Get Media Query parser to handle parens, brackets and braces blocks correctly

Source/core/css/parser/MediaQueryParser.cpp

Index: Source/core/css/parser/MediaQueryParser.cpp
diff --git a/Source/core/css/parser/MediaQueryParser.cpp b/Source/core/css/parser/MediaQueryParser.cpp
index a4afb61bc34c592f2bb66661b740e6d19a0a0ce5..81e17520d1a4bf255c69a9aa4783896a04bad416 100644
--- a/Source/core/css/parser/MediaQueryParser.cpp
+++ b/Source/core/css/parser/MediaQueryParser.cpp
@@ -25,7 +25,7 @@ const MediaQueryParser::State MediaQueryParser::ReadFeatureColon = &MediaQueryPa
 const MediaQueryParser::State MediaQueryParser::ReadFeatureValue = &MediaQueryParser::readFeatureValue;
 const MediaQueryParser::State MediaQueryParser::ReadFeatureEnd = &MediaQueryParser::readFeatureEnd;
 const MediaQueryParser::State MediaQueryParser::SkipUntilComma = &MediaQueryParser::skipUntilComma;
-const MediaQueryParser::State MediaQueryParser::SkipUntilParenthesis = &MediaQueryParser::skipUntilParenthesis;
+const MediaQueryParser::State MediaQueryParser::SkipUntilBlockEnd = &MediaQueryParser::skipUntilBlockEnd;
 const MediaQueryParser::State MediaQueryParser::Done = &MediaQueryParser::done;
 
 // FIXME: Replace the MediaQueryTokenizer with a generic CSSTokenizer, once there is one,
@@ -111,7 +111,7 @@ void MediaQueryParser::readFeatureColon(MediaQueryTokenType type, TokenIterator&
         --token;
         m_state = ReadFeatureEnd;
     } else {
-        m_state = SkipUntilParenthesis;
+        m_state = SkipUntilBlockEnd;
     }
 }
 
@@ -136,7 +136,7 @@ void MediaQueryParser::readFeatureEnd(MediaQueryTokenType type, TokenIterator& t
         m_mediaQueryData.addParserValue(type, *token);
         m_state = ReadFeatureValue;
     } else {
-        m_state = SkipUntilParenthesis;
+        m_state = SkipUntilBlockEnd;
     }
 }
 
@@ -149,18 +149,55 @@ void MediaQueryParser::skipUntilComma(MediaQueryTokenType type, TokenIterator& t
     }
 }
 
-void MediaQueryParser::skipUntilParenthesis(MediaQueryTokenType type, TokenIterator& token)
+void MediaQueryParser::skipUntilBlockEnd(MediaQueryTokenType type, TokenIterator& token)
 {
-    if (type == RightParenthesisToken)
+    if (m_blockStack.isEmpty())

[eseidel, 2014/04/01 21:15:08]

I'm not sure I understand this.  I guess it depends on how it's called?  What
states can cause us to start skipping? do tdhey all want this comma behavior? 
Maybe this comma behavior should be explicit in the callsites?

         m_state = SkipUntilComma;
 }
 
 void MediaQueryParser::done(MediaQueryTokenType type, TokenIterator& token) { }
 
+void MediaQueryParser::popIfBlockMatches(Vector<BlockType>& blockStack, BlockType type)
+{
+    if (!blockStack.isEmpty() && blockStack.last() == type)
+        blockStack.removeLast();
+}
+
+bool MediaQueryParser::observeBlock(BlockParameters& parameters, MediaQueryTokenType type)
+{
+    if (type == parameters.lefttoken) {
+        if (parameters.stateChange == ModifyState)
+            m_state = SkipUntilBlockEnd;
+        m_blockStack.append(parameters.blockType);
+    } else if (type == parameters.righttoken) {
+        popIfBlockMatches(m_blockStack, parameters.blockType);
+    } else {
+        return false;
+    }
+    return true;
+}
+
+void MediaQueryParser::observeBlocks(MediaQueryTokenType type)
+{
+    const unsigned blockParametersNumber = 3;
+    BlockParameters blockParameterSet[blockParametersNumber] = {
+        { LeftParenthesisToken, RightParenthesisToken, ParenthesisBlock, DoNotModifyState },
+        { LeftBracketToken, RightBracketToken, BracketsBlock, ModifyState },

[eseidel, 2014/04/01 21:15:08]

What does "modify state" mean?  It appears to me "colapse verything between
start and end into a single token?"

+        { LeftBraceToken, RightBraceToken, BracesBlock, ModifyState }
+    };
+
+    for (unsigned i = 0; i < blockParametersNumber; ++i) {
+        if (observeBlock(blockParameterSet[i], type))
+            break;
+    }
+}
+
 void MediaQueryParser::processToken(TokenIterator& token)
 {
     MediaQueryTokenType type = token->type();
 
+    observeBlocks(type);
+
     // Call the function that handles current state
     if (type != WhitespaceToken && type != CommentToken)
         ((this)->*(m_state))(type, token);