Index: third_party/sqlite/sqlite-src-3070603/src/mutex_w32.c |
diff --git a/third_party/sqlite/sqlite-src-3070603/src/mutex_w32.c b/third_party/sqlite/sqlite-src-3070603/src/mutex_w32.c |
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+/* |
+** 2007 August 14 |
+** |
+** The author disclaims copyright to this source code. In place of |
+** a legal notice, here is a blessing: |
+** |
+** May you do good and not evil. |
+** May you find forgiveness for yourself and forgive others. |
+** May you share freely, never taking more than you give. |
+** |
+************************************************************************* |
+** This file contains the C functions that implement mutexes for win32 |
+*/ |
+#include "sqliteInt.h" |
+ |
+/* |
+** The code in this file is only used if we are compiling multithreaded |
+** on a win32 system. |
+*/ |
+#ifdef SQLITE_MUTEX_W32 |
+ |
+/* |
+** Each recursive mutex is an instance of the following structure. |
+*/ |
+struct sqlite3_mutex { |
+ CRITICAL_SECTION mutex; /* Mutex controlling the lock */ |
+ int id; /* Mutex type */ |
+#ifdef SQLITE_DEBUG |
+ volatile int nRef; /* Number of enterances */ |
+ volatile DWORD owner; /* Thread holding this mutex */ |
+ int trace; /* True to trace changes */ |
+#endif |
+}; |
+#define SQLITE_W32_MUTEX_INITIALIZER { 0 } |
+#ifdef SQLITE_DEBUG |
+#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0, 0L, (DWORD)0, 0 } |
+#else |
+#define SQLITE3_MUTEX_INITIALIZER { SQLITE_W32_MUTEX_INITIALIZER, 0 } |
+#endif |
+ |
+/* |
+** Return true (non-zero) if we are running under WinNT, Win2K, WinXP, |
+** or WinCE. Return false (zero) for Win95, Win98, or WinME. |
+** |
+** Here is an interesting observation: Win95, Win98, and WinME lack |
+** the LockFileEx() API. But we can still statically link against that |
+** API as long as we don't call it win running Win95/98/ME. A call to |
+** this routine is used to determine if the host is Win95/98/ME or |
+** WinNT/2K/XP so that we will know whether or not we can safely call |
+** the LockFileEx() API. |
+** |
+** mutexIsNT() is only used for the TryEnterCriticalSection() API call, |
+** which is only available if your application was compiled with |
+** _WIN32_WINNT defined to a value >= 0x0400. Currently, the only |
+** call to TryEnterCriticalSection() is #ifdef'ed out, so #ifdef |
+** this out as well. |
+*/ |
+#if 0 |
+#if SQLITE_OS_WINCE |
+# define mutexIsNT() (1) |
+#else |
+ static int mutexIsNT(void){ |
+ static int osType = 0; |
+ if( osType==0 ){ |
+ OSVERSIONINFO sInfo; |
+ sInfo.dwOSVersionInfoSize = sizeof(sInfo); |
+ GetVersionEx(&sInfo); |
+ osType = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1; |
+ } |
+ return osType==2; |
+ } |
+#endif /* SQLITE_OS_WINCE */ |
+#endif |
+ |
+#ifdef SQLITE_DEBUG |
+/* |
+** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are |
+** intended for use only inside assert() statements. |
+*/ |
+static int winMutexHeld(sqlite3_mutex *p){ |
+ return p->nRef!=0 && p->owner==GetCurrentThreadId(); |
+} |
+static int winMutexNotheld2(sqlite3_mutex *p, DWORD tid){ |
+ return p->nRef==0 || p->owner!=tid; |
+} |
+static int winMutexNotheld(sqlite3_mutex *p){ |
+ DWORD tid = GetCurrentThreadId(); |
+ return winMutexNotheld2(p, tid); |
+} |
+#endif |
+ |
+ |
+/* |
+** Initialize and deinitialize the mutex subsystem. |
+*/ |
+static sqlite3_mutex winMutex_staticMutexes[6] = { |
+ SQLITE3_MUTEX_INITIALIZER, |
+ SQLITE3_MUTEX_INITIALIZER, |
+ SQLITE3_MUTEX_INITIALIZER, |
+ SQLITE3_MUTEX_INITIALIZER, |
+ SQLITE3_MUTEX_INITIALIZER, |
+ SQLITE3_MUTEX_INITIALIZER |
+}; |
+static int winMutex_isInit = 0; |
+/* As winMutexInit() and winMutexEnd() are called as part |
