[WIP] CSS Motion Path: offset shorthand ready for position and anchor

third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
index db811aff923b963f1ce21b4345e7134d9deb362e..7b68f2946a358bc98ec7d11c6d5e9cb855e07827 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
@@ -1316,6 +1316,55 @@ bool CSSPropertyParser::consumeAnimationShorthand(const StylePropertyShorthand&
     return m_range.atEnd();
 }
 
+bool CSSPropertyParser::consumeOffsetShorthand(bool important)
+{
+    const CSSValue* offsetPosition = parseSingleValue(CSSPropertyOffsetPosition, CSSPropertyOffset);

[Timothy Loh, 2016/09/27 08:17:48]

For all of these we should prefer just calling the property consume functions
(e.g. consumeOffsetPosition) directly.

[Eric Willigers, 2016/09/29 03:53:19]

Done.

[Eric Willigers, 2016/09/29 03:53:19]

Done.

+    const CSSValue* offsetPath = parseSingleValue(CSSPropertyOffsetPath, CSSPropertyOffset);
+
+    if (!offsetPath && (!offsetPosition || !offsetPosition->isValuePair()))

[Timothy Loh, 2016/09/27 08:17:48]

What's the offsetPosition->isValuePair() check for?

[Timothy Loh, 2016/09/27 08:20:47]

Actually, shouldn't we always fail if offsetPath isn't set? It's non-optional in
the grammar you've linked to

<offset-position>? [ <offset-path> [ <offset-rotation> || <offset-distance> ] [
/ <offset-anchor> ]? ]

[Eric Willigers, 2016/09/29 03:53:19]

Checking that we don't have 'auto'.

The offset shorthand may simply contain a position.
https://logs.csswg.org/irc.w3.org/css/2016-09-20/#e724174


This CL uses the following grammar:
https://github.com/w3c/fxtf-drafts/pull/52/files
which also appears at the bottom of
https://github.com/w3c/fxtf-drafts/issues/42

+        return false;
+
+    const CSSValue* offsetRotation = parseSingleValue(CSSPropertyOffsetRotation, CSSPropertyOffset);
+    const CSSValue* offsetDistance = nullptr;
+    if (offsetPath) {
+        offsetDistance = parseSingleValue(CSSPropertyOffsetDistance, CSSPropertyOffset);
+        if (offsetDistance && !offsetRotation)
+            offsetRotation = parseSingleValue(CSSPropertyOffsetRotation, CSSPropertyOffset);
+    }
+    const CSSValue* offsetAnchor = nullptr;
+    if (consumeSlashIncludingWhitespace(m_range)) {

[Timothy Loh, 2016/09/27 08:17:48]

This code incorrectly allows <offset-position> / <offset-anchor>

[Eric Willigers, 2016/09/29 03:53:19]

Intended.

+        offsetAnchor = parseSingleValue(CSSPropertyOffsetAnchor, CSSPropertyOffset);
+        if (!offsetAnchor)
+            return false;
+    }
+
+    if (RuntimeEnabledFeatures::cssOffsetPositionAnchorEnabled()) {
+        addProperty(CSSPropertyOffsetPosition, CSSPropertyOffset, offsetPosition ? *offsetPosition : *CSSPrimitiveValue::createIdentifier(CSSValueAuto), important);
+
+        if (!offsetAnchor) {
+            CSSPrimitiveValue* fiftyPercent = CSSPrimitiveValue::create(50, CSSPrimitiveValue::UnitType::Percentage);
+            offsetAnchor = CSSValuePair::create(fiftyPercent, fiftyPercent, CSSValuePair::KeepIdenticalValues);
+        }
+        addProperty(CSSPropertyOffsetAnchor, CSSPropertyOffset, *offsetAnchor, important);
+    } else if (offsetPosition || offsetAnchor) {
+        // We could report a console warning "offset-position and offset-anchor are not yet supported."
+        return false;
+    }
+
+    addProperty(CSSPropertyOffsetPath, CSSPropertyOffset, offsetPath ? *offsetPath : *CSSPrimitiveValue::createIdentifier(CSSValueNone), important);
+
+    addProperty(CSSPropertyOffsetDistance, CSSPropertyOffset, offsetDistance ? *offsetDistance : *CSSPrimitiveValue::create(0, CSSPrimitiveValue::UnitType::Pixels), important);
+
+    if (!offsetRotation) {
+        CSSValueList* list = CSSValueList::createSpaceSeparated();
+        list->append(*CSSPrimitiveValue::createIdentifier(CSSValueAuto));
+        offsetRotation = list;
+    }
+    addProperty(CSSPropertyOffsetRotation, CSSPropertyOffset, *offsetRotation, important);
+
+    return m_range.atEnd();
+}
+
 static CSSValue* consumeZIndex(CSSParserTokenRange& range)
 {
     if (range.peek().id() == CSSValueAuto)
@@ -4657,7 +4706,7 @@ bool CSSPropertyParser::parseShorthand(CSSPropertyID unresolvedProperty, bool im
     case CSSPropertyMotion:
         return consumeShorthandGreedily(motionShorthand(), important);
     case CSSPropertyOffset:
-        return consumeShorthandGreedily(offsetShorthand(), important);
+        return consumeOffsetShorthand(important);
     case CSSPropertyWebkitTextEmphasis:
         return consumeShorthandGreedily(webkitTextEmphasisShorthand(), important);
     case CSSPropertyOutline: