Skeleton implementation of CSS Properties and Values API

third_party/WebKit/Source/core/css/CSSSyntaxDescriptor.cpp

+// 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/css/CSSSyntaxDescriptor.h"
+
+#include "core/css/CSSCustomPropertyDeclaration.h"
+#include "core/css/CSSURIValue.h"
+#include "core/css/CSSValueList.h"
+#include "core/css/CSSVariableReferenceValue.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+#include "core/css/parser/CSSTokenizer.h"
+#include "core/css/parser/CSSVariableParser.h"
+
+namespace blink {
+
+CSSSyntaxDescriptor::CSSSyntaxDescriptor(String input)
+{
+    // TODO(timloh): Implement proper parsing
+    if (input.contains('*'))
+        m_syntaxComponents.append(CSSSyntaxComponent(CSSSyntaxType::TokenStream));
+    else
+        m_syntaxComponents.append(CSSSyntaxComponent(CSSSyntaxType::Length));
+}
+
+const CSSValue* consumeSingleType(const CSSSyntaxComponent& syntax, CSSParserTokenRange& range)
+{
+    using namespace CSSPropertyParserHelpers;
+
+    // TODO(timloh): Calc values need to be normalized
+    switch (syntax.m_type) {
+    case CSSSyntaxType::Length:
+        return consumeLength(range, HTMLStandardMode, ValueRange::ValueRangeAll);
+    default:
+        NOTREACHED();
+        return nullptr;
+    }
+}
+
+const CSSValue* consumeSyntaxComponent(const CSSSyntaxComponent& syntax, CSSParserTokenRange range)
+{
+    // CSS-wide keywords are already handled by the CSSPropertyParser
+    const CSSValue* result = consumeSingleType(syntax, range);
+    if (!range.atEnd())
+        return nullptr;
+    return result;
+}
+
+const CSSValue* CSSSyntaxDescriptor::parse(const String& value) const
+{
+    CSSTokenizer::Scope scope(value);
+    return parse(scope.tokenRange());
+}
+
+const CSSValue* CSSSyntaxDescriptor::parse(CSSParserTokenRange range) const
+{
+    if (isTokenStream())
+        return CSSVariableParser::parseRegisteredPropertyValue(range, false);
+    range.consumeWhitespace();
+    for (const CSSSyntaxComponent& component : m_syntaxComponents) {
+        if (const CSSValue* result = consumeSyntaxComponent(component, range))
+            return result;
+    }
+    return CSSVariableParser::parseRegisteredPropertyValue(range, true);
+}
+
+} // namespace blink