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1// Copyright 2006 The Closure Library Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS-IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/**
16 * @fileoverview Bootstrap for the Google JS Library (Closure).
17 *
18 * In uncompiled mode base.js will write out Closure's deps file, unless the
19 * global <code>CLOSURE_NO_DEPS</code> is set to true.  This allows projects to
20 * include their own deps file(s) from different locations.
21 *
22 * @author pupius@google.com (Dan Pupius)
23 * @author arv@google.com (Erik Arvidsson)
24 *
25 * @provideGoog
26 */
27
28
29/**
30 * @define {boolean} Overridden to true by the compiler when --closure_pass
31 *     or --mark_as_compiled is specified.
32 */
33var COMPILED = false;
34
35
36/**
37 * Base namespace for the Closure library.  Checks to see goog is
38 * already defined in the current scope before assigning to prevent
39 * clobbering if base.js is loaded more than once.
40 *
41 * @const
42 */
43var goog = goog || {};
44
45
46/**
47 * Reference to the global context.  In most cases this will be 'window'.
48 */
49goog.global = this;
50
51
52/**
53 * A hook for overriding the define values in uncompiled mode.
54 *
55 * In uncompiled mode, {@code CLOSURE_DEFINES} may be defined before loading
56 * base.js.  If a key is defined in {@code CLOSURE_DEFINES}, {@code goog.define}
57 * will use the value instead of the default value.  This allows flags to be
58 * overwritten without compilation (this is normally accomplished with the
59 * compiler's "define" flag).
60 *
61 * Example:
62 * <pre>
63 *   var CLOSURE_DEFINES = {'goog.DEBUG', false};
64 * </pre>
65 *
66 * @type {Object.<string, (string|number|boolean)>|undefined}
67 */
68goog.global.CLOSURE_DEFINES;
69
70
71/**
72 * Builds an object structure for the provided namespace path,
73 * ensuring that names that already exist are not overwritten. For
74 * example:
75 * "a.b.c" -> a = {};a.b={};a.b.c={};
76 * Used by goog.provide and goog.exportSymbol.
77 * @param {string} name name of the object that this file defines.
78 * @param {*=} opt_object the object to expose at the end of the path.
79 * @param {Object=} opt_objectToExportTo The object to add the path to; default
80 *     is |goog.global|.
81 * @private
82 */
83goog.exportPath_ = function(name, opt_object, opt_objectToExportTo) {
84  var parts = name.split('.');
85  var cur = opt_objectToExportTo || goog.global;
86
87  // Internet Explorer exhibits strange behavior when throwing errors from
88  // methods externed in this manner.  See the testExportSymbolExceptions in
89  // base_test.html for an example.
90  if (!(parts[0] in cur) && cur.execScript) {
91    cur.execScript('var ' + parts[0]);
92  }
93
94  // Certain browsers cannot parse code in the form for((a in b); c;);
95  // This pattern is produced by the JSCompiler when it collapses the
96  // statement above into the conditional loop below. To prevent this from
97  // happening, use a for-loop and reserve the init logic as below.
98
99  // Parentheses added to eliminate strict JS warning in Firefox.
100  for (var part; parts.length && (part = parts.shift());) {
101    if (!parts.length && opt_object !== undefined) {
102      // last part and we have an object; use it
103      cur[part] = opt_object;
104    } else if (cur[part]) {
105      cur = cur[part];
106    } else {
107      cur = cur[part] = {};
108    }
109  }
110};
111
112
113/**
114 * Defines a named value. In uncompiled mode, the value is retreived from
115 * CLOSURE_DEFINES if the object is defined and has the property specified,
116 * and otherwise used the defined defaultValue. When compiled, the default
117 * can be overridden using compiler command-line options.
118 *
119 * @param {string} name The distinguished name to provide.
120 * @param {string|number|boolean} defaultValue
121 */
122goog.define = function(name, defaultValue) {
123  var value = defaultValue;
124  if (!COMPILED) {
125    if (goog.global.CLOSURE_DEFINES && Object.prototype.hasOwnProperty.call(
126        goog.global.CLOSURE_DEFINES, name)) {
127      value = goog.global.CLOSURE_DEFINES[name];
128    }
129  }
130  goog.exportPath_(name, value);
131};
132
133
134/**
135 * @define {boolean} DEBUG is provided as a convenience so that debugging code
136 * that should not be included in a production js_binary can be easily stripped
137 * by specifying --define goog.DEBUG=false to the JSCompiler. For example, most
138 * toString() methods should be declared inside an "if (goog.DEBUG)" conditional
139 * because they are generally used for debugging purposes and it is difficult
140 * for the JSCompiler to statically determine whether they are used.
141 */
142goog.DEBUG = true;
143
144
145/**
146 * @define {string} LOCALE defines the locale being used for compilation. It is
147 * used to select locale specific data to be compiled in js binary. BUILD rule
148 * can specify this value by "--define goog.LOCALE=<locale_name>" as JSCompiler
149 * option.
150 *
151 * Take into account that the locale code format is important. You should use
152 * the canonical Unicode format with hyphen as a delimiter. Language must be
153 * lowercase, Language Script - Capitalized, Region - UPPERCASE.
154 * There are few examples: pt-BR, en, en-US, sr-Latin-BO, zh-Hans-CN.
155 *
156 * See more info about locale codes here:
157 * http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers
158 *
159 * For language codes you should use values defined by ISO 693-1. See it here
160 * http://www.w3.org/WAI/ER/IG/ert/iso639.htm. There is only one exception from
161 * this rule: the Hebrew language. For legacy reasons the old code (iw) should
162 * be used instead of the new code (he), see http://wiki/Main/IIISynonyms.
163 */
164goog.define('goog.LOCALE', 'en');  // default to en
165
166
167/**
168 * @define {boolean} Whether this code is running on trusted sites.
169 *
170 * On untrusted sites, several native functions can be defined or overridden by
171 * external libraries like Prototype, Datejs, and JQuery and setting this flag
172 * to false forces closure to use its own implementations when possible.
173 *
174 * If your javascript can be loaded by a third party site and you are wary about
175 * relying on non-standard implementations, specify
176 * "--define goog.TRUSTED_SITE=false" to the JSCompiler.
177 */
178goog.define('goog.TRUSTED_SITE', true);
179
180
181/**
182 * Creates object stubs for a namespace.  The presence of one or more
183 * goog.provide() calls indicate that the file defines the given
184 * objects/namespaces.  Build tools also scan for provide/require statements
185 * to discern dependencies, build dependency files (see deps.js), etc.
186 * @see goog.require
187 * @param {string} name Namespace provided by this file in the form
188 *     "goog.package.part".
189 */
190goog.provide = function(name) {
191  if (!COMPILED) {
192    // Ensure that the same namespace isn't provided twice. This is intended
193    // to teach new developers that 'goog.provide' is effectively a variable
194    // declaration. And when JSCompiler transforms goog.provide into a real
195    // variable declaration, the compiled JS should work the same as the raw
196    // JS--even when the raw JS uses goog.provide incorrectly.
197    if (goog.isProvided_(name)) {
198      throw Error('Namespace "' + name + '" already declared.');
199    }
200    delete goog.implicitNamespaces_[name];
201
202    var namespace = name;
203    while ((namespace = namespace.substring(0, namespace.lastIndexOf('.')))) {
204      if (goog.getObjectByName(namespace)) {
205        break;
206      }
207      goog.implicitNamespaces_[namespace] = true;
208    }
209  }
210
211  goog.exportPath_(name);
212};
213
214
215/**
216 * Marks that the current file should only be used for testing, and never for
217 * live code in production.
