Create stand-alone json parser (including scanner).

src/json-parser.h

Index: src/json-parser.h
===================================================================
--- src/json-parser.h	(revision 0)
+++ src/json-parser.h	(revision 0)
@@ -0,0 +1,161 @@
+// Copyright 2011 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_JSON_PARSER_H_
+#define V8_JSON_PARSER_H_
+
+#include "token.h"
+
+namespace v8 {
+namespace internal {
+
+// A simple json parser.
+class JsonParser BASE_EMBEDDED {
+ public:
+  static Handle<Object> Parse(Handle<String> source) {
+    return JsonParser().ParseJson(source);
+  }
+
+  static const int kEndOfString = -1;
+
+ private:
+  // Parse a string containing a single JSON value.
+  Handle<Object> ParseJson(Handle<String> source);
+
+  inline void Advance() {
+    if (position_ >= source_length_) {
+      position_++;
+      c0_ = kEndOfString;
+    } else if (is_sequential_ascii_) {
+      position_++;
+      c0_ = seq_source_->SeqAsciiStringGet(position_);
+    } else {
+      position_++;
+      c0_ = source_->Get(position_);
+    }
+  }
+
+  inline Isolate* isolate() { return isolate_; }
+
+  // Get the string for the current string token.
+  Handle<String> GetString(bool hint_symbol);
+  Handle<String> GetString();
+  Handle<String> GetSymbol();
+
+  // Scan a single JSON token. The JSON lexical grammar is specified in the
+  // ECMAScript 5 standard, section 15.12.1.1.
+  // Recognizes all of the single-character tokens directly, or calls a function
+  // to scan a number, string or identifier literal.
+  // The only allowed whitespace characters between tokens are tab,
+  // carriage-return, newline and space.
+  void ScanJson();
+
+  // A JSON string (production JSONString) is subset of valid JavaScript string
+  // literals. The string must only be double-quoted (not single-quoted), and
+  // the only allowed backslash-escapes are ", /, \, b, f, n, r, t and
+  // four-digit hex escapes (uXXXX). Any other use of backslashes is invalid.
+  Token::Value ScanJsonString();
+  // Slow version for unicode support, uses the first ascii_count characters,
+  // as first part of a ConsString
+  Token::Value SlowScanJsonString();
+
+  // A JSON number (production JSONNumber) is a subset of the valid JavaScript
+  // decimal number literals.
+  // It includes an optional minus sign, must have at least one
+  // digit before and after a decimal point, may not have prefixed zeros (unless
+  // the integer part is zero), and may include an exponent part (e.g., "e-10").
+  // Hexadecimal and octal numbers are not allowed.
+  Token::Value ScanJsonNumber();
+
+  // Used to recognizes one of the literals "true", "false", or "null". These
+  // are the only valid JSON identifiers (productions JSONBooleanLiteral,
+  // JSONNullLiteral).
+  Token::Value ScanJsonIdentifier(const char* text, Token::Value token);
+
+  // Parse a single JSON value from input (grammar production JSONValue).
+  // A JSON value is either a (double-quoted) string literal, a number literal,
+  // one of "true", "false", or "null", or an object or array literal.
+  Handle<Object> ParseJsonValue();
+
+  // Parse a JSON object literal (grammar production JSONObject).
+  // An object literal is a squiggly-braced and comma separated sequence
+  // (possibly empty) of key/value pairs, where the key is a JSON string
+  // literal, the value is a JSON value, and the two are separated by a colon.
+  // A JSON array dosn't allow numbers and identifiers as keys, like a
+  // JavaScript array.
+  Handle<Object> ParseJsonObject();
+
+  // Parses a JSON array literal (grammar production JSONArray). An array
+  // literal is a square-bracketed and comma separated sequence (possibly empty)
+  // of JSON values.
+  // A JSON array doesn't allow leaving out values from the sequence, nor does
+  // it allow a terminal comma, like a JavaScript array does.
+  Handle<Object> ParseJsonArray();
+
+
+  // Mark that a parsing error has happened at the current token, and
+  // return a null handle. Primarily for readability.
+  Handle<Object> ReportUnexpectedToken() { return Handle<Object>::null(); }
+
+  // Peek at the next token.
+  Token::Value Peek() { return next_.token; }
+  // Scan the next token and return the token scanned on the last call.
+  Token::Value Next();
+
+  struct TokenInfo {
+    TokenInfo() : token(Token::ILLEGAL),
+                  beg_pos(0),
+                  end_pos(0) { }
+    Token::Value token;
+    int beg_pos;
+    int end_pos;
+  };
+
+  static const int kInitialSpecialStringSize = 100;
+
+
+ private:
+  Handle<String> source_;
+  int source_length_;
+  Handle<SeqAsciiString> seq_source_;
+
+  bool is_sequential_ascii_;
+  // Current and next token
+  TokenInfo current_;
+  TokenInfo next_;
+  Isolate* isolate_;
+  uc32 c0_;
+  int position_;
+
+
+  Handle<String> string_val_;
+  double number_;
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_JSON_PARSER_H_