1 /*

     2 Copyright (c) 2009, Yahoo! Inc. All rights reserved.

     3 Code licensed under the BSD License:

     4 http://developer.yahoo.net/yui/license.txt

     5 version: 3.0.0b1

     6 build: 1163

     7 */

     8 YUI.add('json-parse', function(Y) {

     9 

    10 /**

    11  * <p>The JSON module adds support for serializing JavaScript objects into

    12  * JSON strings and parsing JavaScript objects from strings in JSON format.</p>

    13  *

    14  * <p>The JSON namespace is added to your YUI instance including static methods

    15  * Y.JSON.parse(..) and Y.JSON.stringify(..).</p>

    16  *

    17  * <p>The functionality and method signatures follow the ECMAScript 5

    18  * specification.  In browsers with native JSON support, the native

    19  * implementation is used.</p>

    20  *

    21  * <p>The <code>json</code> module is a rollup of <code>json-parse</code> and

    22  * <code>json-stringify</code>.</p>

    23  * 

    24  * <p>As their names suggest, <code>json-parse</code> adds support for parsing

    25  * JSON data (Y.JSON.parse) and <code>json-stringify</code> for serializing

    26  * JavaScript data into JSON strings (Y.JSON.stringify).  You may choose to

    27  * include either of the submodules individually if you don't need the

    28  * complementary functionality, or include the rollup for both.</p>

    29  *

    30  * @module json

    31  * @class JSON

    32  * @static

    33  */

    34 

    35 /**

    36  * Provides Y.JSON.parse method to accept JSON strings and return native

    37  * JavaScript objects.

    38  *

    39  * @module json

    40  * @submodule json-parse

    41  * @for JSON

    42  * @static

    43  */

    44 

    45 

    46 // All internals kept private for security reasons

    47 

    48 

    49     /**

    50      * Alias to native browser implementation of the JSON object if available.

    51      *

    52      * @property Native

    53      * @type {Object}

    54      * @private

    55      */

    56 var Native = Y.config.win.JSON,

    57 

    58     /**

    59      * Replace certain Unicode characters that JavaScript may handle incorrectly

    60      * during eval--either by deleting them or treating them as line

    61      * endings--with escape sequences.

    62      * IMPORTANT NOTE: This regex will be used to modify the input if a match is

    63      * found.

    64      *

    65      * @property _UNICODE_EXCEPTIONS

    66      * @type {RegExp}

    67      * @private

    68      */

    69     _UNICODE_EXCEPTIONS = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,

    70 

    71 

    72     /**

    73      * First step in the safety evaluation.  Regex used to replace all escape

    74      * sequences (i.e. "\\", etc) with '@' characters (a non-JSON character).

    75      *

    76      * @property _ESCAPES

    77      * @type {RegExp}

    78      * @private

    79      */

    80     _ESCAPES = /\\(?:["\\\/bfnrt]|u[0-9a-fA-F]{4})/g,

    81 

    82     /**

    83      * Second step in the safety evaluation.  Regex used to replace all simple

    84      * values with ']' characters.

    85      *

    86      * @property _VALUES

    87      * @type {RegExp}

    88      * @private

    89      */

    90     _VALUES  = /"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?/g,

    91 

    92     /**

    93      * Third step in the safety evaluation.  Regex used to remove all open

    94      * square brackets following a colon, comma, or at the beginning of the

    95      * string.

    96      *

    97      * @property _BRACKETS

    98      * @type {RegExp}

    99      * @private

   100      */

   101     _BRACKETS = /(?:^|:|,)(?:\s*\[)+/g,

   102 

   103     /**

   104      * Final step in the safety evaluation.  Regex used to test the string left

   105      * after all previous replacements for invalid characters.

   106      *

   107      * @property _INVALID

   108      * @type {RegExp}

   109      * @private

   110      */

   111     _INVALID = /[^\],:{}\s]/,

   112     

   113     /**

   114      * Test for JSON string of simple data string, number, boolean, or null.

   115      * E.g. '"some string"', "true", "false", "null", or numbers "-123e+7"

   116      * This was needed for some WIP native implementations (FF3.1b2) but may be

   117      * unnecessary now.