218 *
219 * In the case of unit tests, the message may optionally be an exact
220 * namespace for the test (e.g. 'goog.stringTest'). The linter will then
221 * ignore the extra provide (if not explicitly defined in the code).
222 *
223 * @param {string=} opt_message Optional message to add to the error that's
224 *     raised when used in production code.
225 */
226goog.setTestOnly = function(opt_message) {
227  if (COMPILED && !goog.DEBUG) {
228    opt_message = opt_message || '';
229    throw Error('Importing test-only code into non-debug environment' +
230                opt_message ? ': ' + opt_message : '.');
231  }
232};
233
234
235if (!COMPILED) {
236
237  /**
238   * Check if the given name has been goog.provided. This will return false for
239   * names that are available only as implicit namespaces.
240   * @param {string} name name of the object to look for.
241   * @return {boolean} Whether the name has been provided.
242   * @private
243   */
244  goog.isProvided_ = function(name) {
245    return !goog.implicitNamespaces_[name] && !!goog.getObjectByName(name);
246  };
247
248  /**
249   * Namespaces implicitly defined by goog.provide. For example,
250   * goog.provide('goog.events.Event') implicitly declares
251   * that 'goog' and 'goog.events' must be namespaces.
252   *
253   * @type {Object}
254   * @private
255   */
256  goog.implicitNamespaces_ = {};
257}
258
259
260/**
261 * Returns an object based on its fully qualified external name.  If you are
262 * using a compilation pass that renames property names beware that using this
263 * function will not find renamed properties.
264 *
265 * @param {string} name The fully qualified name.
266 * @param {Object=} opt_obj The object within which to look; default is
267 *     |goog.global|.
268 * @return {?} The value (object or primitive) or, if not found, null.
269 */
270goog.getObjectByName = function(name, opt_obj) {
271  var parts = name.split('.');
272  var cur = opt_obj || goog.global;
273  for (var part; part = parts.shift(); ) {
274    if (goog.isDefAndNotNull(cur[part])) {
275      cur = cur[part];
276    } else {
277      return null;
278    }
279  }
280  return cur;
281};
282
283
284/**
285 * Globalizes a whole namespace, such as goog or goog.lang.
286 *
287 * @param {Object} obj The namespace to globalize.
288 * @param {Object=} opt_global The object to add the properties to.
289 * @deprecated Properties may be explicitly exported to the global scope, but
290 *     this should no longer be done in bulk.
291 */
292goog.globalize = function(obj, opt_global) {
293  var global = opt_global || goog.global;
294  for (var x in obj) {
295    global[x] = obj[x];
296  }
297};
298
299
300/**
301 * Adds a dependency from a file to the files it requires.
302 * @param {string} relPath The path to the js file.
303 * @param {Array} provides An array of strings with the names of the objects
304 *                         this file provides.
305 * @param {Array} requires An array of strings with the names of the objects
306 *                         this file requires.
307 */
308goog.addDependency = function(relPath, provides, requires) {
309  if (goog.DEPENDENCIES_ENABLED) {
310    var provide, require;
311    var path = relPath.replace(/\\/g, '/');
312    var deps = goog.dependencies_;
313    for (var i = 0; provide = provides[i]; i++) {
314      deps.nameToPath[provide] = path;
315      if (!(path in deps.pathToNames)) {
316        deps.pathToNames[path] = {};
317      }
318      deps.pathToNames[path][provide] = true;
319    }
320    for (var j = 0; require = requires[j]; j++) {
321      if (!(path in deps.requires)) {
322        deps.requires[path] = {};
323      }
324      deps.requires[path][require] = true;
325    }
326  }
327};
328
329
330// MOE:begin_strip
331/**
332 * Whether goog.require should throw an exception if it fails.
333 * @type {boolean}
334 */
335goog.useStrictRequires = false;
336
337
338// MOE:end_strip
339
340
341// NOTE(nnaze): The debug DOM loader was included in base.js as an orignal
342// way to do "debug-mode" development.  The dependency system can sometimes
343// be confusing, as can the debug DOM loader's asyncronous nature.
344//
345// With the DOM loader, a call to goog.require() is not blocking -- the
346// script will not load until some point after the current script.  If a
347// namespace is needed at runtime, it needs to be defined in a previous
348// script, or loaded via require() with its registered dependencies.
349// User-defined namespaces may need their own deps file.  See http://go/js_deps,
350// http://go/genjsdeps, or, externally, DepsWriter.
351// http://code.google.com/closure/library/docs/depswriter.html
352//
353// Because of legacy clients, the DOM loader can't be easily removed from
354// base.js.  Work is being done to make it disableable or replaceable for
355// different environments (DOM-less JavaScript interpreters like Rhino or V8,
356// for example). See bootstrap/ for more information.
357
358
359/**
360 * @define {boolean} Whether to enable the debug loader.
361 *
362 * If enabled, a call to goog.require() will attempt to load the namespace by
363 * appending a script tag to the DOM (if the namespace has been registered).
364 *
365 * If disabled, goog.require() will simply assert that the namespace has been
366 * provided (and depend on the fact that some outside tool correctly ordered
367 * the script).
368 */
369goog.define('goog.ENABLE_DEBUG_LOADER', true);
370
371
372/**
373 * Implements a system for the dynamic resolution of dependencies
374 * that works in parallel with the BUILD system. Note that all calls
375 * to goog.require will be stripped by the JSCompiler when the
376 * --closure_pass option is used.
377 * @see goog.provide
378 * @param {string} name Namespace to include (as was given in goog.provide())
379 *     in the form "goog.package.part".
380 */
381goog.require = function(name) {
382
383  // if the object already exists we do not need do do anything
384  // TODO(arv): If we start to support require based on file name this has
385  //            to change
386  // TODO(arv): If we allow goog.foo.* this has to change
387  // TODO(arv): If we implement dynamic load after page load we should probably
388  //            not remove this code for the compiled output
389  if (!COMPILED) {
390    if (goog.isProvided_(name)) {
391      return;
392    }
393
394    if (goog.ENABLE_DEBUG_LOADER) {
395      var path = goog.getPathFromDeps_(name);
396      if (path) {
397        goog.included_[path] = true;
398        goog.writeScripts_();
399        return;
400      }
401    }
402
403    var errorMessage = 'goog.require could not find: ' + name;
404    if (goog.global.console) {
405      goog.global.console['error'](errorMessage);
406    }
407
408    // MOE:begin_strip
409
410    // NOTE(nicksantos): We could always throw an error, but this would break
411    // legacy users that depended on this failing silently. Instead, the
412    // compiler should warn us when there are invalid goog.require calls.
413    // For now, we simply give clients a way to turn strict mode on.
414    if (goog.useStrictRequires) {
415      // MOE:end_strip
416
417      throw Error(errorMessage);
418
419      // MOE:begin_strip
420    }
421    // MOE:end_strip
422  }
423};
424
425
426/**
427 * Path for included scripts
428 * @type {string}
429 */
430goog.basePath = '';
431
432
433/**
434 * A hook for overriding the base path.
435 * @type {string|undefined}
436 */
437goog.global.CLOSURE_BASE_PATH;
438
439
440/**
441 * Whether to write out Closure's deps file. By default,
442 * the deps are written.
443 * @type {boolean|undefined}
444 */
445goog.global.CLOSURE_NO_DEPS;
446
447
448/**
449 * A function to import a single script. This is meant to be overridden when
450 * Closure is being run in non-HTML contexts, such as web workers. It's defined
451 * in the global scope so that it can be set before base.js is loaded, which
452 * allows deps.js to be imported properly.
