xref: /sqlite-3.40.0/src/main.c (revision 4dfe98a8)
1 /*
2 ** 2001 September 15
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 ** Main file for the SQLite library.  The routines in this file
13 ** implement the programmer interface to the library.  Routines in
14 ** other files are for internal use by SQLite and should not be
15 ** accessed by users of the library.
16 */
17 #include "sqliteInt.h"
18 
19 #ifdef SQLITE_ENABLE_FTS3
20 # include "fts3.h"
21 #endif
22 #ifdef SQLITE_ENABLE_RTREE
23 # include "rtree.h"
24 #endif
25 #ifdef SQLITE_ENABLE_ICU
26 # include "sqliteicu.h"
27 #endif
28 
29 #ifndef SQLITE_AMALGAMATION
30 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
31 ** contains the text of SQLITE_VERSION macro.
32 */
33 const char sqlite3_version[] = SQLITE_VERSION;
34 #endif
35 
36 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
37 ** a pointer to the to the sqlite3_version[] string constant.
38 */
39 const char *sqlite3_libversion(void){ return sqlite3_version; }
40 
41 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
42 ** pointer to a string constant whose value is the same as the
43 ** SQLITE_SOURCE_ID C preprocessor macro.
44 */
45 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
46 
47 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
48 ** returns an integer equal to SQLITE_VERSION_NUMBER.
49 */
50 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
51 
52 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
53 ** zero if and only if SQLite was compiled with mutexing code omitted due to
54 ** the SQLITE_THREADSAFE compile-time option being set to 0.
55 */
56 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
57 
58 /*
59 ** When compiling the test fixture or with debugging enabled (on Win32),
60 ** this variable being set to non-zero will cause OSTRACE macros to emit
61 ** extra diagnostic information.
62 */
63 #ifdef SQLITE_HAVE_OS_TRACE
64 # ifndef SQLITE_DEBUG_OS_TRACE
65 #   define SQLITE_DEBUG_OS_TRACE 0
66 # endif
67   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
68 #endif
69 
70 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
71 /*
72 ** If the following function pointer is not NULL and if
73 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
74 ** I/O active are written using this function.  These messages
75 ** are intended for debugging activity only.
76 */
77 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
78 #endif
79 
80 /*
81 ** If the following global variable points to a string which is the
82 ** name of a directory, then that directory will be used to store
83 ** temporary files.
84 **
85 ** See also the "PRAGMA temp_store_directory" SQL command.
86 */
87 char *sqlite3_temp_directory = 0;
88 
89 /*
90 ** If the following global variable points to a string which is the
91 ** name of a directory, then that directory will be used to store
92 ** all database files specified with a relative pathname.
93 **
94 ** See also the "PRAGMA data_store_directory" SQL command.
95 */
96 char *sqlite3_data_directory = 0;
97 
98 /*
99 ** Initialize SQLite.
100 **
101 ** This routine must be called to initialize the memory allocation,
102 ** VFS, and mutex subsystems prior to doing any serious work with
103 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
104 ** this routine will be called automatically by key routines such as
105 ** sqlite3_open().
106 **
107 ** This routine is a no-op except on its very first call for the process,
108 ** or for the first call after a call to sqlite3_shutdown.
109 **
110 ** The first thread to call this routine runs the initialization to
111 ** completion.  If subsequent threads call this routine before the first
112 ** thread has finished the initialization process, then the subsequent
113 ** threads must block until the first thread finishes with the initialization.
114 **
115 ** The first thread might call this routine recursively.  Recursive
116 ** calls to this routine should not block, of course.  Otherwise the
117 ** initialization process would never complete.
118 **
119 ** Let X be the first thread to enter this routine.  Let Y be some other
120 ** thread.  Then while the initial invocation of this routine by X is
121 ** incomplete, it is required that:
122 **
123 **    *  Calls to this routine from Y must block until the outer-most
124 **       call by X completes.
125 **
126 **    *  Recursive calls to this routine from thread X return immediately
127 **       without blocking.
128 */
129 int sqlite3_initialize(void){
130   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
131   int rc;                                      /* Result code */
132 #ifdef SQLITE_EXTRA_INIT
133   int bRunExtraInit = 0;                       /* Extra initialization needed */
134 #endif
135 
136 #ifdef SQLITE_OMIT_WSD
137   rc = sqlite3_wsd_init(4096, 24);
138   if( rc!=SQLITE_OK ){
139     return rc;
140   }
141 #endif
142 
143   /* If the following assert() fails on some obscure processor/compiler
144   ** combination, the work-around is to set the correct pointer
145   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
146   assert( SQLITE_PTRSIZE==sizeof(char*) );
147 
148   /* If SQLite is already completely initialized, then this call
149   ** to sqlite3_initialize() should be a no-op.  But the initialization
150   ** must be complete.  So isInit must not be set until the very end
151   ** of this routine.
152   */
153   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
154 
155   /* Make sure the mutex subsystem is initialized.  If unable to
156   ** initialize the mutex subsystem, return early with the error.
157   ** If the system is so sick that we are unable to allocate a mutex,
158   ** there is not much SQLite is going to be able to do.
159   **
160   ** The mutex subsystem must take care of serializing its own
161   ** initialization.
162   */
163   rc = sqlite3MutexInit();
164   if( rc ) return rc;
165 
166   /* Initialize the malloc() system and the recursive pInitMutex mutex.
167   ** This operation is protected by the STATIC_MASTER mutex.  Note that
168   ** MutexAlloc() is called for a static mutex prior to initializing the
169   ** malloc subsystem - this implies that the allocation of a static
170   ** mutex must not require support from the malloc subsystem.
171   */
172   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
173   sqlite3_mutex_enter(pMaster);
174   sqlite3GlobalConfig.isMutexInit = 1;
175   if( !sqlite3GlobalConfig.isMallocInit ){
176     rc = sqlite3MallocInit();
177   }
178   if( rc==SQLITE_OK ){
179     sqlite3GlobalConfig.isMallocInit = 1;
180     if( !sqlite3GlobalConfig.pInitMutex ){
181       sqlite3GlobalConfig.pInitMutex =
182            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
183       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
184         rc = SQLITE_NOMEM;
185       }
186     }
187   }
188   if( rc==SQLITE_OK ){
189     sqlite3GlobalConfig.nRefInitMutex++;
190   }
191   sqlite3_mutex_leave(pMaster);
192 
193   /* If rc is not SQLITE_OK at this point, then either the malloc
194   ** subsystem could not be initialized or the system failed to allocate
195   ** the pInitMutex mutex. Return an error in either case.  */
196   if( rc!=SQLITE_OK ){
197     return rc;
198   }
199 
200   /* Do the rest of the initialization under the recursive mutex so
201   ** that we will be able to handle recursive calls into
202   ** sqlite3_initialize().  The recursive calls normally come through
203   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
204   ** recursive calls might also be possible.
205   **
206   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
207   ** to the xInit method, so the xInit method need not be threadsafe.
208   **
209   ** The following mutex is what serializes access to the appdef pcache xInit
210   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
211   ** call to sqlite3PcacheInitialize().
212   */
213   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
214   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
215     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
216     sqlite3GlobalConfig.inProgress = 1;
217     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
218     sqlite3RegisterGlobalFunctions();
219     if( sqlite3GlobalConfig.isPCacheInit==0 ){
220       rc = sqlite3PcacheInitialize();
221     }
222     if( rc==SQLITE_OK ){
223       sqlite3GlobalConfig.isPCacheInit = 1;
224       rc = sqlite3OsInit();
225     }
226     if( rc==SQLITE_OK ){
227       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
228           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
229       sqlite3GlobalConfig.isInit = 1;
230 #ifdef SQLITE_EXTRA_INIT
231       bRunExtraInit = 1;
232 #endif
233     }
234     sqlite3GlobalConfig.inProgress = 0;
235   }
236   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
237 
238   /* Go back under the static mutex and clean up the recursive
239   ** mutex to prevent a resource leak.
240   */
241   sqlite3_mutex_enter(pMaster);
242   sqlite3GlobalConfig.nRefInitMutex--;
243   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
244     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
245     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
246     sqlite3GlobalConfig.pInitMutex = 0;
247   }
248   sqlite3_mutex_leave(pMaster);
249 
250   /* The following is just a sanity check to make sure SQLite has
251   ** been compiled correctly.  It is important to run this code, but
252   ** we don't want to run it too often and soak up CPU cycles for no
253   ** reason.  So we run it once during initialization.
254   */
255 #ifndef NDEBUG
256 #ifndef SQLITE_OMIT_FLOATING_POINT
257   /* This section of code's only "output" is via assert() statements. */
258   if ( rc==SQLITE_OK ){
259     u64 x = (((u64)1)<<63)-1;
260     double y;
261     assert(sizeof(x)==8);
262     assert(sizeof(x)==sizeof(y));
263     memcpy(&y, &x, 8);
264     assert( sqlite3IsNaN(y) );
265   }
266 #endif
267 #endif
268 
269   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
270   ** compile-time option.
271   */
272 #ifdef SQLITE_EXTRA_INIT
273   if( bRunExtraInit ){
274     int SQLITE_EXTRA_INIT(const char*);
275     rc = SQLITE_EXTRA_INIT(0);
276   }
277 #endif
278 
279   return rc;
280 }
281 
282 /*
283 ** Undo the effects of sqlite3_initialize().  Must not be called while
284 ** there are outstanding database connections or memory allocations or
285 ** while any part of SQLite is otherwise in use in any thread.  This
286 ** routine is not threadsafe.  But it is safe to invoke this routine
287 ** on when SQLite is already shut down.  If SQLite is already shut down
288 ** when this routine is invoked, then this routine is a harmless no-op.
289 */
290 int sqlite3_shutdown(void){
291 #ifdef SQLITE_OMIT_WSD
292   int rc = sqlite3_wsd_init(4096, 24);
293   if( rc!=SQLITE_OK ){
294     return rc;
295   }
296 #endif
297 
298   if( sqlite3GlobalConfig.isInit ){
299 #ifdef SQLITE_EXTRA_SHUTDOWN
300     void SQLITE_EXTRA_SHUTDOWN(void);
301     SQLITE_EXTRA_SHUTDOWN();
302 #endif
303     sqlite3_os_end();
304     sqlite3_reset_auto_extension();
305     sqlite3GlobalConfig.isInit = 0;
306   }
307   if( sqlite3GlobalConfig.isPCacheInit ){
308     sqlite3PcacheShutdown();
309     sqlite3GlobalConfig.isPCacheInit = 0;
310   }
311   if( sqlite3GlobalConfig.isMallocInit ){
312     sqlite3MallocEnd();
313     sqlite3GlobalConfig.isMallocInit = 0;
314 
315 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
316     /* The heap subsystem has now been shutdown and these values are supposed
317     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
318     ** which would rely on that heap subsystem; therefore, make sure these
319     ** values cannot refer to heap memory that was just invalidated when the
320     ** heap subsystem was shutdown.  This is only done if the current call to
321     ** this function resulted in the heap subsystem actually being shutdown.
322     */
323     sqlite3_data_directory = 0;
324     sqlite3_temp_directory = 0;
325 #endif
326   }
327   if( sqlite3GlobalConfig.isMutexInit ){
328     sqlite3MutexEnd();
329     sqlite3GlobalConfig.isMutexInit = 0;
330   }
331 
332   return SQLITE_OK;
333 }
334 
335 /*
336 ** This API allows applications to modify the global configuration of
337 ** the SQLite library at run-time.
338 **
339 ** This routine should only be called when there are no outstanding
340 ** database connections or memory allocations.  This routine is not
341 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
342 ** behavior.
343 */
344 int sqlite3_config(int op, ...){
345   va_list ap;
346   int rc = SQLITE_OK;
347 
348   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
349   ** the SQLite library is in use. */
350   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
351 
352   va_start(ap, op);
353   switch( op ){
354 
355     /* Mutex configuration options are only available in a threadsafe
356     ** compile.
357     */
358 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
359     case SQLITE_CONFIG_SINGLETHREAD: {
360       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
361       ** Single-thread. */
362       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
363       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
364       break;
365     }
366 #endif
367 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
368     case SQLITE_CONFIG_MULTITHREAD: {
369       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
370       ** Multi-thread. */
371       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
372       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
373       break;
374     }
375 #endif
376 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
377     case SQLITE_CONFIG_SERIALIZED: {
378       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
379       ** Serialized. */
380       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
381       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
382       break;
383     }
384 #endif
385 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
386     case SQLITE_CONFIG_MUTEX: {
387       /* Specify an alternative mutex implementation */
388       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
389       break;
390     }
391 #endif
392 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
393     case SQLITE_CONFIG_GETMUTEX: {
394       /* Retrieve the current mutex implementation */
395       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
396       break;
397     }
398 #endif
399 
400     case SQLITE_CONFIG_MALLOC: {
401       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
402       ** single argument which is a pointer to an instance of the
403       ** sqlite3_mem_methods structure. The argument specifies alternative
404       ** low-level memory allocation routines to be used in place of the memory
405       ** allocation routines built into SQLite. */
406       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
407       break;
408     }
409     case SQLITE_CONFIG_GETMALLOC: {
410       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
411       ** single argument which is a pointer to an instance of the
412       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
413       ** filled with the currently defined memory allocation routines. */
414       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
415       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
416       break;
417     }
418     case SQLITE_CONFIG_MEMSTATUS: {
419       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
420       ** single argument of type int, interpreted as a boolean, which enables
421       ** or disables the collection of memory allocation statistics. */
422       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
423       break;
424     }
425     case SQLITE_CONFIG_SCRATCH: {
426       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
427       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
428       ** which the scratch allocations will be drawn, the size of each scratch
429       ** allocation (sz), and the maximum number of scratch allocations (N). */
430       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
431       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
432       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
433       break;
434     }
435     case SQLITE_CONFIG_PAGECACHE: {
436       /* EVIDENCE-OF: R-31408-40510 There are three arguments to
437       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size
438       ** of each page buffer (sz), and the number of pages (N). */
439       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
440       sqlite3GlobalConfig.szPage = va_arg(ap, int);
441       sqlite3GlobalConfig.nPage = va_arg(ap, int);
442       break;
443     }
444     case SQLITE_CONFIG_PCACHE_HDRSZ: {
445       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
446       ** a single parameter which is a pointer to an integer and writes into
447       ** that integer the number of extra bytes per page required for each page
448       ** in SQLITE_CONFIG_PAGECACHE. */
449       *va_arg(ap, int*) =
450           sqlite3HeaderSizeBtree() +
451           sqlite3HeaderSizePcache() +
452           sqlite3HeaderSizePcache1();
453       break;
454     }
455 
456     case SQLITE_CONFIG_PCACHE: {
457       /* no-op */
458       break;
459     }
460     case SQLITE_CONFIG_GETPCACHE: {
461       /* now an error */
462       rc = SQLITE_ERROR;
463       break;
464     }
465 
466     case SQLITE_CONFIG_PCACHE2: {
467       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
468       ** single argument which is a pointer to an sqlite3_pcache_methods2
469       ** object. This object specifies the interface to a custom page cache
470       ** implementation. */
471       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
472       break;
473     }
474     case SQLITE_CONFIG_GETPCACHE2: {
475       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
476       ** single argument which is a pointer to an sqlite3_pcache_methods2
477       ** object. SQLite copies of the current page cache implementation into
478       ** that object. */
479       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
480         sqlite3PCacheSetDefault();
481       }
482       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
483       break;
484     }
485 
486 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
487 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
488 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
489 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
490     case SQLITE_CONFIG_HEAP: {
491       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
492       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
493       ** number of bytes in the memory buffer, and the minimum allocation size.
