forked from sqlite/sqlite
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathcallback.c
More file actions
485 lines (454 loc) · 15.9 KB
/
callback.c
File metadata and controls
485 lines (454 loc) · 15.9 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
/*
** 2005 May 23
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains functions used to access the internal hash tables
** of user defined functions and collation sequences.
*/
#include "sqliteInt.h"
/*
** Invoke the 'collation needed' callback to request a collation sequence
** in the encoding enc of name zName, length nName.
*/
static void callCollNeeded(sqlite3 *db, int enc, const char *zName){
assert( !db->xCollNeeded || !db->xCollNeeded16 );
if( db->xCollNeeded ){
char *zExternal = sqlite3DbStrDup(db, zName);
if( !zExternal ) return;
db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal);
sqlite3DbFree(db, zExternal);
}
#ifndef SQLITE_OMIT_UTF16
if( db->xCollNeeded16 ){
char const *zExternal;
sqlite3_value *pTmp = sqlite3ValueNew(db);
sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC);
zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE);
if( zExternal ){
db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal);
}
sqlite3ValueFree(pTmp);
}
#endif
}
/*
** This routine is called if the collation factory fails to deliver a
** collation function in the best encoding but there may be other versions
** of this collation function (for other text encodings) available. Use one
** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if
** possible.
*/
static int synthCollSeq(sqlite3 *db, CollSeq *pColl){
CollSeq *pColl2;
char *z = pColl->zName;
int i;
static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 };
for(i=0; i<3; i++){
pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0);
if( pColl2->xCmp!=0 ){
memcpy(pColl, pColl2, sizeof(CollSeq));
pColl->xDel = 0; /* Do not copy the destructor */
return SQLITE_OK;
}
}
return SQLITE_ERROR;
}
/*
** This function is responsible for invoking the collation factory callback
** or substituting a collation sequence of a different encoding when the
** requested collation sequence is not available in the desired encoding.
**
** If it is not NULL, then pColl must point to the database native encoding
** collation sequence with name zName, length nName.
**
** The return value is either the collation sequence to be used in database
** db for collation type name zName, length nName, or NULL, if no collation
** sequence can be found. If no collation is found, leave an error message.
**
** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
*/
CollSeq *sqlite3GetCollSeq(
Parse *pParse, /* Parsing context */
u8 enc, /* The desired encoding for the collating sequence */
CollSeq *pColl, /* Collating sequence with native encoding, or NULL */
const char *zName /* Collating sequence name */
){
CollSeq *p;
sqlite3 *db = pParse->db;
p = pColl;
if( !p ){
p = sqlite3FindCollSeq(db, enc, zName, 0);
}
if( !p || !p->xCmp ){
/* No collation sequence of this type for this encoding is registered.
** Call the collation factory to see if it can supply us with one.
*/
callCollNeeded(db, enc, zName);
p = sqlite3FindCollSeq(db, enc, zName, 0);
}
if( p && !p->xCmp && synthCollSeq(db, p) ){
p = 0;
}
assert( !p || p->xCmp );
if( p==0 ){
sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
}
return p;
}
/*
** This routine is called on a collation sequence before it is used to
** check that it is defined. An undefined collation sequence exists when
** a database is loaded that contains references to collation sequences
** that have not been defined by sqlite3_create_collation() etc.
**
** If required, this routine calls the 'collation needed' callback to
** request a definition of the collating sequence. If this doesn't work,
** an equivalent collating sequence that uses a text encoding different
** from the main database is substituted, if one is available.
*/
int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){
if( pColl ){
const char *zName = pColl->zName;
sqlite3 *db = pParse->db;
CollSeq *p = sqlite3GetCollSeq(pParse, ENC(db), pColl, zName);
if( !p ){
return SQLITE_ERROR;
}
assert( p==pColl );
}
return SQLITE_OK;
}
/*
** Locate and return an entry from the db.aCollSeq hash table. If the entry
** specified by zName and nName is not found and parameter 'create' is
** true, then create a new entry. Otherwise return NULL.
**
** Each pointer stored in the sqlite3.aCollSeq hash table contains an
** array of three CollSeq structures. The first is the collation sequence
** preferred for UTF-8, the second UTF-16le, and the third UTF-16be.
**
** Stored immediately after the three collation sequences is a copy of
** the collation sequence name. A pointer to this string is stored in
** each collation sequence structure.
*/
static CollSeq *findCollSeqEntry(
sqlite3 *db, /* Database connection */
const char *zName, /* Name of the collating sequence */
int create /* Create a new entry if true */
){
CollSeq *pColl;
pColl = sqlite3HashFind(&db->aCollSeq, zName);
if( 0==pColl && create ){
int nName = sqlite3Strlen30(zName);
pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName + 1);
if( pColl ){
CollSeq *pDel = 0;
pColl[0].zName = (char*)&pColl[3];
pColl[0].enc = SQLITE_UTF8;
pColl[1].zName = (char*)&pColl[3];
pColl[1].enc = SQLITE_UTF16LE;
pColl[2].zName = (char*)&pColl[3];
pColl[2].enc = SQLITE_UTF16BE;
memcpy(pColl[0].zName, zName, nName);
pColl[0].zName[nName] = 0;
pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, pColl);
