1 | /* |
2 | ** 2020-03-23 |
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 implements virtual-tables for examining the bytecode content |
14 | ** of a prepared statement. |
15 | */ |
16 | #include "sqliteInt.h" |
17 | #if defined(SQLITE_ENABLE_BYTECODE_VTAB) && !defined(SQLITE_OMIT_VIRTUALTABLE) |
18 | #include "vdbeInt.h" |
19 | |
20 | /* An instance of the bytecode() table-valued function. |
21 | */ |
22 | typedef struct bytecodevtab bytecodevtab; |
23 | struct bytecodevtab { |
24 | sqlite3_vtab base; /* Base class - must be first */ |
25 | sqlite3 *db; /* Database connection */ |
26 | int bTablesUsed; /* 2 for tables_used(). 0 for bytecode(). */ |
27 | }; |
28 | |
29 | /* A cursor for scanning through the bytecode |
30 | */ |
31 | typedef struct bytecodevtab_cursor bytecodevtab_cursor; |
32 | struct bytecodevtab_cursor { |
33 | sqlite3_vtab_cursor base; /* Base class - must be first */ |
34 | sqlite3_stmt *pStmt; /* The statement whose bytecode is displayed */ |
35 | int iRowid; /* The rowid of the output table */ |
36 | int iAddr; /* Address */ |
37 | int needFinalize; /* Cursors owns pStmt and must finalize it */ |
38 | int showSubprograms; /* Provide a listing of subprograms */ |
39 | Op *aOp; /* Operand array */ |
40 | char *zP4; /* Rendered P4 value */ |
41 | const char *zType; /* tables_used.type */ |
42 | const char *zSchema; /* tables_used.schema */ |
43 | const char *zName; /* tables_used.name */ |
44 | Mem sub; /* Subprograms */ |
45 | }; |
46 | |
47 | /* |
48 | ** Create a new bytecode() table-valued function. |
49 | */ |
50 | static int bytecodevtabConnect( |
51 | sqlite3 *db, |
52 | void *pAux, |
53 | int argc, const char *const*argv, |
54 | sqlite3_vtab **ppVtab, |
55 | char **pzErr |
56 | ){ |
57 | bytecodevtab *pNew; |
58 | int rc; |
59 | int isTabUsed = pAux!=0; |
60 | const char *azSchema[2] = { |
61 | /* bytecode() schema */ |
62 | "CREATE TABLE x(" |
63 | "addr INT," |
64 | "opcode TEXT," |
65 | "p1 INT," |
66 | "p2 INT," |
67 | "p3 INT," |
68 | "p4 TEXT," |
69 | "p5 INT," |
70 | "comment TEXT," |
71 | "subprog TEXT," |
72 | "stmt HIDDEN" |
73 | ");" , |
74 | |
75 | /* Tables_used() schema */ |
76 | "CREATE TABLE x(" |
77 | "type TEXT," |
78 | "schema TEXT," |
79 | "name TEXT," |
80 | "wr INT," |
81 | "subprog TEXT," |
82 | "stmt HIDDEN" |
83 | ");" |
84 | }; |
85 | |
86 | rc = sqlite3_declare_vtab(db, azSchema[isTabUsed]); |
87 | if( rc==SQLITE_OK ){ |
88 | pNew = sqlite3_malloc( sizeof(*pNew) ); |
89 | *ppVtab = (sqlite3_vtab*)pNew; |
90 | if( pNew==0 ) return SQLITE_NOMEM; |
91 | memset(pNew, 0, sizeof(*pNew)); |
92 | pNew->db = db; |
93 | pNew->bTablesUsed = isTabUsed*2; |
94 | } |
95 | return rc; |
96 | } |
97 | |
98 | /* |
99 | ** This method is the destructor for bytecodevtab objects. |
100 | */ |
101 | static int bytecodevtabDisconnect(sqlite3_vtab *pVtab){ |
102 | bytecodevtab *p = (bytecodevtab*)pVtab; |
103 | sqlite3_free(p); |
104 | return SQLITE_OK; |
105 | } |
106 | |
107 | /* |
108 | ** Constructor for a new bytecodevtab_cursor object. |
109 | */ |
110 | static int bytecodevtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){ |
111 | bytecodevtab *pVTab = (bytecodevtab*)p; |
112 | bytecodevtab_cursor *pCur; |
113 | pCur = sqlite3_malloc( sizeof(*pCur) ); |
114 | if( pCur==0 ) return SQLITE_NOMEM; |
115 | memset(pCur, 0, sizeof(*pCur)); |
116 | sqlite3VdbeMemInit(&pCur->sub, pVTab->db, 1); |
