372 lines
10 KiB
C
372 lines
10 KiB
C
/*
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** 2007 June 22
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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******************************************************************************
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**
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** This is part of an SQLite module implementing full-text search.
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** This particular file implements the generic tokenizer interface.
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*/
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/*
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** The code in this file is only compiled if:
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**
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** * The FTS2 module is being built as an extension
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** (in which case SQLITE_CORE is not defined), or
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**
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** * The FTS2 module is being built into the core of
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** SQLite (in which case SQLITE_ENABLE_FTS2 is defined).
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*/
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#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2)
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#include "sqlite3.h"
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#include "sqlite3ext.h"
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SQLITE_EXTENSION_INIT3
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#include "fts2_hash.h"
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#include "fts2_tokenizer.h"
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#include <assert.h>
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/*
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** Implementation of the SQL scalar function for accessing the underlying
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** hash table. This function may be called as follows:
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**
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** SELECT <function-name>(<key-name>);
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** SELECT <function-name>(<key-name>, <pointer>);
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**
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** where <function-name> is the name passed as the second argument
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** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer').
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**
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** If the <pointer> argument is specified, it must be a blob value
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** containing a pointer to be stored as the hash data corresponding
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** to the string <key-name>. If <pointer> is not specified, then
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** the string <key-name> must already exist in the has table. Otherwise,
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** an error is returned.
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**
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** Whether or not the <pointer> argument is specified, the value returned
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** is a blob containing the pointer stored as the hash data corresponding
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** to string <key-name> (after the hash-table is updated, if applicable).
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*/
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static void scalarFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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fts2Hash *pHash;
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void *pPtr = 0;
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const unsigned char *zName;
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int nName;
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assert( argc==1 || argc==2 );
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pHash = (fts2Hash *)sqlite3_user_data(context);
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zName = sqlite3_value_text(argv[0]);
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nName = sqlite3_value_bytes(argv[0])+1;
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if( argc==2 ){
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void *pOld;
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int n = sqlite3_value_bytes(argv[1]);
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if( n!=sizeof(pPtr) ){
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sqlite3_result_error(context, "argument type mismatch", -1);
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return;
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}
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pPtr = *(void **)sqlite3_value_blob(argv[1]);
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pOld = sqlite3Fts2HashInsert(pHash, (void *)zName, nName, pPtr);
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if( pOld==pPtr ){
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sqlite3_result_error(context, "out of memory", -1);
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return;
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}
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}else{
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pPtr = sqlite3Fts2HashFind(pHash, zName, nName);
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if( !pPtr ){
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char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
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sqlite3_result_error(context, zErr, -1);
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sqlite3_free(zErr);
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return;
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}
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}
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sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
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}
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#ifdef SQLITE_TEST
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#include <tcl.h>
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#include <string.h>
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/*
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** Implementation of a special SQL scalar function for testing tokenizers
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** designed to be used in concert with the Tcl testing framework. This
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** function must be called with two arguments:
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**
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** SELECT <function-name>(<key-name>, <input-string>);
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** SELECT <function-name>(<key-name>, <pointer>);
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**
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** where <function-name> is the name passed as the second argument
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** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer')
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** concatenated with the string '_test' (e.g. 'fts2_tokenizer_test').
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**
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** The return value is a string that may be interpreted as a Tcl
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** list. For each token in the <input-string>, three elements are
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** added to the returned list. The first is the token position, the
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** second is the token text (folded, stemmed, etc.) and the third is the
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** substring of <input-string> associated with the token. For example,
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** using the built-in "simple" tokenizer:
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**
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** SELECT fts_tokenizer_test('simple', 'I don't see how');
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**
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** will return the string:
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**
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** "{0 i I 1 dont don't 2 see see 3 how how}"
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**
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*/
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static void testFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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fts2Hash *pHash;
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sqlite3_tokenizer_module *p;
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sqlite3_tokenizer *pTokenizer = 0;
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sqlite3_tokenizer_cursor *pCsr = 0;
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const char *zErr = 0;
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const char *zName;
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int nName;
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const char *zInput;
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int nInput;
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const char *zArg = 0;
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const char *zToken;
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int nToken;
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int iStart;
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int iEnd;
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int iPos;
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Tcl_Obj *pRet;
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assert( argc==2 || argc==3 );
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nName = sqlite3_value_bytes(argv[0]);
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zName = (const char *)sqlite3_value_text(argv[0]);
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nInput = sqlite3_value_bytes(argv[argc-1]);
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zInput = (const char *)sqlite3_value_text(argv[argc-1]);
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if( argc==3 ){
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zArg = (const char *)sqlite3_value_text(argv[1]);
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}
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pHash = (fts2Hash *)sqlite3_user_data(context);
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p = (sqlite3_tokenizer_module *)sqlite3Fts2HashFind(pHash, zName, nName+1);
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if( !p ){
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char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
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sqlite3_result_error(context, zErr, -1);
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sqlite3_free(zErr);
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return;
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}
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pRet = Tcl_NewObj();
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Tcl_IncrRefCount(pRet);
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if( SQLITE_OK!=p->xCreate(zArg ? 1 : 0, &zArg, &pTokenizer) ){
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zErr = "error in xCreate()";
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goto finish;
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}
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pTokenizer->pModule = p;
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if( SQLITE_OK!=p->xOpen(pTokenizer, zInput, nInput, &pCsr) ){
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zErr = "error in xOpen()";
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goto finish;
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}
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pCsr->pTokenizer = pTokenizer;
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while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
