win32: replace pthread_cond_*() with much simpler code

The Win32 CONDITION_VARIABLE has better performance and is easier to
maintain, as the code is a lot shorter now (the semantics of the
CONDITION_VARIABLE matches the pthread_cond_t very well).

Note: CONDITION_VARIABLE is not available in Windows XP and below,
but the declared minimal Windows version required to build and run
Git for Windows is Windows Vista (which is also beyond its
end-of-life, but for less long than Windows XP), so that's okay.

Signed-off-by: Loo Rong Jie <loorongjie@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 21 deletions

diff --git a/compat/win32/pthread.h b/compat/win32/pthread.h
index 1c164088fb..c6cb8dd219 100644
--- a/compat/win32/pthread.h
+++ b/compat/win32/pthread.h
@@ -32,27 +32,13 @@ typedef int pthread_mutexattr_t;
 #define pthread_mutexattr_settype(a, t) 0
 #define PTHREAD_MUTEX_RECURSIVE 0
 
-/*
- * Implement simple condition variable for Windows threads, based on ACE
- * implementation.
- *
- * See original implementation: http://bit.ly/1vkDjo
- * ACE homepage: http://www.cse.wustl.edu/~schmidt/ACE.html
- * See also: http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
- */
-typedef struct {
-	LONG waiters;
-	int was_broadcast;
-	CRITICAL_SECTION waiters_lock;
-	HANDLE sema;
-	HANDLE continue_broadcast;
-} pthread_cond_t;
-
-extern int pthread_cond_init(pthread_cond_t *cond, const void *unused);
-extern int pthread_cond_destroy(pthread_cond_t *cond);
-extern int pthread_cond_wait(pthread_cond_t *cond, CRITICAL_SECTION *mutex);
-extern int pthread_cond_signal(pthread_cond_t *cond);
-extern int pthread_cond_broadcast(pthread_cond_t *cond);
+#define pthread_cond_t CONDITION_VARIABLE
+
+#define pthread_cond_init(a,b) InitializeConditionVariable((a))
+#define pthread_cond_destroy(a) do {} while (0)
+#define pthread_cond_wait(a,b) return_0(SleepConditionVariableCS((a), (b), INFINITE))
+#define pthread_cond_signal WakeConditionVariable
+#define pthread_cond_broadcast WakeAllConditionVariable
 
 /*
  * Simple thread creation implementation using pthread API