ){ + rc = SQLITE_ERROR; + } + + if( rc==SQLITE_DONE ){ + rc = SQLITE_OK; + if( !sqlite3_fts3_enable_parentheses && pNotBranch ){ + if( !pRet ){ + rc = SQLITE_ERROR; + }else{ + Fts3Expr *pIter = pNotBranch; + while( pIter->pLeft ){ + pIter = pIter->pLeft; + } + pIter->pLeft = pRet; + pRet->pParent = pIter; + pRet = pNotBranch; + } + } + } + *pnConsumed = n - nIn; + +exprparse_out: + if( rc!=SQLITE_OK ){ + sqlite3Fts3ExprFree(pRet); + sqlite3Fts3ExprFree(pNotBranch); + pRet = 0; + } + *ppExpr = pRet; + return rc; +} + +/* +** Return SQLITE_ERROR if the maximum depth of the expression tree passed +** as the only argument is more than nMaxDepth. +*/ +static int fts3ExprCheckDepth(Fts3Expr *p, int nMaxDepth){ + int rc = SQLITE_OK; + if( p ){ + if( nMaxDepth<0 ){ + rc = SQLITE_TOOBIG; + }else{ + rc = fts3ExprCheckDepth(p->pLeft, nMaxDepth-1); + if( rc==SQLITE_OK ){ + rc = fts3ExprCheckDepth(p->pRight, nMaxDepth-1); + } + } + } + return rc; +} + +/* +** This function attempts to transform the expression tree at (*pp) to +** an equivalent but more balanced form. The tree is modified in place. +** If successful, SQLITE_OK is returned and (*pp) set to point to the +** new root expression node. +** +** nMaxDepth is the maximum allowable depth of the balanced sub-tree. +** +** Otherwise, if an error occurs, an SQLite error code is returned and +** expression (*pp) freed. +*/ +static int fts3ExprBalance(Fts3Expr **pp, int nMaxDepth){ + int rc = SQLITE_OK; /* Return code */ + Fts3Expr *pRoot = *pp; /* Initial root node */ + Fts3Expr *pFree = 0; /* List of free nodes. Linked by pParent. */ + int eType = pRoot->eType; /* Type of node in this tree */ + + if( nMaxDepth==0 ){ + rc = SQLITE_ERROR; + } + + if( rc==SQLITE_OK ){ + if( (eType==FTSQUERY_AND || eType==FTSQUERY_OR) ){ + Fts3Expr **apLeaf; + apLeaf = (Fts3Expr **)sqlite3_malloc64(sizeof(Fts3Expr *) * nMaxDepth); + if( 0==apLeaf ){ + rc = SQLITE_NOMEM; + }else{ + memset(apLeaf, 0, sizeof(Fts3Expr *) * nMaxDepth); + } + + if( rc==SQLITE_OK ){ + int i; + Fts3Expr *p; + + /* Set $p to point to the left-most leaf in the tree of eType nodes. */ + for(p=pRoot; p->eType==eType; p=p->pLeft){ + assert( p->pParent==0 || p->pParent->pLeft==p ); + assert( p->pLeft && p->pRight ); + } + + /* This loop runs once for each leaf in the tree of eType nodes. */ + while( 1 ){ + int iLvl; + Fts3Expr *pParent = p->pParent; /* Current parent of p */ + + assert( pParent==0 || pParent->pLeft==p ); + p->pParent = 0; + if( pParent ){ + pParent->pLeft = 0; + }else{ + pRoot = 0; + } + rc = fts3ExprBalance(&p, nMaxDepth-1); + if( rc!=SQLITE_OK ) break; + + for(iLvl=0; p && iLvl<nMaxDepth; iLvl++){ + if( apLeaf[iLvl]==0 ){ + apLeaf[iLvl] = p; + p = 0; + }else{ + assert( pFree ); + pFree->pLeft = apLeaf[iLvl]; + pFree->pRight = p; + pFree->pLeft->pParent = pFree; + pFree->pRight->pParent = pFree; + + p = pFree; + pFree = pFree->pParent; + p->pParent = 0; + apLeaf[iLvl] = 0; + } + } + if( p ){ + sqlite3Fts3ExprFree(p); + rc = SQLITE_TOOBIG; + break; + } + + /* If that was the last leaf node, break out of the loop */ + if( pParent==0 ) break; + + /* Set $p to point to the next leaf in the tree of eType nodes */ + for(p=pParent->pRight; p->eType==eType; p=p->pLeft); + + /* Remove pParent from the original tree. */ + assert( pParent->pParent==0 || pParent->pParent->pLeft==pParent ); + pParent->pRight->pParent = pParent->pParent; + if( pParent->pParent ){ + pParent->pParent->pLeft = pParent->pRight; + }else{ + assert( pParent==pRoot ); + pRoot = pParent->pRight; + } + + /* Link pParent into the free node list. It will be used as an + ** internal node of the new tree. */ + pParent->pParent = pFree; + pFree = pParent; + } + + if( rc==SQLITE_OK ){ + p = 0; + for(i=0; i<nMaxDepth; i++){ + if( apLeaf[i] ){ + if( p==0 ){ + p = apLeaf[i]; + p->pParent = 0; + }else{ + assert( pFree!=0 ); + pFree->pRight = p; + pFree->pLeft = apLeaf[i]; + pFree->pLeft->pParent = pFree; + pFree->pRight->pParent = pFree; + + p = pFree; + pFree = pFree->pParent; + p->pParent = 0; + } + } + } + pRoot = p; + }else{ + /* An error occurred. Delete the contents of the apLeaf[] array + ** and pFree list. Everything else is cleaned up by the call to + ** sqlite3Fts3ExprFree(pRoot) below. */ + Fts3Expr *pDel; + for(i=0; i<nMaxDepth; i++){ + sqlite3Fts3ExprFree(apLeaf[i]); + } + while( (pDel=pFree)!=0 ){ + pFree = pDel->pParent; + sqlite3_free(pDel); + } + } + + assert( pFree==0 ); + sqlite3_free( apLeaf ); + } + }else if( eType==FTSQUERY_NOT ){ + Fts3Expr *pLeft = pRoot->pLeft; + Fts3Expr *pRight = pRoot->pRight; + + pRoot->pLeft = 0; + pRoot->pRight = 0; + pLeft->pParent = 0; + pRight->pParent = 0; + + rc = fts3ExprBalance(&pLeft, nMaxDepth-1); + if( rc==SQLITE_OK ){ + rc = fts3ExprBalance(&pRight, nMaxDepth-1); + } + + if( rc!=SQLITE_OK ){ + sqlite3Fts3ExprFree(pRight); + sqlite3Fts3ExprFree(pLeft); + }else{ + assert( pLeft && pRight ); + pRoot->pLeft = pLeft; + pLeft->pParent = pRoot; + pRoot->pRight = pRight; + pRight->pParent = pRoot; + } + } + } + + if( rc!=SQLITE_OK ){ + sqlite3Fts3ExprFree(pRoot); + pRoot = 0; + } + *pp = pRoot; + return rc; +} + +/* +** This function is similar to sqlite3Fts3ExprParse(), with the following +** differences: +** +** 1. It does not do expression rebalancing. +** 2. It does not check that the expression does not exceed the +** maximum allowable depth. +** 3. Even if it fails, *ppExpr may still be set to point to an +** expression tree. It should be deleted using sqlite3Fts3ExprFree() +** in this case. +*/ +static int fts3ExprParseUnbalanced( + sqlite3_tokenizer *pTokenizer, /* Tokenizer module */ + int iLangid, /* Language id for tokenizer */ + char **azCol, /* Array of column names for fts3 table */ + int bFts4, /* True to allow FTS4-only syntax */ + int nCol, /* Number of entries in azCol[] */ + int iDefaultCol, /* Default column to query */ + const char *z, int n, /* Text of MATCH query */ + Fts3Expr **ppExpr /* OUT: Parsed query structure */ +){ + int nParsed; + int rc; + ParseContext sParse; + + memset(&sParse, 0, sizeof(ParseContext)); + sParse.pTokenizer = pTokenizer; + sParse.iLangid = iLangid; + sParse.azCol = (const char **)azCol; + sParse.nCol = nCol; + sParse.iDefaultCol = iDefaultCol; + sParse.bFts4 = bFts4; + if( z==0 ){ + *ppExpr = 0; + return SQLITE_OK; + } + if( n<0 ){ + n = (int)strlen(z); + } + rc = fts3ExprParse(&sParse, z, n, ppExpr, &nParsed); + assert( rc==SQLITE_OK || *ppExpr==0 ); + + /* Check for mismatched parenthesis */ + if( rc==SQLITE_OK && sParse.nNest ){ + rc = SQLITE_ERROR; + } + + return rc; +} + +/* +** Parameters z and n contain a pointer to and length of a buffer containing +** an fts3 query expression, respectively. This function attempts to parse the +** query expression and create a tree of Fts3Expr structures representing the +** parsed expression. If successful, *ppExpr is set to point to the head +** of the parsed expression tree and SQLITE_OK is returned. If an error +** occurs, either SQLITE_NOMEM (out-of-memory error) or SQLITE_ERROR (parse +** error) is returned and *ppExpr is set to 0. +** +** If parameter n is a negative number, then z is assumed to point to a +** nul-terminated string and the length is determined using strlen(). +** +** The first parameter, pTokenizer, is passed the fts3 tokenizer module to +** use to normalize query tokens while parsing the expression. The azCol[] +** array, which is assumed to contain nCol entries, should contain the names +** of each column in the target fts3 table, in order from left to right. +** Column names must be nul-terminated strings. +** +** The iDefaultCol parameter should be passed the index of the table column +** that appears on the left-hand-side of the MATCH operator (the default +** column to match against for tokens