494       */
495       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
496       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
497       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
498 
499       if( sqlite3GlobalConfig.mnReq<1 ){
500         sqlite3GlobalConfig.mnReq = 1;
501       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
502         /* cap min request size at 2^12 */
503         sqlite3GlobalConfig.mnReq = (1<<12);
504       }
505 
506       if( sqlite3GlobalConfig.pHeap==0 ){
507         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
508         ** is NULL, then SQLite reverts to using its default memory allocator
509         ** (the system malloc() implementation), undoing any prior invocation of
510         ** SQLITE_CONFIG_MALLOC.
511         **
512         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
513         ** revert to its default implementation when sqlite3_initialize() is run
514         */
515         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
516       }else{
517         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
518         ** alternative memory allocator is engaged to handle all of SQLites
519         ** memory allocation needs. */
520 #ifdef SQLITE_ENABLE_MEMSYS3
521         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
522 #endif
523 #ifdef SQLITE_ENABLE_MEMSYS5
524         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
525 #endif
526       }
527       break;
528     }
529 #endif
530 
531     case SQLITE_CONFIG_LOOKASIDE: {
532       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
533       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
534       break;
535     }
536 
537     /* Record a pointer to the logger function and its first argument.
538     ** The default is NULL.  Logging is disabled if the function pointer is
539     ** NULL.
540     */
541     case SQLITE_CONFIG_LOG: {
542       /* MSVC is picky about pulling func ptrs from va lists.
543       ** http://support.microsoft.com/kb/47961
544       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
545       */
546       typedef void(*LOGFUNC_t)(void*,int,const char*);
547       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
548       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
549       break;
550     }
551 
552     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
553     ** can be changed at start-time using the
554     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
555     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
556     */
557     case SQLITE_CONFIG_URI: {
558       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
559       ** argument of type int. If non-zero, then URI handling is globally
560       ** enabled. If the parameter is zero, then URI handling is globally
561       ** disabled. */
562       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
563       break;
564     }
565 
566     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
567       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
568       ** option takes a single integer argument which is interpreted as a
569       ** boolean in order to enable or disable the use of covering indices for
570       ** full table scans in the query optimizer. */
571       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
572       break;
573     }
574 
575 #ifdef SQLITE_ENABLE_SQLLOG
576     case SQLITE_CONFIG_SQLLOG: {
577       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
578       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
579       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
580       break;
581     }
582 #endif
583 
584     case SQLITE_CONFIG_MMAP_SIZE: {
585       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
586       ** integer (sqlite3_int64) values that are the default mmap size limit
587       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
588       ** mmap size limit. */
589       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
590       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
591       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
592       ** negative, then that argument is changed to its compile-time default.
593       **
594       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
595       ** silently truncated if necessary so that it does not exceed the
596       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
597       ** compile-time option.
598       */
599       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
600         mxMmap = SQLITE_MAX_MMAP_SIZE;
601       }
602       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
603       if( szMmap>mxMmap) szMmap = mxMmap;
604       sqlite3GlobalConfig.mxMmap = mxMmap;
605       sqlite3GlobalConfig.szMmap = szMmap;
606       break;
607     }
608 
609 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
610     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
611       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
612       ** unsigned integer value that specifies the maximum size of the created
613       ** heap. */
614       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
615       break;
616     }
617 #endif
618 
619     case SQLITE_CONFIG_PMASZ: {
620       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
621       break;
622     }
623 
624     default: {
625       rc = SQLITE_ERROR;
626       break;
627     }
628   }
629   va_end(ap);
630   return rc;
631 }
632 
633 /*
634 ** Set up the lookaside buffers for a database connection.
635 ** Return SQLITE_OK on success.
636 ** If lookaside is already active, return SQLITE_BUSY.
637 **
638 ** The sz parameter is the number of bytes in each lookaside slot.
639 ** The cnt parameter is the number of slots.  If pStart is NULL the
640 ** space for the lookaside memory is obtained from sqlite3_malloc().
641 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
642 ** the lookaside memory.
643 */
644 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
645 #ifndef SQLITE_OMIT_LOOKASIDE
646   void *pStart;
647   if( db->lookaside.nOut ){
648     return SQLITE_BUSY;
649   }
650   /* Free any existing lookaside buffer for this handle before
651   ** allocating a new one so we don't have to have space for
652   ** both at the same time.
653   */
654   if( db->lookaside.bMalloced ){
655     sqlite3_free(db->lookaside.pStart);
656   }
657   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
658   ** than a pointer to be useful.
659   */
660   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
661   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
662   if( cnt<0 ) cnt = 0;
663   if( sz==0 || cnt==0 ){
664     sz = 0;
665     pStart = 0;
666   }else if( pBuf==0 ){
667     sqlite3BeginBenignMalloc();
668     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
669     sqlite3EndBenignMalloc();
670     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
671   }else{
672     pStart = pBuf;
673   }
674   db->lookaside.pStart = pStart;
675   db->lookaside.pFree = 0;
676   db->lookaside.sz = (u16)sz;
677   if( pStart ){
678     int i;
679     LookasideSlot *p;
680     assert( sz > (int)sizeof(LookasideSlot*) );
681     p = (LookasideSlot*)pStart;
682     for(i=cnt-1; i>=0; i--){
683       p->pNext = db->lookaside.pFree;
684       db->lookaside.pFree = p;
685       p = (LookasideSlot*)&((u8*)p)[sz];
686     }
687     db->lookaside.pEnd = p;
688     db->lookaside.bEnabled = 1;
689     db->lookaside.bMalloced = pBuf==0 ?1:0;
690   }else{
691     db->lookaside.pStart = db;
692     db->lookaside.pEnd = db;
693     db->lookaside.bEnabled = 0;
694     db->lookaside.bMalloced = 0;
695   }
696 #endif /* SQLITE_OMIT_LOOKASIDE */
697   return SQLITE_OK;
698 }
699 
700 /*
701 ** Return the mutex associated with a database connection.
702 */
703 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
704 #ifdef SQLITE_ENABLE_API_ARMOR
705   if( !sqlite3SafetyCheckOk(db) ){
706     (void)SQLITE_MISUSE_BKPT;
707     return 0;
708   }
709 #endif
710   return db->mutex;
711 }
712 
713 /*
714 ** Free up as much memory as we can from the given database
715 ** connection.
716 */
717 int sqlite3_db_release_memory(sqlite3 *db){
718   int i;
719 
720 #ifdef SQLITE_ENABLE_API_ARMOR
721   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
722 #endif
723   sqlite3_mutex_enter(db->mutex);
724   sqlite3BtreeEnterAll(db);
725   for(i=0; i<db->nDb; i++){
726     Btree *pBt = db->aDb[i].pBt;
727     if( pBt ){
728       Pager *pPager = sqlite3BtreePager(pBt);
729       sqlite3PagerShrink(pPager);
730     }
731   }
732   sqlite3BtreeLeaveAll(db);
733   sqlite3_mutex_leave(db->mutex);
734   return SQLITE_OK;
735 }
736 
737 /*
738 ** Configuration settings for an individual database connection
739 */
740 int sqlite3_db_config(sqlite3 *db, int op, ...){
741   va_list ap;
742   int rc;
743   va_start(ap, op);
744   switch( op ){
745     case SQLITE_DBCONFIG_LOOKASIDE: {
746       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
747       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
748       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
749       rc = setupLookaside(db, pBuf, sz, cnt);
750       break;
751     }
752     default: {
753       static const struct {
754         int op;      /* The opcode */
755         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
756       } aFlagOp[] = {
757         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
758         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
759       };
760       unsigned int i;
761       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
762       for(i=0; i<ArraySize(aFlagOp); i++){
763         if( aFlagOp[i].op==op ){
764           int onoff = va_arg(ap, int);
765           int *pRes = va_arg(ap, int*);
766           int oldFlags = db->flags;
767           if( onoff>0 ){
768             db->flags |= aFlagOp[i].mask;
769           }else if( onoff==0 ){
770             db->flags &= ~aFlagOp[i].mask;
771           }
772           if( oldFlags!=db->flags ){
773             sqlite3ExpirePreparedStatements(db);
774           }
775           if( pRes ){
776             *pRes = (db->flags & aFlagOp[i].mask)!=0;
777           }
778           rc = SQLITE_OK;
779           break;
780         }
781       }
782       break;
783     }
784   }
785   va_end(ap);
786   return rc;
787 }
788 
789 
790 /*
791 ** Return true if the buffer z[0..n-1] contains all spaces.
792 */
793 static int allSpaces(const char *z, int n){
794   while( n>0 && z[n-1]==' ' ){ n--; }
795   return n==0;
796 }
797 
798 /*
799 ** This is the default collating function named "BINARY" which is always
800 ** available.
801 **
802 ** If the padFlag argument is not NULL then space padding at the end
803 ** of strings is ignored.  This implements the RTRIM collation.
804 */
805 static int binCollFunc(
806   void *padFlag,
807   int nKey1, const void *pKey1,
808   int nKey2, const void *pKey2
809 ){
810   int rc, n;
811   n = nKey1<nKey2 ? nKey1 : nKey2;
812   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
813   ** strings byte by byte using the memcmp() function from the standard C
814   ** library. */
815   rc = memcmp(pKey1, pKey2, n);
816   if( rc==0 ){
817     if( padFlag
818      && allSpaces(((char*)pKey1)+n, nKey1-n)
819      && allSpaces(((char*)pKey2)+n, nKey2-n)
820     ){
821       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
822       ** spaces at the end of either string do not change the result. In other
823       ** words, strings will compare equal to one another as long as they
824       ** differ only in the number of spaces at the end.
825       */
826     }else{
827       rc = nKey1 - nKey2;
828     }
829   }
830   return rc;
831 }
832 
833 /*
834 ** Another built-in collating sequence: NOCASE.
835 **
836 ** This collating sequence is intended to be used for "case independent
837 ** comparison". SQLite's knowledge of upper and lower case equivalents
838 ** extends only to the 26 characters used in the English language.
839 **
840 ** At the moment there is only a UTF-8 implementation.
841 */
842 static int nocaseCollatingFunc(
843   void *NotUsed,
844   int nKey1, const void *pKey1,
845   int nKey2, const void *pKey2
846 ){
847   int r = sqlite3StrNICmp(
848       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
849   UNUSED_PARAMETER(NotUsed);
850   if( 0==r ){
851     r = nKey1-nKey2;
852   }
853   return r;
854 }
855 
856 /*
857 ** Return the ROWID of the most recent insert
858 */
859 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
860 #ifdef SQLITE_ENABLE_API_ARMOR
861   if( !sqlite3SafetyCheckOk(db) ){
862     (void)SQLITE_MISUSE_BKPT;
863     return 0;
864   }
865 #endif
866   return db->lastRowid;
867 }
868 
869 /*
870 ** Return the number of changes in the most recent call to sqlite3_exec().
871 */
872 int sqlite3_changes(sqlite3 *db){
873 #ifdef SQLITE_ENABLE_API_ARMOR
874   if( !sqlite3SafetyCheckOk(db) ){
875     (void)SQLITE_MISUSE_BKPT;
876     return 0;
877   }
878 #endif
879   return db->nChange;
880 }
881 
882 /*
883 ** Return the number of changes since the database handle was opened.
884 */
885 int sqlite3_total_changes(sqlite3 *db){
886 #ifdef SQLITE_ENABLE_API_ARMOR
887   if( !sqlite3SafetyCheckOk(db) ){
888     (void)SQLITE_MISUSE_BKPT;
889     return 0;
890   }
891 #endif
892   return db->nTotalChange;
893 }
894 
895 /*
896 ** Close all open savepoints. This function only manipulates fields of the
897 ** database handle object, it does not close any savepoints that may be open
898 ** at the b-tree/pager level.
899 */
900 void sqlite3CloseSavepoints(sqlite3 *db){
901   while( db->pSavepoint ){
902     Savepoint *pTmp = db->pSavepoint;
903     db->pSavepoint = pTmp->pNext;
904     sqlite3DbFree(db, pTmp);
905   }
906   db->nSavepoint = 0;
907   db->nStatement = 0;
908   db->isTransactionSavepoint = 0;
909 }
910 
911 /*
912 ** Invoke the destructor function associated with FuncDef p, if any. Except,
913 ** if this is not the last copy of the function, do not invoke it. Multiple
914 ** copies of a single function are created when create_function() is called
915 ** with SQLITE_ANY as the encoding.
916 */
917 static void functionDestroy(sqlite3 *db, FuncDef *p){
918   FuncDestructor *pDestructor = p->pDestructor;
919   if( pDestructor ){
920     pDestructor->nRef--;
921     if( pDestructor->nRef==0 ){
922       pDestructor->xDestroy(pDestructor->pUserData);
923       sqlite3DbFree(db, pDestructor);
924     }
925   }
926 }
927 
928 /*
929 ** Disconnect all sqlite3_vtab objects that belong to database connection
930 ** db. This is called when db is being closed.
931 */
932 static void disconnectAllVtab(sqlite3 *db){
933 #ifndef SQLITE_OMIT_VIRTUALTABLE
934   int i;
935   HashElem *p;
936   sqlite3BtreeEnterAll(db);
937   for(i=0; i<db->nDb; i++){
938     Schema *pSchema = db->aDb[i].pSchema;
939     if( db->aDb[i].pSchema ){
940       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
941         Table *pTab = (Table *)sqliteHashData(p);
942         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
943       }
944     }
945   }
946   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
947     Module *pMod = (Module *)sqliteHashData(p);
948     if( pMod->pEpoTab ){
949       sqlite3VtabDisconnect(db, pMod->pEpoTab);
950     }
951   }
952   sqlite3VtabUnlockList(db);
953   sqlite3BtreeLeaveAll(db);
954 #else
955   UNUSED_PARAMETER(db);
956 #endif
957 }
958 
959 /*
960 ** Return TRUE if database connection db has unfinalized prepared
961 ** statements or unfinished sqlite3_backup objects.