+** of the sqlite3_initialize and sqlite3_shutdown() |
+** processing, the "interlocked" magic is probably not |
+** strictly necessary. |
+*/ |
+static long winMutex_lock = 0; |
+ |
+static int winMutexInit(void){ |
+ /* The first to increment to 1 does actual initialization */ |
+ if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){ |
+ int i; |
+ for(i=0; i<ArraySize(winMutex_staticMutexes); i++){ |
+ InitializeCriticalSection(&winMutex_staticMutexes[i].mutex); |
+ } |
+ winMutex_isInit = 1; |
+ }else{ |
+ /* Someone else is in the process of initing the static mutexes */ |
+ while( !winMutex_isInit ){ |
+ Sleep(1); |
+ } |
+ } |
+ return SQLITE_OK; |
+} |
+ |
+static int winMutexEnd(void){ |
+ /* The first to decrement to 0 does actual shutdown |
+ ** (which should be the last to shutdown.) */ |
+ if( InterlockedCompareExchange(&winMutex_lock, 0, 1)==1 ){ |
+ if( winMutex_isInit==1 ){ |
+ int i; |
+ for(i=0; i<ArraySize(winMutex_staticMutexes); i++){ |
+ DeleteCriticalSection(&winMutex_staticMutexes[i].mutex); |
+ } |
+ winMutex_isInit = 0; |
+ } |
+ } |
+ return SQLITE_OK; |
+} |
+ |
+/* |
+** The sqlite3_mutex_alloc() routine allocates a new |
+** mutex and returns a pointer to it. If it returns NULL |
+** that means that a mutex could not be allocated. SQLite |
+** will unwind its stack and return an error. The argument |
+** to sqlite3_mutex_alloc() is one of these integer constants: |
+** |
+** <ul> |
+** <li> SQLITE_MUTEX_FAST |
+** <li> SQLITE_MUTEX_RECURSIVE |
+** <li> SQLITE_MUTEX_STATIC_MASTER |
+** <li> SQLITE_MUTEX_STATIC_MEM |
+** <li> SQLITE_MUTEX_STATIC_MEM2 |
+** <li> SQLITE_MUTEX_STATIC_PRNG |
+** <li> SQLITE_MUTEX_STATIC_LRU |
+** <li> SQLITE_MUTEX_STATIC_PMEM |
+** </ul> |
+** |
+** The first two constants cause sqlite3_mutex_alloc() to create |
+** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE |
+** is used but not necessarily so when SQLITE_MUTEX_FAST is used. |
+** The mutex implementation does not need to make a distinction |
+** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does |
+** not want to. But SQLite will only request a recursive mutex in |
+** cases where it really needs one. If a faster non-recursive mutex |
+** implementation is available on the host platform, the mutex subsystem |
+** might return such a mutex in response to SQLITE_MUTEX_FAST. |
+** |
+** The other allowed parameters to sqlite3_mutex_alloc() each return |
+** a pointer to a static preexisting mutex. Six static mutexes are |
+** used by the current version of SQLite. Future versions of SQLite |
+** may add additional static mutexes. Static mutexes are for internal |
+** use by SQLite only. Applications that use SQLite mutexes should |
+** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or |
+** SQLITE_MUTEX_RECURSIVE. |
+** |
+** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST |
+** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() |
+** returns a different mutex on every call. But for the static |
+** mutex types, the same mutex is returned on every call that has |
+** the same type number. |
+*/ |
+static sqlite3_mutex *winMutexAlloc(int iType){ |
+ sqlite3_mutex *p; |
+ |
+ switch( iType ){ |
+ case SQLITE_MUTEX_FAST: |
+ case SQLITE_MUTEX_RECURSIVE: { |
+ p = sqlite3MallocZero( sizeof(*p) ); |
+ if( p ){ |
+#ifdef SQLITE_DEBUG |
+ p->id = iType; |
+#endif |
+ InitializeCriticalSection(&p->mutex); |
+ } |
+ break; |
+ } |
+ default: { |
+ assert( winMutex_isInit==1 ); |
+ assert( iType-2 >= 0 ); |
+ assert( iType-2 < ArraySize(winMutex_staticMutexes) ); |
+ p = &winMutex_staticMutexes[iType-2]; |
+#ifdef SQLITE_DEBUG |
