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/*
* Copyright (C) 2011 Nokia <ivan.frade@nokia.com>
*
* Author: Carlos Garnacho <carlos@lanedo.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
/* FTS3/4 Tokenizer using TrackerParser */
#include "config.h"
#include <assert.h>
#include <string.h>
#include <libtracker-common/tracker-parser.h>
#include "tracker-fts-tokenizer.h"
#include "tracker-fts-config.h"
#include "fts3_tokenizer.h"
typedef struct TrackerTokenizer TrackerTokenizer;
typedef struct TrackerCursor TrackerCursor;
struct TrackerTokenizer {
sqlite3_tokenizer base;
TrackerLanguage *language;
int max_word_length;
int max_words;
gboolean enable_stemmer;
gboolean enable_unaccent;
gboolean ignore_numbers;
gboolean ignore_stop_words;
};
struct TrackerCursor {
sqlite3_tokenizer_cursor base;
TrackerTokenizer *tokenizer;
TrackerParser *parser;
guint n_words;
};
/*
** Create a new tokenizer instance.
*/
static int trackerCreate(
int argc, /* Number of entries in argv[] */
const char * const *argv, /* Tokenizer creation arguments */
sqlite3_tokenizer **ppTokenizer /* OUT: Created tokenizer */
){
TrackerTokenizer *p;
TrackerFTSConfig *config;
p = (TrackerTokenizer *)sqlite3_malloc(sizeof(TrackerTokenizer));
if( !p ){
return SQLITE_NOMEM;
}
memset(p, 0, sizeof(TrackerTokenizer));
p->language = tracker_language_new (NULL);
config = tracker_fts_config_new ();
p->max_word_length = tracker_fts_config_get_max_word_length (config);
p->enable_stemmer = tracker_fts_config_get_enable_stemmer (config);
p->enable_unaccent = tracker_fts_config_get_enable_unaccent (config);
p->ignore_numbers = tracker_fts_config_get_ignore_numbers (config);
/* disable stop words if TRACKER_FTS_STOP_WORDS is set to 0 - used by tests
* otherwise, get value from the conf file */
p->ignore_stop_words = (g_strcmp0 (g_getenv ("TRACKER_FTS_STOP_WORDS"), "0") == 0 ?
FALSE : tracker_fts_config_get_ignore_stop_words (config));
p->max_words = tracker_fts_config_get_max_words_to_index (config);
g_object_unref (config);
*ppTokenizer = (sqlite3_tokenizer *)p;
return SQLITE_OK;
}
/*
** Destroy a tokenizer
*/
static int trackerDestroy(sqlite3_tokenizer *pTokenizer){
TrackerTokenizer *p = (TrackerTokenizer *)pTokenizer;
g_object_unref (p->language);
sqlite3_free(p);
return SQLITE_OK;
}
/*
** Prepare to begin tokenizing a particular string. The input
** string to be tokenized is pInput[0..nBytes-1]. A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int trackerOpen(
sqlite3_tokenizer *pTokenizer, /* The tokenizer */
const char *zInput, /* Input string */
int nInput, /* Length of zInput in bytes */
sqlite3_tokenizer_cursor **ppCursor /* OUT: Tokenization cursor */
){
TrackerTokenizer *p = (TrackerTokenizer *)pTokenizer;
TrackerParser *parser;
TrackerCursor *pCsr;
if ( nInput<0 ){
nInput = strlen(zInput);
}
parser = tracker_parser_new (p->language);
tracker_parser_reset (parser, zInput, nInput,
p->max_word_length,
p->enable_stemmer,
p->enable_unaccent,
p->ignore_stop_words,
TRUE,
p->ignore_numbers);
pCsr = (TrackerCursor *)sqlite3_malloc(sizeof(TrackerCursor));
memset(pCsr, 0, sizeof(TrackerCursor));
pCsr->tokenizer = p;
pCsr->parser = parser;
*ppCursor = (sqlite3_tokenizer_cursor *)pCsr;
return SQLITE_OK;
}
/*
** Close a tokenization cursor.
*/
static int trackerClose(sqlite3_tokenizer_cursor *pCursor){
TrackerCursor *pCsr = (TrackerCursor *)pCursor;
tracker_parser_free (pCsr->parser);
sqlite3_free(pCsr);
return SQLITE_OK;
}
/*
** Extract the next token from a tokenization cursor.
*/
static int trackerNext(
sqlite3_tokenizer_cursor *pCursor, /* Cursor returned by simpleOpen */
const char **ppToken, /* OUT: *ppToken is the token text */
int *pnBytes, /* OUT: Number of bytes in token */
int *piStartOffset, /* OUT: Starting offset of token */
int *piEndOffset, /* OUT: Ending offset of token */
int *piPosition /* OUT: Position integer of token */
){
TrackerCursor *cursor = (TrackerCursor *) pCursor;
TrackerTokenizer *p;
const gchar *pToken;
gboolean stop_word;
int pos, start, end, len;
p = cursor->tokenizer;
if (cursor->n_words > p->max_words){
return SQLITE_DONE;
}
do {
pToken = tracker_parser_next (cursor->parser,
&pos,
&start, &end,
&stop_word,
&len);
if (!pToken){
return SQLITE_DONE;
}
} while (stop_word && p->ignore_stop_words);
*ppToken = pToken;
*piStartOffset = start;
*piEndOffset = end;
*piPosition = pos;
*pnBytes = len;
cursor->n_words++;
return SQLITE_OK;
}
/*
** The set of routines that implement the simple tokenizer
*/
static const sqlite3_tokenizer_module trackerTokenizerModule = {
0, /* iVersion */
trackerCreate, /* xCreate */
trackerDestroy, /* xDestroy */
trackerOpen, /* xOpen */
trackerClose, /* xClose */
trackerNext, /* xNext */
};
/*
** Set *ppModule to point at the implementation of the tracker tokenizer.
*/
gboolean tracker_tokenizer_initialize (sqlite3 *db) {
const sqlite3_tokenizer_module *pTokenizer;
int rc = SQLITE_OK;
sqlite3_stmt *stmt;
pTokenizer = &trackerTokenizerModule;
rc = sqlite3_prepare_v2(db, "SELECT fts3_tokenizer(?, ?)",
-1, &stmt, 0);
if (rc != SQLITE_OK) {
return FALSE;
}
sqlite3_bind_text(stmt, 1, "TrackerTokenizer", -1, SQLITE_STATIC);
sqlite3_bind_blob(stmt, 2, &pTokenizer, sizeof(pTokenizer), SQLITE_STATIC);
sqlite3_step(stmt);
rc = sqlite3_finalize(stmt);
return (rc == SQLITE_OK);
}
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