lib/goog/base.js

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 arv@google.com (Erik Arvidsson)
23 *
24 * @provideGoog
25 */
26
27
28/**
29 * @define {boolean} Overridden to true by the compiler when
30 * --process_closure_primitives is specified.
31 */
32var COMPILED = false;
33
34
35/**
36 * Base namespace for the Closure library. Checks to see goog is already
37 * defined in the current scope before assigning to prevent clobbering if
38 * base.js is loaded more than once.
39 *
40 * @const
41 */
42var goog = goog || {};
43
44
45/**
46 * Reference to the global context. In most cases this will be 'window'.
47 */
48goog.global = this;
49
50
51/**
52 * A hook for overriding the define values in uncompiled mode.
53 *
54 * In uncompiled mode, {@code CLOSURE_UNCOMPILED_DEFINES} may be defined before
55 * loading base.js. If a key is defined in {@code CLOSURE_UNCOMPILED_DEFINES},
56 * {@code goog.define} will use the value instead of the default value. This
57 * allows flags to be overwritten without compilation (this is normally
58 * accomplished with the compiler's "define" flag).
59 *
60 * Example:
61 * <pre>
62 * var CLOSURE_UNCOMPILED_DEFINES = {'goog.DEBUG': false};
63 * </pre>
64 *
65 * @type {Object<string, (string|number|boolean)>|undefined}
66 */
67goog.global.CLOSURE_UNCOMPILED_DEFINES;
68
69
70/**
71 * A hook for overriding the define values in uncompiled or compiled mode,
72 * like CLOSURE_UNCOMPILED_DEFINES but effective in compiled code. In
73 * uncompiled code CLOSURE_UNCOMPILED_DEFINES takes precedence.
74 *
75 * Also unlike CLOSURE_UNCOMPILED_DEFINES the values must be number, boolean or
76 * string literals or the compiler will emit an error.
77 *
78 * While any @define value may be set, only those set with goog.define will be
79 * effective for uncompiled code.
80 *
81 * Example:
82 * <pre>
83 * var CLOSURE_DEFINES = {'goog.DEBUG': false} ;
84 * </pre>
85 *
86 * @type {Object<string, (string|number|boolean)>|undefined}
87 */
88goog.global.CLOSURE_DEFINES;
89
90
91/**
92 * Returns true if the specified value is not undefined.
93 * WARNING: Do not use this to test if an object has a property. Use the in
94 * operator instead.
95 *
96 * @param {?} val Variable to test.
97 * @return {boolean} Whether variable is defined.
98 */
99goog.isDef = function(val) {
100 // void 0 always evaluates to undefined and hence we do not need to depend on
101 // the definition of the global variable named 'undefined'.
102 return val !== void 0;
103};
104
105
106/**
107 * Builds an object structure for the provided namespace path, ensuring that
108 * names that already exist are not overwritten. For example:
109 * "a.b.c" -> a = {};a.b={};a.b.c={};
110 * Used by goog.provide and goog.exportSymbol.
111 * @param {string} name name of the object that this file defines.
112 * @param {*=} opt_object the object to expose at the end of the path.
113 * @param {Object=} opt_objectToExportTo The object to add the path to; default
114 * is |goog.global|.
115 * @private
116 */
117goog.exportPath_ = function(name, opt_object, opt_objectToExportTo) {
118 var parts = name.split('.');
119 var cur = opt_objectToExportTo || goog.global;
120
121 // Internet Explorer exhibits strange behavior when throwing errors from
122 // methods externed in this manner. See the testExportSymbolExceptions in
123 // base_test.html for an example.
124 if (!(parts[0] in cur) && cur.execScript) {
125 cur.execScript('var ' + parts[0]);
126 }
127
128 // Certain browsers cannot parse code in the form for((a in b); c;);
129 // This pattern is produced by the JSCompiler when it collapses the
130 // statement above into the conditional loop below. To prevent this from
131 // happening, use a for-loop and reserve the init logic as below.
132
133 // Parentheses added to eliminate strict JS warning in Firefox.
134 for (var part; parts.length && (part = parts.shift());) {
135 if (!parts.length && goog.isDef(opt_object)) {
136 // last part and we have an object; use it
137 cur[part] = opt_object;
138 } else if (cur[part]) {
139 cur = cur[part];
140 } else {
141 cur = cur[part] = {};
142 }
143 }
144};
145
146
147/**
148 * Defines a named value. In uncompiled mode, the value is retrieved from
149 * CLOSURE_DEFINES or CLOSURE_UNCOMPILED_DEFINES if the object is defined and
150 * has the property specified, and otherwise used the defined defaultValue.
151 * When compiled the default can be overridden using the compiler
152 * options or the value set in the CLOSURE_DEFINES object.
153 *
154 * @param {string} name The distinguished name to provide.
155 * @param {string|number|boolean} defaultValue
156 */
157goog.define = function(name, defaultValue) {
158 var value = defaultValue;
159 if (!COMPILED) {
160 if (goog.global.CLOSURE_UNCOMPILED_DEFINES &&
161 Object.prototype.hasOwnProperty.call(
162 goog.global.CLOSURE_UNCOMPILED_DEFINES, name)) {
163 value = goog.global.CLOSURE_UNCOMPILED_DEFINES[name];
164 } else if (goog.global.CLOSURE_DEFINES &&
165 Object.prototype.hasOwnProperty.call(
166 goog.global.CLOSURE_DEFINES, name)) {
167 value = goog.global.CLOSURE_DEFINES[name];
168 }
169 }
170 goog.exportPath_(name, value);
171};
172
173
174/**
175 * @define {boolean} DEBUG is provided as a convenience so that debugging code
176 * that should not be included in a production js_binary can be easily stripped
177 * by specifying --define goog.DEBUG=false to the JSCompiler. For example, most
178 * toString() methods should be declared inside an "if (goog.DEBUG)" conditional
179 * because they are generally used for debugging purposes and it is difficult
180 * for the JSCompiler to statically determine whether they are used.
181 */
182goog.define('goog.DEBUG', true);
183
184
185/**
186 * @define {string} LOCALE defines the locale being used for compilation. It is
187 * used to select locale specific data to be compiled in js binary. BUILD rule
188 * can specify this value by "--define goog.LOCALE=<locale_name>" as JSCompiler
189 * option.
190 *
191 * Take into account that the locale code format is important. You should use
192 * the canonical Unicode format with hyphen as a delimiter. Language must be
193 * lowercase, Language Script - Capitalized, Region - UPPERCASE.
194 * There are few examples: pt-BR, en, en-US, sr-Latin-BO, zh-Hans-CN.
195 *
196 * See more info about locale codes here:
197 * http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers
198 *
199 * For language codes you should use values defined by ISO 693-1. See it here
200 * http://www.w3.org/WAI/ER/IG/ert/iso639.htm. There is only one exception from
201 * this rule: the Hebrew language. For legacy reasons the old code (iw) should
202 * be used instead of the new code (he), see http://wiki/Main/IIISynonyms.
203 */
204goog.define('goog.LOCALE', 'en'); // default to en
205
206
207/**
208 * @define {boolean} Whether this code is running on trusted sites.
209 *
210 * On untrusted sites, several native functions can be defined or overridden by
211 * external libraries like Prototype, Datejs, and JQuery and setting this flag
212 * to false forces closure to use its own implementations when possible.
213 *
214 * If your JavaScript can be loaded by a third party site and you are wary about
215 * relying on non-standard implementations, specify
216 * "--define goog.TRUSTED_SITE=false" to the JSCompiler.
217 */
218goog.define('goog.TRUSTED_SITE', true);
219
220
221/**
222 * @define {boolean} Whether a project is expected to be running in strict mode.
223 *
224 * This define can be used to trigger alternate implementations compatible with
225 * running in EcmaScript Strict mode or warn about unavailable functionality.
226 * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope/Strict_mode
227 *
228 */
229goog.define('goog.STRICT_MODE_COMPATIBLE', false);
230
231
232/**
233 * @define {boolean} Whether code that calls {@link goog.setTestOnly} should
234 * be disallowed in the compilation unit.
235 */
236goog.define('goog.DISALLOW_TEST_ONLY_CODE', COMPILED && !goog.DEBUG);
237
238
239/**
240 * @define {boolean} Whether to use a Chrome app CSP-compliant method for
241 * loading scripts via goog.require. @see appendScriptSrcNode_.
242 */
243goog.define('goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING', false);
244
245
246/**
247 * Defines a namespace in Closure.
248 *
249 * A namespace may only be defined once in a codebase. It may be defined using
250 * goog.provide() or goog.module().
251 *
252 * The presence of one or more goog.provide() calls in a file indicates
253 * that the file defines the given objects/namespaces.
254 * Provided symbols must not be null or undefined.
255 *
256 * In addition, goog.provide() creates the object stubs for a namespace
257 * (for example, goog.provide("goog.foo.bar") will create the object
258 * goog.foo.bar if it does not already exist).
259 *
260 * Build tools also scan for provide/require/module statements
261 * to discern dependencies, build dependency files (see deps.js), etc.
262 *
263 * @see goog.require
264 * @see goog.module
265 * @param {string} name Namespace provided by this file in the form
266 * "goog.package.part".
267 */
268goog.provide = function(name) {
269 if (!COMPILED) {
270 // Ensure that the same namespace isn't provided twice.
271 // A goog.module/goog.provide maps a goog.require to a specific file
272 if (goog.isProvided_(name)) {
273 throw Error('Namespace "' + name + '" already declared.');
274 }
275 }
276
277 goog.constructNamespace_(name);
278};
279
280
281/**
282 * @param {string} name Namespace provided by this file in the form
283 * "goog.package.part".
284 * @param {Object=} opt_obj The object to embed in the namespace.
285 * @private
286 */
287goog.constructNamespace_ = function(name, opt_obj) {
288 if (!COMPILED) {
289 delete goog.implicitNamespaces_[name];
290
291 var namespace = name;
292 while ((namespace = namespace.substring(0, namespace.lastIndexOf('.')))) {
293 if (goog.getObjectByName(namespace)) {
294 break;
295 }
296 goog.implicitNamespaces_[namespace] = true;
297 }
298 }
299
300 goog.exportPath_(name, opt_obj);
301};
302
303
304/**
305 * Module identifier validation regexp.
306 * Note: This is a conservative check, it is very possible to be more lenient,
307 * the primary exclusion here is "/" and "\" and a leading ".", these
308 * restrictions are intended to leave the door open for using goog.require
309 * with relative file paths rather than module identifiers.
310 * @private
311 */
312goog.VALID_MODULE_RE_ = /^[a-zA-Z_$][a-zA-Z0-9._$]*$/;
313
314
315/**
316 * Defines a module in Closure.
317 *
318 * Marks that this file must be loaded as a module and claims the namespace.
319 *
320 * A namespace may only be defined once in a codebase. It may be defined using
321 * goog.provide() or goog.module().
322 *
323 * goog.module() has three requirements:
324 * - goog.module may not be used in the same file as goog.provide.
325 * - goog.module must be the first statement in the file.
326 * - only one goog.module is allowed per file.
327 *
328 * When a goog.module annotated file is loaded, it is enclosed in
329 * a strict function closure. This means that:
330 * - any variables declared in a goog.module file are private to the file
331 * (not global), though the compiler is expected to inline the module.