962 */
963 static int connectionIsBusy(sqlite3 *db){
964   int j;
965   assert( sqlite3_mutex_held(db->mutex) );
966   if( db->pVdbe ) return 1;
967   for(j=0; j<db->nDb; j++){
968     Btree *pBt = db->aDb[j].pBt;
969     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
970   }
971   return 0;
972 }
973 
974 /*
975 ** Close an existing SQLite database
976 */
977 static int sqlite3Close(sqlite3 *db, int forceZombie){
978   if( !db ){
979     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
980     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
981     return SQLITE_OK;
982   }
983   if( !sqlite3SafetyCheckSickOrOk(db) ){
984     return SQLITE_MISUSE_BKPT;
985   }
986   sqlite3_mutex_enter(db->mutex);
987 
988   /* Force xDisconnect calls on all virtual tables */
989   disconnectAllVtab(db);
990 
991   /* If a transaction is open, the disconnectAllVtab() call above
992   ** will not have called the xDisconnect() method on any virtual
993   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
994   ** call will do so. We need to do this before the check for active
995   ** SQL statements below, as the v-table implementation may be storing
996   ** some prepared statements internally.
997   */
998   sqlite3VtabRollback(db);
999 
1000   /* Legacy behavior (sqlite3_close() behavior) is to return
1001   ** SQLITE_BUSY if the connection can not be closed immediately.
1002   */
1003   if( !forceZombie && connectionIsBusy(db) ){
1004     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1005        "statements or unfinished backups");
1006     sqlite3_mutex_leave(db->mutex);
1007     return SQLITE_BUSY;
1008   }
1009 
1010 #ifdef SQLITE_ENABLE_SQLLOG
1011   if( sqlite3GlobalConfig.xSqllog ){
1012     /* Closing the handle. Fourth parameter is passed the value 2. */
1013     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1014   }
1015 #endif
1016 
1017   /* Convert the connection into a zombie and then close it.
1018   */
1019   db->magic = SQLITE_MAGIC_ZOMBIE;
1020   sqlite3LeaveMutexAndCloseZombie(db);
1021   return SQLITE_OK;
1022 }
1023 
1024 /*
1025 ** Two variations on the public interface for closing a database
1026 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1027 ** leaves the connection option if there are unfinalized prepared
1028 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1029 ** version forces the connection to become a zombie if there are
1030 ** unclosed resources, and arranges for deallocation when the last
1031 ** prepare statement or sqlite3_backup closes.
1032 */
1033 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1034 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1035 
1036 
1037 /*
1038 ** Close the mutex on database connection db.
1039 **
1040 ** Furthermore, if database connection db is a zombie (meaning that there
1041 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1042 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1043 ** finished, then free all resources.
1044 */
1045 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1046   HashElem *i;                    /* Hash table iterator */
1047   int j;
1048 
1049   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1050   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1051   ** then just leave the mutex and return.
1052   */
1053   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1054     sqlite3_mutex_leave(db->mutex);
1055     return;
1056   }
1057 
1058   /* If we reach this point, it means that the database connection has
1059   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1060   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1061   ** go ahead and free all resources.
1062   */
1063 
1064   /* If a transaction is open, roll it back. This also ensures that if
1065   ** any database schemas have been modified by an uncommitted transaction
1066   ** they are reset. And that the required b-tree mutex is held to make
1067   ** the pager rollback and schema reset an atomic operation. */
1068   sqlite3RollbackAll(db, SQLITE_OK);
1069 
1070   /* Free any outstanding Savepoint structures. */
1071   sqlite3CloseSavepoints(db);
1072 
1073   /* Close all database connections */
1074   for(j=0; j<db->nDb; j++){
1075     struct Db *pDb = &db->aDb[j];
1076     if( pDb->pBt ){
1077       sqlite3BtreeClose(pDb->pBt);
1078       pDb->pBt = 0;
1079       if( j!=1 ){
1080         pDb->pSchema = 0;
1081       }
1082     }
1083   }
1084   /* Clear the TEMP schema separately and last */
1085   if( db->aDb[1].pSchema ){
1086     sqlite3SchemaClear(db->aDb[1].pSchema);
1087   }
1088   sqlite3VtabUnlockList(db);
1089 
1090   /* Free up the array of auxiliary databases */
1091   sqlite3CollapseDatabaseArray(db);
1092   assert( db->nDb<=2 );
1093   assert( db->aDb==db->aDbStatic );
1094 
1095   /* Tell the code in notify.c that the connection no longer holds any
1096   ** locks and does not require any further unlock-notify callbacks.
1097   */
1098   sqlite3ConnectionClosed(db);
1099 
1100   for(j=0; j<ArraySize(db->aFunc.a); j++){
1101     FuncDef *pNext, *pHash, *p;
1102     for(p=db->aFunc.a[j]; p; p=pHash){
1103       pHash = p->pHash;
1104       while( p ){
1105         functionDestroy(db, p);
1106         pNext = p->pNext;
1107         sqlite3DbFree(db, p);
1108         p = pNext;
1109       }
1110     }
1111   }
1112   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1113     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1114     /* Invoke any destructors registered for collation sequence user data. */
1115     for(j=0; j<3; j++){
1116       if( pColl[j].xDel ){
1117         pColl[j].xDel(pColl[j].pUser);
1118       }
1119     }
1120     sqlite3DbFree(db, pColl);
1121   }
1122   sqlite3HashClear(&db->aCollSeq);
1123 #ifndef SQLITE_OMIT_VIRTUALTABLE
1124   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1125     Module *pMod = (Module *)sqliteHashData(i);
1126     if( pMod->xDestroy ){
1127       pMod->xDestroy(pMod->pAux);
1128     }
1129     sqlite3VtabEponymousTableClear(db, pMod);
1130     sqlite3DbFree(db, pMod);
1131   }
1132   sqlite3HashClear(&db->aModule);
1133 #endif
1134 
1135   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1136   sqlite3ValueFree(db->pErr);
1137   sqlite3CloseExtensions(db);
1138 #if SQLITE_USER_AUTHENTICATION
1139   sqlite3_free(db->auth.zAuthUser);
1140   sqlite3_free(db->auth.zAuthPW);
1141 #endif
1142 
1143   db->magic = SQLITE_MAGIC_ERROR;
1144 
1145   /* The temp-database schema is allocated differently from the other schema
1146   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1147   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1148   ** the same sqliteMalloc() as the one that allocates the database
1149   ** structure?
1150   */
1151   sqlite3DbFree(db, db->aDb[1].pSchema);
1152   sqlite3_mutex_leave(db->mutex);
1153   db->magic = SQLITE_MAGIC_CLOSED;
1154   sqlite3_mutex_free(db->mutex);
1155   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1156   if( db->lookaside.bMalloced ){
1157     sqlite3_free(db->lookaside.pStart);
1158   }
1159   sqlite3_free(db);
1160 }
1161 
1162 /*
1163 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1164 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1165 ** breaker") and made to return tripCode if there are any further
1166 ** attempts to use that cursor.  Read cursors remain open and valid
1167 ** but are "saved" in case the table pages are moved around.
1168 */
1169 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1170   int i;
1171   int inTrans = 0;
1172   int schemaChange;
1173   assert( sqlite3_mutex_held(db->mutex) );
1174   sqlite3BeginBenignMalloc();
1175 
1176   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1177   ** This is important in case the transaction being rolled back has
1178   ** modified the database schema. If the b-tree mutexes are not taken
1179   ** here, then another shared-cache connection might sneak in between
1180   ** the database rollback and schema reset, which can cause false
1181   ** corruption reports in some cases.  */
1182   sqlite3BtreeEnterAll(db);
1183   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1184 
1185   for(i=0; i<db->nDb; i++){
1186     Btree *p = db->aDb[i].pBt;
1187     if( p ){
1188       if( sqlite3BtreeIsInTrans(p) ){
1189         inTrans = 1;
1190       }
1191       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1192     }
1193   }
1194   sqlite3VtabRollback(db);
1195   sqlite3EndBenignMalloc();
1196 
1197   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1198     sqlite3ExpirePreparedStatements(db);
1199     sqlite3ResetAllSchemasOfConnection(db);
1200   }
1201   sqlite3BtreeLeaveAll(db);
1202 
1203   /* Any deferred constraint violations have now been resolved. */
1204   db->nDeferredCons = 0;
1205   db->nDeferredImmCons = 0;
1206   db->flags &= ~SQLITE_DeferFKs;
1207 
1208   /* If one has been configured, invoke the rollback-hook callback */
1209   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1210     db->xRollbackCallback(db->pRollbackArg);
1211   }
1212 }
1213 
1214 /*
1215 ** Return a static string containing the name corresponding to the error code
1216 ** specified in the argument.
1217 */
1218 #if defined(SQLITE_NEED_ERR_NAME)
1219 const char *sqlite3ErrName(int rc){
1220   const char *zName = 0;
1221   int i, origRc = rc;
1222   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1223     switch( rc ){
1224       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1225       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1226       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1227       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1228       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1229       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1230       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1231       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1232       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1233       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1234       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1235       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1236       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1237       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1238       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1239       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1240       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1241       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1242       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1243       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1244       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1245       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1246       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1247       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1248       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1249       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1250       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1251       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1252       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1253       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1254       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1255       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1256                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1257       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1258       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1259       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1260       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1261       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1262       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1263       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1264       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1265       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1266       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1267       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1268       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1269       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1270       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1271       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1272       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1273       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1274       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1275       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1276       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1277       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1278       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1279       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1280       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1281       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1282       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1283       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1284       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1285       case SQLITE_CONSTRAINT_FOREIGNKEY:
1286                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1287       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1288       case SQLITE_CONSTRAINT_PRIMARYKEY:
1289                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1290       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1291       case SQLITE_CONSTRAINT_COMMITHOOK:
1292                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1293       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1294       case SQLITE_CONSTRAINT_FUNCTION:
1295                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1296       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1297       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1298       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1299       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1300       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1301       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1302       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1303       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1304       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1305       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1306       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1307       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1308                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1309       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1310       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1311       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1312     }
1313   }
1314   if( zName==0 ){
1315     static char zBuf[50];
1316     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1317     zName = zBuf;
1318   }
1319   return zName;
1320 }
1321 #endif
1322 
1323 /*
1324 ** Return a static string that describes the kind of error specified in the
1325 ** argument.
1326 */
1327 const char *sqlite3ErrStr(int rc){
1328   static const char* const aMsg[] = {
1329     /* SQLITE_OK          */ "not an error",
1330     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1331     /* SQLITE_INTERNAL    */ 0,
1332     /* SQLITE_PERM        */ "access permission denied",
1333     /* SQLITE_ABORT       */ "callback requested query abort",
1334     /* SQLITE_BUSY        */ "database is locked",
1335     /* SQLITE_LOCKED      */ "database table is locked",
1336     /* SQLITE_NOMEM       */ "out of memory",
1337     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1338     /* SQLITE_INTERRUPT   */ "interrupted",
1339     /* SQLITE_IOERR       */ "disk I/O error",
1340     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1341     /* SQLITE_NOTFOUND    */ "unknown operation",
1342     /* SQLITE_FULL        */ "database or disk is full",
1343     /* SQLITE_CANTOPEN    */ "unable to open database file",
1344     /* SQLITE_PROTOCOL    */ "locking protocol",
1345     /* SQLITE_EMPTY       */ "table contains no data",
1346     /* SQLITE_SCHEMA      */ "database schema has changed",
1347     /* SQLITE_TOOBIG      */ "string or blob too big",
1348     /* SQLITE_CONSTRAINT  */ "constraint failed",
1349     /* SQLITE_MISMATCH    */ "datatype mismatch",
1350     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1351     /* SQLITE_NOLFS       */ "large file support is disabled",
1352     /* SQLITE_AUTH        */ "authorization denied",
1353     /* SQLITE_FORMAT      */ "auxiliary database format error",
1354     /* SQLITE_RANGE       */ "bind or column index out of range",
1355     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1356   };
1357   const char *zErr = "unknown error";
1358   switch( rc ){
1359     case SQLITE_ABORT_ROLLBACK: {
1360       zErr = "abort due to ROLLBACK";
1361       break;
1362     }
1363     default: {
1364       rc &= 0xff;
1365       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1366         zErr = aMsg[rc];
1367       }
1368       break;
1369     }
1370   }
1371   return zErr;
1372 }
1373 
1374 /*
1375 ** This routine implements a busy callback that sleeps and tries
1376 ** again until a timeout value is reached.  The timeout value is
1377 ** an integer number of milliseconds passed in as the first
1378 ** argument.
1379 */
1380 static int sqliteDefaultBusyCallback(
1381  void *ptr,               /* Database connection */
1382  int count                /* Number of times table has been busy */
1383 ){
1384 #if SQLITE_OS_WIN || HAVE_USLEEP
1385   static const u8 delays[] =
1386      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1387   static const u8 totals[] =
1388      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1389 # define NDELAY ArraySize(delays)
1390   sqlite3 *db = (sqlite3 *)ptr;
1391   int timeout = db->busyTimeout;
1392   int delay, prior;
1393 
1394   assert( count>=0 );
1395   if( count < NDELAY ){
1396     delay = delays[count];
1397     prior = totals[count];
1398   }else{
1399     delay = delays[NDELAY-1];
1400     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1401   }
1402   if( prior + delay > timeout ){
1403     delay = timeout - prior;
1404     if( delay<=0 ) return 0;
1405   }
1406   sqlite3OsSleep(db->pVfs, delay*1000);
1407   return 1;
1408 #else
1409   sqlite3 *db = (sqlite3 *)ptr;
1410   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1411   if( (count+1)*1000 > timeout ){
1412     return 0;
1413   }
1414   sqlite3OsSleep(db->pVfs, 1000000);
1415   return 1;
1416 #endif
1417 }
1418 
1419 /*
1420 ** Invoke the given busy handler.
1421 **
1422 ** This routine is called when an operation failed with a lock.
1423 ** If this routine returns non-zero, the lock is retried.  If it
1424 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1425 */
1426 int sqlite3InvokeBusyHandler(BusyHandler *p){
1427   int rc;
1428   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1429   rc = p->xFunc(p->pArg, p->nBusy);
1430   if( rc==0 ){
1431     p->nBusy = -1;
1432   }else{
1433     p->nBusy++;
1434   }
1435   return rc;
1436 }
1437 
1438 /*
1439 ** This routine sets the busy callback for an Sqlite database to the
1440 ** given callback function with the given argument.
1441 */
1442 int sqlite3_busy_handler(
1443   sqlite3 *db,
1444   int (*xBusy)(void*,int),
1445   void *pArg
1446 ){
1447 #ifdef SQLITE_ENABLE_API_ARMOR
1448   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1449 #endif
1450   sqlite3_mutex_enter(db->mutex);
1451   db->busyHandler.xFunc = xBusy;
1452   db->busyHandler.pArg = pArg;
1453   db->busyHandler.nBusy = 0;
1454   db->busyTimeout = 0;
1455   sqlite3_mutex_leave(db->mutex);
1456   return SQLITE_OK;
1457 }
1458 
1459 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1460 /*
1461 ** This routine sets the progress callback for an Sqlite database to the
1462 ** given callback function with the given argument. The progress callback will
1463 ** be invoked every nOps opcodes.