117 | *ppCursor = &pCur->base; |
118 | return SQLITE_OK; |
119 | } |
120 | |
121 | /* |
122 | ** Clear all internal content from a bytecodevtab cursor. |
123 | */ |
124 | static void bytecodevtabCursorClear(bytecodevtab_cursor *pCur){ |
125 | sqlite3_free(pCur->zP4); |
126 | pCur->zP4 = 0; |
127 | sqlite3VdbeMemRelease(&pCur->sub); |
128 | sqlite3VdbeMemSetNull(&pCur->sub); |
129 | if( pCur->needFinalize ){ |
130 | sqlite3_finalize(pCur->pStmt); |
131 | } |
132 | pCur->pStmt = 0; |
133 | pCur->needFinalize = 0; |
134 | pCur->zType = 0; |
135 | pCur->zSchema = 0; |
136 | pCur->zName = 0; |
137 | } |
138 | |
139 | /* |
140 | ** Destructor for a bytecodevtab_cursor. |
141 | */ |
142 | static int bytecodevtabClose(sqlite3_vtab_cursor *cur){ |
143 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur; |
144 | bytecodevtabCursorClear(pCur); |
145 | sqlite3_free(pCur); |
146 | return SQLITE_OK; |
147 | } |
148 | |
149 | |
150 | /* |
151 | ** Advance a bytecodevtab_cursor to its next row of output. |
152 | */ |
153 | static int bytecodevtabNext(sqlite3_vtab_cursor *cur){ |
154 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur; |
155 | bytecodevtab *pTab = (bytecodevtab*)cur->pVtab; |
156 | int rc; |
157 | if( pCur->zP4 ){ |
158 | sqlite3_free(pCur->zP4); |
159 | pCur->zP4 = 0; |
160 | } |
161 | if( pCur->zName ){ |
162 | pCur->zName = 0; |
163 | pCur->zType = 0; |
164 | pCur->zSchema = 0; |
165 | } |
166 | rc = sqlite3VdbeNextOpcode( |
167 | (Vdbe*)pCur->pStmt, |
168 | pCur->showSubprograms ? &pCur->sub : 0, |
169 | pTab->bTablesUsed, |
170 | &pCur->iRowid, |
171 | &pCur->iAddr, |
172 | &pCur->aOp); |
173 | if( rc!=SQLITE_OK ){ |
174 | sqlite3VdbeMemSetNull(&pCur->sub); |
175 | pCur->aOp = 0; |
176 | } |
177 | return SQLITE_OK; |
178 | } |
179 | |
180 | /* |
181 | ** Return TRUE if the cursor has been moved off of the last |
182 | ** row of output. |
183 | */ |
184 | static int bytecodevtabEof(sqlite3_vtab_cursor *cur){ |
185 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur; |
186 | return pCur->aOp==0; |
187 | } |
188 | |
189 | /* |
190 | ** Return values of columns for the row at which the bytecodevtab_cursor |
191 | ** is currently pointing. |
192 | */ |
193 | static int bytecodevtabColumn( |
194 | sqlite3_vtab_cursor *cur, /* The cursor */ |
195 | sqlite3_context *ctx, /* First argument to sqlite3_result_...() */ |
196 | int i /* Which column to return */ |
197 | ){ |
198 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur; |
199 | bytecodevtab *pVTab = (bytecodevtab*)cur->pVtab; |
200 | Op *pOp = pCur->aOp + pCur->iAddr; |
201 | if( pVTab->bTablesUsed ){ |
202 | if( i==4 ){ |
203 | i = 8; |
204 | }else{ |
205 | if( i<=2 && pCur->zType==0 ){ |
206 | Schema *pSchema; |
207 | HashElem *k; |
208 | int iDb = pOp->p3; |
209 | Pgno iRoot = (Pgno)pOp->p2; |
210 | sqlite3 *db = pVTab->db; |
211 | pSchema = db->aDb[iDb].pSchema; |
212 | pCur->zSchema = db->aDb[iDb].zDbSName; |
213 | for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){ |
214 | Table *pTab = (Table*)sqliteHashData(k); |
215 | if( !IsVirtual(pTab) && pTab->tnum==iRoot ){ |
216 | pCur->zName = pTab->zName; |
217 | pCur->zType = "table" ; |
218 | break; |
219 | } |
220 | } |
221 | if( pCur->zName==0 ){ |
222 | for(k=sqliteHashFirst(&pSchema->idxHash); k; k=sqliteHashNext(k)){ |
223 | Index *pIdx = (Index*)sqliteHashData(k); |