332 * - The code must obey all the rules of "strict" JavaScript.
333 * - the file will be marked as "use strict"
334 *
335 * NOTE: unlike goog.provide, goog.module does not declare any symbols by
336 * itself. If declared symbols are desired, use
337 * goog.module.declareLegacyNamespace().
338 *
339 *
340 * See the public goog.module proposal: http://goo.gl/Va1hin
341 *
342 * @param {string} name Namespace provided by this file in the form
343 * "goog.package.part", is expected but not required.
344 */
345goog.module = function(name) {
346 if (!goog.isString(name) ||
347 !name ||
348 name.search(goog.VALID_MODULE_RE_) == -1) {
349 throw Error('Invalid module identifier');
350 }
351 if (!goog.isInModuleLoader_()) {
352 throw Error('Module ' + name + ' has been loaded incorrectly.');
353 }
354 if (goog.moduleLoaderState_.moduleName) {
355 throw Error('goog.module may only be called once per module.');
356 }
357
358 // Store the module name for the loader.
359 goog.moduleLoaderState_.moduleName = name;
360 if (!COMPILED) {
361 // Ensure that the same namespace isn't provided twice.
362 // A goog.module/goog.provide maps a goog.require to a specific file
363 if (goog.isProvided_(name)) {
364 throw Error('Namespace "' + name + '" already declared.');
365 }
366 delete goog.implicitNamespaces_[name];
367 }
368};
369
370
371/**
372 * @param {string} name The module identifier.
373 * @return {?} The module exports for an already loaded module or null.
374 *
375 * Note: This is not an alternative to goog.require, it does not
376 * indicate a hard dependency, instead it is used to indicate
377 * an optional dependency or to access the exports of a module
378 * that has already been loaded.
379 * @suppress {missingProvide}
380 */
381goog.module.get = function(name) {
382 return goog.module.getInternal_(name);
383};
384
385
386/**
387 * @param {string} name The module identifier.
388 * @return {?} The module exports for an already loaded module or null.
389 * @private
390 */
391goog.module.getInternal_ = function(name) {
392 if (!COMPILED) {
393 if (goog.isProvided_(name)) {
394 // goog.require only return a value with-in goog.module files.
395 return name in goog.loadedModules_ ?
396 goog.loadedModules_[name] :
397 goog.getObjectByName(name);
398 } else {
399 return null;
400 }
401 }
402};
403
404
405/**
406 * @private {?{moduleName: (string|undefined), declareLegacyNamespace:boolean}}
407 */
408goog.moduleLoaderState_ = null;
409
410
411/**
412 * @private
413 * @return {boolean} Whether a goog.module is currently being initialized.
414 */
415goog.isInModuleLoader_ = function() {
416 return goog.moduleLoaderState_ != null;
417};
418
419
420/**
421 * Provide the module's exports as a globally accessible object under the
422 * module's declared name. This is intended to ease migration to goog.module
423 * for files that have existing usages.
424 * @suppress {missingProvide}
425 */
426goog.module.declareLegacyNamespace = function() {
427 if (!COMPILED && !goog.isInModuleLoader_()) {
428 throw new Error('goog.module.declareLegacyNamespace must be called from ' +
429 'within a goog.module');
430 }
431 if (!COMPILED && !goog.moduleLoaderState_.moduleName) {
432 throw Error('goog.module must be called prior to ' +
433 'goog.module.declareLegacyNamespace.');
434 }
435 goog.moduleLoaderState_.declareLegacyNamespace = true;
436};
437
438
439/**
440 * Marks that the current file should only be used for testing, and never for
441 * live code in production.
442 *
443 * In the case of unit tests, the message may optionally be an exact namespace
444 * for the test (e.g. 'goog.stringTest'). The linter will then ignore the extra
445 * provide (if not explicitly defined in the code).
446 *
447 * @param {string=} opt_message Optional message to add to the error that's
448 * raised when used in production code.
449 */
450goog.setTestOnly = function(opt_message) {
451 if (goog.DISALLOW_TEST_ONLY_CODE) {
452 opt_message = opt_message || '';
453 throw Error('Importing test-only code into non-debug environment' +
454 (opt_message ? ': ' + opt_message : '.'));
455 }
456};
457
458
459/**
460 * Forward declares a symbol. This is an indication to the compiler that the
461 * symbol may be used in the source yet is not required and may not be provided
462 * in compilation.
463 *
464 * The most common usage of forward declaration is code that takes a type as a
465 * function parameter but does not need to require it. By forward declaring
466 * instead of requiring, no hard dependency is made, and (if not required
467 * elsewhere) the namespace may never be required and thus, not be pulled
468 * into the JavaScript binary. If it is required elsewhere, it will be type
469 * checked as normal.
470 *
471 *
472 * @param {string} name The namespace to forward declare in the form of
473 * "goog.package.part".
474 */
475goog.forwardDeclare = function(name) {};
476
477
478/**
479 * Forward declare type information. Used to assign types to goog.global
480 * referenced object that would otherwise result in unknown type references
481 * and thus block property disambiguation.
482 */
483goog.forwardDeclare('Document');
484goog.forwardDeclare('HTMLScriptElement');
485goog.forwardDeclare('XMLHttpRequest');
486
487
488if (!COMPILED) {
489
490 /**
491 * Check if the given name has been goog.provided. This will return false for
492 * names that are available only as implicit namespaces.
493 * @param {string} name name of the object to look for.
494 * @return {boolean} Whether the name has been provided.
495 * @private
496 */
497 goog.isProvided_ = function(name) {
498 return (name in goog.loadedModules_) ||
499 (!goog.implicitNamespaces_[name] &&
500 goog.isDefAndNotNull(goog.getObjectByName(name)));
501 };
502
503 /**
504 * Namespaces implicitly defined by goog.provide. For example,
505 * goog.provide('goog.events.Event') implicitly declares that 'goog' and
506 * 'goog.events' must be namespaces.
507 *
508 * @type {!Object<string, (boolean|undefined)>}
509 * @private
510 */
511 goog.implicitNamespaces_ = {'goog.module': true};
512
513 // NOTE: We add goog.module as an implicit namespace as goog.module is defined
514 // here and because the existing module package has not been moved yet out of
515 // the goog.module namespace. This satisifies both the debug loader and
516 // ahead-of-time dependency management.
517}
518
519
520/**
521 * Returns an object based on its fully qualified external name. The object
522 * is not found if null or undefined. If you are using a compilation pass that
523 * renames property names beware that using this function will not find renamed
524 * properties.
525 *
526 * @param {string} name The fully qualified name.
527 * @param {Object=} opt_obj The object within which to look; default is
528 * |goog.global|.
529 * @return {?} The value (object or primitive) or, if not found, null.
530 */
531goog.getObjectByName = function(name, opt_obj) {
532 var parts = name.split('.');
533 var cur = opt_obj || goog.global;
534 for (var part; part = parts.shift(); ) {
535 if (goog.isDefAndNotNull(cur[part])) {
536 cur = cur[part];
537 } else {
538 return null;
539 }
540 }
541 return cur;
542};
543
544
545/**
546 * Globalizes a whole namespace, such as goog or goog.lang.
547 *
548 * @param {!Object} obj The namespace to globalize.
549 * @param {Object=} opt_global The object to add the properties to.
550 * @deprecated Properties may be explicitly exported to the global scope, but
551 * this should no longer be done in bulk.
552 */
553goog.globalize = function(obj, opt_global) {
554 var global = opt_global || goog.global;
555 for (var x in obj) {
556 global[x] = obj[x];
557 }
558};
559
560
561/**
562 * Adds a dependency from a file to the files it requires.
563 * @param {string} relPath The path to the js file.
564 * @param {!Array<string>} provides An array of strings with
565 * the names of the objects this file provides.
566 * @param {!Array<string>} requires An array of strings with
567 * the names of the objects this file requires.
568 * @param {boolean=} opt_isModule Whether this dependency must be loaded as
569 * a module as declared by goog.module.
570 */
571goog.addDependency = function(relPath, provides, requires, opt_isModule) {
572 if (goog.DEPENDENCIES_ENABLED) {
573 var provide, require;
574 var path = relPath.replace(/\\/g, '/');
575 var deps = goog.dependencies_;
576 for (var i = 0; provide = provides[i]; i++) {
577 deps.nameToPath[provide] = path;
578 deps.pathIsModule[path] = !!opt_isModule;
579 }
580 for (var j = 0; require = requires[j]; j++) {
581 if (!(path in deps.requires)) {
582 deps.requires[path] = {};
583 }
584 deps.requires[path][require] = true;
585 }
586 }
587};
588
589
590
591
592// NOTE(nnaze): The debug DOM loader was included in base.js as an original way
593// to do "debug-mode" development. The dependency system can sometimes be
594// confusing, as can the debug DOM loader's asynchronous nature.
595//
596// With the DOM loader, a call to goog.require() is not blocking -- the script
597// will not load until some point after the current script. If a namespace is
598// needed at runtime, it needs to be defined in a previous script, or loaded via
599// require() with its registered dependencies.
600// User-defined namespaces may need their own deps file. See http://go/js_deps,
601// http://go/genjsdeps, or, externally, DepsWriter.
602// https://developers.google.com/closure/library/docs/depswriter
603//
604// Because of legacy clients, the DOM loader can't be easily removed from
605// base.js. Work is being done to make it disableable or replaceable for
606// different environments (DOM-less JavaScript interpreters like Rhino or V8,
607// for example). See bootstrap/ for more information.
608
609
610/**
611 * @define {boolean} Whether to enable the debug loader.
612 *
613 * If enabled, a call to goog.require() will attempt to load the namespace by
614 * appending a script tag to the DOM (if the namespace has been registered).
615 *
616 * If disabled, goog.require() will simply assert that the namespace has been
617 * provided (and depend on the fact that some outside tool correctly ordered
618 * the script).
619 */
620goog.define('goog.ENABLE_DEBUG_LOADER', true);
621
622
623/**
624 * @param {string} msg
625 * @private
626 */
627goog.logToConsole_ = function(msg) {
628 if (goog.global.console) {
629 goog.global.console['error'](msg);
630 }
631};
632
633
634/**
635 * Implements a system for the dynamic resolution of dependencies that works in
636 * parallel with the BUILD system. Note that all calls to goog.require will be
637 * stripped by the JSCompiler when the --process_closure_primitives option is
638 * used.
639 * @see goog.provide
640 * @param {string} name Namespace to include (as was given in goog.provide()) in
641 * the form "goog.package.part".
642 * @return {?} If called within a goog.module file, the associated namespace or
643 * module otherwise null.
644 */
645goog.require = function(name) {
646 // If the object already exists we do not need do do anything.
647 if (!COMPILED) {
648 if (goog.ENABLE_DEBUG_LOADER && goog.IS_OLD_IE_) {
649 goog.maybeProcessDeferredDep_(name);
650 }
651
652 if (goog.isProvided_(name)) {
653 if (goog.isInModuleLoader_()) {
654 return goog.module.getInternal_(name);
655 } else {
656 return null;
657 }
658 }
659
660 if (goog.ENABLE_DEBUG_LOADER) {
661 var path = goog.getPathFromDeps_(name);
662 if (path) {
663 goog.writeScripts_(path);
664 return null;
665 }
666 }
667
668 var errorMessage = 'goog.require could not find: ' + name;
669 goog.logToConsole_(errorMessage);
670
671 throw Error(errorMessage);
672 }
673};
674
675
676/**
677 * Path for included scripts.
