Bug 666446, Part 2/18 - Change nsRefreshDriver to accept imgIRequest objects to facilitate refresh driver-based animations. [r=roc]

layout/base/nsRefreshDriver.cpp

@@ -112,6 +112,7 @@ nsRefreshDriver::nsRefreshDriver(nsPresContext *aPresContext)
     mTimerIsPrecise(false),
     mLastTimerInterval(0)
 {
+  mRequests.Init();
 }
 
 nsRefreshDriver::~nsRefreshDriver()
@@ -183,6 +184,29 @@ nsRefreshDriver::RemoveRefreshObserver(nsARefreshObserver *aObserver,
   return array.RemoveElement(aObserver);
 }
 
+bool
+nsRefreshDriver::AddImageRequest(imgIRequest* aRequest)
+{
+  if (!mRequests.PutEntry(aRequest)) {
+    return false;
+  }
+
+  EnsureTimerStarted(false);
+
+  return true;
+}
+
+void
+nsRefreshDriver::RemoveImageRequest(imgIRequest* aRequest)
+{
+  mRequests.RemoveEntry(aRequest);
+}
+
+void nsRefreshDriver::ClearAllImageRequests()
+{
+  mRequests.Clear();
+}
+
 void
 nsRefreshDriver::EnsureTimerStarted(bool aAdjustingTimer)
 {
@@ -236,6 +260,7 @@ nsRefreshDriver::ObserverCount() const
   for (PRUint32 i = 0; i < NS_ARRAY_LENGTH(mObservers); ++i) {
     sum += mObservers[i].Length();
   }
+
   // Even while throttled, we need to process layout and style changes.  Style
   // changes can trigger transitions which fire events when they complete, and
   // layout changes can affect media queries on child documents, triggering
@@ -247,6 +272,12 @@ nsRefreshDriver::ObserverCount() const
   return sum;
 }
 
+PRUint32
+nsRefreshDriver::ImageRequestCount() const
+{
+  return mRequests.Count();
+}
+
 void
 nsRefreshDriver::UpdateMostRecentRefresh()
 {
@@ -301,7 +332,7 @@ nsRefreshDriver::Notify(nsITimer *aTimer)
   UpdateMostRecentRefresh();
 
   nsCOMPtr<nsIPresShell> presShell = mPresContext->GetPresShell();
-  if (!presShell || ObserverCount() == 0) {
+  if (!presShell || (ObserverCount() == 0 && ImageRequestCount() == 0)) {
     // Things are being destroyed, or we no longer have any observers.
     // We don't want to stop the timer when observers are initially
     // removed, because sometimes observers can be added and removed
@@ -330,6 +361,7 @@ nsRefreshDriver::Notify(nsITimer *aTimer)
         return NS_OK;
       }
     }
+
     if (i == 0) {
       // Don't just loop while we have things in mBeforePaintTargets,
       // the whole point is that event handlers should readd the
@@ -402,6 +434,17 @@ nsRefreshDriver::Notify(nsITimer *aTimer)
     }
   }
 
+  /*
+   * Perform notification to imgIRequests subscribed to listen
+   * for refresh events.
+   */
+
+  ImageRequestParameters parms = {mMostRecentRefresh};
+  if (mRequests.Count()) {
+    mRequests.EnumerateEntries(nsRefreshDriver::ImageRequestEnumerator, &parms);
+    EnsureTimerStarted(false);
+  }
+
   if (mThrottled ||
       (mTimerIsPrecise !=
        (GetRefreshTimerType() == nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP))) {
@@ -422,6 +465,24 @@ nsRefreshDriver::Notify(nsITimer *aTimer)
   return NS_OK;
 }
 