224 | if( pIdx->tnum==iRoot ){ |
225 | pCur->zName = pIdx->zName; |
226 | pCur->zType = "index" ; |
227 | } |
228 | } |
229 | } |
230 | } |
231 | i += 10; |
232 | } |
233 | } |
234 | switch( i ){ |
235 | case 0: /* addr */ |
236 | sqlite3_result_int(ctx, pCur->iAddr); |
237 | break; |
238 | case 1: /* opcode */ |
239 | sqlite3_result_text(ctx, (char*)sqlite3OpcodeName(pOp->opcode), |
240 | -1, SQLITE_STATIC); |
241 | break; |
242 | case 2: /* p1 */ |
243 | sqlite3_result_int(ctx, pOp->p1); |
244 | break; |
245 | case 3: /* p2 */ |
246 | sqlite3_result_int(ctx, pOp->p2); |
247 | break; |
248 | case 4: /* p3 */ |
249 | sqlite3_result_int(ctx, pOp->p3); |
250 | break; |
251 | case 5: /* p4 */ |
252 | case 7: /* comment */ |
253 | if( pCur->zP4==0 ){ |
254 | pCur->zP4 = sqlite3VdbeDisplayP4(pVTab->db, pOp); |
255 | } |
256 | if( i==5 ){ |
257 | sqlite3_result_text(ctx, pCur->zP4, -1, SQLITE_STATIC); |
258 | }else{ |
259 | #ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS |
260 | char *zCom = sqlite3VdbeDisplayComment(pVTab->db, pOp, pCur->zP4); |
261 | sqlite3_result_text(ctx, zCom, -1, sqlite3_free); |
262 | #endif |
263 | } |
264 | break; |
265 | case 6: /* p5 */ |
266 | sqlite3_result_int(ctx, pOp->p5); |
267 | break; |
268 | case 8: { /* subprog */ |
269 | Op *aOp = pCur->aOp; |
270 | assert( aOp[0].opcode==OP_Init ); |
271 | assert( aOp[0].p4.z==0 || strncmp(aOp[0].p4.z,"-" "- " ,3)==0 ); |
272 | if( pCur->iRowid==pCur->iAddr+1 ){ |
273 | break; /* Result is NULL for the main program */ |
274 | }else if( aOp[0].p4.z!=0 ){ |
275 | sqlite3_result_text(ctx, aOp[0].p4.z+3, -1, SQLITE_STATIC); |
276 | }else{ |
277 | sqlite3_result_text(ctx, "(FK)" , 4, SQLITE_STATIC); |
278 | } |
279 | break; |
280 | } |
281 | case 10: /* tables_used.type */ |
282 | sqlite3_result_text(ctx, pCur->zType, -1, SQLITE_STATIC); |
283 | break; |
284 | case 11: /* tables_used.schema */ |
285 | sqlite3_result_text(ctx, pCur->zSchema, -1, SQLITE_STATIC); |
286 | break; |
287 | case 12: /* tables_used.name */ |
288 | sqlite3_result_text(ctx, pCur->zName, -1, SQLITE_STATIC); |
289 | break; |
290 | case 13: /* tables_used.wr */ |
291 | sqlite3_result_int(ctx, pOp->opcode==OP_OpenWrite); |
292 | break; |
293 | } |
294 | return SQLITE_OK; |
295 | } |
296 | |
297 | /* |
298 | ** Return the rowid for the current row. In this implementation, the |
299 | ** rowid is the same as the output value. |
300 | */ |
301 | static int bytecodevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){ |
302 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur; |
303 | *pRowid = pCur->iRowid; |
304 | return SQLITE_OK; |
305 | } |
306 | |
307 | /* |
308 | ** Initialize a cursor. |
309 | ** |
310 | ** idxNum==0 means show all subprograms |
311 | ** idxNum==1 means show only the main bytecode and omit subprograms. |
312 | */ |
313 | static int bytecodevtabFilter( |
314 | sqlite3_vtab_cursor *pVtabCursor, |
315 | int idxNum, const char *idxStr, |
316 | int argc, sqlite3_value **argv |
317 | ){ |
318 | bytecodevtab_cursor *pCur = (bytecodevtab_cursor *)pVtabCursor; |
319 | bytecodevtab *pVTab = (bytecodevtab *)pVtabCursor->pVtab; |
320 | int rc = SQLITE_OK; |
321 | |
322 | bytecodevtabCursorClear(pCur); |
323 | pCur->iRowid = 0; |
324 | pCur->iAddr = 0; |
325 | pCur->showSubprograms = idxNum==0; |
326 | assert( argc==1 ); |
327 | if( sqlite3_value_type(argv[0])==SQLITE_TEXT ){ |
