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authorHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
committerHans-Christoph Steiner <hans@eds.org>2012-03-30 20:42:12 -0400
commit7bb481fda9ecb134804b49c2ce77ca28f7eea583 (patch)
tree31b520b9914d3e2453968abe375f2c102772c3dc /ext/fts3/fts3_expr.c
Imported Upstream version 2.0.3
Diffstat (limited to 'ext/fts3/fts3_expr.c')
-rw-r--r--ext/fts3/fts3_expr.c984
1 files changed, 984 insertions, 0 deletions
diff --git a/ext/fts3/fts3_expr.c b/ext/fts3/fts3_expr.c
new file mode 100644
index 0000000..1c3a790
--- /dev/null
+++ b/ext/fts3/fts3_expr.c
@@ -0,0 +1,984 @@
+/*
+** 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 */
+ 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 behaviour 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.
+*/
+static void *fts3MallocZero(int nByte){
+ void *pRet = sqlite3_malloc(nByte);
+ if( pRet ) memset(pRet, 0, nByte);
+ return pRet;
+}
+
+
+/*
+** 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 nConsumed = 0;
+
+ rc = pModule->xOpen(pTokenizer, z, n, &pCursor);
+ if( rc==SQLITE_OK ){
+ const char *zToken;
+ int nToken, iStart, iEnd, iPosition;
+ int nByte; /* total space to allocate */
+
+ pCursor->pTokenizer = pTokenizer;
+ rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
+
+ if( rc==SQLITE_OK ){
+ nByte = sizeof(Fts3Expr) + sizeof(Fts3Phrase) + nToken;
+ pRet = (Fts3Expr *)fts3MallocZero(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;
+ }
+ }
+
+ }
+ nConsumed = iEnd;
+ }
+
+ pModule->xClose(pCursor);
+ }
+
+ *pnConsumed = nConsumed;
+ *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, int nNew){
+ void *pRet = sqlite3_realloc(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 = pModule->xOpen(pTokenizer, zInput, nInput, &pCursor);
+ if( rc==SQLITE_OK ){
+ int ii;
+ pCursor->pTokenizer = pTokenizer;
+ for(ii=0; rc==SQLITE_OK; ii++){
+ const char *zByte;
+ int nByte, iBegin, iEnd, iPos;
+ 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;
+}
+
+/*
+** 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 *);
+
+/*
+** 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' ){
+ nNear = 0;
+ for(nKey=5; zInput[nKey]>='0' && zInput[nKey]<='9'; nKey++){
+ nNear = nNear * 10 + (zInput[nKey] - '0');
+ }
+ }
+ }
+
+ /* 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 *)fts3MallocZero(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.
+ */
+ }
+ }
+
+ /* Check for an open bracket. */
+ if( sqlite3_fts3_enable_parentheses ){
+ if( *zInput=='(' ){
+ int nConsumed;
+ pParse->nNest++;
+ rc = fts3ExprParse(pParse, &zInput[1], nInput-1, ppExpr, &nConsumed);
+ if( rc==SQLITE_OK && !*ppExpr ){
+ rc = SQLITE_DONE;
+ }
+ *pnConsumed = (int)((zInput - z) + 1 + nConsumed);
+ return rc;
+ }
+
+ /* Check for a close bracket. */
+ if( *zInput==')' ){
+ pParse->nNest--;
+ *pnConsumed = (int)((zInput - z) + 1);
+ return SQLITE_DONE;
+ }
+ }
+
+ /* 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 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);
+ if( rc==SQLITE_OK ){
+ int isPhrase;
+
+ if( !sqlite3_fts3_enable_parentheses
+ && p->eType==FTSQUERY_PHRASE && pParse->isNot
+ ){
+ /* Create an implicit NOT operator. */
+ Fts3Expr *pNot = fts3MallocZero(sizeof(Fts3Expr));
+ if( !pNot ){
+ sqlite3Fts3ExprFree(p);
+ rc = SQLITE_NOMEM;
+ goto exprparse_out;
+ }
+ pNot->eType = FTSQUERY_NOT;
+ pNot->pRight = p;
+ if( pNotBranch ){
+ pNot->pLeft = pNotBranch;
+ }
+ 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 = fts3MallocZero(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;
+ }
+ assert( nByte>0 );
+ }
+ assert( rc!=SQLITE_OK || (nByte>0 && nByte<=nIn) );
+ nIn -= nByte;
+ zIn += nByte;
+ pPrev = p;
+ }
+
+ 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 = pNotBranch;
+ }
+ }
+ }
+ *pnConsumed = n - nIn;
+
+exprparse_out:
+ if( rc!=SQLITE_OK ){
+ sqlite3Fts3ExprFree(pRet);
+ sqlite3Fts3ExprFree(pNotBranch);
+ pRet = 0;
+ }
+ *ppExpr = pRet;
+ 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 */
+ 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;
+ sParse.pTokenizer = pTokenizer;
+ sParse.azCol = (const char **)azCol;
+ sParse.nCol = nCol;
+ sParse.iDefaultCol = iDefaultCol;
+ sParse.nNest = 0;
+ 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);
+
+ /* Check for mismatched parenthesis */
+ if( rc==SQLITE_OK && sParse.nNest ){
+ rc = SQLITE_ERROR;
+ sqlite3Fts3ExprFree(*ppExpr);
+ *ppExpr = 0;
+ }
+
+ return rc;
+}
+
+/*
+** Free a parsed fts3 query expression allocated by sqlite3Fts3ExprParse().
