Finish refactoring of DomCodeToUsLayoutKeyboardCode().
[chromium-blink-merge.git] / third_party / sqlite / sqlite-src-3080704 / ext / fts3 / fts3_tokenize_vtab.c
blob364852ef82e2cb419b8b3dc0e06fbd73267990e9
1 /*
2 ** 2013 Apr 22
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
11 ******************************************************************************
13 ** This file contains code for the "fts3tokenize" virtual table module.
14 ** An fts3tokenize virtual table is created as follows:
16 ** CREATE VIRTUAL TABLE <tbl> USING fts3tokenize(
17 ** <tokenizer-name>, <arg-1>, ...
18 ** );
20 ** The table created has the following schema:
22 ** CREATE TABLE <tbl>(input, token, start, end, position)
24 ** When queried, the query must include a WHERE clause of type:
26 ** input = <string>
28 ** The virtual table module tokenizes this <string>, using the FTS3
29 ** tokenizer specified by the arguments to the CREATE VIRTUAL TABLE
30 ** statement and returns one row for each token in the result. With
31 ** fields set as follows:
33 ** input: Always set to a copy of <string>
34 ** token: A token from the input.
35 ** start: Byte offset of the token within the input <string>.
36 ** end: Byte offset of the byte immediately following the end of the
37 ** token within the input string.
38 ** pos: Token offset of token within input.
41 #include "fts3Int.h"
42 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
44 #include <string.h>
45 #include <assert.h>
47 typedef struct Fts3tokTable Fts3tokTable;
48 typedef struct Fts3tokCursor Fts3tokCursor;
51 ** Virtual table structure.
53 struct Fts3tokTable {
54 sqlite3_vtab base; /* Base class used by SQLite core */
55 const sqlite3_tokenizer_module *pMod;
56 sqlite3_tokenizer *pTok;
60 ** Virtual table cursor structure.
62 struct Fts3tokCursor {
63 sqlite3_vtab_cursor base; /* Base class used by SQLite core */
64 char *zInput; /* Input string */
65 sqlite3_tokenizer_cursor *pCsr; /* Cursor to iterate through zInput */
66 int iRowid; /* Current 'rowid' value */
67 const char *zToken; /* Current 'token' value */
68 int nToken; /* Size of zToken in bytes */
69 int iStart; /* Current 'start' value */
70 int iEnd; /* Current 'end' value */
71 int iPos; /* Current 'pos' value */
75 ** Query FTS for the tokenizer implementation named zName.
77 static int fts3tokQueryTokenizer(
78 Fts3Hash *pHash,
79 const char *zName,
80 const sqlite3_tokenizer_module **pp,
81 char **pzErr
83 sqlite3_tokenizer_module *p;
84 int nName = (int)strlen(zName);
86 p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
87 if( !p ){
88 *pzErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
89 return SQLITE_ERROR;
92 *pp = p;
93 return SQLITE_OK;
97 ** The second argument, argv[], is an array of pointers to nul-terminated
98 ** strings. This function makes a copy of the array and strings into a
99 ** single block of memory. It then dequotes any of the strings that appear
100 ** to be quoted.
102 ** If successful, output parameter *pazDequote is set to point at the
103 ** array of dequoted strings and SQLITE_OK is returned. The caller is
104 ** responsible for eventually calling sqlite3_free() to free the array
105 ** in this case. Or, if an error occurs, an SQLite error code is returned.
106 ** The final value of *pazDequote is undefined in this case.
108 static int fts3tokDequoteArray(
109 int argc, /* Number of elements in argv[] */
110 const char * const *argv, /* Input array */
111 char ***pazDequote /* Output array */
113 int rc = SQLITE_OK; /* Return code */
114 if( argc==0 ){
115 *pazDequote = 0;
116 }else{
117 int i;
118 int nByte = 0;
119 char **azDequote;
121 for(i=0; i<argc; i++){
122 nByte += (int)(strlen(argv[i]) + 1);
125 *pazDequote = azDequote = sqlite3_malloc(sizeof(char *)*argc + nByte);
126 if( azDequote==0 ){
127 rc = SQLITE_NOMEM;
128 }else{
129 char *pSpace = (char *)&azDequote[argc];
130 for(i=0; i<argc; i++){
131 int n = (int)strlen(argv[i]);
132 azDequote[i] = pSpace;
133 memcpy(pSpace, argv[i], n+1);
134 sqlite3Fts3Dequote(pSpace);
135 pSpace += (n+1);
140 return rc;
144 ** Schema of the tokenizer table.
146 #define FTS3_TOK_SCHEMA "CREATE TABLE x(input, token, start, end, position)"
149 ** This function does all the work for both the xConnect and xCreate methods.
150 ** These tables have no persistent representation of their own, so xConnect
151 ** and xCreate are identical operations.
