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);

[alancutter (OOO until 2018), 2014/12/29 05:10:22]

Would it be worse to have consumeComponentValue() return trailingNestingLevel?

[Timothy Loh, 2015/01/05 05:56:18]

I don't think it's any worse, but we're going to rewrite these before shipping
anyway and these will be super short then so I'm not too concerned about how
this looks right now.

+
+    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