+*/
+void sqlite3Fts3ExprFree(Fts3Expr *p){
+ if( p ){
+ assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 );
+ sqlite3Fts3ExprFree(p->pLeft);
+ sqlite3Fts3ExprFree(p->pRight);
+ sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
+ sqlite3_free(p->aMI);
+ sqlite3_free(p);
+ }
+}
+
+/****************************************************************************
+*****************************************************************************
+** Everything after this point is just test code.
+*/
+
+#ifdef SQLITE_TEST
+
+#include <stdio.h>
+
+/*
+** Function to query the hash-table of tokenizers (see README.tokenizers).
+*/
+static int queryTestTokenizer(
+ sqlite3 *db,
+ const char *zName,
+ const sqlite3_tokenizer_module **pp
+){
+ int rc;
+ sqlite3_stmt *pStmt;
+ const char zSql[] = "SELECT fts3_tokenizer(?)";
+
+ *pp = 0;
+ rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+ if( rc!=SQLITE_OK ){
+ return rc;
+ }
+
+ sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
+ if( SQLITE_ROW==sqlite3_step(pStmt) ){
+ if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
+ memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
+ }
+ }
+
+ return sqlite3_finalize(pStmt);
+}
+
+/*
+** 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){
+ 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 fts3ExprTest(
+ sqlite3_context *context,
+ int argc,
+ sqlite3_value **argv
+){
+ sqlite3_tokenizer_module const *pModule = 0;
+ sqlite3_tokenizer *pTokenizer = 0;
+ int rc;
+ char **azCol = 0;
+ const char *zExpr;
+ int nExpr;
+ int nCol;
+ int ii;
+ Fts3Expr *pExpr;
+ char *zBuf = 0;
+ sqlite3 *db = sqlite3_context_db_handle(context);
+
+ if( argc<3 ){
+ sqlite3_result_error(context,
+ "Usage: fts3_exprtest(tokenizer, expr, col1, ...", -1
+ );
+ return;
+ }
+
+ rc = queryTestTokenizer(db,
+ (const char *)sqlite3_value_text(argv[0]), &pModule);
+ if( rc==SQLITE_NOMEM ){
+ sqlite3_result_error_nomem(context);
+ goto exprtest_out;
+ }else if( !pModule ){
+ sqlite3_result_error(context, "No such tokenizer module", -1);
+ goto exprtest_out;
+ }
+
+ rc = pModule->xCreate(0, 0, &pTokenizer);
+ assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
+ if( rc==SQLITE_NOMEM ){
+ sqlite3_result_error_nomem(context);
+ goto exprtest_out;
+ }
+ pTokenizer->pModule = pModule;
+
+ zExpr = (const char *)sqlite3_value_text(argv[1]);
+ nExpr = sqlite3_value_bytes(argv[1]);
+ nCol = argc-2;
+ azCol = (char **)sqlite3_malloc(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]);
+ }
+
+ rc = sqlite3Fts3ExprParse(
+ pTokenizer, azCol, 0, nCol, nCol, zExpr, nExpr, &pExpr
+ );
+ if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
+ 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( pModule && pTokenizer ){
+ rc = pModule->xDestroy(pTokenizer);
+ }
+ sqlite3_free(azCol);
+}
+
+/*
+** Register the query expression parser test function fts3_exprtest()
+** with database connection db.
+*/
+int sqlite3Fts3ExprInitTestInterface(sqlite3* db){
+ return sqlite3_create_function(
+ db, "fts3_exprtest", -1, SQLITE_UTF8, 0, fts3ExprTest, 0, 0
+ );
+}
+
+#endif
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */