Parsing CSS properties for scroll snap points

Source/core/css/resolver/StyleBuilderConverter.cpp

Index: Source/core/css/resolver/StyleBuilderConverter.cpp
diff --git a/Source/core/css/resolver/StyleBuilderConverter.cpp b/Source/core/css/resolver/StyleBuilderConverter.cpp
index 75b3a6c10977c0ee2f40c4b100cec5a181b02f35..bbf6b7f57fc376fd85ee333ac4f25dbf936ce633 100644
--- a/Source/core/css/resolver/StyleBuilderConverter.cpp
+++ b/Source/core/css/resolver/StyleBuilderConverter.cpp
@@ -59,6 +59,31 @@ static GridLength convertGridTrackBreadth(const StyleResolverState& state, CSSPr
     return StyleBuilderConverter::convertLengthOrAuto(state, primitiveValue);
 }
 
+template <CSSValueID cssValueFor0, CSSValueID cssValueFor100>
+static Length convertPositionLength(StyleResolverState& state, CSSPrimitiveValue* primitiveValue)
+{
+    if (Pair* pair = primitiveValue->getPairValue()) {
+        Length length = StyleBuilderConverter::convertLength(state, pair->second());
+        if (pair->first()->getValueID() == cssValueFor0)
+            return length;
+        ASSERT(pair->first()->getValueID() == cssValueFor100);
+        return length.subtractFromOneHundredPercent();
+    }
+
+    return StyleBuilderConverter::convertLength(state, primitiveValue);
+}
+
+static LengthSize convertSnapCoordinatePair(StyleResolverState& state, CSSValue* value)

[Timothy Loh, 2015/05/28 07:09:27]

I don't think anyone on Blink feels strongly about having static functions in
anonymous namespaces, I'd just have this next to the other snap-points
functions. Although if this is identical to convertObjectPosition, maybe we
should just rename that one to convertPosition and call it?

[majidvp, 2015/06/01 20:06:37]

Used convertPosition for both.

+{
+    CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
+    Pair* pair = primitiveValue->getPairValue();
+    return LengthSize(
+        convertPositionLength<CSSValueLeft, CSSValueRight>(state, pair->first()),
+        convertPositionLength<CSSValueTop, CSSValueBottom>(state, pair->second())
+    );
+}
+
+
 } // namespace
 
 PassRefPtr<StyleReflection> StyleBuilderConverter::convertBoxReflect(StyleResolverState& state, CSSValue* value)
@@ -635,20 +660,6 @@ float StyleBuilderConverter::convertNumberOrPercentage(StyleResolverState& state
     return primitiveValue->getFloatValue() / 100.0f;
 }
 
-template <CSSValueID cssValueFor0, CSSValueID cssValueFor100>
-static Length convertPositionLength(StyleResolverState& state, CSSPrimitiveValue* primitiveValue)
-{
-    if (Pair* pair = primitiveValue->getPairValue()) {
-        Length length = StyleBuilderConverter::convertLength(state, pair->second());
-        if (pair->first()->getValueID() == cssValueFor0)
-            return length;
-        ASSERT(pair->first()->getValueID() == cssValueFor100);
-        return length.subtractFromOneHundredPercent();
-    }
-
-    return StyleBuilderConverter::convertLength(state, primitiveValue);
-}
-
 LengthPoint StyleBuilderConverter::convertObjectPosition(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
@@ -901,4 +912,46 @@ TransformOrigin StyleBuilderConverter::convertTransformOrigin(StyleResolverState
     );
 }
 
+ScrollSnapPoints StyleBuilderConverter::convertSnapPoints(StyleResolverState& state, CSSValue* value)
+{
+    // Handles: none | repeat(<length>)
+    ScrollSnapPoints points;
+    points.hasRepeat = false;
+
+    if (!value->isFunctionValue()) {
+        return points;
+    }

[Timothy Loh, 2015/05/28 07:09:27]

Nit: No need for braces on single-line ifs

[majidvp, 2015/06/01 20:06:37]

Done.

+
+    if (CSSFunctionValue* repeatFunction = toCSSFunctionValue(value)) {

[Timothy Loh, 2015/05/28 07:09:27]

I don't think the condition is ever false here?

[majidvp, 2015/06/01 20:06:37]

Done.

+        ASSERT_WITH_SECURITY_IMPLICATION(repeatFunction->length() == 1);
+        points.repeatOffset = convertLength(state, toCSSPrimitiveValue(repeatFunction->item(0)));
+        points.hasRepeat = true;
+    }
+
+    return points;
+}
+
+Vector<LengthSize> StyleBuilderConverter::convertSnapCoordinates(StyleResolverState& state, CSSValue* value)
+{
+    // Handles: none | <position>#
+    Vector<LengthSize> coordinates;
+
+    if (!value->isValueList())
+        return coordinates;
+
+    CSSValueList* valueList = toCSSValueList(value);
+    coordinates.reserveInitialCapacity(valueList->length());
+    for (auto& snapCoordinate : *valueList) {
+        coordinates.uncheckedAppend(convertSnapCoordinatePair(state, snapCoordinate.get()));
+    }
+
+    return coordinates;
+}
+
+LengthSize StyleBuilderConverter::convertSnapDestination(StyleResolverState& state, CSSValue* value)
+{
+    return convertSnapCoordinatePair(state, value);
+}
+
+
 } // namespace blink