1 /*
2 ** 2011 Jan 27
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.
10 **
11 ******************************************************************************
12 **
13 ** This file is not part of the production FTS code. It is only used for
14 ** testing. It contains a virtual table implementation that provides direct
15 ** access to the full-text index of an FTS table.
16 */
17
18 #include "fts3Int.h"
19 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
20 #ifdef SQLITE_TEST
21
22 #include <string.h>
23 #include <assert.h>
24 #include <stdlib.h>
25
26 typedef struct Fts3termTable Fts3termTable;
27 typedef struct Fts3termCursor Fts3termCursor;
28
29 struct Fts3termTable {
30 sqlite3_vtab base; /* Base class used by SQLite core */
31 int iIndex; /* Index for Fts3Table.aIndex[] */
32 Fts3Table *pFts3Tab;
33 };
34
35 struct Fts3termCursor {
36 sqlite3_vtab_cursor base; /* Base class used by SQLite core */
37 Fts3MultiSegReader csr; /* Must be right after "base" */
38 Fts3SegFilter filter;
39
40 int isEof; /* True if cursor is at EOF */
41 char *pNext;
42
43 sqlite3_int64 iRowid; /* Current 'rowid' value */
44 sqlite3_int64 iDocid; /* Current 'docid' value */
45 int iCol; /* Current 'col' value */
46 int iPos; /* Current 'pos' value */
47 };
48
49 /*
50 ** Schema of the terms table.
51 */
52 #define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, docid, col, pos)"
53
54 /*
55 ** This function does all the work for both the xConnect and xCreate methods.
56 ** These tables have no persistent representation of their own, so xConnect
57 ** and xCreate are identical operations.
58 */
fts3termConnectMethod(sqlite3 * db,void * pCtx,int argc,const char * const * argv,sqlite3_vtab ** ppVtab,char ** pzErr)59 static int fts3termConnectMethod(
60 sqlite3 *db, /* Database connection */
61 void *pCtx, /* Non-zero for an fts4prefix table */
62 int argc, /* Number of elements in argv array */
63 const char * const *argv, /* xCreate/xConnect argument array */
64 sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
65 char **pzErr /* OUT: sqlite3_malloc'd error message */
66 ){
67 char const *zDb; /* Name of database (e.g. "main") */
68 char const *zFts3; /* Name of fts3 table */
69 int nDb; /* Result of strlen(zDb) */
70 int nFts3; /* Result of strlen(zFts3) */
71 sqlite3_int64 nByte; /* Bytes of space to allocate here */
72 int rc; /* value returned by declare_vtab() */
73 Fts3termTable *p; /* Virtual table object to return */
74 int iIndex = 0;
75
76 UNUSED_PARAMETER(pCtx);
77 if( argc==5 ){
78 iIndex = atoi(argv[4]);
79 argc--;
80 }
81
82 /* The user should specify a single argument - the name of an fts3 table. */
83 if( argc!=4 ){
84 sqlite3Fts3ErrMsg(pzErr,
85 "wrong number of arguments to fts4term constructor"
86 );
87 return SQLITE_ERROR;
88 }
89
90 zDb = argv[1];
91 nDb = (int)strlen(zDb);
92 zFts3 = argv[3];
93 nFts3 = (int)strlen(zFts3);
94
95 rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
96 if( rc!=SQLITE_OK ) return rc;
97
98 nByte = sizeof(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
99 p = (Fts3termTable *)sqlite3_malloc64(nByte);
100 if( !p ) return SQLITE_NOMEM;
101 memset(p, 0, (size_t)nByte);
102
103 p->pFts3Tab = (Fts3Table *)&p[1];
104 p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
105 p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
106 p->pFts3Tab->db = db;
107 p->pFts3Tab->nIndex = iIndex+1;
108 p->iIndex = iIndex;
109
110 memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
111 memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
112 sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
113
114 *ppVtab = (sqlite3_vtab *)p;
115 return SQLITE_OK;
116 }
117
118 /*
119 ** This function does the work for both the xDisconnect and xDestroy methods.
120 ** These tables have no persistent representation of their own, so xDisconnect
121 ** and xDestroy are identical operations.