1464 */
1465 void sqlite3_progress_handler(
1466   sqlite3 *db,
1467   int nOps,
1468   int (*xProgress)(void*),
1469   void *pArg
1470 ){
1471 #ifdef SQLITE_ENABLE_API_ARMOR
1472   if( !sqlite3SafetyCheckOk(db) ){
1473     (void)SQLITE_MISUSE_BKPT;
1474     return;
1475   }
1476 #endif
1477   sqlite3_mutex_enter(db->mutex);
1478   if( nOps>0 ){
1479     db->xProgress = xProgress;
1480     db->nProgressOps = (unsigned)nOps;
1481     db->pProgressArg = pArg;
1482   }else{
1483     db->xProgress = 0;
1484     db->nProgressOps = 0;
1485     db->pProgressArg = 0;
1486   }
1487   sqlite3_mutex_leave(db->mutex);
1488 }
1489 #endif
1490 
1491 
1492 /*
1493 ** This routine installs a default busy handler that waits for the
1494 ** specified number of milliseconds before returning 0.
1495 */
1496 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1497 #ifdef SQLITE_ENABLE_API_ARMOR
1498   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1499 #endif
1500   if( ms>0 ){
1501     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1502     db->busyTimeout = ms;
1503   }else{
1504     sqlite3_busy_handler(db, 0, 0);
1505   }
1506   return SQLITE_OK;
1507 }
1508 
1509 /*
1510 ** Cause any pending operation to stop at its earliest opportunity.
1511 */
1512 void sqlite3_interrupt(sqlite3 *db){
1513 #ifdef SQLITE_ENABLE_API_ARMOR
1514   if( !sqlite3SafetyCheckOk(db) ){
1515     (void)SQLITE_MISUSE_BKPT;
1516     return;
1517   }
1518 #endif
1519   db->u1.isInterrupted = 1;
1520 }
1521 
1522 
1523 /*
1524 ** This function is exactly the same as sqlite3_create_function(), except
1525 ** that it is designed to be called by internal code. The difference is
1526 ** that if a malloc() fails in sqlite3_create_function(), an error code
1527 ** is returned and the mallocFailed flag cleared.
1528 */
1529 int sqlite3CreateFunc(
1530   sqlite3 *db,
1531   const char *zFunctionName,
1532   int nArg,
1533   int enc,
1534   void *pUserData,
1535   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1536   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1537   void (*xFinal)(sqlite3_context*),
1538   FuncDestructor *pDestructor
1539 ){
1540   FuncDef *p;
1541   int nName;
1542   int extraFlags;
1543 
1544   assert( sqlite3_mutex_held(db->mutex) );
1545   if( zFunctionName==0 ||
1546       (xFunc && (xFinal || xStep)) ||
1547       (!xFunc && (xFinal && !xStep)) ||
1548       (!xFunc && (!xFinal && xStep)) ||
1549       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1550       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1551     return SQLITE_MISUSE_BKPT;
1552   }
1553 
1554   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1555   extraFlags = enc &  SQLITE_DETERMINISTIC;
1556   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1557 
1558 #ifndef SQLITE_OMIT_UTF16
1559   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1560   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1561   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1562   **
1563   ** If SQLITE_ANY is specified, add three versions of the function
1564   ** to the hash table.
1565   */
1566   if( enc==SQLITE_UTF16 ){
1567     enc = SQLITE_UTF16NATIVE;
1568   }else if( enc==SQLITE_ANY ){
1569     int rc;
1570     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1571          pUserData, xFunc, xStep, xFinal, pDestructor);
1572     if( rc==SQLITE_OK ){
1573       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1574           pUserData, xFunc, xStep, xFinal, pDestructor);
1575     }
1576     if( rc!=SQLITE_OK ){
1577       return rc;
1578     }
1579     enc = SQLITE_UTF16BE;
1580   }
1581 #else
1582   enc = SQLITE_UTF8;
1583 #endif
1584 
1585   /* Check if an existing function is being overridden or deleted. If so,
1586   ** and there are active VMs, then return SQLITE_BUSY. If a function
1587   ** is being overridden/deleted but there are no active VMs, allow the
1588   ** operation to continue but invalidate all precompiled statements.
1589   */
1590   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1591   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1592     if( db->nVdbeActive ){
1593       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1594         "unable to delete/modify user-function due to active statements");
1595       assert( !db->mallocFailed );
1596       return SQLITE_BUSY;
1597     }else{
1598       sqlite3ExpirePreparedStatements(db);
1599     }
1600   }
1601 
1602   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1603   assert(p || db->mallocFailed);
1604   if( !p ){
1605     return SQLITE_NOMEM;
1606   }
1607 
1608   /* If an older version of the function with a configured destructor is
1609   ** being replaced invoke the destructor function here. */
1610   functionDestroy(db, p);
1611 
1612   if( pDestructor ){
1613     pDestructor->nRef++;
1614   }
1615   p->pDestructor = pDestructor;
1616   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1617   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1618   p->xFunc = xFunc;
1619   p->xStep = xStep;
1620   p->xFinalize = xFinal;
1621   p->pUserData = pUserData;
1622   p->nArg = (u16)nArg;
1623   return SQLITE_OK;
1624 }
1625 
1626 /*
1627 ** Create new user functions.
1628 */
1629 int sqlite3_create_function(
1630   sqlite3 *db,
1631   const char *zFunc,
1632   int nArg,
1633   int enc,
1634   void *p,
1635   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1636   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1637   void (*xFinal)(sqlite3_context*)
1638 ){
1639   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
1640                                     xFinal, 0);
1641 }
1642 
1643 int sqlite3_create_function_v2(
1644   sqlite3 *db,
1645   const char *zFunc,
1646   int nArg,
1647   int enc,
1648   void *p,
1649   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1650   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1651   void (*xFinal)(sqlite3_context*),
1652   void (*xDestroy)(void *)
1653 ){
1654   int rc = SQLITE_ERROR;
1655   FuncDestructor *pArg = 0;
1656 
1657 #ifdef SQLITE_ENABLE_API_ARMOR
1658   if( !sqlite3SafetyCheckOk(db) ){
1659     return SQLITE_MISUSE_BKPT;
1660   }
1661 #endif
1662   sqlite3_mutex_enter(db->mutex);
1663   if( xDestroy ){
1664     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1665     if( !pArg ){
1666       xDestroy(p);
1667       goto out;
1668     }
1669     pArg->xDestroy = xDestroy;
1670     pArg->pUserData = p;
1671   }
1672   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
1673   if( pArg && pArg->nRef==0 ){
1674     assert( rc!=SQLITE_OK );
1675     xDestroy(p);
1676     sqlite3DbFree(db, pArg);
1677   }
1678 
1679  out:
1680   rc = sqlite3ApiExit(db, rc);
1681   sqlite3_mutex_leave(db->mutex);
1682   return rc;
1683 }
1684 
1685 #ifndef SQLITE_OMIT_UTF16
1686 int sqlite3_create_function16(
1687   sqlite3 *db,
1688   const void *zFunctionName,
1689   int nArg,
1690   int eTextRep,
1691   void *p,
1692   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1693   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1694   void (*xFinal)(sqlite3_context*)
1695 ){
1696   int rc;
1697   char *zFunc8;
1698 
1699 #ifdef SQLITE_ENABLE_API_ARMOR
1700   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1701 #endif
1702   sqlite3_mutex_enter(db->mutex);
1703   assert( !db->mallocFailed );
1704   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1705   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
1706   sqlite3DbFree(db, zFunc8);
1707   rc = sqlite3ApiExit(db, rc);
1708   sqlite3_mutex_leave(db->mutex);
1709   return rc;
1710 }
1711 #endif
1712 
1713 
1714 /*
1715 ** Declare that a function has been overloaded by a virtual table.
1716 **
1717 ** If the function already exists as a regular global function, then
1718 ** this routine is a no-op.  If the function does not exist, then create
1719 ** a new one that always throws a run-time error.
1720 **
1721 ** When virtual tables intend to provide an overloaded function, they
1722 ** should call this routine to make sure the global function exists.
1723 ** A global function must exist in order for name resolution to work
1724 ** properly.
1725 */
1726 int sqlite3_overload_function(
1727   sqlite3 *db,
1728   const char *zName,
1729   int nArg
1730 ){
1731   int nName = sqlite3Strlen30(zName);
1732   int rc = SQLITE_OK;
1733 
1734 #ifdef SQLITE_ENABLE_API_ARMOR
1735   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1736     return SQLITE_MISUSE_BKPT;
1737   }
1738 #endif
1739   sqlite3_mutex_enter(db->mutex);
1740   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1741     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1742                            0, sqlite3InvalidFunction, 0, 0, 0);
1743   }
1744   rc = sqlite3ApiExit(db, rc);
1745   sqlite3_mutex_leave(db->mutex);
1746   return rc;
1747 }
1748 
1749 #ifndef SQLITE_OMIT_TRACE
1750 /*
1751 ** Register a trace function.  The pArg from the previously registered trace
1752 ** is returned.
1753 **
1754 ** A NULL trace function means that no tracing is executes.  A non-NULL
1755 ** trace is a pointer to a function that is invoked at the start of each
1756 ** SQL statement.
1757 */
1758 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1759   void *pOld;
1760 
1761 #ifdef SQLITE_ENABLE_API_ARMOR
1762   if( !sqlite3SafetyCheckOk(db) ){
1763     (void)SQLITE_MISUSE_BKPT;
1764     return 0;
1765   }
1766 #endif
1767   sqlite3_mutex_enter(db->mutex);
1768   pOld = db->pTraceArg;
1769   db->xTrace = xTrace;
1770   db->pTraceArg = pArg;
1771   sqlite3_mutex_leave(db->mutex);
1772   return pOld;
1773 }
1774 /*
1775 ** Register a profile function.  The pArg from the previously registered
1776 ** profile function is returned.
1777 **
1778 ** A NULL profile function means that no profiling is executes.  A non-NULL
1779 ** profile is a pointer to a function that is invoked at the conclusion of
1780 ** each SQL statement that is run.
1781 */
1782 void *sqlite3_profile(
1783   sqlite3 *db,
1784   void (*xProfile)(void*,const char*,sqlite_uint64),
1785   void *pArg
1786 ){
1787   void *pOld;
1788 
1789 #ifdef SQLITE_ENABLE_API_ARMOR
1790   if( !sqlite3SafetyCheckOk(db) ){
1791     (void)SQLITE_MISUSE_BKPT;
1792     return 0;
1793   }
1794 #endif
1795   sqlite3_mutex_enter(db->mutex);
1796   pOld = db->pProfileArg;
1797   db->xProfile = xProfile;
1798   db->pProfileArg = pArg;
1799   sqlite3_mutex_leave(db->mutex);
1800   return pOld;
1801 }
1802 #endif /* SQLITE_OMIT_TRACE */
1803 
1804 /*
1805 ** Register a function to be invoked when a transaction commits.
1806 ** If the invoked function returns non-zero, then the commit becomes a
1807 ** rollback.
1808 */
1809 void *sqlite3_commit_hook(
1810   sqlite3 *db,              /* Attach the hook to this database */
1811   int (*xCallback)(void*),  /* Function to invoke on each commit */
1812   void *pArg                /* Argument to the function */
1813 ){
1814   void *pOld;
1815 
1816 #ifdef SQLITE_ENABLE_API_ARMOR
1817   if( !sqlite3SafetyCheckOk(db) ){
1818     (void)SQLITE_MISUSE_BKPT;
1819     return 0;
1820   }
1821 #endif
1822   sqlite3_mutex_enter(db->mutex);
1823   pOld = db->pCommitArg;
1824   db->xCommitCallback = xCallback;
1825   db->pCommitArg = pArg;
1826   sqlite3_mutex_leave(db->mutex);
1827   return pOld;
1828 }
1829 
1830 /*
1831 ** Register a callback to be invoked each time a row is updated,
1832 ** inserted or deleted using this database connection.
1833 */
1834 void *sqlite3_update_hook(
1835   sqlite3 *db,              /* Attach the hook to this database */
1836   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1837   void *pArg                /* Argument to the function */
1838 ){
1839   void *pRet;
1840 
1841 #ifdef SQLITE_ENABLE_API_ARMOR
1842   if( !sqlite3SafetyCheckOk(db) ){
1843     (void)SQLITE_MISUSE_BKPT;
1844     return 0;
1845   }
1846 #endif
1847   sqlite3_mutex_enter(db->mutex);
1848   pRet = db->pUpdateArg;
1849   db->xUpdateCallback = xCallback;
1850   db->pUpdateArg = pArg;
1851   sqlite3_mutex_leave(db->mutex);
1852   return pRet;
1853 }
1854 
1855 /*
1856 ** Register a callback to be invoked each time a transaction is rolled
1857 ** back by this database connection.
1858 */
1859 void *sqlite3_rollback_hook(
1860   sqlite3 *db,              /* Attach the hook to this database */
1861   void (*xCallback)(void*), /* Callback function */
1862   void *pArg                /* Argument to the function */
1863 ){
1864   void *pRet;
1865 
1866 #ifdef SQLITE_ENABLE_API_ARMOR
1867   if( !sqlite3SafetyCheckOk(db) ){
1868     (void)SQLITE_MISUSE_BKPT;
1869     return 0;
1870   }
1871 #endif
1872   sqlite3_mutex_enter(db->mutex);
1873   pRet = db->pRollbackArg;
1874   db->xRollbackCallback = xCallback;
1875   db->pRollbackArg = pArg;
1876   sqlite3_mutex_leave(db->mutex);
1877   return pRet;
1878 }
1879 
1880 #ifndef SQLITE_OMIT_WAL
1881 /*
1882 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1883 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1884 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1885 ** wal_autocheckpoint()).
1886 */
1887 int sqlite3WalDefaultHook(
1888   void *pClientData,     /* Argument */
1889   sqlite3 *db,           /* Connection */
1890   const char *zDb,       /* Database */
1891   int nFrame             /* Size of WAL */
1892 ){
1893   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1894     sqlite3BeginBenignMalloc();
1895     sqlite3_wal_checkpoint(db, zDb);
1896     sqlite3EndBenignMalloc();
1897   }
1898   return SQLITE_OK;
1899 }
1900 #endif /* SQLITE_OMIT_WAL */
1901 
1902 /*
1903 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1904 ** a database after committing a transaction if there are nFrame or
1905 ** more frames in the log file. Passing zero or a negative value as the
1906 ** nFrame parameter disables automatic checkpoints entirely.
1907 **
1908 ** The callback registered by this function replaces any existing callback
1909 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1910 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1911 ** configured by this function.
1912 */
1913 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1914 #ifdef SQLITE_OMIT_WAL
1915   UNUSED_PARAMETER(db);
1916   UNUSED_PARAMETER(nFrame);
1917 #else
1918 #ifdef SQLITE_ENABLE_API_ARMOR
1919   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1920 #endif
1921   if( nFrame>0 ){
1922     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1923   }else{
1924     sqlite3_wal_hook(db, 0, 0);
1925   }
1926 #endif
1927   return SQLITE_OK;
1928 }
1929 
1930 /*
1931 ** Register a callback to be invoked each time a transaction is written
1932 ** into the write-ahead-log by this database connection.
1933 */
1934 void *sqlite3_wal_hook(
1935   sqlite3 *db,                    /* Attach the hook to this db handle */
1936   int(*xCallback)(void *, sqlite3*, const char*, int),
1937   void *pArg                      /* First argument passed to xCallback() */
1938 ){
1939 #ifndef SQLITE_OMIT_WAL
1940   void *pRet;
1941 #ifdef SQLITE_ENABLE_API_ARMOR
1942   if( !sqlite3SafetyCheckOk(db) ){
1943     (void)SQLITE_MISUSE_BKPT;
1944     return 0;
1945   }
1946 #endif
1947   sqlite3_mutex_enter(db->mutex);
1948   pRet = db->pWalArg;
1949   db->xWalCallback = xCallback;
1950   db->pWalArg = pArg;
1951   sqlite3_mutex_leave(db->mutex);
1952   return pRet;
1953 #else
1954   return 0;
1955 #endif
1956 }
1957 
1958 /*
1959 ** Checkpoint database zDb.
1960 */
1961 int sqlite3_wal_checkpoint_v2(
1962   sqlite3 *db,                    /* Database handle */
1963   const char *zDb,                /* Name of attached database (or NULL) */
1964   int eMode,                      /* SQLITE_CHECKPOINT_* value */
1965   int *pnLog,                     /* OUT: Size of WAL log in frames */
1966   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
1967 ){
1968 #ifdef SQLITE_OMIT_WAL
1969   return SQLITE_OK;
1970 #else
1971   int rc;                         /* Return code */
1972   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
1973 
1974 #ifdef SQLITE_ENABLE_API_ARMOR
1975   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1976 #endif
1977 
1978   /* Initialize the output variables to -1 in case an error occurs. */
1979   if( pnLog ) *pnLog = -1;
1980   if( pnCkpt ) *pnCkpt = -1;
1981 
1982   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
1983   assert( SQLITE_CHECKPOINT_FULL==1 );
1984   assert( SQLITE_CHECKPOINT_RESTART==2 );
1985   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
1986   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
1987     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
1988     ** mode: */
1989     return SQLITE_MISUSE;
1990   }
1991 
1992   sqlite3_mutex_enter(db->mutex);
1993   if( zDb && zDb[0] ){
1994     iDb = sqlite3FindDbName(db, zDb);
1995   }
1996   if( iDb<0 ){
1997     rc = SQLITE_ERROR;
1998     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
1999   }else{
2000     db->busyHandler.nBusy = 0;
2001     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2002     sqlite3Error(db, rc);
2003   }
2004   rc = sqlite3ApiExit(db, rc);
2005   sqlite3_mutex_leave(db->mutex);
2006   return rc;
2007 #endif
2008 }
2009 
2010 
2011 /*
2012 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2013 ** to contains a zero-length string, all attached databases are
2014 ** checkpointed.
2015 */
2016 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2017   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2018   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2019   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2020 }
2021 
2022 #ifndef SQLITE_OMIT_WAL
2023 /*
2024 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2025 ** not currently open in WAL mode.
2026 **
2027 ** If a transaction is open on the database being checkpointed, this
2028 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2029 ** an error occurs while running the checkpoint, an SQLite error code is
2030 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2031 **
2032 ** The mutex on database handle db should be held by the caller. The mutex
2033 ** associated with the specific b-tree being checkpointed is taken by
2034 ** this function while the checkpoint is running.
2035 **
2036 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2037 ** checkpointed. If an error is encountered it is returned immediately -
2038 ** no attempt is made to checkpoint any remaining databases.
2039 **
2040 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2041 */
2042 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2043   int rc = SQLITE_OK;             /* Return code */
2044   int i;                          /* Used to iterate through attached dbs */
2045   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2046 
2047   assert( sqlite3_mutex_held(db->mutex) );
2048   assert( !pnLog || *pnLog==-1 );
2049   assert( !pnCkpt || *pnCkpt==-1 );
2050 
2051   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2052     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2053       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2054       pnLog = 0;
2055       pnCkpt = 0;
2056       if( rc==SQLITE_BUSY ){
2057         bBusy = 1;
2058         rc = SQLITE_OK;
2059       }
2060     }
2061   }
2062 
2063   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2064 }
2065 #endif /* SQLITE_OMIT_WAL */
2066 
2067 /*
2068 ** This function returns true if main-memory should be used instead of
2069 ** a temporary file for transient pager files and statement journals.
2070 ** The value returned depends on the value of db->temp_store (runtime
2071 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2072 ** following table describes the relationship between these two values
2073 ** and this functions return value.
2074 **
2075 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2076 **   -----------------     --------------     ------------------------------
2077 **   0                     any                file      (return 0)
2078 **   1                     1                  file      (return 0)
2079 **   1                     2                  memory    (return 1)
2080 **   1                     0                  file      (return 0)
2081 **   2                     1                  file      (return 0)
2082 **   2                     2                  memory    (return 1)
2083 **   2                     0                  memory    (return 1)
2084 **   3                     any                memory    (return 1)
2085 */
2086 int sqlite3TempInMemory(const sqlite3 *db){
2087 #if SQLITE_TEMP_STORE==1
2088   return ( db->temp_store==2 );
2089 #endif
2090 #if SQLITE_TEMP_STORE==2
2091   return ( db->temp_store!=1 );
2092 #endif
2093 #if SQLITE_TEMP_STORE==3
2094   UNUSED_PARAMETER(db);
2095   return 1;
2096 #endif
2097 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2098   UNUSED_PARAMETER(db);
2099   return 0;
2100 #endif
2101 }
2102 
2103 /*
2104 ** Return UTF-8 encoded English language explanation of the most recent
2105 ** error.
2106 */
2107 const char *sqlite3_errmsg(sqlite3 *db){
2108   const char *z;
2109   if( !db ){
2110     return sqlite3ErrStr(SQLITE_NOMEM);
2111   }
2112   if( !sqlite3SafetyCheckSickOrOk(db) ){
2113     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2114   }
2115   sqlite3_mutex_enter(db->mutex);
2116   if( db->mallocFailed ){
2117     z = sqlite3ErrStr(SQLITE_NOMEM);
2118   }else{
2119     testcase( db->pErr==0 );
2120     z = (char*)sqlite3_value_text(db->pErr);
2121     assert( !db->mallocFailed );
2122     if( z==0 ){
2123       z = sqlite3ErrStr(db->errCode);
2124     }
2125   }
2126   sqlite3_mutex_leave(db->mutex);
2127   return z;
2128 }
2129 
2130 #ifndef SQLITE_OMIT_UTF16
2131 /*
2132 ** Return UTF-16 encoded English language explanation of the most recent
2133 ** error.
2134 */
2135 const void *sqlite3_errmsg16(sqlite3 *db){
2136   static const u16 outOfMem[] = {
2137     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2138   };
2139   static const u16 misuse[] = {
2140     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2141     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2142     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2143     'o', 'u', 't', ' ',
2144     'o', 'f', ' ',
2145     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2146   };
2147 
2148   const void *z;
2149   if( !db ){
2150     return (void *)outOfMem;
2151   }
2152   if( !sqlite3SafetyCheckSickOrOk(db) ){
2153     return (void *)misuse;
2154   }
2155   sqlite3_mutex_enter(db->mutex);
2156   if( db->mallocFailed ){
2157     z = (void *)outOfMem;
2158   }else{
2159     z = sqlite3_value_text16(db->pErr);
2160     if( z==0 ){
2161       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2162       z = sqlite3_value_text16(db->pErr);
2163     }
2164     /* A malloc() may have failed within the call to sqlite3_value_text16()
2165     ** above. If this is the case, then the db->mallocFailed flag needs to
2166     ** be cleared before returning. Do this directly, instead of via
2167     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2168     */
2169     db->mallocFailed = 0;
2170   }
2171   sqlite3_mutex_leave(db->mutex);
2172   return z;
2173 }
2174 #endif /* SQLITE_OMIT_UTF16 */
2175 
2176 /*
2177 ** Return the most recent error code generated by an SQLite routine. If NULL is
2178 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2179 */
2180 int sqlite3_errcode(sqlite3 *db){
2181   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2182     return SQLITE_MISUSE_BKPT;
2183   }
2184   if( !db || db->mallocFailed ){
2185     return SQLITE_NOMEM;
2186   }
2187   return db->errCode & db->errMask;
2188 }
2189 int sqlite3_extended_errcode(sqlite3 *db){
2190   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2191     return SQLITE_MISUSE_BKPT;
2192   }
2193   if( !db || db->mallocFailed ){
2194     return SQLITE_NOMEM;
2195   }
2196   return db->errCode;
2197 }
2198 
2199 /*
2200 ** Return a string that describes the kind of error specified in the
2201 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2202 ** function.
2203 */
2204 const char *sqlite3_errstr(int rc){
2205   return sqlite3ErrStr(rc);
2206 }
2207 
2208 /*
2209 ** Create a new collating function for database "db".  The name is zName
2210 ** and the encoding is enc.
2211 */
2212 static int createCollation(
2213   sqlite3* db,
2214   const char *zName,
2215   u8 enc,
2216   void* pCtx,
2217   int(*xCompare)(void*,int,const void*,int,const void*),
2218   void(*xDel)(void*)
2219 ){
2220   CollSeq *pColl;
2221   int enc2;
2222 
2223   assert( sqlite3_mutex_held(db->mutex) );
2224 
2225   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2226   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2227   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2228   */
2229   enc2 = enc;
2230   testcase( enc2==SQLITE_UTF16 );
2231   testcase( enc2==SQLITE_UTF16_ALIGNED );
2232   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2233     enc2 = SQLITE_UTF16NATIVE;
2234   }
2235   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2236     return SQLITE_MISUSE_BKPT;
2237   }
2238 
2239   /* Check if this call is removing or replacing an existing collation
2240   ** sequence. If so, and there are active VMs, return busy. If there
2241   ** are no active VMs, invalidate any pre-compiled statements.
2242   */
2243   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2244   if( pColl && pColl->xCmp ){
2245     if( db->nVdbeActive ){
2246       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2247         "unable to delete/modify collation sequence due to active statements");
2248       return SQLITE_BUSY;
2249     }
2250     sqlite3ExpirePreparedStatements(db);
2251 
2252     /* If collation sequence pColl was created directly by a call to
2253     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2254     ** then any copies made by synthCollSeq() need to be invalidated.
2255     ** Also, collation destructor - CollSeq.xDel() - function may need
2256     ** to be called.
2257     */
2258     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2259       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2260       int j;
2261       for(j=0; j<3; j++){
2262         CollSeq *p = &aColl[j];
2263         if( p->enc==pColl->enc ){
2264           if( p->xDel ){
2265             p->xDel(p->pUser);
2266           }
2267           p->xCmp = 0;
2268         }
2269       }
2270     }
2271   }
2272 
2273   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2274   if( pColl==0 ) return SQLITE_NOMEM;
2275   pColl->xCmp = xCompare;
2276   pColl->pUser = pCtx;
2277   pColl->xDel = xDel;
2278   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2279   sqlite3Error(db, SQLITE_OK);
2280   return SQLITE_OK;
2281 }
2282 
2283 
2284 /*
2285 ** This array defines hard upper bounds on limit values.  The
2286 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2287 ** #defines in sqlite3.h.
2288 */
2289 static const int aHardLimit[] = {
2290   SQLITE_MAX_LENGTH,
2291   SQLITE_MAX_SQL_LENGTH,
2292   SQLITE_MAX_COLUMN,
2293   SQLITE_MAX_EXPR_DEPTH,
2294   SQLITE_MAX_COMPOUND_SELECT,
2295   SQLITE_MAX_VDBE_OP,
2296   SQLITE_MAX_FUNCTION_ARG,
2297   SQLITE_MAX_ATTACHED,
2298   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2299   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2300   SQLITE_MAX_TRIGGER_DEPTH,
2301   SQLITE_MAX_WORKER_THREADS,
2302 };
2303 
2304 /*
2305 ** Make sure the hard limits are set to reasonable values
2306 */
2307 #if SQLITE_MAX_LENGTH<100
2308 # error SQLITE_MAX_LENGTH must be at least 100
2309 #endif
2310 #if SQLITE_MAX_SQL_LENGTH<100
2311 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2312 #endif
2313 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2314 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2315 #endif
2316 #if SQLITE_MAX_COMPOUND_SELECT<2
2317 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2318 #endif
2319 #if SQLITE_MAX_VDBE_OP<40
2320 # error SQLITE_MAX_VDBE_OP must be at least 40
2321 #endif
2322 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2323 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2324 #endif
2325 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2326 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2327 #endif
2328 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2329 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2330 #endif
2331 #if SQLITE_MAX_COLUMN>32767
2332 # error SQLITE_MAX_COLUMN must not exceed 32767
2333 #endif
2334 #if SQLITE_MAX_TRIGGER_DEPTH<1
2335 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2336 #endif
2337 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2338 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2339 #endif
2340 
2341 
2342 /*
2343 ** Change the value of a limit.  Report the old value.
2344 ** If an invalid limit index is supplied, report -1.
2345 ** Make no changes but still report the old value if the
2346 ** new limit is negative.
2347 **
2348 ** A new lower limit does not shrink existing constructs.
2349 ** It merely prevents new constructs that exceed the limit
2350 ** from forming.
2351 */
2352 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2353   int oldLimit;
2354 
2355 #ifdef SQLITE_ENABLE_API_ARMOR
2356   if( !sqlite3SafetyCheckOk(db) ){
2357     (void)SQLITE_MISUSE_BKPT;
2358     return -1;
2359   }
2360 #endif
2361 
2362   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2363   ** there is a hard upper bound set at compile-time by a C preprocessor
2364   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2365   ** "_MAX_".)
2366   */
2367   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2368   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2369   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2370   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2371   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2372   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2373   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2374   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2375   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2376                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2377   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2378   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2379   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2380   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2381 
2382 
2383   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2384     return -1;
2385   }
2386   oldLimit = db->aLimit[limitId];
2387   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2388     if( newLimit>aHardLimit[limitId] ){
2389       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2390     }
2391     db->aLimit[limitId] = newLimit;
2392   }
2393   return oldLimit;                     /* IMP: R-53341-35419 */
2394 }
2395 
2396 /*
2397 ** This function is used to parse both URIs and non-URI filenames passed by the
2398 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2399 ** URIs specified as part of ATTACH statements.
