xref: /sqlite-3.40.0/src/main.c (revision d82211db)
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 #ifdef SQLITE_ENABLE_JSON1
29 int sqlite3Json1Init(sqlite3*);
30 #endif
31 #ifdef SQLITE_ENABLE_FTS5
32 int sqlite3Fts5Init(sqlite3*);
33 #endif
34 
35 #ifndef SQLITE_AMALGAMATION
36 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
37 ** contains the text of SQLITE_VERSION macro.
38 */
39 const char sqlite3_version[] = SQLITE_VERSION;
40 #endif
41 
42 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
43 ** a pointer to the to the sqlite3_version[] string constant.
44 */
45 const char *sqlite3_libversion(void){ return sqlite3_version; }
46 
47 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
48 ** pointer to a string constant whose value is the same as the
49 ** SQLITE_SOURCE_ID C preprocessor macro.
50 */
51 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
52 
53 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
54 ** returns an integer equal to SQLITE_VERSION_NUMBER.
55 */
56 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
57 
58 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
59 ** zero if and only if SQLite was compiled with mutexing code omitted due to
60 ** the SQLITE_THREADSAFE compile-time option being set to 0.
61 */
62 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
63 
64 /*
65 ** When compiling the test fixture or with debugging enabled (on Win32),
66 ** this variable being set to non-zero will cause OSTRACE macros to emit
67 ** extra diagnostic information.
68 */
69 #ifdef SQLITE_HAVE_OS_TRACE
70 # ifndef SQLITE_DEBUG_OS_TRACE
71 #   define SQLITE_DEBUG_OS_TRACE 0
72 # endif
73   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
74 #endif
75 
76 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
77 /*
78 ** If the following function pointer is not NULL and if
79 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
80 ** I/O active are written using this function.  These messages
81 ** are intended for debugging activity only.
82 */
83 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
84 #endif
85 
86 /*
87 ** If the following global variable points to a string which is the
88 ** name of a directory, then that directory will be used to store
89 ** temporary files.
90 **
91 ** See also the "PRAGMA temp_store_directory" SQL command.
92 */
93 char *sqlite3_temp_directory = 0;
94 
95 /*
96 ** If the following global variable points to a string which is the
97 ** name of a directory, then that directory will be used to store
98 ** all database files specified with a relative pathname.
99 **
100 ** See also the "PRAGMA data_store_directory" SQL command.
101 */
102 char *sqlite3_data_directory = 0;
103 
104 /*
105 ** Initialize SQLite.
106 **
107 ** This routine must be called to initialize the memory allocation,
108 ** VFS, and mutex subsystems prior to doing any serious work with
109 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
110 ** this routine will be called automatically by key routines such as
111 ** sqlite3_open().
112 **
113 ** This routine is a no-op except on its very first call for the process,
114 ** or for the first call after a call to sqlite3_shutdown.
115 **
116 ** The first thread to call this routine runs the initialization to
117 ** completion.  If subsequent threads call this routine before the first
118 ** thread has finished the initialization process, then the subsequent
119 ** threads must block until the first thread finishes with the initialization.
120 **
121 ** The first thread might call this routine recursively.  Recursive
122 ** calls to this routine should not block, of course.  Otherwise the
123 ** initialization process would never complete.
124 **
125 ** Let X be the first thread to enter this routine.  Let Y be some other
126 ** thread.  Then while the initial invocation of this routine by X is
127 ** incomplete, it is required that:
128 **
129 **    *  Calls to this routine from Y must block until the outer-most
130 **       call by X completes.
131 **
132 **    *  Recursive calls to this routine from thread X return immediately
133 **       without blocking.
134 */
135 int sqlite3_initialize(void){
136   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
137   int rc;                                      /* Result code */
138 #ifdef SQLITE_EXTRA_INIT
139   int bRunExtraInit = 0;                       /* Extra initialization needed */
140 #endif
141 
142 #ifdef SQLITE_OMIT_WSD
143   rc = sqlite3_wsd_init(4096, 24);
144   if( rc!=SQLITE_OK ){
145     return rc;
146   }
147 #endif
148 
149   /* If the following assert() fails on some obscure processor/compiler
150   ** combination, the work-around is to set the correct pointer
151   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
152   assert( SQLITE_PTRSIZE==sizeof(char*) );
153 
154   /* If SQLite is already completely initialized, then this call
155   ** to sqlite3_initialize() should be a no-op.  But the initialization
156   ** must be complete.  So isInit must not be set until the very end
157   ** of this routine.
158   */
159   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
160 
161   /* Make sure the mutex subsystem is initialized.  If unable to
162   ** initialize the mutex subsystem, return early with the error.
163   ** If the system is so sick that we are unable to allocate a mutex,
164   ** there is not much SQLite is going to be able to do.
165   **
166   ** The mutex subsystem must take care of serializing its own
167   ** initialization.
168   */
169   rc = sqlite3MutexInit();
170   if( rc ) return rc;
171 
172   /* Initialize the malloc() system and the recursive pInitMutex mutex.
173   ** This operation is protected by the STATIC_MASTER mutex.  Note that
174   ** MutexAlloc() is called for a static mutex prior to initializing the
175   ** malloc subsystem - this implies that the allocation of a static
176   ** mutex must not require support from the malloc subsystem.
177   */
178   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
179   sqlite3_mutex_enter(pMaster);
180   sqlite3GlobalConfig.isMutexInit = 1;
181   if( !sqlite3GlobalConfig.isMallocInit ){
182     rc = sqlite3MallocInit();
183   }
184   if( rc==SQLITE_OK ){
185     sqlite3GlobalConfig.isMallocInit = 1;
186     if( !sqlite3GlobalConfig.pInitMutex ){
187       sqlite3GlobalConfig.pInitMutex =
188            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
189       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
190         rc = SQLITE_NOMEM;
191       }
192     }
193   }
194   if( rc==SQLITE_OK ){
195     sqlite3GlobalConfig.nRefInitMutex++;
196   }
197   sqlite3_mutex_leave(pMaster);
198 
199   /* If rc is not SQLITE_OK at this point, then either the malloc
200   ** subsystem could not be initialized or the system failed to allocate
201   ** the pInitMutex mutex. Return an error in either case.  */
202   if( rc!=SQLITE_OK ){
203     return rc;
204   }
205 
206   /* Do the rest of the initialization under the recursive mutex so
207   ** that we will be able to handle recursive calls into
208   ** sqlite3_initialize().  The recursive calls normally come through
209   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
210   ** recursive calls might also be possible.
211   **
212   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
213   ** to the xInit method, so the xInit method need not be threadsafe.
214   **
215   ** The following mutex is what serializes access to the appdef pcache xInit
216   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
217   ** call to sqlite3PcacheInitialize().
218   */
219   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
220   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
221     FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions);
222     sqlite3GlobalConfig.inProgress = 1;
223     memset(pHash, 0, sizeof(sqlite3GlobalFunctions));
224     sqlite3RegisterGlobalFunctions();
225     if( sqlite3GlobalConfig.isPCacheInit==0 ){
226       rc = sqlite3PcacheInitialize();
227     }
228     if( rc==SQLITE_OK ){
229       sqlite3GlobalConfig.isPCacheInit = 1;
230       rc = sqlite3OsInit();
231     }
232     if( rc==SQLITE_OK ){
233       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
234           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
235       sqlite3GlobalConfig.isInit = 1;
236 #ifdef SQLITE_EXTRA_INIT
237       bRunExtraInit = 1;
238 #endif
239     }
240     sqlite3GlobalConfig.inProgress = 0;
241   }
242   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
243 
244   /* Go back under the static mutex and clean up the recursive
245   ** mutex to prevent a resource leak.
246   */
247   sqlite3_mutex_enter(pMaster);
248   sqlite3GlobalConfig.nRefInitMutex--;
249   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
250     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
251     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
252     sqlite3GlobalConfig.pInitMutex = 0;
253   }
254   sqlite3_mutex_leave(pMaster);
255 
256   /* The following is just a sanity check to make sure SQLite has
257   ** been compiled correctly.  It is important to run this code, but
258   ** we don't want to run it too often and soak up CPU cycles for no
259   ** reason.  So we run it once during initialization.
260   */
261 #ifndef NDEBUG
262 #ifndef SQLITE_OMIT_FLOATING_POINT
263   /* This section of code's only "output" is via assert() statements. */
264   if ( rc==SQLITE_OK ){
265     u64 x = (((u64)1)<<63)-1;
266     double y;
267     assert(sizeof(x)==8);
268     assert(sizeof(x)==sizeof(y));
269     memcpy(&y, &x, 8);
270     assert( sqlite3IsNaN(y) );
271   }
272 #endif
273 #endif
274 
275   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
276   ** compile-time option.
277   */
278 #ifdef SQLITE_EXTRA_INIT
279   if( bRunExtraInit ){
280     int SQLITE_EXTRA_INIT(const char*);
281     rc = SQLITE_EXTRA_INIT(0);
282   }
283 #endif
284 
285   return rc;
286 }
287 
288 /*
289 ** Undo the effects of sqlite3_initialize().  Must not be called while
290 ** there are outstanding database connections or memory allocations or
291 ** while any part of SQLite is otherwise in use in any thread.  This
292 ** routine is not threadsafe.  But it is safe to invoke this routine
293 ** on when SQLite is already shut down.  If SQLite is already shut down
294 ** when this routine is invoked, then this routine is a harmless no-op.
295 */
296 int sqlite3_shutdown(void){
297 #ifdef SQLITE_OMIT_WSD
298   int rc = sqlite3_wsd_init(4096, 24);
299   if( rc!=SQLITE_OK ){
300     return rc;
301   }
302 #endif
303 
304   if( sqlite3GlobalConfig.isInit ){
305 #ifdef SQLITE_EXTRA_SHUTDOWN
306     void SQLITE_EXTRA_SHUTDOWN(void);
307     SQLITE_EXTRA_SHUTDOWN();
308 #endif
309     sqlite3_os_end();
310     sqlite3_reset_auto_extension();
311     sqlite3GlobalConfig.isInit = 0;
312   }
313   if( sqlite3GlobalConfig.isPCacheInit ){
314     sqlite3PcacheShutdown();
315     sqlite3GlobalConfig.isPCacheInit = 0;
316   }
317   if( sqlite3GlobalConfig.isMallocInit ){
318     sqlite3MallocEnd();
319     sqlite3GlobalConfig.isMallocInit = 0;
320 
321 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
322     /* The heap subsystem has now been shutdown and these values are supposed
323     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
324     ** which would rely on that heap subsystem; therefore, make sure these
325     ** values cannot refer to heap memory that was just invalidated when the
326     ** heap subsystem was shutdown.  This is only done if the current call to
327     ** this function resulted in the heap subsystem actually being shutdown.
328     */
329     sqlite3_data_directory = 0;
330     sqlite3_temp_directory = 0;
331 #endif
332   }
333   if( sqlite3GlobalConfig.isMutexInit ){
334     sqlite3MutexEnd();
335     sqlite3GlobalConfig.isMutexInit = 0;
336   }
337 
338   return SQLITE_OK;
339 }
340 
341 /*
342 ** This API allows applications to modify the global configuration of
343 ** the SQLite library at run-time.
344 **
345 ** This routine should only be called when there are no outstanding
346 ** database connections or memory allocations.  This routine is not
347 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
348 ** behavior.
349 */
350 int sqlite3_config(int op, ...){
351   va_list ap;
352   int rc = SQLITE_OK;
353 
354   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
355   ** the SQLite library is in use. */
356   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
357 
358   va_start(ap, op);
359   switch( op ){
360 
361     /* Mutex configuration options are only available in a threadsafe
362     ** compile.
363     */
364 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
365     case SQLITE_CONFIG_SINGLETHREAD: {
366       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
367       ** Single-thread. */
368       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
369       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
370       break;
371     }
372 #endif
373 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
374     case SQLITE_CONFIG_MULTITHREAD: {
375       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
376       ** Multi-thread. */
377       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
378       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
379       break;
380     }
381 #endif
382 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
383     case SQLITE_CONFIG_SERIALIZED: {
384       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
385       ** Serialized. */
386       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
387       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
388       break;
389     }
390 #endif
391 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
392     case SQLITE_CONFIG_MUTEX: {
393       /* Specify an alternative mutex implementation */
394       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
395       break;
396     }
397 #endif
398 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
399     case SQLITE_CONFIG_GETMUTEX: {
400       /* Retrieve the current mutex implementation */
401       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
402       break;
403     }
404 #endif
405 
406     case SQLITE_CONFIG_MALLOC: {
407       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
408       ** single argument which is a pointer to an instance of the
409       ** sqlite3_mem_methods structure. The argument specifies alternative
410       ** low-level memory allocation routines to be used in place of the memory
411       ** allocation routines built into SQLite. */
412       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
413       break;
414     }
415     case SQLITE_CONFIG_GETMALLOC: {
416       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
417       ** single argument which is a pointer to an instance of the
418       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
419       ** filled with the currently defined memory allocation routines. */
420       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
421       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
422       break;
423     }
424     case SQLITE_CONFIG_MEMSTATUS: {
425       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
426       ** single argument of type int, interpreted as a boolean, which enables
427       ** or disables the collection of memory allocation statistics. */
428       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
429       break;
430     }
431     case SQLITE_CONFIG_SCRATCH: {
432       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
433       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
434       ** which the scratch allocations will be drawn, the size of each scratch
435       ** allocation (sz), and the maximum number of scratch allocations (N). */
436       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
437       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
438       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
439       break;
440     }
441     case SQLITE_CONFIG_PAGECACHE: {
442       /* EVIDENCE-OF: R-31408-40510 There are three arguments to
443       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size
444       ** of each page buffer (sz), and the number of pages (N). */
445       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
446       sqlite3GlobalConfig.szPage = va_arg(ap, int);
447       sqlite3GlobalConfig.nPage = va_arg(ap, int);
448       break;
449     }
450     case SQLITE_CONFIG_PCACHE_HDRSZ: {
451       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
452       ** a single parameter which is a pointer to an integer and writes into
453       ** that integer the number of extra bytes per page required for each page
454       ** in SQLITE_CONFIG_PAGECACHE. */
455       *va_arg(ap, int*) =
456           sqlite3HeaderSizeBtree() +
457           sqlite3HeaderSizePcache() +
458           sqlite3HeaderSizePcache1();
459       break;
460     }
461 
462     case SQLITE_CONFIG_PCACHE: {
463       /* no-op */
464       break;
465     }
466     case SQLITE_CONFIG_GETPCACHE: {
467       /* now an error */
468       rc = SQLITE_ERROR;
469       break;
470     }
471 
472     case SQLITE_CONFIG_PCACHE2: {
473       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
474       ** single argument which is a pointer to an sqlite3_pcache_methods2
475       ** object. This object specifies the interface to a custom page cache
476       ** implementation. */
477       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
478       break;
479     }
480     case SQLITE_CONFIG_GETPCACHE2: {
481       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
482       ** single argument which is a pointer to an sqlite3_pcache_methods2
483       ** object. SQLite copies of the current page cache implementation into
484       ** that object. */
485       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
486         sqlite3PCacheSetDefault();
487       }
488       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
489       break;
490     }
491 
492 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
493 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
494 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
495 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
496     case SQLITE_CONFIG_HEAP: {
497       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
498       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
499       ** number of bytes in the memory buffer, and the minimum allocation size.
