Added validating JSON parser mode to parser.

src/scanner.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 234 matching lines @@
       token_ = keyword_token;
       return true;
     }
     return false;
   }
 
   void Step(uc32 input);
 };
 
 
+enum ParserMode { PARSE, PREPARSE };
+enum ParserLanguage { JAVASCRIPT, JSON };
+
+
 class Scanner {
  public:
-
   typedef unibrow::Utf8InputBuffer<1024> Utf8Decoder;
 
   // Construction
-  explicit Scanner(bool is_pre_parsing);
+  explicit Scanner(ParserMode parse_mode);
 
   // Initialize the Scanner to scan source:
   void Init(Handle<String> source,
             unibrow::CharacterStream* stream,
-            int position);
+            int position,
+            ParserLanguage language);
 
   // Returns the next token.
   Token::Value Next();
 
   // One token look-ahead (past the token returned by Next()).
   Token::Value peek() const  { return next_.token; }
 
   // Returns true if there was a line terminator before the peek'ed token.
   bool has_line_terminator_before_next() const {
     return has_line_terminator_before_next_;
@@ skipping 93 matching lines @@
   struct TokenDesc {
     Token::Value token;
     Location location;
     UTF8Buffer* literal_buffer;
   };
 
   TokenDesc current_;  // desc for current token (as returned by Next())
   TokenDesc next_;     // desc for next token (one token look-ahead)
   bool has_line_terminator_before_next_;
   bool is_pre_parsing_;
+  bool is_parsing_json_;
 
   // Literal buffer support
   void StartLiteral();
   void AddChar(uc32 ch);
   void AddCharAdvance();
   void TerminateLiteral();
 
   // Low-level scanning support.
   void Advance() { c0_ = source_->Advance(); }
   void PushBack(uc32 ch) {
     source_->PushBack(ch);
     c0_ = ch;
   }
 
-  bool SkipWhiteSpace();
+  bool SkipWhiteSpace() {
+    if (is_parsing_json_) {
+      return SkipJsonWhiteSpace();
+    } else {
+      return SkipJavaScriptWhiteSpace();
+    }
+  }
+  bool SkipJavaScriptWhiteSpace();
+  bool SkipJsonWhiteSpace();
   Token::Value SkipSingleLineComment();
   Token::Value SkipMultiLineComment();
 
   inline Token::Value Select(Token::Value tok);
   inline Token::Value Select(uc32 next, Token::Value then, Token::Value else_);
 
-  void Scan();
+  inline void Scan() {
+    if (is_parsing_json_) {
+      ScanJson();
+    } else {
+      ScanJavaScript();
+    }
+  }
+  void ScanJson();
+  void ScanJavaScript();
+
+  Token::Value ScanJsonNumber();

[Mads Ager (chromium), 2010/02/01 08:42:19]

For each of these Scan functions, please add a comment explaining (at least some
of the ways in which) JSON scanning differs from JavaScript scanning.  Also,
there are probably spec references that would make sense to add here for quick
reference.

+  Token::Value ScanJsonString();
+  Token::Value ScanJsonIdentifier(const char* text, Token::Value token);
+
   void ScanDecimalDigits();
   Token::Value ScanNumber(bool seen_period);
   Token::Value ScanIdentifier();
   uc32 ScanHexEscape(uc32 c, int length);
   uc32 ScanOctalEscape(uc32 c, int length);
   void ScanEscape();
   Token::Value ScanString();
 
   // Scans a possible HTML comment -- begins with '<!'.
   Token::Value ScanHtmlComment();
 
   // Return the current source position.
   int source_pos() {
     return source_->pos() - kCharacterLookaheadBufferSize + position_;
   }
 
   // Decodes a unicode escape-sequence which is part of an identifier.
   // If the escape sequence cannot be decoded the result is kBadRune.
   uc32 ScanIdentifierUnicodeEscape();
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCANNER_H_