xref: /sqlite-3.40.0/src/main.c (revision 4b8035e6)
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_STMTVTAB
32 int sqlite3StmtVtabInit(sqlite3*);
33 #endif
34 #ifdef SQLITE_ENABLE_FTS5
35 int sqlite3Fts5Init(sqlite3*);
36 #endif
37 
38 #ifndef SQLITE_AMALGAMATION
39 /* IMPLEMENTATION-OF: R-46656-45156 The sqlite3_version[] string constant
40 ** contains the text of SQLITE_VERSION macro.
41 */
42 const char sqlite3_version[] = SQLITE_VERSION;
43 #endif
44 
45 /* IMPLEMENTATION-OF: R-53536-42575 The sqlite3_libversion() function returns
46 ** a pointer to the to the sqlite3_version[] string constant.
47 */
48 const char *sqlite3_libversion(void){ return sqlite3_version; }
49 
50 /* IMPLEMENTATION-OF: R-63124-39300 The sqlite3_sourceid() function returns a
51 ** pointer to a string constant whose value is the same as the
52 ** SQLITE_SOURCE_ID C preprocessor macro.
53 */
54 const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
55 
56 /* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
57 ** returns an integer equal to SQLITE_VERSION_NUMBER.
58 */
59 int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }
60 
61 /* IMPLEMENTATION-OF: R-20790-14025 The sqlite3_threadsafe() function returns
62 ** zero if and only if SQLite was compiled with mutexing code omitted due to
63 ** the SQLITE_THREADSAFE compile-time option being set to 0.
64 */
65 int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }
66 
67 /*
68 ** When compiling the test fixture or with debugging enabled (on Win32),
69 ** this variable being set to non-zero will cause OSTRACE macros to emit
70 ** extra diagnostic information.
71 */
72 #ifdef SQLITE_HAVE_OS_TRACE
73 # ifndef SQLITE_DEBUG_OS_TRACE
74 #   define SQLITE_DEBUG_OS_TRACE 0
75 # endif
76   int sqlite3OSTrace = SQLITE_DEBUG_OS_TRACE;
77 #endif
78 
79 #if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
80 /*
81 ** If the following function pointer is not NULL and if
82 ** SQLITE_ENABLE_IOTRACE is enabled, then messages describing
83 ** I/O active are written using this function.  These messages
84 ** are intended for debugging activity only.
85 */
86 SQLITE_API void (SQLITE_CDECL *sqlite3IoTrace)(const char*, ...) = 0;
87 #endif
88 
89 /*
90 ** If the following global variable points to a string which is the
91 ** name of a directory, then that directory will be used to store
92 ** temporary files.
93 **
94 ** See also the "PRAGMA temp_store_directory" SQL command.
95 */
96 char *sqlite3_temp_directory = 0;
97 
98 /*
99 ** If the following global variable points to a string which is the
100 ** name of a directory, then that directory will be used to store
101 ** all database files specified with a relative pathname.
102 **
103 ** See also the "PRAGMA data_store_directory" SQL command.
104 */
105 char *sqlite3_data_directory = 0;
106 
107 /*
108 ** Initialize SQLite.
109 **
110 ** This routine must be called to initialize the memory allocation,
111 ** VFS, and mutex subsystems prior to doing any serious work with
112 ** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
113 ** this routine will be called automatically by key routines such as
114 ** sqlite3_open().
115 **
116 ** This routine is a no-op except on its very first call for the process,
117 ** or for the first call after a call to sqlite3_shutdown.
118 **
119 ** The first thread to call this routine runs the initialization to
120 ** completion.  If subsequent threads call this routine before the first
121 ** thread has finished the initialization process, then the subsequent
122 ** threads must block until the first thread finishes with the initialization.
123 **
124 ** The first thread might call this routine recursively.  Recursive
125 ** calls to this routine should not block, of course.  Otherwise the
126 ** initialization process would never complete.
127 **
128 ** Let X be the first thread to enter this routine.  Let Y be some other
129 ** thread.  Then while the initial invocation of this routine by X is
130 ** incomplete, it is required that:
131 **
132 **    *  Calls to this routine from Y must block until the outer-most
133 **       call by X completes.
134 **
135 **    *  Recursive calls to this routine from thread X return immediately
136 **       without blocking.
137 */
138 int sqlite3_initialize(void){
139   MUTEX_LOGIC( sqlite3_mutex *pMaster; )       /* The main static mutex */
140   int rc;                                      /* Result code */
141 #ifdef SQLITE_EXTRA_INIT
142   int bRunExtraInit = 0;                       /* Extra initialization needed */
143 #endif
144 
145 #ifdef SQLITE_OMIT_WSD
146   rc = sqlite3_wsd_init(4096, 24);
147   if( rc!=SQLITE_OK ){
148     return rc;
149   }
150 #endif
151 
152   /* If the following assert() fails on some obscure processor/compiler
153   ** combination, the work-around is to set the correct pointer
154   ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
155   assert( SQLITE_PTRSIZE==sizeof(char*) );
156 
157   /* If SQLite is already completely initialized, then this call
158   ** to sqlite3_initialize() should be a no-op.  But the initialization
159   ** must be complete.  So isInit must not be set until the very end
160   ** of this routine.
161   */
162   if( sqlite3GlobalConfig.isInit ) return SQLITE_OK;
163 
164   /* Make sure the mutex subsystem is initialized.  If unable to
165   ** initialize the mutex subsystem, return early with the error.
166   ** If the system is so sick that we are unable to allocate a mutex,
167   ** there is not much SQLite is going to be able to do.
168   **
169   ** The mutex subsystem must take care of serializing its own
170   ** initialization.
171   */
172   rc = sqlite3MutexInit();
173   if( rc ) return rc;
174 
175   /* Initialize the malloc() system and the recursive pInitMutex mutex.
176   ** This operation is protected by the STATIC_MASTER mutex.  Note that
177   ** MutexAlloc() is called for a static mutex prior to initializing the
178   ** malloc subsystem - this implies that the allocation of a static
179   ** mutex must not require support from the malloc subsystem.
180   */
181   MUTEX_LOGIC( pMaster = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
182   sqlite3_mutex_enter(pMaster);
183   sqlite3GlobalConfig.isMutexInit = 1;
184   if( !sqlite3GlobalConfig.isMallocInit ){
185     rc = sqlite3MallocInit();
186   }
187   if( rc==SQLITE_OK ){
188     sqlite3GlobalConfig.isMallocInit = 1;
189     if( !sqlite3GlobalConfig.pInitMutex ){
190       sqlite3GlobalConfig.pInitMutex =
191            sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
192       if( sqlite3GlobalConfig.bCoreMutex && !sqlite3GlobalConfig.pInitMutex ){
193         rc = SQLITE_NOMEM_BKPT;
194       }
195     }
196   }
197   if( rc==SQLITE_OK ){
198     sqlite3GlobalConfig.nRefInitMutex++;
199   }
200   sqlite3_mutex_leave(pMaster);
201 
202   /* If rc is not SQLITE_OK at this point, then either the malloc
203   ** subsystem could not be initialized or the system failed to allocate
204   ** the pInitMutex mutex. Return an error in either case.  */
205   if( rc!=SQLITE_OK ){
206     return rc;
207   }
208 
209   /* Do the rest of the initialization under the recursive mutex so
210   ** that we will be able to handle recursive calls into
211   ** sqlite3_initialize().  The recursive calls normally come through
212   ** sqlite3_os_init() when it invokes sqlite3_vfs_register(), but other
213   ** recursive calls might also be possible.
214   **
215   ** IMPLEMENTATION-OF: R-00140-37445 SQLite automatically serializes calls
216   ** to the xInit method, so the xInit method need not be threadsafe.
217   **
218   ** The following mutex is what serializes access to the appdef pcache xInit
219   ** methods.  The sqlite3_pcache_methods.xInit() all is embedded in the
220   ** call to sqlite3PcacheInitialize().
221   */
222   sqlite3_mutex_enter(sqlite3GlobalConfig.pInitMutex);
223   if( sqlite3GlobalConfig.isInit==0 && sqlite3GlobalConfig.inProgress==0 ){
224     sqlite3GlobalConfig.inProgress = 1;
225 #ifdef SQLITE_ENABLE_SQLLOG
226     {
227       extern void sqlite3_init_sqllog(void);
228       sqlite3_init_sqllog();
229     }
230 #endif
231     memset(&sqlite3BuiltinFunctions, 0, sizeof(sqlite3BuiltinFunctions));
232     sqlite3RegisterBuiltinFunctions();
233     if( sqlite3GlobalConfig.isPCacheInit==0 ){
234       rc = sqlite3PcacheInitialize();
235     }
236     if( rc==SQLITE_OK ){
237       sqlite3GlobalConfig.isPCacheInit = 1;
238       rc = sqlite3OsInit();
239     }
240     if( rc==SQLITE_OK ){
241       sqlite3PCacheBufferSetup( sqlite3GlobalConfig.pPage,
242           sqlite3GlobalConfig.szPage, sqlite3GlobalConfig.nPage);
243       sqlite3GlobalConfig.isInit = 1;
244 #ifdef SQLITE_EXTRA_INIT
245       bRunExtraInit = 1;
246 #endif
247     }
248     sqlite3GlobalConfig.inProgress = 0;
249   }
250   sqlite3_mutex_leave(sqlite3GlobalConfig.pInitMutex);
251 
252   /* Go back under the static mutex and clean up the recursive
253   ** mutex to prevent a resource leak.
254   */
255   sqlite3_mutex_enter(pMaster);
256   sqlite3GlobalConfig.nRefInitMutex--;
257   if( sqlite3GlobalConfig.nRefInitMutex<=0 ){
258     assert( sqlite3GlobalConfig.nRefInitMutex==0 );
259     sqlite3_mutex_free(sqlite3GlobalConfig.pInitMutex);
260     sqlite3GlobalConfig.pInitMutex = 0;
261   }
262   sqlite3_mutex_leave(pMaster);
263 
264   /* The following is just a sanity check to make sure SQLite has
265   ** been compiled correctly.  It is important to run this code, but
266   ** we don't want to run it too often and soak up CPU cycles for no
267   ** reason.  So we run it once during initialization.
268   */
269 #ifndef NDEBUG
270 #ifndef SQLITE_OMIT_FLOATING_POINT
271   /* This section of code's only "output" is via assert() statements. */
272   if ( rc==SQLITE_OK ){
273     u64 x = (((u64)1)<<63)-1;
274     double y;
275     assert(sizeof(x)==8);
276     assert(sizeof(x)==sizeof(y));
277     memcpy(&y, &x, 8);
278     assert( sqlite3IsNaN(y) );
279   }
280 #endif
281 #endif
282 
283   /* Do extra initialization steps requested by the SQLITE_EXTRA_INIT
284   ** compile-time option.
285   */
286 #ifdef SQLITE_EXTRA_INIT
287   if( bRunExtraInit ){
288     int SQLITE_EXTRA_INIT(const char*);
289     rc = SQLITE_EXTRA_INIT(0);
290   }
291 #endif
292 
293   return rc;
294 }
295 
296 /*
297 ** Undo the effects of sqlite3_initialize().  Must not be called while
298 ** there are outstanding database connections or memory allocations or
299 ** while any part of SQLite is otherwise in use in any thread.  This
300 ** routine is not threadsafe.  But it is safe to invoke this routine
301 ** on when SQLite is already shut down.  If SQLite is already shut down
302 ** when this routine is invoked, then this routine is a harmless no-op.
303 */
304 int sqlite3_shutdown(void){
305 #ifdef SQLITE_OMIT_WSD
306   int rc = sqlite3_wsd_init(4096, 24);
307   if( rc!=SQLITE_OK ){
308     return rc;
309   }
310 #endif
311 
312   if( sqlite3GlobalConfig.isInit ){
313 #ifdef SQLITE_EXTRA_SHUTDOWN
314     void SQLITE_EXTRA_SHUTDOWN(void);
315     SQLITE_EXTRA_SHUTDOWN();
316 #endif
317     sqlite3_os_end();
318     sqlite3_reset_auto_extension();
319     sqlite3GlobalConfig.isInit = 0;
320   }
321   if( sqlite3GlobalConfig.isPCacheInit ){
322     sqlite3PcacheShutdown();
323     sqlite3GlobalConfig.isPCacheInit = 0;
324   }
325   if( sqlite3GlobalConfig.isMallocInit ){
326     sqlite3MallocEnd();
327     sqlite3GlobalConfig.isMallocInit = 0;
328 
329 #ifndef SQLITE_OMIT_SHUTDOWN_DIRECTORIES
330     /* The heap subsystem has now been shutdown and these values are supposed
331     ** to be NULL or point to memory that was obtained from sqlite3_malloc(),
332     ** which would rely on that heap subsystem; therefore, make sure these
333     ** values cannot refer to heap memory that was just invalidated when the
334     ** heap subsystem was shutdown.  This is only done if the current call to
335     ** this function resulted in the heap subsystem actually being shutdown.
336     */
337     sqlite3_data_directory = 0;
338     sqlite3_temp_directory = 0;
339 #endif
340   }
341   if( sqlite3GlobalConfig.isMutexInit ){
342     sqlite3MutexEnd();
343     sqlite3GlobalConfig.isMutexInit = 0;
344   }
345 
346   return SQLITE_OK;
347 }
348 
349 /*
350 ** This API allows applications to modify the global configuration of
351 ** the SQLite library at run-time.
352 **
353 ** This routine should only be called when there are no outstanding
354 ** database connections or memory allocations.  This routine is not
355 ** threadsafe.  Failure to heed these warnings can lead to unpredictable
356 ** behavior.
357 */
358 int sqlite3_config(int op, ...){
359   va_list ap;
360   int rc = SQLITE_OK;
361 
362   /* sqlite3_config() shall return SQLITE_MISUSE if it is invoked while
363   ** the SQLite library is in use. */
364   if( sqlite3GlobalConfig.isInit ) return SQLITE_MISUSE_BKPT;
365 
366   va_start(ap, op);
367   switch( op ){
368 
369     /* Mutex configuration options are only available in a threadsafe
370     ** compile.
371     */
372 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0  /* IMP: R-54466-46756 */
373     case SQLITE_CONFIG_SINGLETHREAD: {
374       /* EVIDENCE-OF: R-02748-19096 This option sets the threading mode to
375       ** Single-thread. */
376       sqlite3GlobalConfig.bCoreMutex = 0;  /* Disable mutex on core */
377       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
378       break;
379     }
380 #endif
381 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-20520-54086 */
382     case SQLITE_CONFIG_MULTITHREAD: {
383       /* EVIDENCE-OF: R-14374-42468 This option sets the threading mode to
384       ** Multi-thread. */
385       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
386       sqlite3GlobalConfig.bFullMutex = 0;  /* Disable mutex on connections */
387       break;
388     }
389 #endif
390 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-59593-21810 */
391     case SQLITE_CONFIG_SERIALIZED: {
392       /* EVIDENCE-OF: R-41220-51800 This option sets the threading mode to
393       ** Serialized. */
394       sqlite3GlobalConfig.bCoreMutex = 1;  /* Enable mutex on core */
395       sqlite3GlobalConfig.bFullMutex = 1;  /* Enable mutex on connections */
396       break;
397     }
398 #endif
399 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-63666-48755 */
400     case SQLITE_CONFIG_MUTEX: {
401       /* Specify an alternative mutex implementation */
402       sqlite3GlobalConfig.mutex = *va_arg(ap, sqlite3_mutex_methods*);
403       break;
404     }
405 #endif
406 #if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE>0 /* IMP: R-14450-37597 */
407     case SQLITE_CONFIG_GETMUTEX: {
408       /* Retrieve the current mutex implementation */
409       *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex;
410       break;
411     }
412 #endif
413 
414     case SQLITE_CONFIG_MALLOC: {
415       /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a
416       ** single argument which is a pointer to an instance of the
417       ** sqlite3_mem_methods structure. The argument specifies alternative
418       ** low-level memory allocation routines to be used in place of the memory
419       ** allocation routines built into SQLite. */
420       sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*);
421       break;
422     }
423     case SQLITE_CONFIG_GETMALLOC: {
424       /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a
425       ** single argument which is a pointer to an instance of the
426       ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is
427       ** filled with the currently defined memory allocation routines. */
428       if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault();
429       *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m;
430       break;
431     }
432     case SQLITE_CONFIG_MEMSTATUS: {
433       /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes
434       ** single argument of type int, interpreted as a boolean, which enables
435       ** or disables the collection of memory allocation statistics. */
436       sqlite3GlobalConfig.bMemstat = va_arg(ap, int);
437       break;
438     }
439     case SQLITE_CONFIG_SCRATCH: {
440       /* EVIDENCE-OF: R-08404-60887 There are three arguments to
441       ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from
442       ** which the scratch allocations will be drawn, the size of each scratch
443       ** allocation (sz), and the maximum number of scratch allocations (N). */
444       sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
445       sqlite3GlobalConfig.szScratch = va_arg(ap, int);
446       sqlite3GlobalConfig.nScratch = va_arg(ap, int);
447       break;
448     }
449     case SQLITE_CONFIG_PAGECACHE: {
450       /* EVIDENCE-OF: R-18761-36601 There are three arguments to
451       ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
452       ** the size of each page cache line (sz), and the number of cache lines
453       ** (N). */
454       sqlite3GlobalConfig.pPage = va_arg(ap, void*);
455       sqlite3GlobalConfig.szPage = va_arg(ap, int);
456       sqlite3GlobalConfig.nPage = va_arg(ap, int);
457       break;
458     }
459     case SQLITE_CONFIG_PCACHE_HDRSZ: {
460       /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes
461       ** a single parameter which is a pointer to an integer and writes into
462       ** that integer the number of extra bytes per page required for each page
463       ** in SQLITE_CONFIG_PAGECACHE. */
464       *va_arg(ap, int*) =
465           sqlite3HeaderSizeBtree() +
466           sqlite3HeaderSizePcache() +
467           sqlite3HeaderSizePcache1();
468       break;
469     }
470 
471     case SQLITE_CONFIG_PCACHE: {
472       /* no-op */
473       break;
474     }
475     case SQLITE_CONFIG_GETPCACHE: {
476       /* now an error */
477       rc = SQLITE_ERROR;
478       break;
479     }
480 
481     case SQLITE_CONFIG_PCACHE2: {
482       /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a
483       ** single argument which is a pointer to an sqlite3_pcache_methods2
484       ** object. This object specifies the interface to a custom page cache
485       ** implementation. */
486       sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*);
487       break;
488     }
489     case SQLITE_CONFIG_GETPCACHE2: {
490       /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a
491       ** single argument which is a pointer to an sqlite3_pcache_methods2
492       ** object. SQLite copies of the current page cache implementation into
493       ** that object. */
494       if( sqlite3GlobalConfig.pcache2.xInit==0 ){
495         sqlite3PCacheSetDefault();
496       }
497       *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2;
498       break;
499     }
500 
501 /* EVIDENCE-OF: R-06626-12911 The SQLITE_CONFIG_HEAP option is only
502 ** available if SQLite is compiled with either SQLITE_ENABLE_MEMSYS3 or
503 ** SQLITE_ENABLE_MEMSYS5 and returns SQLITE_ERROR if invoked otherwise. */
504 #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5)
505     case SQLITE_CONFIG_HEAP: {
506       /* EVIDENCE-OF: R-19854-42126 There are three arguments to
507       ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the
508       ** number of bytes in the memory buffer, and the minimum allocation size.
509       */
510       sqlite3GlobalConfig.pHeap = va_arg(ap, void*);
511       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
512       sqlite3GlobalConfig.mnReq = va_arg(ap, int);
513 
514       if( sqlite3GlobalConfig.mnReq<1 ){
515         sqlite3GlobalConfig.mnReq = 1;
516       }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){
517         /* cap min request size at 2^12 */
518         sqlite3GlobalConfig.mnReq = (1<<12);
519       }
520 
521       if( sqlite3GlobalConfig.pHeap==0 ){
522         /* EVIDENCE-OF: R-49920-60189 If the first pointer (the memory pointer)
523         ** is NULL, then SQLite reverts to using its default memory allocator
524         ** (the system malloc() implementation), undoing any prior invocation of
525         ** SQLITE_CONFIG_MALLOC.
526         **
527         ** Setting sqlite3GlobalConfig.m to all zeros will cause malloc to
528         ** revert to its default implementation when sqlite3_initialize() is run
529         */
530         memset(&sqlite3GlobalConfig.m, 0, sizeof(sqlite3GlobalConfig.m));
531       }else{
532         /* EVIDENCE-OF: R-61006-08918 If the memory pointer is not NULL then the
533         ** alternative memory allocator is engaged to handle all of SQLites
534         ** memory allocation needs. */
535 #ifdef SQLITE_ENABLE_MEMSYS3
536         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys3();
537 #endif
538 #ifdef SQLITE_ENABLE_MEMSYS5
539         sqlite3GlobalConfig.m = *sqlite3MemGetMemsys5();
540 #endif
541       }
542       break;
543     }
544 #endif
545 
546     case SQLITE_CONFIG_LOOKASIDE: {
547       sqlite3GlobalConfig.szLookaside = va_arg(ap, int);
548       sqlite3GlobalConfig.nLookaside = va_arg(ap, int);
549       break;
550     }
551 
552     /* Record a pointer to the logger function and its first argument.
553     ** The default is NULL.  Logging is disabled if the function pointer is
554     ** NULL.
555     */
556     case SQLITE_CONFIG_LOG: {
557       /* MSVC is picky about pulling func ptrs from va lists.
558       ** http://support.microsoft.com/kb/47961
559       ** sqlite3GlobalConfig.xLog = va_arg(ap, void(*)(void*,int,const char*));
560       */
561       typedef void(*LOGFUNC_t)(void*,int,const char*);
562       sqlite3GlobalConfig.xLog = va_arg(ap, LOGFUNC_t);
563       sqlite3GlobalConfig.pLogArg = va_arg(ap, void*);
564       break;
565     }
566 
567     /* EVIDENCE-OF: R-55548-33817 The compile-time setting for URI filenames
568     ** can be changed at start-time using the
569     ** sqlite3_config(SQLITE_CONFIG_URI,1) or
570     ** sqlite3_config(SQLITE_CONFIG_URI,0) configuration calls.