500       */
501       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
502       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
503       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
504 
505       if( sqlite3GlobalConfig.mnReq<1 ){
506         sqlite3GlobalConfig.mnReq = 1;
507       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
508         /* cap min request size at 2^12 */
509         sqlite3GlobalConfig.mnReq = (1<<12);
510       }
511 
512       if( sqlite3GlobalConfig.pHeap==0 ){
513         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
514         ** is NULL, then SQLite reverts to using its default memory allocator
515         ** (the system malloc() implementation), undoing any prior invocation of
516         ** SQLITE_CONFIG_MALLOC.
517         **
518         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
519         ** revert to its default implementation when sqlite3_initialize() is run
520         */
521         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
522       }else{
523         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
524         ** alternative memory allocator is engaged to handle all of SQLites
525         ** memory allocation needs. */
526 #ifdef SQLITE_ENABLE_MEMSYS3
527         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
528 #endif
529 #ifdef SQLITE_ENABLE_MEMSYS5
530         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
531 #endif
532       }
533       break;
534     }
535 #endif
536 
537     case SQLITE_CONFIG_LOOKASIDE: {
538       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
539       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
540       break;
541     }
542 
543     /* Record a pointer to the logger function and its first argument.
544     ** The default is NULL.  Logging is disabled if the function pointer is
545     ** NULL.
546     */
547     case SQLITE_CONFIG_LOG: {
548       /* MSVC is picky about pulling func ptrs from va lists.
549       ** http://support.microsoft.com/kb/47961
550       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
551       */
552       typedef void(*LOGFUNC_t)(void*,int,const char*);
553       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
554       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
555       break;
556     }
557 
558     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
559     ** can be changed at start-time using the
560     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
561     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
562     */
563     case SQLITE_CONFIG_URI: {
564       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
565       ** argument of type int. If non-zero, then URI handling is globally
566       ** enabled. If the parameter is zero, then URI handling is globally
567       ** disabled. */
568       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
569       break;
570     }
571 
572     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
573       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
574       ** option takes a single integer argument which is interpreted as a
575       ** boolean in order to enable or disable the use of covering indices for
576       ** full table scans in the query optimizer. */
577       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
578       break;
579     }
580 
581 #ifdef SQLITE_ENABLE_SQLLOG
582     case SQLITE_CONFIG_SQLLOG: {
583       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
584       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
585       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
586       break;
587     }
588 #endif
589 
590     case SQLITE_CONFIG_MMAP_SIZE: {
591       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
592       ** integer (sqlite3_int64) values that are the default mmap size limit
593       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
594       ** mmap size limit. */
595       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
596       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
597       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
598       ** negative, then that argument is changed to its compile-time default.
599       **
600       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
601       ** silently truncated if necessary so that it does not exceed the
602       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
603       ** compile-time option.
604       */
605       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
606         mxMmap = SQLITE_MAX_MMAP_SIZE;
607       }
608       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
609       if( szMmap>mxMmap) szMmap = mxMmap;
610       sqlite3GlobalConfig.mxMmap = mxMmap;
611       sqlite3GlobalConfig.szMmap = szMmap;
612       break;
613     }
614 
615 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
616     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
617       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
618       ** unsigned integer value that specifies the maximum size of the created
619       ** heap. */
620       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
621       break;
622     }
623 #endif
624 
625     case SQLITE_CONFIG_PMASZ: {
626       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
627       break;
628     }
629 
630     default: {
631       rc = SQLITE_ERROR;
632       break;
633     }
634   }
635   va_end(ap);
636   return rc;
637 }
638 
639 /*
640 ** Set up the lookaside buffers for a database connection.
641 ** Return SQLITE_OK on success.
642 ** If lookaside is already active, return SQLITE_BUSY.
643 **
644 ** The sz parameter is the number of bytes in each lookaside slot.
645 ** The cnt parameter is the number of slots.  If pStart is NULL the
646 ** space for the lookaside memory is obtained from sqlite3_malloc().
647 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
648 ** the lookaside memory.
649 */
650 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
651 #ifndef SQLITE_OMIT_LOOKASIDE
652   void *pStart;
653   if( db->lookaside.nOut ){
654     return SQLITE_BUSY;
655   }
656   /* Free any existing lookaside buffer for this handle before
657   ** allocating a new one so we don't have to have space for
658   ** both at the same time.
659   */
660   if( db->lookaside.bMalloced ){
661     sqlite3_free(db->lookaside.pStart);
662   }
663   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
664   ** than a pointer to be useful.
665   */
666   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
667   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
668   if( cnt<0 ) cnt = 0;
669   if( sz==0 || cnt==0 ){
670     sz = 0;
671     pStart = 0;
672   }else if( pBuf==0 ){
673     sqlite3BeginBenignMalloc();
674     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
675     sqlite3EndBenignMalloc();
676     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
677   }else{
678     pStart = pBuf;
679   }
680   db->lookaside.pStart = pStart;
681   db->lookaside.pFree = 0;
682   db->lookaside.sz = (u16)sz;
683   if( pStart ){
684     int i;
685     LookasideSlot *p;
686     assert( sz > (int)sizeof(LookasideSlot*) );
687     p = (LookasideSlot*)pStart;
688     for(i=cnt-1; i>=0; i--){
689       p->pNext = db->lookaside.pFree;
690       db->lookaside.pFree = p;
691       p = (LookasideSlot*)&((u8*)p)[sz];
692     }
693     db->lookaside.pEnd = p;
694     db->lookaside.bEnabled = 1;
695     db->lookaside.bMalloced = pBuf==0 ?1:0;
696   }else{
697     db->lookaside.pStart = db;
698     db->lookaside.pEnd = db;
699     db->lookaside.bEnabled = 0;
700     db->lookaside.bMalloced = 0;
701   }
702 #endif /* SQLITE_OMIT_LOOKASIDE */
703   return SQLITE_OK;
704 }
705 
706 /*
707 ** Return the mutex associated with a database connection.
708 */
709 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
710 #ifdef SQLITE_ENABLE_API_ARMOR
711   if( !sqlite3SafetyCheckOk(db) ){
712     (void)SQLITE_MISUSE_BKPT;
713     return 0;
714   }
715 #endif
716   return db->mutex;
717 }
718 
719 /*
720 ** Free up as much memory as we can from the given database
721 ** connection.
722 */
723 int sqlite3_db_release_memory(sqlite3 *db){
724   int i;
725 
726 #ifdef SQLITE_ENABLE_API_ARMOR
727   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
728 #endif
729   sqlite3_mutex_enter(db->mutex);
730   sqlite3BtreeEnterAll(db);
731   for(i=0; i<db->nDb; i++){
732     Btree *pBt = db->aDb[i].pBt;
733     if( pBt ){
734       Pager *pPager = sqlite3BtreePager(pBt);
735       sqlite3PagerShrink(pPager);
736     }
737   }
738   sqlite3BtreeLeaveAll(db);
739   sqlite3_mutex_leave(db->mutex);
740   return SQLITE_OK;
741 }
742 
743 /*
744 ** Flush any dirty pages in the pager-cache for any attached database
745 ** to disk.
746 */
747 int sqlite3_db_cacheflush(sqlite3 *db){
748   int i;
749   int rc = SQLITE_OK;
750   int bSeenBusy = 0;
751 
752 #ifdef SQLITE_ENABLE_API_ARMOR
753   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
754 #endif
755   sqlite3_mutex_enter(db->mutex);
756   sqlite3BtreeEnterAll(db);
757   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
758     Btree *pBt = db->aDb[i].pBt;
759     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
760       Pager *pPager = sqlite3BtreePager(pBt);
761       rc = sqlite3PagerFlush(pPager);
762       if( rc==SQLITE_BUSY ){
763         bSeenBusy = 1;
764         rc = SQLITE_OK;
765       }
766     }
767   }
768   sqlite3BtreeLeaveAll(db);
769   sqlite3_mutex_leave(db->mutex);
770   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
771 }
772 
773 /*
774 ** Configuration settings for an individual database connection
775 */
776 int sqlite3_db_config(sqlite3 *db, int op, ...){
777   va_list ap;
778   int rc;
779   va_start(ap, op);
780   switch( op ){
781     case SQLITE_DBCONFIG_LOOKASIDE: {
782       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
783       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
784       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
785       rc = setupLookaside(db, pBuf, sz, cnt);
786       break;
787     }
788     default: {
789       static const struct {
790         int op;      /* The opcode */
791         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
792       } aFlagOp[] = {
793         { SQLITE_DBCONFIG_ENABLE_FKEY,    SQLITE_ForeignKeys    },
794         { SQLITE_DBCONFIG_ENABLE_TRIGGER, SQLITE_EnableTrigger  },
795       };
796       unsigned int i;
797       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
798       for(i=0; i<ArraySize(aFlagOp); i++){
799         if( aFlagOp[i].op==op ){
800           int onoff = va_arg(ap, int);
801           int *pRes = va_arg(ap, int*);
802           int oldFlags = db->flags;
803           if( onoff>0 ){
804             db->flags |= aFlagOp[i].mask;
805           }else if( onoff==0 ){
806             db->flags &= ~aFlagOp[i].mask;
807           }
808           if( oldFlags!=db->flags ){
809             sqlite3ExpirePreparedStatements(db);
810           }
811           if( pRes ){
812             *pRes = (db->flags & aFlagOp[i].mask)!=0;
813           }
814           rc = SQLITE_OK;
815           break;
816         }
817       }
818       break;
819     }
820   }
821   va_end(ap);
822   return rc;
823 }
824 
825 
826 /*
827 ** Return true if the buffer z[0..n-1] contains all spaces.
828 */
829 static int allSpaces(const char *z, int n){
830   while( n>0 && z[n-1]==' ' ){ n--; }
831   return n==0;
832 }
833 
834 /*
835 ** This is the default collating function named "BINARY" which is always
836 ** available.
837 **
838 ** If the padFlag argument is not NULL then space padding at the end
839 ** of strings is ignored.  This implements the RTRIM collation.
840 */
841 static int binCollFunc(
842   void *padFlag,
843   int nKey1, const void *pKey1,
844   int nKey2, const void *pKey2
845 ){
846   int rc, n;
847   n = nKey1<nKey2 ? nKey1 : nKey2;
848   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
849   ** strings byte by byte using the memcmp() function from the standard C
850   ** library. */
851   rc = memcmp(pKey1, pKey2, n);
852   if( rc==0 ){
853     if( padFlag
854      && allSpaces(((char*)pKey1)+n, nKey1-n)
855      && allSpaces(((char*)pKey2)+n, nKey2-n)
856     ){
857       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
858       ** spaces at the end of either string do not change the result. In other
859       ** words, strings will compare equal to one another as long as they
860       ** differ only in the number of spaces at the end.
861       */
862     }else{
863       rc = nKey1 - nKey2;
864     }
865   }
866   return rc;
867 }
868 
869 /*
870 ** Another built-in collating sequence: NOCASE.
871 **
872 ** This collating sequence is intended to be used for "case independent
873 ** comparison". SQLite's knowledge of upper and lower case equivalents
874 ** extends only to the 26 characters used in the English language.
875 **
876 ** At the moment there is only a UTF-8 implementation.
877 */
878 static int nocaseCollatingFunc(
879   void *NotUsed,
880   int nKey1, const void *pKey1,
881   int nKey2, const void *pKey2
882 ){
883   int r = sqlite3StrNICmp(
884       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
885   UNUSED_PARAMETER(NotUsed);
886   if( 0==r ){
887     r = nKey1-nKey2;
888   }
889   return r;
890 }
891 
892 /*
893 ** Return the ROWID of the most recent insert
894 */
895 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
896 #ifdef SQLITE_ENABLE_API_ARMOR
897   if( !sqlite3SafetyCheckOk(db) ){
898     (void)SQLITE_MISUSE_BKPT;
899     return 0;
900   }
901 #endif
902   return db->lastRowid;
903 }
904 
905 /*
906 ** Return the number of changes in the most recent call to sqlite3_exec().
907 */
908 int sqlite3_changes(sqlite3 *db){
909 #ifdef SQLITE_ENABLE_API_ARMOR
910   if( !sqlite3SafetyCheckOk(db) ){
911     (void)SQLITE_MISUSE_BKPT;
912     return 0;
913   }
914 #endif
915   return db->nChange;
916 }
917 
918 /*
919 ** Return the number of changes since the database handle was opened.
920 */
921 int sqlite3_total_changes(sqlite3 *db){
922 #ifdef SQLITE_ENABLE_API_ARMOR
923   if( !sqlite3SafetyCheckOk(db) ){
924     (void)SQLITE_MISUSE_BKPT;
925     return 0;
926   }
927 #endif
928   return db->nTotalChange;
929 }
930 
931 /*
932 ** Close all open savepoints. This function only manipulates fields of the
933 ** database handle object, it does not close any savepoints that may be open
934 ** at the b-tree/pager level.
935 */
936 void sqlite3CloseSavepoints(sqlite3 *db){
937   while( db->pSavepoint ){
938     Savepoint *pTmp = db->pSavepoint;
939     db->pSavepoint = pTmp->pNext;
940     sqlite3DbFree(db, pTmp);
941   }
942   db->nSavepoint = 0;
943   db->nStatement = 0;
944   db->isTransactionSavepoint = 0;
945 }
946 
947 /*
948 ** Invoke the destructor function associated with FuncDef p, if any. Except,
949 ** if this is not the last copy of the function, do not invoke it. Multiple
950 ** copies of a single function are created when create_function() is called
951 ** with SQLITE_ANY as the encoding.
952 */
953 static void functionDestroy(sqlite3 *db, FuncDef *p){
954   FuncDestructor *pDestructor = p->pDestructor;
955   if( pDestructor ){
956     pDestructor->nRef--;
957     if( pDestructor->nRef==0 ){
958       pDestructor->xDestroy(pDestructor->pUserData);
959       sqlite3DbFree(db, pDestructor);
960     }
961   }
962 }
963 
964 /*
965 ** Disconnect all sqlite3_vtab objects that belong to database connection
966 ** db. This is called when db is being closed.
967 */
968 static void disconnectAllVtab(sqlite3 *db){
969 #ifndef SQLITE_OMIT_VIRTUALTABLE
970   int i;
971   HashElem *p;
972   sqlite3BtreeEnterAll(db);
973   for(i=0; i<db->nDb; i++){
974     Schema *pSchema = db->aDb[i].pSchema;
975     if( db->aDb[i].pSchema ){
976       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
977         Table *pTab = (Table *)sqliteHashData(p);
978         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
979       }
980     }
981   }
982   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
983     Module *pMod = (Module *)sqliteHashData(p);
984     if( pMod->pEpoTab ){
985       sqlite3VtabDisconnect(db, pMod->pEpoTab);
986     }
987   }
988   sqlite3VtabUnlockList(db);
989   sqlite3BtreeLeaveAll(db);
990 #else
991   UNUSED_PARAMETER(db);
992 #endif
993 }
994 
995 /*
996 ** Return TRUE if database connection db has unfinalized prepared
997 ** statements or unfinished sqlite3_backup objects.