for which a column name is not explicitly +** specified as part of the query string), or -1 if tokens may by default +** match any table column. +*/ +int sqlite3Fts3ExprParse( + sqlite3_tokenizer *pTokenizer, /* Tokenizer module */ + int iLangid, /* Language id for tokenizer */ + char **azCol, /* Array of column names for fts3 table */ + int bFts4, /* True to allow FTS4-only syntax */ + int nCol, /* Number of entries in azCol[] */ + int iDefaultCol, /* Default column to query */ + const char *z, int n, /* Text of MATCH query */ + Fts3Expr **ppExpr, /* OUT: Parsed query structure */ + char **pzErr /* OUT: Error message (sqlite3_malloc) */ +){ + int rc = fts3ExprParseUnbalanced( + pTokenizer, iLangid, azCol, bFts4, nCol, iDefaultCol, z, n, ppExpr + ); + + /* Rebalance the expression. And check that its depth does not exceed + ** SQLITE_FTS3_MAX_EXPR_DEPTH. */ + if( rc==SQLITE_OK && *ppExpr ){ + rc = fts3ExprBalance(ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH); + if( rc==SQLITE_OK ){ + rc = fts3ExprCheckDepth(*ppExpr, SQLITE_FTS3_MAX_EXPR_DEPTH); + } + } + + if( rc!=SQLITE_OK ){ + sqlite3Fts3ExprFree(*ppExpr); + *ppExpr = 0; + if( rc==SQLITE_TOOBIG ){ + sqlite3Fts3ErrMsg(pzErr, + "FTS expression tree is too large (maximum depth %d)", + SQLITE_FTS3_MAX_EXPR_DEPTH + ); + rc = SQLITE_ERROR; + }else if( rc==SQLITE_ERROR ){ + sqlite3Fts3ErrMsg(pzErr, "malformed MATCH expression: [%s]", z); + } + } + + return rc; +} + +/* +** Free a single node of an expression tree. +*/ +static void fts3FreeExprNode(Fts3Expr *p){ + assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 ); + sqlite3Fts3EvalPhraseCleanup(p->pPhrase); + sqlite3_free(p->aMI); + sqlite3_free(p); +} + +/* +** Free a parsed fts3 query expression allocated by sqlite3Fts3ExprParse(). +** +** This function would be simpler if it recursively called itself. But +** that would mean passing a sufficiently large expression to ExprParse() +** could cause a stack overflow. +*/ +void sqlite3Fts3ExprFree(Fts3Expr *pDel){ + Fts3Expr *p; + assert( pDel==0 || pDel->pParent==0 ); + for(p=pDel; p && (p->pLeft||p->pRight); p=(p->pLeft ? p->pLeft : p->pRight)){ + assert( p->pParent==0 || p==p->pParent->pRight || p==p->pParent->pLeft ); + } + while( p ){ + Fts3Expr *pParent = p->pParent; + fts3FreeExprNode(p); + if( pParent && p==pParent->pLeft && pParent->pRight ){ + p = pParent->pRight; + while( p && (p->pLeft || p->pRight) ){ + assert( p==p->pParent->pRight || p==p->pParent->pLeft ); + p = (p->pLeft ? p->pLeft : p->pRight); + } + }else{ + p = pParent; + } + } +} + +/**************************************************************************** +***************************************************************************** +** Everything after this point is just test code. +*/ + +#ifdef SQLITE_TEST + +#include <stdio.h> + +/* +** Return a pointer to a buffer containing a text representation of the +** expression passed as the first argument. The buffer is obtained from +** sqlite3_malloc(). It is the responsibility of the caller to use +** sqlite3_free() to release the memory. If an OOM condition is encountered, +** NULL is returned. +** +** If the second argument is not NULL, then its contents are prepended to +** the returned expression text and then freed using sqlite3_free(). +*/ +static char *exprToString(Fts3Expr *pExpr, char *zBuf){ + if( pExpr==0 ){ + return sqlite3_mprintf(""); + } + switch( pExpr->eType ){ + case FTSQUERY_PHRASE: { + Fts3Phrase *pPhrase = pExpr->pPhrase; + int i; + zBuf = sqlite3_mprintf( + "%zPHRASE %d 0", zBuf, pPhrase->iColumn); + for(i=0; zBuf && i<pPhrase->nToken; i++){ + zBuf = sqlite3_mprintf("%z %.*s%s", zBuf, + pPhrase->aToken[i].n, pPhrase->aToken[i].z, + (pPhrase->aToken[i].isPrefix?"