2400 **
2401 ** The first argument to this function is the name of the VFS to use (or
2402 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2403 ** query parameter. The second argument contains the URI (or non-URI filename)
2404 ** itself. When this function is called the *pFlags variable should contain
2405 ** the default flags to open the database handle with. The value stored in
2406 ** *pFlags may be updated before returning if the URI filename contains
2407 ** "cache=xxx" or "mode=xxx" query parameters.
2408 **
2409 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2410 ** the VFS that should be used to open the database file. *pzFile is set to
2411 ** point to a buffer containing the name of the file to open. It is the
2412 ** responsibility of the caller to eventually call sqlite3_free() to release
2413 ** this buffer.
2414 **
2415 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2416 ** may be set to point to a buffer containing an English language error
2417 ** message. It is the responsibility of the caller to eventually release
2418 ** this buffer by calling sqlite3_free().
2419 */
2420 int sqlite3ParseUri(
2421   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2422   const char *zUri,               /* Nul-terminated URI to parse */
2423   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2424   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2425   char **pzFile,                  /* OUT: Filename component of URI */
2426   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2427 ){
2428   int rc = SQLITE_OK;
2429   unsigned int flags = *pFlags;
2430   const char *zVfs = zDefaultVfs;
2431   char *zFile;
2432   char c;
2433   int nUri = sqlite3Strlen30(zUri);
2434 
2435   assert( *pzErrMsg==0 );
2436 
2437   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2438             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2439    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2440   ){
2441     char *zOpt;
2442     int eState;                   /* Parser state when parsing URI */
2443     int iIn;                      /* Input character index */
2444     int iOut = 0;                 /* Output character index */
2445     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2446 
2447     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2448     ** method that there may be extra parameters following the file-name.  */
2449     flags |= SQLITE_OPEN_URI;
2450 
2451     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2452     zFile = sqlite3_malloc64(nByte);
2453     if( !zFile ) return SQLITE_NOMEM;
2454 
2455     iIn = 5;
2456 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2457     if( strncmp(zUri+5, "///", 3)==0 ){
2458       iIn = 7;
2459       /* The following condition causes URIs with five leading / characters
2460       ** like file://///host/path to be converted into UNCs like //host/path.
2461       ** The correct URI for that UNC has only two or four leading / characters
2462       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2463       ** common error, we are told, so we handle it as a special case. */
2464       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2465     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2466       iIn = 16;
2467     }
2468 #else
2469     /* Discard the scheme and authority segments of the URI. */
2470     if( zUri[5]=='/' && zUri[6]=='/' ){
2471       iIn = 7;
2472       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2473       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2474         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2475             iIn-7, &zUri[7]);
2476         rc = SQLITE_ERROR;
2477         goto parse_uri_out;
2478       }
2479     }
2480 #endif
2481 
2482     /* Copy the filename and any query parameters into the zFile buffer.
2483     ** Decode %HH escape codes along the way.
2484     **
2485     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2486     ** on the parsing context. As follows:
2487     **
2488     **   0: Parsing file-name.
2489     **   1: Parsing name section of a name=value query parameter.
2490     **   2: Parsing value section of a name=value query parameter.
2491     */
2492     eState = 0;
2493     while( (c = zUri[iIn])!=0 && c!='#' ){
2494       iIn++;
2495       if( c=='%'
2496        && sqlite3Isxdigit(zUri[iIn])
2497        && sqlite3Isxdigit(zUri[iIn+1])
2498       ){
2499         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2500         octet += sqlite3HexToInt(zUri[iIn++]);
2501 
2502         assert( octet>=0 && octet<256 );
2503         if( octet==0 ){
2504           /* This branch is taken when "%00" appears within the URI. In this
2505           ** case we ignore all text in the remainder of the path, name or
2506           ** value currently being parsed. So ignore the current character
2507           ** and skip to the next "?", "=" or "&", as appropriate. */
2508           while( (c = zUri[iIn])!=0 && c!='#'
2509               && (eState!=0 || c!='?')
2510               && (eState!=1 || (c!='=' && c!='&'))
2511               && (eState!=2 || c!='&')
2512           ){
2513             iIn++;
2514           }
2515           continue;
2516         }
2517         c = octet;
2518       }else if( eState==1 && (c=='&' || c=='=') ){
2519         if( zFile[iOut-1]==0 ){
2520           /* An empty option name. Ignore this option altogether. */
2521           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2522           continue;
2523         }
2524         if( c=='&' ){
2525           zFile[iOut++] = '\0';
2526         }else{
2527           eState = 2;
2528         }
2529         c = 0;
2530       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2531         c = 0;
2532         eState = 1;
2533       }
2534       zFile[iOut++] = c;
2535     }
2536     if( eState==1 ) zFile[iOut++] = '\0';
2537     zFile[iOut++] = '\0';
2538     zFile[iOut++] = '\0';
2539 
2540     /* Check if there were any options specified that should be interpreted
2541     ** here. Options that are interpreted here include "vfs" and those that
2542     ** correspond to flags that may be passed to the sqlite3_open_v2()
2543     ** method. */
2544     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2545     while( zOpt[0] ){
2546       int nOpt = sqlite3Strlen30(zOpt);
2547       char *zVal = &zOpt[nOpt+1];
2548       int nVal = sqlite3Strlen30(zVal);
2549 
2550       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2551         zVfs = zVal;
2552       }else{
2553         struct OpenMode {
2554           const char *z;
2555           int mode;
2556         } *aMode = 0;
2557         char *zModeType = 0;
2558         int mask = 0;
2559         int limit = 0;
2560 
2561         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2562           static struct OpenMode aCacheMode[] = {
2563             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2564             { "private", SQLITE_OPEN_PRIVATECACHE },
2565             { 0, 0 }
2566           };
2567 
2568           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2569           aMode = aCacheMode;
2570           limit = mask;
2571           zModeType = "cache";
2572         }
2573         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2574           static struct OpenMode aOpenMode[] = {
2575             { "ro",  SQLITE_OPEN_READONLY },
2576             { "rw",  SQLITE_OPEN_READWRITE },
2577             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2578             { "memory", SQLITE_OPEN_MEMORY },
2579             { 0, 0 }
2580           };
2581 
2582           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2583                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2584           aMode = aOpenMode;
2585           limit = mask & flags;
2586           zModeType = "access";
2587         }
2588 
2589         if( aMode ){
2590           int i;
2591           int mode = 0;
2592           for(i=0; aMode[i].z; i++){
2593             const char *z = aMode[i].z;
2594             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2595               mode = aMode[i].mode;
2596               break;
2597             }
2598           }
2599           if( mode==0 ){
2600             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2601             rc = SQLITE_ERROR;
2602             goto parse_uri_out;
2603           }
2604           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2605             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2606                                         zModeType, zVal);
2607             rc = SQLITE_PERM;
2608             goto parse_uri_out;
2609           }
2610           flags = (flags & ~mask) | mode;
2611         }
2612       }
2613 
2614       zOpt = &zVal[nVal+1];
2615     }
2616 
2617   }else{
2618     zFile = sqlite3_malloc64(nUri+2);
2619     if( !zFile ) return SQLITE_NOMEM;
2620     memcpy(zFile, zUri, nUri);
2621     zFile[nUri] = '\0';
2622     zFile[nUri+1] = '\0';
2623     flags &= ~SQLITE_OPEN_URI;
2624   }
2625 
2626   *ppVfs = sqlite3_vfs_find(zVfs);
2627   if( *ppVfs==0 ){
2628     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2629     rc = SQLITE_ERROR;
2630   }
2631  parse_uri_out:
2632   if( rc!=SQLITE_OK ){
2633     sqlite3_free(zFile);
2634     zFile = 0;
2635   }
2636   *pFlags = flags;
2637   *pzFile = zFile;
2638   return rc;
2639 }
2640 
2641 
2642 /*
2643 ** This routine does the work of opening a database on behalf of
2644 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2645 ** is UTF-8 encoded.
2646 */
2647 static int openDatabase(
2648   const char *zFilename, /* Database filename UTF-8 encoded */
2649   sqlite3 **ppDb,        /* OUT: Returned database handle */
2650   unsigned int flags,    /* Operational flags */
2651   const char *zVfs       /* Name of the VFS to use */
2652 ){
2653   sqlite3 *db;                    /* Store allocated handle here */
2654   int rc;                         /* Return code */
2655   int isThreadsafe;               /* True for threadsafe connections */
2656   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2657   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2658 
2659 #ifdef SQLITE_ENABLE_API_ARMOR
2660   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2661 #endif
2662   *ppDb = 0;
2663 #ifndef SQLITE_OMIT_AUTOINIT
2664   rc = sqlite3_initialize();
2665   if( rc ) return rc;
2666 #endif
2667 
2668   /* Only allow sensible combinations of bits in the flags argument.
2669   ** Throw an error if any non-sense combination is used.  If we
2670   ** do not block illegal combinations here, it could trigger
2671   ** assert() statements in deeper layers.  Sensible combinations
2672   ** are:
2673   **
2674   **  1:  SQLITE_OPEN_READONLY
2675   **  2:  SQLITE_OPEN_READWRITE
2676   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2677   */
2678   assert( SQLITE_OPEN_READONLY  == 0x01 );
2679   assert( SQLITE_OPEN_READWRITE == 0x02 );
2680   assert( SQLITE_OPEN_CREATE    == 0x04 );
2681   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2682   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2683   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2684   if( ((1<<(flags&7)) & 0x46)==0 ){
2685     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2686   }
2687 
2688   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2689     isThreadsafe = 0;
2690   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2691     isThreadsafe = 0;
2692   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2693     isThreadsafe = 1;
2694   }else{
2695     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2696   }
2697   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2698     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2699   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2700     flags |= SQLITE_OPEN_SHAREDCACHE;
2701   }
2702 
2703   /* Remove harmful bits from the flags parameter
2704   **
2705   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2706   ** dealt with in the previous code block.  Besides these, the only
2707   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2708   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2709   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2710   ** off all other flags.
2711   */
2712   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2713                SQLITE_OPEN_EXCLUSIVE |
2714                SQLITE_OPEN_MAIN_DB |
2715                SQLITE_OPEN_TEMP_DB |
2716                SQLITE_OPEN_TRANSIENT_DB |
2717                SQLITE_OPEN_MAIN_JOURNAL |
2718                SQLITE_OPEN_TEMP_JOURNAL |
2719                SQLITE_OPEN_SUBJOURNAL |
2720                SQLITE_OPEN_MASTER_JOURNAL |
2721                SQLITE_OPEN_NOMUTEX |
2722                SQLITE_OPEN_FULLMUTEX |
2723                SQLITE_OPEN_WAL
2724              );
2725 
2726   /* Allocate the sqlite data structure */
2727   db = sqlite3MallocZero( sizeof(sqlite3) );
2728   if( db==0 ) goto opendb_out;
2729   if( isThreadsafe ){
2730     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2731     if( db->mutex==0 ){
2732       sqlite3_free(db);
2733       db = 0;
2734       goto opendb_out;
2735     }
2736   }
2737   sqlite3_mutex_enter(db->mutex);
2738   db->errMask = 0xff;
2739   db->nDb = 2;
2740   db->magic = SQLITE_MAGIC_BUSY;
2741   db->aDb = db->aDbStatic;
2742 
2743   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2744   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2745   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2746   db->autoCommit = 1;
2747   db->nextAutovac = -1;
2748   db->szMmap = sqlite3GlobalConfig.szMmap;
2749   db->nextPagesize = 0;
2750   db->nMaxSorterMmap = 0x7FFFFFFF;
2751   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2752 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2753                  | SQLITE_AutoIndex
2754 #endif
2755 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2756                  | SQLITE_CkptFullFSync
2757 #endif
2758 #if SQLITE_DEFAULT_FILE_FORMAT<4
2759                  | SQLITE_LegacyFileFmt
2760 #endif
2761 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2762                  | SQLITE_LoadExtension
2763 #endif
2764 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2765                  | SQLITE_RecTriggers
2766 #endif
2767 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2768                  | SQLITE_ForeignKeys
2769 #endif
2770 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2771                  | SQLITE_ReverseOrder
2772 #endif
2773 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2774                  | SQLITE_CellSizeCk
2775 #endif
2776       ;
2777   sqlite3HashInit(&db->aCollSeq);
2778 #ifndef SQLITE_OMIT_VIRTUALTABLE
2779   sqlite3HashInit(&db->aModule);
2780 #endif
2781 
2782   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2783   ** and UTF-16, so add a version for each to avoid any unnecessary
2784   ** conversions. The only error that can occur here is a malloc() failure.
2785   **
2786   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2787   ** functions:
2788   */
2789   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
2790   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
2791   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
2792   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2793   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2794   if( db->mallocFailed ){
2795     goto opendb_out;
2796   }
2797   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2798   ** strings is BINARY.
2799   */
2800   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
2801   assert( db->pDfltColl!=0 );
2802 
2803   /* Parse the filename/URI argument. */
2804   db->openFlags = flags;
2805   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2806   if( rc!=SQLITE_OK ){
2807     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
2808     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2809     sqlite3_free(zErrMsg);
2810     goto opendb_out;
2811   }
2812 
2813   /* Open the backend database driver */
2814   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2815                         flags | SQLITE_OPEN_MAIN_DB);
2816   if( rc!=SQLITE_OK ){
2817     if( rc==SQLITE_IOERR_NOMEM ){
2818       rc = SQLITE_NOMEM;
2819     }
2820     sqlite3Error(db, rc);
2821     goto opendb_out;
2822   }
2823   sqlite3BtreeEnter(db->aDb[0].pBt);
2824   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2825   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2826   sqlite3BtreeLeave(db->aDb[0].pBt);
2827   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2828 
2829   /* The default safety_level for the main database is 'full'; for the temp
2830   ** database it is 'NONE'. This matches the pager layer defaults.
2831   */
2832   db->aDb[0].zName = "main";
2833   db->aDb[0].safety_level = 3;
2834   db->aDb[1].zName = "temp";
2835   db->aDb[1].safety_level = 1;
2836 
2837   db->magic = SQLITE_MAGIC_OPEN;
2838   if( db->mallocFailed ){
2839     goto opendb_out;
2840   }
2841 
2842   /* Register all built-in functions, but do not attempt to read the
2843   ** database schema yet. This is delayed until the first time the database
2844   ** is accessed.
2845   */
2846   sqlite3Error(db, SQLITE_OK);
2847   sqlite3RegisterBuiltinFunctions(db);
2848 
2849   /* Load automatic extensions - extensions that have been registered
2850   ** using the sqlite3_automatic_extension() API.