998 */
999 static int connectionIsBusy(sqlite3 *db){
1000   int j;
1001   assert( sqlite3_mutex_held(db->mutex) );
1002   if( db->pVdbe ) return 1;
1003   for(j=0; j<db->nDb; j++){
1004     Btree *pBt = db->aDb[j].pBt;
1005     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1006   }
1007   return 0;
1008 }
1009 
1010 /*
1011 ** Close an existing SQLite database
1012 */
1013 static int sqlite3Close(sqlite3 *db, int forceZombie){
1014   if( !db ){
1015     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1016     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1017     return SQLITE_OK;
1018   }
1019   if( !sqlite3SafetyCheckSickOrOk(db) ){
1020     return SQLITE_MISUSE_BKPT;
1021   }
1022   sqlite3_mutex_enter(db->mutex);
1023 
1024   /* Force xDisconnect calls on all virtual tables */
1025   disconnectAllVtab(db);
1026 
1027   /* If a transaction is open, the disconnectAllVtab() call above
1028   ** will not have called the xDisconnect() method on any virtual
1029   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1030   ** call will do so. We need to do this before the check for active
1031   ** SQL statements below, as the v-table implementation may be storing
1032   ** some prepared statements internally.
1033   */
1034   sqlite3VtabRollback(db);
1035 
1036   /* Legacy behavior (sqlite3_close() behavior) is to return
1037   ** SQLITE_BUSY if the connection can not be closed immediately.
1038   */
1039   if( !forceZombie && connectionIsBusy(db) ){
1040     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1041        "statements or unfinished backups");
1042     sqlite3_mutex_leave(db->mutex);
1043     return SQLITE_BUSY;
1044   }
1045 
1046 #ifdef SQLITE_ENABLE_SQLLOG
1047   if( sqlite3GlobalConfig.xSqllog ){
1048     /* Closing the handle. Fourth parameter is passed the value 2. */
1049     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1050   }
1051 #endif
1052 
1053   /* Convert the connection into a zombie and then close it.
1054   */
1055   db->magic = SQLITE_MAGIC_ZOMBIE;
1056   sqlite3LeaveMutexAndCloseZombie(db);
1057   return SQLITE_OK;
1058 }
1059 
1060 /*
1061 ** Two variations on the public interface for closing a database
1062 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1063 ** leaves the connection option if there are unfinalized prepared
1064 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1065 ** version forces the connection to become a zombie if there are
1066 ** unclosed resources, and arranges for deallocation when the last
1067 ** prepare statement or sqlite3_backup closes.
1068 */
1069 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1070 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1071 
1072 
1073 /*
1074 ** Close the mutex on database connection db.
1075 **
1076 ** Furthermore, if database connection db is a zombie (meaning that there
1077 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1078 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1079 ** finished, then free all resources.
1080 */
1081 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1082   HashElem *i;                    /* Hash table iterator */
1083   int j;
1084 
1085   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1086   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1087   ** then just leave the mutex and return.
1088   */
1089   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1090     sqlite3_mutex_leave(db->mutex);
1091     return;
1092   }
1093 
1094   /* If we reach this point, it means that the database connection has
1095   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1096   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1097   ** go ahead and free all resources.
1098   */
1099 
1100   /* If a transaction is open, roll it back. This also ensures that if
1101   ** any database schemas have been modified by an uncommitted transaction
1102   ** they are reset. And that the required b-tree mutex is held to make
1103   ** the pager rollback and schema reset an atomic operation. */
1104   sqlite3RollbackAll(db, SQLITE_OK);
1105 
1106   /* Free any outstanding Savepoint structures. */
1107   sqlite3CloseSavepoints(db);
1108 
1109   /* Close all database connections */
1110   for(j=0; j<db->nDb; j++){
1111     struct Db *pDb = &db->aDb[j];
1112     if( pDb->pBt ){
1113       sqlite3BtreeClose(pDb->pBt);
1114       pDb->pBt = 0;
1115       if( j!=1 ){
1116         pDb->pSchema = 0;
1117       }
1118     }
1119   }
1120   /* Clear the TEMP schema separately and last */
1121   if( db->aDb[1].pSchema ){
1122     sqlite3SchemaClear(db->aDb[1].pSchema);
1123   }
1124   sqlite3VtabUnlockList(db);
1125 
1126   /* Free up the array of auxiliary databases */
1127   sqlite3CollapseDatabaseArray(db);
1128   assert( db->nDb<=2 );
1129   assert( db->aDb==db->aDbStatic );
1130 
1131   /* Tell the code in notify.c that the connection no longer holds any
1132   ** locks and does not require any further unlock-notify callbacks.
1133   */
1134   sqlite3ConnectionClosed(db);
1135 
1136   for(j=0; j<ArraySize(db->aFunc.a); j++){
1137     FuncDef *pNext, *pHash, *p;
1138     for(p=db->aFunc.a[j]; p; p=pHash){
1139       pHash = p->pHash;
1140       while( p ){
1141         functionDestroy(db, p);
1142         pNext = p->pNext;
1143         sqlite3DbFree(db, p);
1144         p = pNext;
1145       }
1146     }
1147   }
1148   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1149     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1150     /* Invoke any destructors registered for collation sequence user data. */
1151     for(j=0; j<3; j++){
1152       if( pColl[j].xDel ){
1153         pColl[j].xDel(pColl[j].pUser);
1154       }
1155     }
1156     sqlite3DbFree(db, pColl);
1157   }
1158   sqlite3HashClear(&db->aCollSeq);
1159 #ifndef SQLITE_OMIT_VIRTUALTABLE
1160   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1161     Module *pMod = (Module *)sqliteHashData(i);
1162     if( pMod->xDestroy ){
1163       pMod->xDestroy(pMod->pAux);
1164     }
1165     sqlite3VtabEponymousTableClear(db, pMod);
1166     sqlite3DbFree(db, pMod);
1167   }
1168   sqlite3HashClear(&db->aModule);
1169 #endif
1170 
1171   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1172   sqlite3ValueFree(db->pErr);
1173   sqlite3CloseExtensions(db);
1174 #if SQLITE_USER_AUTHENTICATION
1175   sqlite3_free(db->auth.zAuthUser);
1176   sqlite3_free(db->auth.zAuthPW);
1177 #endif
1178 
1179   db->magic = SQLITE_MAGIC_ERROR;
1180 
1181   /* The temp-database schema is allocated differently from the other schema
1182   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1183   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1184   ** the same sqliteMalloc() as the one that allocates the database
1185   ** structure?
1186   */
1187   sqlite3DbFree(db, db->aDb[1].pSchema);
1188   sqlite3_mutex_leave(db->mutex);
1189   db->magic = SQLITE_MAGIC_CLOSED;
1190   sqlite3_mutex_free(db->mutex);
1191   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1192   if( db->lookaside.bMalloced ){
1193     sqlite3_free(db->lookaside.pStart);
1194   }
1195   sqlite3_free(db);
1196 }
1197 
1198 /*
1199 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1200 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1201 ** breaker") and made to return tripCode if there are any further
1202 ** attempts to use that cursor.  Read cursors remain open and valid
1203 ** but are "saved" in case the table pages are moved around.
1204 */
1205 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1206   int i;
1207   int inTrans = 0;
1208   int schemaChange;
1209   assert( sqlite3_mutex_held(db->mutex) );
1210   sqlite3BeginBenignMalloc();
1211 
1212   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1213   ** This is important in case the transaction being rolled back has
1214   ** modified the database schema. If the b-tree mutexes are not taken
1215   ** here, then another shared-cache connection might sneak in between
1216   ** the database rollback and schema reset, which can cause false
1217   ** corruption reports in some cases.  */
1218   sqlite3BtreeEnterAll(db);
1219   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1220 
1221   for(i=0; i<db->nDb; i++){
1222     Btree *p = db->aDb[i].pBt;
1223     if( p ){
1224       if( sqlite3BtreeIsInTrans(p) ){
1225         inTrans = 1;
1226       }
1227       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1228     }
1229   }
1230   sqlite3VtabRollback(db);
1231   sqlite3EndBenignMalloc();
1232 
1233   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1234     sqlite3ExpirePreparedStatements(db);
1235     sqlite3ResetAllSchemasOfConnection(db);
1236   }
1237   sqlite3BtreeLeaveAll(db);
1238 
1239   /* Any deferred constraint violations have now been resolved. */
1240   db->nDeferredCons = 0;
1241   db->nDeferredImmCons = 0;
1242   db->flags &= ~SQLITE_DeferFKs;
1243 
1244   /* If one has been configured, invoke the rollback-hook callback */
1245   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1246     db->xRollbackCallback(db->pRollbackArg);
1247   }
1248 }
1249 
1250 /*
1251 ** Return a static string containing the name corresponding to the error code
1252 ** specified in the argument.
1253 */
1254 #if defined(SQLITE_NEED_ERR_NAME)
1255 const char *sqlite3ErrName(int rc){
1256   const char *zName = 0;
1257   int i, origRc = rc;
1258   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1259     switch( rc ){
1260       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1261       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1262       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1263       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1264       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1265       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1266       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1267       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1268       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1269       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1270       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1271       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1272       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1273       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1274       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1275       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1276       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1277       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1278       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1279       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1280       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1281       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1282       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1283       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1284       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1285       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1286       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1287       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1288       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1289       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1290       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1291       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1292                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1293       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1294       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1295       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1296       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1297       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1298       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1299       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1300       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1301       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1302       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1303       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1304       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1305       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1306       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1307       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1308       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1309       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1310       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1311       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1312       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1313       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1314       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1315       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1316       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1317       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1318       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1319       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1320       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1321       case SQLITE_CONSTRAINT_FOREIGNKEY:
1322                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1323       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1324       case SQLITE_CONSTRAINT_PRIMARYKEY:
1325                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1326       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1327       case SQLITE_CONSTRAINT_COMMITHOOK:
1328                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1329       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1330       case SQLITE_CONSTRAINT_FUNCTION:
1331                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1332       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1333       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1334       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1335       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1336       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1337       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1338       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1339       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1340       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1341       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1342       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1343       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1344                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1345       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1346       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1347       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1348     }
1349   }
1350   if( zName==0 ){
1351     static char zBuf[50];
1352     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1353     zName = zBuf;
1354   }
1355   return zName;
1356 }
1357 #endif
1358 
1359 /*
1360 ** Return a static string that describes the kind of error specified in the
1361 ** argument.
1362 */
1363 const char *sqlite3ErrStr(int rc){
1364   static const char* const aMsg[] = {
1365     /* SQLITE_OK          */ "not an error",
1366     /* SQLITE_ERROR       */ "SQL logic error or missing database",
1367     /* SQLITE_INTERNAL    */ 0,
1368     /* SQLITE_PERM        */ "access permission denied",
1369     /* SQLITE_ABORT       */ "callback requested query abort",
1370     /* SQLITE_BUSY        */ "database is locked",
1371     /* SQLITE_LOCKED      */ "database table is locked",
1372     /* SQLITE_NOMEM       */ "out of memory",
1373     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1374     /* SQLITE_INTERRUPT   */ "interrupted",
1375     /* SQLITE_IOERR       */ "disk I/O error",
1376     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1377     /* SQLITE_NOTFOUND    */ "unknown operation",
1378     /* SQLITE_FULL        */ "database or disk is full",
1379     /* SQLITE_CANTOPEN    */ "unable to open database file",
1380     /* SQLITE_PROTOCOL    */ "locking protocol",
1381     /* SQLITE_EMPTY       */ "table contains no data",
1382     /* SQLITE_SCHEMA      */ "database schema has changed",
1383     /* SQLITE_TOOBIG      */ "string or blob too big",
1384     /* SQLITE_CONSTRAINT  */ "constraint failed",
1385     /* SQLITE_MISMATCH    */ "datatype mismatch",
1386     /* SQLITE_MISUSE      */ "library routine called out of sequence",
1387     /* SQLITE_NOLFS       */ "large file support is disabled",
1388     /* SQLITE_AUTH        */ "authorization denied",
1389     /* SQLITE_FORMAT      */ "auxiliary database format error",
1390     /* SQLITE_RANGE       */ "bind or column index out of range",
1391     /* SQLITE_NOTADB      */ "file is encrypted or is not a database",
1392   };
1393   const char *zErr = "unknown error";
1394   switch( rc ){
1395     case SQLITE_ABORT_ROLLBACK: {
1396       zErr = "abort due to ROLLBACK";
1397       break;
1398     }
1399     default: {
1400       rc &= 0xff;
1401       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1402         zErr = aMsg[rc];
1403       }
1404       break;
1405     }
1406   }
1407   return zErr;
1408 }
1409 
1410 /*
1411 ** This routine implements a busy callback that sleeps and tries
1412 ** again until a timeout value is reached.  The timeout value is
1413 ** an integer number of milliseconds passed in as the first
1414 ** argument.
1415 */
1416 static int sqliteDefaultBusyCallback(
1417  void *ptr,               /* Database connection */
1418  int count                /* Number of times table has been busy */
1419 ){
1420 #if SQLITE_OS_WIN || HAVE_USLEEP
1421   static const u8 delays[] =
1422      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1423   static const u8 totals[] =
1424      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1425 # define NDELAY ArraySize(delays)
1426   sqlite3 *db = (sqlite3 *)ptr;
1427   int timeout = db->busyTimeout;
1428   int delay, prior;
1429 
1430   assert( count>=0 );
1431   if( count < NDELAY ){
1432     delay = delays[count];
1433     prior = totals[count];
1434   }else{
1435     delay = delays[NDELAY-1];
1436     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1437   }
1438   if( prior + delay > timeout ){
1439     delay = timeout - prior;
1440     if( delay<=0 ) return 0;
1441   }
1442   sqlite3OsSleep(db->pVfs, delay*1000);
1443   return 1;
1444 #else
1445   sqlite3 *db = (sqlite3 *)ptr;
1446   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1447   if( (count+1)*1000 > timeout ){
1448     return 0;
1449   }
1450   sqlite3OsSleep(db->pVfs, 1000000);
1451   return 1;
1452 #endif
1453 }
1454 
1455 /*
1456 ** Invoke the given busy handler.
1457 **
1458 ** This routine is called when an operation failed with a lock.
1459 ** If this routine returns non-zero, the lock is retried.  If it
1460 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1461 */
1462 int sqlite3InvokeBusyHandler(BusyHandler *p){
1463   int rc;
1464   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1465   rc = p->xFunc(p->pArg, p->nBusy);
1466   if( rc==0 ){
1467     p->nBusy = -1;
1468   }else{
1469     p->nBusy++;
1470   }
1471   return rc;
1472 }
1473 
1474 /*
1475 ** This routine sets the busy callback for an Sqlite database to the
1476 ** given callback function with the given argument.
1477 */
1478 int sqlite3_busy_handler(
1479   sqlite3 *db,
1480   int (*xBusy)(void*,int),
1481   void *pArg
1482 ){
1483 #ifdef SQLITE_ENABLE_API_ARMOR
1484   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1485 #endif
1486   sqlite3_mutex_enter(db->mutex);
1487   db->busyHandler.xFunc = xBusy;
1488   db->busyHandler.pArg = pArg;
1489   db->busyHandler.nBusy = 0;
1490   db->busyTimeout = 0;
1491   sqlite3_mutex_leave(db->mutex);
1492   return SQLITE_OK;
1493 }
1494 
1495 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1496 /*
1497 ** This routine sets the progress callback for an Sqlite database to the
1498 ** given callback function with the given argument. The progress callback will
1499 ** be invoked every nOps opcodes.
