CSS Parser: Implement parseRule

Source/core/css/parser/CSSParserTokenRange.cpp

 // Copyright 2014 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 "config.h"
 #include "core/css/parser/CSSParserTokenRange.h"
 
 #include "wtf/StaticConstructors.h"
 
 namespace blink {
 
 DEFINE_GLOBAL(CSSParserToken, staticEOFToken);
 
 void CSSParserTokenRange::initStaticEOFToken()
 {
     new ((void*)&staticEOFToken) CSSParserToken(EOFToken);
 }
 
 CSSParserTokenRange CSSParserTokenRange::makeSubRange(const CSSParserToken* first, const CSSParserToken* last)
 {
     if (first == &staticEOFToken)
         first = m_last;
     if (last == &staticEOFToken)
         last = m_last;
     ASSERT(first <= last);
     return CSSParserTokenRange(first, last);
 }
 
+CSSParserTokenRange CSSParserTokenRange::consumeBlock()
+{
+    ASSERT(peek().blockType() == CSSParserToken::BlockStart);
+    const CSSParserToken* start = &peek() + 1;
+    unsigned nestingLevel = 0;
+    do {
+        const CSSParserToken& token = consume();
+        if (token.blockType() == CSSParserToken::BlockStart)
+            nestingLevel++;
+        else if (token.blockType() == CSSParserToken::BlockEnd)
+            nestingLevel--;
+    } while (nestingLevel && m_first < m_last);
+
+    if (nestingLevel)
+        return makeSubRange(start, m_first); // Ended at EOF
+    return makeSubRange(start, m_first - 1);
+}
+
 void CSSParserTokenRange::consumeComponentValue()
 {
     // FIXME: This is going to do multiple passes over large sections of a stylesheet.
     // We should consider optimising this by precomputing where each block ends.
     unsigned nestingLevel = 0;
     do {
         const CSSParserToken& token = consume();
         if (token.blockType() == CSSParserToken::BlockStart)
             nestingLevel++;
         else if (token.blockType() == CSSParserToken::BlockEnd)
             nestingLevel--;
     } while (nestingLevel && m_first < m_last);
 }
 
 void CSSParserTokenRange::consumeWhitespaceAndComments()
 {
     while (peek().type() == WhitespaceToken || peek().type() == CommentToken)
         ++m_first;
 }
 
 } // namespace blink