678 * @type {string}
679 */
680goog.basePath = '';
681
682
683/**
684 * A hook for overriding the base path.
685 * @type {string|undefined}
686 */
687goog.global.CLOSURE_BASE_PATH;
688
689
690/**
691 * Whether to write out Closure's deps file. By default, the deps are written.
692 * @type {boolean|undefined}
693 */
694goog.global.CLOSURE_NO_DEPS;
695
696
697/**
698 * A function to import a single script. This is meant to be overridden when
699 * Closure is being run in non-HTML contexts, such as web workers. It's defined
700 * in the global scope so that it can be set before base.js is loaded, which
701 * allows deps.js to be imported properly.
702 *
703 * The function is passed the script source, which is a relative URI. It should
704 * return true if the script was imported, false otherwise.
705 * @type {(function(string): boolean)|undefined}
706 */
707goog.global.CLOSURE_IMPORT_SCRIPT;
708
709
710/**
711 * Null function used for default values of callbacks, etc.
712 * @return {void} Nothing.
713 */
714goog.nullFunction = function() {};
715
716
717/**
718 * When defining a class Foo with an abstract method bar(), you can do:
719 * Foo.prototype.bar = goog.abstractMethod
720 *
721 * Now if a subclass of Foo fails to override bar(), an error will be thrown
722 * when bar() is invoked.
723 *
724 * Note: This does not take the name of the function to override as an argument
725 * because that would make it more difficult to obfuscate our JavaScript code.
726 *
727 * @type {!Function}
728 * @throws {Error} when invoked to indicate the method should be overridden.
729 */
730goog.abstractMethod = function() {
731 throw Error('unimplemented abstract method');
732};
733
734
735/**
736 * Adds a {@code getInstance} static method that always returns the same
737 * instance object.
738 * @param {!Function} ctor The constructor for the class to add the static
739 * method to.
740 */
741goog.addSingletonGetter = function(ctor) {
742 ctor.getInstance = function() {
743 if (ctor.instance_) {
744 return ctor.instance_;
745 }
746 if (goog.DEBUG) {
747 // NOTE: JSCompiler can't optimize away Array#push.
748 goog.instantiatedSingletons_[goog.instantiatedSingletons_.length] = ctor;
749 }
750 return ctor.instance_ = new ctor;
751 };
752};
753
754
755/**
756 * All singleton classes that have been instantiated, for testing. Don't read
757 * it directly, use the {@code goog.testing.singleton} module. The compiler
758 * removes this variable if unused.
759 * @type {!Array<!Function>}
760 * @private
761 */
762goog.instantiatedSingletons_ = [];
763
764
765/**
766 * @define {boolean} Whether to load goog.modules using {@code eval} when using
767 * the debug loader. This provides a better debugging experience as the
768 * source is unmodified and can be edited using Chrome Workspaces or similar.
769 * However in some environments the use of {@code eval} is banned
770 * so we provide an alternative.
771 */
772goog.define('goog.LOAD_MODULE_USING_EVAL', true);
773
774
775/**
776 * @define {boolean} Whether the exports of goog.modules should be sealed when
777 * possible.
778 */
779goog.define('goog.SEAL_MODULE_EXPORTS', goog.DEBUG);
780
781
782/**
783 * The registry of initialized modules:
784 * the module identifier to module exports map.
785 * @private @const {!Object<string, ?>}
786 */
787goog.loadedModules_ = {};
788
789
790/**
791 * True if goog.dependencies_ is available.
792 * @const {boolean}
793 */
794goog.DEPENDENCIES_ENABLED = !COMPILED && goog.ENABLE_DEBUG_LOADER;
795
796
797if (goog.DEPENDENCIES_ENABLED) {
798
799 /**
800 * This object is used to keep track of dependencies and other data that is
801 * used for loading scripts.
802 * @private
803 * @type {{
804 * pathIsModule: !Object<string, boolean>,
805 * nameToPath: !Object<string, string>,
806 * requires: !Object<string, !Object<string, boolean>>,
807 * visited: !Object<string, boolean>,
808 * written: !Object<string, boolean>,
809 * deferred: !Object<string, string>
810 * }}
811 */
812 goog.dependencies_ = {
813 pathIsModule: {}, // 1 to 1
814
815 nameToPath: {}, // 1 to 1
816
817 requires: {}, // 1 to many
818
819 // Used when resolving dependencies to prevent us from visiting file twice.
820 visited: {},
821
822 written: {}, // Used to keep track of script files we have written.
823
824 deferred: {} // Used to track deferred module evaluations in old IEs
825 };
826
827
828 /**
829 * Tries to detect whether is in the context of an HTML document.
830 * @return {boolean} True if it looks like HTML document.
831 * @private
832 */
833 goog.inHtmlDocument_ = function() {
834 /** @type {Document} */
835 var doc = goog.global.document;
836 return doc != null && 'write' in doc; // XULDocument misses write.
837 };
838
839
840 /**
841 * Tries to detect the base path of base.js script that bootstraps Closure.
842 * @private
843 */
844 goog.findBasePath_ = function() {
845 if (goog.isDef(goog.global.CLOSURE_BASE_PATH)) {
846 goog.basePath = goog.global.CLOSURE_BASE_PATH;
847 return;
848 } else if (!goog.inHtmlDocument_()) {
849 return;
850 }
851 /** @type {Document} */
852 var doc = goog.global.document;
853 var scripts = doc.getElementsByTagName('SCRIPT');
854 // Search backwards since the current script is in almost all cases the one
855 // that has base.js.
856 for (var i = scripts.length - 1; i >= 0; --i) {
857 var script = /** @type {!HTMLScriptElement} */ (scripts[i]);
858 var src = script.src;
859 var qmark = src.lastIndexOf('?');
860 var l = qmark == -1 ? src.length : qmark;
861 if (src.substr(l - 7, 7) == 'base.js') {
862 goog.basePath = src.substr(0, l - 7);
863 return;
864 }
865 }
866 };
867
868
869 /**
870 * Imports a script if, and only if, that script hasn't already been imported.
871 * (Must be called at execution time)
872 * @param {string} src Script source.
873 * @param {string=} opt_sourceText The optionally source text to evaluate
874 * @private
875 */
876 goog.importScript_ = function(src, opt_sourceText) {
877 var importScript = goog.global.CLOSURE_IMPORT_SCRIPT ||
878 goog.writeScriptTag_;
879 if (importScript(src, opt_sourceText)) {
880 goog.dependencies_.written[src] = true;
881 }
882 };
883
884
885 /** @const @private {boolean} */
886 goog.IS_OLD_IE_ = !!(!goog.global.atob && goog.global.document &&
887 goog.global.document.all);
888
889
890 /**
891 * Given a URL initiate retrieval and execution of the module.
892 * @param {string} src Script source URL.
893 * @private
894 */
895 goog.importModule_ = function(src) {
896 // In an attempt to keep browsers from timing out loading scripts using
897 // synchronous XHRs, put each load in its own script block.
898 var bootstrap = 'goog.retrieveAndExecModule_("' + src + '");';
899
900 if (goog.importScript_('', bootstrap)) {
901 goog.dependencies_.written[src] = true;
902 }
903 };
904
905
906 /** @private {!Array<string>} */
907 goog.queuedModules_ = [];
908
909
910 /**
911 * Return an appropriate module text. Suitable to insert into
912 * a script tag (that is unescaped).
913 * @param {string} srcUrl
914 * @param {string} scriptText
915 * @return {string}
916 * @private
917 */
918 goog.wrapModule_ = function(srcUrl, scriptText) {
919 if (!goog.LOAD_MODULE_USING_EVAL || !goog.isDef(goog.global.JSON)) {
920 return '' +
921 'goog.loadModule(function(exports) {' +
922 '"use strict";' +
923 scriptText +
924 '\n' + // terminate any trailing single line comment.
925 ';return exports' +
926 '});' +
927 '\n//# sourceURL=' + srcUrl + '\n';
928 } else {
929 return '' +
930 'goog.loadModule(' +
931 goog.global.JSON.stringify(
932 scriptText + '\n//# sourceURL=' + srcUrl + '\n') +
933 ');';
934 }
935 };
936
937 // On IE9 and earlier, it is necessary to handle
938 // deferred module loads. In later browsers, the
939 // code to be evaluated is simply inserted as a script
940 // block in the correct order. To eval deferred
941 // code at the right time, we piggy back on goog.require to call
942 // goog.maybeProcessDeferredDep_.
943 //
944 // The goog.requires are used both to bootstrap
945 // the loading process (when no deps are available) and
946 // declare that they should be available.
947 //
948 // Here we eval the sources, if all the deps are available
949 // either already eval'd or goog.require'd. This will
950 // be the case when all the dependencies have already
951 // been loaded, and the dependent module is loaded.
952 //
953 // But this alone isn't sufficient because it is also
954 // necessary to handle the case where there is no root
955 // that is not deferred. For that there we register for an event
956 // and trigger goog.loadQueuedModules_ handle any remaining deferred
957 // evaluations.
958
959 /**
960 * Handle any remaining deferred goog.module evals.
961 * @private
962 */
963 goog.loadQueuedModules_ = function() {
964 var count = goog.queuedModules_.length;
965 if (count > 0) {
966 var queue = goog.queuedModules_;
967 goog.queuedModules_ = [];
968 for (var i = 0; i < count; i++) {
969 var path = queue[i];
970 goog.maybeProcessDeferredPath_(path);
971 }
972 }
973 };
974
975
976 /**
977 * Eval the named module if its dependencies are
978 * available.
979 * @param {string} name The module to load.
980 * @private
981 */
982 goog.maybeProcessDeferredDep_ = function(name) {
983 if (goog.isDeferredModule_(name) &&
984 goog.allDepsAreAvailable_(name)) {
985 var path = goog.getPathFromDeps_(name);
986 goog.maybeProcessDeferredPath_(goog.basePath + path);
987 }
988 };
989
990 /**
991 * @param {string} name The module to check.
992 * @return {boolean} Whether the name represents a
993 * module whose evaluation has been deferred.
994 * @private
995 */
996 goog.isDeferredModule_ = function(name) {
997 var path = goog.getPathFromDeps_(name);
998 if (path && goog.dependencies_.pathIsModule[path]) {
999 var abspath = goog.basePath + path;
1000 return (abspath) in goog.dependencies_.deferred;
1001 }
1002 return false;
1003 };
1004
1005 /**
1006 * @param {string} name The module to check.