453 *
454 * The function is passed the script source, which is a relative URI. It should
455 * return true if the script was imported, false otherwise.
456 */
457goog.global.CLOSURE_IMPORT_SCRIPT;
458
459
460/**
461 * Null function used for default values of callbacks, etc.
462 * @return {void} Nothing.
463 */
464goog.nullFunction = function() {};
465
466
467/**
468 * The identity function. Returns its first argument.
469 *
470 * @param {*=} opt_returnValue The single value that will be returned.
471 * @param {...*} var_args Optional trailing arguments. These are ignored.
472 * @return {?} The first argument. We can't know the type -- just pass it along
473 *      without type.
474 * @deprecated Use goog.functions.identity instead.
475 */
476goog.identityFunction = function(opt_returnValue, var_args) {
477  return opt_returnValue;
478};
479
480
481/**
482 * When defining a class Foo with an abstract method bar(), you can do:
483 *
484 * Foo.prototype.bar = goog.abstractMethod
485 *
486 * Now if a subclass of Foo fails to override bar(), an error
487 * will be thrown when bar() is invoked.
488 *
489 * Note: This does not take the name of the function to override as
490 * an argument because that would make it more difficult to obfuscate
491 * our JavaScript code.
492 *
493 * @type {!Function}
494 * @throws {Error} when invoked to indicate the method should be
495 *   overridden.
496 */
497goog.abstractMethod = function() {
498  throw Error('unimplemented abstract method');
499};
500
501
502/**
503 * Adds a {@code getInstance} static method that always return the same instance
504 * object.
505 * @param {!Function} ctor The constructor for the class to add the static
506 *     method to.
507 */
508goog.addSingletonGetter = function(ctor) {
509  ctor.getInstance = function() {
510    if (ctor.instance_) {
511      return ctor.instance_;
512    }
513    if (goog.DEBUG) {
514      // NOTE: JSCompiler can't optimize away Array#push.
515      goog.instantiatedSingletons_[goog.instantiatedSingletons_.length] = ctor;
516    }
517    return ctor.instance_ = new ctor;
518  };
519};
520
521
522/**
523 * All singleton classes that have been instantiated, for testing. Don't read
524 * it directly, use the {@code goog.testing.singleton} module. The compiler
525 * removes this variable if unused.
526 * @type {!Array.<!Function>}
527 * @private
528 */
529goog.instantiatedSingletons_ = [];
530
531
532/**
533 * True if goog.dependencies_ is available.
534 * @const {boolean}
535 */
536goog.DEPENDENCIES_ENABLED = !COMPILED && goog.ENABLE_DEBUG_LOADER;
537
538
539if (goog.DEPENDENCIES_ENABLED) {
540  /**
541   * Object used to keep track of urls that have already been added. This
542   * record allows the prevention of circular dependencies.
543   * @type {Object}
544   * @private
545   */
546  goog.included_ = {};
547
548
549  /**
550   * This object is used to keep track of dependencies and other data that is
551   * used for loading scripts
552   * @private
553   * @type {Object}
554   */
555  goog.dependencies_ = {
556    pathToNames: {}, // 1 to many
557    nameToPath: {}, // 1 to 1
558    requires: {}, // 1 to many
559    // used when resolving dependencies to prevent us from
560    // visiting the file twice
561    visited: {},
562    written: {} // used to keep track of script files we have written
563  };
564
565
566  /**
567   * Tries to detect whether is in the context of an HTML document.
568   * @return {boolean} True if it looks like HTML document.
569   * @private
570   */
571  goog.inHtmlDocument_ = function() {
572    var doc = goog.global.document;
573    return typeof doc != 'undefined' &&
574           'write' in doc;  // XULDocument misses write.
575  };
576
577
578  /**
579   * Tries to detect the base path of the base.js script that bootstraps Closure
580   * @private
581   */
582  goog.findBasePath_ = function() {
583    if (goog.global.CLOSURE_BASE_PATH) {
584      goog.basePath = goog.global.CLOSURE_BASE_PATH;
585      return;
586    } else if (!goog.inHtmlDocument_()) {
587      return;
588    }
589    var doc = goog.global.document;
590    var scripts = doc.getElementsByTagName('script');
591    // Search backwards since the current script is in almost all cases the one
592    // that has base.js.
593    for (var i = scripts.length - 1; i >= 0; --i) {
594      var src = scripts[i].src;
595      var qmark = src.lastIndexOf('?');
596      var l = qmark == -1 ? src.length : qmark;
597      if (src.substr(l - 7, 7) == 'base.js') {
598        goog.basePath = src.substr(0, l - 7);
599        return;
600      }
601    }
602  };
603
604
605  /**
606   * Imports a script if, and only if, that script hasn't already been imported.
607   * (Must be called at execution time)
608   * @param {string} src Script source.
609   * @private
610   */
611  goog.importScript_ = function(src) {
612    var importScript = goog.global.CLOSURE_IMPORT_SCRIPT ||
613        goog.writeScriptTag_;
614    if (!goog.dependencies_.written[src] && importScript(src)) {
615      goog.dependencies_.written[src] = true;
616    }
617  };
618
619
620  /**
621   * The default implementation of the import function. Writes a script tag to
622   * import the script.
623   *
624   * @param {string} src The script source.
625   * @return {boolean} True if the script was imported, false otherwise.
626   * @private
627   */
628  goog.writeScriptTag_ = function(src) {
629    if (goog.inHtmlDocument_()) {
630      var doc = goog.global.document;
631
632      // If the user tries to require a new symbol after document load,
633      // something has gone terribly wrong. Doing a document.write would
634      // wipe out the page.
635      if (doc.readyState == 'complete') {
636        // Certain test frameworks load base.js multiple times, which tries
637        // to write deps.js each time. If that happens, just fail silently.
638        // These frameworks wipe the page between each load of base.js, so this
639        // is OK.
640        var isDeps = /\bdeps.js$/.test(src);
641        if (isDeps) {
642          return false;
643        } else {
644          throw Error('Cannot write "' + src + '" after document load');
645        }
646      }
647
648      doc.write(
649          '<script type="text/javascript" src="' + src + '"></' + 'script>');
650      return true;
651    } else {
652      return false;
653    }
654  };
655
656
657  /**
658   * Resolves dependencies based on the dependencies added using addDependency
659   * and calls importScript_ in the correct order.
660   * @private
661   */
662  goog.writeScripts_ = function() {
663    // the scripts we need to write this time
664    var scripts = [];
665    var seenScript = {};
666    var deps = goog.dependencies_;
667
668    function visitNode(path) {
669      if (path in deps.written) {
670        return;
671      }
672
673      // we have already visited this one. We can get here if we have cyclic
674      // dependencies
675      if (path in deps.visited) {
676        if (!(path in seenScript)) {
677          seenScript[path] = true;
678          scripts.push(path);
679        }
680        return;
681      }
682
683      deps.visited[path] = true;
684
685      if (path in deps.requires) {
686        for (var requireName in deps.requires[path]) {
687          // If the required name is defined, we assume that it was already
688          // bootstrapped by other means.