153 ** argv[0]: module name
154 ** argv[1]: database name
155 ** argv[2]: table name
156 ** argv[3]: first argument (tokenizer name)
158 static int fts3tokConnectMethod(
159 sqlite3 *db, /* Database connection */
160 void *pHash, /* Hash table of tokenizers */
161 int argc, /* Number of elements in argv array */
162 const char * const *argv, /* xCreate/xConnect argument array */
163 sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
164 char **pzErr /* OUT: sqlite3_malloc'd error message */
166 Fts3tokTable *pTab;
167 const sqlite3_tokenizer_module *pMod = 0;
168 sqlite3_tokenizer *pTok = 0;
169 int rc;
170 char **azDequote = 0;
171 int nDequote;
173 rc = sqlite3_declare_vtab(db, FTS3_TOK_SCHEMA);
174 if( rc!=SQLITE_OK ) return rc;
176 nDequote = argc-3;
177 rc = fts3tokDequoteArray(nDequote, &argv[3], &azDequote);
179 if( rc==SQLITE_OK ){
180 const char *zModule;
181 if( nDequote<1 ){
182 zModule = "simple";
183 }else{
184 zModule = azDequote[0];
186 rc = fts3tokQueryTokenizer((Fts3Hash*)pHash, zModule, &pMod, pzErr);
189 assert( (rc==SQLITE_OK)==(pMod!=0) );
190 if( rc==SQLITE_OK ){
191 const char * const *azArg = (const char * const *)&azDequote[1];
192 rc = pMod->xCreate((nDequote>1 ? nDequote-1 : 0), azArg, &pTok);
195 if( rc==SQLITE_OK ){
196 pTab = (Fts3tokTable *)sqlite3_malloc(sizeof(Fts3tokTable));
197 if( pTab==0 ){
198 rc = SQLITE_NOMEM;
202 if( rc==SQLITE_OK ){
203 memset(pTab, 0, sizeof(Fts3tokTable));
204 pTab->pMod = pMod;
205 pTab->pTok = pTok;
206 *ppVtab = &pTab->base;
207 }else{
208 if( pTok ){
209 pMod->xDestroy(pTok);
213 sqlite3_free(azDequote);
214 return rc;
218 ** This function does the work for both the xDisconnect and xDestroy methods.
219 ** These tables have no persistent representation of their own, so xDisconnect
220 ** and xDestroy are identical operations.
222 static int fts3tokDisconnectMethod(sqlite3_vtab *pVtab){
223 Fts3tokTable *pTab = (Fts3tokTable *)pVtab;
225 pTab->pMod->xDestroy(pTab->pTok);
226 sqlite3_free(pTab);
227 return SQLITE_OK;
231 ** xBestIndex - Analyze a WHERE and ORDER BY clause.
233 static int fts3tokBestIndexMethod(
234 sqlite3_vtab *pVTab,
235 sqlite3_index_info *pInfo
237 int i;
238 UNUSED_PARAMETER(pVTab);
240 for(i=0; i<pInfo->nConstraint; i++){
241 if( pInfo->aConstraint[i].usable
242 && pInfo->aConstraint[i].iColumn==0
243 && pInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ
245 pInfo->idxNum = 1;
246 pInfo->aConstraintUsage[i].argvIndex = 1;
247 pInfo->aConstraintUsage[i].omit = 1;
248 pInfo->estimatedCost = 1;
249 return SQLITE_OK;
253 pInfo->idxNum = 0;
254 assert( pInfo->estimatedCost>1000000.0 );
256 return SQLITE_OK;
260 ** xOpen - Open a cursor.
262 static int fts3tokOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
263 Fts3tokCursor *pCsr;
264 UNUSED_PARAMETER(pVTab);
266 pCsr = (Fts3tokCursor *)sqlite3_malloc(sizeof(Fts3tokCursor));
267 if( pCsr==0 ){
268 return SQLITE_NOMEM;
270 memset(pCsr, 0, sizeof(Fts3tokCursor));
272 *ppCsr = (sqlite3_vtab_cursor *)pCsr;
273 return SQLITE_OK;
277 ** Reset the tokenizer cursor passed as the only argument. As if it had
278 ** just been returned by fts3tokOpenMethod().
280 static void fts3tokResetCursor(Fts3tokCursor *pCsr){
281 if( pCsr->pCsr ){
282 Fts3tokTable *pTab = (Fts3tokTable *)(pCsr->base.pVtab);
283 pTab->pMod->xClose(pCsr->pCsr);
284 pCsr->pCsr = 0;
286 sqlite3_free(pCsr->zInput);
287 pCsr->zInput = 0;
288 pCsr->zToken = 0;
289 pCsr->nToken = 0;
290 pCsr->iStart = 0;
291 pCsr->iEnd = 0;
292 pCsr->iPos = 0;
293 pCsr->iRowid = 0;
297 ** xClose - Close a cursor.
299 static int fts3tokCloseMethod(sqlite3_vtab_cursor *pCursor){
300 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
302 fts3tokResetCursor(pCsr);
303 sqlite3_free(pCsr);
304 return SQLITE_OK;
308 ** xNext - Advance the cursor to the next row, if any.