   118      *

   119      * @property _SIMPLE

   120      * @type {RegExp}

   121      * @private

   122      */

   123     _SIMPLE = /^\s*(?:"[^"\\\n\r]*"|true|false|null|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)\s*$/,

   124 

   125     /**

   126      * Replaces specific unicode characters with their appropriate \unnnn

   127      * format. Some browsers ignore certain characters during eval.

   128      *

   129      * @method escapeException

   130      * @param c {String} Unicode character

   131      * @return {String} the \unnnn escapement of the character

   132      * @private

   133      */

   134     _escapeException = function (c) {

   135         return '\\u'+('0000'+(+(c.charCodeAt(0))).toString(16)).slice(-4);

   136     },

   137 

   138     /**

   139      * Traverses nested objects, applying a reviver function to each (key,value)

   140      * from the scope if the key:value's containing object.  The value returned

   141      * from the function will replace the original value in the key:value pair.

   142      * If the value returned is undefined, the key will be omitted from the

   143      * returned object.

   144      *

   145      * @method _revive

   146      * @param data {MIXED} Any JavaScript data

   147      * @param reviver {Function} filter or mutation function

   148      * @return {MIXED} The results of the filtered data

   149      * @private

   150      */

   151     _revive = function (data, reviver) {

   152         var walk = function (o,key) {

   153             var k,v,value = o[key];

   154             if (value && typeof value === 'object') {

   155                 for (k in value) {

   156                     if (value.hasOwnProperty(k)) {

   157                         v = walk(value, k);

   158                         if (v === undefined) {

   159                             delete value[k];

   160                         } else {

   161                             value[k] = v;

   162                         }

   163                     }

   164                 }

   165             }

   166             return reviver.call(o,key,value);

   167         };

   168 

   169         return typeof reviver === 'function' ? walk({'':data},'') : data;

   170     },

   171 

   172     /**

   173      * Parse a JSON string, returning the native JavaScript representation.

   174      *

   175      * @param s {string} JSON string data

   176      * @param reviver {function} (optional) function(k,v) passed each key value

   177      *          pair of object literals, allowing pruning or altering values

   178      * @return {MIXED} the native JavaScript representation of the JSON string

   179      * @throws SyntaxError

   180      * @method parse

   181      * @static

   182      */

   183     // JavaScript implementation in lieu of native browser support.  Based on

   184     // the json2.js library from http://json.org

   185     _parse = function (s,reviver) {

   186         if (typeof s === 'string') {

   187             // Replace certain Unicode characters that are otherwise handled

   188             // incorrectly by some browser implementations.

   189             // NOTE: This modifies the input if such characters are found!

   190             s = s.replace(_UNICODE_EXCEPTIONS, _escapeException);

   191             

   192             // Test for any remaining invalid characters

   193             if (!_INVALID.test(s.replace(_ESCAPES,'@').

   194                                  replace(_VALUES,']').

   195                                  replace(_BRACKETS,''))) {

   196 

   197                 // Eval the text into a JavaScript data structure, apply any

   198                 // reviver function, and return

   199                 return _revive( eval('(' + s + ')'), reviver );

   200             }

   201         }

   202 

   203         throw new SyntaxError('JSON.parse');

   204     },

   205     

   206     test;

   207 

   208 

   209 // Test the level of native browser support

   210 if (Native && Object.prototype.toString.call(Native) === '[object JSON]') {

   211     try {

   212         test = Native.parse('{"x":1}', function (k,v) {return k=='x' ? 2 : v;});

   213         switch (test.x) {

   214             case 1 : // Reviver not supported

   215                 _parse = function (s,reviver) {

   216                     return _SIMPLE.test(s) ?

   217                             eval('(' + s + ')') :

   218                             _revive(Native.parse(s), reviver);

   219                 };

   220                 break;

   221 

   222             case 2 : // Full support

   223                 _parse = function (s, reviver) {

   224                     return Native.parse(s, reviver);

   225                 };

   226                 break;

   227 

   228             // default is JS implementation

   229         }

   230     }

   231     catch (e) {} // defer to JS implementation

   232 }

   233 

   234 Y.mix(Y.namespace('JSON'),{ parse : _parse });

   235 

   236 

   237 }, '3.0.0b1' );