571     */
572     case SQLITE_CONFIG_URI: {
573       /* EVIDENCE-OF: R-25451-61125 The SQLITE_CONFIG_URI option takes a single
574       ** argument of type int. If non-zero, then URI handling is globally
575       ** enabled. If the parameter is zero, then URI handling is globally
576       ** disabled. */
577       sqlite3GlobalConfig.bOpenUri = va_arg(ap, int);
578       break;
579     }
580 
581     case SQLITE_CONFIG_COVERING_INDEX_SCAN: {
582       /* EVIDENCE-OF: R-36592-02772 The SQLITE_CONFIG_COVERING_INDEX_SCAN
583       ** option takes a single integer argument which is interpreted as a
584       ** boolean in order to enable or disable the use of covering indices for
585       ** full table scans in the query optimizer. */
586       sqlite3GlobalConfig.bUseCis = va_arg(ap, int);
587       break;
588     }
589 
590 #ifdef SQLITE_ENABLE_SQLLOG
591     case SQLITE_CONFIG_SQLLOG: {
592       typedef void(*SQLLOGFUNC_t)(void*, sqlite3*, const char*, int);
593       sqlite3GlobalConfig.xSqllog = va_arg(ap, SQLLOGFUNC_t);
594       sqlite3GlobalConfig.pSqllogArg = va_arg(ap, void *);
595       break;
596     }
597 #endif
598 
599     case SQLITE_CONFIG_MMAP_SIZE: {
600       /* EVIDENCE-OF: R-58063-38258 SQLITE_CONFIG_MMAP_SIZE takes two 64-bit
601       ** integer (sqlite3_int64) values that are the default mmap size limit
602       ** (the default setting for PRAGMA mmap_size) and the maximum allowed
603       ** mmap size limit. */
604       sqlite3_int64 szMmap = va_arg(ap, sqlite3_int64);
605       sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
606       /* EVIDENCE-OF: R-53367-43190 If either argument to this option is
607       ** negative, then that argument is changed to its compile-time default.
608       **
609       ** EVIDENCE-OF: R-34993-45031 The maximum allowed mmap size will be
610       ** silently truncated if necessary so that it does not exceed the
611       ** compile-time maximum mmap size set by the SQLITE_MAX_MMAP_SIZE
612       ** compile-time option.
613       */
614       if( mxMmap<0 || mxMmap>SQLITE_MAX_MMAP_SIZE ){
615         mxMmap = SQLITE_MAX_MMAP_SIZE;
616       }
617       if( szMmap<0 ) szMmap = SQLITE_DEFAULT_MMAP_SIZE;
618       if( szMmap>mxMmap) szMmap = mxMmap;
619       sqlite3GlobalConfig.mxMmap = mxMmap;
620       sqlite3GlobalConfig.szMmap = szMmap;
621       break;
622     }
623 
624 #if SQLITE_OS_WIN && defined(SQLITE_WIN32_MALLOC) /* IMP: R-04780-55815 */
625     case SQLITE_CONFIG_WIN32_HEAPSIZE: {
626       /* EVIDENCE-OF: R-34926-03360 SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit
627       ** unsigned integer value that specifies the maximum size of the created
628       ** heap. */
629       sqlite3GlobalConfig.nHeap = va_arg(ap, int);
630       break;
631     }
632 #endif
633 
634     case SQLITE_CONFIG_PMASZ: {
635       sqlite3GlobalConfig.szPma = va_arg(ap, unsigned int);
636       break;
637     }
638 
639     case SQLITE_CONFIG_STMTJRNL_SPILL: {
640       sqlite3GlobalConfig.nStmtSpill = va_arg(ap, int);
641       break;
642     }
643 
644     default: {
645       rc = SQLITE_ERROR;
646       break;
647     }
648   }
649   va_end(ap);
650   return rc;
651 }
652 
653 /*
654 ** Set up the lookaside buffers for a database connection.
655 ** Return SQLITE_OK on success.
656 ** If lookaside is already active, return SQLITE_BUSY.
657 **
658 ** The sz parameter is the number of bytes in each lookaside slot.
659 ** The cnt parameter is the number of slots.  If pStart is NULL the
660 ** space for the lookaside memory is obtained from sqlite3_malloc().
661 ** If pStart is not NULL then it is sz*cnt bytes of memory to use for
662 ** the lookaside memory.
663 */
664 static int setupLookaside(sqlite3 *db, void *pBuf, int sz, int cnt){
665 #ifndef SQLITE_OMIT_LOOKASIDE
666   void *pStart;
667   if( db->lookaside.nOut ){
668     return SQLITE_BUSY;
669   }
670   /* Free any existing lookaside buffer for this handle before
671   ** allocating a new one so we don't have to have space for
672   ** both at the same time.
673   */
674   if( db->lookaside.bMalloced ){
675     sqlite3_free(db->lookaside.pStart);
676   }
677   /* The size of a lookaside slot after ROUNDDOWN8 needs to be larger
678   ** than a pointer to be useful.
679   */
680   sz = ROUNDDOWN8(sz);  /* IMP: R-33038-09382 */
681   if( sz<=(int)sizeof(LookasideSlot*) ) sz = 0;
682   if( cnt<0 ) cnt = 0;
683   if( sz==0 || cnt==0 ){
684     sz = 0;
685     pStart = 0;
686   }else if( pBuf==0 ){
687     sqlite3BeginBenignMalloc();
688     pStart = sqlite3Malloc( sz*cnt );  /* IMP: R-61949-35727 */
689     sqlite3EndBenignMalloc();
690     if( pStart ) cnt = sqlite3MallocSize(pStart)/sz;
691   }else{
692     pStart = pBuf;
693   }
694   db->lookaside.pStart = pStart;
695   db->lookaside.pFree = 0;
696   db->lookaside.sz = (u16)sz;
697   if( pStart ){
698     int i;
699     LookasideSlot *p;
700     assert( sz > (int)sizeof(LookasideSlot*) );
701     p = (LookasideSlot*)pStart;
702     for(i=cnt-1; i>=0; i--){
703       p->pNext = db->lookaside.pFree;
704       db->lookaside.pFree = p;
705       p = (LookasideSlot*)&((u8*)p)[sz];
706     }
707     db->lookaside.pEnd = p;
708     db->lookaside.bDisable = 0;
709     db->lookaside.bMalloced = pBuf==0 ?1:0;
710   }else{
711     db->lookaside.pStart = db;
712     db->lookaside.pEnd = db;
713     db->lookaside.bDisable = 1;
714     db->lookaside.bMalloced = 0;
715   }
716 #endif /* SQLITE_OMIT_LOOKASIDE */
717   return SQLITE_OK;
718 }
719 
720 /*
721 ** Return the mutex associated with a database connection.
722 */
723 sqlite3_mutex *sqlite3_db_mutex(sqlite3 *db){
724 #ifdef SQLITE_ENABLE_API_ARMOR
725   if( !sqlite3SafetyCheckOk(db) ){
726     (void)SQLITE_MISUSE_BKPT;
727     return 0;
728   }
729 #endif
730   return db->mutex;
731 }
732 
733 /*
734 ** Free up as much memory as we can from the given database
735 ** connection.
736 */
737 int sqlite3_db_release_memory(sqlite3 *db){
738   int i;
739 
740 #ifdef SQLITE_ENABLE_API_ARMOR
741   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
742 #endif
743   sqlite3_mutex_enter(db->mutex);
744   sqlite3BtreeEnterAll(db);
745   for(i=0; i<db->nDb; i++){
746     Btree *pBt = db->aDb[i].pBt;
747     if( pBt ){
748       Pager *pPager = sqlite3BtreePager(pBt);
749       sqlite3PagerShrink(pPager);
750     }
751   }
752   sqlite3BtreeLeaveAll(db);
753   sqlite3_mutex_leave(db->mutex);
754   return SQLITE_OK;
755 }
756 
757 /*
758 ** Flush any dirty pages in the pager-cache for any attached database
759 ** to disk.
760 */
761 int sqlite3_db_cacheflush(sqlite3 *db){
762   int i;
763   int rc = SQLITE_OK;
764   int bSeenBusy = 0;
765 
766 #ifdef SQLITE_ENABLE_API_ARMOR
767   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
768 #endif
769   sqlite3_mutex_enter(db->mutex);
770   sqlite3BtreeEnterAll(db);
771   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
772     Btree *pBt = db->aDb[i].pBt;
773     if( pBt && sqlite3BtreeIsInTrans(pBt) ){
774       Pager *pPager = sqlite3BtreePager(pBt);
775       rc = sqlite3PagerFlush(pPager);
776       if( rc==SQLITE_BUSY ){
777         bSeenBusy = 1;
778         rc = SQLITE_OK;
779       }
780     }
781   }
782   sqlite3BtreeLeaveAll(db);
783   sqlite3_mutex_leave(db->mutex);
784   return ((rc==SQLITE_OK && bSeenBusy) ? SQLITE_BUSY : rc);
785 }
786 
787 /*
788 ** Configuration settings for an individual database connection
789 */
790 int sqlite3_db_config(sqlite3 *db, int op, ...){
791   va_list ap;
792   int rc;
793   va_start(ap, op);
794   switch( op ){
795     case SQLITE_DBCONFIG_MAINDBNAME: {
796       db->aDb[0].zDbSName = va_arg(ap,char*);
797       rc = SQLITE_OK;
798       break;
799     }
800     case SQLITE_DBCONFIG_LOOKASIDE: {
801       void *pBuf = va_arg(ap, void*); /* IMP: R-26835-10964 */
802       int sz = va_arg(ap, int);       /* IMP: R-47871-25994 */
803       int cnt = va_arg(ap, int);      /* IMP: R-04460-53386 */
804       rc = setupLookaside(db, pBuf, sz, cnt);
805       break;
806     }
807     default: {
808       static const struct {
809         int op;      /* The opcode */
810         u32 mask;    /* Mask of the bit in sqlite3.flags to set/clear */
811       } aFlagOp[] = {
812         { SQLITE_DBCONFIG_ENABLE_FKEY,           SQLITE_ForeignKeys    },
813         { SQLITE_DBCONFIG_ENABLE_TRIGGER,        SQLITE_EnableTrigger  },
814         { SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, SQLITE_Fts3Tokenizer  },
815         { SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION, SQLITE_LoadExtension  },
816         { SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE,      SQLITE_NoCkptOnClose  },
817         { SQLITE_DBCONFIG_ENABLE_QPSG,           SQLITE_EnableQPSG     },
818       };
819       unsigned int i;
820       rc = SQLITE_ERROR; /* IMP: R-42790-23372 */
821       for(i=0; i<ArraySize(aFlagOp); i++){
822         if( aFlagOp[i].op==op ){
823           int onoff = va_arg(ap, int);
824           int *pRes = va_arg(ap, int*);
825           int oldFlags = db->flags;
826           if( onoff>0 ){
827             db->flags |= aFlagOp[i].mask;
828           }else if( onoff==0 ){
829             db->flags &= ~aFlagOp[i].mask;
830           }
831           if( oldFlags!=db->flags ){
832             sqlite3ExpirePreparedStatements(db);
833           }
834           if( pRes ){
835             *pRes = (db->flags & aFlagOp[i].mask)!=0;
836           }
837           rc = SQLITE_OK;
838           break;
839         }
840       }
841       break;
842     }
843   }
844   va_end(ap);
845   return rc;
846 }
847 
848 
849 /*
850 ** Return true if the buffer z[0..n-1] contains all spaces.
851 */
852 static int allSpaces(const char *z, int n){
853   while( n>0 && z[n-1]==' ' ){ n--; }
854   return n==0;
855 }
856 
857 /*
858 ** This is the default collating function named "BINARY" which is always
859 ** available.
860 **
861 ** If the padFlag argument is not NULL then space padding at the end
862 ** of strings is ignored.  This implements the RTRIM collation.
863 */
864 static int binCollFunc(
865   void *padFlag,
866   int nKey1, const void *pKey1,
867   int nKey2, const void *pKey2
868 ){
869   int rc, n;
870   n = nKey1<nKey2 ? nKey1 : nKey2;
871   /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
872   ** strings byte by byte using the memcmp() function from the standard C
873   ** library. */
874   assert( pKey1 && pKey2 );
875   rc = memcmp(pKey1, pKey2, n);
876   if( rc==0 ){
877     if( padFlag
878      && allSpaces(((char*)pKey1)+n, nKey1-n)
879      && allSpaces(((char*)pKey2)+n, nKey2-n)
880     ){
881       /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
882       ** spaces at the end of either string do not change the result. In other
883       ** words, strings will compare equal to one another as long as they
884       ** differ only in the number of spaces at the end.
885       */
886     }else{
887       rc = nKey1 - nKey2;
888     }
889   }
890   return rc;
891 }
892 
893 /*
894 ** Another built-in collating sequence: NOCASE.
895 **
896 ** This collating sequence is intended to be used for "case independent
897 ** comparison". SQLite's knowledge of upper and lower case equivalents
898 ** extends only to the 26 characters used in the English language.
899 **
900 ** At the moment there is only a UTF-8 implementation.
901 */
902 static int nocaseCollatingFunc(
903   void *NotUsed,
904   int nKey1, const void *pKey1,
905   int nKey2, const void *pKey2
906 ){
907   int r = sqlite3StrNICmp(
908       (const char *)pKey1, (const char *)pKey2, (nKey1<nKey2)?nKey1:nKey2);
909   UNUSED_PARAMETER(NotUsed);
910   if( 0==r ){
911     r = nKey1-nKey2;
912   }
913   return r;
914 }
915 
916 /*
917 ** Return the ROWID of the most recent insert
918 */
919 sqlite_int64 sqlite3_last_insert_rowid(sqlite3 *db){
920 #ifdef SQLITE_ENABLE_API_ARMOR
921   if( !sqlite3SafetyCheckOk(db) ){
922     (void)SQLITE_MISUSE_BKPT;
923     return 0;
924   }
925 #endif
926   return db->lastRowid;
927 }
928 
929 /*
930 ** Set the value returned by the sqlite3_last_insert_rowid() API function.
931 */
932 void sqlite3_set_last_insert_rowid(sqlite3 *db, sqlite3_int64 iRowid){
933 #ifdef SQLITE_ENABLE_API_ARMOR
934   if( !sqlite3SafetyCheckOk(db) ){
935     (void)SQLITE_MISUSE_BKPT;
936     return;
937   }
938 #endif
939   sqlite3_mutex_enter(db->mutex);
940   db->lastRowid = iRowid;
941   sqlite3_mutex_leave(db->mutex);
942 }
943 
944 /*
945 ** Return the number of changes in the most recent call to sqlite3_exec().
946 */
947 int sqlite3_changes(sqlite3 *db){
948 #ifdef SQLITE_ENABLE_API_ARMOR
949   if( !sqlite3SafetyCheckOk(db) ){
950     (void)SQLITE_MISUSE_BKPT;
951     return 0;
952   }
953 #endif
954   return db->nChange;
955 }
956 
957 /*
958 ** Return the number of changes since the database handle was opened.
959 */
960 int sqlite3_total_changes(sqlite3 *db){
961 #ifdef SQLITE_ENABLE_API_ARMOR
962   if( !sqlite3SafetyCheckOk(db) ){
963     (void)SQLITE_MISUSE_BKPT;
964     return 0;
965   }
966 #endif
967   return db->nTotalChange;
968 }
969 
970 /*
971 ** Close all open savepoints. This function only manipulates fields of the
972 ** database handle object, it does not close any savepoints that may be open
973 ** at the b-tree/pager level.
974 */
975 void sqlite3CloseSavepoints(sqlite3 *db){
976   while( db->pSavepoint ){
977     Savepoint *pTmp = db->pSavepoint;
978     db->pSavepoint = pTmp->pNext;
979     sqlite3DbFree(db, pTmp);
980   }
981   db->nSavepoint = 0;
982   db->nStatement = 0;
983   db->isTransactionSavepoint = 0;
984 }
985 
986 /*
987 ** Invoke the destructor function associated with FuncDef p, if any. Except,
988 ** if this is not the last copy of the function, do not invoke it. Multiple
989 ** copies of a single function are created when create_function() is called
990 ** with SQLITE_ANY as the encoding.
991 */
992 static void functionDestroy(sqlite3 *db, FuncDef *p){
993   FuncDestructor *pDestructor = p->u.pDestructor;
994   if( pDestructor ){
995     pDestructor->nRef--;
996     if( pDestructor->nRef==0 ){
997       pDestructor->xDestroy(pDestructor->pUserData);
998       sqlite3DbFree(db, pDestructor);
999     }
1000   }
1001 }
1002 
1003 /*
1004 ** Disconnect all sqlite3_vtab objects that belong to database connection
1005 ** db. This is called when db is being closed.
1006 */
1007 static void disconnectAllVtab(sqlite3 *db){
1008 #ifndef SQLITE_OMIT_VIRTUALTABLE
1009   int i;
1010   HashElem *p;
1011   sqlite3BtreeEnterAll(db);
1012   for(i=0; i<db->nDb; i++){
1013     Schema *pSchema = db->aDb[i].pSchema;
1014     if( db->aDb[i].pSchema ){
1015       for(p=sqliteHashFirst(&pSchema->tblHash); p; p=sqliteHashNext(p)){
1016         Table *pTab = (Table *)sqliteHashData(p);
1017         if( IsVirtual(pTab) ) sqlite3VtabDisconnect(db, pTab);
1018       }
1019     }
1020   }
1021   for(p=sqliteHashFirst(&db->aModule); p; p=sqliteHashNext(p)){
1022     Module *pMod = (Module *)sqliteHashData(p);
1023     if( pMod->pEpoTab ){
1024       sqlite3VtabDisconnect(db, pMod->pEpoTab);
1025     }
1026   }
1027   sqlite3VtabUnlockList(db);
1028   sqlite3BtreeLeaveAll(db);
1029 #else
1030   UNUSED_PARAMETER(db);
1031 #endif
1032 }
1033 
1034 /*
1035 ** Return TRUE if database connection db has unfinalized prepared
1036 ** statements or unfinished sqlite3_backup objects.
1037 */
1038 static int connectionIsBusy(sqlite3 *db){
1039   int j;
1040   assert( sqlite3_mutex_held(db->mutex) );
1041   if( db->pVdbe ) return 1;
1042   for(j=0; j<db->nDb; j++){
1043     Btree *pBt = db->aDb[j].pBt;
1044     if( pBt && sqlite3BtreeIsInBackup(pBt) ) return 1;
1045   }
1046   return 0;
1047 }
1048 
1049 /*
1050 ** Close an existing SQLite database
1051 */
1052 static int sqlite3Close(sqlite3 *db, int forceZombie){
1053   if( !db ){
1054     /* EVIDENCE-OF: R-63257-11740 Calling sqlite3_close() or
1055     ** sqlite3_close_v2() with a NULL pointer argument is a harmless no-op. */
1056     return SQLITE_OK;
1057   }
1058   if( !sqlite3SafetyCheckSickOrOk(db) ){
1059     return SQLITE_MISUSE_BKPT;
1060   }
1061   sqlite3_mutex_enter(db->mutex);
1062   if( db->mTrace & SQLITE_TRACE_CLOSE ){
1063     db->xTrace(SQLITE_TRACE_CLOSE, db->pTraceArg, db, 0);
1064   }
1065 
1066   /* Force xDisconnect calls on all virtual tables */
1067   disconnectAllVtab(db);
1068 
1069   /* If a transaction is open, the disconnectAllVtab() call above
1070   ** will not have called the xDisconnect() method on any virtual
1071   ** tables in the db->aVTrans[] array. The following sqlite3VtabRollback()
1072   ** call will do so. We need to do this before the check for active
1073   ** SQL statements below, as the v-table implementation may be storing
1074   ** some prepared statements internally.
1075   */
1076   sqlite3VtabRollback(db);
1077 
1078   /* Legacy behavior (sqlite3_close() behavior) is to return
1079   ** SQLITE_BUSY if the connection can not be closed immediately.
1080   */
1081   if( !forceZombie && connectionIsBusy(db) ){
1082     sqlite3ErrorWithMsg(db, SQLITE_BUSY, "unable to close due to unfinalized "
1083        "statements or unfinished backups");
1084     sqlite3_mutex_leave(db->mutex);
1085     return SQLITE_BUSY;
1086   }
1087 
1088 #ifdef SQLITE_ENABLE_SQLLOG
1089   if( sqlite3GlobalConfig.xSqllog ){
1090     /* Closing the handle. Fourth parameter is passed the value 2. */
1091     sqlite3GlobalConfig.xSqllog(sqlite3GlobalConfig.pSqllogArg, db, 0, 2);
1092   }
1093 #endif
1094 
1095   /* Convert the connection into a zombie and then close it.
1096   */
1097   db->magic = SQLITE_MAGIC_ZOMBIE;
1098   sqlite3LeaveMutexAndCloseZombie(db);
1099   return SQLITE_OK;
1100 }
1101 
1102 /*
1103 ** Two variations on the public interface for closing a database
1104 ** connection. The sqlite3_close() version returns SQLITE_BUSY and
1105 ** leaves the connection option if there are unfinalized prepared
1106 ** statements or unfinished sqlite3_backups.  The sqlite3_close_v2()
1107 ** version forces the connection to become a zombie if there are
1108 ** unclosed resources, and arranges for deallocation when the last
1109 ** prepare statement or sqlite3_backup closes.
1110 */
1111 int sqlite3_close(sqlite3 *db){ return sqlite3Close(db,0); }
1112 int sqlite3_close_v2(sqlite3 *db){ return sqlite3Close(db,1); }
1113 
1114 
1115 /*
1116 ** Close the mutex on database connection db.
1117 **
1118 ** Furthermore, if database connection db is a zombie (meaning that there
1119 ** has been a prior call to sqlite3_close(db) or sqlite3_close_v2(db)) and
1120 ** every sqlite3_stmt has now been finalized and every sqlite3_backup has
1121 ** finished, then free all resources.