1007 * @return {boolean} Whether the name represents a
1008 * module whose declared dependencies have all been loaded
1009 * (eval'd or a deferred module load)
1010 * @private
1011 */
1012 goog.allDepsAreAvailable_ = function(name) {
1013 var path = goog.getPathFromDeps_(name);
1014 if (path && (path in goog.dependencies_.requires)) {
1015 for (var requireName in goog.dependencies_.requires[path]) {
1016 if (!goog.isProvided_(requireName) &&
1017 !goog.isDeferredModule_(requireName)) {
1018 return false;
1019 }
1020 }
1021 }
1022 return true;
1023 };
1024
1025
1026 /**
1027 * @param {string} abspath
1028 * @private
1029 */
1030 goog.maybeProcessDeferredPath_ = function(abspath) {
1031 if (abspath in goog.dependencies_.deferred) {
1032 var src = goog.dependencies_.deferred[abspath];
1033 delete goog.dependencies_.deferred[abspath];
1034 goog.globalEval(src);
1035 }
1036 };
1037
1038
1039 /**
1040 * Load a goog.module from the provided URL. This is not a general purpose
1041 * code loader and does not support late loading code, that is it should only
1042 * be used during page load. This method exists to support unit tests and
1043 * "debug" loaders that would otherwise have inserted script tags. Under the
1044 * hood this needs to use a synchronous XHR and is not recommeneded for
1045 * production code.
1046 *
1047 * The module's goog.requires must have already been satisified; an exception
1048 * will be thrown if this is not the case. This assumption is that no
1049 * "deps.js" file exists, so there is no way to discover and locate the
1050 * module-to-be-loaded's dependencies and no attempt is made to do so.
1051 *
1052 * There should only be one attempt to load a module. If
1053 * "goog.loadModuleFromUrl" is called for an already loaded module, an
1054 * exception will be throw.
1055 *
1056 * @param {string} url The URL from which to attempt to load the goog.module.
1057 */
1058 goog.loadModuleFromUrl = function(url) {
1059 // Because this executes synchronously, we don't need to do any additional
1060 // bookkeeping. When "goog.loadModule" the namespace will be marked as
1061 // having been provided which is sufficient.
1062 goog.retrieveAndExecModule_(url);
1063 };
1064
1065
1066 /**
1067 * @param {function(?):?|string} moduleDef The module definition.
1068 */
1069 goog.loadModule = function(moduleDef) {
1070 // NOTE: we allow function definitions to be either in the from
1071 // of a string to eval (which keeps the original source intact) or
1072 // in a eval forbidden environment (CSP) we allow a function definition
1073 // which in its body must call {@code goog.module}, and return the exports
1074 // of the module.
1075 var previousState = goog.moduleLoaderState_;
1076 try {
1077 goog.moduleLoaderState_ = {
1078 moduleName: undefined,
1079 declareLegacyNamespace: false
1080 };
1081 var exports;
1082 if (goog.isFunction(moduleDef)) {
1083 exports = moduleDef.call(goog.global, {});
1084 } else if (goog.isString(moduleDef)) {
1085 exports = goog.loadModuleFromSource_.call(goog.global, moduleDef);
1086 } else {
1087 throw Error('Invalid module definition');
1088 }
1089
1090 var moduleName = goog.moduleLoaderState_.moduleName;
1091 if (!goog.isString(moduleName) || !moduleName) {
1092 throw Error('Invalid module name \"' + moduleName + '\"');
1093 }
1094
1095 // Don't seal legacy namespaces as they may be uses as a parent of
1096 // another namespace
1097 if (goog.moduleLoaderState_.declareLegacyNamespace) {
1098 goog.constructNamespace_(moduleName, exports);
1099 } else if (goog.SEAL_MODULE_EXPORTS && Object.seal) {
1100 Object.seal(exports);
1101 }
1102
1103 goog.loadedModules_[moduleName] = exports;
1104 } finally {
1105 goog.moduleLoaderState_ = previousState;
1106 }
1107 };
1108
1109
1110 /**
1111 * @private @const {function(string):?}
1112 *
1113 * The new type inference warns because this function has no formal
1114 * parameters, but its jsdoc says that it takes one argument.
1115 * (The argument is used via arguments[0], but NTI does not detect this.)
1116 * @suppress {newCheckTypes}
1117 */
1118 goog.loadModuleFromSource_ = function() {
1119 // NOTE: we avoid declaring parameters or local variables here to avoid
1120 // masking globals or leaking values into the module definition.
1121 'use strict';
1122 var exports = {};
1123 eval(arguments[0]);
1124 return exports;
1125 };
1126
1127
1128 /**
1129 * Writes a new script pointing to {@code src} directly into the DOM.
1130 *
1131 * NOTE: This method is not CSP-compliant. @see goog.appendScriptSrcNode_ for
1132 * the fallback mechanism.
1133 *
1134 * @param {string} src The script URL.
1135 * @private
1136 */
1137 goog.writeScriptSrcNode_ = function(src) {
1138 goog.global.document.write(
1139 '<script type="text/javascript" src="' + src + '"></' + 'script>');
1140 };
1141
1142
1143 /**
1144 * Appends a new script node to the DOM using a CSP-compliant mechanism. This
1145 * method exists as a fallback for document.write (which is not allowed in a
1146 * strict CSP context, e.g., Chrome apps).
1147 *
1148 * NOTE: This method is not analogous to using document.write to insert a
1149 * <script> tag; specifically, the user agent will execute a script added by
1150 * document.write immediately after the current script block finishes
1151 * executing, whereas the DOM-appended script node will not be executed until
1152 * the entire document is parsed and executed. That is to say, this script is
1153 * added to the end of the script execution queue.
1154 *
1155 * The page must not attempt to call goog.required entities until after the
1156 * document has loaded, e.g., in or after the window.onload callback.
1157 *
1158 * @param {string} src The script URL.
1159 * @private
1160 */
1161 goog.appendScriptSrcNode_ = function(src) {
1162 /** @type {Document} */
1163 var doc = goog.global.document;
1164 var scriptEl = /** @type {HTMLScriptElement} */ (
1165 doc.createElement('script'));
1166 scriptEl.type = 'text/javascript';
1167 scriptEl.src = src;
1168 scriptEl.defer = false;
1169 scriptEl.async = false;
1170 doc.head.appendChild(scriptEl);
1171 };
1172
1173
1174 /**
1175 * The default implementation of the import function. Writes a script tag to
1176 * import the script.
1177 *
1178 * @param {string} src The script url.
1179 * @param {string=} opt_sourceText The optionally source text to evaluate
1180 * @return {boolean} True if the script was imported, false otherwise.
1181 * @private
1182 */
1183 goog.writeScriptTag_ = function(src, opt_sourceText) {
1184 if (goog.inHtmlDocument_()) {
1185 /** @type {Document} */
1186 var doc = goog.global.document;
1187
1188 // If the user tries to require a new symbol after document load,
1189 // something has gone terribly wrong. Doing a document.write would
1190 // wipe out the page. This does not apply to the CSP-compliant method
1191 // of writing script tags.
1192 if (!goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING &&
1193 doc.readyState == 'complete') {
1194 // Certain test frameworks load base.js multiple times, which tries
1195 // to write deps.js each time. If that happens, just fail silently.
1196 // These frameworks wipe the page between each load of base.js, so this
1197 // is OK.
1198 var isDeps = /\bdeps.js$/.test(src);
1199 if (isDeps) {
1200 return false;
1201 } else {
1202 throw Error('Cannot write "' + src + '" after document load');
1203 }
1204 }
1205
1206 var isOldIE = goog.IS_OLD_IE_;
1207
1208 if (opt_sourceText === undefined) {
1209 if (!isOldIE) {
1210 if (goog.ENABLE_CHROME_APP_SAFE_SCRIPT_LOADING) {
1211 goog.appendScriptSrcNode_(src);
1212 } else {
1213 goog.writeScriptSrcNode_(src);
1214 }
1215 } else {
1216 var state = " onreadystatechange='goog.onScriptLoad_(this, " +
1217 ++goog.lastNonModuleScriptIndex_ + ")' ";
1218 doc.write(
1219 '<script type="text/javascript" src="' +
1220 src + '"' + state + '></' + 'script>');
1221 }
1222 } else {
1223 doc.write(
1224 '<script type="text/javascript">' +
1225 opt_sourceText +
1226 '</' + 'script>');
1227 }
1228 return true;
1229 } else {
1230 return false;
1231 }
1232 };
1233
1234
1235 /** @private {number} */
1236 goog.lastNonModuleScriptIndex_ = 0;
1237
1238
1239 /**
1240 * A readystatechange handler for legacy IE
1241 * @param {!HTMLScriptElement} script
1242 * @param {number} scriptIndex
1243 * @return {boolean}
1244 * @private
1245 */
1246 goog.onScriptLoad_ = function(script, scriptIndex) {
1247 // for now load the modules when we reach the last script,
1248 // later allow more inter-mingling.
1249 if (script.readyState == 'complete' &&
1250 goog.lastNonModuleScriptIndex_ == scriptIndex) {
1251 goog.loadQueuedModules_();
1252 }
1253 return true;
1254 };
1255
1256 /**
1257 * Resolves dependencies based on the dependencies added using addDependency
1258 * and calls importScript_ in the correct order.
1259 * @param {string} pathToLoad The path from which to start discovering
1260 * dependencies.
1261 * @private
1262 */
1263 goog.writeScripts_ = function(pathToLoad) {
1264 /** @type {!Array<string>} The scripts we need to write this time. */
1265 var scripts = [];
1266 var seenScript = {};
1267 var deps = goog.dependencies_;
1268
1269 /** @param {string} path */
1270 function visitNode(path) {
1271 if (path in deps.written) {
1272 return;
1273 }
1274
1275 // We have already visited this one. We can get here if we have cyclic
1276 // dependencies.
1277 if (path in deps.visited) {
1278 return;
1279 }
1280
1281 deps.visited[path] = true;
1282
1283 if (path in deps.requires) {
1284 for (var requireName in deps.requires[path]) {
1285 // If the required name is defined, we assume that it was already
1286 // bootstrapped by other means.
1287 if (!goog.isProvided_(requireName)) {
1288 if (requireName in deps.nameToPath) {
1289 visitNode(deps.nameToPath[requireName]);
1290 } else {
1291 throw Error('Undefined nameToPath for ' + requireName);
1292 }
1293 }
1294 }
1295 }
1296
1297 if (!(path in seenScript)) {
1298 seenScript[path] = true;
1299 scripts.push(path);
1300 }
1301 }
1302
1303 visitNode(pathToLoad);
1304
1305 // record that we are going to load all these scripts.
1306 for (var i = 0; i < scripts.length; i++) {
1307 var path = scripts[i];
1308 goog.dependencies_.written[path] = true;
1309 }
1310
1311 // If a module is loaded synchronously then we need to
1312 // clear the current inModuleLoader value, and restore it when we are
1313 // done loading the current "requires".
1314 var moduleState = goog.moduleLoaderState_;
1315 goog.moduleLoaderState_ = null;
1316
1317 for (var i = 0; i < scripts.length; i++) {
1318 var path = scripts[i];
1319 if (path) {
1320 if (!deps.pathIsModule[path]) {
1321 goog.importScript_(goog.basePath + path);
1322 } else {
1323 goog.importModule_(goog.basePath + path);
1324 }
1325 } else {
1326 goog.moduleLoaderState_ = moduleState;
1327 throw Error('Undefined script input');
1328 }
1329 }
1330
1331 // restore the current "module loading state"
1332 goog.moduleLoaderState_ = moduleState;
1333 };
1334
1335
1336 /**
1337 * Looks at the dependency rules and tries to determine the script file that
1338 * fulfills a particular rule.
