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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 14:07:11 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-13 14:07:11 +0000
commit63847496f14c813a5d80efd5b7de0f1294ffe1e3 (patch)
tree01c7571c7c762ceee70638549a99834fdd7c411b /src/mutex_w32.c
parentInitial commit. (diff)
downloadsqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.tar.xz
sqlite3-63847496f14c813a5d80efd5b7de0f1294ffe1e3.zip
Adding upstream version 3.45.1.upstream/3.45.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/mutex_w32.c')
-rw-r--r--src/mutex_w32.c399
1 files changed, 399 insertions, 0 deletions
diff --git a/src/mutex_w32.c b/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"
+
+#if SQLITE_OS_WIN
+/*
+** Include code that is common to all os_*.c files
+*/
+#include "os_common.h"
+
+/*
+** Include the header file for the Windows VFS.
+*/
+#include "os_win.h"
+#endif
+
+/*
+** 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 entrances */
+ volatile DWORD owner; /* Thread holding this mutex */
+ volatile LONG trace; /* True to trace changes */
+#endif
+};
+
+/*
+** These are the initializer values used when declaring a "static" mutex
+** on Win32. It should be noted that all mutexes require initialization
+** on the Win32 platform.
+*/
+#define SQLITE_W32_MUTEX_INITIALIZER { 0 }
+
+#ifdef SQLITE_DEBUG
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id, \
+ 0L, (DWORD)0, 0 }
+#else
+#define SQLITE3_MUTEX_INITIALIZER(id) { SQLITE_W32_MUTEX_INITIALIZER, id }
+#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
+
+/*
+** Try to provide a memory barrier operation, needed for initialization
+** and also for the xShmBarrier method of the VFS in cases when SQLite is
+** compiled without mutexes (SQLITE_THREADSAFE=0).
+*/
+void sqlite3MemoryBarrier(void){
+#if defined(SQLITE_MEMORY_BARRIER)
+ SQLITE_MEMORY_BARRIER;
+#elif defined(__GNUC__)
+ __sync_synchronize();
+#elif MSVC_VERSION>=1400
+ _ReadWriteBarrier();
+#elif defined(MemoryBarrier)
+ MemoryBarrier();
+#endif
+}
+
+/*
+** Initialize and deinitialize the mutex subsystem.
+*/
+static sqlite3_mutex winMutex_staticMutexes[] = {
+ SQLITE3_MUTEX_INITIALIZER(2),
+ SQLITE3_MUTEX_INITIALIZER(3),
+ SQLITE3_MUTEX_INITIALIZER(4),
+ SQLITE3_MUTEX_INITIALIZER(5),
+ SQLITE3_MUTEX_INITIALIZER(6),
+ SQLITE3_MUTEX_INITIALIZER(7),
+ SQLITE3_MUTEX_INITIALIZER(8),
+ SQLITE3_MUTEX_INITIALIZER(9),
+ SQLITE3_MUTEX_INITIALIZER(10),
+ SQLITE3_MUTEX_INITIALIZER(11),
+ SQLITE3_MUTEX_INITIALIZER(12),
+ SQLITE3_MUTEX_INITIALIZER(13)
+};
+
+static int winMutex_isInit = 0;
+static int winMutex_isNt = -1; /* <0 means "need to query" */
+
+/* As the winMutexInit() and winMutexEnd() functions are called as part
+** of the sqlite3_initialize() and sqlite3_shutdown() processing, the
+** "interlocked" magic used here is probably not strictly necessary.
+*/
+static LONG SQLITE_WIN32_VOLATILE winMutex_lock = 0;
+
+int sqlite3_win32_is_nt(void); /* os_win.c */
+void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */
+
+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++){
+#if SQLITE_OS_WINRT
+ InitializeCriticalSectionEx(&winMutex_staticMutexes[i].mutex, 0, 0);
+#else
+ InitializeCriticalSection(&winMutex_staticMutexes[i].mutex);
+#endif
+ }
+ winMutex_isInit = 1;
+ }else{
+ /* Another thread is (in the process of) initializing the static
+ ** mutexes */
+ while( !winMutex_isInit ){
+ sqlite3_win32_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_MAIN
+** <li> SQLITE_MUTEX_STATIC_MEM
+** <li> SQLITE_MUTEX_STATIC_OPEN
+** <li> SQLITE_MUTEX_STATIC_PRNG
+** <li> SQLITE_MUTEX_STATIC_LRU
+** <li> SQLITE_MUTEX_STATIC_PMEM
+** <li> SQLITE_MUTEX_STATIC_APP1
+** <li> SQLITE_MUTEX_STATIC_APP2
+** <li> SQLITE_MUTEX_STATIC_APP3
+** <li> SQLITE_MUTEX_STATIC_VFS1
+** <li> SQLITE_MUTEX_STATIC_VFS2
+** <li> SQLITE_MUTEX_STATIC_VFS3
+** </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;
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_DYNAMIC
+ p->trace = 1;
+#endif
+#endif
+#if SQLITE_OS_WINRT
+ InitializeCriticalSectionEx(&p->mutex, 0, 0);
+#else
+ InitializeCriticalSection(&p->mutex);
+#endif
+ }
+ break;
+ }
+ default: {
+#ifdef SQLITE_ENABLE_API_ARMOR
+ if( iType-2<0 || iType-2>=ArraySize(winMutex_staticMutexes) ){
+ (void)SQLITE_MISUSE_BKPT;
+ return 0;
+ }
+#endif
+ p = &winMutex_staticMutexes[iType-2];
+#ifdef SQLITE_DEBUG
+#ifdef SQLITE_WIN32_MUTEX_TRACE_STATIC
+ InterlockedCompareExchange(&p->trace, 1, 0);
+#endif
+#endif
+ break;
+ }
+ }
+ assert( p==0 || p->id==iType );
+ 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 );
+ if( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE ){
+ DeleteCriticalSection(&p->mutex);
+ sqlite3_free(p);
+ }else{
+#ifdef SQLITE_ENABLE_API_ARMOR
+ (void)SQLITE_MISUSE_BKPT;
+#endif
+ }
+}
+
+/*
+** 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){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+ DWORD tid = GetCurrentThreadId();
+#endif
+#ifdef SQLITE_DEBUG
+ assert( p );
+ assert( p->id==SQLITE_MUTEX_RECURSIVE || winMutexNotheld2(p, tid) );
+#else
+ assert( p );
+#endif
+ assert( winMutex_isInit==1 );
+ EnterCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+ assert( p->nRef>0 || p->owner==0 );
+ p->owner = tid;
+ p->nRef++;
+ if( p->trace ){
+ OSTRACE(("ENTER-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+ tid, p->id, p, p->trace, p->nRef));
+ }
+#endif
+}
+
+static int winMutexTry(sqlite3_mutex *p){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+ DWORD tid = GetCurrentThreadId();
+#endif
+ int rc = SQLITE_BUSY;
+ assert( p );
+ 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 defined(_WIN32_WINNT) && _WIN32_WINNT >= 0x0400
+ assert( winMutex_isInit==1 );
+ assert( winMutex_isNt>=-1 && winMutex_isNt<=1 );
+ if( winMutex_isNt<0 ){
+ winMutex_isNt = sqlite3_win32_is_nt();
+ }
+ assert( winMutex_isNt==0 || winMutex_isNt==1 );
+ if( winMutex_isNt && TryEnterCriticalSection(&p->mutex) ){
+#ifdef SQLITE_DEBUG
+ p->owner = tid;
+ p->nRef++;
+#endif
+ rc = SQLITE_OK;
+ }
+#else
+ UNUSED_PARAMETER(p);
+#endif
+#ifdef SQLITE_DEBUG
+ if( p->trace ){
+ OSTRACE(("TRY-MUTEX tid=%lu, mutex(%d)=%p (%d), owner=%lu, nRef=%d, rc=%s\n",
+ tid, p->id, p, p->trace, p->owner, p->nRef, sqlite3ErrName(rc)));
+ }
+#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){
+#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
+ DWORD tid = GetCurrentThreadId();
+#endif
+ assert( p );
+#ifdef SQLITE_DEBUG
+ 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
+ assert( winMutex_isInit==1 );
+ LeaveCriticalSection(&p->mutex);
+#ifdef SQLITE_DEBUG
+ if( p->trace ){
+ OSTRACE(("LEAVE-MUTEX tid=%lu, mutex(%d)=%p (%d), nRef=%d\n",
+ tid, p->id, 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 */