[PATCH 1/2] compat/win32/pthread: add pthread_once()

[Matheus Tavares <matheus.bernardino@usp.br>]

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---

Note: the pthread_once() function is adapted from:
https://git.libav.org/?p=libav.git;a=commitdiff;h=b22693b06d1e5d73454a65c203b4d31c1ca5b69a

Which is LGPLv2.1. Should I add any notice/acknowledgment somewhere,
besides the comment I added above the function?

 compat/win32/pthread.c | 22 ++++++++++++++++++++++
 compat/win32/pthread.h |  5 +++++
 thread-utils.c         | 11 +++++++++++
 thread-utils.h         |  6 ++++++
 4 files changed, 44 insertions(+)

diff --git a/compat/win32/pthread.c b/compat/win32/pthread.c
index 2e7eead42c..5a7ecbd999 100644
--- a/compat/win32/pthread.c
+++ b/compat/win32/pthread.c
@@ -56,3 +56,25 @@ pthread_t pthread_self(void)
 	t.tid = GetCurrentThreadId();
 	return t;
 }
+
+/* Adapted from libav's compat/w32pthreads.h. */
+int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
+{
+	BOOL pending = FALSE;
+	int ret = 0;
+
+	if(!InitOnceBeginInitialize(once_control, 0, &pending, NULL)) {
+		ret = err_win_to_posix(GetLastError());
+		goto out;
+	}
+
+	if (pending)
+		init_routine();
+
+	if(!InitOnceComplete(once_control, 0, NULL))
+		ret = err_win_to_posix(GetLastError());
+
+out:
+	/* POSIX doesn't allow pthread_once() to return EINTR */
+	return ret == EINTR ? EIO : ret;
+}
diff --git a/compat/win32/pthread.h b/compat/win32/pthread.h
index 737983d00b..c50f1e89c7 100644
--- a/compat/win32/pthread.h
+++ b/compat/win32/pthread.h
@@ -40,6 +40,11 @@ typedef int pthread_mutexattr_t;
 #define pthread_cond_signal WakeConditionVariable
 #define pthread_cond_broadcast WakeAllConditionVariable
 
+#define pthread_once_t INIT_ONCE
+
+#define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
+int pthread_once(pthread_once_t *once_control, void (*init_routine)(void));
+
 /*
  * Simple thread creation implementation using pthread API
  */
diff --git a/thread-utils.c b/thread-utils.c
index 5329845691..937deb3f2e 100644
--- a/thread-utils.c
+++ b/thread-utils.c
@@ -122,4 +122,15 @@ int dummy_pthread_join(pthread_t pthread, void **retval)
 	return ENOSYS;
 }
 
+int nothreads_pthread_once(pthread_once_t *once_control,
+			   void (*init_routine)(void))
+{
+	if (*once_control == 1)
+		return 0;
+
+	init_routine();
+	*once_control = 1;
+	return 0;
+}
+
 #endif
diff --git a/thread-utils.h b/thread-utils.h
index 4961487ed9..bab9dc5e4d 100644
--- a/thread-utils.h
+++ b/thread-utils.h
@@ -19,6 +19,7 @@
 #define pthread_mutex_t int
 #define pthread_cond_t int
 #define pthread_key_t int
+#define pthread_once_t int
 
 #define pthread_mutex_init(mutex, attr) dummy_pthread_init(mutex)
 #define pthread_mutex_lock(mutex)
@@ -48,6 +49,11 @@ int dummy_pthread_join(pthread_t pthread, void **retval);
 
 int dummy_pthread_init(void *);
 
+#define PTHREAD_ONCE_INIT 0
+int nothreads_pthread_once(pthread_once_t *once_control,
+			   void (*init_routine)(void));
+#define pthread_once(once, routine) nothreads_pthread_once(once, routine)
+
 #endif
 
 int online_cpus(void);
-- 
2.26.2