0
0
mirror of https://github.com/tursodatabase/libsql.git synced 2024-12-16 02:08:49 +00:00
libsql/libsql-sqlite3/ext/fts3/fts3_tokenizer.c
2023-10-16 13:58:16 +02:00

521 lines
14 KiB
C

/*
** 2007 June 22
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This is part of an SQLite module implementing full-text search.
** This particular file implements the generic tokenizer interface.
*/
/*
** The code in this file is only compiled if:
**
** * The FTS3 module is being built as an extension
** (in which case SQLITE_CORE is not defined), or
**
** * The FTS3 module is being built into the core of
** SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
*/
#include "fts3Int.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#include <assert.h>
#include <string.h>
/*
** Return true if the two-argument version of fts3_tokenizer()
** has been activated via a prior call to sqlite3_db_config(db,
** SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
*/
static int fts3TokenizerEnabled(sqlite3_context *context){
sqlite3 *db = sqlite3_context_db_handle(context);
int isEnabled = 0;
sqlite3_db_config(db,SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER,-1,&isEnabled);
return isEnabled;
}
/*
** Implementation of the SQL scalar function for accessing the underlying
** hash table. This function may be called as follows:
**
** SELECT <function-name>(<key-name>);
** SELECT <function-name>(<key-name>, <pointer>);
**
** where <function-name> is the name passed as the second argument
** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer').
**
** If the <pointer> argument is specified, it must be a blob value
** containing a pointer to be stored as the hash data corresponding
** to the string <key-name>. If <pointer> is not specified, then
** the string <key-name> must already exist in the has table. Otherwise,
** an error is returned.
**
** Whether or not the <pointer> argument is specified, the value returned
** is a blob containing the pointer stored as the hash data corresponding
** to string <key-name> (after the hash-table is updated, if applicable).
*/
static void fts3TokenizerFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
Fts3Hash *pHash;
void *pPtr = 0;
const unsigned char *zName;
int nName;
assert( argc==1 || argc==2 );
pHash = (Fts3Hash *)sqlite3_user_data(context);
zName = sqlite3_value_text(argv[0]);
nName = sqlite3_value_bytes(argv[0])+1;
if( argc==2 ){
if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[1]) ){
void *pOld;
int n = sqlite3_value_bytes(argv[1]);
if( zName==0 || n!=sizeof(pPtr) ){
sqlite3_result_error(context, "argument type mismatch", -1);
return;
}
pPtr = *(void **)sqlite3_value_blob(argv[1]);
pOld = sqlite3Fts3HashInsert(pHash, (void *)zName, nName, pPtr);
if( pOld==pPtr ){
sqlite3_result_error(context, "out of memory", -1);
}
}else{
sqlite3_result_error(context, "fts3tokenize disabled", -1);
return;
}
}else{
if( zName ){
pPtr = sqlite3Fts3HashFind(pHash, zName, nName);
}
if( !pPtr ){
char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
sqlite3_result_error(context, zErr, -1);
sqlite3_free(zErr);
return;
}
}
if( fts3TokenizerEnabled(context) || sqlite3_value_frombind(argv[0]) ){
sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
}
}
int sqlite3Fts3IsIdChar(char c){
static const char isFtsIdChar[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 1x */
0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 2x */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, /* 3x */
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 4x */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, /* 5x */
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6x */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, /* 7x */
};
return (c&0x80 || isFtsIdChar[(int)(c)]);
}
const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
const char *z1;
const char *z2 = 0;
/* Find the start of the next token. */
z1 = zStr;
while( z2==0 ){
char c = *z1;
switch( c ){
case '\0': return 0; /* No more tokens here */
case '\'':
case '"':
case '`': {
z2 = z1;
while( *++z2 && (*z2!=c || *++z2==c) );
break;
}
case '[':
z2 = &z1[1];
while( *z2 && z2[0]!=']' ) z2++;
if( *z2 ) z2++;
break;
default:
if( sqlite3Fts3IsIdChar(*z1) ){
z2 = &z1[1];
while( sqlite3Fts3IsIdChar(*z2) ) z2++;
}else{
z1++;
}
}
}
*pn = (int)(z2-z1);
return z1;
}
int sqlite3Fts3InitTokenizer(
Fts3Hash *pHash, /* Tokenizer hash table */
const char *zArg, /* Tokenizer name */
sqlite3_tokenizer **ppTok, /* OUT: Tokenizer (if applicable) */
char **pzErr /* OUT: Set to malloced error message */
){
int rc;
char *z = (char *)zArg;