689          if (!goog.isProvided_(requireName)) {
690            if (requireName in deps.nameToPath) {
691              visitNode(deps.nameToPath[requireName]);
692            } else {
693              throw Error('Undefined nameToPath for ' + requireName);
694            }
695          }
696        }
697      }
698
699      if (!(path in seenScript)) {
700        seenScript[path] = true;
701        scripts.push(path);
702      }
703    }
704
705    for (var path in goog.included_) {
706      if (!deps.written[path]) {
707        visitNode(path);
708      }
709    }
710
711    for (var i = 0; i < scripts.length; i++) {
712      if (scripts[i]) {
713        goog.importScript_(goog.basePath + scripts[i]);
714      } else {
715        throw Error('Undefined script input');
716      }
717    }
718  };
719
720
721  /**
722   * Looks at the dependency rules and tries to determine the script file that
723   * fulfills a particular rule.
724   * @param {string} rule In the form goog.namespace.Class or project.script.
725   * @return {?string} Url corresponding to the rule, or null.
726   * @private
727   */
728  goog.getPathFromDeps_ = function(rule) {
729    if (rule in goog.dependencies_.nameToPath) {
730      return goog.dependencies_.nameToPath[rule];
731    } else {
732      return null;
733    }
734  };
735
736  goog.findBasePath_();
737
738  // Allow projects to manage the deps files themselves.
739  if (!goog.global.CLOSURE_NO_DEPS) {
740    goog.importScript_(goog.basePath + 'deps.js');
741  }
742}
743
744
745
746//==============================================================================
747// Language Enhancements
748//==============================================================================
749
750
751/**
752 * This is a "fixed" version of the typeof operator.  It differs from the typeof
753 * operator in such a way that null returns 'null' and arrays return 'array'.
754 * @param {*} value The value to get the type of.
755 * @return {string} The name of the type.
756 */
757goog.typeOf = function(value) {
758  var s = typeof value;
759  if (s == 'object') {
760    if (value) {
761      // Check these first, so we can avoid calling Object.prototype.toString if
762      // possible.
763      //
764      // IE improperly marshals tyepof across execution contexts, but a
765      // cross-context object will still return false for "instanceof Object".
766      if (value instanceof Array) {
767        return 'array';
768      } else if (value instanceof Object) {
769        return s;
770      }
771
772      // HACK: In order to use an Object prototype method on the arbitrary
773      //   value, the compiler requires the value be cast to type Object,
774      //   even though the ECMA spec explicitly allows it.
775      var className = Object.prototype.toString.call(
776          /** @type {Object} */ (value));
777      // In Firefox 3.6, attempting to access iframe window objects' length
778      // property throws an NS_ERROR_FAILURE, so we need to special-case it
779      // here.
780      if (className == '[object Window]') {
781        return 'object';
782      }
783
784      // We cannot always use constructor == Array or instanceof Array because
785      // different frames have different Array objects. In IE6, if the iframe
786      // where the array was created is destroyed, the array loses its
787      // prototype. Then dereferencing val.splice here throws an exception, so
788      // we can't use goog.isFunction. Calling typeof directly returns 'unknown'
789      // so that will work. In this case, this function will return false and
790      // most array functions will still work because the array is still
791      // array-like (supports length and []) even though it has lost its
792      // prototype.
793      // Mark Miller noticed that Object.prototype.toString
794      // allows access to the unforgeable [[Class]] property.
795      //  15.2.4.2 Object.prototype.toString ( )
796      //  When the toString method is called, the following steps are taken:
797      //      1. Get the [[Class]] property of this object.
798      //      2. Compute a string value by concatenating the three strings
799      //         "[object ", Result(1), and "]".
800      //      3. Return Result(2).
801      // and this behavior survives the destruction of the execution context.
802      if ((className == '[object Array]' ||
803           // In IE all non value types are wrapped as objects across window
804           // boundaries (not iframe though) so we have to do object detection
805           // for this edge case
806           typeof value.length == 'number' &&
807           typeof value.splice != 'undefined' &&
808           typeof value.propertyIsEnumerable != 'undefined' &&
809           !value.propertyIsEnumerable('splice')
810
811          )) {
812        return 'array';
813      }
814      // HACK: There is still an array case that fails.
815      //     function ArrayImpostor() {}
816      //     ArrayImpostor.prototype = [];
817      //     var impostor = new ArrayImpostor;
818      // this can be fixed by getting rid of the fast path
819      // (value instanceof Array) and solely relying on
820      // (value && Object.prototype.toString.vall(value) === '[object Array]')
821      // but that would require many more function calls and is not warranted
822      // unless closure code is receiving objects from untrusted sources.
823
824      // IE in cross-window calls does not correctly marshal the function type
825      // (it appears just as an object) so we cannot use just typeof val ==
826      // 'function'. However, if the object has a call property, it is a
827      // function.
828      if ((className == '[object Function]' ||
829          typeof value.call != 'undefined' &&
830          typeof value.propertyIsEnumerable != 'undefined' &&
831          !value.propertyIsEnumerable('call'))) {
832        return 'function';
833      }
834
835
836    } else {
837      return 'null';
838    }
839
840  } else if (s == 'function' && typeof value.call == 'undefined') {
841    // In Safari typeof nodeList returns 'function', and on Firefox
842    // typeof behaves similarly for HTML{Applet,Embed,Object}Elements
843    // and RegExps.  We would like to return object for those and we can
844    // detect an invalid function by making sure that the function
845    // object has a call method.
846    return 'object';
847  }
848  return s;
849};
850
851
852/**
853 * Returns true if the specified value is not |undefined|.
854 * WARNING: Do not use this to test if an object has a property. Use the in
855 * operator instead.  Additionally, this function assumes that the global
856 * undefined variable has not been redefined.
857 * @param {*} val Variable to test.
858 * @return {boolean} Whether variable is defined.
859 */
860goog.isDef = function(val) {
861  return val !== undefined;
862};
863
864
865/**
866 * Returns true if the specified value is |null|
867 * @param {*} val Variable to test.
868 * @return {boolean} Whether variable is null.
869 */
870goog.isNull = function(val) {
871  return val === null;
872};
873
874
875/**
876 * Returns true if the specified value is defined and not null
877 * @param {*} val Variable to test.
878 * @return {boolean} Whether variable is defined and not null.
879 */
880goog.isDefAndNotNull = function(val) {
881  // Note that undefined == null.
882  return val != null;
883};
884
885
886/**
887 * Returns true if the specified value is an array
888 * @param {*} val Variable to test.
889 * @return {boolean} Whether variable is an array.
890 */
891goog.isArray = function(val) {
892  return goog.typeOf(val) == 'array';
893};
894
895
896/**
897 * Returns true if the object looks like an array. To qualify as array like
898 * the value needs to be either a NodeList or an object with a Number length
899 * property.
900 * @param {*} val Variable to test.
901 * @return {boolean} Whether variable is an array.
902 */
903goog.isArrayLike = function(val) {
904  var type = goog.typeOf(val);
905  return type == 'array' || type == 'object' && typeof val.length == 'number';
906};
907
908
909/**
910 * Returns true if the object looks like a Date. To qualify as Date-like
911 * the value needs to be an object and have a getFullYear() function.
912 * @param {*} val Variable to test.
913 * @return {boolean} Whether variable is a like a Date.
914 */
915goog.isDateLike = function(val) {
916  return goog.isObject(val) && typeof val.getFullYear == 'function';
917};
918
919
920/**
921 * Returns true if the specified value is a string
922 * @param {*} val Variable to test.
923 * @return {boolean} Whether variable is a string.
924 */
925goog.isString = function(val) {
926  return typeof val == 'string';
927};
928
929
930/**
931 * Returns true if the specified value is a boolean
932 * @param {*} val Variable to test.
933 * @return {boolean} Whether variable is boolean.