/* If a malloc() failure occurred in sqlite3HashInsert(), it will
** return the pColl pointer to be deleted (because it wasn't added
** to the hash table).
*/
assert( pDel==0 || pDel==pColl );
if( pDel!=0 ){
sqlite3OomFault(db);
sqlite3DbFree(db, pDel);
pColl = 0;
}
}
}
return pColl;
}
/*
** Parameter zName points to a UTF-8 encoded string nName bytes long.
** Return the CollSeq* pointer for the collation sequence named zName
** for the encoding 'enc' from the database 'db'.
**
** If the entry specified is not found and 'create' is true, then create a
** new entry. Otherwise return NULL.
**
** A separate function sqlite3LocateCollSeq() is a wrapper around
** this routine. sqlite3LocateCollSeq() invokes the collation factory
** if necessary and generates an error message if the collating sequence
** cannot be found.
**
** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
*/
CollSeq *sqlite3FindCollSeq(
sqlite3 *db,
u8 enc,
const char *zName,
int create
){
CollSeq *pColl;
if( zName ){
pColl = findCollSeqEntry(db, zName, create);
}else{
pColl = db->pDfltColl;
}
assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
if( pColl ) pColl += enc-1;
return pColl;
}
/* During the search for the best function definition, this procedure
** is called to test how well the function passed as the first argument
** matches the request for a function with nArg arguments in a system
** that uses encoding enc. The value returned indicates how well the
** request is matched. A higher value indicates a better match.
**
** If nArg is -1 that means to only return a match (non-zero) if p->nArg
** is also -1. In other words, we are searching for a function that
** takes a variable number of arguments.
**
** If nArg is -2 that means that we are searching for any function
** regardless of the number of arguments it uses, so return a positive
** match score for any
**
** The returned value is always between 0 and 6, as follows:
**
** 0: Not a match.
** 1: UTF8/16 conversion required and function takes any number of arguments.
** 2: UTF16 byte order change required and function takes any number of args.
** 3: encoding matches and function takes any number of arguments
** 4: UTF8/16 conversion required - argument count matches exactly
** 5: UTF16 byte order conversion required - argument count matches exactly
** 6: Perfect match: encoding and argument count match exactly.
**
** If nArg==(-2) then any function with a non-null xSFunc is
** a perfect match and any function with xSFunc NULL is
** a non-match.
*/
#define FUNC_PERFECT_MATCH 6 /* The score for a perfect match */
static int matchQuality(
FuncDef *p, /* The function we are evaluating for match quality */
int nArg, /* Desired number of arguments. (-1)==any */
u8 enc /* Desired text encoding */
){
int match;
/* nArg of -2 is a special case */
if( nArg==(-2) ) return (p->xSFunc==0) ? 0 : FUNC_PERFECT_MATCH;
/* Wrong number of arguments means "no match" */
if( p->nArg!=nArg && p->nArg>=0 ) return 0;
/* Give a better score to a function with a specific number of arguments
** than to function that accepts any number of arguments. */
if( p->nArg==nArg ){
match = 4;
}else{
match = 1;
}
/* Bonus points if the text encoding matches */
if( enc==(p->funcFlags & SQLITE_FUNC_ENCMASK) ){
match += 2; /* Exact encoding match */
}else if( (enc & p->funcFlags & 2)!=0 ){
match += 1; /* Both are UTF16, but with different byte orders */
}
return match;
}
/*
** Search a FuncDefHash for a function with the given name. Return
** a pointer to the matching FuncDef if found, or 0 if there is no match.
*/
static FuncDef *functionSearch(
int h, /* Hash of the name */
const char *zFunc /* Name of function */
){
FuncDef *p;
for(p=sqlite3BuiltinFunctions.a[h]; p; p=p->u.pHash){
if( sqlite3StrICmp(p->zName, zFunc)==0 ){
return p;
}
}
return 0;
}
/*
** Insert a new FuncDef into a FuncDefHash hash table.
*/
void sqlite3InsertBuiltinFuncs(
FuncDef *aDef, /* List of global functions to be inserted */
int nDef /* Length of the apDef[] list */
){
int i;
for(i=0; i<nDef; i++){
FuncDef *pOther;
const char *zName = aDef[i].zName;
int nName = sqlite3Strlen30(zName);
int h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % SQLITE_FUNC_HASH_SZ;
pOther = functionSearch(h, zName);
if( pOther ){
assert( pOther!=&aDef[i] && pOther->pNext!=&aDef[i] );
aDef[i].pNext = pOther->pNext;
pOther->pNext = &aDef[i];
}else{
aDef[i].pNext = 0;
aDef[i].u.pHash = sqlite3BuiltinFunctions.a[h];
sqlite3BuiltinFunctions.a[h] = &aDef[i];
}
}
}
/*
** Locate a user function given a name, a number of arguments and a flag
** indicating whether the function prefers UTF-16 over UTF-8. Return a
** pointer to the FuncDef structure that defines that function, or return
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.
