Improved parse error handling for CSSMQ.

Source/core/css/CSSGrammar.y.in

Index: Source/core/css/CSSGrammar.y.in
diff --git a/Source/core/css/CSSGrammar.y.in b/Source/core/css/CSSGrammar.y.in
index a400d8c0c24d2c8532a52416570a6cf70db53410..9a25a37363eff28b23ff2ce21ed765ee428a88bf 100644
--- a/Source/core/css/CSSGrammar.y.in
+++ b/Source/core/css/CSSGrammar.y.in
@@ -4,6 +4,7 @@
  *  Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *  Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  *  Copyright (C) 2012 Intel Corporation. All rights reserved.
+ *  Copyright (C) 2013 Opera Software ASA. All rights reserved.
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
@@ -87,7 +88,7 @@ static inline bool isCSSTokenAString(int yytype)
 
 %}
 
-%expect 38
+%expect 36
 
 %nonassoc LOWEST_PREC
 
@@ -249,7 +250,7 @@ static inline bool isCSSTokenAString(int yytype)
 %type <string> media_feature
 %type <mediaList> media_list
 %type <mediaList> maybe_media_list
-%type <mediaQuery> media_query
+%type <mediaQuery> media_query invalid_media_query
 %type <mediaQueryRestrictor> maybe_media_restrictor
 %type <valueList> maybe_media_value
 %type <mediaQueryExp> media_query_exp
@@ -361,8 +362,14 @@ internal_value:
 ;
 
 webkit_mediaquery:
-     WEBKIT_MEDIAQUERY_SYM WHITESPACE maybe_space media_query '}' {
-         parser->m_mediaQuery = parser->sinkFloatingMediaQuery($4);
+     WEBKIT_MEDIAQUERY_SYM maybe_space media_query TOKEN_EOF {
+         parser->m_mediaQuery = parser->sinkFloatingMediaQuery($3);
+     }
+     | WEBKIT_MEDIAQUERY_SYM maybe_space media_query error TOKEN_EOF {
+         parser->m_mediaQuery = parser->sinkFloatingMediaQuery(parser->createFloatingMediaQuery(MediaQuery::Not, "all", parser->sinkFloatingMediaQueryExpList(parser->createFloatingMediaQueryExpList())));
+     }
+     | WEBKIT_MEDIAQUERY_SYM maybe_space error TOKEN_EOF {
+         parser->m_mediaQuery = parser->sinkFloatingMediaQuery(parser->createFloatingMediaQuery(MediaQuery::Not, "all", parser->sinkFloatingMediaQueryExpList(parser->createFloatingMediaQueryExpList())));
      }
 ;
 
@@ -582,15 +589,9 @@ maybe_media_value:
     ;
 
 media_query_exp:
-    maybe_media_restrictor maybe_space '(' maybe_space media_feature maybe_space maybe_media_value ')' maybe_space {
-        // If restrictor is specified, media query expression is invalid.
-        // Create empty media query expression and continue parsing media query.
-        if ($1 != MediaQuery::None)
-            $$ = parser->createFloatingMediaQueryExp("", 0);
-        else {
-            $5.lower();
-            $$ = parser->createFloatingMediaQueryExp($5, $7);
-        }
+    '(' maybe_space media_feature maybe_space maybe_media_value ')' maybe_space {
+        $3.lower();
+        $$ = parser->createFloatingMediaQueryExp($3, $5);
     }
     ;
 
@@ -630,35 +631,56 @@ media_query:
     media_query_exp_list {
         $$ = parser->createFloatingMediaQuery(parser->sinkFloatingMediaQueryExpList($1));
     }
-    |
-    maybe_media_restrictor maybe_space medium maybe_and_media_query_exp_list {
+    | maybe_media_restrictor maybe_space medium maybe_and_media_query_exp_list {
         $3.lower();
         $$ = parser->createFloatingMediaQuery($1, $3, parser->sinkFloatingMediaQueryExpList($4));
     }
+    | invalid_media_query maybe_space {
+        $$ = $1;
+    }
+    ;
+
+invalid_media_query:
+    error ',' {
+        $$ = parser->recoverMediaQuery();
+    }
+    | error '{' {
+        $$ = parser->recoverMediaQuery();
+    }
+    | error ';' {
+        $$ = parser->recoverMediaQuery();
+    }
+    | error '}' {
+        $$ = parser->recoverMediaQuery();
+    }
     ;
 
 maybe_media_list:
-     /* empty */ {
+    /* empty */ {
         $$ = parser->createMediaQuerySet();
-     }
-     | media_list
-     ;
+    }
+    | media_list
+    ;
+
+at_media_list_start:
+    /* empty */ {
+        parser->markMediaListStart();
+    }
+    ;
 
 media_list:
-    media_query {
+    at_media_list_start media_query {
         $$ = parser->createMediaQuerySet();
-        $$->addMediaQuery(parser->sinkFloatingMediaQuery($1));
+        $$->addMediaQuery(parser->sinkFloatingMediaQuery($2));
         parser->updateLastMediaLine($$);
     }
     | media_list ',' maybe_space media_query {
         $$ = $1;
-        if ($$) {
-            $$->addMediaQuery(parser->sinkFloatingMediaQuery($4));
-            parser->updateLastMediaLine($$);
-        }
+        $$->addMediaQuery(parser->sinkFloatingMediaQuery($4));
+        parser->updateLastMediaLine($$);
     }
-    | media_list error {
-        $$ = 0;
+    | media_list invalid_media_query maybe_space {
+        $$->replaceLastMediaQuery(parser->sinkFloatingMediaQuery($2));
     }
     ;
 
@@ -687,7 +709,11 @@ media:
     | before_media_rule MEDIA_SYM at_rule_header_end_maybe_space '{' at_rule_body_start maybe_space block_rule_list save_block {
         $$ = parser->createMediaRule(0, $7);
     }
-    | before_media_rule MEDIA_SYM at_rule_header_end_maybe_space ';' {
+    | before_media_rule MEDIA_SYM maybe_space media_list at_rule_header_end ';' {
+        $$ = 0;
+        parser->endRuleBody(true);
+    }
+    | before_media_rule MEDIA_SYM maybe_space media_list at_rule_header_end '}' {
         $$ = 0;
         parser->endRuleBody(true);
     }