1122 */
1123 void sqlite3LeaveMutexAndCloseZombie(sqlite3 *db){
1124   HashElem *i;                    /* Hash table iterator */
1125   int j;
1126 
1127   /* If there are outstanding sqlite3_stmt or sqlite3_backup objects
1128   ** or if the connection has not yet been closed by sqlite3_close_v2(),
1129   ** then just leave the mutex and return.
1130   */
1131   if( db->magic!=SQLITE_MAGIC_ZOMBIE || connectionIsBusy(db) ){
1132     sqlite3_mutex_leave(db->mutex);
1133     return;
1134   }
1135 
1136   /* If we reach this point, it means that the database connection has
1137   ** closed all sqlite3_stmt and sqlite3_backup objects and has been
1138   ** passed to sqlite3_close (meaning that it is a zombie).  Therefore,
1139   ** go ahead and free all resources.
1140   */
1141 
1142   /* If a transaction is open, roll it back. This also ensures that if
1143   ** any database schemas have been modified by an uncommitted transaction
1144   ** they are reset. And that the required b-tree mutex is held to make
1145   ** the pager rollback and schema reset an atomic operation. */
1146   sqlite3RollbackAll(db, SQLITE_OK);
1147 
1148   /* Free any outstanding Savepoint structures. */
1149   sqlite3CloseSavepoints(db);
1150 
1151   /* Close all database connections */
1152   for(j=0; j<db->nDb; j++){
1153     struct Db *pDb = &db->aDb[j];
1154     if( pDb->pBt ){
1155       sqlite3BtreeClose(pDb->pBt);
1156       pDb->pBt = 0;
1157       if( j!=1 ){
1158         pDb->pSchema = 0;
1159       }
1160     }
1161   }
1162   /* Clear the TEMP schema separately and last */
1163   if( db->aDb[1].pSchema ){
1164     sqlite3SchemaClear(db->aDb[1].pSchema);
1165   }
1166   sqlite3VtabUnlockList(db);
1167 
1168   /* Free up the array of auxiliary databases */
1169   sqlite3CollapseDatabaseArray(db);
1170   assert( db->nDb<=2 );
1171   assert( db->aDb==db->aDbStatic );
1172 
1173   /* Tell the code in notify.c that the connection no longer holds any
1174   ** locks and does not require any further unlock-notify callbacks.
1175   */
1176   sqlite3ConnectionClosed(db);
1177 
1178   for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
1179     FuncDef *pNext, *p;
1180     p = sqliteHashData(i);
1181     do{
1182       functionDestroy(db, p);
1183       pNext = p->pNext;
1184       sqlite3DbFree(db, p);
1185       p = pNext;
1186     }while( p );
1187   }
1188   sqlite3HashClear(&db->aFunc);
1189   for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
1190     CollSeq *pColl = (CollSeq *)sqliteHashData(i);
1191     /* Invoke any destructors registered for collation sequence user data. */
1192     for(j=0; j<3; j++){
1193       if( pColl[j].xDel ){
1194         pColl[j].xDel(pColl[j].pUser);
1195       }
1196     }
1197     sqlite3DbFree(db, pColl);
1198   }
1199   sqlite3HashClear(&db->aCollSeq);
1200 #ifndef SQLITE_OMIT_VIRTUALTABLE
1201   for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
1202     Module *pMod = (Module *)sqliteHashData(i);
1203     if( pMod->xDestroy ){
1204       pMod->xDestroy(pMod->pAux);
1205     }
1206     sqlite3VtabEponymousTableClear(db, pMod);
1207     sqlite3DbFree(db, pMod);
1208   }
1209   sqlite3HashClear(&db->aModule);
1210 #endif
1211 
1212   sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
1213   sqlite3ValueFree(db->pErr);
1214   sqlite3CloseExtensions(db);
1215 #if SQLITE_USER_AUTHENTICATION
1216   sqlite3_free(db->auth.zAuthUser);
1217   sqlite3_free(db->auth.zAuthPW);
1218 #endif
1219 
1220   db->magic = SQLITE_MAGIC_ERROR;
1221 
1222   /* The temp-database schema is allocated differently from the other schema
1223   ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
1224   ** So it needs to be freed here. Todo: Why not roll the temp schema into
1225   ** the same sqliteMalloc() as the one that allocates the database
1226   ** structure?
1227   */
1228   sqlite3DbFree(db, db->aDb[1].pSchema);
1229   sqlite3_mutex_leave(db->mutex);
1230   db->magic = SQLITE_MAGIC_CLOSED;
1231   sqlite3_mutex_free(db->mutex);
1232   assert( db->lookaside.nOut==0 );  /* Fails on a lookaside memory leak */
1233   if( db->lookaside.bMalloced ){
1234     sqlite3_free(db->lookaside.pStart);
1235   }
1236   sqlite3_free(db);
1237 }
1238 
1239 /*
1240 ** Rollback all database files.  If tripCode is not SQLITE_OK, then
1241 ** any write cursors are invalidated ("tripped" - as in "tripping a circuit
1242 ** breaker") and made to return tripCode if there are any further
1243 ** attempts to use that cursor.  Read cursors remain open and valid
1244 ** but are "saved" in case the table pages are moved around.
1245 */
1246 void sqlite3RollbackAll(sqlite3 *db, int tripCode){
1247   int i;
1248   int inTrans = 0;
1249   int schemaChange;
1250   assert( sqlite3_mutex_held(db->mutex) );
1251   sqlite3BeginBenignMalloc();
1252 
1253   /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
1254   ** This is important in case the transaction being rolled back has
1255   ** modified the database schema. If the b-tree mutexes are not taken
1256   ** here, then another shared-cache connection might sneak in between
1257   ** the database rollback and schema reset, which can cause false
1258   ** corruption reports in some cases.  */
1259   sqlite3BtreeEnterAll(db);
1260   schemaChange = (db->flags & SQLITE_InternChanges)!=0 && db->init.busy==0;
1261 
1262   for(i=0; i<db->nDb; i++){
1263     Btree *p = db->aDb[i].pBt;
1264     if( p ){
1265       if( sqlite3BtreeIsInTrans(p) ){
1266         inTrans = 1;
1267       }
1268       sqlite3BtreeRollback(p, tripCode, !schemaChange);
1269     }
1270   }
1271   sqlite3VtabRollback(db);
1272   sqlite3EndBenignMalloc();
1273 
1274   if( (db->flags&SQLITE_InternChanges)!=0 && db->init.busy==0 ){
1275     sqlite3ExpirePreparedStatements(db);
1276     sqlite3ResetAllSchemasOfConnection(db);
1277   }
1278   sqlite3BtreeLeaveAll(db);
1279 
1280   /* Any deferred constraint violations have now been resolved. */
1281   db->nDeferredCons = 0;
1282   db->nDeferredImmCons = 0;
1283   db->flags &= ~SQLITE_DeferFKs;
1284 
1285   /* If one has been configured, invoke the rollback-hook callback */
1286   if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
1287     db->xRollbackCallback(db->pRollbackArg);
1288   }
1289 }
1290 
1291 /*
1292 ** Return a static string containing the name corresponding to the error code
1293 ** specified in the argument.
1294 */
1295 #if defined(SQLITE_NEED_ERR_NAME)
1296 const char *sqlite3ErrName(int rc){
1297   const char *zName = 0;
1298   int i, origRc = rc;
1299   for(i=0; i<2 && zName==0; i++, rc &= 0xff){
1300     switch( rc ){
1301       case SQLITE_OK:                 zName = "SQLITE_OK";                break;
1302       case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
1303       case SQLITE_INTERNAL:           zName = "SQLITE_INTERNAL";          break;
1304       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
1305       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
1306       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
1307       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
1308       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
1309       case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
1310       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
1311       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
1312       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
1313       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
1314       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;
1315       case SQLITE_READONLY_CANTLOCK:  zName = "SQLITE_READONLY_CANTLOCK"; break;
1316       case SQLITE_READONLY_ROLLBACK:  zName = "SQLITE_READONLY_ROLLBACK"; break;
1317       case SQLITE_READONLY_DBMOVED:   zName = "SQLITE_READONLY_DBMOVED";  break;
1318       case SQLITE_INTERRUPT:          zName = "SQLITE_INTERRUPT";         break;
1319       case SQLITE_IOERR:              zName = "SQLITE_IOERR";             break;
1320       case SQLITE_IOERR_READ:         zName = "SQLITE_IOERR_READ";        break;
1321       case SQLITE_IOERR_SHORT_READ:   zName = "SQLITE_IOERR_SHORT_READ";  break;
1322       case SQLITE_IOERR_WRITE:        zName = "SQLITE_IOERR_WRITE";       break;
1323       case SQLITE_IOERR_FSYNC:        zName = "SQLITE_IOERR_FSYNC";       break;
1324       case SQLITE_IOERR_DIR_FSYNC:    zName = "SQLITE_IOERR_DIR_FSYNC";   break;
1325       case SQLITE_IOERR_TRUNCATE:     zName = "SQLITE_IOERR_TRUNCATE";    break;
1326       case SQLITE_IOERR_FSTAT:        zName = "SQLITE_IOERR_FSTAT";       break;
1327       case SQLITE_IOERR_UNLOCK:       zName = "SQLITE_IOERR_UNLOCK";      break;
1328       case SQLITE_IOERR_RDLOCK:       zName = "SQLITE_IOERR_RDLOCK";      break;
1329       case SQLITE_IOERR_DELETE:       zName = "SQLITE_IOERR_DELETE";      break;
1330       case SQLITE_IOERR_NOMEM:        zName = "SQLITE_IOERR_NOMEM";       break;
1331       case SQLITE_IOERR_ACCESS:       zName = "SQLITE_IOERR_ACCESS";      break;
1332       case SQLITE_IOERR_CHECKRESERVEDLOCK:
1333                                 zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
1334       case SQLITE_IOERR_LOCK:         zName = "SQLITE_IOERR_LOCK";        break;
1335       case SQLITE_IOERR_CLOSE:        zName = "SQLITE_IOERR_CLOSE";       break;
1336       case SQLITE_IOERR_DIR_CLOSE:    zName = "SQLITE_IOERR_DIR_CLOSE";   break;
1337       case SQLITE_IOERR_SHMOPEN:      zName = "SQLITE_IOERR_SHMOPEN";     break;
1338       case SQLITE_IOERR_SHMSIZE:      zName = "SQLITE_IOERR_SHMSIZE";     break;
1339       case SQLITE_IOERR_SHMLOCK:      zName = "SQLITE_IOERR_SHMLOCK";     break;
1340       case SQLITE_IOERR_SHMMAP:       zName = "SQLITE_IOERR_SHMMAP";      break;
1341       case SQLITE_IOERR_SEEK:         zName = "SQLITE_IOERR_SEEK";        break;
1342       case SQLITE_IOERR_DELETE_NOENT: zName = "SQLITE_IOERR_DELETE_NOENT";break;
1343       case SQLITE_IOERR_MMAP:         zName = "SQLITE_IOERR_MMAP";        break;
1344       case SQLITE_IOERR_GETTEMPPATH:  zName = "SQLITE_IOERR_GETTEMPPATH"; break;
1345       case SQLITE_IOERR_CONVPATH:     zName = "SQLITE_IOERR_CONVPATH";    break;
1346       case SQLITE_CORRUPT:            zName = "SQLITE_CORRUPT";           break;
1347       case SQLITE_CORRUPT_VTAB:       zName = "SQLITE_CORRUPT_VTAB";      break;
1348       case SQLITE_NOTFOUND:           zName = "SQLITE_NOTFOUND";          break;
1349       case SQLITE_FULL:               zName = "SQLITE_FULL";              break;
1350       case SQLITE_CANTOPEN:           zName = "SQLITE_CANTOPEN";          break;
1351       case SQLITE_CANTOPEN_NOTEMPDIR: zName = "SQLITE_CANTOPEN_NOTEMPDIR";break;
1352       case SQLITE_CANTOPEN_ISDIR:     zName = "SQLITE_CANTOPEN_ISDIR";    break;
1353       case SQLITE_CANTOPEN_FULLPATH:  zName = "SQLITE_CANTOPEN_FULLPATH"; break;
1354       case SQLITE_CANTOPEN_CONVPATH:  zName = "SQLITE_CANTOPEN_CONVPATH"; break;
1355       case SQLITE_PROTOCOL:           zName = "SQLITE_PROTOCOL";          break;
1356       case SQLITE_EMPTY:              zName = "SQLITE_EMPTY";             break;
1357       case SQLITE_SCHEMA:             zName = "SQLITE_SCHEMA";            break;
1358       case SQLITE_TOOBIG:             zName = "SQLITE_TOOBIG";            break;
1359       case SQLITE_CONSTRAINT:         zName = "SQLITE_CONSTRAINT";        break;
1360       case SQLITE_CONSTRAINT_UNIQUE:  zName = "SQLITE_CONSTRAINT_UNIQUE"; break;
1361       case SQLITE_CONSTRAINT_TRIGGER: zName = "SQLITE_CONSTRAINT_TRIGGER";break;
1362       case SQLITE_CONSTRAINT_FOREIGNKEY:
1363                                 zName = "SQLITE_CONSTRAINT_FOREIGNKEY";   break;
1364       case SQLITE_CONSTRAINT_CHECK:   zName = "SQLITE_CONSTRAINT_CHECK";  break;
1365       case SQLITE_CONSTRAINT_PRIMARYKEY:
1366                                 zName = "SQLITE_CONSTRAINT_PRIMARYKEY";   break;
1367       case SQLITE_CONSTRAINT_NOTNULL: zName = "SQLITE_CONSTRAINT_NOTNULL";break;
1368       case SQLITE_CONSTRAINT_COMMITHOOK:
1369                                 zName = "SQLITE_CONSTRAINT_COMMITHOOK";   break;
1370       case SQLITE_CONSTRAINT_VTAB:    zName = "SQLITE_CONSTRAINT_VTAB";   break;
1371       case SQLITE_CONSTRAINT_FUNCTION:
1372                                 zName = "SQLITE_CONSTRAINT_FUNCTION";     break;
1373       case SQLITE_CONSTRAINT_ROWID:   zName = "SQLITE_CONSTRAINT_ROWID";  break;
1374       case SQLITE_MISMATCH:           zName = "SQLITE_MISMATCH";          break;
1375       case SQLITE_MISUSE:             zName = "SQLITE_MISUSE";            break;
1376       case SQLITE_NOLFS:              zName = "SQLITE_NOLFS";             break;
1377       case SQLITE_AUTH:               zName = "SQLITE_AUTH";              break;
1378       case SQLITE_FORMAT:             zName = "SQLITE_FORMAT";            break;
1379       case SQLITE_RANGE:              zName = "SQLITE_RANGE";             break;
1380       case SQLITE_NOTADB:             zName = "SQLITE_NOTADB";            break;
1381       case SQLITE_ROW:                zName = "SQLITE_ROW";               break;
1382       case SQLITE_NOTICE:             zName = "SQLITE_NOTICE";            break;
1383       case SQLITE_NOTICE_RECOVER_WAL: zName = "SQLITE_NOTICE_RECOVER_WAL";break;
1384       case SQLITE_NOTICE_RECOVER_ROLLBACK:
1385                                 zName = "SQLITE_NOTICE_RECOVER_ROLLBACK"; break;
1386       case SQLITE_WARNING:            zName = "SQLITE_WARNING";           break;
1387       case SQLITE_WARNING_AUTOINDEX:  zName = "SQLITE_WARNING_AUTOINDEX"; break;
1388       case SQLITE_DONE:               zName = "SQLITE_DONE";              break;
1389     }
1390   }
1391   if( zName==0 ){
1392     static char zBuf[50];
1393     sqlite3_snprintf(sizeof(zBuf), zBuf, "SQLITE_UNKNOWN(%d)", origRc);
1394     zName = zBuf;
1395   }
1396   return zName;
1397 }
1398 #endif
1399 
1400 /*
1401 ** Return a static string that describes the kind of error specified in the
1402 ** argument.
1403 */
1404 const char *sqlite3ErrStr(int rc){
1405   static const char* const aMsg[] = {
1406     /* SQLITE_OK          */ "not an error",
1407     /* SQLITE_ERROR       */ "SQL logic error",
1408     /* SQLITE_INTERNAL    */ 0,
1409     /* SQLITE_PERM        */ "access permission denied",
1410     /* SQLITE_ABORT       */ "query aborted",
1411     /* SQLITE_BUSY        */ "database is locked",
1412     /* SQLITE_LOCKED      */ "database table is locked",
1413     /* SQLITE_NOMEM       */ "out of memory",
1414     /* SQLITE_READONLY    */ "attempt to write a readonly database",
1415     /* SQLITE_INTERRUPT   */ "interrupted",
1416     /* SQLITE_IOERR       */ "disk I/O error",
1417     /* SQLITE_CORRUPT     */ "database disk image is malformed",
1418     /* SQLITE_NOTFOUND    */ "unknown operation",
1419     /* SQLITE_FULL        */ "database or disk is full",
1420     /* SQLITE_CANTOPEN    */ "unable to open database file",
1421     /* SQLITE_PROTOCOL    */ "locking protocol",
1422     /* SQLITE_EMPTY       */ 0,
1423     /* SQLITE_SCHEMA      */ "database schema has changed",
1424     /* SQLITE_TOOBIG      */ "string or blob too big",
1425     /* SQLITE_CONSTRAINT  */ "constraint failed",
1426     /* SQLITE_MISMATCH    */ "datatype mismatch",
1427     /* SQLITE_MISUSE      */ "bad parameter or other API misuse",
1428 #ifdef SQLITE_DISABLE_LFS
1429     /* SQLITE_NOLFS       */ "large file support is disabled",
1430 #else
1431     /* SQLITE_NOLFS       */ 0,
1432 #endif
1433     /* SQLITE_AUTH        */ "authorization denied",
1434     /* SQLITE_FORMAT      */ 0,
1435     /* SQLITE_RANGE       */ "column index out of range",
1436     /* SQLITE_NOTADB      */ "file is not a database",
1437   };
1438   const char *zErr = "unknown error";
1439   switch( rc ){
1440     case SQLITE_ABORT_ROLLBACK: {
1441       zErr = "abort due to ROLLBACK";
1442       break;
1443     }
1444     default: {
1445       rc &= 0xff;
1446       if( ALWAYS(rc>=0) && rc<ArraySize(aMsg) && aMsg[rc]!=0 ){
1447         zErr = aMsg[rc];
1448       }
1449       break;
1450     }
1451   }
1452   return zErr;
1453 }
1454 
1455 /*
1456 ** This routine implements a busy callback that sleeps and tries
1457 ** again until a timeout value is reached.  The timeout value is
1458 ** an integer number of milliseconds passed in as the first
1459 ** argument.
1460 */
1461 static int sqliteDefaultBusyCallback(
1462  void *ptr,               /* Database connection */
1463  int count                /* Number of times table has been busy */
1464 ){
1465 #if SQLITE_OS_WIN || HAVE_USLEEP
1466   static const u8 delays[] =
1467      { 1, 2, 5, 10, 15, 20, 25, 25,  25,  50,  50, 100 };
1468   static const u8 totals[] =
1469      { 0, 1, 3,  8, 18, 33, 53, 78, 103, 128, 178, 228 };
1470 # define NDELAY ArraySize(delays)
1471   sqlite3 *db = (sqlite3 *)ptr;
1472   int timeout = db->busyTimeout;
1473   int delay, prior;
1474 
1475   assert( count>=0 );
1476   if( count < NDELAY ){
1477     delay = delays[count];
1478     prior = totals[count];
1479   }else{
1480     delay = delays[NDELAY-1];
1481     prior = totals[NDELAY-1] + delay*(count-(NDELAY-1));
1482   }
1483   if( prior + delay > timeout ){
1484     delay = timeout - prior;
1485     if( delay<=0 ) return 0;
1486   }
1487   sqlite3OsSleep(db->pVfs, delay*1000);
1488   return 1;
1489 #else
1490   sqlite3 *db = (sqlite3 *)ptr;
1491   int timeout = ((sqlite3 *)ptr)->busyTimeout;
1492   if( (count+1)*1000 > timeout ){
1493     return 0;
1494   }
1495   sqlite3OsSleep(db->pVfs, 1000000);
1496   return 1;
1497 #endif
1498 }
1499 
1500 /*
1501 ** Invoke the given busy handler.
1502 **
1503 ** This routine is called when an operation failed with a lock.
1504 ** If this routine returns non-zero, the lock is retried.  If it
1505 ** returns 0, the operation aborts with an SQLITE_BUSY error.
1506 */
1507 int sqlite3InvokeBusyHandler(BusyHandler *p){
1508   int rc;
1509   if( NEVER(p==0) || p->xFunc==0 || p->nBusy<0 ) return 0;
1510   rc = p->xFunc(p->pArg, p->nBusy);
1511   if( rc==0 ){
1512     p->nBusy = -1;
1513   }else{
1514     p->nBusy++;
1515   }
1516   return rc;
1517 }
1518 
1519 /*
1520 ** This routine sets the busy callback for an Sqlite database to the
1521 ** given callback function with the given argument.
1522 */
1523 int sqlite3_busy_handler(
1524   sqlite3 *db,
1525   int (*xBusy)(void*,int),
1526   void *pArg
1527 ){
1528 #ifdef SQLITE_ENABLE_API_ARMOR
1529   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1530 #endif
1531   sqlite3_mutex_enter(db->mutex);
1532   db->busyHandler.xFunc = xBusy;
1533   db->busyHandler.pArg = pArg;
1534   db->busyHandler.nBusy = 0;
1535   db->busyTimeout = 0;
1536   sqlite3_mutex_leave(db->mutex);
1537   return SQLITE_OK;
1538 }
1539 
1540 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
1541 /*
1542 ** This routine sets the progress callback for an Sqlite database to the
1543 ** given callback function with the given argument. The progress callback will
1544 ** be invoked every nOps opcodes.
1545 */
1546 void sqlite3_progress_handler(
1547   sqlite3 *db,
1548   int nOps,
1549   int (*xProgress)(void*),
1550   void *pArg
1551 ){
1552 #ifdef SQLITE_ENABLE_API_ARMOR
1553   if( !sqlite3SafetyCheckOk(db) ){
1554     (void)SQLITE_MISUSE_BKPT;
1555     return;
1556   }
1557 #endif
1558   sqlite3_mutex_enter(db->mutex);
1559   if( nOps>0 ){
1560     db->xProgress = xProgress;
1561     db->nProgressOps = (unsigned)nOps;
1562     db->pProgressArg = pArg;
1563   }else{
1564     db->xProgress = 0;
1565     db->nProgressOps = 0;
1566     db->pProgressArg = 0;
1567   }
1568   sqlite3_mutex_leave(db->mutex);
1569 }
1570 #endif
1571 
1572 
1573 /*
1574 ** This routine installs a default busy handler that waits for the
1575 ** specified number of milliseconds before returning 0.
1576 */
1577 int sqlite3_busy_timeout(sqlite3 *db, int ms){
1578 #ifdef SQLITE_ENABLE_API_ARMOR
1579   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
1580 #endif
1581   if( ms>0 ){
1582     sqlite3_busy_handler(db, sqliteDefaultBusyCallback, (void*)db);
1583     db->busyTimeout = ms;
1584   }else{
1585     sqlite3_busy_handler(db, 0, 0);
1586   }
1587   return SQLITE_OK;
1588 }
1589 
1590 /*
1591 ** Cause any pending operation to stop at its earliest opportunity.
1592 */
1593 void sqlite3_interrupt(sqlite3 *db){
1594 #ifdef SQLITE_ENABLE_API_ARMOR
1595   if( !sqlite3SafetyCheckOk(db) && (db==0 || db->magic!=SQLITE_MAGIC_ZOMBIE) ){
1596     (void)SQLITE_MISUSE_BKPT;
1597     return;
1598   }
1599 #endif
1600   db->u1.isInterrupted = 1;
1601 }
1602 
1603 
1604 /*
1605 ** This function is exactly the same as sqlite3_create_function(), except
1606 ** that it is designed to be called by internal code. The difference is
1607 ** that if a malloc() fails in sqlite3_create_function(), an error code
1608 ** is returned and the mallocFailed flag cleared.
1609 */
1610 int sqlite3CreateFunc(
1611   sqlite3 *db,
1612   const char *zFunctionName,
1613   int nArg,
1614   int enc,
1615   void *pUserData,
1616   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1617   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1618   void (*xFinal)(sqlite3_context*),
1619   FuncDestructor *pDestructor
1620 ){
1621   FuncDef *p;
1622   int nName;
1623   int extraFlags;
1624 
1625   assert( sqlite3_mutex_held(db->mutex) );
1626   if( zFunctionName==0 ||
1627       (xSFunc && (xFinal || xStep)) ||
1628       (!xSFunc && (xFinal && !xStep)) ||
1629       (!xSFunc && (!xFinal && xStep)) ||
1630       (nArg<-1 || nArg>SQLITE_MAX_FUNCTION_ARG) ||
1631       (255<(nName = sqlite3Strlen30( zFunctionName))) ){
1632     return SQLITE_MISUSE_BKPT;
1633   }
1634 
1635   assert( SQLITE_FUNC_CONSTANT==SQLITE_DETERMINISTIC );
1636   extraFlags = enc &  SQLITE_DETERMINISTIC;
1637   enc &= (SQLITE_FUNC_ENCMASK|SQLITE_ANY);
1638 
1639 #ifndef SQLITE_OMIT_UTF16
1640   /* If SQLITE_UTF16 is specified as the encoding type, transform this
1641   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
1642   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
1643   **
1644   ** If SQLITE_ANY is specified, add three versions of the function
1645   ** to the hash table.
1646   */
1647   if( enc==SQLITE_UTF16 ){
1648     enc = SQLITE_UTF16NATIVE;
1649   }else if( enc==SQLITE_ANY ){
1650     int rc;
1651     rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF8|extraFlags,
1652          pUserData, xSFunc, xStep, xFinal, pDestructor);
1653     if( rc==SQLITE_OK ){
1654       rc = sqlite3CreateFunc(db, zFunctionName, nArg, SQLITE_UTF16LE|extraFlags,
1655           pUserData, xSFunc, xStep, xFinal, pDestructor);
1656     }
1657     if( rc!=SQLITE_OK ){
1658       return rc;
1659     }
1660     enc = SQLITE_UTF16BE;
1661   }
1662 #else
1663   enc = SQLITE_UTF8;
1664 #endif
1665 
1666   /* Check if an existing function is being overridden or deleted. If so,
1667   ** and there are active VMs, then return SQLITE_BUSY. If a function
1668   ** is being overridden/deleted but there are no active VMs, allow the
1669   ** operation to continue but invalidate all precompiled statements.
1670   */
1671   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 0);
1672   if( p && (p->funcFlags & SQLITE_FUNC_ENCMASK)==enc && p->nArg==nArg ){
1673     if( db->nVdbeActive ){
1674       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
1675         "unable to delete/modify user-function due to active statements");
1676       assert( !db->mallocFailed );
1677       return SQLITE_BUSY;
1678     }else{
1679       sqlite3ExpirePreparedStatements(db);
1680     }
1681   }
1682 
1683   p = sqlite3FindFunction(db, zFunctionName, nArg, (u8)enc, 1);
1684   assert(p || db->mallocFailed);
1685   if( !p ){
1686     return SQLITE_NOMEM_BKPT;
1687   }
1688 
1689   /* If an older version of the function with a configured destructor is
1690   ** being replaced invoke the destructor function here. */
1691   functionDestroy(db, p);
1692 
1693   if( pDestructor ){
1694     pDestructor->nRef++;
1695   }
1696   p->u.pDestructor = pDestructor;
1697   p->funcFlags = (p->funcFlags & SQLITE_FUNC_ENCMASK) | extraFlags;
1698   testcase( p->funcFlags & SQLITE_DETERMINISTIC );
1699   p->xSFunc = xSFunc ? xSFunc : xStep;
1700   p->xFinalize = xFinal;
1701   p->pUserData = pUserData;
1702   p->nArg = (u16)nArg;
1703   return SQLITE_OK;
1704 }
1705 
1706 /*
1707 ** Create new user functions.
1708 */
1709 int sqlite3_create_function(
1710   sqlite3 *db,
1711   const char *zFunc,
1712   int nArg,
1713   int enc,
1714   void *p,
1715   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1716   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1717   void (*xFinal)(sqlite3_context*)
1718 ){
1719   return sqlite3_create_function_v2(db, zFunc, nArg, enc, p, xSFunc, xStep,
1720                                     xFinal, 0);
1721 }
1722 
1723 int sqlite3_create_function_v2(
1724   sqlite3 *db,
1725   const char *zFunc,
1726   int nArg,
1727   int enc,
1728   void *p,
1729   void (*xSFunc)(sqlite3_context*,int,sqlite3_value **),
1730   void (*xStep)(sqlite3_context*,int,sqlite3_value **),
1731   void (*xFinal)(sqlite3_context*),
1732   void (*xDestroy)(void *)
1733 ){
1734   int rc = SQLITE_ERROR;
1735   FuncDestructor *pArg = 0;
1736 
1737 #ifdef SQLITE_ENABLE_API_ARMOR
1738   if( !sqlite3SafetyCheckOk(db) ){
1739     return SQLITE_MISUSE_BKPT;
1740   }
1741 #endif
1742   sqlite3_mutex_enter(db->mutex);
1743   if( xDestroy ){
1744     pArg = (FuncDestructor *)sqlite3DbMallocZero(db, sizeof(FuncDestructor));
1745     if( !pArg ){
1746       xDestroy(p);
1747       goto out;
1748     }
1749     pArg->xDestroy = xDestroy;
1750     pArg->pUserData = p;
1751   }
1752   rc = sqlite3CreateFunc(db, zFunc, nArg, enc, p, xSFunc, xStep, xFinal, pArg);
1753   if( pArg && pArg->nRef==0 ){
1754     assert( rc!=SQLITE_OK );
1755     xDestroy(p);
1756     sqlite3DbFree(db, pArg);
1757   }
1758 
1759  out:
1760   rc = sqlite3ApiExit(db, rc);
1761   sqlite3_mutex_leave(db->mutex);
1762   return rc;
1763 }
1764 
1765 #ifndef SQLITE_OMIT_UTF16
1766 int sqlite3_create_function16(
1767   sqlite3 *db,
1768   const void *zFunctionName,
1769   int nArg,
1770   int eTextRep,
1771   void *p,
1772   void (*xSFunc)(sqlite3_context*,int,sqlite3_value**),
1773   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1774   void (*xFinal)(sqlite3_context*)
1775 ){
1776   int rc;
1777   char *zFunc8;
1778 
1779 #ifdef SQLITE_ENABLE_API_ARMOR
1780   if( !sqlite3SafetyCheckOk(db) || zFunctionName==0 ) return SQLITE_MISUSE_BKPT;
1781 #endif
1782   sqlite3_mutex_enter(db->mutex);
1783   assert( !db->mallocFailed );
1784   zFunc8 = sqlite3Utf16to8(db, zFunctionName, -1, SQLITE_UTF16NATIVE);
1785   rc = sqlite3CreateFunc(db, zFunc8, nArg, eTextRep, p, xSFunc,xStep,xFinal,0);
1786   sqlite3DbFree(db, zFunc8);
1787   rc = sqlite3ApiExit(db, rc);
1788   sqlite3_mutex_leave(db->mutex);
1789   return rc;
1790 }
1791 #endif
1792 
1793 
1794 /*
1795 ** Declare that a function has been overloaded by a virtual table.
1796 **
1797 ** If the function already exists as a regular global function, then
1798 ** this routine is a no-op.  If the function does not exist, then create
1799 ** a new one that always throws a run-time error.
1800 **
1801 ** When virtual tables intend to provide an overloaded function, they
1802 ** should call this routine to make sure the global function exists.
1803 ** A global function must exist in order for name resolution to work
1804 ** properly.
1805 */
1806 int sqlite3_overload_function(
1807   sqlite3 *db,
1808   const char *zName,
1809   int nArg
1810 ){
1811   int rc = SQLITE_OK;
1812 
1813 #ifdef SQLITE_ENABLE_API_ARMOR
1814   if( !sqlite3SafetyCheckOk(db) || zName==0 || nArg<-2 ){
1815     return SQLITE_MISUSE_BKPT;
1816   }
1817 #endif
1818   sqlite3_mutex_enter(db->mutex);
1819   if( sqlite3FindFunction(db, zName, nArg, SQLITE_UTF8, 0)==0 ){
1820     rc = sqlite3CreateFunc(db, zName, nArg, SQLITE_UTF8,
1821                            0, sqlite3InvalidFunction, 0, 0, 0);
1822   }
1823   rc = sqlite3ApiExit(db, rc);
1824   sqlite3_mutex_leave(db->mutex);
1825   return rc;
1826 }
1827 
1828 #ifndef SQLITE_OMIT_TRACE
1829 /*
1830 ** Register a trace function.  The pArg from the previously registered trace
1831 ** is returned.
1832 **
1833 ** A NULL trace function means that no tracing is executes.  A non-NULL
1834 ** trace is a pointer to a function that is invoked at the start of each
1835 ** SQL statement.
1836 */
1837 #ifndef SQLITE_OMIT_DEPRECATED
1838 void *sqlite3_trace(sqlite3 *db, void(*xTrace)(void*,const char*), void *pArg){
1839   void *pOld;
1840 
1841 #ifdef SQLITE_ENABLE_API_ARMOR
1842   if( !sqlite3SafetyCheckOk(db) ){
1843     (void)SQLITE_MISUSE_BKPT;
1844     return 0;
1845   }
1846 #endif
1847   sqlite3_mutex_enter(db->mutex);
1848   pOld = db->pTraceArg;
1849   db->mTrace = xTrace ? SQLITE_TRACE_LEGACY : 0;
1850   db->xTrace = (int(*)(u32,void*,void*,void*))xTrace;
1851   db->pTraceArg = pArg;
1852   sqlite3_mutex_leave(db->mutex);
1853   return pOld;
1854 }
1855 #endif /* SQLITE_OMIT_DEPRECATED */
1856 
1857 /* Register a trace callback using the version-2 interface.
1858 */
1859 int sqlite3_trace_v2(
1860   sqlite3 *db,                               /* Trace this connection */
1861   unsigned mTrace,                           /* Mask of events to be traced */
1862   int(*xTrace)(unsigned,void*,void*,void*),  /* Callback to invoke */
1863   void *pArg                                 /* Context */
1864 ){
1865 #ifdef SQLITE_ENABLE_API_ARMOR
1866   if( !sqlite3SafetyCheckOk(db) ){
1867     return SQLITE_MISUSE_BKPT;
1868   }
1869 #endif
1870   sqlite3_mutex_enter(db->mutex);
1871   if( mTrace==0 ) xTrace = 0;
1872   if( xTrace==0 ) mTrace = 0;
1873   db->mTrace = mTrace;
1874   db->xTrace = xTrace;
1875   db->pTraceArg = pArg;
1876   sqlite3_mutex_leave(db->mutex);
1877   return SQLITE_OK;
1878 }
1879 
1880 #ifndef SQLITE_OMIT_DEPRECATED
1881 /*
1882 ** Register a profile function.  The pArg from the previously registered
1883 ** profile function is returned.
1884 **
1885 ** A NULL profile function means that no profiling is executes.  A non-NULL
1886 ** profile is a pointer to a function that is invoked at the conclusion of
1887 ** each SQL statement that is run.
1888 */
1889 void *sqlite3_profile(
1890   sqlite3 *db,
1891   void (*xProfile)(void*,const char*,sqlite_uint64),
1892   void *pArg
1893 ){
1894   void *pOld;
1895 
1896 #ifdef SQLITE_ENABLE_API_ARMOR
1897   if( !sqlite3SafetyCheckOk(db) ){
1898     (void)SQLITE_MISUSE_BKPT;
1899     return 0;
1900   }
1901 #endif
1902   sqlite3_mutex_enter(db->mutex);
1903   pOld = db->pProfileArg;
1904   db->xProfile = xProfile;
1905   db->pProfileArg = pArg;
1906   sqlite3_mutex_leave(db->mutex);
1907   return pOld;
1908 }
1909 #endif /* SQLITE_OMIT_DEPRECATED */
1910 #endif /* SQLITE_OMIT_TRACE */
1911 
1912 /*
1913 ** Register a function to be invoked when a transaction commits.
1914 ** If the invoked function returns non-zero, then the commit becomes a
1915 ** rollback.
1916 */
1917 void *sqlite3_commit_hook(
1918   sqlite3 *db,              /* Attach the hook to this database */
1919   int (*xCallback)(void*),  /* Function to invoke on each commit */
1920   void *pArg                /* Argument to the function */
1921 ){
1922   void *pOld;
1923 
1924 #ifdef SQLITE_ENABLE_API_ARMOR
1925   if( !sqlite3SafetyCheckOk(db) ){
1926     (void)SQLITE_MISUSE_BKPT;
1927     return 0;
1928   }
1929 #endif
1930   sqlite3_mutex_enter(db->mutex);
1931   pOld = db->pCommitArg;
1932   db->xCommitCallback = xCallback;
1933   db->pCommitArg = pArg;
1934   sqlite3_mutex_leave(db->mutex);
1935   return pOld;
1936 }
1937 
1938 /*
1939 ** Register a callback to be invoked each time a row is updated,
1940 ** inserted or deleted using this database connection.
1941 */
1942 void *sqlite3_update_hook(
1943   sqlite3 *db,              /* Attach the hook to this database */
1944   void (*xCallback)(void*,int,char const *,char const *,sqlite_int64),
1945   void *pArg                /* Argument to the function */
1946 ){
1947   void *pRet;
1948 
1949 #ifdef SQLITE_ENABLE_API_ARMOR
1950   if( !sqlite3SafetyCheckOk(db) ){
1951     (void)SQLITE_MISUSE_BKPT;
1952     return 0;
1953   }
1954 #endif
1955   sqlite3_mutex_enter(db->mutex);
1956   pRet = db->pUpdateArg;
1957   db->xUpdateCallback = xCallback;
1958   db->pUpdateArg = pArg;
1959   sqlite3_mutex_leave(db->mutex);
1960   return pRet;
1961 }
1962 
1963 /*
1964 ** Register a callback to be invoked each time a transaction is rolled
1965 ** back by this database connection.
1966 */
1967 void *sqlite3_rollback_hook(
1968   sqlite3 *db,              /* Attach the hook to this database */
1969   void (*xCallback)(void*), /* Callback function */
1970   void *pArg                /* Argument to the function */
1971 ){
1972   void *pRet;
1973 
1974 #ifdef SQLITE_ENABLE_API_ARMOR
1975   if( !sqlite3SafetyCheckOk(db) ){
1976     (void)SQLITE_MISUSE_BKPT;
1977     return 0;
1978   }
1979 #endif
1980   sqlite3_mutex_enter(db->mutex);
1981   pRet = db->pRollbackArg;
1982   db->xRollbackCallback = xCallback;
1983   db->pRollbackArg = pArg;
1984   sqlite3_mutex_leave(db->mutex);
1985   return pRet;
1986 }
1987 
1988 #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
1989 /*
1990 ** Register a callback to be invoked each time a row is updated,
1991 ** inserted or deleted using this database connection.
1992 */
1993 void *sqlite3_preupdate_hook(
1994   sqlite3 *db,              /* Attach the hook to this database */
1995   void(*xCallback)(         /* Callback function */
1996     void*,sqlite3*,int,char const*,char const*,sqlite3_int64,sqlite3_int64),
1997   void *pArg                /* First callback argument */
1998 ){
1999   void *pRet;
2000   sqlite3_mutex_enter(db->mutex);
2001   pRet = db->pPreUpdateArg;
2002   db->xPreUpdateCallback = xCallback;
2003   db->pPreUpdateArg = pArg;
2004   sqlite3_mutex_leave(db->mutex);
2005   return pRet;
2006 }
2007 #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
2008 
2009 #ifndef SQLITE_OMIT_WAL
2010 /*
2011 ** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
2012 ** Invoke sqlite3_wal_checkpoint if the number of frames in the log file
2013 ** is greater than sqlite3.pWalArg cast to an integer (the value configured by
2014 ** wal_autocheckpoint()).
2015 */
2016 int sqlite3WalDefaultHook(
2017   void *pClientData,     /* Argument */
2018   sqlite3 *db,           /* Connection */
2019   const char *zDb,       /* Database */
2020   int nFrame             /* Size of WAL */
2021 ){
2022   if( nFrame>=SQLITE_PTR_TO_INT(pClientData) ){
2023     sqlite3BeginBenignMalloc();
2024     sqlite3_wal_checkpoint(db, zDb);
2025     sqlite3EndBenignMalloc();
2026   }
2027   return SQLITE_OK;
2028 }
2029 #endif /* SQLITE_OMIT_WAL */
2030 
2031 /*
2032 ** Configure an sqlite3_wal_hook() callback to automatically checkpoint
2033 ** a database after committing a transaction if there are nFrame or
2034 ** more frames in the log file. Passing zero or a negative value as the
2035 ** nFrame parameter disables automatic checkpoints entirely.
2036 **
2037 ** The callback registered by this function replaces any existing callback
2038 ** registered using sqlite3_wal_hook(). Likewise, registering a callback
2039 ** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
2040 ** configured by this function.
2041 */
2042 int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
2043 #ifdef SQLITE_OMIT_WAL
2044   UNUSED_PARAMETER(db);
2045   UNUSED_PARAMETER(nFrame);
2046 #else
2047 #ifdef SQLITE_ENABLE_API_ARMOR
2048   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2049 #endif
2050   if( nFrame>0 ){
2051     sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));
2052   }else{
2053     sqlite3_wal_hook(db, 0, 0);
2054   }
2055 #endif
2056   return SQLITE_OK;
2057 }
2058 
2059 /*
2060 ** Register a callback to be invoked each time a transaction is written
2061 ** into the write-ahead-log by this database connection.
2062 */
2063 void *sqlite3_wal_hook(
2064   sqlite3 *db,                    /* Attach the hook to this db handle */
2065   int(*xCallback)(void *, sqlite3*, const char*, int),
2066   void *pArg                      /* First argument passed to xCallback() */
2067 ){
2068 #ifndef SQLITE_OMIT_WAL
2069   void *pRet;
2070 #ifdef SQLITE_ENABLE_API_ARMOR
2071   if( !sqlite3SafetyCheckOk(db) ){
2072     (void)SQLITE_MISUSE_BKPT;
2073     return 0;
2074   }
2075 #endif
2076   sqlite3_mutex_enter(db->mutex);
2077   pRet = db->pWalArg;
2078   db->xWalCallback = xCallback;
2079   db->pWalArg = pArg;
2080   sqlite3_mutex_leave(db->mutex);
2081   return pRet;
2082 #else
2083   return 0;
2084 #endif
2085 }
2086 
2087 /*
2088 ** Checkpoint database zDb.