1500 */
1501 void sqlite3_progress_handler(
1502   sqlite3 *db,
1503   int nOps,
1504   int (*xProgress)(void*),
1505   void *pArg
1506 ){
1507 #ifdef SQLITE_ENABLE_API_ARMOR
1508   if( !sqlite3SafetyCheckOk(db) ){
1509     (void)SQLITE_MISUSE_BKPT;
1510     return;
1511   }
1512 #endif
1513   sqlite3_mutex_enter(db->mutex);
1514   if( nOps>0 ){
1515     db->xProgress = xProgress;
1516     db->nProgressOps = (unsigned)nOps;
1517     db->pProgressArg = pArg;
1518   }else{
1519     db->xProgress = 0;
1520     db->nProgressOps = 0;
1521     db->pProgressArg = 0;
1522   }
1523   sqlite3_mutex_leave(db->mutex);
1524 }
1525 #endif
1526 
1527 
1528 /*
1529 ** This routine installs a default busy handler that waits for the
1530 ** specified number of milliseconds before returning 0.
1531 */
1532 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1533 #ifdef SQLITE_ENABLE_API_ARMOR
1534   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1535 #endif
1536   if( ms>0 ){
1537     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1538     db->busyTimeout = ms;
1539   }else{
1540     sqlite3_busy_handler(db, 0, 0);
1541   }
1542   return SQLITE_OK;
1543 }
1544 
1545 /*
1546 ** Cause any pending operation to stop at its earliest opportunity.
1547 */
1548 void sqlite3_interrupt(sqlite3 *db){
1549 #ifdef SQLITE_ENABLE_API_ARMOR
1550   if( !sqlite3SafetyCheckOk(db) ){
1551     (void)SQLITE_MISUSE_BKPT;
1552     return;
1553   }
1554 #endif
1555   db->u1.isInterrupted = 1;
1556 }
1557 
1558 
1559 /*
1560 ** This function is exactly the same as sqlite3_create_function(), except
1561 ** that it is designed to be called by internal code. The difference is
1562 ** that if a malloc() fails in sqlite3_create_function(), an error code
1563 ** is returned and the mallocFailed flag cleared.
1564 */
1565 int sqlite3CreateFunc(
1566   sqlite3 *db,
1567   const char *zFunctionName,
1568   int nArg,
1569   int enc,
1570   void *pUserData,
1571   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1572   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1573   void (*xFinal)(sqlite3_context*),
1574   FuncDestructor *pDestructor
1575 ){
1576   FuncDef *p;
1577   int nName;
1578   int extraFlags;
1579 
1580   assert( sqlite3_mutex_held(db->mutex) );
1581   if( zFunctionName==0 ||
1582       (xFunc && (xFinal || xStep)) ||
1583       (!xFunc && (xFinal && !xStep)) ||
1584       (!xFunc && (!xFinal && xStep)) ||
1585       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1586       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1587     return SQLITE_MISUSE_BKPT;
1588   }
1589 
1590   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1591   extraFlags = enc &  SQLITE_DETERMINISTIC;
1592   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1593 
1594 #ifndef SQLITE_OMIT_UTF16
1595   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1596   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1597   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1598   **
1599   ** If SQLITE_ANY is specified, add three versions of the function
1600   ** to the hash table.
1601   */
1602   if( enc==SQLITE_UTF16 ){
1603     enc = SQLITE_UTF16NATIVE;
1604   }else if( enc==SQLITE_ANY ){
1605     int rc;
1606     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1607          pUserData, xFunc, xStep, xFinal, pDestructor);
1608     if( rc==SQLITE_OK ){
1609       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1610           pUserData, xFunc, xStep, xFinal, pDestructor);
1611     }
1612     if( rc!=SQLITE_OK ){
1613       return rc;
1614     }
1615     enc = SQLITE_UTF16BE;
1616   }
1617 #else
1618   enc = SQLITE_UTF8;
1619 #endif
1620 
1621   /* Check if an existing function is being overridden or deleted. If so,
1622   ** and there are active VMs, then return SQLITE_BUSY. If a function
1623   ** is being overridden/deleted but there are no active VMs, allow the
1624   ** operation to continue but invalidate all precompiled statements.
1625   */
1626   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 0);
1627   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1628     if( db->nVdbeActive ){
1629       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1630         "unable to delete/modify user-function due to active statements");
1631       assert( !db->mallocFailed );
1632       return SQLITE_BUSY;
1633     }else{
1634       sqlite3ExpirePreparedStatements(db);
1635     }
1636   }
1637 
1638   p = sqlite3FindFunction(db, zFunctionName, nName, nArg, (u8)enc, 1);
1639   assert(p || db->mallocFailed);
1640   if( !p ){
1641     return SQLITE_NOMEM;
1642   }
1643 
1644   /* If an older version of the function with a configured destructor is
1645   ** being replaced invoke the destructor function here. */
1646   functionDestroy(db, p);
1647 
1648   if( pDestructor ){
1649     pDestructor->nRef++;
1650   }
1651   p->pDestructor = pDestructor;
1652   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1653   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1654   p->xFunc = xFunc;
1655   p->xStep = xStep;
1656   p->xFinalize = xFinal;
1657   p->pUserData = pUserData;
1658   p->nArg = (u16)nArg;
1659   return SQLITE_OK;
1660 }
1661 
1662 /*
1663 ** Create new user functions.
1664 */
1665 int sqlite3_create_function(
1666   sqlite3 *db,
1667   const char *zFunc,
1668   int nArg,
1669   int enc,
1670   void *p,
1671   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1672   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1673   void (*xFinal)(sqlite3_context*)
1674 ){
1675   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xFunc, xStep,
1676                                     xFinal, 0);
1677 }
1678 
1679 int sqlite3_create_function_v2(
1680   sqlite3 *db,
1681   const char *zFunc,
1682   int nArg,
1683   int enc,
1684   void *p,
1685   void (*xFunc)(sqlite3_context*,int,sqlite3_value **),
1686   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1687   void (*xFinal)(sqlite3_context*),
1688   void (*xDestroy)(void *)
1689 ){
1690   int rc = SQLITE_ERROR;
1691   FuncDestructor *pArg = 0;
1692 
1693 #ifdef SQLITE_ENABLE_API_ARMOR
1694   if( !sqlite3SafetyCheckOk(db) ){
1695     return SQLITE_MISUSE_BKPT;
1696   }
1697 #endif
1698   sqlite3_mutex_enter(db->mutex);
1699   if( xDestroy ){
1700     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1701     if( !pArg ){
1702       xDestroy(p);
1703       goto out;
1704     }
1705     pArg->xDestroy = xDestroy;
1706     pArg->pUserData = p;
1707   }
1708   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xFunc, xStep, xFinal, pArg);
1709   if( pArg && pArg->nRef==0 ){
1710     assert( rc!=SQLITE_OK );
1711     xDestroy(p);
1712     sqlite3DbFree(db, pArg);
1713   }
1714 
1715  out:
1716   rc = sqlite3ApiExit(db, rc);
1717   sqlite3_mutex_leave(db->mutex);
1718   return rc;
1719 }
1720 
1721 #ifndef SQLITE_OMIT_UTF16
1722 int sqlite3_create_function16(
1723   sqlite3 *db,
1724   const void *zFunctionName,
1725   int nArg,
1726   int eTextRep,
1727   void *p,
1728   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1729   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1730   void (*xFinal)(sqlite3_context*)
1731 ){
1732   int rc;
1733   char *zFunc8;
1734 
1735 #ifdef SQLITE_ENABLE_API_ARMOR
1736   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1737 #endif
1738   sqlite3_mutex_enter(db->mutex);
1739   assert( !db->mallocFailed );
1740   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1741   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xFunc, xStep, xFinal,0);
1742   sqlite3DbFree(db, zFunc8);
1743   rc = sqlite3ApiExit(db, rc);
1744   sqlite3_mutex_leave(db->mutex);
1745   return rc;
1746 }
1747 #endif
1748 
1749 
1750 /*
1751 ** Declare that a function has been overloaded by a virtual table.
1752 **
1753 ** If the function already exists as a regular global function, then
1754 ** this routine is a no-op.  If the function does not exist, then create
1755 ** a new one that always throws a run-time error.
1756 **
1757 ** When virtual tables intend to provide an overloaded function, they
1758 ** should call this routine to make sure the global function exists.
1759 ** A global function must exist in order for name resolution to work
1760 ** properly.
1761 */
1762 int sqlite3_overload_function(
1763   sqlite3 *db,
1764   const char *zName,
1765   int nArg
1766 ){
1767   int nName = sqlite3Strlen30(zName);
1768   int rc = SQLITE_OK;
1769 
1770 #ifdef SQLITE_ENABLE_API_ARMOR
1771   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1772     return SQLITE_MISUSE_BKPT;
1773   }
1774 #endif
1775   sqlite3_mutex_enter(db->mutex);
1776   if( sqlite3FindFunction(db, zName, nName, nArg, SQLITE_UTF8, 0)==0 ){
1777     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1778                            0, sqlite3InvalidFunction, 0, 0, 0);
1779   }
1780   rc = sqlite3ApiExit(db, rc);
1781   sqlite3_mutex_leave(db->mutex);
1782   return rc;
1783 }
1784 
1785 #ifndef SQLITE_OMIT_TRACE
1786 /*
1787 ** Register a trace function.  The pArg from the previously registered trace
1788 ** is returned.
1789 **
1790 ** A NULL trace function means that no tracing is executes.  A non-NULL
1791 ** trace is a pointer to a function that is invoked at the start of each
1792 ** SQL statement.
1793 */
1794 void *sqlite3_trace(sqlite3 *db, void (*xTrace)(void*,const char*), void *pArg){
1795   void *pOld;
1796 
1797 #ifdef SQLITE_ENABLE_API_ARMOR
1798   if( !sqlite3SafetyCheckOk(db) ){
1799     (void)SQLITE_MISUSE_BKPT;
1800     return 0;
1801   }
1802 #endif
1803   sqlite3_mutex_enter(db->mutex);
1804   pOld = db->pTraceArg;
1805   db->xTrace = xTrace;
1806   db->pTraceArg = pArg;
1807   sqlite3_mutex_leave(db->mutex);
1808   return pOld;
1809 }
1810 /*
1811 ** Register a profile function.  The pArg from the previously registered
1812 ** profile function is returned.
1813 **
1814 ** A NULL profile function means that no profiling is executes.  A non-NULL
1815 ** profile is a pointer to a function that is invoked at the conclusion of
1816 ** each SQL statement that is run.
1817 */
1818 void *sqlite3_profile(
1819   sqlite3 *db,
1820   void (*xProfile)(void*,const char*,sqlite_uint64),
1821   void *pArg
1822 ){
1823   void *pOld;
1824 
1825 #ifdef SQLITE_ENABLE_API_ARMOR
1826   if( !sqlite3SafetyCheckOk(db) ){
1827     (void)SQLITE_MISUSE_BKPT;
1828     return 0;
1829   }
1830 #endif
1831   sqlite3_mutex_enter(db->mutex);
1832   pOld = db->pProfileArg;
1833   db->xProfile = xProfile;
1834   db->pProfileArg = pArg;
1835   sqlite3_mutex_leave(db->mutex);
1836   return pOld;
1837 }
1838 #endif /* SQLITE_OMIT_TRACE */
1839 
1840 /*
1841 ** Register a function to be invoked when a transaction commits.
1842 ** If the invoked function returns non-zero, then the commit becomes a
1843 ** rollback.
1844 */
1845 void *sqlite3_commit_hook(
1846   sqlite3 *db,              /* Attach the hook to this database */
1847   int (*xCallback)(void*),  /* Function to invoke on each commit */
1848   void *pArg                /* Argument to the function */
1849 ){
1850   void *pOld;
1851 
1852 #ifdef SQLITE_ENABLE_API_ARMOR
1853   if( !sqlite3SafetyCheckOk(db) ){
1854     (void)SQLITE_MISUSE_BKPT;
1855     return 0;
1856   }
1857 #endif
1858   sqlite3_mutex_enter(db->mutex);
1859   pOld = db->pCommitArg;
1860   db->xCommitCallback = xCallback;
1861   db->pCommitArg = pArg;
1862   sqlite3_mutex_leave(db->mutex);
1863   return pOld;
1864 }
1865 
1866 /*
1867 ** Register a callback to be invoked each time a row is updated,
1868 ** inserted or deleted using this database connection.
1869 */
1870 void *sqlite3_update_hook(
1871   sqlite3 *db,              /* Attach the hook to this database */
1872   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1873   void *pArg                /* Argument to the function */
1874 ){
1875   void *pRet;
1876 
1877 #ifdef SQLITE_ENABLE_API_ARMOR
1878   if( !sqlite3SafetyCheckOk(db) ){
1879     (void)SQLITE_MISUSE_BKPT;
1880     return 0;
1881   }
1882 #endif
1883   sqlite3_mutex_enter(db->mutex);
1884   pRet = db->pUpdateArg;
1885   db->xUpdateCallback = xCallback;
1886   db->pUpdateArg = pArg;
1887   sqlite3_mutex_leave(db->mutex);
1888   return pRet;
1889 }
1890 
1891 /*
1892 ** Register a callback to be invoked each time a transaction is rolled
1893 ** back by this database connection.
1894 */
1895 void *sqlite3_rollback_hook(
1896   sqlite3 *db,              /* Attach the hook to this database */
1897   void (*xCallback)(void*), /* Callback function */
1898   void *pArg                /* Argument to the function */
1899 ){
1900   void *pRet;
1901 
1902 #ifdef SQLITE_ENABLE_API_ARMOR
1903   if( !sqlite3SafetyCheckOk(db) ){
1904     (void)SQLITE_MISUSE_BKPT;
1905     return 0;
1906   }
1907 #endif
1908   sqlite3_mutex_enter(db->mutex);
1909   pRet = db->pRollbackArg;
1910   db->xRollbackCallback = xCallback;
1911   db->pRollbackArg = pArg;
1912   sqlite3_mutex_leave(db->mutex);
1913   return pRet;
1914 }
1915 
1916 #ifndef SQLITE_OMIT_WAL
1917 /*
1918 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
1919 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
1920 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
1921 ** wal_autocheckpoint()).
1922 */
1923 int sqlite3WalDefaultHook(
1924   void *pClientData,     /* Argument */
1925   sqlite3 *db,           /* Connection */
1926   const char *zDb,       /* Database */
1927   int nFrame             /* Size of WAL */
1928 ){
1929   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
1930     sqlite3BeginBenignMalloc();
1931     sqlite3_wal_checkpoint(db, zDb);
1932     sqlite3EndBenignMalloc();
1933   }
1934   return SQLITE_OK;
1935 }
1936 #endif /* SQLITE_OMIT_WAL */
1937 
1938 /*
1939 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
1940 ** a database after committing a transaction if there are nFrame or
1941 ** more frames in the log file. Passing zero or a negative value as the
1942 ** nFrame parameter disables automatic checkpoints entirely.
1943 **
1944 ** The callback registered by this function replaces any existing callback
1945 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
1946 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
1947 ** configured by this function.
