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Unified Diff: third_party/sqlite/src/mutex_w32.c

Issue 3108030: Move bundled copy of sqlite one level deeper to better separate it... (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src/
Patch Set: Created 10 years, 4 months ago
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Index: third_party/sqlite/src/mutex_w32.c
===================================================================
--- third_party/sqlite/src/mutex_w32.c (revision 56608)
+++ third_party/sqlite/src/mutex_w32.c (working copy)
@@ -1,284 +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: mutex_w32.c,v 1.18 2009/08/10 03:23:21 shane Exp $
-*/
-#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.
-**
-** 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 winMutexNotheld(sqlite3_mutex *p){
- return p->nRef==0 || p->owner!=GetCurrentThreadId();
-}
-#endif
-
-
-/*
-** Initialize and deinitialize the mutex subsystem.
-*/
-static sqlite3_mutex winMutex_staticMutexes[6];
-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_LRU2
-** </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 ){
- p->id = iType;
- InitializeCriticalSection(&p->mutex);
- }
- break;
- }
- default: {
- assert( winMutex_isInit==1 );
- assert( iType-2 >= 0 );
- assert( iType-2 < ArraySize(winMutex_staticMutexes) );
- p = &winMutex_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.
-*/
-static void winMutexFree(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.
-*/
-static void winMutexEnter(sqlite3_mutex *p){
- assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld(p) );
- EnterCriticalSection(&p->mutex);
- p->owner = GetCurrentThreadId();
- p->nRef++;
-}
-static int winMutexTry(sqlite3_mutex *p){
- int rc = SQLITE_BUSY;
- assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld(p) );
- /*
- ** 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 = GetCurrentThreadId();
- p->nRef++;
- rc = SQLITE_OK;
- }
-#else
- UNUSED_PARAMETER(p);
-#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){
- assert( p->nRef>0 );
- assert( p->owner==GetCurrentThreadId() );
- p->nRef--;
- assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
- LeaveCriticalSection(&p->mutex);
-}
-
-sqlite3_mutex_methods *sqlite3DefaultMutex(void){
- static 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 */
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