1339 * @param {string} rule In the form goog.namespace.Class or project.script.
1340 * @return {?string} Url corresponding to the rule, or null.
1341 * @private
1342 */
1343 goog.getPathFromDeps_ = function(rule) {
1344 if (rule in goog.dependencies_.nameToPath) {
1345 return goog.dependencies_.nameToPath[rule];
1346 } else {
1347 return null;
1348 }
1349 };
1350
1351 goog.findBasePath_();
1352
1353 // Allow projects to manage the deps files themselves.
1354 if (!goog.global.CLOSURE_NO_DEPS) {
1355 goog.importScript_(goog.basePath + 'deps.js');
1356 }
1357}
1358
1359
1360/**
1361 * Normalize a file path by removing redundant ".." and extraneous "." file
1362 * path components.
1363 * @param {string} path
1364 * @return {string}
1365 * @private
1366 */
1367goog.normalizePath_ = function(path) {
1368 var components = path.split('/');
1369 var i = 0;
1370 while (i < components.length) {
1371 if (components[i] == '.') {
1372 components.splice(i, 1);
1373 } else if (i && components[i] == '..' &&
1374 components[i - 1] && components[i - 1] != '..') {
1375 components.splice(--i, 2);
1376 } else {
1377 i++;
1378 }
1379 }
1380 return components.join('/');
1381};
1382
1383
1384/**
1385 * Loads file by synchronous XHR. Should not be used in production environments.
1386 * @param {string} src Source URL.
1387 * @return {string} File contents.
1388 * @private
1389 */
1390goog.loadFileSync_ = function(src) {
1391 if (goog.global.CLOSURE_LOAD_FILE_SYNC) {
1392 return goog.global.CLOSURE_LOAD_FILE_SYNC(src);
1393 } else {
1394 /** @type {XMLHttpRequest} */
1395 var xhr = new goog.global['XMLHttpRequest']();
1396 xhr.open('get', src, false);
1397 xhr.send();
1398 return xhr.responseText;
1399 }
1400};
1401
1402
1403/**
1404 * Retrieve and execute a module.
1405 * @param {string} src Script source URL.
1406 * @private
1407 */
1408goog.retrieveAndExecModule_ = function(src) {
1409 if (!COMPILED) {
1410 // The full but non-canonicalized URL for later use.
1411 var originalPath = src;
1412 // Canonicalize the path, removing any /./ or /../ since Chrome's debugging
1413 // console doesn't auto-canonicalize XHR loads as it does <script> srcs.
1414 src = goog.normalizePath_(src);
1415
1416 var importScript = goog.global.CLOSURE_IMPORT_SCRIPT ||
1417 goog.writeScriptTag_;
1418
1419 var scriptText = goog.loadFileSync_(src);
1420
1421 if (scriptText != null) {
1422 var execModuleScript = goog.wrapModule_(src, scriptText);
1423 var isOldIE = goog.IS_OLD_IE_;
1424 if (isOldIE) {
1425 goog.dependencies_.deferred[originalPath] = execModuleScript;
1426 goog.queuedModules_.push(originalPath);
1427 } else {
1428 importScript(src, execModuleScript);
1429 }
1430 } else {
1431 throw new Error('load of ' + src + 'failed');
1432 }
1433 }
1434};
1435
1436
1437//==============================================================================
1438// Language Enhancements
1439//==============================================================================
1440
1441
1442/**
1443 * This is a "fixed" version of the typeof operator. It differs from the typeof
1444 * operator in such a way that null returns 'null' and arrays return 'array'.
1445 * @param {?} value The value to get the type of.
1446 * @return {string} The name of the type.
1447 */
1448goog.typeOf = function(value) {
1449 var s = typeof value;
1450 if (s == 'object') {
1451 if (value) {
1452 // Check these first, so we can avoid calling Object.prototype.toString if
1453 // possible.
1454 //
1455 // IE improperly marshals tyepof across execution contexts, but a
1456 // cross-context object will still return false for "instanceof Object".
1457 if (value instanceof Array) {
1458 return 'array';
1459 } else if (value instanceof Object) {
1460 return s;
1461 }
1462
1463 // HACK: In order to use an Object prototype method on the arbitrary
1464 // value, the compiler requires the value be cast to type Object,
1465 // even though the ECMA spec explicitly allows it.
1466 var className = Object.prototype.toString.call(
1467 /** @type {!Object} */ (value));
1468 // In Firefox 3.6, attempting to access iframe window objects' length
1469 // property throws an NS_ERROR_FAILURE, so we need to special-case it
1470 // here.
1471 if (className == '[object Window]') {
1472 return 'object';
1473 }
1474
1475 // We cannot always use constructor == Array or instanceof Array because
1476 // different frames have different Array objects. In IE6, if the iframe
1477 // where the array was created is destroyed, the array loses its
1478 // prototype. Then dereferencing val.splice here throws an exception, so
1479 // we can't use goog.isFunction. Calling typeof directly returns 'unknown'
1480 // so that will work. In this case, this function will return false and
1481 // most array functions will still work because the array is still
1482 // array-like (supports length and []) even though it has lost its
1483 // prototype.
1484 // Mark Miller noticed that Object.prototype.toString
1485 // allows access to the unforgeable [[Class]] property.
1486 // 15.2.4.2 Object.prototype.toString ( )
1487 // When the toString method is called, the following steps are taken:
1488 // 1. Get the [[Class]] property of this object.
1489 // 2. Compute a string value by concatenating the three strings
1490 // "[object ", Result(1), and "]".
1491 // 3. Return Result(2).
1492 // and this behavior survives the destruction of the execution context.
1493 if ((className == '[object Array]' ||
1494 // In IE all non value types are wrapped as objects across window
1495 // boundaries (not iframe though) so we have to do object detection
1496 // for this edge case.
1497 typeof value.length == 'number' &&
1498 typeof value.splice != 'undefined' &&
1499 typeof value.propertyIsEnumerable != 'undefined' &&
1500 !value.propertyIsEnumerable('splice')
1501
1502 )) {
1503 return 'array';
1504 }
1505 // HACK: There is still an array case that fails.
1506 // function ArrayImpostor() {}
1507 // ArrayImpostor.prototype = [];
1508 // var impostor = new ArrayImpostor;
1509 // this can be fixed by getting rid of the fast path
1510 // (value instanceof Array) and solely relying on
1511 // (value && Object.prototype.toString.vall(value) === '[object Array]')
1512 // but that would require many more function calls and is not warranted
1513 // unless closure code is receiving objects from untrusted sources.
1514
1515 // IE in cross-window calls does not correctly marshal the function type
1516 // (it appears just as an object) so we cannot use just typeof val ==
1517 // 'function'. However, if the object has a call property, it is a
1518 // function.
1519 if ((className == '[object Function]' ||
1520 typeof value.call != 'undefined' &&
1521 typeof value.propertyIsEnumerable != 'undefined' &&
1522 !value.propertyIsEnumerable('call'))) {
1523 return 'function';
1524 }
1525
1526 } else {
1527 return 'null';
1528 }
1529
1530 } else if (s == 'function' && typeof value.call == 'undefined') {
1531 // In Safari typeof nodeList returns 'function', and on Firefox typeof
1532 // behaves similarly for HTML{Applet,Embed,Object}, Elements and RegExps. We
1533 // would like to return object for those and we can detect an invalid
1534 // function by making sure that the function object has a call method.
1535 return 'object';
1536 }
1537 return s;
1538};
1539
1540
1541/**
1542 * Returns true if the specified value is null.
1543 * @param {?} val Variable to test.
1544 * @return {boolean} Whether variable is null.
1545 */
1546goog.isNull = function(val) {
1547 return val === null;
1548};
1549
1550
1551/**
1552 * Returns true if the specified value is defined and not null.
1553 * @param {?} val Variable to test.
1554 * @return {boolean} Whether variable is defined and not null.
1555 */
1556goog.isDefAndNotNull = function(val) {
1557 // Note that undefined == null.
1558 return val != null;
1559};
1560
1561
1562/**
1563 * Returns true if the specified value is an array.
1564 * @param {?} val Variable to test.
1565 * @return {boolean} Whether variable is an array.
1566 */
1567goog.isArray = function(val) {
1568 return goog.typeOf(val) == 'array';
1569};
1570
1571
1572/**
1573 * Returns true if the object looks like an array. To qualify as array like
1574 * the value needs to be either a NodeList or an object with a Number length
1575 * property. As a special case, a function value is not array like, because its
1576 * length property is fixed to correspond to the number of expected arguments.
1577 * @param {?} val Variable to test.
1578 * @return {boolean} Whether variable is an array.
1579 */
1580goog.isArrayLike = function(val) {
1581 var type = goog.typeOf(val);
1582 // We do not use goog.isObject here in order to exclude function values.
1583 return type == 'array' || type == 'object' && typeof val.length == 'number';
1584};
1585
1586
1587/**
1588 * Returns true if the object looks like a Date. To qualify as Date-like the
1589 * value needs to be an object and have a getFullYear() function.
1590 * @param {?} val Variable to test.
1591 * @return {boolean} Whether variable is a like a Date.
1592 */
1593goog.isDateLike = function(val) {
1594 return goog.isObject(val) && typeof val.getFullYear == 'function';
1595};
1596
1597
1598/**
1599 * Returns true if the specified value is a string.
1600 * @param {?} val Variable to test.
1601 * @return {boolean} Whether variable is a string.
1602 */
1603goog.isString = function(val) {
1604 return typeof val == 'string';
1605};
1606
1607
1608/**
1609 * Returns true if the specified value is a boolean.
1610 * @param {?} val Variable to test.
1611 * @return {boolean} Whether variable is boolean.
1612 */
1613goog.isBoolean = function(val) {
1614 return typeof val == 'boolean';
1615};
1616
1617
1618/**
1619 * Returns true if the specified value is a number.
1620 * @param {?} val Variable to test.
1621 * @return {boolean} Whether variable is a number.
1622 */
1623goog.isNumber = function(val) {
1624 return typeof val == 'number';
1625};
1626
1627
1628/**
1629 * Returns true if the specified value is a function.
1630 * @param {?} val Variable to test.
1631 * @return {boolean} Whether variable is a function.
1632 */
1633goog.isFunction = function(val) {
1634 return goog.typeOf(val) == 'function';
1635};
1636
1637
1638/**
1639 * Returns true if the specified value is an object. This includes arrays and
1640 * functions.
1641 * @param {?} val Variable to test.
1642 * @return {boolean} Whether variable is an object.
1643 */
1644goog.isObject = function(val) {
1645 var type = typeof val;
1646 return type == 'object' && val != null || type == 'function';
1647 // return Object(val) === val also works, but is slower, especially if val is
1648 // not an object.
1649};
1650
1651
1652/**
1653 * Gets a unique ID for an object. This mutates the object so that further calls
1654 * with the same object as a parameter returns the same value. The unique ID is
1655 * guaranteed to be unique across the current session amongst objects that are
1656 * passed into {@code getUid}. There is no guarantee that the ID is unique or
1657 * consistent across sessions. It is unsafe to generate unique ID for function
1658 * prototypes.
