Annotation of embedaddon/sqlite3/ext/fts3/fts3_term.c, revision 1.1.1.1
1.1 misho 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: */
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: int 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: if( argc==5 ){
77: iIndex = atoi(argv[4]);
78: argc--;
79: }
80:
81: /* The user should specify a single argument - the name of an fts3 table. */
82: if( argc!=4 ){
83: *pzErr = sqlite3_mprintf(
84: "wrong number of arguments to fts4term constructor"
85: );
86: return SQLITE_ERROR;
87: }
88:
89: zDb = argv[1];
90: nDb = strlen(zDb);
91: zFts3 = argv[3];
92: nFts3 = strlen(zFts3);
93:
94: rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
95: if( rc!=SQLITE_OK ) return rc;
96:
97: nByte = sizeof(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
98: p = (Fts3termTable *)sqlite3_malloc(nByte);
99: if( !p ) return SQLITE_NOMEM;
100: memset(p, 0, nByte);
101:
102: p->pFts3Tab = (Fts3Table *)&p[1];
103: p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
104: p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
105: p->pFts3Tab->db = db;
106: p->pFts3Tab->nIndex = iIndex+1;
107: p->iIndex = iIndex;
108:
109: memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
110: memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
111: sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
112:
113: *ppVtab = (sqlite3_vtab *)p;
114: return SQLITE_OK;
115: }
116:
117: /*
118: ** This function does the work for both the xDisconnect and xDestroy methods.
119: ** These tables have no persistent representation of their own, so xDisconnect
120: ** and xDestroy are identical operations.
121: */
122: static int fts3termDisconnectMethod(sqlite3_vtab *pVtab){
123: Fts3termTable *p = (Fts3termTable *)pVtab;
124: Fts3Table *pFts3 = p->pFts3Tab;
125: int i;
126:
127: /* Free any prepared statements held */
128: for(i=0; i<SizeofArray(pFts3->aStmt); i++){
129: sqlite3_finalize(pFts3->aStmt[i]);
130: }
131: sqlite3_free(pFts3->zSegmentsTbl);
132: sqlite3_free(p);
133: return SQLITE_OK;
134: }
135:
136: #define FTS4AUX_EQ_CONSTRAINT 1
137: #define FTS4AUX_GE_CONSTRAINT 2
138: #define FTS4AUX_LE_CONSTRAINT 4
139:
140: /*
141: ** xBestIndex - Analyze a WHERE and ORDER BY clause.
142: */
143: static int fts3termBestIndexMethod(
144: sqlite3_vtab *pVTab,
145: sqlite3_index_info *pInfo
146: ){
147: UNUSED_PARAMETER(pVTab);
148:
149: /* This vtab naturally does "ORDER BY term, docid, col, pos". */
150: if( pInfo->nOrderBy ){
151: int i;
152: for(i=0; i<pInfo->nOrderBy; i++){
153: if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break;
154: }
155: if( i==pInfo->nOrderBy ){
156: pInfo->orderByConsumed = 1;
157: }
158: }
159:
160: return SQLITE_OK;
161: }
162:
163: /*
164: ** xOpen - Open a cursor.
165: */
166: static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
167: Fts3termCursor *pCsr; /* Pointer to cursor object to return */
168:
169: UNUSED_PARAMETER(pVTab);
170:
171: pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor));
172: if( !pCsr ) return SQLITE_NOMEM;
173: memset(pCsr, 0, sizeof(Fts3termCursor));
174:
175: *ppCsr = (sqlite3_vtab_cursor *)pCsr;
176: return SQLITE_OK;
177: }
178:
179: /*
180: ** xClose - Close a cursor.
181: */
182: static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){
183: Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
184: Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
185:
186: sqlite3Fts3SegmentsClose(pFts3);
187: sqlite3Fts3SegReaderFinish(&pCsr->csr);
188: sqlite3_free(pCsr);
189: return SQLITE_OK;
190: }
191:
192: /*
193: ** xNext - Advance the cursor to the next row, if any.
