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closure
base.js
// Copyright 2006 The Closure Library Authors. All Rights Reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS-IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. /** * @fileoverview Bootstrap for the Google JS Library (Closure). * * In uncompiled mode base.js will write out Closure's deps file, unless the * global
CLOSURE_NO_DEPS
is set to true. This allows projects to * include their own deps file(s) from different locations. * * @author pupius@google.com (Dan Pupius) * @author arv@google.com (Erik Arvidsson) * * @provideGoog */ /** * @define {boolean} Overridden to true by the compiler when --closure_pass * or --mark_as_compiled is specified. */ var COMPILED = false; /** * Base namespace for the Closure library. Checks to see goog is * already defined in the current scope before assigning to prevent * clobbering if base.js is loaded more than once. * * @const */ var goog = goog || {}; /** * Reference to the global context. In most cases this will be 'window'. */ goog.global = this; /** * A hook for overriding the define values in uncompiled mode. * * In uncompiled mode, {@code CLOSURE_DEFINES} may be defined before loading * base.js. If a key is defined in {@code CLOSURE_DEFINES}, {@code goog.define} * will use the value instead of the default value. This allows flags to be * overwritten without compilation (this is normally accomplished with the * compiler's "define" flag). * * Example: *
* var CLOSURE_DEFINES = {'goog.DEBUG', false}; *
* * @type {Object.
|undefined} */ goog.global.CLOSURE_DEFINES; /** * Builds an object structure for the provided namespace path, * ensuring that names that already exist are not overwritten. For * example: * "a.b.c" -> a = {};a.b={};a.b.c={}; * Used by goog.provide and goog.exportSymbol. * @param {string} name name of the object that this file defines. * @param {*=} opt_object the object to expose at the end of the path. * @param {Object=} opt_objectToExportTo The object to add the path to; default * is |goog.global|. * @private */ goog.exportPath_ = function(name, opt_object, opt_objectToExportTo) { var parts = name.split('.'); var cur = opt_objectToExportTo || goog.global; // Internet Explorer exhibits strange behavior when throwing errors from // methods externed in this manner. See the testExportSymbolExceptions in // base_test.html for an example. if (!(parts[0] in cur) && cur.execScript) { cur.execScript('var ' + parts[0]); } // Certain browsers cannot parse code in the form for((a in b); c;); // This pattern is produced by the JSCompiler when it collapses the // statement above into the conditional loop below. To prevent this from // happening, use a for-loop and reserve the init logic as below. // Parentheses added to eliminate strict JS warning in Firefox. for (var part; parts.length && (part = parts.shift());) { if (!parts.length && opt_object !== undefined) { // last part and we have an object; use it cur[part] = opt_object; } else if (cur[part]) { cur = cur[part]; } else { cur = cur[part] = {}; } } }; /** * Defines a named value. In uncompiled mode, the value is retreived from * CLOSURE_DEFINES if the object is defined and has the property specified, * and otherwise used the defined defaultValue. When compiled, the default * can be overridden using compiler command-line options. * * @param {string} name The distinguished name to provide. * @param {string|number|boolean} defaultValue */ goog.define = function(name, defaultValue) { var value = defaultValue; if (!COMPILED) { if (goog.global.CLOSURE_DEFINES && Object.prototype.hasOwnProperty.call( goog.global.CLOSURE_DEFINES, name)) { value = goog.global.CLOSURE_DEFINES[name]; } } goog.exportPath_(name, value); }; /** * @define {boolean} DEBUG is provided as a convenience so that debugging code * that should not be included in a production js_binary can be easily stripped * by specifying --define goog.DEBUG=false to the JSCompiler. For example, most * toString() methods should be declared inside an "if (goog.DEBUG)" conditional * because they are generally used for debugging purposes and it is difficult * for the JSCompiler to statically determine whether they are used. */ goog.DEBUG = true; /** * @define {string} LOCALE defines the locale being used for compilation. It is * used to select locale specific data to be compiled in js binary. BUILD rule * can specify this value by "--define goog.LOCALE=
" as JSCompiler * option. * * Take into account that the locale code format is important. You should use * the canonical Unicode format with hyphen as a delimiter. Language must be * lowercase, Language Script - Capitalized, Region - UPPERCASE. * There are few examples: pt-BR, en, en-US, sr-Latin-BO, zh-Hans-CN. * * See more info about locale codes here: * http://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers * * For language codes you should use values defined by ISO 693-1. See it here * http://www.w3.org/WAI/ER/IG/ert/iso639.htm. There is only one exception from * this rule: the Hebrew language. For legacy reasons the old code (iw) should * be used instead of the new code (he), see http://wiki/Main/IIISynonyms. */ goog.define('goog.LOCALE', 'en'); // default to en /** * @define {boolean} Whether this code is running on trusted sites. * * On untrusted sites, several native functions can be defined or overridden by * external libraries like Prototype, Datejs, and JQuery and setting this flag * to false forces closure to use its own implementations when possible. * * If your javascript can be loaded by a third party site and you are wary about * relying on non-standard implementations, specify * "--define goog.TRUSTED_SITE=false" to the JSCompiler. */ goog.define('goog.TRUSTED_SITE', true); /** * Creates object stubs for a namespace. The presence of one or more * goog.provide() calls indicate that the file defines the given * objects/namespaces. Build tools also scan for provide/require statements * to discern dependencies, build dependency files (see deps.js), etc. * @see goog.require * @param {string} name Namespace provided by this file in the form * "goog.package.part". */ goog.provide = function(name) { if (!COMPILED) { // Ensure that the same namespace isn't provided twice. This is intended // to teach new developers that 'goog.provide' is effectively a variable // declaration. And when JSCompiler transforms goog.provide into a real // variable declaration, the compiled JS should work the same as the raw // JS--even when the raw JS uses goog.provide incorrectly. if (goog.isProvided_(name)) { throw Error('Namespace "' + name + '" already declared.'); } delete goog.implicitNamespaces_[name]; var namespace = name; while ((namespace = namespace.substring(0, namespace.lastIndexOf('.')))) { if (goog.getObjectByName(namespace)) { break; } goog.implicitNamespaces_[namespace] = true; } } goog.exportPath_(name); }; /** * Marks that the current file should only be used for testing, and never for * live code in production. * * In the case of unit tests, the message may optionally be an exact * namespace for the test (e.g. 'goog.stringTest'). The linter will then * ignore the extra provide (if not explicitly defined in the code). * * @param {string=} opt_message Optional message to add to the error that's * raised when used in production code. */ goog.setTestOnly = function(opt_message) { if (COMPILED && !goog.DEBUG) { opt_message = opt_message || ''; throw Error('Importing test-only code into non-debug environment' + opt_message ? ': ' + opt_message : '.'); } }; if (!COMPILED) { /** * Check if the given name has been goog.provided. This will return false for * names that are available only as implicit namespaces. * @param {string} name name of the object to look for. * @return {boolean} Whether the name has been provided. * @private */ goog.isProvided_ = function(name) { return !goog.implicitNamespaces_[name] && !!goog.getObjectByName(name); }; /** * Namespaces implicitly defined by goog.provide. For example, * goog.provide('goog.events.Event') implicitly declares * that 'goog' and 'goog.events' must be namespaces. * * @type {Object} * @private */ goog.implicitNamespaces_ = {}; } /** * Returns an object based on its fully qualified external name. If you are * using a compilation pass that renames property names beware that using this * function will not find renamed properties. * * @param {string} name The fully qualified name. * @param {Object=} opt_obj The object within which to look; default is * |goog.global|. * @return {?} The value (object or primitive) or, if not found, null. */ goog.getObjectByName = function(name, opt_obj) { var parts = name.split('.'); var cur = opt_obj || goog.global; for (var part; part = parts.shift(); ) { if (goog.isDefAndNotNull(cur[part])) { cur = cur[part]; } else { return null; } } return cur; }; /** * Globalizes a whole namespace, such as goog or goog.lang. * * @param {Object} obj The namespace to globalize. * @param {Object=} opt_global The object to add the properties to. * @deprecated Properties may be explicitly exported to the global scope, but * this should no longer be done in bulk. */ goog.globalize = function(obj, opt_global) { var global = opt_global || goog.global; for (var x in obj) { global[x] = obj[x]; } }; /** * Adds a dependency from a file to the files it requires. * @param {string} relPath The path to the js file. * @param {Array} provides An array of strings with the names of the objects * this file provides. * @param {Array} requires An array of strings with the names of the objects * this file requires. */ goog.addDependency = function(relPath, provides, requires) { if (goog.DEPENDENCIES_ENABLED) { var provide, require; var path = relPath.replace(/\\/g, '/'); var deps = goog.dependencies_; for (var i = 0; provide = provides[i]; i++) { deps.nameToPath[provide] = path; if (!(path in deps.pathToNames)) { deps.pathToNames[path] = {}; } deps.pathToNames[path][provide] = true; } for (var j = 0; require = requires[j]; j++) { if (!(path in deps.requires)) { deps.requires[path] = {}; } deps.requires[path][require] = true; } } }; // MOE:begin_strip /** * Whether goog.require should throw an exception if it fails. * @type {boolean} */ goog.useStrictRequires = false; // MOE:end_strip // NOTE(nnaze): The debug DOM loader was included in base.js as an orignal // way to do "debug-mode" development. The dependency system can sometimes // be confusing, as can the debug DOM loader's asyncronous nature. // // With the DOM loader, a call to goog.require() is not blocking -- the // script will not load until some point after the current script. If a // namespace is needed at runtime, it needs to be defined in a previous // script, or loaded via require() with its registered dependencies. // User-defined namespaces may need their own deps file. See http://go/js_deps, // http://go/genjsdeps, or, externally, DepsWriter. // http://code.google.com/closure/library/docs/depswriter.html // // Because of legacy clients, the DOM loader can't be easily removed from // base.js. Work is being done to make it disableable or replaceable for // different environments (DOM-less JavaScript interpreters like Rhino or V8, // for example). See bootstrap/ for more information. /** * @define {boolean} Whether to enable the debug loader. * * If enabled, a call to goog.require() will attempt to load the namespace by * appending a script tag to the DOM (if the namespace has been registered). * * If disabled, goog.require() will simply assert that the namespace has been * provided (and depend on the fact that some outside tool correctly ordered * the script). */ goog.define('goog.ENABLE_DEBUG_LOADER', true); /** * Implements a system for the dynamic resolution of dependencies * that works in parallel with the BUILD system. Note that all calls * to goog.require will be stripped by the JSCompiler when the * --closure_pass option is used. * @see goog.provide * @param {string} name Namespace to include (as was given in goog.provide()) * in the form "goog.package.part". */ goog.require = function(name) { // if the object already exists we do not need do do anything // TODO(arv): If we start to support require based on file name this has // to change // TODO(arv): If we allow goog.foo.* this has to change // TODO(arv): If we implement dynamic load after page load we should probably // not remove this code for the compiled output if (!COMPILED) { if (goog.isProvided_(name)) { return; } if (goog.ENABLE_DEBUG_LOADER) { var path = goog.getPathFromDeps_(name); if (path) { goog.included_[path] = true; goog.writeScripts_(); return; } } var errorMessage = 'goog.require could not find: ' + name; if (goog.global.console) { goog.global.console['error'](errorMessage); } // MOE:begin_strip // NOTE(nicksantos): We could always throw an error, but this would break // legacy users that depended on this failing silently. Instead, the // compiler should warn us when there are invalid goog.require calls. // For now, we simply give clients a way to turn strict mode on. if (goog.useStrictRequires) { // MOE:end_strip throw Error(errorMessage); // MOE:begin_strip } // MOE:end_strip } }; /** * Path for included scripts * @type {string} */ goog.basePath = ''; /** * A hook for overriding the base path. * @type {string|undefined} */ goog.global.CLOSURE_BASE_PATH; /** * Whether to write out Closure's deps file. By default, * the deps are written. * @type {boolean|undefined} */ goog.global.CLOSURE_NO_DEPS; /** * A function to import a single script. This is meant to be overridden when * Closure is being run in non-HTML contexts, such as web workers. It's defined * in the global scope so that it can be set before base.js is loaded, which * allows deps.js to be imported properly. * * The function is passed the script source, which is a relative URI. It should * return true if the script was imported, false otherwise. */ goog.global.CLOSURE_IMPORT_SCRIPT; /** * Null function used for default values of callbacks, etc. * @return {void} Nothing. */ goog.nullFunction = function() {}; /** * The identity function. Returns its first argument. * * @param {*=} opt_returnValue The single value that will be returned. * @param {...