122 */
fts3termDisconnectMethod(sqlite3_vtab * pVtab)123 static int fts3termDisconnectMethod(sqlite3_vtab *pVtab){
124 Fts3termTable *p = (Fts3termTable *)pVtab;
125 Fts3Table *pFts3 = p->pFts3Tab;
126 int i;
127
128 /* Free any prepared statements held */
129 for(i=0; i<SizeofArray(pFts3->aStmt); i++){
130 sqlite3_finalize(pFts3->aStmt[i]);
131 }
132 sqlite3_free(pFts3->zSegmentsTbl);
133 sqlite3_free(p);
134 return SQLITE_OK;
135 }
136
137 #define FTS4AUX_EQ_CONSTRAINT 1
138 #define FTS4AUX_GE_CONSTRAINT 2
139 #define FTS4AUX_LE_CONSTRAINT 4
140
141 /*
142 ** xBestIndex - Analyze a WHERE and ORDER BY clause.
143 */
fts3termBestIndexMethod(sqlite3_vtab * pVTab,sqlite3_index_info * pInfo)144 static int fts3termBestIndexMethod(
145 sqlite3_vtab *pVTab,
146 sqlite3_index_info *pInfo
147 ){
148 UNUSED_PARAMETER(pVTab);
149
150 /* This vtab naturally does "ORDER BY term, docid, col, pos". */
151 if( pInfo->nOrderBy ){
152 int i;
153 for(i=0; i<pInfo->nOrderBy; i++){
154 if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break;
155 }
156 if( i==pInfo->nOrderBy ){
157 pInfo->orderByConsumed = 1;
158 }
159 }
160
161 return SQLITE_OK;
162 }
163
164 /*
165 ** xOpen - Open a cursor.
166 */
fts3termOpenMethod(sqlite3_vtab * pVTab,sqlite3_vtab_cursor ** ppCsr)167 static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
168 Fts3termCursor *pCsr; /* Pointer to cursor object to return */
169
170 UNUSED_PARAMETER(pVTab);
171
172 pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor));
173 if( !pCsr ) return SQLITE_NOMEM;
174 memset(pCsr, 0, sizeof(Fts3termCursor));
175
176 *ppCsr = (sqlite3_vtab_cursor *)pCsr;
177 return SQLITE_OK;
178 }
179
180 /*
181 ** xClose - Close a cursor.
182 */
fts3termCloseMethod(sqlite3_vtab_cursor * pCursor)183 static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){
184 Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
185 Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
186
187 sqlite3Fts3SegmentsClose(pFts3);
188 sqlite3Fts3SegReaderFinish(&pCsr->csr);
189 sqlite3_free(pCsr);
190 return SQLITE_OK;
191 }
192
193 /*
194 ** xNext - Advance the cursor to the next row, if any.
195 */
fts3termNextMethod(sqlite3_vtab_cursor * pCursor)196 static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){
197 Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
198 Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
199 int rc;
200 sqlite3_int64 v;
201
202 /* Increment our pretend rowid value. */
203 pCsr->iRowid++;
204
205 /* Advance to the next term in the full-text index. */
206 if( pCsr->csr.aDoclist==0
207 || pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1]
208 ){
209 rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
210 if( rc!=SQLITE_ROW ){
211 pCsr->isEof = 1;
212 return rc;
213 }
214
215 pCsr->iCol = 0;
216 pCsr->iPos = 0;
217 pCsr->iDocid = 0;
218 pCsr->pNext = pCsr->csr.aDoclist;
219
220 /* Read docid */
221 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid);
222 }
223
224 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
225 if( v==0 ){
226 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
227 pCsr->iDocid += v;
228 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
229 pCsr->iCol = 0;
230 pCsr->iPos = 0;
231 }
232
233 if( v==1 ){
234 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
235 pCsr->iCol += (int)v;
236 pCsr->iPos = 0;
237 pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
238 }
239
240 pCsr->iPos += (int)(v - 2);
241
242 return SQLITE_OK;
243 }
244
245 /*
246 ** xFilter - Initialize a cursor to point at the start of its data.