**
** If nArg is -2, then the first valid function found is returned. A
** function is valid if xSFunc is non-zero. The nArg==(-2)
** case is used to see if zName is a valid function name for some number
** of arguments. If nArg is -2, then createFlag must be 0.
**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
FuncDef *sqlite3FindFunction(
sqlite3 *db, /* An open database */
const char *zName, /* Name of the function. zero-terminated */
int nArg, /* Number of arguments. -1 means any number */
u8 enc, /* Preferred text encoding */
u8 createFlag /* Create new entry if true and does not otherwise exist */
){
FuncDef *p; /* Iterator variable */
FuncDef *pBest = 0; /* Best match found so far */
int bestScore = 0; /* Score of best match */
int h; /* Hash value */
int nName; /* Length of the name */
assert( nArg>=(-2) );
assert( nArg>=(-1) || createFlag==0 );
nName = sqlite3Strlen30(zName);
/* First search for a match amongst the application-defined functions.
*/
p = (FuncDef*)sqlite3HashFind(&db->aFunc, zName);
while( p ){
int score = matchQuality(p, nArg, enc);
if( score>bestScore ){
pBest = p;
bestScore = score;
}
p = p->pNext;
}
/* If no match is found, search the built-in functions.
**
** If the SQLITE_PreferBuiltin flag is set, then search the built-in
** functions even if a prior app-defined function was found. And give
** priority to built-in functions.
**
** Except, if createFlag is true, that means that we are trying to
** install a new function. Whatever FuncDef structure is returned it will
** have fields overwritten with new information appropriate for the
** new function. But the FuncDefs for built-in functions are read-only.
** So we must not search for built-ins when creating a new function.
*/
if( !createFlag && (pBest==0 || (db->flags & SQLITE_PreferBuiltin)!=0) ){
bestScore = 0;
h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % SQLITE_FUNC_HASH_SZ;
p = functionSearch(h, zName);
while( p ){
int score = matchQuality(p, nArg, enc);
if( score>bestScore ){
pBest = p;
bestScore = score;
}
p = p->pNext;
}
}
/* If the createFlag parameter is true and the search did not reveal an
** exact match for the name, number of arguments and encoding, then add a
** new entry to the hash table and return it.
*/
if( createFlag && bestScore<FUNC_PERFECT_MATCH &&
(pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
FuncDef *pOther;
pBest->zName = (const char*)&pBest[1];
pBest->nArg = (u16)nArg;
pBest->funcFlags = enc;
memcpy((char*)&pBest[1], zName, nName+1);
pOther = (FuncDef*)sqlite3HashInsert(&db->aFunc, pBest->zName, pBest);
if( pOther==pBest ){
sqlite3DbFree(db, pBest);
sqlite3OomFault(db);
return 0;
}else{
pBest->pNext = pOther;
}
}
if( pBest && (pBest->xSFunc || createFlag) ){
return pBest;
}
return 0;
}
/*
** Free all resources held by the schema structure. The void* argument points
** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the
** pointer itself, it just cleans up subsidiary resources (i.e. the contents
** of the schema hash tables).
**
** The Schema.cache_size variable is not cleared.
*/
void sqlite3SchemaClear(void *p){
Hash temp1;
Hash temp2;
HashElem *pElem;
Schema *pSchema = (Schema *)p;
temp1 = pSchema->tblHash;
temp2 = pSchema->trigHash;
sqlite3HashInit(&pSchema->trigHash);
sqlite3HashClear(&pSchema->idxHash);
for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem));
}
sqlite3HashClear(&temp2);
sqlite3HashInit(&pSchema->tblHash);
for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
Table *pTab = sqliteHashData(pElem);
sqlite3DeleteTable(0, pTab);
}
sqlite3HashClear(&temp1);
sqlite3HashClear(&pSchema->fkeyHash);
pSchema->pSeqTab = 0;
if( pSchema->schemaFlags & DB_SchemaLoaded ){
pSchema->iGeneration++;
pSchema->schemaFlags &= ~DB_SchemaLoaded;
}
}
/*
** Find and return the schema associated with a BTree. Create
** a new one if necessary.
*/
Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){
Schema * p;
if( pBt ){
p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear);
}else{
p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema));
}
if( !p ){
sqlite3OomFault(db);
}else if ( 0==p->file_format ){
sqlite3HashInit(&p->tblHash);
sqlite3HashInit(&p->idxHash);
sqlite3HashInit(&p->trigHash);
sqlite3HashInit(&p->fkeyHash);
p->enc = SQLITE_UTF8;
}
return p;
}