*} var_args Optional trailing arguments. These are ignored. * @return {?} The first argument. We can't know the type -- just pass it along * without type. * @deprecated Use goog.functions.identity instead. */ goog.identityFunction = function(opt_returnValue, var_args) { return opt_returnValue; }; /** * When defining a class Foo with an abstract method bar(), you can do: * * Foo.prototype.bar = goog.abstractMethod * * Now if a subclass of Foo fails to override bar(), an error * will be thrown when bar() is invoked. * * Note: This does not take the name of the function to override as * an argument because that would make it more difficult to obfuscate * our JavaScript code. * * @type {!Function} * @throws {Error} when invoked to indicate the method should be * overridden. */ goog.abstractMethod = function() { throw Error('unimplemented abstract method'); }; /** * Adds a {@code getInstance} static method that always return the same instance * object. * @param {!Function} ctor The constructor for the class to add the static * method to. */ goog.addSingletonGetter = function(ctor) { ctor.getInstance = function() { if (ctor.instance_) { return ctor.instance_; } if (goog.DEBUG) { // NOTE: JSCompiler can't optimize away Array#push. goog.instantiatedSingletons_[goog.instantiatedSingletons_.length] = ctor; } return ctor.instance_ = new ctor; }; }; /** * All singleton classes that have been instantiated, for testing. Don't read * it directly, use the {@code goog.testing.singleton} module. The compiler * removes this variable if unused. * @type {!Array.} * @private */ goog.instantiatedSingletons_ = []; /** * True if goog.dependencies_ is available. * @const {boolean} */ goog.DEPENDENCIES_ENABLED = !COMPILED && goog.ENABLE_DEBUG_LOADER; if (goog.DEPENDENCIES_ENABLED) { /** * Object used to keep track of urls that have already been added. This * record allows the prevention of circular dependencies. * @type {Object} * @private */ goog.included_ = {}; /** * This object is used to keep track of dependencies and other data that is * used for loading scripts * @private * @type {Object} */ goog.dependencies_ = { pathToNames: {}, // 1 to many nameToPath: {}, // 1 to 1 requires: {}, // 1 to many // used when resolving dependencies to prevent us from // visiting the file twice visited: {}, written: {} // used to keep track of script files we have written }; /** * Tries to detect whether is in the context of an HTML document. * @return {boolean} True if it looks like HTML document. * @private */ goog.inHtmlDocument_ = function() { var doc = goog.global.document; return typeof doc != 'undefined' && 'write' in doc; // XULDocument misses write. }; /** * Tries to detect the base path of the base.js script that bootstraps Closure * @private */ goog.findBasePath_ = function() { if (goog.global.CLOSURE_BASE_PATH) { goog.basePath = goog.global.CLOSURE_BASE_PATH; return; } else if (!goog.inHtmlDocument_()) { return; } var doc = goog.global.document; var scripts = doc.getElementsByTagName('script'); // Search backwards since the current script is in almost all cases the one // that has base.js. for (var i = scripts.length - 1; i >= 0; --i) { var src = scripts[i].src; var qmark = src.lastIndexOf('?'); var l = qmark == -1 ? src.length : qmark; if (src.substr(l - 7, 7) == 'base.js') { goog.basePath = src.substr(0, l - 7); return; } } }; /** * Imports a script if, and only if, that script hasn't already been imported. * (Must be called at execution time) * @param {string} src Script source. * @private */ goog.importScript_ = function(src) { var importScript = goog.global.CLOSURE_IMPORT_SCRIPT || goog.writeScriptTag_; if (!goog.dependencies_.written[src] && importScript(src)) { goog.dependencies_.written[src] = true; } }; /** * The default implementation of the import function. Writes a script tag to * import the script. * * @param {string} src The script source. * @return {boolean} True if the script was imported, false otherwise. * @private */ goog.writeScriptTag_ = function(src) { if (goog.inHtmlDocument_()) { var doc = goog.global.document; // If the user tries to require a new symbol after document load, // something has gone terribly wrong. Doing a document.write would // wipe out the page. if (doc.readyState == 'complete') { // Certain test frameworks load base.js multiple times, which tries // to write deps.js each time. If that happens, just fail silently. // These frameworks wipe the page between each load of base.js, so this // is OK. var isDeps = /\bdeps.js$/.test(src); if (isDeps) { return false; } else { throw Error('Cannot write "' + src + '" after document load'); } } doc.write( '
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