247 */
fts3termFilterMethod(sqlite3_vtab_cursor * pCursor,int idxNum,const char * idxStr,int nVal,sqlite3_value ** apVal)248 static int fts3termFilterMethod(
249 sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
250 int idxNum, /* Strategy index */
251 const char *idxStr, /* Unused */
252 int nVal, /* Number of elements in apVal */
253 sqlite3_value **apVal /* Arguments for the indexing scheme */
254 ){
255 Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
256 Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
257 Fts3Table *pFts3 = p->pFts3Tab;
258 int rc;
259
260 UNUSED_PARAMETER(nVal);
261 UNUSED_PARAMETER(idxNum);
262 UNUSED_PARAMETER(idxStr);
263 UNUSED_PARAMETER(apVal);
264
265 assert( idxStr==0 && idxNum==0 );
266
267 /* In case this cursor is being reused, close and zero it. */
268 testcase(pCsr->filter.zTerm);
269 sqlite3Fts3SegReaderFinish(&pCsr->csr);
270 memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
271
272 pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
273 pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
274
275 rc = sqlite3Fts3SegReaderCursor(pFts3, 0, p->iIndex, FTS3_SEGCURSOR_ALL,
276 pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
277 );
278 if( rc==SQLITE_OK ){
279 rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
280 }
281 if( rc==SQLITE_OK ){
282 rc = fts3termNextMethod(pCursor);
283 }
284 return rc;
285 }
286
287 /*
288 ** xEof - Return true if the cursor is at EOF, or false otherwise.
289 */
fts3termEofMethod(sqlite3_vtab_cursor * pCursor)290 static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){
291 Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
292 return pCsr->isEof;
293 }
294
295 /*
296 ** xColumn - Return a column value.
297 */
fts3termColumnMethod(sqlite3_vtab_cursor * pCursor,sqlite3_context * pCtx,int iCol)298 static int fts3termColumnMethod(
299 sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
300 sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */
301 int iCol /* Index of column to read value from */
302 ){
303 Fts3termCursor *p = (Fts3termCursor *)pCursor;
304
305 assert( iCol>=0 && iCol<=3 );
306 switch( iCol ){
307 case 0:
308 sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
309 break;
310 case 1:
311 sqlite3_result_int64(pCtx, p->iDocid);
312 break;
313 case 2:
314 sqlite3_result_int64(pCtx, p->iCol);
315 break;
316 default:
317 sqlite3_result_int64(pCtx, p->iPos);
318 break;
319 }
320
321 return SQLITE_OK;
322 }
323
324 /*
325 ** xRowid - Return the current rowid for the cursor.
326 */
fts3termRowidMethod(sqlite3_vtab_cursor * pCursor,sqlite_int64 * pRowid)327 static int fts3termRowidMethod(
328 sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
329 sqlite_int64 *pRowid /* OUT: Rowid value */
330 ){
331 Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
332 *pRowid = pCsr->iRowid;
333 return SQLITE_OK;
334 }
335
336 /*
337 ** Register the fts3term module with database connection db. Return SQLITE_OK
338 ** if successful or an error code if sqlite3_create_module() fails.
339 */
sqlite3Fts3InitTerm(sqlite3 * db)340 int sqlite3Fts3InitTerm(sqlite3 *db){
341 static const sqlite3_module fts3term_module = {
342 0, /* iVersion */
343 fts3termConnectMethod, /* xCreate */
344 fts3termConnectMethod, /* xConnect */
345 fts3termBestIndexMethod, /* xBestIndex */
346 fts3termDisconnectMethod, /* xDisconnect */
347 fts3termDisconnectMethod, /* xDestroy */
348 fts3termOpenMethod, /* xOpen */
349 fts3termCloseMethod, /* xClose */
350 fts3termFilterMethod, /* xFilter */
351 fts3termNextMethod, /* xNext */
352 fts3termEofMethod, /* xEof */
353 fts3termColumnMethod, /* xColumn */
354 fts3termRowidMethod, /* xRowid */
355 0, /* xUpdate */
356 0, /* xBegin */
357 0, /* xSync */
358 0, /* xCommit */
359 0, /* xRollback */
360 0, /* xFindFunction */
361 0, /* xRename */
362 0, /* xSavepoint */
363 0, /* xRelease */
364 0, /* xRollbackTo */
365 0 /* xShadowName */
366 };
367 int rc; /* Return code */
368
369 rc = sqlite3_create_module(db, "fts4term", &fts3term_module, 0);
370 return rc;
371 }
372
373 #endif
374 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
375