2089 */
2090 int sqlite3_wal_checkpoint_v2(
2091   sqlite3 *db,                    /* Database handle */
2092   const char *zDb,                /* Name of attached database (or NULL) */
2093   int eMode,                      /* SQLITE_CHECKPOINT_* value */
2094   int *pnLog,                     /* OUT: Size of WAL log in frames */
2095   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
2096 ){
2097 #ifdef SQLITE_OMIT_WAL
2098   return SQLITE_OK;
2099 #else
2100   int rc;                         /* Return code */
2101   int iDb = SQLITE_MAX_ATTACHED;  /* sqlite3.aDb[] index of db to checkpoint */
2102 
2103 #ifdef SQLITE_ENABLE_API_ARMOR
2104   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
2105 #endif
2106 
2107   /* Initialize the output variables to -1 in case an error occurs. */
2108   if( pnLog ) *pnLog = -1;
2109   if( pnCkpt ) *pnCkpt = -1;
2110 
2111   assert( SQLITE_CHECKPOINT_PASSIVE==0 );
2112   assert( SQLITE_CHECKPOINT_FULL==1 );
2113   assert( SQLITE_CHECKPOINT_RESTART==2 );
2114   assert( SQLITE_CHECKPOINT_TRUNCATE==3 );
2115   if( eMode<SQLITE_CHECKPOINT_PASSIVE || eMode>SQLITE_CHECKPOINT_TRUNCATE ){
2116     /* EVIDENCE-OF: R-03996-12088 The M parameter must be a valid checkpoint
2117     ** mode: */
2118     return SQLITE_MISUSE;
2119   }
2120 
2121   sqlite3_mutex_enter(db->mutex);
2122   if( zDb && zDb[0] ){
2123     iDb = sqlite3FindDbName(db, zDb);
2124   }
2125   if( iDb<0 ){
2126     rc = SQLITE_ERROR;
2127     sqlite3ErrorWithMsg(db, SQLITE_ERROR, "unknown database: %s", zDb);
2128   }else{
2129     db->busyHandler.nBusy = 0;
2130     rc = sqlite3Checkpoint(db, iDb, eMode, pnLog, pnCkpt);
2131     sqlite3Error(db, rc);
2132   }
2133   rc = sqlite3ApiExit(db, rc);
2134 
2135   /* If there are no active statements, clear the interrupt flag at this
2136   ** point.  */
2137   if( db->nVdbeActive==0 ){
2138     db->u1.isInterrupted = 0;
2139   }
2140 
2141   sqlite3_mutex_leave(db->mutex);
2142   return rc;
2143 #endif
2144 }
2145 
2146 
2147 /*
2148 ** Checkpoint database zDb. If zDb is NULL, or if the buffer zDb points
2149 ** to contains a zero-length string, all attached databases are
2150 ** checkpointed.
2151 */
2152 int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
2153   /* EVIDENCE-OF: R-41613-20553 The sqlite3_wal_checkpoint(D,X) is equivalent to
2154   ** sqlite3_wal_checkpoint_v2(D,X,SQLITE_CHECKPOINT_PASSIVE,0,0). */
2155   return sqlite3_wal_checkpoint_v2(db,zDb,SQLITE_CHECKPOINT_PASSIVE,0,0);
2156 }
2157 
2158 #ifndef SQLITE_OMIT_WAL
2159 /*
2160 ** Run a checkpoint on database iDb. This is a no-op if database iDb is
2161 ** not currently open in WAL mode.
2162 **
2163 ** If a transaction is open on the database being checkpointed, this
2164 ** function returns SQLITE_LOCKED and a checkpoint is not attempted. If
2165 ** an error occurs while running the checkpoint, an SQLite error code is
2166 ** returned (i.e. SQLITE_IOERR). Otherwise, SQLITE_OK.
2167 **
2168 ** The mutex on database handle db should be held by the caller. The mutex
2169 ** associated with the specific b-tree being checkpointed is taken by
2170 ** this function while the checkpoint is running.
2171 **
2172 ** If iDb is passed SQLITE_MAX_ATTACHED, then all attached databases are
2173 ** checkpointed. If an error is encountered it is returned immediately -
2174 ** no attempt is made to checkpoint any remaining databases.
2175 **
2176 ** Parameter eMode is one of SQLITE_CHECKPOINT_PASSIVE, FULL or RESTART.
2177 */
2178 int sqlite3Checkpoint(sqlite3 *db, int iDb, int eMode, int *pnLog, int *pnCkpt){
2179   int rc = SQLITE_OK;             /* Return code */
2180   int i;                          /* Used to iterate through attached dbs */
2181   int bBusy = 0;                  /* True if SQLITE_BUSY has been encountered */
2182 
2183   assert( sqlite3_mutex_held(db->mutex) );
2184   assert( !pnLog || *pnLog==-1 );
2185   assert( !pnCkpt || *pnCkpt==-1 );
2186 
2187   for(i=0; i<db->nDb && rc==SQLITE_OK; i++){
2188     if( i==iDb || iDb==SQLITE_MAX_ATTACHED ){
2189       rc = sqlite3BtreeCheckpoint(db->aDb[i].pBt, eMode, pnLog, pnCkpt);
2190       pnLog = 0;
2191       pnCkpt = 0;
2192       if( rc==SQLITE_BUSY ){
2193         bBusy = 1;
2194         rc = SQLITE_OK;
2195       }
2196     }
2197   }
2198 
2199   return (rc==SQLITE_OK && bBusy) ? SQLITE_BUSY : rc;
2200 }
2201 #endif /* SQLITE_OMIT_WAL */
2202 
2203 /*
2204 ** This function returns true if main-memory should be used instead of
2205 ** a temporary file for transient pager files and statement journals.
2206 ** The value returned depends on the value of db->temp_store (runtime
2207 ** parameter) and the compile time value of SQLITE_TEMP_STORE. The
2208 ** following table describes the relationship between these two values
2209 ** and this functions return value.
2210 **
2211 **   SQLITE_TEMP_STORE     db->temp_store     Location of temporary database
2212 **   -----------------     --------------     ------------------------------
2213 **   0                     any                file      (return 0)
2214 **   1                     1                  file      (return 0)
2215 **   1                     2                  memory    (return 1)
2216 **   1                     0                  file      (return 0)
2217 **   2                     1                  file      (return 0)
2218 **   2                     2                  memory    (return 1)
2219 **   2                     0                  memory    (return 1)
2220 **   3                     any                memory    (return 1)
2221 */
2222 int sqlite3TempInMemory(const sqlite3 *db){
2223 #if SQLITE_TEMP_STORE==1
2224   return ( db->temp_store==2 );
2225 #endif
2226 #if SQLITE_TEMP_STORE==2
2227   return ( db->temp_store!=1 );
2228 #endif
2229 #if SQLITE_TEMP_STORE==3
2230   UNUSED_PARAMETER(db);
2231   return 1;
2232 #endif
2233 #if SQLITE_TEMP_STORE<1 || SQLITE_TEMP_STORE>3
2234   UNUSED_PARAMETER(db);
2235   return 0;
2236 #endif
2237 }
2238 
2239 /*
2240 ** Return UTF-8 encoded English language explanation of the most recent
2241 ** error.
2242 */
2243 const char *sqlite3_errmsg(sqlite3 *db){
2244   const char *z;
2245   if( !db ){
2246     return sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2247   }
2248   if( !sqlite3SafetyCheckSickOrOk(db) ){
2249     return sqlite3ErrStr(SQLITE_MISUSE_BKPT);
2250   }
2251   sqlite3_mutex_enter(db->mutex);
2252   if( db->mallocFailed ){
2253     z = sqlite3ErrStr(SQLITE_NOMEM_BKPT);
2254   }else{
2255     testcase( db->pErr==0 );
2256     z = (char*)sqlite3_value_text(db->pErr);
2257     assert( !db->mallocFailed );
2258     if( z==0 ){
2259       z = sqlite3ErrStr(db->errCode);
2260     }
2261   }
2262   sqlite3_mutex_leave(db->mutex);
2263   return z;
2264 }
2265 
2266 #ifndef SQLITE_OMIT_UTF16
2267 /*
2268 ** Return UTF-16 encoded English language explanation of the most recent
2269 ** error.
2270 */
2271 const void *sqlite3_errmsg16(sqlite3 *db){
2272   static const u16 outOfMem[] = {
2273     'o', 'u', 't', ' ', 'o', 'f', ' ', 'm', 'e', 'm', 'o', 'r', 'y', 0
2274   };
2275   static const u16 misuse[] = {
2276     'b', 'a', 'd', ' ', 'p', 'a', 'r', 'a', 'm', 'e', 't', 'e', 'r', ' ',
2277     'o', 'r', ' ', 'o', 't', 'h', 'e', 'r', ' ', 'A', 'P', 'I', ' ',
2278     'm', 'i', 's', 'u', 's', 'e', 0
2279   };
2280 
2281   const void *z;
2282   if( !db ){
2283     return (void *)outOfMem;
2284   }
2285   if( !sqlite3SafetyCheckSickOrOk(db) ){
2286     return (void *)misuse;
2287   }
2288   sqlite3_mutex_enter(db->mutex);
2289   if( db->mallocFailed ){
2290     z = (void *)outOfMem;
2291   }else{
2292     z = sqlite3_value_text16(db->pErr);
2293     if( z==0 ){
2294       sqlite3ErrorWithMsg(db, db->errCode, sqlite3ErrStr(db->errCode));
2295       z = sqlite3_value_text16(db->pErr);
2296     }
2297     /* A malloc() may have failed within the call to sqlite3_value_text16()
2298     ** above. If this is the case, then the db->mallocFailed flag needs to
2299     ** be cleared before returning. Do this directly, instead of via
2300     ** sqlite3ApiExit(), to avoid setting the database handle error message.
2301     */
2302     sqlite3OomClear(db);
2303   }
2304   sqlite3_mutex_leave(db->mutex);
2305   return z;
2306 }
2307 #endif /* SQLITE_OMIT_UTF16 */
2308 
2309 /*
2310 ** Return the most recent error code generated by an SQLite routine. If NULL is
2311 ** passed to this function, we assume a malloc() failed during sqlite3_open().
2312 */
2313 int sqlite3_errcode(sqlite3 *db){
2314   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2315     return SQLITE_MISUSE_BKPT;
2316   }
2317   if( !db || db->mallocFailed ){
2318     return SQLITE_NOMEM_BKPT;
2319   }
2320   return db->errCode & db->errMask;
2321 }
2322 int sqlite3_extended_errcode(sqlite3 *db){
2323   if( db && !sqlite3SafetyCheckSickOrOk(db) ){
2324     return SQLITE_MISUSE_BKPT;
2325   }
2326   if( !db || db->mallocFailed ){
2327     return SQLITE_NOMEM_BKPT;
2328   }
2329   return db->errCode;
2330 }
2331 int sqlite3_system_errno(sqlite3 *db){
2332   return db ? db->iSysErrno : 0;
2333 }
2334 
2335 /*
2336 ** Return a string that describes the kind of error specified in the
2337 ** argument.  For now, this simply calls the internal sqlite3ErrStr()
2338 ** function.
2339 */
2340 const char *sqlite3_errstr(int rc){
2341   return sqlite3ErrStr(rc);
2342 }
2343 
2344 /*
2345 ** Create a new collating function for database "db".  The name is zName
2346 ** and the encoding is enc.
2347 */
2348 static int createCollation(
2349   sqlite3* db,
2350   const char *zName,
2351   u8 enc,
2352   void* pCtx,
2353   int(*xCompare)(void*,int,const void*,int,const void*),
2354   void(*xDel)(void*)
2355 ){
2356   CollSeq *pColl;
2357   int enc2;
2358 
2359   assert( sqlite3_mutex_held(db->mutex) );
2360 
2361   /* If SQLITE_UTF16 is specified as the encoding type, transform this
2362   ** to one of SQLITE_UTF16LE or SQLITE_UTF16BE using the
2363   ** SQLITE_UTF16NATIVE macro. SQLITE_UTF16 is not used internally.
2364   */
2365   enc2 = enc;
2366   testcase( enc2==SQLITE_UTF16 );
2367   testcase( enc2==SQLITE_UTF16_ALIGNED );
2368   if( enc2==SQLITE_UTF16 || enc2==SQLITE_UTF16_ALIGNED ){
2369     enc2 = SQLITE_UTF16NATIVE;
2370   }
2371   if( enc2<SQLITE_UTF8 || enc2>SQLITE_UTF16BE ){
2372     return SQLITE_MISUSE_BKPT;
2373   }
2374 
2375   /* Check if this call is removing or replacing an existing collation
2376   ** sequence. If so, and there are active VMs, return busy. If there
2377   ** are no active VMs, invalidate any pre-compiled statements.
2378   */
2379   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 0);
2380   if( pColl && pColl->xCmp ){
2381     if( db->nVdbeActive ){
2382       sqlite3ErrorWithMsg(db, SQLITE_BUSY,
2383         "unable to delete/modify collation sequence due to active statements");
2384       return SQLITE_BUSY;
2385     }
2386     sqlite3ExpirePreparedStatements(db);
2387 
2388     /* If collation sequence pColl was created directly by a call to
2389     ** sqlite3_create_collation, and not generated by synthCollSeq(),
2390     ** then any copies made by synthCollSeq() need to be invalidated.
2391     ** Also, collation destructor - CollSeq.xDel() - function may need
2392     ** to be called.
2393     */
2394     if( (pColl->enc & ~SQLITE_UTF16_ALIGNED)==enc2 ){
2395       CollSeq *aColl = sqlite3HashFind(&db->aCollSeq, zName);
2396       int j;
2397       for(j=0; j<3; j++){
2398         CollSeq *p = &aColl[j];
2399         if( p->enc==pColl->enc ){
2400           if( p->xDel ){
2401             p->xDel(p->pUser);
2402           }
2403           p->xCmp = 0;
2404         }
2405       }
2406     }
2407   }
2408 
2409   pColl = sqlite3FindCollSeq(db, (u8)enc2, zName, 1);
2410   if( pColl==0 ) return SQLITE_NOMEM_BKPT;
2411   pColl->xCmp = xCompare;
2412   pColl->pUser = pCtx;
2413   pColl->xDel = xDel;
2414   pColl->enc = (u8)(enc2 | (enc & SQLITE_UTF16_ALIGNED));
2415   sqlite3Error(db, SQLITE_OK);
2416   return SQLITE_OK;
2417 }
2418 
2419 
2420 /*
2421 ** This array defines hard upper bounds on limit values.  The
2422 ** initializer must be kept in sync with the SQLITE_LIMIT_*
2423 ** #defines in sqlite3.h.
2424 */
2425 static const int aHardLimit[] = {
2426   SQLITE_MAX_LENGTH,
2427   SQLITE_MAX_SQL_LENGTH,
2428   SQLITE_MAX_COLUMN,
2429   SQLITE_MAX_EXPR_DEPTH,
2430   SQLITE_MAX_COMPOUND_SELECT,
2431   SQLITE_MAX_VDBE_OP,
2432   SQLITE_MAX_FUNCTION_ARG,
2433   SQLITE_MAX_ATTACHED,
2434   SQLITE_MAX_LIKE_PATTERN_LENGTH,
2435   SQLITE_MAX_VARIABLE_NUMBER,      /* IMP: R-38091-32352 */
2436   SQLITE_MAX_TRIGGER_DEPTH,
2437   SQLITE_MAX_WORKER_THREADS,
2438 };
2439 
2440 /*
2441 ** Make sure the hard limits are set to reasonable values
2442 */
2443 #if SQLITE_MAX_LENGTH<100
2444 # error SQLITE_MAX_LENGTH must be at least 100
2445 #endif
2446 #if SQLITE_MAX_SQL_LENGTH<100
2447 # error SQLITE_MAX_SQL_LENGTH must be at least 100
2448 #endif
2449 #if SQLITE_MAX_SQL_LENGTH>SQLITE_MAX_LENGTH
2450 # error SQLITE_MAX_SQL_LENGTH must not be greater than SQLITE_MAX_LENGTH
2451 #endif
2452 #if SQLITE_MAX_COMPOUND_SELECT<2
2453 # error SQLITE_MAX_COMPOUND_SELECT must be at least 2
2454 #endif
2455 #if SQLITE_MAX_VDBE_OP<40
2456 # error SQLITE_MAX_VDBE_OP must be at least 40
2457 #endif
2458 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>127
2459 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 127
2460 #endif
2461 #if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>125
2462 # error SQLITE_MAX_ATTACHED must be between 0 and 125
2463 #endif
2464 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
2465 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
2466 #endif
2467 #if SQLITE_MAX_COLUMN>32767
2468 # error SQLITE_MAX_COLUMN must not exceed 32767
2469 #endif
2470 #if SQLITE_MAX_TRIGGER_DEPTH<1
2471 # error SQLITE_MAX_TRIGGER_DEPTH must be at least 1
2472 #endif
2473 #if SQLITE_MAX_WORKER_THREADS<0 || SQLITE_MAX_WORKER_THREADS>50
2474 # error SQLITE_MAX_WORKER_THREADS must be between 0 and 50
2475 #endif
2476 
2477 
2478 /*
2479 ** Change the value of a limit.  Report the old value.
2480 ** If an invalid limit index is supplied, report -1.
2481 ** Make no changes but still report the old value if the
2482 ** new limit is negative.
2483 **
2484 ** A new lower limit does not shrink existing constructs.
2485 ** It merely prevents new constructs that exceed the limit
2486 ** from forming.
2487 */
2488 int sqlite3_limit(sqlite3 *db, int limitId, int newLimit){
2489   int oldLimit;
2490 
2491 #ifdef SQLITE_ENABLE_API_ARMOR
2492   if( !sqlite3SafetyCheckOk(db) ){
2493     (void)SQLITE_MISUSE_BKPT;
2494     return -1;
2495   }
2496 #endif
2497 
2498   /* EVIDENCE-OF: R-30189-54097 For each limit category SQLITE_LIMIT_NAME
2499   ** there is a hard upper bound set at compile-time by a C preprocessor
2500   ** macro called SQLITE_MAX_NAME. (The "_LIMIT_" in the name is changed to
2501   ** "_MAX_".)
2502   */
2503   assert( aHardLimit[SQLITE_LIMIT_LENGTH]==SQLITE_MAX_LENGTH );
2504   assert( aHardLimit[SQLITE_LIMIT_SQL_LENGTH]==SQLITE_MAX_SQL_LENGTH );
2505   assert( aHardLimit[SQLITE_LIMIT_COLUMN]==SQLITE_MAX_COLUMN );
2506   assert( aHardLimit[SQLITE_LIMIT_EXPR_DEPTH]==SQLITE_MAX_EXPR_DEPTH );
2507   assert( aHardLimit[SQLITE_LIMIT_COMPOUND_SELECT]==SQLITE_MAX_COMPOUND_SELECT);
2508   assert( aHardLimit[SQLITE_LIMIT_VDBE_OP]==SQLITE_MAX_VDBE_OP );
2509   assert( aHardLimit[SQLITE_LIMIT_FUNCTION_ARG]==SQLITE_MAX_FUNCTION_ARG );
2510   assert( aHardLimit[SQLITE_LIMIT_ATTACHED]==SQLITE_MAX_ATTACHED );
2511   assert( aHardLimit[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]==
2512                                                SQLITE_MAX_LIKE_PATTERN_LENGTH );
2513   assert( aHardLimit[SQLITE_LIMIT_VARIABLE_NUMBER]==SQLITE_MAX_VARIABLE_NUMBER);
2514   assert( aHardLimit[SQLITE_LIMIT_TRIGGER_DEPTH]==SQLITE_MAX_TRIGGER_DEPTH );
2515   assert( aHardLimit[SQLITE_LIMIT_WORKER_THREADS]==SQLITE_MAX_WORKER_THREADS );
2516   assert( SQLITE_LIMIT_WORKER_THREADS==(SQLITE_N_LIMIT-1) );
2517 
2518 
2519   if( limitId<0 || limitId>=SQLITE_N_LIMIT ){
2520     return -1;
2521   }
2522   oldLimit = db->aLimit[limitId];
2523   if( newLimit>=0 ){                   /* IMP: R-52476-28732 */
2524     if( newLimit>aHardLimit[limitId] ){
2525       newLimit = aHardLimit[limitId];  /* IMP: R-51463-25634 */
2526     }
2527     db->aLimit[limitId] = newLimit;
2528   }
2529   return oldLimit;                     /* IMP: R-53341-35419 */
2530 }
2531 
2532 /*
2533 ** This function is used to parse both URIs and non-URI filenames passed by the
2534 ** user to API functions sqlite3_open() or sqlite3_open_v2(), and for database
2535 ** URIs specified as part of ATTACH statements.
2536 **
2537 ** The first argument to this function is the name of the VFS to use (or
2538 ** a NULL to signify the default VFS) if the URI does not contain a "vfs=xxx"
2539 ** query parameter. The second argument contains the URI (or non-URI filename)
2540 ** itself. When this function is called the *pFlags variable should contain
2541 ** the default flags to open the database handle with. The value stored in
2542 ** *pFlags may be updated before returning if the URI filename contains
2543 ** "cache=xxx" or "mode=xxx" query parameters.
2544 **
2545 ** If successful, SQLITE_OK is returned. In this case *ppVfs is set to point to
2546 ** the VFS that should be used to open the database file. *pzFile is set to
2547 ** point to a buffer containing the name of the file to open. It is the
2548 ** responsibility of the caller to eventually call sqlite3_free() to release
2549 ** this buffer.
2550 **
2551 ** If an error occurs, then an SQLite error code is returned and *pzErrMsg
2552 ** may be set to point to a buffer containing an English language error
2553 ** message. It is the responsibility of the caller to eventually release
2554 ** this buffer by calling sqlite3_free().
2555 */
2556 int sqlite3ParseUri(
2557   const char *zDefaultVfs,        /* VFS to use if no "vfs=xxx" query option */
2558   const char *zUri,               /* Nul-terminated URI to parse */
2559   unsigned int *pFlags,           /* IN/OUT: SQLITE_OPEN_XXX flags */
2560   sqlite3_vfs **ppVfs,            /* OUT: VFS to use */
2561   char **pzFile,                  /* OUT: Filename component of URI */
2562   char **pzErrMsg                 /* OUT: Error message (if rc!=SQLITE_OK) */
2563 ){
2564   int rc = SQLITE_OK;
2565   unsigned int flags = *pFlags;
2566   const char *zVfs = zDefaultVfs;
2567   char *zFile;
2568   char c;
2569   int nUri = sqlite3Strlen30(zUri);
2570 
2571   assert( *pzErrMsg==0 );
2572 
2573   if( ((flags & SQLITE_OPEN_URI)             /* IMP: R-48725-32206 */
2574             || sqlite3GlobalConfig.bOpenUri) /* IMP: R-51689-46548 */
2575    && nUri>=5 && memcmp(zUri, "file:", 5)==0 /* IMP: R-57884-37496 */
2576   ){
2577     char *zOpt;
2578     int eState;                   /* Parser state when parsing URI */
2579     int iIn;                      /* Input character index */
2580     int iOut = 0;                 /* Output character index */
2581     u64 nByte = nUri+2;           /* Bytes of space to allocate */
2582 
2583     /* Make sure the SQLITE_OPEN_URI flag is set to indicate to the VFS xOpen
2584     ** method that there may be extra parameters following the file-name.  */
2585     flags |= SQLITE_OPEN_URI;
2586 
2587     for(iIn=0; iIn<nUri; iIn++) nByte += (zUri[iIn]=='&');
2588     zFile = sqlite3_malloc64(nByte);
2589     if( !zFile ) return SQLITE_NOMEM_BKPT;
2590 
2591     iIn = 5;
2592 #ifdef SQLITE_ALLOW_URI_AUTHORITY
2593     if( strncmp(zUri+5, "///", 3)==0 ){
2594       iIn = 7;
2595       /* The following condition causes URIs with five leading / characters
2596       ** like file://///host/path to be converted into UNCs like //host/path.
