diff -r c7b4237fff50 -r 03a67e41afbc extensions/sqlite/sqlite-source/mutex_w32.c --- a/extensions/sqlite/sqlite-source/mutex_w32.c Fri Mar 28 06:21:34 2008 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,208 +0,0 @@ -/* -** 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 -** -** $Id$ -*/ -#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 */ - int nRef; /* Number of enterances */ - DWORD owner; /* Thread holding this mutex */ -}; - -/* -** 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. -*/ -#if 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 /* OS_WINCE */ - - -/* -** 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: -** -** -** -** 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. Three 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. -*/ -sqlite3_mutex *sqlite3_mutex_alloc(int iType){ - sqlite3_mutex *p; - - switch( iType ){ - case SQLITE_MUTEX_FAST: - case SQLITE_MUTEX_RECURSIVE: { - p = sqlite3MallocZero( sizeof(*p) ); - if( p ){ - p->id = iType; - InitializeCriticalSection(&p->mutex); - } - break; - } - default: { - static sqlite3_mutex staticMutexes[5]; - static int isInit = 0; - while( !isInit ){ - static long lock = 0; - if( InterlockedIncrement(&lock)==1 ){ - int i; - for(i=0; i= 0 ); - assert( iType-2 < sizeof(staticMutexes)/sizeof(staticMutexes[0]) ); - p = &staticMutexes[iType-2]; - p->id = iType; - break; - } - } - return p; -} - - -/* -** This routine deallocates a previously -** allocated mutex. SQLite is careful to deallocate every -** mutex that it allocates. -*/ -void sqlite3_mutex_free(sqlite3_mutex *p){ - assert( p ); - assert( p->nRef==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. -*/ -void sqlite3_mutex_enter(sqlite3_mutex *p){ - assert( p ); - assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); - EnterCriticalSection(&p->mutex); - p->owner = GetCurrentThreadId(); - p->nRef++; -} -int sqlite3_mutex_try(sqlite3_mutex *p){ - int rc; - assert( p ); - assert( p->id==SQLITE_MUTEX_RECURSIVE || sqlite3_mutex_notheld(p) ); - if( mutexIsNT() && TryEnterCriticalSection(&p->mutex) ){ - p->owner = GetCurrentThreadId(); - p->nRef++; - rc = SQLITE_OK; - }else{ - rc = SQLITE_BUSY; - } - 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. -*/ -void sqlite3_mutex_leave(sqlite3_mutex *p){ - assert( p->nRef>0 ); - assert( p->owner==GetCurrentThreadId() ); - p->nRef--; - assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE ); - LeaveCriticalSection(&p->mutex); -} - -/* -** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are -** intended for use only inside assert() statements. -*/ -int sqlite3_mutex_held(sqlite3_mutex *p){ - return p==0 || (p->nRef!=0 && p->owner==GetCurrentThreadId()); -} -int sqlite3_mutex_notheld(sqlite3_mutex *p){ - return p==0 || p->nRef==0 || p->owner!=GetCurrentThreadId(); -} -#endif /* SQLITE_MUTEX_W32 */