1948 */
1949 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
1950 #ifdef SQLITE_OMIT_WAL
1951   UNUSED_PARAMETER(db);
1952   UNUSED_PARAMETER(nFrame);
1953 #else
1954 #ifdef SQLITE_ENABLE_API_ARMOR
1955   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1956 #endif
1957   if( nFrame>0 ){
1958     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
1959   }else{
1960     sqlite3_wal_hook(db, 0, 0);
1961   }
1962 #endif
1963   return SQLITE_OK;
1964 }
1965 
1966 /*
1967 ** Register a callback to be invoked each time a transaction is written
1968 ** into the write-ahead-log by this database connection.
1969 */
1970 void *sqlite3_wal_hook(
1971   sqlite3 *db,                    /* Attach the hook to this db handle */
1972   int(*xCallback)(void *, sqlite3*, const char*, int),
1973   void *pArg                      /* First argument passed to xCallback() */
1974 ){
1975 #ifndef SQLITE_OMIT_WAL
1976   void *pRet;
1977 #ifdef SQLITE_ENABLE_API_ARMOR
1978   if( !sqlite3SafetyCheckOk(db) ){
1979     (void)SQLITE_MISUSE_BKPT;
1980     return 0;
1981   }
1982 #endif
1983   sqlite3_mutex_enter(db->mutex);
1984   pRet = db->pWalArg;
1985   db->xWalCallback = xCallback;
1986   db->pWalArg = pArg;
1987   sqlite3_mutex_leave(db->mutex);
1988   return pRet;
1989 #else
1990   return 0;
1991 #endif
1992 }
1993 
1994 /*
1995 ** Checkpoint database zDb.
1996 */
1997 int sqlite3_wal_checkpoint_v2(
1998   sqlite3 *db,                    /* Database handle */
1999   const char *zDb,                /* Name of attached database (or NULL) */
2000   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2001   int *pnLog,                     /* OUT: Size of WAL log in frames */
2002   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2003 ){
2004 #ifdef SQLITE_OMIT_WAL
2005   return SQLITE_OK;
2006 #else
2007   int rc;                         /* Return code */
2008   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2009 
2010 #ifdef SQLITE_ENABLE_API_ARMOR
2011   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2012 #endif
2013 
2014   /* Initialize the output variables to -1 in case an error occurs. */
2015   if( pnLog ) *pnLog = -1;
2016   if( pnCkpt ) *pnCkpt = -1;
2017 
2018   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2019   assert( SQLITE_CHECKPOINT_FULL==1 );
2020   assert( SQLITE_CHECKPOINT_RESTART==2 );
2021   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2022   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2023     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2024     ** mode: */
2025     return SQLITE_MISUSE;
2026   }
2027 
2028   sqlite3_mutex_enter(db->mutex);
2029   if( zDb && zDb[0] ){
2030     iDb = sqlite3FindDbName(db, zDb);
2031   }
2032   if( iDb<0 ){
2033     rc = SQLITE_ERROR;
2034     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2035   }else{
2036     db->busyHandler.nBusy = 0;
2037     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2038     sqlite3Error(db, rc);
2039   }
2040   rc = sqlite3ApiExit(db, rc);
2041   sqlite3_mutex_leave(db->mutex);
2042   return rc;
2043 #endif
2044 }
2045 
2046 
2047 /*
2048 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2049 ** to contains a zero-length string, all attached databases are
2050 ** checkpointed.
2051 */
2052 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2053   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2054   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2055   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2056 }
2057 
2058 #ifndef SQLITE_OMIT_WAL
2059 /*
2060 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2061 ** not currently open in WAL mode.
2062 **
2063 ** If a transaction is open on the database being checkpointed, this
2064 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2065 ** an error occurs while running the checkpoint, an SQLite error code is
2066 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2067 **
2068 ** The mutex on database handle db should be held by the caller. The mutex
2069 ** associated with the specific b-tree being checkpointed is taken by
2070 ** this function while the checkpoint is running.
2071 **
2072 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2073 ** checkpointed. If an error is encountered it is returned immediately -
2074 ** no attempt is made to checkpoint any remaining databases.
2075 **
2076 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2077 */
2078 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2079   int rc = SQLITE_OK;             /* Return code */
2080   int i;                          /* Used to iterate through attached dbs */
2081   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2082 
2083   assert( sqlite3_mutex_held(db->mutex) );
2084   assert( !pnLog || *pnLog==-1 );
2085   assert( !pnCkpt || *pnCkpt==-1 );
2086 
2087   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2088     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2089       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2090       pnLog = 0;
2091       pnCkpt = 0;
2092       if( rc==SQLITE_BUSY ){
2093         bBusy = 1;
2094         rc = SQLITE_OK;
2095       }
2096     }
2097   }
2098 
2099   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2100 }
2101 #endif /* SQLITE_OMIT_WAL */
2102 
2103 /*
2104 ** This function returns true if main-memory should be used instead of
2105 ** a temporary file for transient pager files and statement journals.
2106 ** The value returned depends on the value of db->temp_store (runtime
2107 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2108 ** following table describes the relationship between these two values
2109 ** and this functions return value.
2110 **
2111 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2112 **   -----------------     --------------     ------------------------------
2113 **   0                     any                file      (return 0)
2114 **   1                     1                  file      (return 0)
2115 **   1                     2                  memory    (return 1)
2116 **   1                     0                  file      (return 0)
2117 **   2                     1                  file      (return 0)
2118 **   2                     2                  memory    (return 1)
2119 **   2                     0                  memory    (return 1)
2120 **   3                     any                memory    (return 1)
2121 */
2122 int sqlite3TempInMemory(const sqlite3 *db){
2123 #if SQLITE_TEMP_STORE==1
2124   return ( db->temp_store==2 );
2125 #endif
2126 #if SQLITE_TEMP_STORE==2
2127   return ( db->temp_store!=1 );
2128 #endif
2129 #if SQLITE_TEMP_STORE==3
2130   UNUSED_PARAMETER(db);
2131   return 1;
2132 #endif
2133 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2134   UNUSED_PARAMETER(db);
2135   return 0;
2136 #endif
2137 }
2138 
2139 /*
2140 ** Return UTF-8 encoded English language explanation of the most recent
2141 ** error.
2142 */
2143 const char *sqlite3_errmsg(sqlite3 *db){
2144   const char *z;
2145   if( !db ){
2146     return sqlite3ErrStr(SQLITE_NOMEM);
2147   }
2148   if( !sqlite3SafetyCheckSickOrOk(db) ){
2149     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2150   }
2151   sqlite3_mutex_enter(db->mutex);
2152   if( db->mallocFailed ){
2153     z = sqlite3ErrStr(SQLITE_NOMEM);
2154   }else{
2155     testcase( db->pErr==0 );
2156     z = (char*)sqlite3_value_text(db->pErr);
2157     assert( !db->mallocFailed );
2158     if( z==0 ){
2159       z = sqlite3ErrStr(db->errCode);
2160     }
2161   }
2162   sqlite3_mutex_leave(db->mutex);
2163   return z;
2164 }
2165 
2166 #ifndef SQLITE_OMIT_UTF16
2167 /*
2168 ** Return UTF-16 encoded English language explanation of the most recent
2169 ** error.
2170 */
2171 const void *sqlite3_errmsg16(sqlite3 *db){
2172   static const u16 outOfMem[] = {
2173     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2174   };
2175   static const u16 misuse[] = {
2176     'l', 'i', 'b', 'r', 'a', 'r', 'y', ' ',
2177     'r', 'o', 'u', 't', 'i', 'n', 'e', ' ',
2178     'c', 'a', 'l', 'l', 'e', 'd', ' ',
2179     'o', 'u', 't', ' ',
2180     'o', 'f', ' ',
2181     's', 'e', 'q', 'u', 'e', 'n', 'c', 'e', 0
2182   };
2183 
2184   const void *z;
2185   if( !db ){
2186     return (void *)outOfMem;
2187   }
2188   if( !sqlite3SafetyCheckSickOrOk(db) ){
2189     return (void *)misuse;
2190   }
2191   sqlite3_mutex_enter(db->mutex);
2192   if( db->mallocFailed ){
2193     z = (void *)outOfMem;
2194   }else{
2195     z = sqlite3_value_text16(db->pErr);
2196     if( z==0 ){
2197       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2198       z = sqlite3_value_text16(db->pErr);
2199     }
2200     /* A malloc() may have failed within the call to sqlite3_value_text16()
2201     ** above. If this is the case, then the db->mallocFailed flag needs to
2202     ** be cleared before returning. Do this directly, instead of via
2203     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2204     */
2205     db->mallocFailed = 0;
2206   }
2207   sqlite3_mutex_leave(db->mutex);
2208   return z;
2209 }
2210 #endif /* SQLITE_OMIT_UTF16 */
2211 
2212 /*
2213 ** Return the most recent error code generated by an SQLite routine. If NULL is
2214 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2215 */
2216 int sqlite3_errcode(sqlite3 *db){
2217   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2218     return SQLITE_MISUSE_BKPT;
2219   }
2220   if( !db || db->mallocFailed ){
2221     return SQLITE_NOMEM;
2222   }
2223   return db->errCode & db->errMask;
2224 }
2225 int sqlite3_extended_errcode(sqlite3 *db){
2226   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2227     return SQLITE_MISUSE_BKPT;
2228   }
2229   if( !db || db->mallocFailed ){
2230     return SQLITE_NOMEM;
2231   }
2232   return db->errCode;
2233 }
2234 
2235 /*
2236 ** Return a string that describes the kind of error specified in the
2237 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2238 ** function.
2239 */
2240 const char *sqlite3_errstr(int rc){
2241   return sqlite3ErrStr(rc);
2242 }
2243 
2244 /*
2245 ** Create a new collating function for database "db".  The name is zName
2246 ** and the encoding is enc.
2247 */
2248 static int createCollation(
2249   sqlite3* db,
2250   const char *zName,
2251   u8 enc,
2252   void* pCtx,
2253   int(*xCompare)(void*,int,const void*,int,const void*),
2254   void(*xDel)(void*)
2255 ){
2256   CollSeq *pColl;
2257   int enc2;
2258 
2259   assert( sqlite3_mutex_held(db->mutex) );
2260 
2261   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2262   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2263   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2264   */
2265   enc2 = enc;
2266   testcase( enc2==SQLITE_UTF16 );
2267   testcase( enc2==SQLITE_UTF16_ALIGNED );
2268   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2269     enc2 = SQLITE_UTF16NATIVE;
2270   }
2271   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2272     return SQLITE_MISUSE_BKPT;
2273   }
2274 
2275   /* Check if this call is removing or replacing an existing collation
2276   ** sequence. If so, and there are active VMs, return busy. If there
2277   ** are no active VMs, invalidate any pre-compiled statements.
2278   */
2279   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2280   if( pColl && pColl->xCmp ){
2281     if( db->nVdbeActive ){
2282       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2283         "unable to delete/modify collation sequence due to active statements");
2284       return SQLITE_BUSY;
2285     }
2286     sqlite3ExpirePreparedStatements(db);
2287 
2288     /* If collation sequence pColl was created directly by a call to
2289     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2290     ** then any copies made by synthCollSeq() need to be invalidated.
2291     ** Also, collation destructor - CollSeq.xDel() - function may need
2292     ** to be called.
2293     */
2294     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2295       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2296       int j;
2297       for(j=0; j<3; j++){
2298         CollSeq *p = &aColl[j];
2299         if( p->enc==pColl->enc ){
2300           if( p->xDel ){
2301             p->xDel(p->pUser);
2302           }
2303           p->xCmp = 0;
2304         }
2305       }
2306     }
2307   }
2308 
2309   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2310   if( pColl==0 ) return SQLITE_NOMEM;
2311   pColl->xCmp = xCompare;
2312   pColl->pUser = pCtx;
2313   pColl->xDel = xDel;
2314   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2315   sqlite3Error(db, SQLITE_OK);
2316   return SQLITE_OK;
2317 }
2318 
2319 
2320 /*
2321 ** This array defines hard upper bounds on limit values.  The
2322 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2323 ** #defines in sqlite3.h.
2324 */
2325 static const int aHardLimit[] = {
2326   SQLITE_MAX_LENGTH,
2327   SQLITE_MAX_SQL_LENGTH,
2328   SQLITE_MAX_COLUMN,
2329   SQLITE_MAX_EXPR_DEPTH,
2330   SQLITE_MAX_COMPOUND_SELECT,
2331   SQLITE_MAX_VDBE_OP,
2332   SQLITE_MAX_FUNCTION_ARG,
2333   SQLITE_MAX_ATTACHED,
2334   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2335   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2336   SQLITE_MAX_TRIGGER_DEPTH,
2337   SQLITE_MAX_WORKER_THREADS,
2338 };
2339 
2340 /*
2341 ** Make sure the hard limits are set to reasonable values
2342 */
2343 #if SQLITE_MAX_LENGTH<100
2344 # error SQLITE_MAX_LENGTH must be at least 100
2345 #endif
2346 #if SQLITE_MAX_SQL_LENGTH<100
2347 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2348 #endif
2349 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2350 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2351 #endif
2352 #if SQLITE_MAX_COMPOUND_SELECT<2
2353 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2354 #endif
2355 #if SQLITE_MAX_VDBE_OP<40
2356 # error SQLITE_MAX_VDBE_OP must be at least 40
2357 #endif
2358 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
2359 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
2360 #endif
2361 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2362 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2363 #endif
2364 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2365 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2366 #endif
2367 #if SQLITE_MAX_COLUMN>32767
2368 # error SQLITE_MAX_COLUMN must not exceed 32767
2369 #endif
2370 #if SQLITE_MAX_TRIGGER_DEPTH<1
2371 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2372 #endif
2373 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2374 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2375 #endif
2376 
2377 
2378 /*
2379 ** Change the value of a limit.  Report the old value.
2380 ** If an invalid limit index is supplied, report -1.
2381 ** Make no changes but still report the old value if the
2382 ** new limit is negative.
2383 **
2384 ** A new lower limit does not shrink existing constructs.
2385 ** It merely prevents new constructs that exceed the limit
2386 ** from forming.
2387 */
2388 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2389   int oldLimit;
2390 
2391 #ifdef SQLITE_ENABLE_API_ARMOR
2392   if( !sqlite3SafetyCheckOk(db) ){
2393     (void)SQLITE_MISUSE_BKPT;
2394     return -1;
2395   }
2396 #endif
2397 
2398   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2399   ** there is a hard upper bound set at compile-time by a C preprocessor
2400   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2401   ** "_MAX_".)
2402   */
2403   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2404   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2405   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2406   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2407   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2408   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2409   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2410   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2411   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2412                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2413   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2414   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2415   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2416   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2417 
2418 
2419   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2420     return -1;
2421   }
2422   oldLimit = db->aLimit[limitId];
2423   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2424     if( newLimit>aHardLimit[limitId] ){
2425       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2426     }
2427     db->aLimit[limitId] = newLimit;
2428   }
2429   return oldLimit;                     /* IMP: R-53341-35419 */
2430 }
2431 
2432 /*
2433 ** This function is used to parse both URIs and non-URI filenames passed by the
2434 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2435 ** URIs specified as part of ATTACH statements.
2436 **
2437 ** The first argument to this function is the name of the VFS to use (or
2438 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2439 ** query parameter. The second argument contains the URI (or non-URI filename)
2440 ** itself. When this function is called the *pFlags variable should contain
2441 ** the default flags to open the database handle with. The value stored in
2442 ** *pFlags may be updated before returning if the URI filename contains
2443 ** "cache=xxx" or "mode=xxx" query parameters.