328 | const char *zSql = (const char*)sqlite3_value_text(argv[0]); |
329 | if( zSql==0 ){ |
330 | rc = SQLITE_NOMEM; |
331 | }else{ |
332 | rc = sqlite3_prepare_v2(pVTab->db, zSql, -1, &pCur->pStmt, 0); |
333 | pCur->needFinalize = 1; |
334 | } |
335 | }else{ |
336 | pCur->pStmt = (sqlite3_stmt*)sqlite3_value_pointer(argv[0],"stmt-pointer" ); |
337 | } |
338 | if( pCur->pStmt==0 ){ |
339 | pVTab->base.zErrMsg = sqlite3_mprintf( |
340 | "argument to %s() is not a valid SQL statement" , |
341 | pVTab->bTablesUsed ? "tables_used" : "bytecode" |
342 | ); |
343 | rc = SQLITE_ERROR; |
344 | }else{ |
345 | bytecodevtabNext(pVtabCursor); |
346 | } |
347 | return rc; |
348 | } |
349 | |
350 | /* |
351 | ** We must have a single stmt=? constraint that will be passed through |
352 | ** into the xFilter method. If there is no valid stmt=? constraint, |
353 | ** then return an SQLITE_CONSTRAINT error. |
354 | */ |
355 | static int bytecodevtabBestIndex( |
356 | sqlite3_vtab *tab, |
357 | sqlite3_index_info *pIdxInfo |
358 | ){ |
359 | int i; |
360 | int rc = SQLITE_CONSTRAINT; |
361 | struct sqlite3_index_constraint *p; |
362 | bytecodevtab *pVTab = (bytecodevtab*)tab; |
363 | int iBaseCol = pVTab->bTablesUsed ? 4 : 8; |
364 | pIdxInfo->estimatedCost = (double)100; |
365 | pIdxInfo->estimatedRows = 100; |
366 | pIdxInfo->idxNum = 0; |
367 | for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){ |
368 | if( p->usable==0 ) continue; |
369 | if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==iBaseCol+1 ){ |
370 | rc = SQLITE_OK; |
371 | pIdxInfo->aConstraintUsage[i].omit = 1; |
372 | pIdxInfo->aConstraintUsage[i].argvIndex = 1; |
373 | } |
374 | if( p->op==SQLITE_INDEX_CONSTRAINT_ISNULL && p->iColumn==iBaseCol ){ |
375 | pIdxInfo->aConstraintUsage[i].omit = 1; |
376 | pIdxInfo->idxNum = 1; |
377 | } |
378 | } |
379 | return rc; |
380 | } |
381 | |
382 | /* |
383 | ** This following structure defines all the methods for the |
384 | ** virtual table. |
385 | */ |
386 | static sqlite3_module bytecodevtabModule = { |
387 | /* iVersion */ 0, |
388 | /* xCreate */ 0, |
389 | /* xConnect */ bytecodevtabConnect, |
390 | /* xBestIndex */ bytecodevtabBestIndex, |
391 | /* xDisconnect */ bytecodevtabDisconnect, |
392 | /* xDestroy */ 0, |
393 | /* xOpen */ bytecodevtabOpen, |
394 | /* xClose */ bytecodevtabClose, |
395 | /* xFilter */ bytecodevtabFilter, |
396 | /* xNext */ bytecodevtabNext, |
397 | /* xEof */ bytecodevtabEof, |
398 | /* xColumn */ bytecodevtabColumn, |
399 | /* xRowid */ bytecodevtabRowid, |
400 | /* xUpdate */ 0, |
401 | /* xBegin */ 0, |
402 | /* xSync */ 0, |
403 | /* xCommit */ 0, |
404 | /* xRollback */ 0, |
405 | /* xFindMethod */ 0, |
406 | /* xRename */ 0, |
407 | /* xSavepoint */ 0, |
408 | /* xRelease */ 0, |
409 | /* xRollbackTo */ 0, |
410 | /* xShadowName */ 0 |
411 | }; |
412 | |
413 | |
414 | int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){ |
415 | int rc; |
416 | rc = sqlite3_create_module(db, "bytecode" , &bytecodevtabModule, 0); |
417 | if( rc==SQLITE_OK ){ |
418 | rc = sqlite3_create_module(db, "tables_used" , &bytecodevtabModule, &db); |
419 | } |
420 | return rc; |
421 | } |
422 | #elif defined(SQLITE_ENABLE_BYTECODE_VTAB) |
423 | int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){ return SQLITE_OK; } |
424 | #endif /* SQLITE_ENABLE_BYTECODE_VTAB */ |
425 | |