Bug 512525 - Implement SVG Fragment Identifier parsing and animation hyperlinking - Part 1 infrastructure to support hyperlinking. r=dholbert

content/smil/nsSMILTimedElement.cpp

@@ -354,6 +354,23 @@ nsSMILTimedElement::GetStartTime() const
          : nsSMILTimeValue();
 }
 
+//----------------------------------------------------------------------
+// Hyperlinking support
+
+nsSMILTimeValue
+nsSMILTimedElement::GetHyperlinkTime() const
+{
+  nsSMILTimeValue hyperlinkTime; // Default ctor creates unresolved time
+
+  if (mElementState == STATE_ACTIVE) {
+    hyperlinkTime = mCurrentInterval->Begin()->Time();
+  } else if (!mBeginInstances.IsEmpty()) {
+    hyperlinkTime = mBeginInstances[0]->Time();
+  }
+
+  return hyperlinkTime;
+}
+
 //----------------------------------------------------------------------
 // nsSMILTimedElement
 
@@ -1492,7 +1509,8 @@ nsSMILTimedElement::FilterIntervals()
   // We can filter old intervals that:
   //
   // a) are not the previous interval; AND
-  // b) are not in the middle of a dependency chain
+  // b) are not in the middle of a dependency chain; AND
+  // c) are not the first interval
   //
   // Condition (a) is necessary since the previous interval is used for applying
   // fill effects and updating the current interval.
@@ -1502,6 +1520,15 @@ nsSMILTimedElement::FilterIntervals()
   // intervals. Such chains are used to establish priorities within the
   // animation sandwich.
   //
+  // Condition (c) is necessary to support hyperlinks that target animations
+  // since in some cases the defined behavior is to seek the document back to
+  // the first resolved begin time. Presumably the intention here is not
+  // actually to use the first resolved begin time, the
+  // _the_first_resolved_begin_time_that_produced_an_interval. That is,
+  // if we have begin="-5s; -3s; 1s; 3s" with a duration on 1s, we should seek
+  // to 1s. The spec doesn't say this but I'm pretty sure that is the intention.
+  // It seems negative times were simply not considered.
+  //
   // Although the above conditions allow us to safely filter intervals for most
   // scenarios they do not cover all cases and there will still be scenarios
   // that generate intervals indefinitely. In such a case we simply set
@@ -1514,7 +1541,8 @@ nsSMILTimedElement::FilterIntervals()
   for (PRUint32 i = 0; i < mOldIntervals.Length(); ++i)
   {
     nsSMILInterval* interval = mOldIntervals[i].get();
-    if (i + 1 < mOldIntervals.Length() /*skip previous interval*/ &&
+    if (i != 0 && /*skip first interval*/
+        i + 1 < mOldIntervals.Length() && /*skip previous interval*/
         (i < threshold || !interval->IsDependencyChainLink())) {
       interval->Unlink(true /*filtered, not deleted*/);
     } else {
@@ -1584,6 +1612,7 @@ nsSMILTimedElement::FilterInstanceTimes(InstanceTimeList& aList)
     // There are a few instance times we should keep though, notably:
     // - the current interval begin time,
     // - the previous interval end time (see note in RemoveInstanceTimes)
+    // - the first interval begin time (see note in FilterIntervals)
     nsTArray<const nsSMILInstanceTime *> timesToKeep;
     if (mCurrentInterval) {
       timesToKeep.AppendElement(mCurrentInterval->Begin());
@@ -1592,6 +1621,9 @@ nsSMILTimedElement::FilterInstanceTimes(InstanceTimeList& aList)
     if (prevInterval) {
       timesToKeep.AppendElement(prevInterval->End());
     }
+    if (!mOldIntervals.IsEmpty()) {
+      timesToKeep.AppendElement(mOldIntervals[0]->Begin());
+    }
     RemoveBelowThreshold removeBelowThreshold(threshold, timesToKeep);
     RemoveInstanceTimes(aList, removeBelowThreshold);
   }

content/smil/nsSMILTimedElement.h

@@ -139,10 +139,29 @@ public:
     return mSimpleDur;
   }
 
+  /**
+   * Methods for supporting hyperlinking
+   */
+
   /**
    * Internal SMIL methods
    */
 
+  /**
+   * Returns the time to seek the document to when this element is targetted by
+   * a hyperlink.
+   *
+   * The behavior is defined here:
+   *   http://www.w3.org/TR/smil-animation/#HyperlinkSemantics
+   *
+   * It is very similar to GetStartTime() with the exception that when the
+   * element is not active, the begin time of the *first* interval is returned.
+   *
+   * @return the time to seek the documen to in milliseconds or an unresolved
+   * time if there is no resolved interval.
+   */
+  nsSMILTimeValue GetHyperlinkTime() const;
+
   /**
    * Adds an instance time object this element's list of instance times.
    * These instance times are used when creating intervals.

content/svg/content/src/nsSVGAnimationElement.cpp

@@ -422,6 +422,34 @@ nsSVGAnimationElement::IsNodeOfType(PRUint32 aFlags) const
   return !(aFlags & ~(eCONTENT | eANIMATION));
 }
 
+//----------------------------------------------------------------------
+// SVG utility methods
+
+void
+nsSVGAnimationElement::ActivateByHyperlink()
+{
+  FlushAnimations();
+
+  // The behavior for when the target is an animation element is defined in
+  // SMIL Animation:
+  //   http://www.w3.org/TR/smil-animation/#HyperlinkSemantics
+  nsSMILTimeValue seekTime = mTimedElement.GetHyperlinkTime();
+  if (seekTime.IsDefinite()) {
+    nsSMILTimeContainer* timeContainer = GetTimeContainer();
+    if (timeContainer) {
+      timeContainer->SetCurrentTime(seekTime.GetMillis());
+      AnimationNeedsResample();
+      // As with nsSVGSVGElement::SetCurrentTime, we need to trigger
+      // a synchronous sample now.
+      FlushAnimations();
+    }
+    // else, silently fail. We mustn't be part of an SVG document fragment that
+    // is attached to the document tree so there's nothing we can do here
+  } else {
+    BeginElement();
+  }
+}
+
 //----------------------------------------------------------------------
 // Implementation helpers
 

content/svg/content/src/nsSVGAnimationElement.h

@@ -100,6 +100,9 @@ public:
   virtual nsSMILTimedElement& TimedElement();
   virtual nsSMILTimeContainer* GetTimeContainer();
 
+  // Utility methods for within SVG
+  void ActivateByHyperlink();
+
 protected:
   // nsSVGElement overrides
   bool IsEventName(nsIAtom* aName);