2444 **
2445 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2446 ** the VFS that should be used to open the database file. *pzFile is set to
2447 ** point to a buffer containing the name of the file to open. It is the
2448 ** responsibility of the caller to eventually call sqlite3_free() to release
2449 ** this buffer.
2450 **
2451 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2452 ** may be set to point to a buffer containing an English language error
2453 ** message. It is the responsibility of the caller to eventually release
2454 ** this buffer by calling sqlite3_free().
2455 */
2456 int sqlite3ParseUri(
2457   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2458   const char *zUri,               /* Nul-terminated URI to parse */
2459   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2460   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2461   char **pzFile,                  /* OUT: Filename component of URI */
2462   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2463 ){
2464   int rc = SQLITE_OK;
2465   unsigned int flags = *pFlags;
2466   const char *zVfs = zDefaultVfs;
2467   char *zFile;
2468   char c;
2469   int nUri = sqlite3Strlen30(zUri);
2470 
2471   assert( *pzErrMsg==0 );
2472 
2473   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2474             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2475    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2476   ){
2477     char *zOpt;
2478     int eState;                   /* Parser state when parsing URI */
2479     int iIn;                      /* Input character index */
2480     int iOut = 0;                 /* Output character index */
2481     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2482 
2483     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2484     ** method that there may be extra parameters following the file-name.  */
2485     flags |= SQLITE_OPEN_URI;
2486 
2487     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2488     zFile = sqlite3_malloc64(nByte);
2489     if( !zFile ) return SQLITE_NOMEM;
2490 
2491     iIn = 5;
2492 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2493     if( strncmp(zUri+5, "///", 3)==0 ){
2494       iIn = 7;
2495       /* The following condition causes URIs with five leading / characters
2496       ** like file://///host/path to be converted into UNCs like //host/path.
2497       ** The correct URI for that UNC has only two or four leading / characters
2498       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2499       ** common error, we are told, so we handle it as a special case. */
2500       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2501     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2502       iIn = 16;
2503     }
2504 #else
2505     /* Discard the scheme and authority segments of the URI. */
2506     if( zUri[5]=='/' && zUri[6]=='/' ){
2507       iIn = 7;
2508       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2509       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2510         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2511             iIn-7, &zUri[7]);
2512         rc = SQLITE_ERROR;
2513         goto parse_uri_out;
2514       }
2515     }
2516 #endif
2517 
2518     /* Copy the filename and any query parameters into the zFile buffer.
2519     ** Decode %HH escape codes along the way.
2520     **
2521     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2522     ** on the parsing context. As follows:
2523     **
2524     **   0: Parsing file-name.
2525     **   1: Parsing name section of a name=value query parameter.
2526     **   2: Parsing value section of a name=value query parameter.
2527     */
2528     eState = 0;
2529     while( (c = zUri[iIn])!=0 && c!='#' ){
2530       iIn++;
2531       if( c=='%'
2532        && sqlite3Isxdigit(zUri[iIn])
2533        && sqlite3Isxdigit(zUri[iIn+1])
2534       ){
2535         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2536         octet += sqlite3HexToInt(zUri[iIn++]);
2537 
2538         assert( octet>=0 && octet<256 );
2539         if( octet==0 ){
2540           /* This branch is taken when "%00" appears within the URI. In this
2541           ** case we ignore all text in the remainder of the path, name or
2542           ** value currently being parsed. So ignore the current character
2543           ** and skip to the next "?", "=" or "&", as appropriate. */
2544           while( (c = zUri[iIn])!=0 && c!='#'
2545               && (eState!=0 || c!='?')
2546               && (eState!=1 || (c!='=' && c!='&'))
2547               && (eState!=2 || c!='&')
2548           ){
2549             iIn++;
2550           }
2551           continue;
2552         }
2553         c = octet;
2554       }else if( eState==1 && (c=='&' || c=='=') ){
2555         if( zFile[iOut-1]==0 ){
2556           /* An empty option name. Ignore this option altogether. */
2557           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2558           continue;
2559         }
2560         if( c=='&' ){
2561           zFile[iOut++] = '\0';
2562         }else{
2563           eState = 2;
2564         }
2565         c = 0;
2566       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2567         c = 0;
2568         eState = 1;
2569       }
2570       zFile[iOut++] = c;
2571     }
2572     if( eState==1 ) zFile[iOut++] = '\0';
2573     zFile[iOut++] = '\0';
2574     zFile[iOut++] = '\0';
2575 
2576     /* Check if there were any options specified that should be interpreted
2577     ** here. Options that are interpreted here include "vfs" and those that
2578     ** correspond to flags that may be passed to the sqlite3_open_v2()
2579     ** method. */
2580     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2581     while( zOpt[0] ){
2582       int nOpt = sqlite3Strlen30(zOpt);
2583       char *zVal = &zOpt[nOpt+1];
2584       int nVal = sqlite3Strlen30(zVal);
2585 
2586       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2587         zVfs = zVal;
2588       }else{
2589         struct OpenMode {
2590           const char *z;
2591           int mode;
2592         } *aMode = 0;
2593         char *zModeType = 0;
2594         int mask = 0;
2595         int limit = 0;
2596 
2597         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2598           static struct OpenMode aCacheMode[] = {
2599             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2600             { "private", SQLITE_OPEN_PRIVATECACHE },
2601             { 0, 0 }
2602           };
2603 
2604           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2605           aMode = aCacheMode;
2606           limit = mask;
2607           zModeType = "cache";
2608         }
2609         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2610           static struct OpenMode aOpenMode[] = {
2611             { "ro",  SQLITE_OPEN_READONLY },
2612             { "rw",  SQLITE_OPEN_READWRITE },
2613             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2614             { "memory", SQLITE_OPEN_MEMORY },
2615             { 0, 0 }
2616           };
2617 
2618           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2619                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2620           aMode = aOpenMode;
2621           limit = mask & flags;
2622           zModeType = "access";
2623         }
2624 
2625         if( aMode ){
2626           int i;
2627           int mode = 0;
2628           for(i=0; aMode[i].z; i++){
2629             const char *z = aMode[i].z;
2630             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2631               mode = aMode[i].mode;
2632               break;
2633             }
2634           }
2635           if( mode==0 ){
2636             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2637             rc = SQLITE_ERROR;
2638             goto parse_uri_out;
2639           }
2640           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2641             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2642                                         zModeType, zVal);
2643             rc = SQLITE_PERM;
2644             goto parse_uri_out;
2645           }
2646           flags = (flags & ~mask) | mode;
2647         }
2648       }
2649 
2650       zOpt = &zVal[nVal+1];
2651     }
2652 
2653   }else{
2654     zFile = sqlite3_malloc64(nUri+2);
2655     if( !zFile ) return SQLITE_NOMEM;
2656     memcpy(zFile, zUri, nUri);
2657     zFile[nUri] = '\0';
2658     zFile[nUri+1] = '\0';
2659     flags &= ~SQLITE_OPEN_URI;
2660   }
2661 
2662   *ppVfs = sqlite3_vfs_find(zVfs);
2663   if( *ppVfs==0 ){
2664     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2665     rc = SQLITE_ERROR;
2666   }
2667  parse_uri_out:
2668   if( rc!=SQLITE_OK ){
2669     sqlite3_free(zFile);
2670     zFile = 0;
2671   }
2672   *pFlags = flags;
2673   *pzFile = zFile;
2674   return rc;
2675 }
2676 
2677 
2678 /*
2679 ** This routine does the work of opening a database on behalf of
2680 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2681 ** is UTF-8 encoded.
2682 */
2683 static int openDatabase(
2684   const char *zFilename, /* Database filename UTF-8 encoded */
2685   sqlite3 **ppDb,        /* OUT: Returned database handle */
2686   unsigned int flags,    /* Operational flags */
2687   const char *zVfs       /* Name of the VFS to use */
2688 ){
2689   sqlite3 *db;                    /* Store allocated handle here */
2690   int rc;                         /* Return code */
2691   int isThreadsafe;               /* True for threadsafe connections */
2692   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2693   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2694 
2695 #ifdef SQLITE_ENABLE_API_ARMOR
2696   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2697 #endif
2698   *ppDb = 0;
2699 #ifndef SQLITE_OMIT_AUTOINIT
2700   rc = sqlite3_initialize();
2701   if( rc ) return rc;
2702 #endif
2703 
2704   /* Only allow sensible combinations of bits in the flags argument.
2705   ** Throw an error if any non-sense combination is used.  If we
2706   ** do not block illegal combinations here, it could trigger
2707   ** assert() statements in deeper layers.  Sensible combinations
2708   ** are:
2709   **
2710   **  1:  SQLITE_OPEN_READONLY
2711   **  2:  SQLITE_OPEN_READWRITE
2712   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2713   */
2714   assert( SQLITE_OPEN_READONLY  == 0x01 );
2715   assert( SQLITE_OPEN_READWRITE == 0x02 );
2716   assert( SQLITE_OPEN_CREATE    == 0x04 );
2717   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2718   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2719   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2720   if( ((1<<(flags&7)) & 0x46)==0 ){
2721     return SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2722   }
2723 
2724   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2725     isThreadsafe = 0;
2726   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2727     isThreadsafe = 0;
2728   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2729     isThreadsafe = 1;
2730   }else{
2731     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2732   }
2733   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2734     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2735   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2736     flags |= SQLITE_OPEN_SHAREDCACHE;
2737   }
2738 
2739   /* Remove harmful bits from the flags parameter
2740   **
2741   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2742   ** dealt with in the previous code block.  Besides these, the only
2743   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2744   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2745   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2746   ** off all other flags.
2747   */
2748   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2749                SQLITE_OPEN_EXCLUSIVE |
2750                SQLITE_OPEN_MAIN_DB |
2751                SQLITE_OPEN_TEMP_DB |
2752                SQLITE_OPEN_TRANSIENT_DB |
2753                SQLITE_OPEN_MAIN_JOURNAL |
2754                SQLITE_OPEN_TEMP_JOURNAL |
2755                SQLITE_OPEN_SUBJOURNAL |
2756                SQLITE_OPEN_MASTER_JOURNAL |
2757                SQLITE_OPEN_NOMUTEX |
2758                SQLITE_OPEN_FULLMUTEX |
2759                SQLITE_OPEN_WAL
2760              );
2761 
2762   /* Allocate the sqlite data structure */
2763   db = sqlite3MallocZero( sizeof(sqlite3) );
2764   if( db==0 ) goto opendb_out;
2765   if( isThreadsafe ){
2766     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2767     if( db->mutex==0 ){
2768       sqlite3_free(db);
2769       db = 0;
2770       goto opendb_out;
2771     }
2772   }
2773   sqlite3_mutex_enter(db->mutex);
2774   db->errMask = 0xff;
2775   db->nDb = 2;
2776   db->magic = SQLITE_MAGIC_BUSY;
2777   db->aDb = db->aDbStatic;
2778 
2779   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2780   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2781   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2782   db->autoCommit = 1;
2783   db->nextAutovac = -1;
2784   db->szMmap = sqlite3GlobalConfig.szMmap;
2785   db->nextPagesize = 0;
2786   db->nMaxSorterMmap = 0x7FFFFFFF;
2787   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2788 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2789                  | SQLITE_AutoIndex
2790 #endif
2791 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2792                  | SQLITE_CkptFullFSync
2793 #endif
2794 #if SQLITE_DEFAULT_FILE_FORMAT<4
2795                  | SQLITE_LegacyFileFmt
2796 #endif
2797 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2798                  | SQLITE_LoadExtension
2799 #endif
2800 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2801                  | SQLITE_RecTriggers
2802 #endif
2803 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2804                  | SQLITE_ForeignKeys
2805 #endif
2806 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2807                  | SQLITE_ReverseOrder
2808 #endif
2809 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2810                  | SQLITE_CellSizeCk
2811 #endif
2812       ;
2813   sqlite3HashInit(&db->aCollSeq);
2814 #ifndef SQLITE_OMIT_VIRTUALTABLE
2815   sqlite3HashInit(&db->aModule);
2816 #endif
2817 
2818   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2819   ** and UTF-16, so add a version for each to avoid any unnecessary
2820   ** conversions. The only error that can occur here is a malloc() failure.
2821   **
2822   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2823   ** functions:
2824   */
2825   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
2826   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
2827   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
2828   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2829   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2830   if( db->mallocFailed ){
2831     goto opendb_out;
2832   }
2833   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2834   ** strings is BINARY.
2835   */
2836   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
2837   assert( db->pDfltColl!=0 );
2838 
2839   /* Parse the filename/URI argument. */
2840   db->openFlags = flags;
2841   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2842   if( rc!=SQLITE_OK ){
2843     if( rc==SQLITE_NOMEM ) db->mallocFailed = 1;
2844     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2845     sqlite3_free(zErrMsg);
2846     goto opendb_out;
2847   }
2848 
2849   /* Open the backend database driver */
2850   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2851                         flags | SQLITE_OPEN_MAIN_DB);
2852   if( rc!=SQLITE_OK ){
2853     if( rc==SQLITE_IOERR_NOMEM ){
2854       rc = SQLITE_NOMEM;
2855     }
2856     sqlite3Error(db, rc);
2857     goto opendb_out;
2858   }
2859   sqlite3BtreeEnter(db->aDb[0].pBt);
2860   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2861   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2862   sqlite3BtreeLeave(db->aDb[0].pBt);
2863   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2864 
2865   /* The default safety_level for the main database is 'full'; for the temp
2866   ** database it is 'NONE'. This matches the pager layer defaults.
2867   */
2868   db->aDb[0].zName = "main";
2869   db->aDb[0].safety_level = 3;
2870   db->aDb[1].zName = "temp";
2871   db->aDb[1].safety_level = 1;
2872 
2873   db->magic = SQLITE_MAGIC_OPEN;
2874   if( db->mallocFailed ){
2875     goto opendb_out;
2876   }
2877 
2878   /* Register all built-in functions, but do not attempt to read the
2879   ** database schema yet. This is delayed until the first time the database
2880   ** is accessed.
2881   */
2882   sqlite3Error(db, SQLITE_OK);
2883   sqlite3RegisterBuiltinFunctions(db);
2884 
2885   /* Load automatic extensions - extensions that have been registered
2886   ** using the sqlite3_automatic_extension() API.
