CSS Custom Properties (Variables)

Source/core/css/parser/CSSPropertyParser.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 16 matching lines @@
 #include "config.h"
 #include "core/css/parser/CSSPropertyParser.h"
 
 #include "core/StylePropertyShorthand.h"
 #include "core/css/CSSBasicShapes.h"
 #include "core/css/CSSBorderImage.h"
 #include "core/css/CSSCanvasValue.h"
 #include "core/css/CSSContentDistributionValue.h"
 #include "core/css/CSSCrossfadeValue.h"
 #include "core/css/CSSCursorImageValue.h"
+#include "core/css/CSSCustomVariableValue.h"
 #include "core/css/CSSFontFaceSrcValue.h"
 #include "core/css/CSSFontFeatureValue.h"
 #include "core/css/CSSFunctionValue.h"
 #include "core/css/CSSGridLineNamesValue.h"
 #include "core/css/CSSImageSetValue.h"
 #include "core/css/CSSImageValue.h"
 #include "core/css/CSSLineBoxContainValue.h"
 #include "core/css/CSSPathValue.h"
 #include "core/css/CSSPrimitiveValueMappings.h"
 #include "core/css/CSSProperty.h"
@@ skipping 410 matching lines @@
             return false;
         addExpandedPropertyForValue(propId, cssValuePool().createExplicitInitialValue(), important);
         return true;
     } else if (id == CSSValueUnset) {
         if (m_valueList->size() != 1)
             return false;
         addExpandedPropertyForValue(propId, cssValuePool().createUnsetValue(), important);
         return true;
     }
 
+    if (RuntimeEnabledFeatures::cssVariablesEnabled() && value->unit() == CSSPrimitiveValue::UnitType::VariableReference) {
+        // We don't expand the shorthand here because crazypants.

[alancutter (OOO until 2018), 2015/08/25 01:59:08]

There are issues with letting shorthands into the system beyond parse time. The
font shorthand is lower priority than font-size so things that use ems will be
computed incorrectly. There may be other places that aren't equipped to handle
shorthand properties in parsed style rules.

We should be implementing what the spec specifies with pending-substitution
values otherwise getting CSSOM correctness will be uglypants.
https://drafts.csswg.org/css-variables/#variables-in-shorthands

Let's not support shorthands with var() for now until we have
pending-substitution values.

[Timothy Loh, 2015/08/25 09:21:10]

I'm not sure shorthands even fall into a priority bucket right now. Discarding
shorthands using var() at parse-time with a TODO sgtm.

+        m_parsedProperties.append(CSSProperty(propId, CSSPrimitiveValue::create(value->variableData), important, false, 0, m_implicitShorthand));
+        m_valueList->next();
+        return true;
+    }
+
     if (CSSParserFastPaths::isKeywordPropertyID(propId)) {
         if (!CSSParserFastPaths::isValidKeywordPropertyAndValue(propId, id))
             return false;
         if (m_valueList->next() && !inShorthand())
             return false;
         addProperty(propId, cssValuePool().createIdentifierValue(id), important);
         return true;
     }
 
     bool validPrimitive = false;
@@ skipping 7630 matching lines @@
         }
     }
 
     if (!list->length())
         return nullptr;
 
     return list.release();
 }
 
 } // namespace blink