194: */
195: static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){
196: Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
197: Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
198: int rc;
199: sqlite3_int64 v;
200:
201: /* Increment our pretend rowid value. */
202: pCsr->iRowid++;
203:
204: /* Advance to the next term in the full-text index. */
205: if( pCsr->csr.aDoclist==0
206: || pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1]
207: ){
208: rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
209: if( rc!=SQLITE_ROW ){
210: pCsr->isEof = 1;
211: return rc;
212: }
213:
214: pCsr->iCol = 0;
215: pCsr->iPos = 0;
216: pCsr->iDocid = 0;
217: pCsr->pNext = pCsr->csr.aDoclist;
218:
219: /* Read docid */
220: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid);
221: }
222:
223: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
224: if( v==0 ){
225: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
226: pCsr->iDocid += v;
227: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
228: pCsr->iCol = 0;
229: pCsr->iPos = 0;
230: }
231:
232: if( v==1 ){
233: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
234: pCsr->iCol += v;
235: pCsr->iPos = 0;
236: pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
237: }
238:
239: pCsr->iPos += (v - 2);
240:
241: return SQLITE_OK;
242: }
243:
244: /*
245: ** xFilter - Initialize a cursor to point at the start of its data.
246: */
247: static int fts3termFilterMethod(
248: sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
249: int idxNum, /* Strategy index */
250: const char *idxStr, /* Unused */
251: int nVal, /* Number of elements in apVal */
252: sqlite3_value **apVal /* Arguments for the indexing scheme */
253: ){
254: Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
255: Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
256: Fts3Table *pFts3 = p->pFts3Tab;
257: int rc;
258:
259: UNUSED_PARAMETER(nVal);
260: UNUSED_PARAMETER(idxNum);
261: UNUSED_PARAMETER(idxStr);
262: UNUSED_PARAMETER(apVal);
263:
264: assert( idxStr==0 && idxNum==0 );
265:
266: /* In case this cursor is being reused, close and zero it. */
267: testcase(pCsr->filter.zTerm);
268: sqlite3Fts3SegReaderFinish(&pCsr->csr);
269: memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
270:
271: pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
272: pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
273:
274: rc = sqlite3Fts3SegReaderCursor(pFts3, p->iIndex, FTS3_SEGCURSOR_ALL,
275: pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
276: );
277: if( rc==SQLITE_OK ){
278: rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
279: }
280: if( rc==SQLITE_OK ){
281: rc = fts3termNextMethod(pCursor);
282: }
283: return rc;
284: }
285:
286: /*
287: ** xEof - Return true if the cursor is at EOF, or false otherwise.
288: */
289: static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){
290: Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
291: return pCsr->isEof;
292: }
293:
294: /*
295: ** xColumn - Return a column value.
296: */
297: static int fts3termColumnMethod(
298: sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
299: sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */
300: int iCol /* Index of column to read value from */
301: ){
302: Fts3termCursor *p = (Fts3termCursor *)pCursor;
303:
304: assert( iCol>=0 && iCol<=3 );
305: switch( iCol ){
306: case 0:
307: sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
308: break;
309: case 1:
310: sqlite3_result_int64(pCtx, p->iDocid);
311: break;
312: case 2:
313: sqlite3_result_int64(pCtx, p->iCol);
314: break;
315: default:
316: sqlite3_result_int64(pCtx, p->iPos);
317: break;
318: }
319:
320: return SQLITE_OK;
321: }
322:
323: /*
324: ** xRowid - Return the current rowid for the cursor.
325: */
326: static int fts3termRowidMethod(
327: sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
328: sqlite_int64 *pRowid /* OUT: Rowid value */
329: ){
330: Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
331: *pRowid = pCsr->iRowid;
332: return SQLITE_OK;
333: }
334:
335: /*
336: ** Register the fts3term module with database connection db. Return SQLITE_OK
337: ** if successful or an error code if sqlite3_create_module() fails.
338: */
339: int sqlite3Fts3InitTerm(sqlite3 *db){
340: static const sqlite3_module fts3term_module = {
341: 0, /* iVersion */
342: fts3termConnectMethod, /* xCreate */
343: fts3termConnectMethod, /* xConnect */
344: fts3termBestIndexMethod, /* xBestIndex */
345: fts3termDisconnectMethod, /* xDisconnect */
346: fts3termDisconnectMethod, /* xDestroy */
347: fts3termOpenMethod, /* xOpen */
348: fts3termCloseMethod, /* xClose */
349: fts3termFilterMethod, /* xFilter */
350: fts3termNextMethod, /* xNext */
351: fts3termEofMethod, /* xEof */
352: fts3termColumnMethod, /* xColumn */
353: fts3termRowidMethod, /* xRowid */
354: 0, /* xUpdate */
355: 0, /* xBegin */
356: 0, /* xSync */
357: 0, /* xCommit */
358: 0, /* xRollback */
359: 0, /* xFindFunction */
360: 0 /* xRename */
361: };
362: int rc; /* Return code */
363:
364: rc = sqlite3_create_module(db, "fts4term", &fts3term_module, 0);
365: return rc;
366: }
367:
368: #endif
369: #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
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