2597       ** The correct URI for that UNC has only two or four leading / characters
2598       ** file://host/path or file:////host/path.  But 5 leading slashes is a
2599       ** common error, we are told, so we handle it as a special case. */
2600       if( strncmp(zUri+7, "///", 3)==0 ){ iIn++; }
2601     }else if( strncmp(zUri+5, "//localhost/", 12)==0 ){
2602       iIn = 16;
2603     }
2604 #else
2605     /* Discard the scheme and authority segments of the URI. */
2606     if( zUri[5]=='/' && zUri[6]=='/' ){
2607       iIn = 7;
2608       while( zUri[iIn] && zUri[iIn]!='/' ) iIn++;
2609       if( iIn!=7 && (iIn!=16 || memcmp("localhost", &zUri[7], 9)) ){
2610         *pzErrMsg = sqlite3_mprintf("invalid uri authority: %.*s",
2611             iIn-7, &zUri[7]);
2612         rc = SQLITE_ERROR;
2613         goto parse_uri_out;
2614       }
2615     }
2616 #endif
2617 
2618     /* Copy the filename and any query parameters into the zFile buffer.
2619     ** Decode %HH escape codes along the way.
2620     **
2621     ** Within this loop, variable eState may be set to 0, 1 or 2, depending
2622     ** on the parsing context. As follows:
2623     **
2624     **   0: Parsing file-name.
2625     **   1: Parsing name section of a name=value query parameter.
2626     **   2: Parsing value section of a name=value query parameter.
2627     */
2628     eState = 0;
2629     while( (c = zUri[iIn])!=0 && c!='#' ){
2630       iIn++;
2631       if( c=='%'
2632        && sqlite3Isxdigit(zUri[iIn])
2633        && sqlite3Isxdigit(zUri[iIn+1])
2634       ){
2635         int octet = (sqlite3HexToInt(zUri[iIn++]) << 4);
2636         octet += sqlite3HexToInt(zUri[iIn++]);
2637 
2638         assert( octet>=0 && octet<256 );
2639         if( octet==0 ){
2640 #ifndef SQLITE_ENABLE_URI_00_ERROR
2641           /* This branch is taken when "%00" appears within the URI. In this
2642           ** case we ignore all text in the remainder of the path, name or
2643           ** value currently being parsed. So ignore the current character
2644           ** and skip to the next "?", "=" or "&", as appropriate. */
2645           while( (c = zUri[iIn])!=0 && c!='#'
2646               && (eState!=0 || c!='?')
2647               && (eState!=1 || (c!='=' && c!='&'))
2648               && (eState!=2 || c!='&')
2649           ){
2650             iIn++;
2651           }
2652           continue;
2653 #else
2654           /* If ENABLE_URI_00_ERROR is defined, "%00" in a URI is an error. */
2655           *pzErrMsg = sqlite3_mprintf("unexpected %%00 in uri");
2656           rc = SQLITE_ERROR;
2657           goto parse_uri_out;
2658 #endif
2659         }
2660         c = octet;
2661       }else if( eState==1 && (c=='&' || c=='=') ){
2662         if( zFile[iOut-1]==0 ){
2663           /* An empty option name. Ignore this option altogether. */
2664           while( zUri[iIn] && zUri[iIn]!='#' && zUri[iIn-1]!='&' ) iIn++;
2665           continue;
2666         }
2667         if( c=='&' ){
2668           zFile[iOut++] = '\0';
2669         }else{
2670           eState = 2;
2671         }
2672         c = 0;
2673       }else if( (eState==0 && c=='?') || (eState==2 && c=='&') ){
2674         c = 0;
2675         eState = 1;
2676       }
2677       zFile[iOut++] = c;
2678     }
2679     if( eState==1 ) zFile[iOut++] = '\0';
2680     zFile[iOut++] = '\0';
2681     zFile[iOut++] = '\0';
2682 
2683     /* Check if there were any options specified that should be interpreted
2684     ** here. Options that are interpreted here include "vfs" and those that
2685     ** correspond to flags that may be passed to the sqlite3_open_v2()
2686     ** method. */
2687     zOpt = &zFile[sqlite3Strlen30(zFile)+1];
2688     while( zOpt[0] ){
2689       int nOpt = sqlite3Strlen30(zOpt);
2690       char *zVal = &zOpt[nOpt+1];
2691       int nVal = sqlite3Strlen30(zVal);
2692 
2693       if( nOpt==3 && memcmp("vfs", zOpt, 3)==0 ){
2694         zVfs = zVal;
2695       }else{
2696         struct OpenMode {
2697           const char *z;
2698           int mode;
2699         } *aMode = 0;
2700         char *zModeType = 0;
2701         int mask = 0;
2702         int limit = 0;
2703 
2704         if( nOpt==5 && memcmp("cache", zOpt, 5)==0 ){
2705           static struct OpenMode aCacheMode[] = {
2706             { "shared",  SQLITE_OPEN_SHAREDCACHE },
2707             { "private", SQLITE_OPEN_PRIVATECACHE },
2708             { 0, 0 }
2709           };
2710 
2711           mask = SQLITE_OPEN_SHAREDCACHE|SQLITE_OPEN_PRIVATECACHE;
2712           aMode = aCacheMode;
2713           limit = mask;
2714           zModeType = "cache";
2715         }
2716         if( nOpt==4 && memcmp("mode", zOpt, 4)==0 ){
2717           static struct OpenMode aOpenMode[] = {
2718             { "ro",  SQLITE_OPEN_READONLY },
2719             { "rw",  SQLITE_OPEN_READWRITE },
2720             { "rwc", SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE },
2721             { "memory", SQLITE_OPEN_MEMORY },
2722             { 0, 0 }
2723           };
2724 
2725           mask = SQLITE_OPEN_READONLY | SQLITE_OPEN_READWRITE
2726                    | SQLITE_OPEN_CREATE | SQLITE_OPEN_MEMORY;
2727           aMode = aOpenMode;
2728           limit = mask & flags;
2729           zModeType = "access";
2730         }
2731 
2732         if( aMode ){
2733           int i;
2734           int mode = 0;
2735           for(i=0; aMode[i].z; i++){
2736             const char *z = aMode[i].z;
2737             if( nVal==sqlite3Strlen30(z) && 0==memcmp(zVal, z, nVal) ){
2738               mode = aMode[i].mode;
2739               break;
2740             }
2741           }
2742           if( mode==0 ){
2743             *pzErrMsg = sqlite3_mprintf("no such %s mode: %s", zModeType, zVal);
2744             rc = SQLITE_ERROR;
2745             goto parse_uri_out;
2746           }
2747           if( (mode & ~SQLITE_OPEN_MEMORY)>limit ){
2748             *pzErrMsg = sqlite3_mprintf("%s mode not allowed: %s",
2749                                         zModeType, zVal);
2750             rc = SQLITE_PERM;
2751             goto parse_uri_out;
2752           }
2753           flags = (flags & ~mask) | mode;
2754         }
2755       }
2756 
2757       zOpt = &zVal[nVal+1];
2758     }
2759 
2760   }else{
2761     zFile = sqlite3_malloc64(nUri+2);
2762     if( !zFile ) return SQLITE_NOMEM_BKPT;
2763     if( nUri ){
2764       memcpy(zFile, zUri, nUri);
2765     }
2766     zFile[nUri] = '\0';
2767     zFile[nUri+1] = '\0';
2768     flags &= ~SQLITE_OPEN_URI;
2769   }
2770 
2771   *ppVfs = sqlite3_vfs_find(zVfs);
2772   if( *ppVfs==0 ){
2773     *pzErrMsg = sqlite3_mprintf("no such vfs: %s", zVfs);
2774     rc = SQLITE_ERROR;
2775   }
2776  parse_uri_out:
2777   if( rc!=SQLITE_OK ){
2778     sqlite3_free(zFile);
2779     zFile = 0;
2780   }
2781   *pFlags = flags;
2782   *pzFile = zFile;
2783   return rc;
2784 }
2785 
2786 
2787 /*
2788 ** This routine does the work of opening a database on behalf of
2789 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
2790 ** is UTF-8 encoded.
2791 */
2792 static int openDatabase(
2793   const char *zFilename, /* Database filename UTF-8 encoded */
2794   sqlite3 **ppDb,        /* OUT: Returned database handle */
2795   unsigned int flags,    /* Operational flags */
2796   const char *zVfs       /* Name of the VFS to use */
2797 ){
2798   sqlite3 *db;                    /* Store allocated handle here */
2799   int rc;                         /* Return code */
2800   int isThreadsafe;               /* True for threadsafe connections */
2801   char *zOpen = 0;                /* Filename argument to pass to BtreeOpen() */
2802   char *zErrMsg = 0;              /* Error message from sqlite3ParseUri() */
2803 
2804 #ifdef SQLITE_ENABLE_API_ARMOR
2805   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
2806 #endif
2807   *ppDb = 0;
2808 #ifndef SQLITE_OMIT_AUTOINIT
2809   rc = sqlite3_initialize();
2810   if( rc ) return rc;
2811 #endif
2812 
2813   if( sqlite3GlobalConfig.bCoreMutex==0 ){
2814     isThreadsafe = 0;
2815   }else if( flags & SQLITE_OPEN_NOMUTEX ){
2816     isThreadsafe = 0;
2817   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
2818     isThreadsafe = 1;
2819   }else{
2820     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
2821   }
2822   if( flags & SQLITE_OPEN_PRIVATECACHE ){
2823     flags &= ~SQLITE_OPEN_SHAREDCACHE;
2824   }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
2825     flags |= SQLITE_OPEN_SHAREDCACHE;
2826   }
2827 
2828   /* Remove harmful bits from the flags parameter
2829   **
2830   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were
2831   ** dealt with in the previous code block.  Besides these, the only
2832   ** valid input flags for sqlite3_open_v2() are SQLITE_OPEN_READONLY,
2833   ** SQLITE_OPEN_READWRITE, SQLITE_OPEN_CREATE, SQLITE_OPEN_SHAREDCACHE,
2834   ** SQLITE_OPEN_PRIVATECACHE, and some reserved bits.  Silently mask
2835   ** off all other flags.
2836   */
2837   flags &=  ~( SQLITE_OPEN_DELETEONCLOSE |
2838                SQLITE_OPEN_EXCLUSIVE |
2839                SQLITE_OPEN_MAIN_DB |
2840                SQLITE_OPEN_TEMP_DB |
2841                SQLITE_OPEN_TRANSIENT_DB |
2842                SQLITE_OPEN_MAIN_JOURNAL |
2843                SQLITE_OPEN_TEMP_JOURNAL |
2844                SQLITE_OPEN_SUBJOURNAL |
2845                SQLITE_OPEN_MASTER_JOURNAL |
2846                SQLITE_OPEN_NOMUTEX |
2847                SQLITE_OPEN_FULLMUTEX |
2848                SQLITE_OPEN_WAL
2849              );
2850 
2851   /* Allocate the sqlite data structure */
2852   db = sqlite3MallocZero( sizeof(sqlite3) );
2853   if( db==0 ) goto opendb_out;
2854   if( isThreadsafe ){
2855     db->mutex = sqlite3MutexAlloc(SQLITE_MUTEX_RECURSIVE);
2856     if( db->mutex==0 ){
2857       sqlite3_free(db);
2858       db = 0;
2859       goto opendb_out;
2860     }
2861   }
2862   sqlite3_mutex_enter(db->mutex);
2863   db->errMask = 0xff;
2864   db->nDb = 2;
2865   db->magic = SQLITE_MAGIC_BUSY;
2866   db->aDb = db->aDbStatic;
2867 
2868   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
2869   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
2870   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;
2871   db->autoCommit = 1;
2872   db->nextAutovac = -1;
2873   db->szMmap = sqlite3GlobalConfig.szMmap;
2874   db->nextPagesize = 0;
2875   db->nMaxSorterMmap = 0x7FFFFFFF;
2876   db->flags |= SQLITE_ShortColNames | SQLITE_EnableTrigger | SQLITE_CacheSpill
2877 #if !defined(SQLITE_DEFAULT_AUTOMATIC_INDEX) || SQLITE_DEFAULT_AUTOMATIC_INDEX
2878                  | SQLITE_AutoIndex
2879 #endif
2880 #if SQLITE_DEFAULT_CKPTFULLFSYNC
2881                  | SQLITE_CkptFullFSync
2882 #endif
2883 #if SQLITE_DEFAULT_FILE_FORMAT<4
2884                  | SQLITE_LegacyFileFmt
2885 #endif
2886 #ifdef SQLITE_ENABLE_LOAD_EXTENSION
2887                  | SQLITE_LoadExtension
2888 #endif
2889 #if SQLITE_DEFAULT_RECURSIVE_TRIGGERS
2890                  | SQLITE_RecTriggers
2891 #endif
2892 #if defined(SQLITE_DEFAULT_FOREIGN_KEYS) && SQLITE_DEFAULT_FOREIGN_KEYS
2893                  | SQLITE_ForeignKeys
2894 #endif
2895 #if defined(SQLITE_REVERSE_UNORDERED_SELECTS)
2896                  | SQLITE_ReverseOrder
2897 #endif
2898 #if defined(SQLITE_ENABLE_OVERSIZE_CELL_CHECK)
2899                  | SQLITE_CellSizeCk
2900 #endif
2901 #if defined(SQLITE_ENABLE_FTS3_TOKENIZER)
2902                  | SQLITE_Fts3Tokenizer
2903 #endif
2904 #if defined(SQLITE_ENABLE_QPSG)
2905                  | SQLITE_EnableQPSG
2906 #endif
2907       ;
2908   sqlite3HashInit(&db->aCollSeq);
2909 #ifndef SQLITE_OMIT_VIRTUALTABLE
2910   sqlite3HashInit(&db->aModule);
2911 #endif
2912 
2913   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
2914   ** and UTF-16, so add a version for each to avoid any unnecessary
2915   ** conversions. The only error that can occur here is a malloc() failure.
2916   **
2917   ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
2918   ** functions:
2919   */
2920   createCollation(db, sqlite3StrBINARY, SQLITE_UTF8, 0, binCollFunc, 0);
2921   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16BE, 0, binCollFunc, 0);
2922   createCollation(db, sqlite3StrBINARY, SQLITE_UTF16LE, 0, binCollFunc, 0);
2923   createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
2924   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
2925   if( db->mallocFailed ){
2926     goto opendb_out;
2927   }
2928   /* EVIDENCE-OF: R-08308-17224 The default collating function for all
2929   ** strings is BINARY.
2930   */
2931   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, sqlite3StrBINARY, 0);
2932   assert( db->pDfltColl!=0 );
2933 
2934   /* Parse the filename/URI argument
2935   **
2936   ** Only allow sensible combinations of bits in the flags argument.
2937   ** Throw an error if any non-sense combination is used.  If we
2938   ** do not block illegal combinations here, it could trigger
2939   ** assert() statements in deeper layers.  Sensible combinations
2940   ** are:
2941   **
2942   **  1:  SQLITE_OPEN_READONLY
2943   **  2:  SQLITE_OPEN_READWRITE
2944   **  6:  SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE
2945   */
2946   db->openFlags = flags;
2947   assert( SQLITE_OPEN_READONLY  == 0x01 );
2948   assert( SQLITE_OPEN_READWRITE == 0x02 );
2949   assert( SQLITE_OPEN_CREATE    == 0x04 );
2950   testcase( (1<<(flags&7))==0x02 ); /* READONLY */
2951   testcase( (1<<(flags&7))==0x04 ); /* READWRITE */
2952   testcase( (1<<(flags&7))==0x40 ); /* READWRITE | CREATE */
2953   if( ((1<<(flags&7)) & 0x46)==0 ){
2954     rc = SQLITE_MISUSE_BKPT;  /* IMP: R-65497-44594 */
2955   }else{
2956     rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);
2957   }
2958   if( rc!=SQLITE_OK ){
2959     if( rc==SQLITE_NOMEM ) sqlite3OomFault(db);
2960     sqlite3ErrorWithMsg(db, rc, zErrMsg ? "%s" : 0, zErrMsg);
2961     sqlite3_free(zErrMsg);
2962     goto opendb_out;
2963   }
2964 
2965   /* Open the backend database driver */
2966   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
2967                         flags | SQLITE_OPEN_MAIN_DB);
2968   if( rc!=SQLITE_OK ){
2969     if( rc==SQLITE_IOERR_NOMEM ){
2970       rc = SQLITE_NOMEM_BKPT;
2971     }
2972     sqlite3Error(db, rc);
2973     goto opendb_out;
2974   }
2975   sqlite3BtreeEnter(db->aDb[0].pBt);
2976   db->aDb[0].pSchema = sqlite3SchemaGet(db, db->aDb[0].pBt);
2977   if( !db->mallocFailed ) ENC(db) = SCHEMA_ENC(db);
2978   sqlite3BtreeLeave(db->aDb[0].pBt);
2979   db->aDb[1].pSchema = sqlite3SchemaGet(db, 0);
2980 
2981   /* The default safety_level for the main database is FULL; for the temp
2982   ** database it is OFF. This matches the pager layer defaults.
2983   */
2984   db->aDb[0].zDbSName = "main";
2985   db->aDb[0].safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1;
2986   db->aDb[1].zDbSName = "temp";
2987   db->aDb[1].safety_level = PAGER_SYNCHRONOUS_OFF;
2988 
2989   db->magic = SQLITE_MAGIC_OPEN;
2990   if( db->mallocFailed ){
2991     goto opendb_out;
2992   }
2993 
2994   /* Register all built-in functions, but do not attempt to read the
2995   ** database schema yet. This is delayed until the first time the database
2996   ** is accessed.
2997   */
2998   sqlite3Error(db, SQLITE_OK);
2999   sqlite3RegisterPerConnectionBuiltinFunctions(db);
3000   rc = sqlite3_errcode(db);
3001 
3002 #ifdef SQLITE_ENABLE_FTS5
3003   /* Register any built-in FTS5 module before loading the automatic
3004   ** extensions. This allows automatic extensions to register FTS5
3005   ** tokenizers and auxiliary functions.  */
3006   if( !db->mallocFailed && rc==SQLITE_OK ){
3007     rc = sqlite3Fts5Init(db);
3008   }
3009 #endif
3010 
3011   /* Load automatic extensions - extensions that have been registered
3012   ** using the sqlite3_automatic_extension() API.
3013   */
3014   if( rc==SQLITE_OK ){
3015     sqlite3AutoLoadExtensions(db);
3016     rc = sqlite3_errcode(db);
3017     if( rc!=SQLITE_OK ){
3018       goto opendb_out;
3019     }
3020   }
3021 
3022 #ifdef SQLITE_ENABLE_FTS1
3023   if( !db->mallocFailed ){
3024     extern int sqlite3Fts1Init(sqlite3*);
3025     rc = sqlite3Fts1Init(db);
3026   }
3027 #endif
3028 
3029 #ifdef SQLITE_ENABLE_FTS2
3030   if( !db->mallocFailed && rc==SQLITE_OK ){
3031     extern int sqlite3Fts2Init(sqlite3*);
3032     rc = sqlite3Fts2Init(db);
3033   }
3034 #endif
3035 
3036 #ifdef SQLITE_ENABLE_FTS3 /* automatically defined by SQLITE_ENABLE_FTS4 */
3037   if( !db->mallocFailed && rc==SQLITE_OK ){
3038     rc = sqlite3Fts3Init(db);
3039   }
3040 #endif
3041 
3042 #ifdef SQLITE_ENABLE_ICU
3043   if( !db->mallocFailed && rc==SQLITE_OK ){
3044     rc = sqlite3IcuInit(db);
3045   }
3046 #endif
3047 
3048 #ifdef SQLITE_ENABLE_RTREE
3049   if( !db->mallocFailed && rc==SQLITE_OK){
3050     rc = sqlite3RtreeInit(db);
3051   }
3052 #endif
3053 
3054 #ifdef SQLITE_ENABLE_DBSTAT_VTAB
3055   if( !db->mallocFailed && rc==SQLITE_OK){
3056     rc = sqlite3DbstatRegister(db);
3057   }
3058 #endif
3059 
3060 #ifdef SQLITE_ENABLE_JSON1
3061   if( !db->mallocFailed && rc==SQLITE_OK){
3062     rc = sqlite3Json1Init(db);
3063   }
3064 #endif
3065 
3066 #ifdef SQLITE_ENABLE_STMTVTAB
3067   if( !db->mallocFailed && rc==SQLITE_OK){
3068     rc = sqlite3StmtVtabInit(db);
3069   }
3070 #endif
3071 
3072   /* -DSQLITE_DEFAULT_LOCKING_MODE=1 makes EXCLUSIVE the default locking
3073   ** mode.  -DSQLITE_DEFAULT_LOCKING_MODE=0 make NORMAL the default locking
3074   ** mode.  Doing nothing at all also makes NORMAL the default.
3075   */
3076 #ifdef SQLITE_DEFAULT_LOCKING_MODE
3077   db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
3078   sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
3079                           SQLITE_DEFAULT_LOCKING_MODE);
3080 #endif
3081 
3082   if( rc ) sqlite3Error(db, rc);
3083 
3084   /* Enable the lookaside-malloc subsystem */
3085   setupLookaside(db, 0, sqlite3GlobalConfig.szLookaside,
3086                         sqlite3GlobalConfig.nLookaside);
3087 
3088   sqlite3_wal_autocheckpoint(db, SQLITE_DEFAULT_WAL_AUTOCHECKPOINT);
3089 
3090 opendb_out:
3091   if( db ){
3092     assert( db->mutex!=0 || isThreadsafe==0
3093            || sqlite3GlobalConfig.bFullMutex==0 );
3094     sqlite3_mutex_leave(db->mutex);
3095   }
3096   rc = sqlite3_errcode(db);
3097   assert( db!=0 || rc==SQLITE_NOMEM );
3098   if( rc==SQLITE_NOMEM ){
3099     sqlite3_close(db);
3100     db = 0;
3101   }else if( rc!=SQLITE_OK ){
3102     db->magic = SQLITE_MAGIC_SICK;
3103   }
3104   *ppDb = db;
3105 #ifdef SQLITE_ENABLE_SQLLOG
3106   if( sqlite3GlobalConfig.xSqllog ){
3107     /* Opening a db handle. Fourth parameter is passed 0. */
3108     void *pArg = sqlite3GlobalConfig.pSqllogArg;
3109     sqlite3GlobalConfig.xSqllog(pArg, db, zFilename, 0);
3110   }
3111 #endif
3112 #if defined(SQLITE_HAS_CODEC)
3113   if( rc==SQLITE_OK ){
3114     const char *zKey;
3115     if( (zKey = sqlite3_uri_parameter(zOpen, "hexkey"))!=0 && zKey[0] ){
3116       u8 iByte;
3117       int i;
3118       char zDecoded[40];
3119       for(i=0, iByte=0; i<sizeof(zDecoded)*2 && sqlite3Isxdigit(zKey[i]); i++){
3120         iByte = (iByte<<4) + sqlite3HexToInt(zKey[i]);
3121         if( (i&1)!=0 ) zDecoded[i/2] = iByte;
3122       }
3123       sqlite3_key_v2(db, 0, zDecoded, i/2);
3124     }else if( (zKey = sqlite3_uri_parameter(zOpen, "key"))!=0 ){
3125       sqlite3_key_v2(db, 0, zKey, sqlite3Strlen30(zKey));
3126     }
3127   }
3128 #endif
3129   sqlite3_free(zOpen);
3130   return rc & 0xff;
3131 }
3132 
3133 /*
3134 ** Open a new database handle.
3135 */
3136 int sqlite3_open(
3137   const char *zFilename,
3138   sqlite3 **ppDb
3139 ){
3140   return openDatabase(zFilename, ppDb,
3141                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3142 }
3143 int sqlite3_open_v2(
3144   const char *filename,   /* Database filename (UTF-8) */
3145   sqlite3 **ppDb,         /* OUT: SQLite db handle */
3146   int flags,              /* Flags */
3147   const char *zVfs        /* Name of VFS module to use */
3148 ){
3149   return openDatabase(filename, ppDb, (unsigned int)flags, zVfs);
3150 }
3151 
3152 #ifndef SQLITE_OMIT_UTF16
3153 /*
3154 ** Open a new database handle.
3155 */
3156 int sqlite3_open16(
3157   const void *zFilename,
3158   sqlite3 **ppDb
3159 ){
3160   char const *zFilename8;   /* zFilename encoded in UTF-8 instead of UTF-16 */
3161   sqlite3_value *pVal;
3162   int rc;
3163 
3164 #ifdef SQLITE_ENABLE_API_ARMOR
3165   if( ppDb==0 ) return SQLITE_MISUSE_BKPT;
3166 #endif
3167   *ppDb = 0;
3168 #ifndef SQLITE_OMIT_AUTOINIT
3169   rc = sqlite3_initialize();
3170   if( rc ) return rc;
3171 #endif
3172   if( zFilename==0 ) zFilename = "\000\000";
3173   pVal = sqlite3ValueNew(0);
3174   sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
3175   zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
3176   if( zFilename8 ){
3177     rc = openDatabase(zFilename8, ppDb,
3178                       SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
3179     assert( *ppDb || rc==SQLITE_NOMEM );
3180     if( rc==SQLITE_OK && !DbHasProperty(*ppDb, 0, DB_SchemaLoaded) ){
3181       SCHEMA_ENC(*ppDb) = ENC(*ppDb) = SQLITE_UTF16NATIVE;
3182     }
3183   }else{
3184     rc = SQLITE_NOMEM_BKPT;
3185   }
3186   sqlite3ValueFree(pVal);
3187 
3188   return rc & 0xff;
3189 }
3190 #endif /* SQLITE_OMIT_UTF16 */
3191 
3192 /*
3193 ** Register a new collation sequence with the database handle db.
3194 */
3195 int sqlite3_create_collation(
3196   sqlite3* db,
3197   const char *zName,
3198   int enc,
3199   void* pCtx,
3200   int(*xCompare)(void*,int,const void*,int,const void*)
3201 ){
3202   return sqlite3_create_collation_v2(db, zName, enc, pCtx, xCompare, 0);
3203 }
3204 
3205 /*
3206 ** Register a new collation sequence with the database handle db.
3207 */
3208 int sqlite3_create_collation_v2(
3209   sqlite3* db,
3210   const char *zName,
3211   int enc,
3212   void* pCtx,
3213   int(*xCompare)(void*,int,const void*,int,const void*),
3214   void(*xDel)(void*)
3215 ){
3216   int rc;
3217 
3218 #ifdef SQLITE_ENABLE_API_ARMOR
3219   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3220 #endif
3221   sqlite3_mutex_enter(db->mutex);
3222   assert( !db->mallocFailed );
3223   rc = createCollation(db, zName, (u8)enc, pCtx, xCompare, xDel);
3224   rc = sqlite3ApiExit(db, rc);
3225   sqlite3_mutex_leave(db->mutex);
3226   return rc;
3227 }
3228 
3229 #ifndef SQLITE_OMIT_UTF16
3230 /*
3231 ** Register a new collation sequence with the database handle db.
3232 */
3233 int sqlite3_create_collation16(
3234   sqlite3* db,
3235   const void *zName,
3236   int enc,
3237   void* pCtx,
3238   int(*xCompare)(void*,int,const void*,int,const void*)
3239 ){
3240   int rc = SQLITE_OK;
3241   char *zName8;
3242 
3243 #ifdef SQLITE_ENABLE_API_ARMOR
3244   if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
3245 #endif
3246   sqlite3_mutex_enter(db->mutex);
3247   assert( !db->mallocFailed );
3248   zName8 = sqlite3Utf16to8(db, zName, -1, SQLITE_UTF16NATIVE);
3249   if( zName8 ){
3250     rc = createCollation(db, zName8, (u8)enc, pCtx, xCompare, 0);
3251     sqlite3DbFree(db, zName8);
3252   }
3253   rc = sqlite3ApiExit(db, rc);
3254   sqlite3_mutex_leave(db->mutex);
3255   return rc;
3256 }
3257 #endif /* SQLITE_OMIT_UTF16 */
3258 
3259 /*
3260 ** Register a collation sequence factory callback with the database handle
3261 ** db. Replace any previously installed collation sequence factory.
3262 */
3263 int sqlite3_collation_needed(
3264   sqlite3 *db,
3265   void *pCollNeededArg,
3266   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*)
3267 ){
3268 #ifdef SQLITE_ENABLE_API_ARMOR
3269   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3270 #endif
3271   sqlite3_mutex_enter(db->mutex);
3272   db->xCollNeeded = xCollNeeded;
3273   db->xCollNeeded16 = 0;
3274   db->pCollNeededArg = pCollNeededArg;
3275   sqlite3_mutex_leave(db->mutex);
3276   return SQLITE_OK;
3277 }
3278 
3279 #ifndef SQLITE_OMIT_UTF16
3280 /*
3281 ** Register a collation sequence factory callback with the database handle
3282 ** db. Replace any previously installed collation sequence factory.
3283 */
3284 int sqlite3_collation_needed16(
3285   sqlite3 *db,
3286   void *pCollNeededArg,
3287   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*)
3288 ){
3289 #ifdef SQLITE_ENABLE_API_ARMOR
3290   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3291 #endif
3292   sqlite3_mutex_enter(db->mutex);
3293   db->xCollNeeded = 0;
3294   db->xCollNeeded16 = xCollNeeded16;
3295   db->pCollNeededArg = pCollNeededArg;
3296   sqlite3_mutex_leave(db->mutex);
3297   return SQLITE_OK;
3298 }
3299 #endif /* SQLITE_OMIT_UTF16 */
3300 
3301 #ifndef SQLITE_OMIT_DEPRECATED
3302 /*
3303 ** This function is now an anachronism. It used to be used to recover from a
3304 ** malloc() failure, but SQLite now does this automatically.
3305 */
3306 int sqlite3_global_recover(void){
3307   return SQLITE_OK;
3308 }
3309 #endif
3310 
3311 /*
3312 ** Test to see whether or not the database connection is in autocommit
3313 ** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
3314 ** by default.  Autocommit is disabled by a BEGIN statement and reenabled
3315 ** by the next COMMIT or ROLLBACK.
3316 */
3317 int sqlite3_get_autocommit(sqlite3 *db){
3318 #ifdef SQLITE_ENABLE_API_ARMOR
3319   if( !sqlite3SafetyCheckOk(db) ){
3320     (void)SQLITE_MISUSE_BKPT;
3321     return 0;
3322   }
3323 #endif
3324   return db->autoCommit;
3325 }
3326 
3327 /*
3328 ** The following routines are substitutes for constants SQLITE_CORRUPT,
3329 ** SQLITE_MISUSE, SQLITE_CANTOPEN, SQLITE_NOMEM and possibly other error
3330 ** constants.  They serve two purposes:
3331 **
3332 **   1.  Serve as a convenient place to set a breakpoint in a debugger
3333 **       to detect when version error conditions occurs.
3334 **
3335 **   2.  Invoke sqlite3_log() to provide the source code location where
3336 **       a low-level error is first detected.
3337 */
3338 static int reportError(int iErr, int lineno, const char *zType){
3339   sqlite3_log(iErr, "%s at line %d of [%.10s]",
3340               zType, lineno, 20+sqlite3_sourceid());
3341   return iErr;
3342 }
3343 int sqlite3CorruptError(int lineno){
3344   testcase( sqlite3GlobalConfig.xLog!=0 );
3345   return reportError(SQLITE_CORRUPT, lineno, "database corruption");
3346 }
3347 int sqlite3MisuseError(int lineno){
3348   testcase( sqlite3GlobalConfig.xLog!=0 );
3349   return reportError(SQLITE_MISUSE, lineno, "misuse");
3350 }
3351 int sqlite3CantopenError(int lineno){
3352   testcase( sqlite3GlobalConfig.xLog!=0 );
3353   return reportError(SQLITE_CANTOPEN, lineno, "cannot open file");
3354 }
3355 #ifdef SQLITE_DEBUG
3356 int sqlite3CorruptPgnoError(int lineno, Pgno pgno){
3357   char zMsg[100];
3358   sqlite3_snprintf(sizeof(zMsg), zMsg, "database corruption page %d", pgno);
3359   testcase( sqlite3GlobalConfig.xLog!=0 );
3360   return reportError(SQLITE_CORRUPT, lineno, zMsg);
3361 }
3362 int sqlite3NomemError(int lineno){
3363   testcase( sqlite3GlobalConfig.xLog!=0 );
3364   return reportError(SQLITE_NOMEM, lineno, "OOM");
3365 }
3366 int sqlite3IoerrnomemError(int lineno){
3367   testcase( sqlite3GlobalConfig.xLog!=0 );
3368   return reportError(SQLITE_IOERR_NOMEM, lineno, "I/O OOM error");
3369 }
3370 #endif
3371 
3372 #ifndef SQLITE_OMIT_DEPRECATED
3373 /*
3374 ** This is a convenience routine that makes sure that all thread-specific
3375 ** data for this thread has been deallocated.
3376 **
3377 ** SQLite no longer uses thread-specific data so this routine is now a
3378 ** no-op.  It is retained for historical compatibility.
3379 */
3380 void sqlite3_thread_cleanup(void){
3381 }
3382 #endif
3383 
3384 /*
3385 ** Return meta information about a specific column of a database table.
3386 ** See comment in sqlite3.h (sqlite.h.in) for details.
3387 */
3388 int sqlite3_table_column_metadata(
3389   sqlite3 *db,                /* Connection handle */
3390   const char *zDbName,        /* Database name or NULL */
3391   const char *zTableName,     /* Table name */
3392   const char *zColumnName,    /* Column name */
3393   char const **pzDataType,    /* OUTPUT: Declared data type */
3394   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
3395   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
3396   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
3397   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
3398 ){
3399   int rc;
3400   char *zErrMsg = 0;
3401   Table *pTab = 0;
3402   Column *pCol = 0;
3403   int iCol = 0;
3404   char const *zDataType = 0;
3405   char const *zCollSeq = 0;
3406   int notnull = 0;
3407   int primarykey = 0;
3408   int autoinc = 0;
3409 
3410 
3411 #ifdef SQLITE_ENABLE_API_ARMOR
3412   if( !sqlite3SafetyCheckOk(db) || zTableName==0 ){
3413     return SQLITE_MISUSE_BKPT;
3414   }
3415 #endif
3416 
3417   /* Ensure the database schema has been loaded */
3418   sqlite3_mutex_enter(db->mutex);
3419   sqlite3BtreeEnterAll(db);
3420   rc = sqlite3Init(db, &zErrMsg);
3421   if( SQLITE_OK!=rc ){
3422     goto error_out;
3423   }
3424 
3425   /* Locate the table in question */
3426   pTab = sqlite3FindTable(db, zTableName, zDbName);
3427   if( !pTab || pTab->pSelect ){
3428     pTab = 0;
3429     goto error_out;
3430   }
3431 
3432   /* Find the column for which info is requested */
3433   if( zColumnName==0 ){
3434     /* Query for existance of table only */
3435   }else{
3436     for(iCol=0; iCol<pTab->nCol; iCol++){
3437       pCol = &pTab->aCol[iCol];
3438       if( 0==sqlite3StrICmp(pCol->zName, zColumnName) ){
3439         break;
3440       }
3441     }
3442     if( iCol==pTab->nCol ){
3443       if( HasRowid(pTab) && sqlite3IsRowid(zColumnName) ){
3444         iCol = pTab->iPKey;
3445         pCol = iCol>=0 ? &pTab->aCol[iCol] : 0;
3446       }else{
3447         pTab = 0;
3448         goto error_out;
3449       }
3450     }
3451   }
3452 
3453   /* The following block stores the meta information that will be returned
3454   ** to the caller in local variables zDataType, zCollSeq, notnull, primarykey
3455   ** and autoinc. At this point there are two possibilities:
3456   **
3457   **     1. The specified column name was rowid", "oid" or "_rowid_"
3458   **        and there is no explicitly declared IPK column.
3459   **
3460   **     2. The table is not a view and the column name identified an
3461   **        explicitly declared column. Copy meta information from *pCol.
3462   */
3463   if( pCol ){
3464     zDataType = sqlite3ColumnType(pCol,0);
3465     zCollSeq = pCol->zColl;
3466     notnull = pCol->notNull!=0;
3467     primarykey  = (pCol->colFlags & COLFLAG_PRIMKEY)!=0;
3468     autoinc = pTab->iPKey==iCol && (pTab->tabFlags & TF_Autoincrement)!=0;
3469   }else{
3470     zDataType = "INTEGER";
3471     primarykey = 1;
3472   }
3473   if( !zCollSeq ){
3474     zCollSeq = sqlite3StrBINARY;
3475   }
3476 
3477 error_out:
3478   sqlite3BtreeLeaveAll(db);
3479 
3480   /* Whether the function call succeeded or failed, set the output parameters
3481   ** to whatever their local counterparts contain. If an error did occur,
3482   ** this has the effect of zeroing all output parameters.
3483   */
3484   if( pzDataType ) *pzDataType = zDataType;
3485   if( pzCollSeq ) *pzCollSeq = zCollSeq;
3486   if( pNotNull ) *pNotNull = notnull;
3487   if( pPrimaryKey ) *pPrimaryKey = primarykey;
3488   if( pAutoinc ) *pAutoinc = autoinc;
3489 
3490   if( SQLITE_OK==rc && !pTab ){
3491     sqlite3DbFree(db, zErrMsg);
3492     zErrMsg = sqlite3MPrintf(db, "no such table column: %s.%s", zTableName,
3493         zColumnName);
3494     rc = SQLITE_ERROR;
3495   }
3496   sqlite3ErrorWithMsg(db, rc, (zErrMsg?"%s":0), zErrMsg);
3497   sqlite3DbFree(db, zErrMsg);
3498   rc = sqlite3ApiExit(db, rc);
3499   sqlite3_mutex_leave(db->mutex);
3500   return rc;
3501 }
3502 
3503 /*
3504 ** Sleep for a little while.  Return the amount of time slept.
3505 */
3506 int sqlite3_sleep(int ms){
3507   sqlite3_vfs *pVfs;
3508   int rc;
3509   pVfs = sqlite3_vfs_find(0);
3510   if( pVfs==0 ) return 0;
3511 
3512   /* This function works in milliseconds, but the underlying OsSleep()
3513   ** API uses microseconds. Hence the 1000's.
3514   */
3515   rc = (sqlite3OsSleep(pVfs, 1000*ms)/1000);
3516   return rc;
3517 }
3518 
3519 /*
3520 ** Enable or disable the extended result codes.
3521 */
3522 int sqlite3_extended_result_codes(sqlite3 *db, int onoff){
3523 #ifdef SQLITE_ENABLE_API_ARMOR
3524   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3525 #endif
3526   sqlite3_mutex_enter(db->mutex);
3527   db->errMask = onoff ? 0xffffffff : 0xff;
3528   sqlite3_mutex_leave(db->mutex);
3529   return SQLITE_OK;
3530 }
3531 
3532 /*
3533 ** Invoke the xFileControl method on a particular database.
3534 */
3535 int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
3536   int rc = SQLITE_ERROR;
3537   Btree *pBtree;
3538 
3539 #ifdef SQLITE_ENABLE_API_ARMOR
3540   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
3541 #endif
3542   sqlite3_mutex_enter(db->mutex);
3543   pBtree = sqlite3DbNameToBtree(db, zDbName);
3544   if( pBtree ){
3545     Pager *pPager;
3546     sqlite3_file *fd;
3547     sqlite3BtreeEnter(pBtree);
3548     pPager = sqlite3BtreePager(pBtree);
3549     assert( pPager!=0 );
3550     fd = sqlite3PagerFile(pPager);
3551     assert( fd!=0 );
3552     if( op==SQLITE_FCNTL_FILE_POINTER ){
3553       *(sqlite3_file**)pArg = fd;
3554       rc = SQLITE_OK;
3555     }else if( op==SQLITE_FCNTL_VFS_POINTER ){
3556       *(sqlite3_vfs**)pArg = sqlite3PagerVfs(pPager);
3557       rc = SQLITE_OK;
3558     }else if( op==SQLITE_FCNTL_JOURNAL_POINTER ){
3559       *(sqlite3_file**)pArg = sqlite3PagerJrnlFile(pPager);
3560       rc = SQLITE_OK;
3561     }else if( fd->pMethods ){
3562       rc = sqlite3OsFileControl(fd, op, pArg);
3563     }else{
3564       rc = SQLITE_NOTFOUND;
3565     }
3566     sqlite3BtreeLeave(pBtree);
3567   }
3568   sqlite3_mutex_leave(db->mutex);
3569   return rc;
3570 }
3571 
3572 /*
3573 ** Interface to the testing logic.
3574 */
3575 int sqlite3_test_control(int op, ...){
3576   int rc = 0;
3577 #ifdef SQLITE_UNTESTABLE
3578   UNUSED_PARAMETER(op);
3579 #else
3580   va_list ap;
3581   va_start(ap, op);
3582   switch( op ){
3583 
3584     /*
3585     ** Save the current state of the PRNG.
3586     */
3587     case SQLITE_TESTCTRL_PRNG_SAVE: {
3588       sqlite3PrngSaveState();
3589       break;
3590     }
3591 
3592     /*
3593     ** Restore the state of the PRNG to the last state saved using
3594     ** PRNG_SAVE.  If PRNG_SAVE has never before been called, then
3595     ** this verb acts like PRNG_RESET.
3596     */
3597     case SQLITE_TESTCTRL_PRNG_RESTORE: {
3598       sqlite3PrngRestoreState();
3599       break;
3600     }
3601 
3602     /*
3603     ** Reset the PRNG back to its uninitialized state.  The next call
3604     ** to sqlite3_randomness() will reseed the PRNG using a single call
3605     ** to the xRandomness method of the default VFS.
3606     */
3607     case SQLITE_TESTCTRL_PRNG_RESET: {
3608       sqlite3_randomness(0,0);
3609       break;
3610     }
3611 
3612     /*
3613     **  sqlite3_test_control(BITVEC_TEST, size, program)
3614     **
3615     ** Run a test against a Bitvec object of size.  The program argument
3616     ** is an array of integers that defines the test.  Return -1 on a
3617     ** memory allocation error, 0 on success, or non-zero for an error.
3618     ** See the sqlite3BitvecBuiltinTest() for additional information.
3619     */
3620     case SQLITE_TESTCTRL_BITVEC_TEST: {
3621       int sz = va_arg(ap, int);
3622       int *aProg = va_arg(ap, int*);
3623       rc = sqlite3BitvecBuiltinTest(sz, aProg);
3624       break;
3625     }
3626 
3627     /*
3628     **  sqlite3_test_control(FAULT_INSTALL, xCallback)
3629     **
3630     ** Arrange to invoke xCallback() whenever sqlite3FaultSim() is called,
3631     ** if xCallback is not NULL.
3632     **
3633     ** As a test of the fault simulator mechanism itself, sqlite3FaultSim(0)
3634     ** is called immediately after installing the new callback and the return
3635     ** value from sqlite3FaultSim(0) becomes the return from
3636     ** sqlite3_test_control().
3637     */
3638     case SQLITE_TESTCTRL_FAULT_INSTALL: {
3639       /* MSVC is picky about pulling func ptrs from va lists.