2887   */
2888   rc = sqlite3_errcode(db);
2889   if( rc==SQLITE_OK ){
2890     sqlite3AutoLoadExtensions(db);
2891     rc = sqlite3_errcode(db);
2892     if( rc!=SQLITE_OK ){
2893       goto opendb_out;
2894     }
2895   }
2896 
2897 #ifdef SQLITE_ENABLE_FTS1
2898   if( !db->mallocFailed ){
2899     extern int sqlite3Fts1Init(sqlite3*);
2900     rc = sqlite3Fts1Init(db);
2901   }
2902 #endif
2903 
2904 #ifdef SQLITE_ENABLE_FTS2
2905   if( !db->mallocFailed && rc==SQLITE_OK ){
2906     extern int sqlite3Fts2Init(sqlite3*);
2907     rc = sqlite3Fts2Init(db);
2908   }
2909 #endif
2910 
2911 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
2912   if( !db->mallocFailed && rc==SQLITE_OK ){
2913     rc = sqlite3Fts3Init(db);
2914   }
2915 #endif
2916 
2917 #ifdef SQLITE_ENABLE_FTS5
2918   if( !db->mallocFailed && rc==SQLITE_OK ){
2919     rc = sqlite3Fts5Init(db);
2920   }
2921 #endif
2922 
2923 #ifdef SQLITE_ENABLE_ICU
2924   if( !db->mallocFailed && rc==SQLITE_OK ){
2925     rc = sqlite3IcuInit(db);
2926   }
2927 #endif
2928 
2929 #ifdef SQLITE_ENABLE_RTREE
2930   if( !db->mallocFailed && rc==SQLITE_OK){
2931     rc = sqlite3RtreeInit(db);
2932   }
2933 #endif
2934 
2935 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
2936   if( !db->mallocFailed && rc==SQLITE_OK){
2937     rc = sqlite3DbstatRegister(db);
2938   }
2939 #endif
2940 
2941 #ifdef SQLITE_ENABLE_JSON1
2942   if( !db->mallocFailed && rc==SQLITE_OK){
2943     rc = sqlite3Json1Init(db);
2944   }
2945 #endif
2946 
2947   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
2948   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
2949   ** mode.  Doing nothing at all also makes NORMAL the default.
2950   */
2951 #ifdef SQLITE_DEFAULT_LOCKING_MODE
2952   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
2953   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
2954                           SQLITE_DEFAULT_LOCKING_MODE);
2955 #endif
2956 
2957   if( rc ) sqlite3Error(db, rc);
2958 
2959   /* Enable the lookaside-malloc subsystem */
2960   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
2961                         sqlite3GlobalConfig.nLookaside);
2962 
2963   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
2964 
2965 opendb_out:
2966   sqlite3_free(zOpen);
2967   if( db ){
2968     assert( db->mutex!=0 || isThreadsafe==0
2969            || sqlite3GlobalConfig.bFullMutex==0 );
2970     sqlite3_mutex_leave(db->mutex);
2971   }
2972   rc = sqlite3_errcode(db);
2973   assert( db!=0 || rc==SQLITE_NOMEM );
2974   if( rc==SQLITE_NOMEM ){
2975     sqlite3_close(db);
2976     db = 0;
2977   }else if( rc!=SQLITE_OK ){
2978     db->magic = SQLITE_MAGIC_SICK;
2979   }
2980   *ppDb = db;
2981 #ifdef SQLITE_ENABLE_SQLLOG
2982   if( sqlite3GlobalConfig.xSqllog ){
2983     /* Opening a db handle. Fourth parameter is passed 0. */
2984     void *pArg = sqlite3GlobalConfig.pSqllogArg;
2985     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
2986   }
2987 #endif
2988 #if defined(SQLITE_HAS_CODEC)
2989   if( rc==SQLITE_OK ){
2990     const char *zHexKey = sqlite3_uri_parameter(zOpen, "hexkey");
2991     if( zHexKey && zHexKey[0] ){
2992       u8 iByte;
2993       int i;
2994       char zKey[40];
2995       for(i=0, iByte=0; i<sizeof(zKey)*2 && sqlite3Isxdigit(zHexKey[i]); i++){
2996         iByte = (iByte<<4) + sqlite3HexToInt(zHexKey[i]);
2997         if( (i&1)!=0 ) zKey[i/2] = iByte;
2998       }
2999       sqlite3_key_v2(db, 0, zKey, i/2);
3000     }
3001   }
3002 #endif
3003   return rc & 0xff;
3004 }
3005 
3006 /*
3007 ** Open a new database handle.
3008 */
3009 int sqlite3_open(
3010   const char *zFilename,
3011   sqlite3 **ppDb
3012 ){
3013   return openDatabase(zFilename, ppDb,
3014                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3015 }
3016 int sqlite3_open_v2(
3017   const char *filename,   /* Database filename (UTF-8) */
3018   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3019   int flags,              /* Flags */
3020   const char *zVfs        /* Name of VFS module to use */
3021 ){
3022   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3023 }
3024 
3025 #ifndef SQLITE_OMIT_UTF16
3026 /*
3027 ** Open a new database handle.
3028 */
3029 int sqlite3_open16(
3030   const void *zFilename,
3031   sqlite3 **ppDb
3032 ){
3033   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3034   sqlite3_value *pVal;
3035   int rc;
3036 
3037 #ifdef SQLITE_ENABLE_API_ARMOR
3038   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3039 #endif
3040   *ppDb = 0;
3041 #ifndef SQLITE_OMIT_AUTOINIT
3042   rc = sqlite3_initialize();
3043   if( rc ) return rc;
3044 #endif
3045   if( zFilename==0 ) zFilename = "\000\000";
3046   pVal = sqlite3ValueNew(0);
3047   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3048   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3049   if( zFilename8 ){
3050     rc = openDatabase(zFilename8, ppDb,
3051                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3052     assert( *ppDb || rc==SQLITE_NOMEM );
3053     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3054       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3055     }
3056   }else{
3057     rc = SQLITE_NOMEM;
3058   }
3059   sqlite3ValueFree(pVal);
3060 
3061   return rc & 0xff;
3062 }
3063 #endif /* SQLITE_OMIT_UTF16 */
3064 
3065 /*
3066 ** Register a new collation sequence with the database handle db.
3067 */
3068 int sqlite3_create_collation(
3069   sqlite3* db,
3070   const char *zName,
3071   int enc,
3072   void* pCtx,
3073   int(*xCompare)(void*,int,const void*,int,const void*)
3074 ){
3075   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3076 }
3077 
3078 /*
3079 ** Register a new collation sequence with the database handle db.
3080 */
3081 int sqlite3_create_collation_v2(
3082   sqlite3* db,
3083   const char *zName,
3084   int enc,
3085   void* pCtx,
3086   int(*xCompare)(void*,int,const void*,int,const void*),
3087   void(*xDel)(void*)
3088 ){
3089   int rc;
3090 
3091 #ifdef SQLITE_ENABLE_API_ARMOR
3092   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3093 #endif
3094   sqlite3_mutex_enter(db->mutex);
3095   assert( !db->mallocFailed );
3096   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3097   rc = sqlite3ApiExit(db, rc);
3098   sqlite3_mutex_leave(db->mutex);
3099   return rc;
3100 }
3101 
3102 #ifndef SQLITE_OMIT_UTF16
3103 /*
3104 ** Register a new collation sequence with the database handle db.
3105 */
3106 int sqlite3_create_collation16(
3107   sqlite3* db,
3108   const void *zName,
3109   int enc,
3110   void* pCtx,
3111   int(*xCompare)(void*,int,const void*,int,const void*)
3112 ){
3113   int rc = SQLITE_OK;
3114   char *zName8;
3115 
3116 #ifdef SQLITE_ENABLE_API_ARMOR
3117   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3118 #endif
3119   sqlite3_mutex_enter(db->mutex);
3120   assert( !db->mallocFailed );
3121   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3122   if( zName8 ){
3123     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3124     sqlite3DbFree(db, zName8);
3125   }
3126   rc = sqlite3ApiExit(db, rc);
3127   sqlite3_mutex_leave(db->mutex);
3128   return rc;
3129 }
3130 #endif /* SQLITE_OMIT_UTF16 */
3131 
3132 /*
3133 ** Register a collation sequence factory callback with the database handle
3134 ** db. Replace any previously installed collation sequence factory.
3135 */
3136 int sqlite3_collation_needed(
3137   sqlite3 *db,
3138   void *pCollNeededArg,
3139   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3140 ){
3141 #ifdef SQLITE_ENABLE_API_ARMOR
3142   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3143 #endif
3144   sqlite3_mutex_enter(db->mutex);
3145   db->xCollNeeded = xCollNeeded;
3146   db->xCollNeeded16 = 0;
3147   db->pCollNeededArg = pCollNeededArg;
3148   sqlite3_mutex_leave(db->mutex);
3149   return SQLITE_OK;
3150 }
3151 
3152 #ifndef SQLITE_OMIT_UTF16
3153 /*
3154 ** Register a collation sequence factory callback with the database handle
3155 ** db. Replace any previously installed collation sequence factory.
3156 */
3157 int sqlite3_collation_needed16(
3158   sqlite3 *db,
3159   void *pCollNeededArg,
3160   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3161 ){
3162 #ifdef SQLITE_ENABLE_API_ARMOR
3163   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3164 #endif
3165   sqlite3_mutex_enter(db->mutex);
3166   db->xCollNeeded = 0;
3167   db->xCollNeeded16 = xCollNeeded16;
3168   db->pCollNeededArg = pCollNeededArg;
3169   sqlite3_mutex_leave(db->mutex);
3170   return SQLITE_OK;
3171 }
3172 #endif /* SQLITE_OMIT_UTF16 */
3173 
3174 #ifndef SQLITE_OMIT_DEPRECATED
3175 /*
3176 ** This function is now an anachronism. It used to be used to recover from a
3177 ** malloc() failure, but SQLite now does this automatically.
3178 */
3179 int sqlite3_global_recover(void){
3180   return SQLITE_OK;
3181 }
3182 #endif
3183 
3184 /*
3185 ** Test to see whether or not the database connection is in autocommit
3186 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3187 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3188 ** by the next COMMIT or ROLLBACK.
3189 */
3190 int sqlite3_get_autocommit(sqlite3 *db){
3191 #ifdef SQLITE_ENABLE_API_ARMOR
3192   if( !sqlite3SafetyCheckOk(db) ){
3193     (void)SQLITE_MISUSE_BKPT;
3194     return 0;
3195   }
3196 #endif
3197   return db->autoCommit;
3198 }
3199 
3200 /*
3201 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3202 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_IOERR and possibly other error
3203 ** constants.  They serve two purposes:
3204 **
3205 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3206 **       to detect when version error conditions occurs.
3207 **
3208 **   2.  Invoke sqlite3_log() to provide the source code location where
3209 **       a low-level error is first detected.
3210 */
3211 int sqlite3CorruptError(int lineno){
3212   testcase( sqlite3GlobalConfig.xLog!=0 );
3213   sqlite3_log(SQLITE_CORRUPT,
3214               "database corruption at line %d of [%.10s]",
3215               lineno, 20+sqlite3_sourceid());
3216   return SQLITE_CORRUPT;
3217 }
3218 int sqlite3MisuseError(int lineno){
3219   testcase( sqlite3GlobalConfig.xLog!=0 );
3220   sqlite3_log(SQLITE_MISUSE,
3221               "misuse at line %d of [%.10s]",
3222               lineno, 20+sqlite3_sourceid());
3223   return SQLITE_MISUSE;
3224 }
3225 int sqlite3CantopenError(int lineno){
3226   testcase( sqlite3GlobalConfig.xLog!=0 );
3227   sqlite3_log(SQLITE_CANTOPEN,
3228               "cannot open file at line %d of [%.10s]",
3229               lineno, 20+sqlite3_sourceid());
3230   return SQLITE_CANTOPEN;
3231 }
3232 
3233 
3234 #ifndef SQLITE_OMIT_DEPRECATED
3235 /*
3236 ** This is a convenience routine that makes sure that all thread-specific
3237 ** data for this thread has been deallocated.
3238 **
3239 ** SQLite no longer uses thread-specific data so this routine is now a
3240 ** no-op.  It is retained for historical compatibility.
3241 */
3242 void sqlite3_thread_cleanup(void){
3243 }
3244 #endif
3245 
3246 /*
3247 ** Return meta information about a specific column of a database table.
3248 ** See comment in sqlite3.h (sqlite.h.in) for details.
3249 */
3250 int sqlite3_table_column_metadata(
3251   sqlite3 *db,                /* Connection handle */
3252   const char *zDbName,        /* Database name or NULL */
3253   const char *zTableName,     /* Table name */
3254   const char *zColumnName,    /* Column name */
3255   char const **pzDataType,    /* OUTPUT: Declared data type */
3256   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3257   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3258   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3259   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3260 ){
3261   int rc;
3262   char *zErrMsg = 0;
3263   Table *pTab = 0;
3264   Column *pCol = 0;
3265   int iCol = 0;
3266   char const *zDataType = 0;
3267   char const *zCollSeq = 0;
3268   int notnull = 0;
3269   int primarykey = 0;
3270   int autoinc = 0;
3271 
3272 
3273 #ifdef SQLITE_ENABLE_API_ARMOR
3274   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3275     return SQLITE_MISUSE_BKPT;
3276   }
3277 #endif
3278 
3279   /* Ensure the database schema has been loaded */
3280   sqlite3_mutex_enter(db->mutex);
3281   sqlite3BtreeEnterAll(db);
3282   rc = sqlite3Init(db, &zErrMsg);
3283   if( SQLITE_OK!=rc ){
3284     goto error_out;
3285   }
3286 
3287   /* Locate the table in question */
3288   pTab = sqlite3FindTable(db, zTableName, zDbName);
3289   if( !pTab || pTab->pSelect ){
3290     pTab = 0;
3291     goto error_out;
3292   }
3293 
3294   /* Find the column for which info is requested */
3295   if( zColumnName==0 ){
3296     /* Query for existance of table only */
3297   }else{
3298     for(iCol=0; iCol<pTab->nCol; iCol++){
3299       pCol = &pTab->aCol[iCol];
3300       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3301         break;
3302       }
3303     }
3304     if( iCol==pTab->nCol ){
3305       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3306         iCol = pTab->iPKey;
3307         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3308       }else{
3309         pTab = 0;
3310         goto error_out;
3311       }
3312     }
3313   }
3314 
3315   /* The following block stores the meta information that will be returned
3316   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3317   ** and autoinc. At this point there are two possibilities:
3318   **
3319   **     1. The specified column name was rowid", "oid" or "_rowid_"
3320   **        and there is no explicitly declared IPK column.
3321   **
3322   **     2. The table is not a view and the column name identified an
3323   **        explicitly declared column. Copy meta information from *pCol.
3324   */
3325   if( pCol ){
3326     zDataType = pCol->zType;
3327     zCollSeq = pCol->zColl;
3328     notnull = pCol->notNull!=0;
3329     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3330     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3331   }else{
3332     zDataType = "INTEGER";
3333     primarykey = 1;
3334   }
3335   if( !zCollSeq ){
3336     zCollSeq = "BINARY";
3337   }
3338 
3339 error_out:
3340   sqlite3BtreeLeaveAll(db);
3341 
3342   /* Whether the function call succeeded or failed, set the output parameters
3343   ** to whatever their local counterparts contain. If an error did occur,
3344   ** this has the effect of zeroing all output parameters.
3345   */
3346   if( pzDataType ) *pzDataType = zDataType;
3347   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3348   if( pNotNull ) *pNotNull = notnull;
3349   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3350   if( pAutoinc ) *pAutoinc = autoinc;
3351 
3352   if( SQLITE_OK==rc && !pTab ){
3353     sqlite3DbFree(db, zErrMsg);
3354     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3355         zColumnName);
3356     rc = SQLITE_ERROR;
3357   }
3358   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3359   sqlite3DbFree(db, zErrMsg);
3360   rc = sqlite3ApiExit(db, rc);
3361   sqlite3_mutex_leave(db->mutex);
3362   return rc;
3363 }
3364 
3365 /*
3366 ** Sleep for a little while.  Return the amount of time slept.