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Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
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Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
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zToken = &zInput[iStart];
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nToken = iEnd-iStart;
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Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
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}
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if( SQLITE_OK!=p->xClose(pCsr) ){
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zErr = "error in xClose()";
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goto finish;
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}
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if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
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zErr = "error in xDestroy()";
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goto finish;
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}
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finish:
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if( zErr ){
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sqlite3_result_error(context, zErr, -1);
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}else{
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sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
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}
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Tcl_DecrRefCount(pRet);
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}
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static
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int registerTokenizer(
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sqlite3 *db,
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char *zName,
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const sqlite3_tokenizer_module *p
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){
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int rc;
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sqlite3_stmt *pStmt;
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const char zSql[] = "SELECT fts2_tokenizer(?, ?)";
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rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
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if( rc!=SQLITE_OK ){
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return rc;
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}
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sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
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sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
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sqlite3_step(pStmt);
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return sqlite3_finalize(pStmt);
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}
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static
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int queryFts2Tokenizer(
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sqlite3 *db,
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char *zName,
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const sqlite3_tokenizer_module **pp
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){
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int rc;
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sqlite3_stmt *pStmt;
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const char zSql[] = "SELECT fts2_tokenizer(?)";
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*pp = 0;
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rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
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if( rc!=SQLITE_OK ){
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return rc;
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}
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sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
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if( SQLITE_ROW==sqlite3_step(pStmt) ){
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if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
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memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
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}
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}
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return sqlite3_finalize(pStmt);
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}
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void sqlite3Fts2SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
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/*
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** Implementation of the scalar function fts2_tokenizer_internal_test().
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** This function is used for testing only, it is not included in the
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** build unless SQLITE_TEST is defined.
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**
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** The purpose of this is to test that the fts2_tokenizer() function
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** can be used as designed by the C-code in the queryFts2Tokenizer and
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** registerTokenizer() functions above. These two functions are repeated
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** in the README.tokenizer file as an example, so it is important to
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** test them.
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**
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** To run the tests, evaluate the fts2_tokenizer_internal_test() scalar
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** function with no arguments. An assert() will fail if a problem is
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** detected. i.e.:
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**
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** SELECT fts2_tokenizer_internal_test();
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**
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*/
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static void intTestFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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int rc;
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const sqlite3_tokenizer_module *p1;
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const sqlite3_tokenizer_module *p2;
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sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
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/* Test the query function */
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sqlite3Fts2SimpleTokenizerModule(&p1);
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rc = queryFts2Tokenizer(db, "simple", &p2);
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assert( rc==SQLITE_OK );
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assert( p1==p2 );
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rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2);
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assert( rc==SQLITE_ERROR );
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assert( p2==0 );
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assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
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/* Test the storage function */
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rc = registerTokenizer(db, "nosuchtokenizer", p1);
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assert( rc==SQLITE_OK );
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rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2);
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assert( rc==SQLITE_OK );
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assert( p2==p1 );
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sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
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}
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#endif
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/*
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** Set up SQL objects in database db used to access the contents of
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** the hash table pointed to by argument pHash. The hash table must
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** been initialized to use string keys, and to take a private copy
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** of the key when a value is inserted. i.e. by a call similar to:
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**
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** sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1);
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**
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** This function adds a scalar function (see header comment above
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** scalarFunc() in this file for details) and, if ENABLE_TABLE is
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** defined at compilation time, a temporary virtual table (see header
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** comment above struct HashTableVtab) to the database schema. Both
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** provide read/write access to the contents of *pHash.
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**
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** The third argument to this function, zName, is used as the name
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** of both the scalar and, if created, the virtual table.
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*/
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int sqlite3Fts2InitHashTable(
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sqlite3 *db,
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fts2Hash *pHash,
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const char *zName
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){
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int rc = SQLITE_OK;
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void *p = (void *)pHash;
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const int any = SQLITE_ANY;
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char *zTest = 0;
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char *zTest2 = 0;
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#ifdef SQLITE_TEST
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void *pdb = (void *)db;
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zTest = sqlite3_mprintf("%s_test", zName);
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zTest2 = sqlite3_mprintf("%s_internal_test", zName);
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if( !zTest || !zTest2 ){
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rc = SQLITE_NOMEM;
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}
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#endif
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if( rc!=SQLITE_OK
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|| (rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0))
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|| (rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0))
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#ifdef SQLITE_TEST
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|| (rc = sqlite3_create_function(db, zTest, 2, any, p, testFunc, 0, 0))
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|| (rc = sqlite3_create_function(db, zTest, 3, any, p, testFunc, 0, 0))
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|| (rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0))
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#endif
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);
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sqlite3_free(zTest);
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sqlite3_free(zTest2);
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return rc;
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}
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#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */
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