+ p->id = iType; |
+#endif |
+ break; |
+ } |
+ } |
+ return p; |
+} |
+ |
+ |
+/* |
+** This routine deallocates a previously |
+** allocated mutex. SQLite is careful to deallocate every |
+** mutex that it allocates. |
+*/ |
+static void winMutexFree(sqlite3_mutex *p){ |
+ assert( p ); |
+ assert( p->nRef==0 && p->owner==0 ); |
+ assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ); |
+ DeleteCriticalSection(&p->mutex); |
+ sqlite3_free(p); |
+} |
+ |
+/* |
+** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt |
+** to enter a mutex. If another thread is already within the mutex, |
+** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return |
+** SQLITE_BUSY. The sqlite3_mutex_try() interface returns SQLITE_OK |
+** upon successful entry. Mutexes created using SQLITE_MUTEX_RECURSIVE can |
+** be entered multiple times by the same thread. In such cases the, |
+** mutex must be exited an equal number of times before another thread |
+** can enter. If the same thread tries to enter any other kind of mutex |
+** more than once, the behavior is undefined. |
+*/ |
+static void winMutexEnter(sqlite3_mutex *p){ |
+#ifdef SQLITE_DEBUG |
+ DWORD tid = GetCurrentThreadId(); |
+ assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) ); |
+#endif |
+ EnterCriticalSection(&p->mutex); |
+#ifdef SQLITE_DEBUG |
+ assert( p->nRef>0 || p->owner==0 ); |
+ p->owner = tid; |
+ p->nRef++; |
+ if( p->trace ){ |
+ printf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); |
+ } |
+#endif |
+} |
+static int winMutexTry(sqlite3_mutex *p){ |
+#ifndef NDEBUG |
+ DWORD tid = GetCurrentThreadId(); |
+#endif |
+ int rc = SQLITE_BUSY; |
+ assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) ); |
+ /* |
+ ** The sqlite3_mutex_try() routine is very rarely used, and when it |
+ ** is used it is merely an optimization. So it is OK for it to always |
+ ** fail. |
+ ** |
+ ** The TryEnterCriticalSection() interface is only available on WinNT. |
+ ** And some windows compilers complain if you try to use it without |
+ ** first doing some #defines that prevent SQLite from building on Win98. |
+ ** For that reason, we will omit this optimization for now. See |
+ ** ticket #2685. |
+ */ |
+#if 0 |
+ if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){ |
+ p->owner = tid; |
+ p->nRef++; |
+ rc = SQLITE_OK; |
+ } |
+#else |
+ UNUSED_PARAMETER(p); |
+#endif |
+#ifdef SQLITE_DEBUG |
+ if( rc==SQLITE_OK && p->trace ){ |
+ printf("try mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); |
+ } |
+#endif |
+ return rc; |
+} |
+ |
+/* |
+** The sqlite3_mutex_leave() routine exits a mutex that was |
+** previously entered by the same thread. The behavior |
+** is undefined if the mutex is not currently entered or |
+** is not currently allocated. SQLite will never do either. |
+*/ |
+static void winMutexLeave(sqlite3_mutex *p){ |
+#ifndef NDEBUG |
+ DWORD tid = GetCurrentThreadId(); |
+ assert( p->nRef>0 ); |
+ assert( p->owner==tid ); |
+ p->nRef--; |
+ if( p->nRef==0 ) p->owner = 0; |
+ assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE ); |
+#endif |
+ LeaveCriticalSection(&p->mutex); |
+#ifdef SQLITE_DEBUG |
+ if( p->trace ){ |
+ printf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef); |
+ } |
+#endif |
+} |
+ |
+sqlite3_mutex_methods const *sqlite3DefaultMutex(void){ |
+ static const sqlite3_mutex_methods sMutex = { |
+ winMutexInit, |
+ winMutexEnd, |
+ winMutexAlloc, |
+ winMutexFree, |
+ winMutexEnter, |
+ winMutexTry, |
+ winMutexLeave, |
+#ifdef SQLITE_DEBUG |
+ winMutexHeld, |
+ winMutexNotheld |
+#else |
+ 0, |
+ 0 |
+#endif |
+ }; |
+ |
+ return &sMutex; |
+} |
+#endif /* SQLITE_MUTEX_W32 */ |