1659 *
1660 * @param {Object} obj The object to get the unique ID for.
1661 * @return {number} The unique ID for the object.
1662 */
1663goog.getUid = function(obj) {
1664 // TODO(arv): Make the type stricter, do not accept null.
1665
1666 // In Opera window.hasOwnProperty exists but always returns false so we avoid
1667 // using it. As a consequence the unique ID generated for BaseClass.prototype
1668 // and SubClass.prototype will be the same.
1669 return obj[goog.UID_PROPERTY_] ||
1670 (obj[goog.UID_PROPERTY_] = ++goog.uidCounter_);
1671};
1672
1673
1674/**
1675 * Whether the given object is already assigned a unique ID.
1676 *
1677 * This does not modify the object.
1678 *
1679 * @param {!Object} obj The object to check.
1680 * @return {boolean} Whether there is an assigned unique id for the object.
1681 */
1682goog.hasUid = function(obj) {
1683 return !!obj[goog.UID_PROPERTY_];
1684};
1685
1686
1687/**
1688 * Removes the unique ID from an object. This is useful if the object was
1689 * previously mutated using {@code goog.getUid} in which case the mutation is
1690 * undone.
1691 * @param {Object} obj The object to remove the unique ID field from.
1692 */
1693goog.removeUid = function(obj) {
1694 // TODO(arv): Make the type stricter, do not accept null.
1695
1696 // In IE, DOM nodes are not instances of Object and throw an exception if we
1697 // try to delete. Instead we try to use removeAttribute.
1698 if ('removeAttribute' in /** @type {!Object} */ (obj)) {
1699 obj.removeAttribute(goog.UID_PROPERTY_);
1700 }
1701 /** @preserveTry */
1702 try {
1703 delete obj[goog.UID_PROPERTY_];
1704 } catch (ex) {
1705 }
1706};
1707
1708
1709/**
1710 * Name for unique ID property. Initialized in a way to help avoid collisions
1711 * with other closure JavaScript on the same page.
1712 * @type {string}
1713 * @private
1714 */
1715goog.UID_PROPERTY_ = 'closure_uid_' + ((Math.random() * 1e9) >>> 0);
1716
1717
1718/**
1719 * Counter for UID.
1720 * @type {number}
1721 * @private
1722 */
1723goog.uidCounter_ = 0;
1724
1725
1726/**
1727 * Adds a hash code field to an object. The hash code is unique for the
1728 * given object.
1729 * @param {Object} obj The object to get the hash code for.
1730 * @return {number} The hash code for the object.
1731 * @deprecated Use goog.getUid instead.
1732 */
1733goog.getHashCode = goog.getUid;
1734
1735
1736/**
1737 * Removes the hash code field from an object.
1738 * @param {Object} obj The object to remove the field from.
1739 * @deprecated Use goog.removeUid instead.
1740 */
1741goog.removeHashCode = goog.removeUid;
1742
1743
1744/**
1745 * Clones a value. The input may be an Object, Array, or basic type. Objects and
1746 * arrays will be cloned recursively.
1747 *
1748 * WARNINGS:
1749 * <code>goog.cloneObject</code> does not detect reference loops. Objects that
1750 * refer to themselves will cause infinite recursion.
1751 *
1752 * <code>goog.cloneObject</code> is unaware of unique identifiers, and copies
1753 * UIDs created by <code>getUid</code> into cloned results.
1754 *
1755 * @param {*} obj The value to clone.
1756 * @return {*} A clone of the input value.
1757 * @deprecated goog.cloneObject is unsafe. Prefer the goog.object methods.
1758 */
1759goog.cloneObject = function(obj) {
1760 var type = goog.typeOf(obj);
1761 if (type == 'object' || type == 'array') {
1762 if (obj.clone) {
1763 return obj.clone();
1764 }
1765 var clone = type == 'array' ? [] : {};
1766 for (var key in obj) {
1767 clone[key] = goog.cloneObject(obj[key]);
1768 }
1769 return clone;
1770 }
1771
1772 return obj;
1773};
1774
1775
1776/**
1777 * A native implementation of goog.bind.
1778 * @param {Function} fn A function to partially apply.
1779 * @param {Object|undefined} selfObj Specifies the object which this should
1780 * point to when the function is run.
1781 * @param {...*} var_args Additional arguments that are partially applied to the
1782 * function.
1783 * @return {!Function} A partially-applied form of the function bind() was
1784 * invoked as a method of.
1785 * @private
1786 * @suppress {deprecated} The compiler thinks that Function.prototype.bind is
1787 * deprecated because some people have declared a pure-JS version.
1788 * Only the pure-JS version is truly deprecated.
1789 */
1790goog.bindNative_ = function(fn, selfObj, var_args) {
1791 return /** @type {!Function} */ (fn.call.apply(fn.bind, arguments));
1792};
1793
1794
1795/**
1796 * A pure-JS implementation of goog.bind.
1797 * @param {Function} fn A function to partially apply.
1798 * @param {Object|undefined} selfObj Specifies the object which this should
1799 * point to when the function is run.
1800 * @param {...*} var_args Additional arguments that are partially applied to the
1801 * function.
1802 * @return {!Function} A partially-applied form of the function bind() was
1803 * invoked as a method of.
1804 * @private
1805 */
1806goog.bindJs_ = function(fn, selfObj, var_args) {
1807 if (!fn) {
1808 throw new Error();
1809 }
1810
1811 if (arguments.length > 2) {
1812 var boundArgs = Array.prototype.slice.call(arguments, 2);
1813 return function() {
1814 // Prepend the bound arguments to the current arguments.
1815 var newArgs = Array.prototype.slice.call(arguments);
1816 Array.prototype.unshift.apply(newArgs, boundArgs);
1817 return fn.apply(selfObj, newArgs);
1818 };
1819
1820 } else {
1821 return function() {
1822 return fn.apply(selfObj, arguments);
1823 };
1824 }
1825};
1826
1827
1828/**
1829 * Partially applies this function to a particular 'this object' and zero or
1830 * more arguments. The result is a new function with some arguments of the first
1831 * function pre-filled and the value of this 'pre-specified'.
1832 *
1833 * Remaining arguments specified at call-time are appended to the pre-specified
1834 * ones.
1835 *
1836 * Also see: {@link #partial}.
1837 *
1838 * Usage:
1839 * <pre>var barMethBound = goog.bind(myFunction, myObj, 'arg1', 'arg2');
1840 * barMethBound('arg3', 'arg4');</pre>
1841 *
1842 * @param {?function(this:T, ...)} fn A function to partially apply.
1843 * @param {T} selfObj Specifies the object which this should point to when the
1844 * function is run.
1845 * @param {...*} var_args Additional arguments that are partially applied to the
1846 * function.
1847 * @return {!Function} A partially-applied form of the function goog.bind() was
1848 * invoked as a method of.
1849 * @template T
1850 * @suppress {deprecated} See above.
1851 */
1852goog.bind = function(fn, selfObj, var_args) {
1853 // TODO(nicksantos): narrow the type signature.
1854 if (Function.prototype.bind &&
1855 // NOTE(nicksantos): Somebody pulled base.js into the default Chrome
1856 // extension environment. This means that for Chrome extensions, they get
1857 // the implementation of Function.prototype.bind that calls goog.bind
1858 // instead of the native one. Even worse, we don't want to introduce a
1859 // circular dependency between goog.bind and Function.prototype.bind, so
1860 // we have to hack this to make sure it works correctly.
1861 Function.prototype.bind.toString().indexOf('native code') != -1) {
1862 goog.bind = goog.bindNative_;
1863 } else {
1864 goog.bind = goog.bindJs_;
1865 }
1866 return goog.bind.apply(null, arguments);
1867};
1868
1869
1870/**
1871 * Like goog.bind(), except that a 'this object' is not required. Useful when
1872 * the target function is already bound.
1873 *
1874 * Usage:
1875 * var g = goog.partial(f, arg1, arg2);
1876 * g(arg3, arg4);
1877 *
1878 * @param {Function} fn A function to partially apply.
1879 * @param {...*} var_args Additional arguments that are partially applied to fn.
1880 * @return {!Function} A partially-applied form of the function goog.partial()
1881 * was invoked as a method of.
1882 */
1883goog.partial = function(fn, var_args) {
1884 var args = Array.prototype.slice.call(arguments, 1);
1885 return function() {
1886 // Clone the array (with slice()) and append additional arguments
1887 // to the existing arguments.
1888 var newArgs = args.slice();
1889 newArgs.push.apply(newArgs, arguments);
1890 return fn.apply(this, newArgs);
1891 };
1892};
1893
1894
1895/**
1896 * Copies all the members of a source object to a target object. This method
1897 * does not work on all browsers for all objects that contain keys such as
1898 * toString or hasOwnProperty. Use goog.object.extend for this purpose.
1899 * @param {Object} target Target.
1900 * @param {Object} source Source.
1901 */
1902goog.mixin = function(target, source) {
1903 for (var x in source) {
1904 target[x] = source[x];
1905 }
1906
1907 // For IE7 or lower, the for-in-loop does not contain any properties that are
1908 // not enumerable on the prototype object (for example, isPrototypeOf from
1909 // Object.prototype) but also it will not include 'replace' on objects that
1910 // extend String and change 'replace' (not that it is common for anyone to
1911 // extend anything except Object).
1912};
1913
1914
1915/**
1916 * @return {number} An integer value representing the number of milliseconds
1917 * between midnight, January 1, 1970 and the current time.
1918 */
1919goog.now = (goog.TRUSTED_SITE && Date.now) || (function() {
1920 // Unary plus operator converts its operand to a number which in the case of
1921 // a date is done by calling getTime().
1922 return +new Date();
1923});
1924
1925
1926/**
1927 * Evals JavaScript in the global scope. In IE this uses execScript, other
1928 * browsers use goog.global.eval. If goog.global.eval does not evaluate in the
1929 * global scope (for example, in Safari), appends a script tag instead.
1930 * Throws an exception if neither execScript or eval is defined.
1931 * @param {string} script JavaScript string.
1932 */
1933goog.globalEval = function(script) {
1934 if (goog.global.execScript) {
1935 goog.global.execScript(script, 'JavaScript');
1936 } else if (goog.global.eval) {
1937 // Test to see if eval works
1938 if (goog.evalWorksForGlobals_ == null) {
1939 goog.global.eval('var _evalTest_ = 1;');
1940 if (typeof goog.global['_evalTest_'] != 'undefined') {
1941 try {
1942 delete goog.global['_evalTest_'];
1943 } catch (ignore) {
1944 // Microsoft edge fails the deletion above in strict mode.
1945 }
1946 goog.evalWorksForGlobals_ = true;
1947 } else {
1948 goog.evalWorksForGlobals_ = false;
1949 }
1950 }
1951
1952 if (goog.evalWorksForGlobals_) {
1953 goog.global.eval(script);
1954 } else {
1955 /** @type {Document} */
1956 var doc = goog.global.document;
1957 var scriptElt = /** @type {!HTMLScriptElement} */ (
1958 doc.createElement('SCRIPT'));
1959 scriptElt.type = 'text/javascript';
1960 scriptElt.defer = false;
1961 // Note(user): can't use .innerHTML since "t('<test>')" will fail and
1962 // .text doesn't work in Safari 2. Therefore we append a text node.