2851   */
2852   rc = sqlite3_errcode(db);
2853   if( rc==SQLITE_OK ){
2854     sqlite3AutoLoadExtensions(db);
2855     rc = sqlite3_errcode(db);
2856     if( rc!=SQLITE_OK ){
2857       goto opendb_out;
2858     }
2859   }
2860 
2861 #ifdef SQLITE_ENABLE_FTS1
2862   if( !db->mallocFailed ){
2863     extern int sqlite3Fts1Init(sqlite3*);
2864     rc = sqlite3Fts1Init(db);
2865   }
2866 #endif
2867 
2868 #ifdef SQLITE_ENABLE_FTS2
2869   if( !db->mallocFailed && rc==SQLITE_OK ){
2870     extern int sqlite3Fts2Init(sqlite3*);
2871     rc = sqlite3Fts2Init(db);
2872   }
2873 #endif
2874 
2875 #ifdef SQLITE_ENABLE_FTS3
2876   if( !db->mallocFailed && rc==SQLITE_OK ){
2877     rc = sqlite3Fts3Init(db);
2878   }
2879 #endif
2880 
2881 #ifdef SQLITE_ENABLE_ICU
2882   if( !db->mallocFailed && rc==SQLITE_OK ){
2883     rc = sqlite3IcuInit(db);
2884   }
2885 #endif
2886 
2887 #ifdef SQLITE_ENABLE_RTREE
2888   if( !db->mallocFailed && rc==SQLITE_OK){
2889     rc = sqlite3RtreeInit(db);
2890   }
2891 #endif
2892 
2893 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2894   if( !db->mallocFailed && rc==SQLITE_OK){
2895     rc = sqlite3DbstatRegister(db);
2896   }
2897 #endif
2898 
2899   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2900   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2901   ** mode.  Doing nothing at all also makes NORMAL the default.
2902   */
2903 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2904   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2905   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2906                           SQLITE_DEFAULT_LOCKING_MODE);
2907 #endif
2908 
2909   if( rc ) sqlite3Error(db, rc);
2910 
2911   /* Enable the lookaside-malloc subsystem */
2912   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2913                         sqlite3GlobalConfig.nLookaside);
2914 
2915   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2916 
2917 opendb_out:
2918   sqlite3_free(zOpen);
2919   if( db ){
2920     assert( db->mutex!=0 || isThreadsafe==0
2921            || sqlite3GlobalConfig.bFullMutex==0 );
2922     sqlite3_mutex_leave(db->mutex);
2923   }
2924   rc = sqlite3_errcode(db);
2925   assert( db!=0 || rc==SQLITE_NOMEM );
2926   if( rc==SQLITE_NOMEM ){
2927     sqlite3_close(db);
2928     db = 0;
2929   }else if( rc!=SQLITE_OK ){
2930     db->magic = SQLITE_MAGIC_SICK;
2931   }
2932   *ppDb = db;
2933 #ifdef SQLITE_ENABLE_SQLLOG
2934   if( sqlite3GlobalConfig.xSqllog ){
2935     /* Opening a db handle. Fourth parameter is passed 0. */
2936     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2937     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2938   }
2939 #endif
2940   return rc & 0xff;
2941 }
2942 
2943 /*
2944 ** Open a new database handle.
2945 */
2946 int sqlite3_open(
2947   const char *zFilename,
2948   sqlite3 **ppDb
2949 ){
2950   return openDatabase(zFilename, ppDb,
2951                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2952 }
2953 int sqlite3_open_v2(
2954   const char *filename,   /* Database filename (UTF-8) */
2955   sqlite3 **ppDb,         /* OUT: SQLite db handle */
2956   int flags,              /* Flags */
2957   const char *zVfs        /* Name of VFS module to use */
2958 ){
2959   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
2960 }
2961 
2962 #ifndef SQLITE_OMIT_UTF16
2963 /*
2964 ** Open a new database handle.
2965 */
2966 int sqlite3_open16(
2967   const void *zFilename,
2968   sqlite3 **ppDb
2969 ){
2970   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
2971   sqlite3_value *pVal;
2972   int rc;
2973 
2974 #ifdef SQLITE_ENABLE_API_ARMOR
2975   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2976 #endif
2977   *ppDb = 0;
2978 #ifndef SQLITE_OMIT_AUTOINIT
2979   rc = sqlite3_initialize();
2980   if( rc ) return rc;
2981 #endif
2982   if( zFilename==0 ) zFilename = "\000\000";
2983   pVal = sqlite3ValueNew(0);
2984   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
2985   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
2986   if( zFilename8 ){
2987     rc = openDatabase(zFilename8, ppDb,
2988                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
2989     assert( *ppDb || rc==SQLITE_NOMEM );
2990     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
2991       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
2992     }
2993   }else{
2994     rc = SQLITE_NOMEM;
2995   }
2996   sqlite3ValueFree(pVal);
2997 
2998   return rc & 0xff;
2999 }
3000 #endif /* SQLITE_OMIT_UTF16 */
3001 
3002 /*
3003 ** Register a new collation sequence with the database handle db.
3004 */
3005 int sqlite3_create_collation(
3006   sqlite3* db,
3007   const char *zName,
3008   int enc,
3009   void* pCtx,
3010   int(*xCompare)(void*,int,const void*,int,const void*)
3011 ){
3012   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3013 }
3014 
3015 /*
3016 ** Register a new collation sequence with the database handle db.
3017 */
3018 int sqlite3_create_collation_v2(
3019   sqlite3* db,
3020   const char *zName,
3021   int enc,
3022   void* pCtx,
3023   int(*xCompare)(void*,int,const void*,int,const void*),
3024   void(*xDel)(void*)
3025 ){
3026   int rc;
3027 
3028 #ifdef SQLITE_ENABLE_API_ARMOR
3029   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3030 #endif
3031   sqlite3_mutex_enter(db->mutex);
3032   assert( !db->mallocFailed );
3033   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3034   rc = sqlite3ApiExit(db, rc);
3035   sqlite3_mutex_leave(db->mutex);
3036   return rc;
3037 }
3038 
3039 #ifndef SQLITE_OMIT_UTF16
3040 /*
3041 ** Register a new collation sequence with the database handle db.
3042 */
3043 int sqlite3_create_collation16(
3044   sqlite3* db,
3045   const void *zName,
3046   int enc,
3047   void* pCtx,
3048   int(*xCompare)(void*,int,const void*,int,const void*)
3049 ){
3050   int rc = SQLITE_OK;
3051   char *zName8;
3052 
3053 #ifdef SQLITE_ENABLE_API_ARMOR
3054   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3055 #endif
3056   sqlite3_mutex_enter(db->mutex);
3057   assert( !db->mallocFailed );
3058   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3059   if( zName8 ){
3060     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3061     sqlite3DbFree(db, zName8);
3062   }
3063   rc = sqlite3ApiExit(db, rc);
3064   sqlite3_mutex_leave(db->mutex);
3065   return rc;
3066 }
3067 #endif /* SQLITE_OMIT_UTF16 */
3068 
3069 /*
3070 ** Register a collation sequence factory callback with the database handle
3071 ** db. Replace any previously installed collation sequence factory.
3072 */
3073 int sqlite3_collation_needed(
3074   sqlite3 *db,
3075   void *pCollNeededArg,
3076   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3077 ){
3078 #ifdef SQLITE_ENABLE_API_ARMOR
3079   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3080 #endif
3081   sqlite3_mutex_enter(db->mutex);
3082   db->xCollNeeded = xCollNeeded;
3083   db->xCollNeeded16 = 0;
3084   db->pCollNeededArg = pCollNeededArg;
3085   sqlite3_mutex_leave(db->mutex);
3086   return SQLITE_OK;
3087 }
3088 
3089 #ifndef SQLITE_OMIT_UTF16
3090 /*
3091 ** Register a collation sequence factory callback with the database handle
3092 ** db. Replace any previously installed collation sequence factory.
3093 */
3094 int sqlite3_collation_needed16(
3095   sqlite3 *db,
3096   void *pCollNeededArg,
3097   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3098 ){
3099 #ifdef SQLITE_ENABLE_API_ARMOR
3100   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3101 #endif
3102   sqlite3_mutex_enter(db->mutex);
3103   db->xCollNeeded = 0;
3104   db->xCollNeeded16 = xCollNeeded16;
3105   db->pCollNeededArg = pCollNeededArg;
3106   sqlite3_mutex_leave(db->mutex);
3107   return SQLITE_OK;
3108 }
3109 #endif /* SQLITE_OMIT_UTF16 */
3110 
3111 #ifndef SQLITE_OMIT_DEPRECATED
3112 /*
3113 ** This function is now an anachronism. It used to be used to recover from a
3114 ** malloc() failure, but SQLite now does this automatically.
3115 */
3116 int sqlite3_global_recover(void){
3117   return SQLITE_OK;
3118 }
3119 #endif
3120 
3121 /*
3122 ** Test to see whether or not the database connection is in autocommit
3123 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3124 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3125 ** by the next COMMIT or ROLLBACK.
3126 */
3127 int sqlite3_get_autocommit(sqlite3 *db){
3128 #ifdef SQLITE_ENABLE_API_ARMOR
3129   if( !sqlite3SafetyCheckOk(db) ){
3130     (void)SQLITE_MISUSE_BKPT;
3131     return 0;
3132   }
3133 #endif
3134   return db->autoCommit;
3135 }
3136 
3137 /*
3138 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3139 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
3140 ** constants.  They serve two purposes:
3141 **
3142 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3143 **       to detect when version error conditions occurs.
3144 **
3145 **   2.  Invoke sqlite3_log() to provide the source code location where
3146 **       a low-level error is first detected.
3147 */
3148 int sqlite3CorruptError(int lineno){
3149   testcase( sqlite3GlobalConfig.xLog!=0 );
3150   sqlite3_log(SQLITE_CORRUPT,
3151               "database corruption at line %d of [%.10s]",
3152               lineno, 20+sqlite3_sourceid());
3153   return SQLITE_CORRUPT;
3154 }
3155 int sqlite3MisuseError(int lineno){
3156   testcase( sqlite3GlobalConfig.xLog!=0 );
3157   sqlite3_log(SQLITE_MISUSE,
3158               "misuse at line %d of [%.10s]",
3159               lineno, 20+sqlite3_sourceid());
3160   return SQLITE_MISUSE;
3161 }
3162 int sqlite3CantopenError(int lineno){
3163   testcase( sqlite3GlobalConfig.xLog!=0 );
3164   sqlite3_log(SQLITE_CANTOPEN,
3165               "cannot open file at line %d of [%.10s]",
3166               lineno, 20+sqlite3_sourceid());
3167   return SQLITE_CANTOPEN;
3168 }
3169 
3170 
3171 #ifndef SQLITE_OMIT_DEPRECATED
3172 /*
3173 ** This is a convenience routine that makes sure that all thread-specific
3174 ** data for this thread has been deallocated.
3175 **
3176 ** SQLite no longer uses thread-specific data so this routine is now a
3177 ** no-op.  It is retained for historical compatibility.
3178 */
3179 void sqlite3_thread_cleanup(void){
3180 }
3181 #endif
3182 
3183 /*
3184 ** Return meta information about a specific column of a database table.
3185 ** See comment in sqlite3.h (sqlite.h.in) for details.
3186 */
3187 int sqlite3_table_column_metadata(
3188   sqlite3 *db,                /* Connection handle */
3189   const char *zDbName,        /* Database name or NULL */
3190   const char *zTableName,     /* Table name */
3191   const char *zColumnName,    /* Column name */
3192   char const **pzDataType,    /* OUTPUT: Declared data type */
3193   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3194   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3195   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3196   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3197 ){
3198   int rc;
3199   char *zErrMsg = 0;
3200   Table *pTab = 0;
3201   Column *pCol = 0;
3202   int iCol = 0;
3203   char const *zDataType = 0;
3204   char const *zCollSeq = 0;
3205   int notnull = 0;
3206   int primarykey = 0;
3207   int autoinc = 0;
3208 
3209 
3210 #ifdef SQLITE_ENABLE_API_ARMOR
3211   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3212     return SQLITE_MISUSE_BKPT;
3213   }
3214 #endif
3215 
3216   /* Ensure the database schema has been loaded */
3217   sqlite3_mutex_enter(db->mutex);
3218   sqlite3BtreeEnterAll(db);
3219   rc = sqlite3Init(db, &zErrMsg);
3220   if( SQLITE_OK!=rc ){
3221     goto error_out;
3222   }
3223 
3224   /* Locate the table in question */
3225   pTab = sqlite3FindTable(db, zTableName, zDbName);
3226   if( !pTab || pTab->pSelect ){
3227     pTab = 0;
3228     goto error_out;
3229   }
3230 
3231   /* Find the column for which info is requested */
3232   if( zColumnName==0 ){
3233     /* Query for existance of table only */
3234   }else{
3235     for(iCol=0; iCol<pTab->nCol; iCol++){
3236       pCol = &pTab->aCol[iCol];
3237       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3238         break;
3239       }
3240     }
3241     if( iCol==pTab->nCol ){
3242       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3243         iCol = pTab->iPKey;
3244         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3245       }else{
3246         pTab = 0;
3247         goto error_out;
3248       }
3249     }
3250   }
3251 
3252   /* The following block stores the meta information that will be returned
3253   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3254   ** and autoinc. At this point there are two possibilities:
3255   **
3256   **     1. The specified column name was rowid", "oid" or "_rowid_"
3257   **        and there is no explicitly declared IPK column.
3258   **
3259   **     2. The table is not a view and the column name identified an
3260   **        explicitly declared column. Copy meta information from *pCol.
3261   */
3262   if( pCol ){
3263     zDataType = pCol->zType;
3264     zCollSeq = pCol->zColl;
3265     notnull = pCol->notNull!=0;
3266     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3267     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3268   }else{
3269     zDataType = "INTEGER";
3270     primarykey = 1;
3271   }
3272   if( !zCollSeq ){
3273     zCollSeq = "BINARY";
3274   }
3275 
3276 error_out:
3277   sqlite3BtreeLeaveAll(db);
3278 
3279   /* Whether the function call succeeded or failed, set the output parameters
3280   ** to whatever their local counterparts contain. If an error did occur,
3281   ** this has the effect of zeroing all output parameters.
3282   */
3283   if( pzDataType ) *pzDataType = zDataType;
3284   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3285   if( pNotNull ) *pNotNull = notnull;
3286   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3287   if( pAutoinc ) *pAutoinc = autoinc;
3288 
3289   if( SQLITE_OK==rc && !pTab ){
3290     sqlite3DbFree(db, zErrMsg);
3291     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3292         zColumnName);
3293     rc = SQLITE_ERROR;
3294   }
3295   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3296   sqlite3DbFree(db, zErrMsg);
3297   rc = sqlite3ApiExit(db, rc);
3298   sqlite3_mutex_leave(db->mutex);
3299   return rc;
3300 }
3301 
3302 /*
3303 ** Sleep for a little while.  Return the amount of time slept.
3304 */
3305 int sqlite3_sleep(int ms){
3306   sqlite3_vfs *pVfs;
3307   int rc;
3308   pVfs = sqlite3_vfs_find(0);
3309   if( pVfs==0 ) return 0;
3310 
3311   /* This function works in milliseconds, but the underlying OsSleep()
3312   ** API uses microseconds. Hence the 1000's.
3313   */
3314   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3315   return rc;
3316 }
3317 
3318 /*
3319 ** Enable or disable the extended result codes.
3320 */
3321 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3322 #ifdef SQLITE_ENABLE_API_ARMOR
3323   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3324 #endif
3325   sqlite3_mutex_enter(db->mutex);
3326   db->errMask = onoff ? 0xffffffff : 0xff;
3327   sqlite3_mutex_leave(db->mutex);
3328   return SQLITE_OK;
3329 }
3330 
3331 /*
3332 ** Invoke the xFileControl method on a particular database.
3333 */
3334 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3335   int rc = SQLITE_ERROR;
3336   Btree *pBtree;
3337 
3338 #ifdef SQLITE_ENABLE_API_ARMOR
3339   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3340 #endif
3341   sqlite3_mutex_enter(db->mutex);
3342   pBtree = sqlite3DbNameToBtree(db, zDbName);
3343   if( pBtree ){
3344     Pager *pPager;
3345     sqlite3_file *fd;
3346     sqlite3BtreeEnter(pBtree);
3347     pPager = sqlite3BtreePager(pBtree);
3348     assert( pPager!=0 );
3349     fd = sqlite3PagerFile(pPager);
3350     assert( fd!=0 );
3351     if( op==SQLITE_FCNTL_FILE_POINTER ){
3352       *(sqlite3_file**)pArg = fd;
3353       rc = SQLITE_OK;
3354     }else if( fd->pMethods ){
3355       rc = sqlite3OsFileControl(fd, op, pArg);
3356     }else{
3357       rc = SQLITE_NOTFOUND;
3358     }
3359     sqlite3BtreeLeave(pBtree);
3360   }
3361   sqlite3_mutex_leave(db->mutex);
3362   return rc;
3363 }
3364 
3365 /*
3366 ** Interface to the testing logic.
3367 */
3368 int sqlite3_test_control(int op, ...){
3369   int rc = 0;
3370 #ifdef SQLITE_OMIT_BUILTIN_TEST
3371   UNUSED_PARAMETER(op);
3372 #else
3373   va_list ap;
3374   va_start(ap, op);
3375   switch( op ){
3376 
3377     /*
3378     ** Save the current state of the PRNG.
3379     */
3380     case SQLITE_TESTCTRL_PRNG_SAVE: {
3381       sqlite3PrngSaveState();
3382       break;
3383     }
3384 
3385     /*
3386     ** Restore the state of the PRNG to the last state saved using
3387     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3388     ** this verb acts like PRNG_RESET.
3389     */
3390     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3391       sqlite3PrngRestoreState();
3392       break;
3393     }
3394 
3395     /*
3396     ** Reset the PRNG back to its uninitialized state.  The next call
3397     ** to sqlite3_randomness() will reseed the PRNG using a single call
3398     ** to the xRandomness method of the default VFS.
3399     */
3400     case SQLITE_TESTCTRL_PRNG_RESET: {
3401       sqlite3_randomness(0,0);
3402       break;
3403     }
3404 
3405     /*
3406     **  sqlite3_test_control(BITVEC_TEST, size, program)
3407     **
3408     ** Run a test against a Bitvec object of size.  The program argument
3409     ** is an array of integers that defines the test.  Return -1 on a
3410     ** memory allocation error, 0 on success, or non-zero for an error.
3411     ** See the sqlite3BitvecBuiltinTest() for additional information.
3412     */
3413     case SQLITE_TESTCTRL_BITVEC_TEST: {
3414       int sz = va_arg(ap, int);
3415       int *aProg = va_arg(ap, int*);
3416       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3417       break;
3418     }
3419 
3420     /*
3421     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3422     **
3423     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3424     ** if xCallback is not NULL.
3425     **
3426     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3427     ** is called immediately after installing the new callback and the return
3428     ** value from sqlite3FaultSim(0) becomes the return from
3429     ** sqlite3_test_control().
3430     */
3431     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3432       /* MSVC is picky about pulling func ptrs from va lists.
3433       ** http://support.microsoft.com/kb/47961
3434       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3435       */
3436       typedef int(*TESTCALLBACKFUNC_t)(int);
3437       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3438       rc = sqlite3FaultSim(0);
3439       break;
3440     }
3441 
3442     /*
3443     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3444     **
3445     ** Register hooks to call to indicate which malloc() failures
3446     ** are benign.
3447     */
3448     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3449       typedef void (*void_function)(void);
3450       void_function xBenignBegin;
3451       void_function xBenignEnd;
3452       xBenignBegin = va_arg(ap, void_function);
3453       xBenignEnd = va_arg(ap, void_function);
3454       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3455       break;
3456     }
3457 
3458     /*
3459     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3460     **
3461     ** Set the PENDING byte to the value in the argument, if X>0.
3462     ** Make no changes if X==0.  Return the value of the pending byte
3463     ** as it existing before this routine was called.
3464     **
3465     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3466     ** an incompatible database file format.  Changing the PENDING byte
3467     ** while any database connection is open results in undefined and
3468     ** deleterious behavior.
3469     */
3470     case SQLITE_TESTCTRL_PENDING_BYTE: {
3471       rc = PENDING_BYTE;
3472 #ifndef SQLITE_OMIT_WSD
3473       {
3474         unsigned int newVal = va_arg(ap, unsigned int);
3475         if( newVal ) sqlite3PendingByte = newVal;
3476       }
3477 #endif
3478       break;
3479     }
3480 
3481     /*
3482     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3483     **
3484     ** This action provides a run-time test to see whether or not
3485     ** assert() was enabled at compile-time.  If X is true and assert()
3486     ** is enabled, then the return value is true.  If X is true and
3487     ** assert() is disabled, then the return value is zero.  If X is
3488     ** false and assert() is enabled, then the assertion fires and the
3489     ** process aborts.  If X is false and assert() is disabled, then the
3490     ** return value is zero.
3491     */
3492     case SQLITE_TESTCTRL_ASSERT: {
3493       volatile int x = 0;
3494       assert( (x = va_arg(ap,int))!=0 );
3495       rc = x;
3496       break;
3497     }
3498 
3499 
3500     /*
3501     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3502     **
3503     ** This action provides a run-time test to see how the ALWAYS and
3504     ** NEVER macros were defined at compile-time.
3505     **
3506     ** The return value is ALWAYS(X).
3507     **
3508     ** The recommended test is X==2.  If the return value is 2, that means
3509     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3510     ** default setting.  If the return value is 1, then ALWAYS() is either
3511     ** hard-coded to true or else it asserts if its argument is false.
3512     ** The first behavior (hard-coded to true) is the case if
3513     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3514     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3515     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3516     **
3517     ** The run-time test procedure might look something like this:
3518     **
3519     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3520     **      // ALWAYS() and NEVER() are no-op pass-through macros
3521     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3522     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3523     **    }else{
3524     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3525     **    }
3526     */
3527     case SQLITE_TESTCTRL_ALWAYS: {
3528       int x = va_arg(ap,int);
3529       rc = ALWAYS(x);
3530       break;
3531     }
3532 
3533     /*
3534     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3535     **
3536     ** The integer returned reveals the byte-order of the computer on which
3537     ** SQLite is running:
3538     **
3539     **       1     big-endian,    determined at run-time
3540     **      10     little-endian, determined at run-time
3541     **  432101     big-endian,    determined at compile-time
3542     **  123410     little-endian, determined at compile-time
3543     */
3544     case SQLITE_TESTCTRL_BYTEORDER: {
3545       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3546       break;
3547     }
3548 
3549     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3550     **
3551     ** Set the nReserve size to N for the main database on the database
3552     ** connection db.
3553     */
3554     case SQLITE_TESTCTRL_RESERVE: {
3555       sqlite3 *db = va_arg(ap, sqlite3*);
3556       int x = va_arg(ap,int);
3557       sqlite3_mutex_enter(db->mutex);
3558       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3559       sqlite3_mutex_leave(db->mutex);
3560       break;
3561     }
3562 
3563     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3564     **
3565     ** Enable or disable various optimizations for testing purposes.  The
3566     ** argument N is a bitmask of optimizations to be disabled.  For normal
3567     ** operation N should be 0.  The idea is that a test program (like the
3568     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3569     ** with various optimizations disabled to verify that the same answer
3570     ** is obtained in every case.
3571     */
3572     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3573       sqlite3 *db = va_arg(ap, sqlite3*);
3574       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3575       break;
3576     }
3577 
3578 #ifdef SQLITE_N_KEYWORD
3579     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3580     **
3581     ** If zWord is a keyword recognized by the parser, then return the
3582     ** number of keywords.  Or if zWord is not a keyword, return 0.
3583     **
3584     ** This test feature is only available in the amalgamation since
3585     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3586     ** is built using separate source files.
3587     */
3588     case SQLITE_TESTCTRL_ISKEYWORD: {
3589       const char *zWord = va_arg(ap, const char*);
3590       int n = sqlite3Strlen30(zWord);
3591       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3592       break;
3593     }
3594 #endif
3595 
3596     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3597     **
3598     ** Pass pFree into sqlite3ScratchFree().
3599     ** If sz>0 then allocate a scratch buffer into pNew.
3600     */
3601     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3602       void *pFree, **ppNew;
3603       int sz;
3604       sz = va_arg(ap, int);
3605       ppNew = va_arg(ap, void**);
3606       pFree = va_arg(ap, void*);
3607       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3608       sqlite3ScratchFree(pFree);
3609       break;
3610     }
3611 
3612     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3613     **
3614     ** If parameter onoff is non-zero, configure the wrappers so that all
3615     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3616     ** undo this setting.
3617     */
3618     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3619       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3620       break;
3621     }
3622 
3623     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3624     **
3625     ** Set or clear a flag that indicates that the database file is always well-
3626     ** formed and never corrupt.  This flag is clear by default, indicating that
3627     ** database files might have arbitrary corruption.  Setting the flag during
3628     ** testing causes certain assert() statements in the code to be activated
3629     ** that demonstrat invariants on well-formed database files.
3630     */
3631     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3632       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3633       break;
3634     }
3635 
3636 
3637     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3638     **
3639     ** Set the VDBE coverage callback function to xCallback with context
3640     ** pointer ptr.
3641     */
3642     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3643 #ifdef SQLITE_VDBE_COVERAGE
3644       typedef void (*branch_callback)(void*,int,u8,u8);
3645       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3646       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3647 #endif
3648       break;
3649     }
3650 
3651     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3652     case SQLITE_TESTCTRL_SORTER_MMAP: {
3653       sqlite3 *db = va_arg(ap, sqlite3*);
3654       db->nMaxSorterMmap = va_arg(ap, int);
3655       break;
3656     }
3657 
3658     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3659     **
3660     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3661     ** not.
3662     */
3663     case SQLITE_TESTCTRL_ISINIT: {
3664       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3665       break;
3666     }
3667 
3668     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3669     **
3670     ** This test control is used to create imposter tables.  "db" is a pointer
3671     ** to the database connection.  dbName is the database name (ex: "main" or
3672     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3673     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3674     ** table should connect.
3675     **
3676     ** Enable imposter mode only when the schema has already been parsed.  Then
3677     ** run a single CREATE TABLE statement to construct the imposter table in
3678     ** the parsed schema.  Then turn imposter mode back off again.
3679     **
3680     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3681     ** the schema to be reparsed the next time it is needed.  This has the
3682     ** effect of erasing all imposter tables.
3683     */
3684     case SQLITE_TESTCTRL_IMPOSTER: {
3685       sqlite3 *db = va_arg(ap, sqlite3*);
3686       sqlite3_mutex_enter(db->mutex);
3687       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3688       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3689       db->init.newTnum = va_arg(ap,int);
3690       if( db->init.busy==0 && db->init.newTnum>0 ){
3691         sqlite3ResetAllSchemasOfConnection(db);
3692       }
3693       sqlite3_mutex_leave(db->mutex);
3694       break;
3695     }
3696   }
3697   va_end(ap);
3698 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3699   return rc;
3700 }
3701 
3702 /*
3703 ** This is a utility routine, useful to VFS implementations, that checks
3704 ** to see if a database file was a URI that contained a specific query
3705 ** parameter, and if so obtains the value of the query parameter.
3706 **
3707 ** The zFilename argument is the filename pointer passed into the xOpen()
3708 ** method of a VFS implementation.  The zParam argument is the name of the
3709 ** query parameter we seek.  This routine returns the value of the zParam
3710 ** parameter if it exists.  If the parameter does not exist, this routine
3711 ** returns a NULL pointer.
3712 */
3713 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3714   if( zFilename==0 || zParam==0 ) return 0;
3715   zFilename += sqlite3Strlen30(zFilename) + 1;
3716   while( zFilename[0] ){
3717     int x = strcmp(zFilename, zParam);
3718     zFilename += sqlite3Strlen30(zFilename) + 1;
3719     if( x==0 ) return zFilename;
3720     zFilename += sqlite3Strlen30(zFilename) + 1;
3721   }
3722   return 0;
3723 }
3724 
3725 /*
3726 ** Return a boolean value for a query parameter.
3727 */
3728 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3729   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3730   bDflt = bDflt!=0;
3731   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3732 }
3733 
3734 /*
3735 ** Return a 64-bit integer value for a query parameter.
3736 */
3737 sqlite3_int64 sqlite3_uri_int64(
3738   const char *zFilename,    /* Filename as passed to xOpen */
3739   const char *zParam,       /* URI parameter sought */
3740   sqlite3_int64 bDflt       /* return if parameter is missing */
3741 ){
3742   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3743   sqlite3_int64 v;
3744   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3745     bDflt = v;
3746   }
3747   return bDflt;
3748 }
3749 
3750 /*
3751 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3752 */
3753 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3754   int i;
3755   for(i=0; i<db->nDb; i++){
3756     if( db->aDb[i].pBt
3757      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3758     ){
3759       return db->aDb[i].pBt;
3760     }
3761   }
3762   return 0;
3763 }
3764 
3765 /*
3766 ** Return the filename of the database associated with a database
3767 ** connection.
3768 */
3769 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3770   Btree *pBt;
3771 #ifdef SQLITE_ENABLE_API_ARMOR
3772   if( !sqlite3SafetyCheckOk(db) ){
3773     (void)SQLITE_MISUSE_BKPT;
3774     return 0;
3775   }
3776 #endif
3777   pBt = sqlite3DbNameToBtree(db, zDbName);
3778   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3779 }
3780 
3781 /*
3782 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3783 ** no such database exists.
3784 */
3785 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3786   Btree *pBt;
3787 #ifdef SQLITE_ENABLE_API_ARMOR
3788   if( !sqlite3SafetyCheckOk(db) ){
3789     (void)SQLITE_MISUSE_BKPT;
3790     return -1;
3791   }
3792 #endif
3793   pBt = sqlite3DbNameToBtree(db, zDbName);
3794   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3795 }
3796