934 */
935goog.isBoolean = function(val) {
936  return typeof val == 'boolean';
937};
938
939
940/**
941 * Returns true if the specified value is a number
942 * @param {*} val Variable to test.
943 * @return {boolean} Whether variable is a number.
944 */
945goog.isNumber = function(val) {
946  return typeof val == 'number';
947};
948
949
950/**
951 * Returns true if the specified value is a function
952 * @param {*} val Variable to test.
953 * @return {boolean} Whether variable is a function.
954 */
955goog.isFunction = function(val) {
956  return goog.typeOf(val) == 'function';
957};
958
959
960/**
961 * Returns true if the specified value is an object.  This includes arrays
962 * and functions.
963 * @param {*} val Variable to test.
964 * @return {boolean} Whether variable is an object.
965 */
966goog.isObject = function(val) {
967  var type = typeof val;
968  return type == 'object' && val != null || type == 'function';
969  // return Object(val) === val also works, but is slower, especially if val is
970  // not an object.
971};
972
973
974/**
975 * Gets a unique ID for an object. This mutates the object so that further
976 * calls with the same object as a parameter returns the same value. The unique
977 * ID is guaranteed to be unique across the current session amongst objects that
978 * are passed into {@code getUid}. There is no guarantee that the ID is unique
979 * or consistent across sessions. It is unsafe to generate unique ID for
980 * function prototypes.
981 *
982 * @param {Object} obj The object to get the unique ID for.
983 * @return {number} The unique ID for the object.
984 */
985goog.getUid = function(obj) {
986  // TODO(arv): Make the type stricter, do not accept null.
987
988  // In Opera window.hasOwnProperty exists but always returns false so we avoid
989  // using it. As a consequence the unique ID generated for BaseClass.prototype
990  // and SubClass.prototype will be the same.
991  return obj[goog.UID_PROPERTY_] ||
992      (obj[goog.UID_PROPERTY_] = ++goog.uidCounter_);
993};
994
995
996/**
997 * Removes the unique ID from an object. This is useful if the object was
998 * previously mutated using {@code goog.getUid} in which case the mutation is
999 * undone.
1000 * @param {Object} obj The object to remove the unique ID field from.
1001 */
1002goog.removeUid = function(obj) {
1003  // TODO(arv): Make the type stricter, do not accept null.
1004
1005  // DOM nodes in IE are not instance of Object and throws exception
1006  // for delete. Instead we try to use removeAttribute
1007  if ('removeAttribute' in obj) {
1008    obj.removeAttribute(goog.UID_PROPERTY_);
1009  }
1010  /** @preserveTry */
1011  try {
1012    delete obj[goog.UID_PROPERTY_];
1013  } catch (ex) {
1014  }
1015};
1016
1017
1018/**
1019 * Name for unique ID property. Initialized in a way to help avoid collisions
1020 * with other closure javascript on the same page.
1021 * @type {string}
1022 * @private
1023 */
1024goog.UID_PROPERTY_ = 'closure_uid_' + ((Math.random() * 1e9) >>> 0);
1025
1026
1027/**
1028 * Counter for UID.
1029 * @type {number}
1030 * @private
1031 */
1032goog.uidCounter_ = 0;
1033
1034
1035/**
1036 * Adds a hash code field to an object. The hash code is unique for the
1037 * given object.
1038 * @param {Object} obj The object to get the hash code for.
1039 * @return {number} The hash code for the object.
1040 * @deprecated Use goog.getUid instead.
1041 */
1042goog.getHashCode = goog.getUid;
1043
1044
1045/**
1046 * Removes the hash code field from an object.
1047 * @param {Object} obj The object to remove the field from.
1048 * @deprecated Use goog.removeUid instead.
1049 */
1050goog.removeHashCode = goog.removeUid;
1051
1052
1053/**
1054 * Clones a value. The input may be an Object, Array, or basic type. Objects and
1055 * arrays will be cloned recursively.
1056 *
1057 * WARNINGS:
1058 * <code>goog.cloneObject</code> does not detect reference loops. Objects that
1059 * refer to themselves will cause infinite recursion.
1060 *
1061 * <code>goog.cloneObject</code> is unaware of unique identifiers, and copies
1062 * UIDs created by <code>getUid</code> into cloned results.
1063 *
1064 * @param {*} obj The value to clone.
1065 * @return {*} A clone of the input value.
1066 * @deprecated goog.cloneObject is unsafe. Prefer the goog.object methods.
1067 */
1068goog.cloneObject = function(obj) {
1069  var type = goog.typeOf(obj);
1070  if (type == 'object' || type == 'array') {
1071    if (obj.clone) {
1072      return obj.clone();
1073    }
1074    var clone = type == 'array' ? [] : {};
1075    for (var key in obj) {
1076      clone[key] = goog.cloneObject(obj[key]);
1077    }
1078    return clone;
1079  }
1080
1081  return obj;
1082};
1083
1084
1085/**
1086 * A native implementation of goog.bind.
1087 * @param {Function} fn A function to partially apply.
1088 * @param {Object|undefined} selfObj Specifies the object which |this| should
1089 *     point to when the function is run.
1090 * @param {...*} var_args Additional arguments that are partially
1091 *     applied to the function.
1092 * @return {!Function} A partially-applied form of the function bind() was
1093 *     invoked as a method of.
1094 * @private
1095 * @suppress {deprecated} The compiler thinks that Function.prototype.bind
1096 *     is deprecated because some people have declared a pure-JS version.
1097 *     Only the pure-JS version is truly deprecated.
1098 */
1099goog.bindNative_ = function(fn, selfObj, var_args) {
1100  return /** @type {!Function} */ (fn.call.apply(fn.bind, arguments));
1101};
1102
1103
1104/**
1105 * A pure-JS implementation of goog.bind.
1106 * @param {Function} fn A function to partially apply.
1107 * @param {Object|undefined} selfObj Specifies the object which |this| should
1108 *     point to when the function is run.
1109 * @param {...*} var_args Additional arguments that are partially
1110 *     applied to the function.
1111 * @return {!Function} A partially-applied form of the function bind() was
1112 *     invoked as a method of.
1113 * @private
1114 */
1115goog.bindJs_ = function(fn, selfObj, var_args) {
1116  if (!fn) {
1117    throw new Error();
1118  }
1119
1120  if (arguments.length > 2) {
1121    var boundArgs = Array.prototype.slice.call(arguments, 2);
1122    return function() {
1123      // Prepend the bound arguments to the current arguments.
1124      var newArgs = Array.prototype.slice.call(arguments);
1125      Array.prototype.unshift.apply(newArgs, boundArgs);
1126      return fn.apply(selfObj, newArgs);
1127    };
1128
1129  } else {
1130    return function() {
1131      return fn.apply(selfObj, arguments);
1132    };
1133  }
1134};
1135
1136
1137/**
1138 * Partially applies this function to a particular 'this object' and zero or
1139 * more arguments. The result is a new function with some arguments of the first
1140 * function pre-filled and the value of |this| 'pre-specified'.<br><br>
1141 *
1142 * Remaining arguments specified at call-time are appended to the pre-
1143 * specified ones.<br><br>
1144 *
1145 * Also see: {@link #partial}.<br><br>
1146 *
1147 * Usage:
1148 * <pre>var barMethBound = bind(myFunction, myObj, 'arg1', 'arg2');
1149 * barMethBound('arg3', 'arg4');</pre>
1150 *
1151 * @param {?function(this:T, ...)} fn A function to partially apply.
