Parsing CSS properties for scroll snap points

Source/core/css/parser/CSSPropertyParser.cpp

Index: Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/Source/core/css/parser/CSSPropertyParser.cpp b/Source/core/css/parser/CSSPropertyParser.cpp
index a7170fdd2247855c091cedce0ce9daf81274f9ac..058f381eea74c870768dd74c1df56854e3c96940 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -727,7 +727,7 @@ bool CSSPropertyParser::parseValue(CSSPropertyID unresolvedProperty, bool import
         return result;
     }
     case CSSPropertyObjectPosition:
-        parsedValue = parseObjectPosition();
+        parsedValue = parsePosition();
         break;
     case CSSPropertyListStyleImage:     // <uri> | none | inherit
     case CSSPropertyBorderImageSource:
@@ -1495,6 +1495,17 @@ bool CSSPropertyParser::parseValue(CSSPropertyID unresolvedProperty, bool import
         validPrimitive = false;
         break;
 
+    case CSSPropertyScrollSnapPointsX:
+    case CSSPropertyScrollSnapPointsY:
+        parsedValue = parseScrollSnapPoints();
+        break;
+    case CSSPropertyScrollSnapCoordinate:
+        parsedValue = parseScrollSnapCoordinate();
+        break;
+    case CSSPropertyScrollSnapDestination:
+        parsedValue = parsePosition();
+        break;
+
     default:
         return parseSVGValue(propId, important);
     }
@@ -2008,6 +2019,44 @@ bool CSSPropertyParser::parse4Values(CSSPropertyID propId, const CSSPropertyID *
     return true;
 }
 
+PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseScrollSnapPoints()
+{
+    CSSParserValue* value = m_valueList->current();
+
+    if (value->id == CSSValueNone) {
+        m_valueList->next();
+        return cssValuePool().createIdentifierValue(CSSValueNone);
+    }
+
+    if (value->unit == CSSParserValue::Function && value->function->id == CSSValueRepeat) {
+        // The spec defines the following grammar: repeat( <length>)
+        CSSParserValueList* arguments = value->function->args.get();
+        if (!arguments || arguments->size() != 1)
+            return nullptr;
+
+        CSSParserValue* repeatValue = arguments->valueAt(0);
+        if (!validUnit(repeatValue, FNonNeg | FLength | FPercent))
+            return nullptr;
+
+        RefPtrWillBeRawPtr<CSSFunctionValue> result = CSSFunctionValue::create(CSSValueRepeat);
+        result->append(parseValidPrimitive(repeatValue->id, repeatValue));
+        m_valueList->next();
+        return result.release();
+    }
+
+    return nullptr;
+}
+
+PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseScrollSnapCoordinate()
+{
+    if (m_valueList->current()->id == CSSValueNone) {
+        m_valueList->next();
+        return cssValuePool().createIdentifierValue(CSSValueNone);
+    }
+
+    return parsePositionList(m_valueList);
+}
+
 PassRefPtrWillBeRawPtr<CSSPrimitiveValue> CSSPropertyParser::parsePage()
 {
     CSSParserValue* value = m_valueList->current();
@@ -5554,7 +5603,7 @@ bool CSSPropertyParser::parseFlex(CSSParserValueList* args, bool important)
     return true;
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseObjectPosition()
+PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parsePosition()
 {
     RefPtrWillBeRawPtr<CSSValue> xValue = nullptr;
     RefPtrWillBeRawPtr<CSSValue> yValue = nullptr;
@@ -5564,6 +5613,27 @@ PassRefPtrWillBeRawPtr<CSSValue> CSSPropertyParser::parseObjectPosition()
     return createPrimitiveValuePair(toCSSPrimitiveValue(xValue.get()), toCSSPrimitiveValue(yValue.get()), Pair::KeepIdenticalValues);
 }
 
+// Parses a list of comma separated positions. i.e., <position>#
+PassRefPtrWillBeRawPtr<CSSValueList> CSSPropertyParser::parsePositionList(CSSParserValueList* args)
+{
+    RefPtrWillBeRawPtr<CSSValueList> positions = CSSValueList::createCommaSeparated();
+    for (CSSParserValue* argument = args->current(); argument; argument = args->next()) {

[Timothy Loh, 2015/06/04 03:58:26]

I think this won't do exactly what you want (I think it'll allow "10px,",
"10px/", "10px banana", and so on). I think you'll want a loop like

    while (true) {
        RefPtrWillBeRawPtr<CSSValue> position = parsePosition();
        if (!position)
            return nullptr;
        list->append(position.release());
        if (!m_valueList->current())
            break;
        if (!consumeComma(m_valueList) || !m_valueList->current())
            return nullptr;
    }

[majidvp, 2015/06/04 22:41:40]

Done.

+        RefPtrWillBeRawPtr<CSSValue> xValue = nullptr;
+        RefPtrWillBeRawPtr<CSSValue> yValue = nullptr;
+        // parseFillPosition below should consume arguments until it reaches
+        // a comma or end of the list
+        parseFillPosition(args, xValue, yValue);
+
+        if (!xValue || !yValue)
+            return nullptr;
+
+        RefPtrWillBeRawPtr<CSSValue> position = createPrimitiveValuePair(toCSSPrimitiveValue(xValue.get()), toCSSPrimitiveValue(yValue.get()), Pair::KeepIdenticalValues);
+        positions->append(position);
+    }
+
+    return positions.release();
+}
+
 class BorderImageParseContext {
     STACK_ALLOCATED();
 public:
@@ -7155,6 +7225,7 @@ PassRefPtrWillBeRawPtr<CSSValueList> CSSPropertyParser::parseFilter()
 
     return list.release();
 }
+
 PassRefPtrWillBeRawPtr<CSSValueList> CSSPropertyParser::parseTransformOrigin()
 {
     CSSParserValue* value = m_valueList->current();