Web Animations API: Sort keyframes by offset

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 20 matching lines @@
 #include "config.h"
 #include "core/animation/EffectInput.h"
 
 #include "bindings/v8/Dictionary.h"
 #include "core/animation/AnimationHelpers.h"
 #include "core/animation/KeyframeEffectModel.h"
 #include "core/animation/StringKeyframe.h"
 #include "core/css/parser/BisonCSSParser.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/Element.h"
+#include "wtf/NonCopyingSort.h"
 
 namespace WebCore {
 
 // FIXME: Remove this once we've removed the dependency on Element.
 static bool checkDocumentAndRenderer(Element* element)
 {
     if (!element || !element->inActiveDocument())
         return false;
     element->document().updateRenderTreeIfNeeded();
     return element->renderer();
 }
 
 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;
 
     StyleSheetContents* styleSheetContents = element->document().elementSheet().contents();
     StringKeyframeVector keyframes;
+    bool everyFrameHasOffset = true;
+    bool looselySortedByOffset = true;
+    double lastOffset = -std::numeric_limits<double>::infinity();
 
     for (size_t i = 0; i < keyframeDictionaryVector.size(); ++i) {
         RefPtrWillBeRawPtr<StringKeyframe> keyframe = StringKeyframe::create();
+
+        bool frameHasOffset = false;
+        double offset;
+        if (keyframeDictionaryVector[i].get("offset", offset)) {
+            // Keyframes with offsets outside the range [0.0, 1.0] are ignored.
+            if (std::isnan(offset) || offset < 0 || offset > 1)
+                continue;
+
+            frameHasOffset = true;
+            // The JS value null gets converted to 0 so we need to check whether the original value is null.
+            if (offset == 0) {
+                ScriptValue scriptValue;
+                if (keyframeDictionaryVector[i].get("offset", scriptValue) && scriptValue.isNull())
+                    frameHasOffset = false;
+            }
+            if (frameHasOffset) {
+                keyframe->setOffset(offset);
+                if (offset < lastOffset)
+                    looselySortedByOffset = false;
+                lastOffset = offset;
+            }
+        }
+        everyFrameHasOffset = everyFrameHasOffset && frameHasOffset;
+
         keyframes.append(keyframe);
 
-        double offset;
-        if (keyframeDictionaryVector[i].get("offset", offset))
-            keyframe->setOffset(offset);
-
         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)
                 keyframe->setEasing(CSSToStyleMap::animationTimingFunction(timingFunctionValue.get(), false));
         }
 
         Vector<String> keyframeProperties;
         keyframeDictionaryVector[i].getOwnPropertyNames(keyframeProperties);
         for (size_t j = 0; j < keyframeProperties.size(); ++j) {
             String property = keyframeProperties[j];
             CSSPropertyID id = camelCaseCSSPropertyNameToID(property);
             if (id == CSSPropertyInvalid)
                 continue;
             String value;
             keyframeDictionaryVector[i].get(property, value);
             keyframe->setPropertyValue(id, value, styleSheetContents);
         }
     }
 
+    if (!looselySortedByOffset) {
+        if (!everyFrameHasOffset) {
+            exceptionState.throwDOMException(InvalidModificationError, "Keyframes are not loosely sorted by offset.");
+            return nullptr;
+        }
+        nonCopyingSort(keyframes.begin(), keyframes.end(), Keyframe::compareOffsets);
+    }
+
     RefPtrWillBeRawPtr<StringKeyframeEffectModel> keyframeEffectModel = StringKeyframeEffectModel::create(keyframes);
     if (!keyframeEffectModel->isReplaceOnly()) {
         exceptionState.throwDOMException(NotSupportedError, "Partial keyframes are not supported.");
         return nullptr;
     }
     keyframeEffectModel->forceConversionsToAnimatableValues(element);
 
     return keyframeEffectModel;
 }
 
 } // namespace WebCore