1152 * @param {T} selfObj Specifies the object which |this| should
1153 *     point to when the function is run.
1154 * @param {...*} var_args Additional arguments that are partially
1155 *     applied to the function.
1156 * @return {!Function} A partially-applied form of the function bind() was
1157 *     invoked as a method of.
1158 * @template T
1159 * @suppress {deprecated} See above.
1160 */
1161goog.bind = function(fn, selfObj, var_args) {
1162  // TODO(nicksantos): narrow the type signature.
1163  if (Function.prototype.bind &&
1164      // NOTE(nicksantos): Somebody pulled base.js into the default
1165      // Chrome extension environment. This means that for Chrome extensions,
1166      // they get the implementation of Function.prototype.bind that
1167      // calls goog.bind instead of the native one. Even worse, we don't want
1168      // to introduce a circular dependency between goog.bind and
1169      // Function.prototype.bind, so we have to hack this to make sure it
1170      // works correctly.
1171      Function.prototype.bind.toString().indexOf('native code') != -1) {
1172    goog.bind = goog.bindNative_;
1173  } else {
1174    goog.bind = goog.bindJs_;
1175  }
1176  return goog.bind.apply(null, arguments);
1177};
1178
1179
1180/**
1181 * Like bind(), except that a 'this object' is not required. Useful when the
1182 * target function is already bound.
1183 *
1184 * Usage:
1185 * var g = partial(f, arg1, arg2);
1186 * g(arg3, arg4);
1187 *
1188 * @param {Function} fn A function to partially apply.
1189 * @param {...*} var_args Additional arguments that are partially
1190 *     applied to fn.
1191 * @return {!Function} A partially-applied form of the function bind() was
1192 *     invoked as a method of.
1193 */
1194goog.partial = function(fn, var_args) {
1195  var args = Array.prototype.slice.call(arguments, 1);
1196  return function() {
1197    // Prepend the bound arguments to the current arguments.
1198    var newArgs = Array.prototype.slice.call(arguments);
1199    newArgs.unshift.apply(newArgs, args);
1200    return fn.apply(this, newArgs);
1201  };
1202};
1203
1204
1205/**
1206 * Copies all the members of a source object to a target object. This method
1207 * does not work on all browsers for all objects that contain keys such as
1208 * toString or hasOwnProperty. Use goog.object.extend for this purpose.
1209 * @param {Object} target Target.
1210 * @param {Object} source Source.
1211 */
1212goog.mixin = function(target, source) {
1213  for (var x in source) {
1214    target[x] = source[x];
1215  }
1216
1217  // For IE7 or lower, the for-in-loop does not contain any properties that are
1218  // not enumerable on the prototype object (for example, isPrototypeOf from
1219  // Object.prototype) but also it will not include 'replace' on objects that
1220  // extend String and change 'replace' (not that it is common for anyone to
1221  // extend anything except Object).
1222};
1223
1224
1225/**
1226 * @return {number} An integer value representing the number of milliseconds
1227 *     between midnight, January 1, 1970 and the current time.
1228 */
1229goog.now = (goog.TRUSTED_SITE && Date.now) || (function() {
1230  // Unary plus operator converts its operand to a number which in the case of
1231  // a date is done by calling getTime().
1232  return +new Date();
1233});
1234
1235
1236/**
1237 * Evals javascript in the global scope.  In IE this uses execScript, other
1238 * browsers use goog.global.eval. If goog.global.eval does not evaluate in the
1239 * global scope (for example, in Safari), appends a script tag instead.
1240 * Throws an exception if neither execScript or eval is defined.
1241 * @param {string} script JavaScript string.
1242 */
1243goog.globalEval = function(script) {
1244  if (goog.global.execScript) {
1245    goog.global.execScript(script, 'JavaScript');
1246  } else if (goog.global.eval) {
1247    // Test to see if eval works
1248    if (goog.evalWorksForGlobals_ == null) {
1249      goog.global.eval('var _et_ = 1;');
1250      if (typeof goog.global['_et_'] != 'undefined') {
1251        delete goog.global['_et_'];
1252        goog.evalWorksForGlobals_ = true;
1253      } else {
1254        goog.evalWorksForGlobals_ = false;
1255      }
1256    }
1257
1258    if (goog.evalWorksForGlobals_) {
1259      goog.global.eval(script);
1260    } else {
1261      var doc = goog.global.document;
1262      var scriptElt = doc.createElement('script');
1263      scriptElt.type = 'text/javascript';
1264      scriptElt.defer = false;
1265      // Note(pupius): can't use .innerHTML since "t('<test>')" will fail and
1266      // .text doesn't work in Safari 2.  Therefore we append a text node.
1267      scriptElt.appendChild(doc.createTextNode(script));
1268      doc.body.appendChild(scriptElt);
1269      doc.body.removeChild(scriptElt);
1270    }
1271  } else {
1272    throw Error('goog.globalEval not available');
1273  }
1274};
1275
1276
1277/**
1278 * Indicates whether or not we can call 'eval' directly to eval code in the
1279 * global scope. Set to a Boolean by the first call to goog.globalEval (which
1280 * empirically tests whether eval works for globals). @see goog.globalEval
1281 * @type {?boolean}
1282 * @private
1283 */
1284goog.evalWorksForGlobals_ = null;
1285
1286
1287/**
1288 * Optional map of CSS class names to obfuscated names used with
1289 * goog.getCssName().
1290 * @type {Object|undefined}
1291 * @private
1292 * @see goog.setCssNameMapping
1293 */
1294goog.cssNameMapping_;
1295
1296
1297/**
1298 * Optional obfuscation style for CSS class names. Should be set to either
1299 * 'BY_WHOLE' or 'BY_PART' if defined.
1300 * @type {string|undefined}
1301 * @private
1302 * @see goog.setCssNameMapping
1303 */
1304goog.cssNameMappingStyle_;
1305
1306
1307/**
1308 * Handles strings that are intended to be used as CSS class names.
1309 *
1310 * This function works in tandem with @see goog.setCssNameMapping.
1311 *
1312 * Without any mapping set, the arguments are simple joined with a
1313 * hyphen and passed through unaltered.
1314 *
1315 * When there is a mapping, there are two possible styles in which
1316 * these mappings are used. In the BY_PART style, each part (i.e. in
1317 * between hyphens) of the passed in css name is rewritten according
1318 * to the map. In the BY_WHOLE style, the full css name is looked up in
1319 * the map directly. If a rewrite is not specified by the map, the
1320 * compiler will output a warning.
1321 *
1322 * When the mapping is passed to the compiler, it will replace calls
1323 * to goog.getCssName with the strings from the mapping, e.g.
1324 *     var x = goog.getCssName('foo');
1325 *     var y = goog.getCssName(this.baseClass, 'active');
1326 *  becomes:
1327 *     var x= 'foo';
1328 *     var y = this.baseClass + '-active';
1329 *
1330 * If one argument is passed it will be processed, if two are passed
1331 * only the modifier will be processed, as it is assumed the first
1332 * argument was generated as a result of calling goog.getCssName.
1333 *
1334 * @param {string} className The class name.
1335 * @param {string=} opt_modifier A modifier to be appended to the class name.
1336 * @return {string} The class name or the concatenation of the class name and
1337 *     the modifier.
1338 */
1339goog.getCssName = function(className, opt_modifier) {
1340  var getMapping = function(cssName) {
1341    return goog.cssNameMapping_[cssName] || cssName;
1342  };
1343
1344  var renameByParts = function(cssName) {
1345    // Remap all the parts individually.