+PLDHashOperator
+nsRefreshDriver::ImageRequestEnumerator(nsISupportsHashKey* aEntry,
+                                        void* aUserArg)
+{
+  ImageRequestParameters* parms =
+    static_cast<ImageRequestParameters*> (aUserArg);
+  mozilla::TimeStamp mostRecentRefresh = parms->ts;
+  imgIRequest* req = static_cast<imgIRequest*>(aEntry->GetKey());
+  NS_ABORT_IF_FALSE(req, "Unable to retrieve the image request");
+  nsCOMPtr<imgIContainer> image;
+  req->GetImage(getter_AddRefs(image));
+  if (image) {
+    image->RequestRefresh(mostRecentRefresh);
+  }
+
+  return PL_DHASH_NEXT;
+}
+
 void
 nsRefreshDriver::Freeze()
 {
@@ -435,7 +496,7 @@ nsRefreshDriver::Thaw()
 {
   NS_ASSERTION(mFrozen, "Thaw called on an unfrozen refresh driver");
   mFrozen = false;
-  if (ObserverCount()) {
+  if (ObserverCount() || ImageRequestCount()) {
     // FIXME: This isn't quite right, since our EnsureTimerStarted call
     // updates our mMostRecentRefresh, but the DoRefresh call won't run
     // and notify our observers until we get back to the event loop.

layout/base/nsRefreshDriver.h

@@ -50,10 +50,13 @@
 #include "nsTObserverArray.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
+#include "nsTHashtable.h"
+#include "nsHashKeys.h"
 
 class nsPresContext;
 class nsIPresShell;
 class nsIDocument;
+class imgIRequest;
 
 /**
  * An abstract base class to be implemented by callers wanting to be
@@ -128,6 +131,24 @@ public:
   bool RemoveRefreshObserver(nsARefreshObserver *aObserver,
                                mozFlushType aFlushType);
 
+  /**
+   * Add/Remove imgIRequest versions of observers.
+   *
+   * These are used for hooking into the refresh driver for
+   * controlling animated images.
+   *
+   * @note The refresh driver owns a reference to these listeners.
+   *
+   * @note Technically, imgIRequest objects are not nsARefreshObservers, but
+   * for controlling animated image repaint events, we subscribe the
+   * imgIRequests to the nsRefreshDriver for notification of paint events.
+   *
+   * @returns whether the operation succeeded, or void in the case of removal.
+   */
+  bool AddImageRequest(imgIRequest* aRequest);
+  void RemoveImageRequest(imgIRequest* aRequest);
+  void ClearAllImageRequests();
+
   /**
    * Add / remove presshells that we should flush style and layout on
    */
@@ -218,10 +239,15 @@ public:
 
 private:
   typedef nsTObserverArray<nsARefreshObserver*> ObserverArray;
+  typedef nsTHashtable<nsISupportsHashKey> RequestTable;
 
   void EnsureTimerStarted(bool aAdjustingTimer);
   void StopTimer();
+
   PRUint32 ObserverCount() const;
+  PRUint32 ImageRequestCount() const;
+  static PLDHashOperator ImageRequestEnumerator(nsISupportsHashKey* aEntry,
+                                          void* aUserArg);
   void UpdateMostRecentRefresh();
   ObserverArray& ArrayFor(mozFlushType aFlushType);
   // Trigger a refresh immediately, if haven't been disconnected or frozen.
@@ -252,6 +278,8 @@ private:
 
   // separate arrays for each flush type we support
   ObserverArray mObservers[3];
+  RequestTable mRequests;
+
   nsAutoTArray<nsIPresShell*, 16> mStyleFlushObservers;
   nsAutoTArray<nsIPresShell*, 16> mLayoutFlushObservers;
   // nsTArray on purpose, because we want to be able to swap.
@@ -262,6 +290,11 @@ private:
   // This is the last interval we used for our timer.  May be 0 if we
   // haven't computed a timer interval yet.
   mutable PRInt32 mLastTimerInterval;
+
+  // Helper struct for processing image requests
+  struct ImageRequestParameters {
+      mozilla::TimeStamp ts;
+  };
 };
 
 #endif /* !defined(nsRefreshDriver_h_) */