[vlc-commits] Win32: emulate static condition variables

[Rémi Denis-Courmont]

vlc | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Thu Aug 18 18:14:41 2011 +0300| [4707b4f4ac4b643900210be6169913f7d550f2af] | committer: Rémi Denis-Courmont

Win32: emulate static condition variables

This is really poor implementation, but it is not really used.

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=4707b4f4ac4b643900210be6169913f7d550f2af
---

 include/vlc_threads.h |    1 +
 src/win32/thread.c    |   29 ++++++++++++++++++++++-------
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/include/vlc_threads.h b/include/vlc_threads.h
index dfe4359..fea79be 100644
--- a/include/vlc_threads.h
+++ b/include/vlc_threads.h
@@ -144,6 +144,7 @@ typedef struct
     HANDLE   handle;
     unsigned clock;
 } vlc_cond_t;
+#define VLC_STATIC_COND { 0, 0, 0 }
 
 typedef HANDLE  vlc_sem_t;
 
diff --git a/src/win32/thread.c b/src/win32/thread.c
index 6831cbe..99e54b5 100644
--- a/src/win32/thread.c
+++ b/src/win32/thread.c
@@ -232,8 +232,8 @@ void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
 /*** Condition variables ***/
 enum
 {
+    CLOCK_REALTIME=0, /* must be zero for VLC_STATIC_COND */
     CLOCK_MONOTONIC,
-    CLOCK_REALTIME,
 };
 
 static void vlc_cond_init_common (vlc_cond_t *p_condvar, unsigned clock)
@@ -262,16 +262,19 @@ void vlc_cond_destroy (vlc_cond_t *p_condvar)
 
 void vlc_cond_signal (vlc_cond_t *p_condvar)
 {
-    /* NOTE: This will cause a broadcast, that is wrong.
-     * This will also wake up the next waiting thread if no threads are yet
-     * waiting, which is also wrong. However both of these issues are allowed
-     * by the provision for spurious wakeups. Better have too many wakeups
-     * than too few (= deadlocks). */
-    SetEvent (p_condvar->handle);
+    if (!p_condvar->handle)
+        return;
+
+    /* This is suboptimal but works. */
+    vlc_cond_broadcast (p_condvar);
 }
 
 void vlc_cond_broadcast (vlc_cond_t *p_condvar)
 {
+    if (!p_condvar->handle)
+        return;
+
+    /* Wake all threads up (as the event HANDLE has manual reset) */
     SetEvent (p_condvar->handle);
 }
 
@@ -279,6 +282,12 @@ void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
 {
     DWORD result;
 
+    if (!p_condvar->handle)
+    {   /* FIXME FIXME FIXME */
+        msleep (50000);
+        return;
+    }
+
     do
     {
         vlc_testcancel ();
@@ -296,6 +305,12 @@ int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
 {
     DWORD result;
 
+    if (!p_condvar->handle)
+    {   /* FIXME FIXME FIXME */
+        msleep (50000);
+        return 0;
+    }
+
     do
     {
         vlc_testcancel ();