1346    var parts = cssName.split('-');
1347    var mapped = [];
1348    for (var i = 0; i < parts.length; i++) {
1349      mapped.push(getMapping(parts[i]));
1350    }
1351    return mapped.join('-');
1352  };
1353
1354  var rename;
1355  if (goog.cssNameMapping_) {
1356    rename = goog.cssNameMappingStyle_ == 'BY_WHOLE' ?
1357        getMapping : renameByParts;
1358  } else {
1359    rename = function(a) {
1360      return a;
1361    };
1362  }
1363
1364  if (opt_modifier) {
1365    return className + '-' + rename(opt_modifier);
1366  } else {
1367    return rename(className);
1368  }
1369};
1370
1371
1372/**
1373 * Sets the map to check when returning a value from goog.getCssName(). Example:
1374 * <pre>
1375 * goog.setCssNameMapping({
1376 *   "goog": "a",
1377 *   "disabled": "b",
1378 * });
1379 *
1380 * var x = goog.getCssName('goog');
1381 * // The following evaluates to: "a a-b".
1382 * goog.getCssName('goog') + ' ' + goog.getCssName(x, 'disabled')
1383 * </pre>
1384 * When declared as a map of string literals to string literals, the JSCompiler
1385 * will replace all calls to goog.getCssName() using the supplied map if the
1386 * --closure_pass flag is set.
1387 *
1388 * @param {!Object} mapping A map of strings to strings where keys are possible
1389 *     arguments to goog.getCssName() and values are the corresponding values
1390 *     that should be returned.
1391 * @param {string=} opt_style The style of css name mapping. There are two valid
1392 *     options: 'BY_PART', and 'BY_WHOLE'.
1393 * @see goog.getCssName for a description.
1394 */
1395goog.setCssNameMapping = function(mapping, opt_style) {
1396  goog.cssNameMapping_ = mapping;
1397  goog.cssNameMappingStyle_ = opt_style;
1398};
1399
1400
1401/**
1402 * To use CSS renaming in compiled mode, one of the input files should have a
1403 * call to goog.setCssNameMapping() with an object literal that the JSCompiler
1404 * can extract and use to replace all calls to goog.getCssName(). In uncompiled
1405 * mode, JavaScript code should be loaded before this base.js file that declares
1406 * a global variable, CLOSURE_CSS_NAME_MAPPING, which is used below. This is
1407 * to ensure that the mapping is loaded before any calls to goog.getCssName()
1408 * are made in uncompiled mode.
1409 *
1410 * A hook for overriding the CSS name mapping.
1411 * @type {Object|undefined}
1412 */
1413goog.global.CLOSURE_CSS_NAME_MAPPING;
1414
1415
1416if (!COMPILED && goog.global.CLOSURE_CSS_NAME_MAPPING) {
1417  // This does not call goog.setCssNameMapping() because the JSCompiler
1418  // requires that goog.setCssNameMapping() be called with an object literal.
1419  goog.cssNameMapping_ = goog.global.CLOSURE_CSS_NAME_MAPPING;
1420}
1421
1422
1423/**
1424 * Gets a localized message.
1425 *
1426 * This function is a compiler primitive. If you give the compiler a localized
1427 * message bundle, it will replace the string at compile-time with a localized
1428 * version, and expand goog.getMsg call to a concatenated string.
1429 *
1430 * Messages must be initialized in the form:
1431 * <code>
1432 * var MSG_NAME = goog.getMsg('Hello {$placeholder}', {'placeholder': 'world'});
1433 * </code>
1434 *
1435 * @param {string} str Translatable string, places holders in the form {$foo}.
1436 * @param {Object=} opt_values Map of place holder name to value.
1437 * @return {string} message with placeholders filled.
1438 */
1439goog.getMsg = function(str, opt_values) {
1440  var values = opt_values || {};
1441  for (var key in values) {
1442    var value = ('' + values[key]).replace(/\$/g, '$$$$');
1443    str = str.replace(new RegExp('\\{\\$' + key + '\\}', 'gi'), value);
1444  }
1445  return str;
1446};
1447
1448
1449/**
1450 * Gets a localized message. If the message does not have a translation, gives a
1451 * fallback message.
1452 *
1453 * This is useful when introducing a new message that has not yet been
1454 * translated into all languages.
1455 *
1456 * This function is a compiler primtive. Must be used in the form:
1457 * <code>var x = goog.getMsgWithFallback(MSG_A, MSG_B);</code>
1458 * where MSG_A and MSG_B were initialized with goog.getMsg.
1459 *
1460 * @param {string} a The preferred message.
1461 * @param {string} b The fallback message.
1462 * @return {string} The best translated message.
1463 */
1464goog.getMsgWithFallback = function(a, b) {
1465  return a;
1466};
1467
1468
1469/**
1470 * Exposes an unobfuscated global namespace path for the given object.
1471 * Note that fields of the exported object *will* be obfuscated,
1472 * unless they are exported in turn via this function or
1473 * goog.exportProperty
1474 *
1475 * <p>Also handy for making public items that are defined in anonymous
1476 * closures.
1477 *
1478 * ex. goog.exportSymbol('public.path.Foo', Foo);
1479 *
1480 * ex. goog.exportSymbol('public.path.Foo.staticFunction',
1481 *                       Foo.staticFunction);
1482 *     public.path.Foo.staticFunction();
1483 *
1484 * ex. goog.exportSymbol('public.path.Foo.prototype.myMethod',
1485 *                       Foo.prototype.myMethod);
1486 *     new public.path.Foo().myMethod();
1487 *
1488 * @param {string} publicPath Unobfuscated name to export.
1489 * @param {*} object Object the name should point to.
1490 * @param {Object=} opt_objectToExportTo The object to add the path to; default
1491 *     is |goog.global|.
1492 */
1493goog.exportSymbol = function(publicPath, object, opt_objectToExportTo) {
1494  goog.exportPath_(publicPath, object, opt_objectToExportTo);
1495};
1496
1497
1498/**
1499 * Exports a property unobfuscated into the object's namespace.
1500 * ex. goog.exportProperty(Foo, 'staticFunction', Foo.staticFunction);
1501 * ex. goog.exportProperty(Foo.prototype, 'myMethod', Foo.prototype.myMethod);
1502 * @param {Object} object Object whose static property is being exported.
1503 * @param {string} publicName Unobfuscated name to export.
1504 * @param {*} symbol Object the name should point to.
1505 */
1506goog.exportProperty = function(object, publicName, symbol) {
1507  object[publicName] = symbol;
1508};
1509
1510
1511/**
1512 * Inherit the prototype methods from one constructor into another.
1513 *
1514 * Usage:
1515 * <pre>
1516 * function ParentClass(a, b) { }
1517 * ParentClass.prototype.foo = function(a) { }
1518 *
1519 * function ChildClass(a, b, c) {
1520 *   goog.base(this, a, b);
1521 * }
1522 * goog.inherits(ChildClass, ParentClass);
1523 *
1524 * var child = new ChildClass('a', 'b', 'see');
1525 * child.foo(); // works
1526 * </pre>
1527 *
1528 * In addition, a superclass' implementation of a method can be invoked
1529 * as follows:
1530 *
1531 * <pre>
1532 * ChildClass.prototype.foo = function(a) {
1533 *   ChildClass.superClass_.foo.call(this, a);
1534 *   // other code
1535 * };
1536 * </pre>
1537 *
1538 * @param {Function} childCtor Child class.
1539 * @param {Function} parentCtor Parent class.
