[vlc-devel] [PATCH] win32: use the ThreadPoolTimer API to handle timers

[Steve Lhomme]

This is available since Windows 7 and is allowed in Winstore apps. So we only
maintain one code for all Windows versions.

It should handle timers with an absolute time better as they had to be turned
into relative times but the system sleep was delaying the timer. [1]

[1] https://docs.microsoft.com/en-us/windows/win32/api/threadpoollegacyapiset/nf-threadpoollegacyapiset-createtimerqueuetimer
"The time that the system spends in sleep or hibernation does not count toward
the expiration of the timer."
---
 src/Makefile.am   |  5 +++--
 src/win32/timer.c | 46 ++++++++++++++++++++++++----------------------
 2 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 9e088c1fd9e6..dc75776d7af7 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -406,11 +406,12 @@ libvlccore_la_SOURCES += \
 	win32/rand.c \
 	win32/specific.c \
 	win32/thread.c \
+	win32/timer.c \
 	win32/winsock.c
 if HAVE_WINSTORE
-libvlccore_la_SOURCES += posix/timer.c win32/dirs-uap.c
+libvlccore_la_SOURCES += win32/dirs-uap.c
 else
-libvlccore_la_SOURCES += win32/timer.c win32/dirs.c
+libvlccore_la_SOURCES += win32/dirs.c
 endif
 endif
 
diff --git a/src/win32/timer.c b/src/win32/timer.c
index 4fe3d2b067cb..4a2d68f996fb 100644
--- a/src/win32/timer.c
+++ b/src/win32/timer.c
@@ -29,16 +29,16 @@
 
 struct vlc_timer
 {
-    HANDLE handle;
+    PTP_TIMER ptimer;
     void (*func) (void *);
     void *data;
 };
 
-static void CALLBACK vlc_timer_do (void *val, BOOLEAN timeout)
+static void CALLBACK vlc_timer_do(PTP_CALLBACK_INSTANCE instance, void *val, PTP_TIMER ptimer)
 {
+    (void) instance; (void) ptimer;
     struct vlc_timer *timer = val;
 
-    assert (timeout);
     timer->func (timer->data);
 }
 
@@ -50,50 +50,52 @@ int vlc_timer_create (vlc_timer_t *id, void (*func) (void *), void *data)
         return ENOMEM;
     timer->func = func;
     timer->data = data;
-    timer->handle = INVALID_HANDLE_VALUE;
+    timer->ptimer = CreateThreadpoolTimer(vlc_timer_do, timer, NULL);
+    if (unlikely(timer->ptimer == NULL))
+    {
+        free(timer);
+        return EFAULT;
+    }
     *id = timer;
     return 0;
 }
 
 void vlc_timer_destroy (vlc_timer_t timer)
 {
-    if (timer->handle != INVALID_HANDLE_VALUE)
-        DeleteTimerQueueTimer (NULL, timer->handle, INVALID_HANDLE_VALUE);
+    SetThreadpoolTimer(timer->ptimer, NULL, 0, 0);
+    WaitForThreadpoolTimerCallbacks(timer->ptimer, TRUE);
+    CloseThreadpoolTimer(timer->ptimer);
     free (timer);
 }
 
 void vlc_timer_schedule (vlc_timer_t timer, bool absolute,
                          vlc_tick_t value, vlc_tick_t interval)
 {
-    if (timer->handle != INVALID_HANDLE_VALUE)
-    {
-        DeleteTimerQueueTimer (NULL, timer->handle, INVALID_HANDLE_VALUE);
-        timer->handle = INVALID_HANDLE_VALUE;
-    }
+    SetThreadpoolTimer(timer->ptimer, NULL, 0, 0);
+    WaitForThreadpoolTimerCallbacks(timer->ptimer, TRUE);
     if (value == VLC_TIMER_DISARM)
         return; /* Disarm */
 
+    ULARGE_INTEGER s;
     if (absolute)
-    {
-        value -= vlc_tick_now ();
-        if (value < 0)
-            value = 0;
-    }
+        s.QuadPart = MSFTIME_FROM_VLC_TICK(value);
+    else
+        s.QuadPart = -MSFTIME_FROM_VLC_TICK(value);
+    FILETIME ts;
+    ts.dwLowDateTime  = s.LowPart;
+    ts.dwHighDateTime = s.HighPart;
 
-    DWORD val    = MS_FROM_VLC_TICK(value);
     DWORD interv = MS_FROM_VLC_TICK(interval);
-    if (val == 0 && value != 0)
-        val = 1; /* rounding error */
     if (interv == 0 && interval != 0)
         interv = 1; /* rounding error */
 
-    if (!CreateTimerQueueTimer(&timer->handle, NULL, vlc_timer_do, timer,
-                               val, interv, WT_EXECUTEDEFAULT))
-        abort ();
+    WaitForThreadpoolTimerCallbacks(timer->ptimer, FALSE);
+    SetThreadpoolTimer(timer->ptimer, &ts, interv, 0 );
 }
 
 unsigned vlc_timer_getoverrun (vlc_timer_t timer)
 {
+    // TODO return the amount of missed timers if any
     (void)timer;
     return 0;
 }
-- 
2.26.2