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/*
* Copyright (C) 2009 Andrzej K. Haczewski <ahaczewski@gmail.com>
*
* DISCLAMER: The implementation is Git-specific, it is subset of original
* Pthreads API, without lots of other features that Git doesn't use.
* Git also makes sure that the passed arguments are valid, so there's
* no need for double-checking.
*/
#include "../../git-compat-util.h"
#include "pthread.h"
#include <errno.h>
#include <limits.h>
static unsigned __stdcall win32_start_routine(void *arg)
{
pthread_t *thread = arg;
thread->arg = thread->start_routine(thread->arg);
return 0;
}
int pthread_create(pthread_t *thread, const void *unused,
void *(*start_routine)(void*), void *arg)
{
thread->arg = arg;
thread->start_routine = start_routine;
thread->handle = (HANDLE)
_beginthreadex(NULL, 0, win32_start_routine, thread, 0, NULL);
if (!thread->handle)
return errno;
else
return 0;
}
int win32_pthread_join(pthread_t *thread, void **value_ptr)
{
DWORD result = WaitForSingleObject(thread->handle, INFINITE);
switch (result) {
case WAIT_OBJECT_0:
if (value_ptr)
*value_ptr = thread->arg;
return 0;
case WAIT_ABANDONED:
return EINVAL;
default:
return err_win_to_posix(GetLastError());
}
}
int pthread_cond_init(pthread_cond_t *cond, const void *unused)
{
cond->waiters = 0;
cond->sema = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
if (!cond->sema)
die("CreateSemaphore() failed");
return 0;
}
int pthread_cond_destroy(pthread_cond_t *cond)
{
CloseHandle(cond->sema);
cond->sema = NULL;
return 0;
}
int pthread_cond_wait(pthread_cond_t *cond, CRITICAL_SECTION *mutex)
{
InterlockedIncrement(&cond->waiters);
/*
* Unlock external mutex and wait for signal.
* NOTE: we've held mutex locked long enough to increment
* waiters count above, so there's no problem with
* leaving mutex unlocked before we wait on semaphore.
*/
LeaveCriticalSection(mutex);
/* let's wait - ignore return value */
WaitForSingleObject(cond->sema, INFINITE);
/* we're done waiting, so make sure we decrease waiters count */
InterlockedDecrement(&cond->waiters);
/* lock external mutex again */
EnterCriticalSection(mutex);
return 0;
}
int pthread_cond_signal(pthread_cond_t *cond)
{
/*
* Access to waiters count is atomic; see "Interlocked Variable Access"
* http://msdn.microsoft.com/en-us/library/ms684122(VS.85).aspx
*/
int have_waiters = cond->waiters > 0;
/*
* Signal only when there are waiters
*/
if (have_waiters)
return ReleaseSemaphore(cond->sema, 1, NULL) ?
0 : err_win_to_posix(GetLastError());
else
return 0;
}
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