Improvements to TimedEventQueue.

Events are now cancelled given their "unique" event_id instead of the event pointer
itself (which may be reallocated in place if we're unlucky). Also the ability to
cancel multiple events matching a predicate has been added.

1 files changed, 30 insertions, 6 deletions

diff --git a/media/libstagefright/include/TimedEventQueue.h b/media/libstagefright/include/TimedEventQueue.h
index a264421..21eade3 100644
--- a/media/libstagefright/include/TimedEventQueue.h
+++ b/media/libstagefright/include/TimedEventQueue.h
@@ -28,16 +28,31 @@ namespace android {
 
 struct TimedEventQueue {
 
+    typedef int32_t event_id;
+
     struct Event : public RefBase {
-        Event() {}
+        Event()
+            : mEventID(0) {
+        }
+
         virtual ~Event() {}
 
+        event_id eventID() {
+            return mEventID;
+        }
+
     protected:
         virtual void fire(TimedEventQueue *queue, int64_t now_us) = 0;
 
     private:
         friend class TimedEventQueue;
 
+        event_id mEventID;
+
+        void setEventID(event_id id) {
+            mEventID = id;
+        }
+
         Event(const Event &);
         Event &operator=(const Event &);
     };
@@ -55,21 +70,29 @@ struct TimedEventQueue {
 
     // Posts an event to the front of the queue (after all events that
     // have previously been posted to the front but before timed events).
-    void postEvent(const sp<Event> &event);
+    event_id postEvent(const sp<Event> &event);
 
-    void postEventToBack(const sp<Event> &event);
+    event_id postEventToBack(const sp<Event> &event);
 
     // It is an error to post an event with a negative delay.
-    void postEventWithDelay(const sp<Event> &event, int64_t delay_us);
+    event_id postEventWithDelay(const sp<Event> &event, int64_t delay_us);
 
     // If the event is to be posted at a time that has already passed,
     // it will fire as soon as possible.
-    void postTimedEvent(const sp<Event> &event, int64_t realtime_us);
+    event_id postTimedEvent(const sp<Event> &event, int64_t realtime_us);
 
     // Returns true iff event is currently in the queue and has been
     // successfully cancelled. In this case the event will have been
     // removed from the queue and won't fire.
-    bool cancelEvent(const sp<Event> &event);
+    bool cancelEvent(event_id id);
+
+    // Cancel any pending event that satisfies the predicate.
+    // If stopAfterFirstMatch is true, only cancels the first event
+    // satisfying the predicate (if any).
+    void cancelEvents(
+            bool (*predicate)(void *cookie, const sp<Event> &event),
+            void *cookie,
+            bool stopAfterFirstMatch = false);
 
     static int64_t getRealTimeUs();
 
@@ -90,6 +113,7 @@ private:
     Mutex mLock;
     Condition mQueueNotEmptyCondition;
     Condition mQueueHeadChangedCondition;
+    event_id mNextEventID;
 
     bool mRunning;
     bool mStopped;