1540 */
1541goog.inherits = function(childCtor, parentCtor) {
1542  /** @constructor */
1543  function tempCtor() {};
1544  tempCtor.prototype = parentCtor.prototype;
1545  childCtor.superClass_ = parentCtor.prototype;
1546  childCtor.prototype = new tempCtor();
1547  /** @override */
1548  childCtor.prototype.constructor = childCtor;
1549};
1550
1551
1552/**
1553 * Call up to the superclass.
1554 *
1555 * If this is called from a constructor, then this calls the superclass
1556 * contructor with arguments 1-N.
1557 *
1558 * If this is called from a prototype method, then you must pass
1559 * the name of the method as the second argument to this function. If
1560 * you do not, you will get a runtime error. This calls the superclass'
1561 * method with arguments 2-N.
1562 *
1563 * This function only works if you use goog.inherits to express
1564 * inheritance relationships between your classes.
1565 *
1566 * This function is a compiler primitive. At compile-time, the
1567 * compiler will do macro expansion to remove a lot of
1568 * the extra overhead that this function introduces. The compiler
1569 * will also enforce a lot of the assumptions that this function
1570 * makes, and treat it as a compiler error if you break them.
1571 *
1572 * @param {!Object} me Should always be "this".
1573 * @param {*=} opt_methodName The method name if calling a super method.
1574 * @param {...*} var_args The rest of the arguments.
1575 * @return {*} The return value of the superclass method.
1576 */
1577goog.base = function(me, opt_methodName, var_args) {
1578  var caller = arguments.callee.caller;
1579
1580  if (goog.DEBUG) {
1581    if (!caller) {
1582      throw Error('arguments.caller not defined.  goog.base() expects not ' +
1583                  'to be running in strict mode. See ' +
1584                  'http://www.ecma-international.org/ecma-262/5.1/#sec-C');
1585    }
1586  }
1587
1588  if (caller.superClass_) {
1589    // This is a constructor. Call the superclass constructor.
1590    return caller.superClass_.constructor.apply(
1591        me, Array.prototype.slice.call(arguments, 1));
1592  }
1593
1594  var args = Array.prototype.slice.call(arguments, 2);
1595  var foundCaller = false;
1596  for (var ctor = me.constructor;
1597       ctor; ctor = ctor.superClass_ && ctor.superClass_.constructor) {
1598    if (ctor.prototype[opt_methodName] === caller) {
1599      foundCaller = true;
1600    } else if (foundCaller) {
1601      return ctor.prototype[opt_methodName].apply(me, args);
1602    }
1603  }
1604
1605  // If we did not find the caller in the prototype chain,
1606  // then one of two things happened:
1607  // 1) The caller is an instance method.
1608  // 2) This method was not called by the right caller.
1609  if (me[opt_methodName] === caller) {
1610    return me.constructor.prototype[opt_methodName].apply(me, args);
1611  } else {
1612    throw Error(
1613        'goog.base called from a method of one name ' +
1614        'to a method of a different name');
1615  }
1616};
1617
1618
1619/**
1620 * Allow for aliasing within scope functions.  This function exists for
1621 * uncompiled code - in compiled code the calls will be inlined and the
1622 * aliases applied.  In uncompiled code the function is simply run since the
1623 * aliases as written are valid JavaScript.
1624 * @param {function()} fn Function to call.  This function can contain aliases
1625 *     to namespaces (e.g. "var dom = goog.dom") or classes
1626 *    (e.g. "var Timer = goog.Timer").
1627 */
1628goog.scope = function(fn) {
1629  fn.call(goog.global);
1630};
1631
1632
1633// MOE:begin_strip
1634
1635// The section between this token and the end token below will be stripped
1636// automatically by the open source release scripts.  Please leave in place.
1637
1638//==============================================================================
1639// Extending Function
1640//==============================================================================
1641
1642
1643/**
1644 * @define {boolean} Whether to extend Function.prototype.
1645 *     Use --define='goog.MODIFY_FUNCTION_PROTOTYPES=false' to change.
1646 */
1647goog.define('goog.MODIFY_FUNCTION_PROTOTYPES', true);
1648
1649if (goog.MODIFY_FUNCTION_PROTOTYPES) {
1650  /**
1651   * An alias to the {@link goog.bind()} global function.
1652   *
1653   * Usage:
1654   * var g = f.bind(obj, arg1, arg2);
1655   * g(arg3, arg4);
1656   *
1657   * @param {Object} selfObj Specifies the object to which |this| should point
1658   *     when the function is run. If the value is null or undefined, it will
1659   *     default to the global object.
1660   * @param {...*} var_args Additional arguments that are partially
1661   *     applied to fn.
1662   * @return {!Function} A partially-applied form of the Function on which
1663   *     bind() was invoked as a method.
1664   * @deprecated Use the static function goog.bind instead.
1665   * @suppress {duplicate}
1666   */
1667  Function.prototype.bind =
1668      Function.prototype.bind || function(selfObj, var_args) {
1669    if (arguments.length > 1) {
1670      var args = Array.prototype.slice.call(arguments, 1);
1671      args.unshift(this, selfObj);
1672      return goog.bind.apply(null, args);
1673    } else {
1674      return goog.bind(this, selfObj);
1675    }
1676  };
1677
1678
1679  /**
1680   * An alias to the {@link goog.partial()} static function.
1681   *
1682   * Usage:
1683   * var g = f.partial(arg1, arg2);
1684   * g(arg3, arg4);
1685   *
1686   * @param {...*} var_args Additional arguments that are partially
1687   *     applied to fn.
1688   * @return {!Function} A partially-applied form of the function partial() was
1689   *     invoked as a method of.
1690   * @deprecated Use the static function goog.partial instead.
1691   */
1692  Function.prototype.partial = function(var_args) {
1693    var args = Array.prototype.slice.call(arguments);
1694    args.unshift(this, null);
1695    return goog.bind.apply(null, args);
1696  };
1697
1698
1699  /**
1700   * Inherit the prototype methods from one constructor into another.
1701   * @param {Function} parentCtor Parent class.
1702   * @see goog.inherits
1703   * @deprecated Use the static function goog.inherits instead.
1704   */
1705  Function.prototype.inherits = function(parentCtor) {
1706    goog.inherits(this, parentCtor);
1707  };
1708
1709
1710  /**
1711   * Mixes in an object's properties and methods into the callee's prototype.
1712   * Basically mixin based inheritance, thus providing an alternative method for
1713   * adding properties and methods to a class' prototype.
1714   *
1715   * <pre>
1716   * function X() {}
1717   * X.mixin({
1718   *   one: 1,
1719   *   two: 2,
1720   *   three: 3,
1721   *   doit: function() { return this.one + this.two + this.three; }
1722   * });
1723   *
1724   * function Y() { }
1725   * Y.mixin(X.prototype);
1726   * Y.prototype.four = 15;
1727   * Y.prototype.doit2 = function() { return this.doit() + this.four; }
1728   * });
1729   *
1730   * // or
1731   *
1732   * function Y() { }
1733   * Y.inherits(X);
1734   * Y.mixin({
1735   *   one: 10,
1736   *   four: 15,
1737   *   doit2: function() { return this.doit() + this.four; }
1738   * });
1739   * </pre>
1740   *
1741   * @param {Object} source from which to copy properties.
1742   * @see goog.mixin
1743   * @deprecated Use the static function goog.object.extend instead.
1744   */
1745  Function.prototype.mixin = function(source) {
1746    goog.mixin(this.prototype, source);
1747  };
1748}
1749
1750// MOE:end_strip
1751