+":"") + ); + } + return zBuf; + } + + case FTSQUERY_NEAR: + zBuf = sqlite3_mprintf("%zNEAR/%d ", zBuf, pExpr->nNear); + break; + case FTSQUERY_NOT: + zBuf = sqlite3_mprintf("%zNOT ", zBuf); + break; + case FTSQUERY_AND: + zBuf = sqlite3_mprintf("%zAND ", zBuf); + break; + case FTSQUERY_OR: + zBuf = sqlite3_mprintf("%zOR ", zBuf); + break; + } + + if( zBuf ) zBuf = sqlite3_mprintf("%z{", zBuf); + if( zBuf ) zBuf = exprToString(pExpr->pLeft, zBuf); + if( zBuf ) zBuf = sqlite3_mprintf("%z} {", zBuf); + + if( zBuf ) zBuf = exprToString(pExpr->pRight, zBuf); + if( zBuf ) zBuf = sqlite3_mprintf("%z}", zBuf); + + return zBuf; +} + +/* +** This is the implementation of a scalar SQL function used to test the +** expression parser. It should be called as follows: +** +** fts3_exprtest(<tokenizer>, <expr>, <column 1>, ...); +** +** The first argument, <tokenizer>, is the name of the fts3 tokenizer used +** to parse the query expression (see README.tokenizers). The second argument +** is the query expression to parse. Each subsequent argument is the name +** of a column of the fts3 table that the query expression may refer to. +** For example: +** +** SELECT fts3_exprtest('simple', 'Bill col2:Bloggs', 'col1', 'col2'); +*/ +static void fts3ExprTestCommon( + int bRebalance, + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + sqlite3_tokenizer *pTokenizer = 0; + int rc; + char **azCol = 0; + const char *zExpr; + int nExpr; + int nCol; + int ii; + Fts3Expr *pExpr; + char *zBuf = 0; + Fts3Hash *pHash = (Fts3Hash*)sqlite3_user_data(context); + const char *zTokenizer = 0; + char *zErr = 0; + + if( argc<3 ){ + sqlite3_result_error(context, + "Usage: fts3_exprtest(tokenizer, expr, col1, ...", -1 + ); + return; + } + + zTokenizer = (const char*)sqlite3_value_text(argv[0]); + rc = sqlite3Fts3InitTokenizer(pHash, zTokenizer, &pTokenizer, &zErr); + if( rc!=SQLITE_OK ){ + if( rc==SQLITE_NOMEM ){ + sqlite3_result_error_nomem(context); + }else{ + sqlite3_result_error(context, zErr, -1); + } + sqlite3_free(zErr); + return; + } + + zExpr = (const char *)sqlite3_value_text(argv[1]); + nExpr = sqlite3_value_bytes(argv[1]); + nCol = argc-2; + azCol = (char **)sqlite3_malloc64(nCol*sizeof(char *)); + if( !azCol ){ + sqlite3_result_error_nomem(context); + goto exprtest_out; + } + for(ii=0; ii<nCol; ii++){ + azCol[ii] = (char *)sqlite3_value_text(argv[ii+2]); + } + + if( bRebalance ){ + char *zDummy = 0; + rc = sqlite3Fts3ExprParse( + pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr, &zDummy + ); + assert( rc==SQLITE_OK || pExpr==0 ); + sqlite3_free(zDummy); + }else{ + rc = fts3ExprParseUnbalanced( + pTokenizer, 0, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr + ); + } + + if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){ + sqlite3Fts3ExprFree(pExpr); + sqlite3_result_error(context, "Error parsing expression", -1); + }else if( rc==SQLITE_NOMEM || !(zBuf = exprToString(pExpr, 0)) ){ + sqlite3_result_error_nomem(context); + }else{ + sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT); + sqlite3_free(zBuf); + } + + sqlite3Fts3ExprFree(pExpr); + +exprtest_out: + if( pTokenizer ){ + rc = pTokenizer->pModule->xDestroy(pTokenizer); + } + sqlite3_free(azCol); +} + +static void fts3ExprTest( + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + fts3ExprTestCommon(0, context, argc, argv); +} +static void fts3ExprTestRebalance( + sqlite3_context *context, + int argc, + sqlite3_value **argv +){ + fts3ExprTestCommon(1, context, argc, argv); +} + +/* +** Register the query expression parser test function fts3_exprtest() +** with database connection db. +*/ +int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash *pHash){ + int rc = sqlite3_create_function( + db, "fts3_exprtest", -1, SQLITE_UTF8, (void*)pHash, fts3ExprTest, 0, 0 + ); + if( rc==SQLITE_OK ){ + rc = sqlite3_create_function(db, "fts3_exprtest_rebalance", + -1, SQLITE_UTF8, (void*)pHash, fts3ExprTestRebalance, 0, 0 + ); + } + return rc; +} + +#endif +#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */ |