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Added implementations for sqliteOsEnterMutex() and sqliteOsLeaveMutex(). (CVS 348)

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FossilOrigin-Name: f8a026a3ca14ef0b0d562029dd6b184f060457f4
This commit is contained in:
drh
2002-01-15 18:39:43 +00:00
parent 1ab4300ebc
commit a297b5c3cf
9 changed files with 98 additions and 32 deletions
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59
src/os.c
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@@ -19,7 +19,13 @@
#ifndef OS_UNIX
# ifndef OS_WIN
# define OS_UNIX 1
# if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)
# define OS_WIN 1
# define OS_UNIX 0
# else
# define OS_WIN 0
# define OS_UNIX 1
# endif
# else
# define OS_UNIX 0
# endif
@@ -743,6 +749,31 @@ int sqliteOsSleep(int ms){
#endif
}
/*
** Macros used to determine whether or not to use threads. The
** SQLITE_UNIX_THREADS macro is defined if we are synchronizing for
** Posix threads and SQLITE_W32_THREADS is defined if we are
** synchronizing using Win32 threads.
*/
#if OS_UNIX && defined(THREADSAFE) && THREADSAFE
# include <pthread.h>
# define SQLITE_UNIX_THREADS 1
#endif
#if OS_WIN && defined(THREADSAFE) && THREADSAFE
# define SQLITE_W32_THREADS 1
#endif
/*
** Static variables used for thread synchronization
*/
static int inMutex = 0;
#ifdef SQLITE_UNIX_THREADS
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
#ifdef SQLITE_W32_THREADS
static CRITICAL_SECTION cs;
#endif
/*
** The following pair of routine implement mutual exclusion for
** multi-threaded processes. Only a single thread is allowed to
@@ -750,16 +781,34 @@ int sqliteOsSleep(int ms){
**
** SQLite uses only a single Mutex. There is not much critical
** code and what little there is executes quickly and without blocking.
**
****** TBD: The mutex is currently unimplemented. Until it is
****** implemented, SQLite is not threadsafe.
*/
static int inMutex = 0;
void sqliteOsEnterMutex(){
#ifdef SQLITE_UNIX_THREADS
pthread_mutex_lock(&mutex);
#endif
#ifdef SQLITE_W32_THREADS
static int isInit = 0;
while( !isInit ){
static long lock = 0;
if( InterlockedIncrement(&lock)==1 ){
InitializeCriticalSection(&cs);
isInit = 1;
}else{
Sleep(1);
}
}
EnterCriticalSection(&cs);
#endif
assert( !inMutex );
inMutex = 1;
}
void sqliteOsLeaveMutex(){
assert( inMutex );
inMutex = 0;
#ifdef SQLITE_UNIX_THREADS
pthread_mutex_unlock(&mutex);
#endif
#ifdef SQLITE_W32_THREADS
LeaveCriticalSection(&cs);
#endif
}