int n = 0;
char *zCopy;
char *zEnd; /* Pointer to nul-term of zCopy */
sqlite3_tokenizer_module *m;
zCopy = sqlite3_mprintf("%s", zArg);
if( !zCopy ) return SQLITE_NOMEM;
zEnd = &zCopy[strlen(zCopy)];
z = (char *)sqlite3Fts3NextToken(zCopy, &n);
if( z==0 ){
assert( n==0 );
z = zCopy;
}
z[n] = '\0';
sqlite3Fts3Dequote(z);
m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash,z,(int)strlen(z)+1);
if( !m ){
sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", z);
rc = SQLITE_ERROR;
}else{
char const **aArg = 0;
int iArg = 0;
z = &z[n+1];
while( z<zEnd && (NULL!=(z = (char *)sqlite3Fts3NextToken(z, &n))) ){
sqlite3_int64 nNew = sizeof(char *)*(iArg+1);
char const **aNew = (const char **)sqlite3_realloc64((void *)aArg, nNew);
if( !aNew ){
sqlite3_free(zCopy);
sqlite3_free((void *)aArg);
return SQLITE_NOMEM;
}
aArg = aNew;
aArg[iArg++] = z;
z[n] = '\0';
sqlite3Fts3Dequote(z);
z = &z[n+1];
}
rc = m->xCreate(iArg, aArg, ppTok);
assert( rc!=SQLITE_OK || *ppTok );
if( rc!=SQLITE_OK ){
sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer");
}else{
(*ppTok)->pModule = m;
}
sqlite3_free((void *)aArg);
}
sqlite3_free(zCopy);
return rc;
}
#ifdef SQLITE_TEST
#if defined(INCLUDE_SQLITE_TCL_H)
# include "sqlite_tcl.h"
#else
# include "tcl.h"
#endif
#include <string.h>
/*
** Implementation of a special SQL scalar function for testing tokenizers
** designed to be used in concert with the Tcl testing framework. This
** function must be called with two or more arguments:
**
** SELECT <function-name>(<key-name>, ..., <input-string>);
**
** where <function-name> is the name passed as the second argument
** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
**
** The return value is a string that may be interpreted as a Tcl
** list. For each token in the <input-string>, three elements are
** added to the returned list. The first is the token position, the
** second is the token text (folded, stemmed, etc.) and the third is the
** substring of <input-string> associated with the token. For example,
** using the built-in "simple" tokenizer:
**
** SELECT fts_tokenizer_test('simple', 'I don't see how');
**
** will return the string:
**
** "{0 i I 1 dont don't 2 see see 3 how how}"
**
*/
static void testFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
Fts3Hash *pHash;
sqlite3_tokenizer_module *p;
sqlite3_tokenizer *pTokenizer = 0;
sqlite3_tokenizer_cursor *pCsr = 0;
const char *zErr = 0;
const char *zName;
int nName;
const char *zInput;
int nInput;
const char *azArg[64];
const char *zToken;
int nToken = 0;
int iStart = 0;
int iEnd = 0;
int iPos = 0;
int i;
Tcl_Obj *pRet;
if( argc<2 ){
sqlite3_result_error(context, "insufficient arguments", -1);
return;
}
nName = sqlite3_value_bytes(argv[0]);
zName = (const char *)sqlite3_value_text(argv[0]);
nInput = sqlite3_value_bytes(argv[argc-1]);
zInput = (const char *)sqlite3_value_text(argv[argc-1]);
pHash = (Fts3Hash *)sqlite3_user_data(context);
p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
if( !p ){
char *zErr2 = sqlite3_mprintf("unknown tokenizer: %s", zName);
sqlite3_result_error(context, zErr2, -1);
sqlite3_free(zErr2);
return;
}
pRet = Tcl_NewObj();
Tcl_IncrRefCount(pRet);
for(i=1; i<argc-1; i++){
azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
}
if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
zErr = "error in xCreate()";
goto finish;
}
pTokenizer->pModule = p;
if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
zErr = "error in xOpen()";
goto finish;
}
while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
zToken = &zInput[iStart];
nToken = iEnd-iStart;
Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
}
if( SQLITE_OK!=p->xClose(pCsr) ){
zErr = "error in xClose()";
goto finish;
}
if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
zErr = "error in xDestroy()";
goto finish;
}
finish:
if( zErr ){
sqlite3_result_error(context, zErr, -1);
}else{
sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
}
Tcl_DecrRefCount(pRet);
}
static
int registerTokenizer(
sqlite3 *db,
char *zName,
const sqlite3_tokenizer_module *p
){
int rc;
sqlite3_stmt *pStmt;
const char zSql[] = "SELECT fts3_tokenizer(?, ?)";
rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
if( rc!=SQLITE_OK ){
return rc;
}
sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
sqlite3_step(pStmt);
return sqlite3_finalize(pStmt);
}
static
int queryTokenizer(
sqlite3 *db,
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
&& sqlite3_column_bytes(pStmt, 0)==sizeof(*pp)
){
memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
}
}
return sqlite3_finalize(pStmt);