3367 */
3368 int sqlite3_sleep(int ms){
3369   sqlite3_vfs *pVfs;
3370   int rc;
3371   pVfs = sqlite3_vfs_find(0);
3372   if( pVfs==0 ) return 0;
3373 
3374   /* This function works in milliseconds, but the underlying OsSleep()
3375   ** API uses microseconds. Hence the 1000's.
3376   */
3377   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3378   return rc;
3379 }
3380 
3381 /*
3382 ** Enable or disable the extended result codes.
3383 */
3384 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3385 #ifdef SQLITE_ENABLE_API_ARMOR
3386   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3387 #endif
3388   sqlite3_mutex_enter(db->mutex);
3389   db->errMask = onoff ? 0xffffffff : 0xff;
3390   sqlite3_mutex_leave(db->mutex);
3391   return SQLITE_OK;
3392 }
3393 
3394 /*
3395 ** Invoke the xFileControl method on a particular database.
3396 */
3397 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3398   int rc = SQLITE_ERROR;
3399   Btree *pBtree;
3400 
3401 #ifdef SQLITE_ENABLE_API_ARMOR
3402   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3403 #endif
3404   sqlite3_mutex_enter(db->mutex);
3405   pBtree = sqlite3DbNameToBtree(db, zDbName);
3406   if( pBtree ){
3407     Pager *pPager;
3408     sqlite3_file *fd;
3409     sqlite3BtreeEnter(pBtree);
3410     pPager = sqlite3BtreePager(pBtree);
3411     assert( pPager!=0 );
3412     fd = sqlite3PagerFile(pPager);
3413     assert( fd!=0 );
3414     if( op==SQLITE_FCNTL_FILE_POINTER ){
3415       *(sqlite3_file**)pArg = fd;
3416       rc = SQLITE_OK;
3417     }else if( fd->pMethods ){
3418       rc = sqlite3OsFileControl(fd, op, pArg);
3419     }else{
3420       rc = SQLITE_NOTFOUND;
3421     }
3422     sqlite3BtreeLeave(pBtree);
3423   }
3424   sqlite3_mutex_leave(db->mutex);
3425   return rc;
3426 }
3427 
3428 /*
3429 ** Interface to the testing logic.
3430 */
3431 int sqlite3_test_control(int op, ...){
3432   int rc = 0;
3433 #ifdef SQLITE_OMIT_BUILTIN_TEST
3434   UNUSED_PARAMETER(op);
3435 #else
3436   va_list ap;
3437   va_start(ap, op);
3438   switch( op ){
3439 
3440     /*
3441     ** Save the current state of the PRNG.
3442     */
3443     case SQLITE_TESTCTRL_PRNG_SAVE: {
3444       sqlite3PrngSaveState();
3445       break;
3446     }
3447 
3448     /*
3449     ** Restore the state of the PRNG to the last state saved using
3450     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3451     ** this verb acts like PRNG_RESET.
3452     */
3453     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3454       sqlite3PrngRestoreState();
3455       break;
3456     }
3457 
3458     /*
3459     ** Reset the PRNG back to its uninitialized state.  The next call
3460     ** to sqlite3_randomness() will reseed the PRNG using a single call
3461     ** to the xRandomness method of the default VFS.
3462     */
3463     case SQLITE_TESTCTRL_PRNG_RESET: {
3464       sqlite3_randomness(0,0);
3465       break;
3466     }
3467 
3468     /*
3469     **  sqlite3_test_control(BITVEC_TEST, size, program)
3470     **
3471     ** Run a test against a Bitvec object of size.  The program argument
3472     ** is an array of integers that defines the test.  Return -1 on a
3473     ** memory allocation error, 0 on success, or non-zero for an error.
3474     ** See the sqlite3BitvecBuiltinTest() for additional information.
3475     */
3476     case SQLITE_TESTCTRL_BITVEC_TEST: {
3477       int sz = va_arg(ap, int);
3478       int *aProg = va_arg(ap, int*);
3479       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3480       break;
3481     }
3482 
3483     /*
3484     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3485     **
3486     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3487     ** if xCallback is not NULL.
3488     **
3489     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3490     ** is called immediately after installing the new callback and the return
3491     ** value from sqlite3FaultSim(0) becomes the return from
3492     ** sqlite3_test_control().
3493     */
3494     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3495       /* MSVC is picky about pulling func ptrs from va lists.
3496       ** http://support.microsoft.com/kb/47961
3497       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3498       */
3499       typedef int(*TESTCALLBACKFUNC_t)(int);
3500       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3501       rc = sqlite3FaultSim(0);
3502       break;
3503     }
3504 
3505     /*
3506     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3507     **
3508     ** Register hooks to call to indicate which malloc() failures
3509     ** are benign.
3510     */
3511     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3512       typedef void (*void_function)(void);
3513       void_function xBenignBegin;
3514       void_function xBenignEnd;
3515       xBenignBegin = va_arg(ap, void_function);
3516       xBenignEnd = va_arg(ap, void_function);
3517       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3518       break;
3519     }
3520 
3521     /*
3522     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3523     **
3524     ** Set the PENDING byte to the value in the argument, if X>0.
3525     ** Make no changes if X==0.  Return the value of the pending byte
3526     ** as it existing before this routine was called.
3527     **
3528     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3529     ** an incompatible database file format.  Changing the PENDING byte
3530     ** while any database connection is open results in undefined and
3531     ** deleterious behavior.
3532     */
3533     case SQLITE_TESTCTRL_PENDING_BYTE: {
3534       rc = PENDING_BYTE;
3535 #ifndef SQLITE_OMIT_WSD
3536       {
3537         unsigned int newVal = va_arg(ap, unsigned int);
3538         if( newVal ) sqlite3PendingByte = newVal;
3539       }
3540 #endif
3541       break;
3542     }
3543 
3544     /*
3545     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3546     **
3547     ** This action provides a run-time test to see whether or not
3548     ** assert() was enabled at compile-time.  If X is true and assert()
3549     ** is enabled, then the return value is true.  If X is true and
3550     ** assert() is disabled, then the return value is zero.  If X is
3551     ** false and assert() is enabled, then the assertion fires and the
3552     ** process aborts.  If X is false and assert() is disabled, then the
3553     ** return value is zero.
3554     */
3555     case SQLITE_TESTCTRL_ASSERT: {
3556       volatile int x = 0;
3557       assert( (x = va_arg(ap,int))!=0 );
3558       rc = x;
3559       break;
3560     }
3561 
3562 
3563     /*
3564     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3565     **
3566     ** This action provides a run-time test to see how the ALWAYS and
3567     ** NEVER macros were defined at compile-time.
3568     **
3569     ** The return value is ALWAYS(X).
3570     **
3571     ** The recommended test is X==2.  If the return value is 2, that means
3572     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3573     ** default setting.  If the return value is 1, then ALWAYS() is either
3574     ** hard-coded to true or else it asserts if its argument is false.
3575     ** The first behavior (hard-coded to true) is the case if
3576     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3577     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3578     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3579     **
3580     ** The run-time test procedure might look something like this:
3581     **
3582     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3583     **      // ALWAYS() and NEVER() are no-op pass-through macros
3584     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3585     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3586     **    }else{
3587     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3588     **    }
3589     */
3590     case SQLITE_TESTCTRL_ALWAYS: {
3591       int x = va_arg(ap,int);
3592       rc = ALWAYS(x);
3593       break;
3594     }
3595 
3596     /*
3597     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3598     **
3599     ** The integer returned reveals the byte-order of the computer on which
3600     ** SQLite is running:
3601     **
3602     **       1     big-endian,    determined at run-time
3603     **      10     little-endian, determined at run-time
3604     **  432101     big-endian,    determined at compile-time
3605     **  123410     little-endian, determined at compile-time
3606     */
3607     case SQLITE_TESTCTRL_BYTEORDER: {
3608       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3609       break;
3610     }
3611 
3612     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3613     **
3614     ** Set the nReserve size to N for the main database on the database
3615     ** connection db.
3616     */
3617     case SQLITE_TESTCTRL_RESERVE: {
3618       sqlite3 *db = va_arg(ap, sqlite3*);
3619       int x = va_arg(ap,int);
3620       sqlite3_mutex_enter(db->mutex);
3621       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3622       sqlite3_mutex_leave(db->mutex);
3623       break;
3624     }
3625 
3626     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3627     **
3628     ** Enable or disable various optimizations for testing purposes.  The
3629     ** argument N is a bitmask of optimizations to be disabled.  For normal
3630     ** operation N should be 0.  The idea is that a test program (like the
3631     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3632     ** with various optimizations disabled to verify that the same answer
3633     ** is obtained in every case.
3634     */
3635     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3636       sqlite3 *db = va_arg(ap, sqlite3*);
3637       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3638       break;
3639     }
3640 
3641 #ifdef SQLITE_N_KEYWORD
3642     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3643     **
3644     ** If zWord is a keyword recognized by the parser, then return the
3645     ** number of keywords.  Or if zWord is not a keyword, return 0.
3646     **
3647     ** This test feature is only available in the amalgamation since
3648     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3649     ** is built using separate source files.
3650     */
3651     case SQLITE_TESTCTRL_ISKEYWORD: {
3652       const char *zWord = va_arg(ap, const char*);
3653       int n = sqlite3Strlen30(zWord);
3654       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3655       break;
3656     }
3657 #endif
3658 
3659     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3660     **
3661     ** Pass pFree into sqlite3ScratchFree().
3662     ** If sz>0 then allocate a scratch buffer into pNew.
3663     */
3664     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3665       void *pFree, **ppNew;
3666       int sz;
3667       sz = va_arg(ap, int);
3668       ppNew = va_arg(ap, void**);
3669       pFree = va_arg(ap, void*);
3670       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3671       sqlite3ScratchFree(pFree);
3672       break;
3673     }
3674 
3675     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3676     **
3677     ** If parameter onoff is non-zero, configure the wrappers so that all
3678     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3679     ** undo this setting.
3680     */
3681     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3682       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3683       break;
3684     }
3685 
3686     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3687     **
3688     ** Set or clear a flag that indicates that the database file is always well-
3689     ** formed and never corrupt.  This flag is clear by default, indicating that
3690     ** database files might have arbitrary corruption.  Setting the flag during
3691     ** testing causes certain assert() statements in the code to be activated
3692     ** that demonstrat invariants on well-formed database files.
3693     */
3694     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3695       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3696       break;
3697     }
3698 
3699 
3700     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3701     **
3702     ** Set the VDBE coverage callback function to xCallback with context
3703     ** pointer ptr.
3704     */
3705     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3706 #ifdef SQLITE_VDBE_COVERAGE
3707       typedef void (*branch_callback)(void*,int,u8,u8);
3708       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3709       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3710 #endif
3711       break;
3712     }
3713 
3714     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3715     case SQLITE_TESTCTRL_SORTER_MMAP: {
3716       sqlite3 *db = va_arg(ap, sqlite3*);
3717       db->nMaxSorterMmap = va_arg(ap, int);
3718       break;
3719     }
3720 
3721     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3722     **
3723     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3724     ** not.
3725     */
3726     case SQLITE_TESTCTRL_ISINIT: {
3727       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3728       break;
3729     }
3730 
3731     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3732     **
3733     ** This test control is used to create imposter tables.  "db" is a pointer
3734     ** to the database connection.  dbName is the database name (ex: "main" or
3735     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3736     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3737     ** table should connect.
3738     **
3739     ** Enable imposter mode only when the schema has already been parsed.  Then
3740     ** run a single CREATE TABLE statement to construct the imposter table in
3741     ** the parsed schema.  Then turn imposter mode back off again.
3742     **
3743     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3744     ** the schema to be reparsed the next time it is needed.  This has the
3745     ** effect of erasing all imposter tables.
3746     */
3747     case SQLITE_TESTCTRL_IMPOSTER: {
3748       sqlite3 *db = va_arg(ap, sqlite3*);
3749       sqlite3_mutex_enter(db->mutex);
3750       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3751       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3752       db->init.newTnum = va_arg(ap,int);
3753       if( db->init.busy==0 && db->init.newTnum>0 ){
3754         sqlite3ResetAllSchemasOfConnection(db);
3755       }
3756       sqlite3_mutex_leave(db->mutex);
3757       break;
3758     }
3759   }
3760   va_end(ap);
3761 #endif /* SQLITE_OMIT_BUILTIN_TEST */
3762   return rc;
3763 }
3764 
3765 /*
3766 ** This is a utility routine, useful to VFS implementations, that checks
3767 ** to see if a database file was a URI that contained a specific query
3768 ** parameter, and if so obtains the value of the query parameter.
3769 **
3770 ** The zFilename argument is the filename pointer passed into the xOpen()
3771 ** method of a VFS implementation.  The zParam argument is the name of the
3772 ** query parameter we seek.  This routine returns the value of the zParam
3773 ** parameter if it exists.  If the parameter does not exist, this routine
3774 ** returns a NULL pointer.
3775 */
3776 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3777   if( zFilename==0 || zParam==0 ) return 0;
3778   zFilename += sqlite3Strlen30(zFilename) + 1;
3779   while( zFilename[0] ){
3780     int x = strcmp(zFilename, zParam);
3781     zFilename += sqlite3Strlen30(zFilename) + 1;
3782     if( x==0 ) return zFilename;
3783     zFilename += sqlite3Strlen30(zFilename) + 1;
3784   }
3785   return 0;
3786 }
3787 
3788 /*
3789 ** Return a boolean value for a query parameter.
3790 */
3791 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3792   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3793   bDflt = bDflt!=0;
3794   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3795 }
3796 
3797 /*
3798 ** Return a 64-bit integer value for a query parameter.
3799 */
3800 sqlite3_int64 sqlite3_uri_int64(
3801   const char *zFilename,    /* Filename as passed to xOpen */
3802   const char *zParam,       /* URI parameter sought */
3803   sqlite3_int64 bDflt       /* return if parameter is missing */
3804 ){
3805   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3806   sqlite3_int64 v;
3807   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3808     bDflt = v;
3809   }
3810   return bDflt;
3811 }
3812 
3813 /*
3814 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3815 */
3816 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3817   int i;
3818   for(i=0; i<db->nDb; i++){
3819     if( db->aDb[i].pBt
3820      && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
3821     ){
3822       return db->aDb[i].pBt;
3823     }
3824   }
3825   return 0;
3826 }
3827 
3828 /*
3829 ** Return the filename of the database associated with a database
3830 ** connection.
3831 */
3832 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3833   Btree *pBt;
3834 #ifdef SQLITE_ENABLE_API_ARMOR
3835   if( !sqlite3SafetyCheckOk(db) ){
3836     (void)SQLITE_MISUSE_BKPT;
3837     return 0;
3838   }
3839 #endif
3840   pBt = sqlite3DbNameToBtree(db, zDbName);
3841   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3842 }
3843 
3844 /*
3845 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3846 ** no such database exists.
3847 */
3848 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3849   Btree *pBt;
3850 #ifdef SQLITE_ENABLE_API_ARMOR
3851   if( !sqlite3SafetyCheckOk(db) ){
3852     (void)SQLITE_MISUSE_BKPT;
3853     return -1;
3854   }
3855 #endif
3856   pBt = sqlite3DbNameToBtree(db, zDbName);
3857   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
3858 }
3859