[WIP] Web Animations API: Constructing an Animation from partial keyframes throws a JS exception

Source/core/animation/EffectInput.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 30 matching lines @@
 namespace WebCore {
 
 static bool checkDocumentAndRenderer(Element* element)
 {
     if (!element->inActiveDocument())
         return false;
     element->document().updateStyleIfNeeded();
     return element->renderer();
 }
 
-PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, const Vector<Dictionary>& keyframeDictionaryVector, bool unsafe)
+static bool hasMismatchedKeyframeProperty(Vector<RefPtr<MutableStylePropertySet> > propertySetVector)

[dstockwell, 2014/03/11 03:28:14]

Instead of doing the checks here, we might be able to add a method to
KeyframeEffectModel that just calls ensureKeyframeGroups and then checks that
none require composite: add.

eg. bool KeyframeEffectModel::isReplaceOnly()

+{
+    HashCountedSet<CSSPropertyID> counter;
+    for (size_t i = 0; i < propertySetVector.size(); ++i) {
+        for (size_t j = 0; j < propertySetVector[i]->propertyCount(); ++j) {
+            CSSPropertyID property = propertySetVector[i]->propertyAt(j).id();
+            counter.add(property);
+        }
+    }
+    for (HashCountedSet<CSSPropertyID>::iterator iterator = counter.begin(); iterator != counter.end(); ++iterator) {
+        if (iterator->value == 1)
+            return true;
+    }
+    return false;
+}
+
+PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, const Vector<Dictionary>& keyframeDictionaryVector,  ExceptionState& exceptionState, bool unsafe)
 {
     // FIXME: This test will not be neccessary once resolution of keyframe values occurs at
     // animation application time.
     if (!unsafe && !checkDocumentAndRenderer(element))
         return nullptr;
 
     // FIXME: Move this code into KeyframeEffectModel, it will be used by the IDL constructor for that class.
     KeyframeEffectModel::KeyframeVector keyframes;
     Vector<RefPtr<MutableStylePropertySet> > propertySetVector;
+    bool hasOffsets = false;
+    bool hasOffsetZero = false;
+    bool hasOffsetOne = false;
 
     for (size_t i = 0; i < keyframeDictionaryVector.size(); ++i) {
         RefPtr<MutableStylePropertySet> propertySet = MutableStylePropertySet::create();
         propertySetVector.append(propertySet);
 
         RefPtrWillBeRawPtr<Keyframe> keyframe = Keyframe::create();
         keyframes.append(keyframe);
 
         double offset;
-        if (keyframeDictionaryVector[i].get("offset", offset))
+        if (keyframeDictionaryVector[i].get("offset", offset)) {
             keyframe->setOffset(offset);
+            hasOffsets = true;
+            if (!offset)
+                hasOffsetZero = true;
+            if (offset == 1)
+                hasOffsetOne = true;
+        }
 
         String compositeString;
         keyframeDictionaryVector[i].get("composite", compositeString);
         if (compositeString == "add")
             keyframe->setComposite(AnimationEffect::CompositeAdd);
 
         String timingFunctionString;
         if (keyframeDictionaryVector[i].get("easing", timingFunctionString)) {
             RefPtrWillBeRawPtr<CSSValue> timingFunctionValue = BisonCSSParser::parseAnimationTimingFunctionValue(timingFunctionString);
             if (timingFunctionValue)
@@ skipping 14 matching lines @@
             // KeyframeEffectModel, store input keyframes and implement getFrames.
             if (id == CSSPropertyInvalid || !CSSAnimations::isAnimatableProperty(id))
                 continue;
 
             String value;
             keyframeDictionaryVector[i].get(property, value);
             propertySet->setProperty(id, value);
         }
     }
 
+    // FIXME: Web Animations can't yet handle keyframe sets where a property appears in only one keyframe (called "partial keyframes").
+    // This check can be removed once support for such input is added.
+    if (hasMismatchedKeyframeProperty(propertySetVector))
+        exceptionState.throwDOMException(NotSupportedError, "Keyframe effect contains properties that appear in only one keyframe.");
+    // FIXME: Web Animations can't yet handle keyframe sets which specify offsets and don't specify keyframes at offset: 0 and offset: 1.
+    // These checks can be removed once support for such input is added.
+    if (hasOffsets && !hasOffsetZero)
+        exceptionState.throwDOMException(NotSupportedError, "Keyframes specify offsets, but keyframe with offset: 0 is missing.");
+    if (hasOffsets && !hasOffsetOne)
+        exceptionState.throwDOMException(NotSupportedError, "Keyframes specify offsets, but keyframe with offset: 1 is missing.");
+
     // FIXME: Replace this with code that just parses, when that code is available.
     return StyleResolver::createKeyframeEffectModel(*element, propertySetVector, keyframes);
 }
 
 } // namespace WebCore