310 static int fts3tokNextMethod(sqlite3_vtab_cursor *pCursor){
311 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
312 Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
313 int rc; /* Return code */
315 pCsr->iRowid++;
316 rc = pTab->pMod->xNext(pCsr->pCsr,
317 &pCsr->zToken, &pCsr->nToken,
318 &pCsr->iStart, &pCsr->iEnd, &pCsr->iPos
321 if( rc!=SQLITE_OK ){
322 fts3tokResetCursor(pCsr);
323 if( rc==SQLITE_DONE ) rc = SQLITE_OK;
326 return rc;
330 ** xFilter - Initialize a cursor to point at the start of its data.
332 static int fts3tokFilterMethod(
333 sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
334 int idxNum, /* Strategy index */
335 const char *idxStr, /* Unused */
336 int nVal, /* Number of elements in apVal */
337 sqlite3_value **apVal /* Arguments for the indexing scheme */
339 int rc = SQLITE_ERROR;
340 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
341 Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
342 UNUSED_PARAMETER(idxStr);
343 UNUSED_PARAMETER(nVal);
345 fts3tokResetCursor(pCsr);
346 if( idxNum==1 ){
347 const char *zByte = (const char *)sqlite3_value_text(apVal[0]);
348 int nByte = sqlite3_value_bytes(apVal[0]);
349 pCsr->zInput = sqlite3_malloc(nByte+1);
350 if( pCsr->zInput==0 ){
351 rc = SQLITE_NOMEM;
352 }else{
353 memcpy(pCsr->zInput, zByte, nByte);
354 pCsr->zInput[nByte] = 0;
355 rc = pTab->pMod->xOpen(pTab->pTok, pCsr->zInput, nByte, &pCsr->pCsr);
356 if( rc==SQLITE_OK ){
357 pCsr->pCsr->pTokenizer = pTab->pTok;
362 if( rc!=SQLITE_OK ) return rc;
363 return fts3tokNextMethod(pCursor);
367 ** xEof - Return true if the cursor is at EOF, or false otherwise.
369 static int fts3tokEofMethod(sqlite3_vtab_cursor *pCursor){
370 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
371 return (pCsr->zToken==0);
375 ** xColumn - Return a column value.
377 static int fts3tokColumnMethod(
378 sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
379 sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */
380 int iCol /* Index of column to read value from */
382 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
384 /* CREATE TABLE x(input, token, start, end, position) */
385 switch( iCol ){
386 case 0:
387 sqlite3_result_text(pCtx, pCsr->zInput, -1, SQLITE_TRANSIENT);
388 break;
389 case 1:
390 sqlite3_result_text(pCtx, pCsr->zToken, pCsr->nToken, SQLITE_TRANSIENT);
391 break;
392 case 2:
393 sqlite3_result_int(pCtx, pCsr->iStart);
394 break;
395 case 3:
396 sqlite3_result_int(pCtx, pCsr->iEnd);
397 break;
398 default:
399 assert( iCol==4 );
400 sqlite3_result_int(pCtx, pCsr->iPos);
401 break;
403 return SQLITE_OK;
407 ** xRowid - Return the current rowid for the cursor.
409 static int fts3tokRowidMethod(
410 sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
411 sqlite_int64 *pRowid /* OUT: Rowid value */
413 Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
414 *pRowid = (sqlite3_int64)pCsr->iRowid;
415 return SQLITE_OK;
419 ** Register the fts3tok module with database connection db. Return SQLITE_OK
420 ** if successful or an error code if sqlite3_create_module() fails.
422 int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash){
423 static const sqlite3_module fts3tok_module = {
424 0, /* iVersion */
425 fts3tokConnectMethod, /* xCreate */
426 fts3tokConnectMethod, /* xConnect */
427 fts3tokBestIndexMethod, /* xBestIndex */
428 fts3tokDisconnectMethod, /* xDisconnect */
429 fts3tokDisconnectMethod, /* xDestroy */
430 fts3tokOpenMethod, /* xOpen */
431 fts3tokCloseMethod, /* xClose */
432 fts3tokFilterMethod, /* xFilter */
433 fts3tokNextMethod, /* xNext */
434 fts3tokEofMethod, /* xEof */
435 fts3tokColumnMethod, /* xColumn */
436 fts3tokRowidMethod, /* xRowid */
437 0, /* xUpdate */
438 0, /* xBegin */
439 0, /* xSync */
440 0, /* xCommit */
441 0, /* xRollback */
442 0, /* xFindFunction */
443 0, /* xRename */
444 0, /* xSavepoint */
445 0, /* xRelease */
446 0 /* xRollbackTo */
448 int rc; /* Return code */
450 rc = sqlite3_create_module(db, "fts3tokenize", &fts3tok_module, (void*)pHash);
451 return rc;
454 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */