Move static methods out of CSSLengthInterpolationType to LengthInterpolationFunctions

third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp

Index: third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
diff --git a/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp b/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..dcdb9d7cfde90ee5cf0c9bac488851e65f7b7e54
--- /dev/null
+++ b/third_party/WebKit/Source/core/animation/LengthInterpolationFunctions.cpp
@@ -0,0 +1,165 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/animation/LengthInterpolationFunctions.h"
+
+#include "core/css/CSSPrimitiveValue.h"
+#include "core/css/CSSToLengthConversionData.h"
+#include "platform/CalculationValue.h"
+
+namespace blink {
+
+// This class is implemented as a singleton whose instance represents the presence of percentages being used in a Length value
+// while nullptr represents the absence of any percentages.
+class CSSLengthNonInterpolableValue : public NonInterpolableValue {
+public:
+    ~CSSLengthNonInterpolableValue() final { NOTREACHED(); }
+    static PassRefPtr<CSSLengthNonInterpolableValue> create(bool hasPercentage)
+    {
+        DEFINE_STATIC_REF(CSSLengthNonInterpolableValue, singleton, adoptRef(new CSSLengthNonInterpolableValue()));
+        DCHECK(singleton);
+        return hasPercentage ? singleton : nullptr;
+    }
+    static PassRefPtr<CSSLengthNonInterpolableValue> merge(const NonInterpolableValue* a, const NonInterpolableValue* b)
+    {
+        return create(hasPercentage(a) || hasPercentage(b));
+    }
+    static bool hasPercentage(const NonInterpolableValue* nonInterpolableValue)
+    {
+        DCHECK(!nonInterpolableValue || nonInterpolableValue->getType() == CSSLengthNonInterpolableValue::staticType);
+        return static_cast<bool>(nonInterpolableValue);
+    }
+
+    DECLARE_NON_INTERPOLABLE_VALUE_TYPE();
+
+private:
+    CSSLengthNonInterpolableValue() { }
+};
+
+DEFINE_NON_INTERPOLABLE_VALUE_TYPE(CSSLengthNonInterpolableValue);
+DEFINE_NON_INTERPOLABLE_VALUE_TYPE_CASTS(CSSLengthNonInterpolableValue);
+
+std::unique_ptr<InterpolableValue> LengthInterpolationFunctions::createInterpolablePixels(double pixels)
+{
+    std::unique_ptr<InterpolableList> interpolableList = createNeutralInterpolableValue();
+    interpolableList->set(CSSPrimitiveValue::UnitTypePixels, InterpolableNumber::create(pixels));
+    return std::move(interpolableList);
+}
+
+InterpolationValue LengthInterpolationFunctions::createInterpolablePercent(double percent)
+{
+    std::unique_ptr<InterpolableList> interpolableList = createNeutralInterpolableValue();
+    interpolableList->set(CSSPrimitiveValue::UnitTypePercentage, InterpolableNumber::create(percent));
+    return InterpolationValue(std::move(interpolableList), CSSLengthNonInterpolableValue::create(true));
+}
+
+std::unique_ptr<InterpolableList> LengthInterpolationFunctions::createNeutralInterpolableValue()
+{
+    const size_t length = CSSPrimitiveValue::LengthUnitTypeCount;
+    std::unique_ptr<InterpolableList> values = InterpolableList::create(length);
+    for (size_t i = 0; i < length; i++)
+        values->set(i, InterpolableNumber::create(0));
+    return values;
+}
+
+InterpolationValue LengthInterpolationFunctions::maybeConvertCSSValue(const CSSValue& value)
+{
+    if (!value.isPrimitiveValue())
+        return nullptr;
+
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
+    if (!primitiveValue.isLength() && !primitiveValue.isPercentage() && !primitiveValue.isCalculatedPercentageWithLength())
+        return nullptr;
+
+    CSSLengthArray lengthArray;
+    primitiveValue.accumulateLengthArray(lengthArray);
+
+    std::unique_ptr<InterpolableList> values = InterpolableList::create(CSSPrimitiveValue::LengthUnitTypeCount);
+    for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++)
+        values->set(i, InterpolableNumber::create(lengthArray.values[i]));
+
+    bool hasPercentage = lengthArray.typeFlags.get(CSSPrimitiveValue::UnitTypePercentage);
+    return InterpolationValue(std::move(values), CSSLengthNonInterpolableValue::create(hasPercentage));
+}
+
+InterpolationValue LengthInterpolationFunctions::maybeConvertLength(const Length& length, float zoom)
+{
+    if (!length.isSpecified())
+        return nullptr;
+
+    PixelsAndPercent pixelsAndPercent = length.getPixelsAndPercent();
+    std::unique_ptr<InterpolableList> values = createNeutralInterpolableValue();
+    values->set(CSSPrimitiveValue::UnitTypePixels, InterpolableNumber::create(pixelsAndPercent.pixels / zoom));
+    values->set(CSSPrimitiveValue::UnitTypePercentage, InterpolableNumber::create(pixelsAndPercent.percent));
+
+    return InterpolationValue(std::move(values), CSSLengthNonInterpolableValue::create(length.hasPercent()));
+}
+
+PairwiseInterpolationValue LengthInterpolationFunctions::mergeSingles(InterpolationValue&& start, InterpolationValue&& end)
+{
+    return PairwiseInterpolationValue(
+        std::move(start.interpolableValue),
+        std::move(end.interpolableValue),
+        CSSLengthNonInterpolableValue::merge(start.nonInterpolableValue.get(), end.nonInterpolableValue.get()));
+}
+
+bool LengthInterpolationFunctions::nonInterpolableValuesAreCompatible(const NonInterpolableValue*, const NonInterpolableValue*)
+{
+    return true;

[suzyh_UTC10 (ex-contributor), 2016/08/29 07:12:31]

Looks like some further refactoring is needed as this no longer makes sense.

IIUC, "nonInterpolableValuesAreCompatible" is defined/used for ShadowNonInt'Val
and CSSLengthNonInt'Val and then the ListInterpolationFunctions. Either this
needs to be a function defined on NonInterpolableValue, inherited and overridden
only when needed; or these three usages need to be pulled out to yet another
separate library.

[alancutter (OOO until 2018), 2016/09/05 07:40:22]

Added type checks as discussed in https://codereview.chromium.org/2314443002.

+}
+
+void LengthInterpolationFunctions::composite(
+    std::unique_ptr<InterpolableValue>& underlyingInterpolableValue,
+    RefPtr<NonInterpolableValue>& underlyingNonInterpolableValue,
+    double underlyingFraction,
+    const InterpolableValue& interpolableValue,
+    const NonInterpolableValue* nonInterpolableValue)
+{
+    underlyingInterpolableValue->scaleAndAdd(underlyingFraction, interpolableValue);
+    underlyingNonInterpolableValue = CSSLengthNonInterpolableValue::merge(underlyingNonInterpolableValue.get(), nonInterpolableValue);
+}
+
+void LengthInterpolationFunctions::subtractFromOneHundredPercent(InterpolationValue& result)
+{
+    InterpolableList& list = toInterpolableList(*result.interpolableValue);
+    for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
+        double value = -toInterpolableNumber(*list.get(i)).value();
+        if (i == CSSPrimitiveValue::UnitTypePercentage)
+            value += 100;
+        toInterpolableNumber(*list.getMutable(i)).set(value);
+    }
+    result.nonInterpolableValue = CSSLengthNonInterpolableValue::create(true);
+}
+
+static double clampToRange(double x, ValueRange range)
+{
+    return (range == ValueRangeNonNegative && x < 0) ? 0 : x;
+}
+
+Length LengthInterpolationFunctions::createLength(const InterpolableValue& interpolableValue, const NonInterpolableValue* nonInterpolableValue, const CSSToLengthConversionData& conversionData, ValueRange range)
+{
+    const InterpolableList& interpolableList = toInterpolableList(interpolableValue);
+    bool hasPercentage = CSSLengthNonInterpolableValue::hasPercentage(nonInterpolableValue);

[suzyh_UTC10 (ex-contributor), 2016/08/29 07:12:31]

Why is hasPercentage a static function instead
nonInterpolableValue.hasPercentage()?

[alancutter (OOO until 2018), 2016/09/05 07:40:22]

It is false if nonInterpolableValue is nullptr. Calling methods on null pointers
is undefined behaviour (it'd probably work fine but wouldn't be healthy code).

+    double pixels = 0;
+    double percentage = 0;
+    for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
+        double value = toInterpolableNumber(*interpolableList.get(i)).value();
+        if (i == CSSPrimitiveValue::UnitTypePercentage) {
+            percentage = value;
+        } else {
+            CSSPrimitiveValue::UnitType type = CSSPrimitiveValue::lengthUnitTypeToUnitType(static_cast<CSSPrimitiveValue::LengthUnitType>(i));
+            pixels += conversionData.zoomedComputedPixels(value, type);
+        }
+    }
+
+    if (percentage != 0)
+        hasPercentage = true;
+    if (pixels != 0 && hasPercentage)
+        return Length(CalculationValue::create(PixelsAndPercent(pixels, percentage), range));
+    if (hasPercentage)
+        return Length(clampToRange(percentage, range), Percent);
+    return Length(CSSPrimitiveValue::clampToCSSLengthRange(clampToRange(pixels, range)), Fixed);
+}
+
+} // namespace blink