3640       ** http://support.microsoft.com/kb/47961
3641       ** sqlite3GlobalConfig.xTestCallback = va_arg(ap, int(*)(int));
3642       */
3643       typedef int(*TESTCALLBACKFUNC_t)(int);
3644       sqlite3GlobalConfig.xTestCallback = va_arg(ap, TESTCALLBACKFUNC_t);
3645       rc = sqlite3FaultSim(0);
3646       break;
3647     }
3648 
3649     /*
3650     **  sqlite3_test_control(BENIGN_MALLOC_HOOKS, xBegin, xEnd)
3651     **
3652     ** Register hooks to call to indicate which malloc() failures
3653     ** are benign.
3654     */
3655     case SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS: {
3656       typedef void (*void_function)(void);
3657       void_function xBenignBegin;
3658       void_function xBenignEnd;
3659       xBenignBegin = va_arg(ap, void_function);
3660       xBenignEnd = va_arg(ap, void_function);
3661       sqlite3BenignMallocHooks(xBenignBegin, xBenignEnd);
3662       break;
3663     }
3664 
3665     /*
3666     **  sqlite3_test_control(SQLITE_TESTCTRL_PENDING_BYTE, unsigned int X)
3667     **
3668     ** Set the PENDING byte to the value in the argument, if X>0.
3669     ** Make no changes if X==0.  Return the value of the pending byte
3670     ** as it existing before this routine was called.
3671     **
3672     ** IMPORTANT:  Changing the PENDING byte from 0x40000000 results in
3673     ** an incompatible database file format.  Changing the PENDING byte
3674     ** while any database connection is open results in undefined and
3675     ** deleterious behavior.
3676     */
3677     case SQLITE_TESTCTRL_PENDING_BYTE: {
3678       rc = PENDING_BYTE;
3679 #ifndef SQLITE_OMIT_WSD
3680       {
3681         unsigned int newVal = va_arg(ap, unsigned int);
3682         if( newVal ) sqlite3PendingByte = newVal;
3683       }
3684 #endif
3685       break;
3686     }
3687 
3688     /*
3689     **  sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, int X)
3690     **
3691     ** This action provides a run-time test to see whether or not
3692     ** assert() was enabled at compile-time.  If X is true and assert()
3693     ** is enabled, then the return value is true.  If X is true and
3694     ** assert() is disabled, then the return value is zero.  If X is
3695     ** false and assert() is enabled, then the assertion fires and the
3696     ** process aborts.  If X is false and assert() is disabled, then the
3697     ** return value is zero.
3698     */
3699     case SQLITE_TESTCTRL_ASSERT: {
3700       volatile int x = 0;
3701       assert( /*side-effects-ok*/ (x = va_arg(ap,int))!=0 );
3702       rc = x;
3703       break;
3704     }
3705 
3706 
3707     /*
3708     **  sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, int X)
3709     **
3710     ** This action provides a run-time test to see how the ALWAYS and
3711     ** NEVER macros were defined at compile-time.
3712     **
3713     ** The return value is ALWAYS(X).
3714     **
3715     ** The recommended test is X==2.  If the return value is 2, that means
3716     ** ALWAYS() and NEVER() are both no-op pass-through macros, which is the
3717     ** default setting.  If the return value is 1, then ALWAYS() is either
3718     ** hard-coded to true or else it asserts if its argument is false.
3719     ** The first behavior (hard-coded to true) is the case if
3720     ** SQLITE_TESTCTRL_ASSERT shows that assert() is disabled and the second
3721     ** behavior (assert if the argument to ALWAYS() is false) is the case if
3722     ** SQLITE_TESTCTRL_ASSERT shows that assert() is enabled.
3723     **
3724     ** The run-time test procedure might look something like this:
3725     **
3726     **    if( sqlite3_test_control(SQLITE_TESTCTRL_ALWAYS, 2)==2 ){
3727     **      // ALWAYS() and NEVER() are no-op pass-through macros
3728     **    }else if( sqlite3_test_control(SQLITE_TESTCTRL_ASSERT, 1) ){
3729     **      // ALWAYS(x) asserts that x is true. NEVER(x) asserts x is false.
3730     **    }else{
3731     **      // ALWAYS(x) is a constant 1.  NEVER(x) is a constant 0.
3732     **    }
3733     */
3734     case SQLITE_TESTCTRL_ALWAYS: {
3735       int x = va_arg(ap,int);
3736       rc = ALWAYS(x);
3737       break;
3738     }
3739 
3740     /*
3741     **   sqlite3_test_control(SQLITE_TESTCTRL_BYTEORDER);
3742     **
3743     ** The integer returned reveals the byte-order of the computer on which
3744     ** SQLite is running:
3745     **
3746     **       1     big-endian,    determined at run-time
3747     **      10     little-endian, determined at run-time
3748     **  432101     big-endian,    determined at compile-time
3749     **  123410     little-endian, determined at compile-time
3750     */
3751     case SQLITE_TESTCTRL_BYTEORDER: {
3752       rc = SQLITE_BYTEORDER*100 + SQLITE_LITTLEENDIAN*10 + SQLITE_BIGENDIAN;
3753       break;
3754     }
3755 
3756     /*   sqlite3_test_control(SQLITE_TESTCTRL_RESERVE, sqlite3 *db, int N)
3757     **
3758     ** Set the nReserve size to N for the main database on the database
3759     ** connection db.
3760     */
3761     case SQLITE_TESTCTRL_RESERVE: {
3762       sqlite3 *db = va_arg(ap, sqlite3*);
3763       int x = va_arg(ap,int);
3764       sqlite3_mutex_enter(db->mutex);
3765       sqlite3BtreeSetPageSize(db->aDb[0].pBt, 0, x, 0);
3766       sqlite3_mutex_leave(db->mutex);
3767       break;
3768     }
3769 
3770     /*  sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS, sqlite3 *db, int N)
3771     **
3772     ** Enable or disable various optimizations for testing purposes.  The
3773     ** argument N is a bitmask of optimizations to be disabled.  For normal
3774     ** operation N should be 0.  The idea is that a test program (like the
3775     ** SQL Logic Test or SLT test module) can run the same SQL multiple times
3776     ** with various optimizations disabled to verify that the same answer
3777     ** is obtained in every case.
3778     */
3779     case SQLITE_TESTCTRL_OPTIMIZATIONS: {
3780       sqlite3 *db = va_arg(ap, sqlite3*);
3781       db->dbOptFlags = (u16)(va_arg(ap, int) & 0xffff);
3782       break;
3783     }
3784 
3785 #ifdef SQLITE_N_KEYWORD
3786     /* sqlite3_test_control(SQLITE_TESTCTRL_ISKEYWORD, const char *zWord)
3787     **
3788     ** If zWord is a keyword recognized by the parser, then return the
3789     ** number of keywords.  Or if zWord is not a keyword, return 0.
3790     **
3791     ** This test feature is only available in the amalgamation since
3792     ** the SQLITE_N_KEYWORD macro is not defined in this file if SQLite
3793     ** is built using separate source files.
3794     */
3795     case SQLITE_TESTCTRL_ISKEYWORD: {
3796       const char *zWord = va_arg(ap, const char*);
3797       int n = sqlite3Strlen30(zWord);
3798       rc = (sqlite3KeywordCode((u8*)zWord, n)!=TK_ID) ? SQLITE_N_KEYWORD : 0;
3799       break;
3800     }
3801 #endif
3802 
3803     /* sqlite3_test_control(SQLITE_TESTCTRL_SCRATCHMALLOC, sz, &pNew, pFree);
3804     **
3805     ** Pass pFree into sqlite3ScratchFree().
3806     ** If sz>0 then allocate a scratch buffer into pNew.
3807     */
3808     case SQLITE_TESTCTRL_SCRATCHMALLOC: {
3809       void *pFree, **ppNew;
3810       int sz;
3811       sz = va_arg(ap, int);
3812       ppNew = va_arg(ap, void**);
3813       pFree = va_arg(ap, void*);
3814       if( sz ) *ppNew = sqlite3ScratchMalloc(sz);
3815       sqlite3ScratchFree(pFree);
3816       break;
3817     }
3818 
3819     /*   sqlite3_test_control(SQLITE_TESTCTRL_LOCALTIME_FAULT, int onoff);
3820     **
3821     ** If parameter onoff is non-zero, configure the wrappers so that all
3822     ** subsequent calls to localtime() and variants fail. If onoff is zero,
3823     ** undo this setting.
3824     */
3825     case SQLITE_TESTCTRL_LOCALTIME_FAULT: {
3826       sqlite3GlobalConfig.bLocaltimeFault = va_arg(ap, int);
3827       break;
3828     }
3829 
3830     /*   sqlite3_test_control(SQLITE_TESTCTRL_NEVER_CORRUPT, int);
3831     **
3832     ** Set or clear a flag that indicates that the database file is always well-
3833     ** formed and never corrupt.  This flag is clear by default, indicating that
3834     ** database files might have arbitrary corruption.  Setting the flag during
3835     ** testing causes certain assert() statements in the code to be activated
3836     ** that demonstrat invariants on well-formed database files.
3837     */
3838     case SQLITE_TESTCTRL_NEVER_CORRUPT: {
3839       sqlite3GlobalConfig.neverCorrupt = va_arg(ap, int);
3840       break;
3841     }
3842 
3843     /* Set the threshold at which OP_Once counters reset back to zero.
3844     ** By default this is 0x7ffffffe (over 2 billion), but that value is
3845     ** too big to test in a reasonable amount of time, so this control is
3846     ** provided to set a small and easily reachable reset value.
3847     */
3848     case SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD: {
3849       sqlite3GlobalConfig.iOnceResetThreshold = va_arg(ap, int);
3850       break;
3851     }
3852 
3853     /*   sqlite3_test_control(SQLITE_TESTCTRL_VDBE_COVERAGE, xCallback, ptr);
3854     **
3855     ** Set the VDBE coverage callback function to xCallback with context
3856     ** pointer ptr.
3857     */
3858     case SQLITE_TESTCTRL_VDBE_COVERAGE: {
3859 #ifdef SQLITE_VDBE_COVERAGE
3860       typedef void (*branch_callback)(void*,int,u8,u8);
3861       sqlite3GlobalConfig.xVdbeBranch = va_arg(ap,branch_callback);
3862       sqlite3GlobalConfig.pVdbeBranchArg = va_arg(ap,void*);
3863 #endif
3864       break;
3865     }
3866 
3867     /*   sqlite3_test_control(SQLITE_TESTCTRL_SORTER_MMAP, db, nMax); */
3868     case SQLITE_TESTCTRL_SORTER_MMAP: {
3869       sqlite3 *db = va_arg(ap, sqlite3*);
3870       db->nMaxSorterMmap = va_arg(ap, int);
3871       break;
3872     }
3873 
3874     /*   sqlite3_test_control(SQLITE_TESTCTRL_ISINIT);
3875     **
3876     ** Return SQLITE_OK if SQLite has been initialized and SQLITE_ERROR if
3877     ** not.
3878     */
3879     case SQLITE_TESTCTRL_ISINIT: {
3880       if( sqlite3GlobalConfig.isInit==0 ) rc = SQLITE_ERROR;
3881       break;
3882     }
3883 
3884     /*  sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, db, dbName, onOff, tnum);
3885     **
3886     ** This test control is used to create imposter tables.  "db" is a pointer
3887     ** to the database connection.  dbName is the database name (ex: "main" or
3888     ** "temp") which will receive the imposter.  "onOff" turns imposter mode on
3889     ** or off.  "tnum" is the root page of the b-tree to which the imposter
3890     ** table should connect.
3891     **
3892     ** Enable imposter mode only when the schema has already been parsed.  Then
3893     ** run a single CREATE TABLE statement to construct the imposter table in
3894     ** the parsed schema.  Then turn imposter mode back off again.
3895     **
3896     ** If onOff==0 and tnum>0 then reset the schema for all databases, causing
3897     ** the schema to be reparsed the next time it is needed.  This has the
3898     ** effect of erasing all imposter tables.
3899     */
3900     case SQLITE_TESTCTRL_IMPOSTER: {
3901       sqlite3 *db = va_arg(ap, sqlite3*);
3902       sqlite3_mutex_enter(db->mutex);
3903       db->init.iDb = sqlite3FindDbName(db, va_arg(ap,const char*));
3904       db->init.busy = db->init.imposterTable = va_arg(ap,int);
3905       db->init.newTnum = va_arg(ap,int);
3906       if( db->init.busy==0 && db->init.newTnum>0 ){
3907         sqlite3ResetAllSchemasOfConnection(db);
3908       }
3909       sqlite3_mutex_leave(db->mutex);
3910       break;
3911     }
3912   }
3913   va_end(ap);
3914 #endif /* SQLITE_UNTESTABLE */
3915   return rc;
3916 }
3917 
3918 /*
3919 ** This is a utility routine, useful to VFS implementations, that checks
3920 ** to see if a database file was a URI that contained a specific query
3921 ** parameter, and if so obtains the value of the query parameter.
3922 **
3923 ** The zFilename argument is the filename pointer passed into the xOpen()
3924 ** method of a VFS implementation.  The zParam argument is the name of the
3925 ** query parameter we seek.  This routine returns the value of the zParam
3926 ** parameter if it exists.  If the parameter does not exist, this routine
3927 ** returns a NULL pointer.
3928 */
3929 const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam){
3930   if( zFilename==0 || zParam==0 ) return 0;
3931   zFilename += sqlite3Strlen30(zFilename) + 1;
3932   while( zFilename[0] ){
3933     int x = strcmp(zFilename, zParam);
3934     zFilename += sqlite3Strlen30(zFilename) + 1;
3935     if( x==0 ) return zFilename;
3936     zFilename += sqlite3Strlen30(zFilename) + 1;
3937   }
3938   return 0;
3939 }
3940 
3941 /*
3942 ** Return a boolean value for a query parameter.
3943 */
3944 int sqlite3_uri_boolean(const char *zFilename, const char *zParam, int bDflt){
3945   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3946   bDflt = bDflt!=0;
3947   return z ? sqlite3GetBoolean(z, bDflt) : bDflt;
3948 }
3949 
3950 /*
3951 ** Return a 64-bit integer value for a query parameter.
3952 */
3953 sqlite3_int64 sqlite3_uri_int64(
3954   const char *zFilename,    /* Filename as passed to xOpen */
3955   const char *zParam,       /* URI parameter sought */
3956   sqlite3_int64 bDflt       /* return if parameter is missing */
3957 ){
3958   const char *z = sqlite3_uri_parameter(zFilename, zParam);
3959   sqlite3_int64 v;
3960   if( z && sqlite3DecOrHexToI64(z, &v)==SQLITE_OK ){
3961     bDflt = v;
3962   }
3963   return bDflt;
3964 }
3965 
3966 /*
3967 ** Return the Btree pointer identified by zDbName.  Return NULL if not found.
3968 */
3969 Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
3970   int iDb = zDbName ? sqlite3FindDbName(db, zDbName) : 0;
3971   return iDb<0 ? 0 : db->aDb[iDb].pBt;
3972 }
3973 
3974 /*
3975 ** Return the filename of the database associated with a database
3976 ** connection.
3977 */
3978 const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
3979   Btree *pBt;
3980 #ifdef SQLITE_ENABLE_API_ARMOR
3981   if( !sqlite3SafetyCheckOk(db) ){
3982     (void)SQLITE_MISUSE_BKPT;
3983     return 0;
3984   }
3985 #endif
3986   pBt = sqlite3DbNameToBtree(db, zDbName);
3987   return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
3988 }
3989 
3990 /*
3991 ** Return 1 if database is read-only or 0 if read/write.  Return -1 if
3992 ** no such database exists.
3993 */
3994 int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
3995   Btree *pBt;
3996 #ifdef SQLITE_ENABLE_API_ARMOR
3997   if( !sqlite3SafetyCheckOk(db) ){
3998     (void)SQLITE_MISUSE_BKPT;
3999     return -1;
4000   }
4001 #endif
4002   pBt = sqlite3DbNameToBtree(db, zDbName);
4003   return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
4004 }
4005 
4006 #ifdef SQLITE_ENABLE_SNAPSHOT
4007 /*
4008 ** Obtain a snapshot handle for the snapshot of database zDb currently
4009 ** being read by handle db.
4010 */
4011 int sqlite3_snapshot_get(
4012   sqlite3 *db,
4013   const char *zDb,
4014   sqlite3_snapshot **ppSnapshot
4015 ){
4016   int rc = SQLITE_ERROR;
4017 #ifndef SQLITE_OMIT_WAL
4018 
4019 #ifdef SQLITE_ENABLE_API_ARMOR
4020   if( !sqlite3SafetyCheckOk(db) ){
4021     return SQLITE_MISUSE_BKPT;
4022   }
4023 #endif
4024   sqlite3_mutex_enter(db->mutex);
4025 
4026   if( db->autoCommit==0 ){
4027     int iDb = sqlite3FindDbName(db, zDb);
4028     if( iDb==0 || iDb>1 ){
4029       Btree *pBt = db->aDb[iDb].pBt;
4030       if( 0==sqlite3BtreeIsInTrans(pBt) ){
4031         rc = sqlite3BtreeBeginTrans(pBt, 0);
4032         if( rc==SQLITE_OK ){
4033           rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
4034         }
4035       }
4036     }
4037   }
4038 
4039   sqlite3_mutex_leave(db->mutex);
4040 #endif   /* SQLITE_OMIT_WAL */
4041   return rc;
4042 }
4043 
4044 /*
4045 ** Open a read-transaction on the snapshot idendified by pSnapshot.
4046 */
4047 int sqlite3_snapshot_open(
4048   sqlite3 *db,
4049   const char *zDb,
4050   sqlite3_snapshot *pSnapshot
4051 ){
4052   int rc = SQLITE_ERROR;
4053 #ifndef SQLITE_OMIT_WAL
4054 
4055 #ifdef SQLITE_ENABLE_API_ARMOR
4056   if( !sqlite3SafetyCheckOk(db) ){
4057     return SQLITE_MISUSE_BKPT;
4058   }
4059 #endif
4060   sqlite3_mutex_enter(db->mutex);
4061   if( db->autoCommit==0 ){
4062     int iDb;
4063     iDb = sqlite3FindDbName(db, zDb);
4064     if( iDb==0 || iDb>1 ){
4065       Btree *pBt = db->aDb[iDb].pBt;
4066       if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4067         rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
4068         if( rc==SQLITE_OK ){
4069           rc = sqlite3BtreeBeginTrans(pBt, 0);
4070           sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
4071         }
4072       }
4073     }
4074   }
4075 
4076   sqlite3_mutex_leave(db->mutex);
4077 #endif   /* SQLITE_OMIT_WAL */
4078   return rc;
4079 }
4080 
4081 /*
4082 ** Recover as many snapshots as possible from the wal file associated with
4083 ** schema zDb of database db.
4084 */
4085 int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb){
4086   int rc = SQLITE_ERROR;
4087   int iDb;
4088 #ifndef SQLITE_OMIT_WAL
4089 
4090 #ifdef SQLITE_ENABLE_API_ARMOR
4091   if( !sqlite3SafetyCheckOk(db) ){
4092     return SQLITE_MISUSE_BKPT;
4093   }
4094 #endif
4095 
4096   sqlite3_mutex_enter(db->mutex);
4097   iDb = sqlite3FindDbName(db, zDb);
4098   if( iDb==0 || iDb>1 ){
4099     Btree *pBt = db->aDb[iDb].pBt;
4100     if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
4101       rc = sqlite3BtreeBeginTrans(pBt, 0);
4102       if( rc==SQLITE_OK ){
4103         rc = sqlite3PagerSnapshotRecover(sqlite3BtreePager(pBt));
4104         sqlite3BtreeCommit(pBt);
4105       }
4106     }
4107   }
4108   sqlite3_mutex_leave(db->mutex);
4109 #endif   /* SQLITE_OMIT_WAL */
4110   return rc;
4111 }
4112 
4113 /*
4114 ** Free a snapshot handle obtained from sqlite3_snapshot_get().
4115 */
4116 void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
4117   sqlite3_free(pSnapshot);
4118 }
4119 #endif /* SQLITE_ENABLE_SNAPSHOT */
4120 
4121 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
4122 /*
4123 ** Given the name of a compile-time option, return true if that option
4124 ** was used and false if not.
4125 **
4126 ** The name can optionally begin with "SQLITE_" but the "SQLITE_" prefix
4127 ** is not required for a match.
4128 */
4129 int sqlite3_compileoption_used(const char *zOptName){
4130   int i, n;
4131   int nOpt;
4132   const char **azCompileOpt;
4133 
4134 #if SQLITE_ENABLE_API_ARMOR
4135   if( zOptName==0 ){
4136     (void)SQLITE_MISUSE_BKPT;
4137     return 0;
4138   }
4139 #endif
4140 
4141   azCompileOpt = sqlite3CompileOptions(&nOpt);
4142 
4143   if( sqlite3StrNICmp(zOptName, "SQLITE_", 7)==0 ) zOptName += 7;
4144   n = sqlite3Strlen30(zOptName);
4145 
4146   /* Since nOpt is normally in single digits, a linear search is
4147   ** adequate. No need for a binary search. */
4148   for(i=0; i<nOpt; i++){
4149     if( sqlite3StrNICmp(zOptName, azCompileOpt[i], n)==0
4150      && sqlite3IsIdChar((unsigned char)azCompileOpt[i][n])==0
4151     ){
4152       return 1;
4153     }
4154   }
4155   return 0;
4156 }
4157 
4158 /*
4159 ** Return the N-th compile-time option string.  If N is out of range,
4160 ** return a NULL pointer.
4161 */
4162 const char *sqlite3_compileoption_get(int N){
4163   int nOpt;
4164   const char **azCompileOpt;
4165   azCompileOpt = sqlite3CompileOptions(&nOpt);
4166   if( N>=0 && N<nOpt ){
4167     return azCompileOpt[N];
4168   }
4169   return 0;
4170 }
4171 #endif /* SQLITE_OMIT_COMPILEOPTION_DIAGS */
4172