1963 scriptElt.appendChild(doc.createTextNode(script));
1964 doc.body.appendChild(scriptElt);
1965 doc.body.removeChild(scriptElt);
1966 }
1967 } else {
1968 throw Error('goog.globalEval not available');
1969 }
1970};
1971
1972
1973/**
1974 * Indicates whether or not we can call 'eval' directly to eval code in the
1975 * global scope. Set to a Boolean by the first call to goog.globalEval (which
1976 * empirically tests whether eval works for globals). @see goog.globalEval
1977 * @type {?boolean}
1978 * @private
1979 */
1980goog.evalWorksForGlobals_ = null;
1981
1982
1983/**
1984 * Optional map of CSS class names to obfuscated names used with
1985 * goog.getCssName().
1986 * @private {!Object<string, string>|undefined}
1987 * @see goog.setCssNameMapping
1988 */
1989goog.cssNameMapping_;
1990
1991
1992/**
1993 * Optional obfuscation style for CSS class names. Should be set to either
1994 * 'BY_WHOLE' or 'BY_PART' if defined.
1995 * @type {string|undefined}
1996 * @private
1997 * @see goog.setCssNameMapping
1998 */
1999goog.cssNameMappingStyle_;
2000
2001
2002/**
2003 * Handles strings that are intended to be used as CSS class names.
2004 *
2005 * This function works in tandem with @see goog.setCssNameMapping.
2006 *
2007 * Without any mapping set, the arguments are simple joined with a hyphen and
2008 * passed through unaltered.
2009 *
2010 * When there is a mapping, there are two possible styles in which these
2011 * mappings are used. In the BY_PART style, each part (i.e. in between hyphens)
2012 * of the passed in css name is rewritten according to the map. In the BY_WHOLE
2013 * style, the full css name is looked up in the map directly. If a rewrite is
2014 * not specified by the map, the compiler will output a warning.
2015 *
2016 * When the mapping is passed to the compiler, it will replace calls to
2017 * goog.getCssName with the strings from the mapping, e.g.
2018 * var x = goog.getCssName('foo');
2019 * var y = goog.getCssName(this.baseClass, 'active');
2020 * becomes:
2021 * var x = 'foo';
2022 * var y = this.baseClass + '-active';
2023 *
2024 * If one argument is passed it will be processed, if two are passed only the
2025 * modifier will be processed, as it is assumed the first argument was generated
2026 * as a result of calling goog.getCssName.
2027 *
2028 * @param {string} className The class name.
2029 * @param {string=} opt_modifier A modifier to be appended to the class name.
2030 * @return {string} The class name or the concatenation of the class name and
2031 * the modifier.
2032 */
2033goog.getCssName = function(className, opt_modifier) {
2034 var getMapping = function(cssName) {
2035 return goog.cssNameMapping_[cssName] || cssName;
2036 };
2037
2038 var renameByParts = function(cssName) {
2039 // Remap all the parts individually.
2040 var parts = cssName.split('-');
2041 var mapped = [];
2042 for (var i = 0; i < parts.length; i++) {
2043 mapped.push(getMapping(parts[i]));
2044 }
2045 return mapped.join('-');
2046 };
2047
2048 var rename;
2049 if (goog.cssNameMapping_) {
2050 rename = goog.cssNameMappingStyle_ == 'BY_WHOLE' ?
2051 getMapping : renameByParts;
2052 } else {
2053 rename = function(a) {
2054 return a;
2055 };
2056 }
2057
2058 if (opt_modifier) {
2059 return className + '-' + rename(opt_modifier);
2060 } else {
2061 return rename(className);
2062 }
2063};
2064
2065
2066/**
2067 * Sets the map to check when returning a value from goog.getCssName(). Example:
2068 * <pre>
2069 * goog.setCssNameMapping({
2070 * "goog": "a",
2071 * "disabled": "b",
2072 * });
2073 *
2074 * var x = goog.getCssName('goog');
2075 * // The following evaluates to: "a a-b".
2076 * goog.getCssName('goog') + ' ' + goog.getCssName(x, 'disabled')
2077 * </pre>
2078 * When declared as a map of string literals to string literals, the JSCompiler
2079 * will replace all calls to goog.getCssName() using the supplied map if the
2080 * --process_closure_primitives flag is set.
2081 *
2082 * @param {!Object} mapping A map of strings to strings where keys are possible
2083 * arguments to goog.getCssName() and values are the corresponding values
2084 * that should be returned.
2085 * @param {string=} opt_style The style of css name mapping. There are two valid
2086 * options: 'BY_PART', and 'BY_WHOLE'.
2087 * @see goog.getCssName for a description.
2088 */
2089goog.setCssNameMapping = function(mapping, opt_style) {
2090 goog.cssNameMapping_ = mapping;
2091 goog.cssNameMappingStyle_ = opt_style;
2092};
2093
2094
2095/**
2096 * To use CSS renaming in compiled mode, one of the input files should have a
2097 * call to goog.setCssNameMapping() with an object literal that the JSCompiler
2098 * can extract and use to replace all calls to goog.getCssName(). In uncompiled
2099 * mode, JavaScript code should be loaded before this base.js file that declares
2100 * a global variable, CLOSURE_CSS_NAME_MAPPING, which is used below. This is
2101 * to ensure that the mapping is loaded before any calls to goog.getCssName()
2102 * are made in uncompiled mode.
2103 *
2104 * A hook for overriding the CSS name mapping.
2105 * @type {!Object<string, string>|undefined}
2106 */
2107goog.global.CLOSURE_CSS_NAME_MAPPING;
2108
2109
2110if (!COMPILED && goog.global.CLOSURE_CSS_NAME_MAPPING) {
2111 // This does not call goog.setCssNameMapping() because the JSCompiler
2112 // requires that goog.setCssNameMapping() be called with an object literal.
2113 goog.cssNameMapping_ = goog.global.CLOSURE_CSS_NAME_MAPPING;
2114}
2115
2116
2117/**
2118 * Gets a localized message.
2119 *
2120 * This function is a compiler primitive. If you give the compiler a localized
2121 * message bundle, it will replace the string at compile-time with a localized
2122 * version, and expand goog.getMsg call to a concatenated string.
2123 *
2124 * Messages must be initialized in the form:
2125 * <code>
2126 * var MSG_NAME = goog.getMsg('Hello {$placeholder}', {'placeholder': 'world'});
2127 * </code>
2128 *
2129 * @param {string} str Translatable string, places holders in the form {$foo}.
2130 * @param {Object<string, string>=} opt_values Maps place holder name to value.
2131 * @return {string} message with placeholders filled.
2132 */
2133goog.getMsg = function(str, opt_values) {
2134 if (opt_values) {
2135 str = str.replace(/\{\$([^}]+)}/g, function(match, key) {
2136 return (opt_values != null && key in opt_values) ?
2137 opt_values[key] : match;
2138 });
2139 }
2140 return str;
2141};
2142
2143
2144/**
2145 * Gets a localized message. If the message does not have a translation, gives a
2146 * fallback message.
2147 *
2148 * This is useful when introducing a new message that has not yet been
2149 * translated into all languages.
2150 *
2151 * This function is a compiler primitive. Must be used in the form:
2152 * <code>var x = goog.getMsgWithFallback(MSG_A, MSG_B);</code>
2153 * where MSG_A and MSG_B were initialized with goog.getMsg.
2154 *
2155 * @param {string} a The preferred message.
2156 * @param {string} b The fallback message.
2157 * @return {string} The best translated message.
2158 */
2159goog.getMsgWithFallback = function(a, b) {
2160 return a;
2161};
2162
2163
2164/**
2165 * Exposes an unobfuscated global namespace path for the given object.
2166 * Note that fields of the exported object *will* be obfuscated, unless they are
2167 * exported in turn via this function or goog.exportProperty.
2168 *
2169 * Also handy for making public items that are defined in anonymous closures.
2170 *
2171 * ex. goog.exportSymbol('public.path.Foo', Foo);
2172 *
2173 * ex. goog.exportSymbol('public.path.Foo.staticFunction', Foo.staticFunction);
2174 * public.path.Foo.staticFunction();
2175 *
2176 * ex. goog.exportSymbol('public.path.Foo.prototype.myMethod',
2177 * Foo.prototype.myMethod);
2178 * new public.path.Foo().myMethod();
2179 *
2180 * @param {string} publicPath Unobfuscated name to export.
2181 * @param {*} object Object the name should point to.
2182 * @param {Object=} opt_objectToExportTo The object to add the path to; default
2183 * is goog.global.
2184 */
2185goog.exportSymbol = function(publicPath, object, opt_objectToExportTo) {
2186 goog.exportPath_(publicPath, object, opt_objectToExportTo);
2187};
2188
2189
2190/**
2191 * Exports a property unobfuscated into the object's namespace.
2192 * ex. goog.exportProperty(Foo, 'staticFunction', Foo.staticFunction);
2193 * ex. goog.exportProperty(Foo.prototype, 'myMethod', Foo.prototype.myMethod);
2194 * @param {Object} object Object whose static property is being exported.
2195 * @param {string} publicName Unobfuscated name to export.
2196 * @param {*} symbol Object the name should point to.
2197 */
2198goog.exportProperty = function(object, publicName, symbol) {
2199 object[publicName] = symbol;
2200};
2201
2202
2203/**
2204 * Inherit the prototype methods from one constructor into another.
2205 *
2206 * Usage:
2207 * <pre>
2208 * function ParentClass(a, b) { }
2209 * ParentClass.prototype.foo = function(a) { };
2210 *
2211 * function ChildClass(a, b, c) {
2212 * ChildClass.base(this, 'constructor', a, b);
2213 * }
2214 * goog.inherits(ChildClass, ParentClass);
2215 *
2216 * var child = new ChildClass('a', 'b', 'see');
2217 * child.foo(); // This works.
2218 * </pre>
2219 *
2220 * @param {!Function} childCtor Child class.
2221 * @param {!Function} parentCtor Parent class.
2222 */
2223goog.inherits = function(childCtor, parentCtor) {
2224 /** @constructor */
2225 function tempCtor() {};
2226 tempCtor.prototype = parentCtor.prototype;
2227 childCtor.superClass_ = parentCtor.prototype;
2228 childCtor.prototype = new tempCtor();
2229 /** @override */
2230 childCtor.prototype.constructor = childCtor;
2231
2232 /**
2233 * Calls superclass constructor/method.
2234 *
2235 * This function is only available if you use goog.inherits to
2236 * express inheritance relationships between classes.
2237 *
2238 * NOTE: This is a replacement for goog.base and for superClass_
2239 * property defined in childCtor.
2240 *
2241 * @param {!Object} me Should always be "this".
2242 * @param {string} methodName The method name to call. Calling
2243 * superclass constructor can be done with the special string
2244 * 'constructor'.
2245 * @param {...*} var_args The arguments to pass to superclass
2246 * method/constructor.
2247 * @return {*} The return value of the superclass method/constructor.
2248 */
2249 childCtor.base = function(me, methodName, var_args) {
2250 // Copying using loop to avoid deop due to passing arguments object to
2251 // function. This is faster in many JS engines as of late 2014.
2252 var args = new Array(arguments.length - 2);
2253 for (var i = 2; i < arguments.length; i++) {
2254 args[i - 2] = arguments[i];
2255 }
2256 return parentCtor.prototype[methodName].apply(me, args);
2257 };
2258};
2259
2260
2261/**
2262 * Call up to the superclass.
2263 *
2264 * If this is called from a constructor, then this calls the superclass
2265 * constructor with arguments 1-N.
2266 *
2267 * If this is called from a prototype method, then you must pass the name of the
2268 * method as the second argument to this function. If you do not, you will get a
2269 * runtime error. This calls the superclass' method with arguments 2-N.
2270 *
2271 * This function only works if you use goog.inherits to express inheritance
2272 * relationships between your classes.
2273 *
2274 * This function is a compiler primitive. At compile-time, the compiler will do
2275 * macro expansion to remove a lot of the extra overhead that this function
2276 * introduces. The compiler will also enforce a lot of the assumptions that this
2277 * function makes, and treat it as a compiler error if you break them.
2278 *
2279 * @param {!Object} me Should always be "this".
2280 * @param {*=} opt_methodName The method name if calling a super method.
2281 * @param {...*} var_args The rest of the arguments.
2282 * @return {*} The return value of the superclass method.
2283 * @suppress {es5Strict} This method can not be used in strict mode, but
2284 * all Closure Library consumers must depend on this file.
2285 */
2286goog.base = function(me, opt_methodName, var_args) {
2287 var caller = arguments.callee.caller;
2288
2289 if (goog.STRICT_MODE_COMPATIBLE || (goog.DEBUG && !caller)) {
2290 throw Error('arguments.caller not defined. goog.base() cannot be used ' +
2291 'with strict mode code. See ' +
2292 'http://www.ecma-international.org/ecma-262/5.1/#sec-C');
2293 }
2294
2295 if (caller.superClass_) {
2296 // Copying using loop to avoid deop due to passing arguments object to
2297 // function. This is faster in many JS engines as of late 2014.
2298 var ctorArgs = new Array(arguments.length - 1);
2299 for (var i = 1; i < arguments.length; i++) {
2300 ctorArgs[i - 1] = arguments[i];
2301 }
2302 // This is a constructor. Call the superclass constructor.
2303 return caller.superClass_.constructor.apply(me, ctorArgs);
2304 }
2305
2306 // Copying using loop to avoid deop due to passing arguments object to
2307 // function. This is faster in many JS engines as of late 2014.
2308 var args = new Array(arguments.length - 2);
2309 for (var i = 2; i < arguments.length; i++) {
2310 args[i - 2] = arguments[i];
2311 }
2312 var foundCaller = false;
2313 for (var ctor = me.constructor;
2314 ctor; ctor = ctor.superClass_ && ctor.superClass_.constructor) {
2315 if (ctor.prototype[opt_methodName] === caller) {
2316 foundCaller = true;
2317 } else if (foundCaller) {
2318 return ctor.prototype[opt_methodName].apply(me, args);
2319 }
2320 }
2321
2322 // If we did not find the caller in the prototype chain, then one of two
2323 // things happened:
2324 // 1) The caller is an instance method.
2325 // 2) This method was not called by the right caller.
2326 if (me[opt_methodName] === caller) {
2327 return me.constructor.prototype[opt_methodName].apply(me, args);
2328 } else {
2329 throw Error(
2330 'goog.base called from a method of one name ' +
2331 'to a method of a different name');
2332 }
2333};
2334
2335
2336/**
2337 * Allow for aliasing within scope functions. This function exists for
2338 * uncompiled code - in compiled code the calls will be inlined and the aliases
2339 * applied. In uncompiled code the function is simply run since the aliases as
2340 * written are valid JavaScript.
2341 *
2342 *
2343 * @param {function()} fn Function to call. This function can contain aliases
2344 * to namespaces (e.g. "var dom = goog.dom") or classes
2345 * (e.g. "var Timer = goog.Timer").
2346 */
2347goog.scope = function(fn) {
2348 fn.call(goog.global);
2349};
2350
2351
2352/*
2353 * To support uncompiled, strict mode bundles that use eval to divide source
2354 * like so:
2355 * eval('someSource;//# sourceUrl sourcefile.js');
2356 * We need to export the globally defined symbols "goog" and "COMPILED".
2357 * Exporting "goog" breaks the compiler optimizations, so we required that
2358 * be defined externally.
2359 * NOTE: We don't use goog.exportSymbol here because we don't want to trigger
2360 * extern generation when that compiler option is enabled.
2361 */
2362if (!COMPILED) {
2363 goog.global['COMPILED'] = COMPILED;
2364}
2365
2366
2367//==============================================================================
2368// goog.defineClass implementation
2369//==============================================================================
2370
2371
2372/**
2373 * Creates a restricted form of a Closure "class":
2374 * - from the compiler's perspective, the instance returned from the
2375 * constructor is sealed (no new properties may be added). This enables
2376 * better checks.
2377 * - the compiler will rewrite this definition to a form that is optimal
2378 * for type checking and optimization (initially this will be a more
2379 * traditional form).
2380 *
2381 * @param {Function} superClass The superclass, Object or null.
2382 * @param {goog.defineClass.ClassDescriptor} def
2383 * An object literal describing
2384 * the class. It may have the following properties:
2385 * "constructor": the constructor function
2386 * "statics": an object literal containing methods to add to the constructor
2387 * as "static" methods or a function that will receive the constructor
2388 * function as its only parameter to which static properties can
2389 * be added.
2390 * all other properties are added to the prototype.
2391 * @return {!Function} The class constructor.
2392 */
2393goog.defineClass = function(superClass, def) {
2394 // TODO(johnlenz): consider making the superClass an optional parameter.
2395 var constructor = def.constructor;
2396 var statics = def.statics;
2397 // Wrap the constructor prior to setting up the prototype and static methods.
2398 if (!constructor || constructor == Object.prototype.constructor) {
2399 constructor = function() {
2400 throw Error('cannot instantiate an interface (no constructor defined).');
2401 };
2402 }
2403
2404 var cls = goog.defineClass.createSealingConstructor_(constructor, superClass);
2405 if (superClass) {
2406 goog.inherits(cls, superClass);
2407 }
2408
2409 // Remove all the properties that should not be copied to the prototype.
2410 delete def.constructor;
2411 delete def.statics;
2412
2413 goog.defineClass.applyProperties_(cls.prototype, def);
2414 if (statics != null) {
2415 if (statics instanceof Function) {
2416 statics(cls);
2417 } else {
2418 goog.defineClass.applyProperties_(cls, statics);
2419 }
2420 }
2421
2422 return cls;
2423};
2424
2425
2426/**
2427 * @typedef {
2428 * !Object|
2429 * {constructor:!Function}|
2430 * {constructor:!Function, statics:(Object|function(Function):void)}}
2431 * @suppress {missingProvide}
2432 */
2433goog.defineClass.ClassDescriptor;
2434
2435
2436/**
2437 * @define {boolean} Whether the instances returned by
2438 * goog.defineClass should be sealed when possible.
2439 */
2440goog.define('goog.defineClass.SEAL_CLASS_INSTANCES', goog.DEBUG);
2441
2442
2443/**
2444 * If goog.defineClass.SEAL_CLASS_INSTANCES is enabled and Object.seal is
2445 * defined, this function will wrap the constructor in a function that seals the
2446 * results of the provided constructor function.
2447 *
2448 * @param {!Function} ctr The constructor whose results maybe be sealed.
2449 * @param {Function} superClass The superclass constructor.
2450 * @return {!Function} The replacement constructor.
2451 * @private
2452 */
2453goog.defineClass.createSealingConstructor_ = function(ctr, superClass) {
2454 if (goog.defineClass.SEAL_CLASS_INSTANCES &&
2455 Object.seal instanceof Function) {
2456 // Don't seal subclasses of unsealable-tagged legacy classes.
2457 if (superClass && superClass.prototype &&
2458 superClass.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_]) {
2459 return ctr;
2460 }
2461 /**
2462 * @this {Object}
2463 * @return {?}
2464 */
2465 var wrappedCtr = function() {
2466 // Don't seal an instance of a subclass when it calls the constructor of
2467 // its super class as there is most likely still setup to do.
2468 var instance = ctr.apply(this, arguments) || this;
2469 instance[goog.UID_PROPERTY_] = instance[goog.UID_PROPERTY_];
2470 if (this.constructor === wrappedCtr) {
2471 Object.seal(instance);
2472 }
2473 return instance;
2474 };
2475 return wrappedCtr;
2476 }
2477 return ctr;
2478};
2479
2480
2481// TODO(johnlenz): share these values with the goog.object
2482/**
2483 * The names of the fields that are defined on Object.prototype.
2484 * @type {!Array<string>}
2485 * @private
2486 * @const
2487 */
2488goog.defineClass.OBJECT_PROTOTYPE_FIELDS_ = [
2489 'constructor',
2490 'hasOwnProperty',
2491 'isPrototypeOf',
2492 'propertyIsEnumerable',
2493 'toLocaleString',
2494 'toString',
2495 'valueOf'
2496];
2497
2498
2499// TODO(johnlenz): share this function with the goog.object
2500/**
2501 * @param {!Object} target The object to add properties to.
2502 * @param {!Object} source The object to copy properties from.
2503 * @private
2504 */
2505goog.defineClass.applyProperties_ = function(target, source) {
2506 // TODO(johnlenz): update this to support ES5 getters/setters
2507
2508 var key;
2509 for (key in source) {
2510 if (Object.prototype.hasOwnProperty.call(source, key)) {
2511 target[key] = source[key];
2512 }
2513 }
2514
2515 // For IE the for-in-loop does not contain any properties that are not
2516 // enumerable on the prototype object (for example isPrototypeOf from
2517 // Object.prototype) and it will also not include 'replace' on objects that
2518 // extend String and change 'replace' (not that it is common for anyone to
2519 // extend anything except Object).
2520 for (var i = 0; i < goog.defineClass.OBJECT_PROTOTYPE_FIELDS_.length; i++) {
2521 key = goog.defineClass.OBJECT_PROTOTYPE_FIELDS_[i];
2522 if (Object.prototype.hasOwnProperty.call(source, key)) {
2523 target[key] = source[key];
2524 }
2525 }
2526};
2527
2528
2529/**
2530 * Sealing classes breaks the older idiom of assigning properties on the
2531 * prototype rather than in the constructor. As such, goog.defineClass
2532 * must not seal subclasses of these old-style classes until they are fixed.
2533 * Until then, this marks a class as "broken", instructing defineClass
2534 * not to seal subclasses.
2535 * @param {!Function} ctr The legacy constructor to tag as unsealable.
2536 */
2537goog.tagUnsealableClass = function(ctr) {
2538 if (!COMPILED && goog.defineClass.SEAL_CLASS_INSTANCES) {
2539 ctr.prototype[goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_] = true;
2540 }
2541};
2542
2543
2544/**
2545 * Name for unsealable tag property.
2546 * @const @private {string}
2547 */
2548goog.UNSEALABLE_CONSTRUCTOR_PROPERTY_ = 'goog_defineClass_legacy_unsealable';