[wip] interpolable value refactor. NOT FOR LANDING.

Source/core/animation/Interpolation.h

+/*
+ * Copyright (C) 2014 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
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef Interpolation_h
+#define Interpolation_h
+
+#include "core/animation/InterpolableValue.h"
+#include "wtf/RefCounted.h"
+
+namespace WebCore {
+
+class StyleResolverState;
+
+class Interpolation : public RefCounted<Interpolation> {
+public:
+    static PassRefPtr<Interpolation> create(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end)
+    {
+        return adoptRef(new Interpolation(start, end));
+    }
+
+    void interpolate(int iteration, double fraction) const
+    {
+        if (m_cachedFraction != fraction || m_cachedIteration != iteration)
+        {
+            m_cachedValue = m_start->interpolate(*m_end, fraction);
+            m_cachedIteration = iteration;
+            m_cachedFraction = fraction;
+        }
+    }
+
+protected:
+    const OwnPtr<InterpolableValue> m_start;
+    const OwnPtr<InterpolableValue> m_end;
+
+    mutable double m_cachedFraction;
+    mutable int m_cachedIteration;
+    mutable OwnPtr<InterpolableValue> m_cachedValue;
+
+    Interpolation(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end)
+        : m_start(start)
+        , m_end(end)
+        , m_cachedFraction(0)
+        , m_cachedValue(m_start->clone())
+    { }
+};
+
+class StyleInterpolation : public Interpolation {
+public:
+    // 1) convert m_cachedValue into an X
+    // 2) shove X into StyleResolverState
+    // X can be:
+    // (1) a CSSValue (and applied via StyleBuilder::applyProperty)
+    // (2) an AnimatableValue (and applied via // AnimatedStyleBuilder::applyProperty)
+    // (3) a custom value that is inserted directly into the StyleResolverState.
+    virtual void apply(StyleResolverState& state) const = 0;
+
+    CSSPropertyID id() const { return m_id; }
+
+protected:
+    CSSPropertyID m_id;
+
+    StyleInterpolation(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end, CSSPropertyID id)
+        : Interpolation(start, end)
+        , m_id(id)
+    { }
+};
+
+class LegacyStyleInterpolation : public StyleInterpolation {
+public:
+    static PassRefPtr<LegacyStyleInterpolation> create(PassRefPtr<AnimatableValue> start, PassRefPtr<AnimatableValue> end, CSSPropertyID id)
+    {
+        return adoptRef(new LegacyStyleInterpolation(InterpolableAnimatableValue::create(start), InterpolableAnimatableValue::create(end), id));
+    }
+
+    virtual void apply(StyleResolverState& state) const;
+
+    AnimatableValue* currentValue() const {
+        InterpolableAnimatableValue *value = static_cast<InterpolableAnimatableValue *>(m_cachedValue.get());
+        return value->value();
+    }
+
+private:
+    LegacyStyleInterpolation(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end, CSSPropertyID id)
+        : StyleInterpolation(start, end, id)
+    { }
+};
+
+}
+#endif