}
void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
/*
** Implementation of the scalar function fts3_tokenizer_internal_test().
** This function is used for testing only, it is not included in the
** build unless SQLITE_TEST is defined.
**
** The purpose of this is to test that the fts3_tokenizer() function
** can be used as designed by the C-code in the queryTokenizer and
** registerTokenizer() functions above. These two functions are repeated
** in the README.tokenizer file as an example, so it is important to
** test them.
**
** To run the tests, evaluate the fts3_tokenizer_internal_test() scalar
** function with no arguments. An assert() will fail if a problem is
** detected. i.e.:
**
** SELECT fts3_tokenizer_internal_test();
**
*/
static void intTestFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int rc;
const sqlite3_tokenizer_module *p1;
const sqlite3_tokenizer_module *p2;
sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
UNUSED_PARAMETER(argc);
UNUSED_PARAMETER(argv);
/* Test the query function */
sqlite3Fts3SimpleTokenizerModule(&p1);
rc = queryTokenizer(db, "simple", &p2);
assert( rc==SQLITE_OK );
assert( p1==p2 );
rc = queryTokenizer(db, "nosuchtokenizer", &p2);
assert( rc==SQLITE_ERROR );
assert( p2==0 );
assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
/* Test the storage function */
if( fts3TokenizerEnabled(context) ){
rc = registerTokenizer(db, "nosuchtokenizer", p1);
assert( rc==SQLITE_OK );
rc = queryTokenizer(db, "nosuchtokenizer", &p2);
assert( rc==SQLITE_OK );
assert( p2==p1 );
}
sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
}
#endif
/*
** Set up SQL objects in database db used to access the contents of
** the hash table pointed to by argument pHash. The hash table must
** been initialized to use string keys, and to take a private copy
** of the key when a value is inserted. i.e. by a call similar to:
**
** sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
**
** This function adds a scalar function (see header comment above
** fts3TokenizerFunc() in this file for details) and, if ENABLE_TABLE is
** defined at compilation time, a temporary virtual table (see header
** comment above struct HashTableVtab) to the database schema. Both
** provide read/write access to the contents of *pHash.
**
** The third argument to this function, zName, is used as the name
** of both the scalar and, if created, the virtual table.
*/
int sqlite3Fts3InitHashTable(
sqlite3 *db,
Fts3Hash *pHash,
const char *zName
){
int rc = SQLITE_OK;
void *p = (void *)pHash;
const int any = SQLITE_UTF8|SQLITE_DIRECTONLY;
#ifdef SQLITE_TEST
char *zTest = 0;
char *zTest2 = 0;
void *pdb = (void *)db;
zTest = sqlite3_mprintf("%s_test", zName);
zTest2 = sqlite3_mprintf("%s_internal_test", zName);
if( !zTest || !zTest2 ){
rc = SQLITE_NOMEM;
}
#endif
if( SQLITE_OK==rc ){
rc = sqlite3_create_function(db, zName, 1, any, p, fts3TokenizerFunc, 0, 0);
}
if( SQLITE_OK==rc ){
rc = sqlite3_create_function(db, zName, 2, any, p, fts3TokenizerFunc, 0, 0);
}
#ifdef SQLITE_TEST
if( SQLITE_OK==rc ){
rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
}
if( SQLITE_OK==rc ){
rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
}
#endif
#ifdef SQLITE_TEST
sqlite3_free(zTest);
sqlite3_free(zTest2);
#endif
return rc;
}
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */