Chris@0: //     Backbone.js 1.2.3
Chris@0: 
Chris@0: //     (c) 2010-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
Chris@0: //     Backbone may be freely distributed under the MIT license.
Chris@0: //     For all details and documentation:
Chris@0: //     http://backbonejs.org
Chris@0: 
Chris@0: (function(factory) {
Chris@0: 
Chris@0:   // Establish the root object, `window` (`self`) in the browser, or `global` on the server.
Chris@0:   // We use `self` instead of `window` for `WebWorker` support.
Chris@0:   var root = (typeof self == 'object' && self.self == self && self) ||
Chris@0:             (typeof global == 'object' && global.global == global && global);
Chris@0: 
Chris@0:   // Set up Backbone appropriately for the environment. Start with AMD.
Chris@0:   if (typeof define === 'function' && define.amd) {
Chris@0:     define(['underscore', 'jquery', 'exports'], function(_, $, exports) {
Chris@0:       // Export global even in AMD case in case this script is loaded with
Chris@0:       // others that may still expect a global Backbone.
Chris@0:       root.Backbone = factory(root, exports, _, $);
Chris@0:     });
Chris@0: 
Chris@0:   // Next for Node.js or CommonJS. jQuery may not be needed as a module.
Chris@0:   } else if (typeof exports !== 'undefined') {
Chris@0:     var _ = require('underscore'), $;
Chris@0:     try { $ = require('jquery'); } catch(e) {}
Chris@0:     factory(root, exports, _, $);
Chris@0: 
Chris@0:   // Finally, as a browser global.
Chris@0:   } else {
Chris@0:     root.Backbone = factory(root, {}, root._, (root.jQuery || root.Zepto || root.ender || root.$));
Chris@0:   }
Chris@0: 
Chris@0: }(function(root, Backbone, _, $) {
Chris@0: 
Chris@0:   // Initial Setup
Chris@0:   // -------------
Chris@0: 
Chris@0:   // Save the previous value of the `Backbone` variable, so that it can be
Chris@0:   // restored later on, if `noConflict` is used.
Chris@0:   var previousBackbone = root.Backbone;
Chris@0: 
Chris@0:   // Create a local reference to a common array method we'll want to use later.
Chris@0:   var slice = Array.prototype.slice;
Chris@0: 
Chris@0:   // Current version of the library. Keep in sync with `package.json`.
Chris@0:   Backbone.VERSION = '1.2.3';
Chris@0: 
Chris@0:   // For Backbone's purposes, jQuery, Zepto, Ender, or My Library (kidding) owns
Chris@0:   // the `$` variable.
Chris@0:   Backbone.$ = $;
Chris@0: 
Chris@0:   // Runs Backbone.js in *noConflict* mode, returning the `Backbone` variable
Chris@0:   // to its previous owner. Returns a reference to this Backbone object.
Chris@0:   Backbone.noConflict = function() {
Chris@0:     root.Backbone = previousBackbone;
Chris@0:     return this;
Chris@0:   };
Chris@0: 
Chris@0:   // Turn on `emulateHTTP` to support legacy HTTP servers. Setting this option
Chris@0:   // will fake `"PATCH"`, `"PUT"` and `"DELETE"` requests via the `_method` parameter and
Chris@0:   // set a `X-Http-Method-Override` header.
Chris@0:   Backbone.emulateHTTP = false;
Chris@0: 
Chris@0:   // Turn on `emulateJSON` to support legacy servers that can't deal with direct
Chris@0:   // `application/json` requests ... this will encode the body as
Chris@0:   // `application/x-www-form-urlencoded` instead and will send the model in a
Chris@0:   // form param named `model`.
Chris@0:   Backbone.emulateJSON = false;
Chris@0: 
Chris@0:   // Proxy Backbone class methods to Underscore functions, wrapping the model's
Chris@0:   // `attributes` object or collection's `models` array behind the scenes.
Chris@0:   //
Chris@0:   // collection.filter(function(model) { return model.get('age') > 10 });
Chris@0:   // collection.each(this.addView);
Chris@0:   //
Chris@0:   // `Function#apply` can be slow so we use the method's arg count, if we know it.
Chris@0:   var addMethod = function(length, method, attribute) {
Chris@0:     switch (length) {
Chris@0:       case 1: return function() {
Chris@0:         return _[method](this[attribute]);
Chris@0:       };
Chris@0:       case 2: return function(value) {
Chris@0:         return _[method](this[attribute], value);
Chris@0:       };
Chris@0:       case 3: return function(iteratee, context) {
Chris@0:         return _[method](this[attribute], cb(iteratee, this), context);
Chris@0:       };
Chris@0:       case 4: return function(iteratee, defaultVal, context) {
Chris@0:         return _[method](this[attribute], cb(iteratee, this), defaultVal, context);
Chris@0:       };
Chris@0:       default: return function() {
Chris@0:         var args = slice.call(arguments);
Chris@0:         args.unshift(this[attribute]);
Chris@0:         return _[method].apply(_, args);
Chris@0:       };
Chris@0:     }
Chris@0:   };
Chris@0:   var addUnderscoreMethods = function(Class, methods, attribute) {
Chris@0:     _.each(methods, function(length, method) {
Chris@0:       if (_[method]) Class.prototype[method] = addMethod(length, method, attribute);
Chris@0:     });
Chris@0:   };
Chris@0: 
Chris@0:   // Support `collection.sortBy('attr')` and `collection.findWhere({id: 1})`.
Chris@0:   var cb = function(iteratee, instance) {
Chris@0:     if (_.isFunction(iteratee)) return iteratee;
Chris@0:     if (_.isObject(iteratee) && !instance._isModel(iteratee)) return modelMatcher(iteratee);
Chris@0:     if (_.isString(iteratee)) return function(model) { return model.get(iteratee); };
Chris@0:     return iteratee;
Chris@0:   };
Chris@0:   var modelMatcher = function(attrs) {
Chris@0:     var matcher = _.matches(attrs);
Chris@0:     return function(model) {
Chris@0:       return matcher(model.attributes);
Chris@0:     };
Chris@0:   };
Chris@0: 
Chris@0:   // Backbone.Events
Chris@0:   // ---------------
Chris@0: 
Chris@0:   // A module that can be mixed in to *any object* in order to provide it with
Chris@0:   // a custom event channel. You may bind a callback to an event with `on` or
Chris@0:   // remove with `off`; `trigger`-ing an event fires all callbacks in
Chris@0:   // succession.
Chris@0:   //
Chris@0:   //     var object = {};
Chris@0:   //     _.extend(object, Backbone.Events);
Chris@0:   //     object.on('expand', function(){ alert('expanded'); });
Chris@0:   //     object.trigger('expand');
Chris@0:   //
Chris@0:   var Events = Backbone.Events = {};
Chris@0: 
Chris@0:   // Regular expression used to split event strings.
Chris@0:   var eventSplitter = /\s+/;
Chris@0: 
Chris@0:   // Iterates over the standard `event, callback` (as well as the fancy multiple
Chris@0:   // space-separated events `"change blur", callback` and jQuery-style event
Chris@0:   // maps `{event: callback}`).
Chris@0:   var eventsApi = function(iteratee, events, name, callback, opts) {
Chris@0:     var i = 0, names;
Chris@0:     if (name && typeof name === 'object') {
Chris@0:       // Handle event maps.
Chris@0:       if (callback !== void 0 && 'context' in opts && opts.context === void 0) opts.context = callback;
Chris@0:       for (names = _.keys(name); i < names.length ; i++) {
Chris@0:         events = eventsApi(iteratee, events, names[i], name[names[i]], opts);
Chris@0:       }
Chris@0:     } else if (name && eventSplitter.test(name)) {
Chris@0:       // Handle space separated event names by delegating them individually.
Chris@0:       for (names = name.split(eventSplitter); i < names.length; i++) {
Chris@0:         events = iteratee(events, names[i], callback, opts);
Chris@0:       }
Chris@0:     } else {
Chris@0:       // Finally, standard events.
Chris@0:       events = iteratee(events, name, callback, opts);
Chris@0:     }
Chris@0:     return events;
Chris@0:   };
Chris@0: 
Chris@0:   // Bind an event to a `callback` function. Passing `"all"` will bind
Chris@0:   // the callback to all events fired.
Chris@0:   Events.on = function(name, callback, context) {
Chris@0:     return internalOn(this, name, callback, context);
Chris@0:   };
Chris@0: 
Chris@0:   // Guard the `listening` argument from the public API.
Chris@0:   var internalOn = function(obj, name, callback, context, listening) {
Chris@0:     obj._events = eventsApi(onApi, obj._events || {}, name, callback, {
Chris@0:         context: context,
Chris@0:         ctx: obj,
Chris@0:         listening: listening
Chris@0:     });
Chris@0: 
Chris@0:     if (listening) {
Chris@0:       var listeners = obj._listeners || (obj._listeners = {});
Chris@0:       listeners[listening.id] = listening;
Chris@0:     }
Chris@0: 
Chris@0:     return obj;
Chris@0:   };
Chris@0: 
Chris@0:   // Inversion-of-control versions of `on`. Tell *this* object to listen to
Chris@0:   // an event in another object... keeping track of what it's listening to
Chris@0:   // for easier unbinding later.
Chris@0:   Events.listenTo =  function(obj, name, callback) {
Chris@0:     if (!obj) return this;
Chris@0:     var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
Chris@0:     var listeningTo = this._listeningTo || (this._listeningTo = {});
Chris@0:     var listening = listeningTo[id];
Chris@0: 
Chris@0:     // This object is not listening to any other events on `obj` yet.
Chris@0:     // Setup the necessary references to track the listening callbacks.
Chris@0:     if (!listening) {
Chris@0:       var thisId = this._listenId || (this._listenId = _.uniqueId('l'));
Chris@0:       listening = listeningTo[id] = {obj: obj, objId: id, id: thisId, listeningTo: listeningTo, count: 0};
Chris@0:     }
Chris@0: 
Chris@0:     // Bind callbacks on obj, and keep track of them on listening.
Chris@0:     internalOn(obj, name, callback, this, listening);
Chris@0:     return this;
Chris@0:   };
Chris@0: 
Chris@0:   // The reducing API that adds a callback to the `events` object.
Chris@0:   var onApi = function(events, name, callback, options) {
Chris@0:     if (callback) {
Chris@0:       var handlers = events[name] || (events[name] = []);
Chris@0:       var context = options.context, ctx = options.ctx, listening = options.listening;
Chris@0:       if (listening) listening.count++;
Chris@0: 
Chris@0:       handlers.push({ callback: callback, context: context, ctx: context || ctx, listening: listening });
Chris@0:     }
Chris@0:     return events;
Chris@0:   };
Chris@0: 
Chris@0:   // Remove one or many callbacks. If `context` is null, removes all
Chris@0:   // callbacks with that function. If `callback` is null, removes all
Chris@0:   // callbacks for the event. If `name` is null, removes all bound
Chris@0:   // callbacks for all events.
Chris@0:   Events.off =  function(name, callback, context) {
Chris@0:     if (!this._events) return this;
Chris@0:     this._events = eventsApi(offApi, this._events, name, callback, {
Chris@0:         context: context,
Chris@0:         listeners: this._listeners
Chris@0:     });
Chris@0:     return this;
Chris@0:   };
Chris@0: 
Chris@0:   // Tell this object to stop listening to either specific events ... or
Chris@0:   // to every object it's currently listening to.
Chris@0:   Events.stopListening =  function(obj, name, callback) {
Chris@0:     var listeningTo = this._listeningTo;
Chris@0:     if (!listeningTo) return this;
Chris@0: 
Chris@0:     var ids = obj ? [obj._listenId] : _.keys(listeningTo);
Chris@0: 
Chris@0:     for (var i = 0; i < ids.length; i++) {
Chris@0:       var listening = listeningTo[ids[i]];
Chris@0: 
Chris@0:       // If listening doesn't exist, this object is not currently
Chris@0:       // listening to obj. Break out early.
Chris@0:       if (!listening) break;
Chris@0: 
Chris@0:       listening.obj.off(name, callback, this);
Chris@0:     }
Chris@0:     if (_.isEmpty(listeningTo)) this._listeningTo = void 0;
Chris@0: 
Chris@0:     return this;
Chris@0:   };
Chris@0: 
Chris@0:   // The reducing API that removes a callback from the `events` object.
Chris@0:   var offApi = function(events, name, callback, options) {
Chris@0:     if (!events) return;
Chris@0: 
Chris@0:     var i = 0, listening;
Chris@0:     var context = options.context, listeners = options.listeners;
Chris@0: 
Chris@0:     // Delete all events listeners and "drop" events.
Chris@0:     if (!name && !callback && !context) {
Chris@0:       var ids = _.keys(listeners);
Chris@0:       for (; i < ids.length; i++) {
Chris@0:         listening = listeners[ids[i]];
Chris@0:         delete listeners[listening.id];
Chris@0:         delete listening.listeningTo[listening.objId];
Chris@0:       }
Chris@0:       return;
Chris@0:     }
Chris@0: 
Chris@0:     var names = name ? [name] : _.keys(events);
Chris@0:     for (; i < names.length; i++) {
Chris@0:       name = names[i];
Chris@0:       var handlers = events[name];
Chris@0: 
Chris@0:       // Bail out if there are no events stored.
Chris@0:       if (!handlers) break;
Chris@0: 
Chris@0:       // Replace events if there are any remaining.  Otherwise, clean up.
Chris@0:       var remaining = [];
Chris@0:       for (var j = 0; j < handlers.length; j++) {
Chris@0:         var handler = handlers[j];
Chris@0:         if (
Chris@0:           callback && callback !== handler.callback &&
Chris@0:             callback !== handler.callback._callback ||
Chris@0:               context && context !== handler.context
Chris@0:         ) {
Chris@0:           remaining.push(handler);
Chris@0:         } else {
Chris@0:           listening = handler.listening;
Chris@0:           if (listening && --listening.count === 0) {
Chris@0:             delete listeners[listening.id];
Chris@0:             delete listening.listeningTo[listening.objId];
Chris@0:           }
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       // Update tail event if the list has any events.  Otherwise, clean up.
Chris@0:       if (remaining.length) {
Chris@0:         events[name] = remaining;
Chris@0:       } else {
Chris@0:         delete events[name];
Chris@0:       }
Chris@0:     }
Chris@0:     if (_.size(events)) return events;
Chris@0:   };
Chris@0: 
Chris@0:   // Bind an event to only be triggered a single time. After the first time
Chris@0:   // the callback is invoked, its listener will be removed. If multiple events
Chris@0:   // are passed in using the space-separated syntax, the handler will fire
Chris@0:   // once for each event, not once for a combination of all events.
Chris@0:   Events.once =  function(name, callback, context) {
Chris@0:     // Map the event into a `{event: once}` object.
Chris@0:     var events = eventsApi(onceMap, {}, name, callback, _.bind(this.off, this));
Chris@0:     return this.on(events, void 0, context);
Chris@0:   };
Chris@0: 
Chris@0:   // Inversion-of-control versions of `once`.
Chris@0:   Events.listenToOnce =  function(obj, name, callback) {
Chris@0:     // Map the event into a `{event: once}` object.
Chris@0:     var events = eventsApi(onceMap, {}, name, callback, _.bind(this.stopListening, this, obj));
Chris@0:     return this.listenTo(obj, events);
Chris@0:   };
Chris@0: 
Chris@0:   // Reduces the event callbacks into a map of `{event: onceWrapper}`.
Chris@0:   // `offer` unbinds the `onceWrapper` after it has been called.
Chris@0:   var onceMap = function(map, name, callback, offer) {
Chris@0:     if (callback) {
Chris@0:       var once = map[name] = _.once(function() {
Chris@0:         offer(name, once);
Chris@0:         callback.apply(this, arguments);
Chris@0:       });
Chris@0:       once._callback = callback;
Chris@0:     }
Chris@0:     return map;
Chris@0:   };
Chris@0: 
Chris@0:   // Trigger one or many events, firing all bound callbacks. Callbacks are
Chris@0:   // passed the same arguments as `trigger` is, apart from the event name
Chris@0:   // (unless you're listening on `"all"`, which will cause your callback to
Chris@0:   // receive the true name of the event as the first argument).
Chris@0:   Events.trigger =  function(name) {
Chris@0:     if (!this._events) return this;
Chris@0: 
Chris@0:     var length = Math.max(0, arguments.length - 1);
Chris@0:     var args = Array(length);
Chris@0:     for (var i = 0; i < length; i++) args[i] = arguments[i + 1];
Chris@0: 
Chris@0:     eventsApi(triggerApi, this._events, name, void 0, args);
Chris@0:     return this;
Chris@0:   };
Chris@0: 
Chris@0:   // Handles triggering the appropriate event callbacks.
Chris@0:   var triggerApi = function(objEvents, name, cb, args) {
Chris@0:     if (objEvents) {
Chris@0:       var events = objEvents[name];
Chris@0:       var allEvents = objEvents.all;
Chris@0:       if (events && allEvents) allEvents = allEvents.slice();
Chris@0:       if (events) triggerEvents(events, args);
Chris@0:       if (allEvents) triggerEvents(allEvents, [name].concat(args));
Chris@0:     }
Chris@0:     return objEvents;
Chris@0:   };
Chris@0: 
Chris@0:   // A difficult-to-believe, but optimized internal dispatch function for
Chris@0:   // triggering events. Tries to keep the usual cases speedy (most internal
Chris@0:   // Backbone events have 3 arguments).
Chris@0:   var triggerEvents = function(events, args) {
Chris@0:     var ev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2];
Chris@0:     switch (args.length) {
Chris@0:       case 0: while (++i < l) (ev = events[i]).callback.call(ev.ctx); return;
Chris@0:       case 1: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1); return;
Chris@0:       case 2: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2); return;
Chris@0:       case 3: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2, a3); return;
Chris@0:       default: while (++i < l) (ev = events[i]).callback.apply(ev.ctx, args); return;
Chris@0:     }
Chris@0:   };
Chris@0: 
Chris@0:   // Aliases for backwards compatibility.
Chris@0:   Events.bind   = Events.on;
Chris@0:   Events.unbind = Events.off;
Chris@0: 
Chris@0:   // Allow the `Backbone` object to serve as a global event bus, for folks who
Chris@0:   // want global "pubsub" in a convenient place.
Chris@0:   _.extend(Backbone, Events);
Chris@0: 
Chris@0:   // Backbone.Model
Chris@0:   // --------------
Chris@0: 
Chris@0:   // Backbone **Models** are the basic data object in the framework --
Chris@0:   // frequently representing a row in a table in a database on your server.
Chris@0:   // A discrete chunk of data and a bunch of useful, related methods for
Chris@0:   // performing computations and transformations on that data.
Chris@0: 
Chris@0:   // Create a new model with the specified attributes. A client id (`cid`)
Chris@0:   // is automatically generated and assigned for you.
Chris@0:   var Model = Backbone.Model = function(attributes, options) {
Chris@0:     var attrs = attributes || {};
Chris@0:     options || (options = {});
Chris@0:     this.cid = _.uniqueId(this.cidPrefix);
Chris@0:     this.attributes = {};
Chris@0:     if (options.collection) this.collection = options.collection;
Chris@0:     if (options.parse) attrs = this.parse(attrs, options) || {};
Chris@0:     attrs = _.defaults({}, attrs, _.result(this, 'defaults'));
Chris@0:     this.set(attrs, options);
Chris@0:     this.changed = {};
Chris@0:     this.initialize.apply(this, arguments);
Chris@0:   };
Chris@0: 
Chris@0:   // Attach all inheritable methods to the Model prototype.
Chris@0:   _.extend(Model.prototype, Events, {
Chris@0: 
Chris@0:     // A hash of attributes whose current and previous value differ.
Chris@0:     changed: null,
Chris@0: 
Chris@0:     // The value returned during the last failed validation.
Chris@0:     validationError: null,
Chris@0: 
Chris@0:     // The default name for the JSON `id` attribute is `"id"`. MongoDB and
Chris@0:     // CouchDB users may want to set this to `"_id"`.
Chris@0:     idAttribute: 'id',
Chris@0: 
Chris@0:     // The prefix is used to create the client id which is used to identify models locally.
Chris@0:     // You may want to override this if you're experiencing name clashes with model ids.
Chris@0:     cidPrefix: 'c',
Chris@0: 
Chris@0:     // Initialize is an empty function by default. Override it with your own
Chris@0:     // initialization logic.
Chris@0:     initialize: function(){},
Chris@0: 
Chris@0:     // Return a copy of the model's `attributes` object.
Chris@0:     toJSON: function(options) {
Chris@0:       return _.clone(this.attributes);
Chris@0:     },
Chris@0: 
Chris@0:     // Proxy `Backbone.sync` by default -- but override this if you need
Chris@0:     // custom syncing semantics for *this* particular model.
Chris@0:     sync: function() {
Chris@0:       return Backbone.sync.apply(this, arguments);
Chris@0:     },
Chris@0: 
Chris@0:     // Get the value of an attribute.
Chris@0:     get: function(attr) {
Chris@0:       return this.attributes[attr];
Chris@0:     },
Chris@0: 
Chris@0:     // Get the HTML-escaped value of an attribute.
Chris@0:     escape: function(attr) {
Chris@0:       return _.escape(this.get(attr));
Chris@0:     },
Chris@0: 
Chris@0:     // Returns `true` if the attribute contains a value that is not null
Chris@0:     // or undefined.
Chris@0:     has: function(attr) {
Chris@0:       return this.get(attr) != null;
Chris@0:     },
Chris@0: 
Chris@0:     // Special-cased proxy to underscore's `_.matches` method.
Chris@0:     matches: function(attrs) {
Chris@0:       return !!_.iteratee(attrs, this)(this.attributes);
Chris@0:     },
Chris@0: 
Chris@0:     // Set a hash of model attributes on the object, firing `"change"`. This is
Chris@0:     // the core primitive operation of a model, updating the data and notifying
Chris@0:     // anyone who needs to know about the change in state. The heart of the beast.
Chris@0:     set: function(key, val, options) {
Chris@0:       if (key == null) return this;
Chris@0: 
Chris@0:       // Handle both `"key", value` and `{key: value}` -style arguments.
Chris@0:       var attrs;
Chris@0:       if (typeof key === 'object') {
Chris@0:         attrs = key;
Chris@0:         options = val;
Chris@0:       } else {
Chris@0:         (attrs = {})[key] = val;
Chris@0:       }
Chris@0: 
Chris@0:       options || (options = {});
Chris@0: 
Chris@0:       // Run validation.
Chris@0:       if (!this._validate(attrs, options)) return false;
Chris@0: 
Chris@0:       // Extract attributes and options.
Chris@0:       var unset      = options.unset;
Chris@0:       var silent     = options.silent;
Chris@0:       var changes    = [];
Chris@0:       var changing   = this._changing;
Chris@0:       this._changing = true;
Chris@0: 
Chris@0:       if (!changing) {
Chris@0:         this._previousAttributes = _.clone(this.attributes);
Chris@0:         this.changed = {};
Chris@0:       }
Chris@0: 
Chris@0:       var current = this.attributes;
Chris@0:       var changed = this.changed;
Chris@0:       var prev    = this._previousAttributes;
Chris@0: 
Chris@0:       // For each `set` attribute, update or delete the current value.
Chris@0:       for (var attr in attrs) {
Chris@0:         val = attrs[attr];
Chris@0:         if (!_.isEqual(current[attr], val)) changes.push(attr);
Chris@0:         if (!_.isEqual(prev[attr], val)) {
Chris@0:           changed[attr] = val;
Chris@0:         } else {
Chris@0:           delete changed[attr];
Chris@0:         }
Chris@0:         unset ? delete current[attr] : current[attr] = val;
Chris@0:       }
Chris@0: 
Chris@0:       // Update the `id`.
Chris@0:       this.id = this.get(this.idAttribute);
Chris@0: 
Chris@0:       // Trigger all relevant attribute changes.
Chris@0:       if (!silent) {
Chris@0:         if (changes.length) this._pending = options;
Chris@0:         for (var i = 0; i < changes.length; i++) {
Chris@0:           this.trigger('change:' + changes[i], this, current[changes[i]], options);
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       // You might be wondering why there's a `while` loop here. Changes can
Chris@0:       // be recursively nested within `"change"` events.
Chris@0:       if (changing) return this;
Chris@0:       if (!silent) {
Chris@0:         while (this._pending) {
Chris@0:           options = this._pending;
Chris@0:           this._pending = false;
Chris@0:           this.trigger('change', this, options);
Chris@0:         }
Chris@0:       }
Chris@0:       this._pending = false;
Chris@0:       this._changing = false;
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Remove an attribute from the model, firing `"change"`. `unset` is a noop
Chris@0:     // if the attribute doesn't exist.
Chris@0:     unset: function(attr, options) {
Chris@0:       return this.set(attr, void 0, _.extend({}, options, {unset: true}));
Chris@0:     },
Chris@0: 
Chris@0:     // Clear all attributes on the model, firing `"change"`.
Chris@0:     clear: function(options) {
Chris@0:       var attrs = {};
Chris@0:       for (var key in this.attributes) attrs[key] = void 0;
Chris@0:       return this.set(attrs, _.extend({}, options, {unset: true}));
Chris@0:     },
Chris@0: 
Chris@0:     // Determine if the model has changed since the last `"change"` event.
Chris@0:     // If you specify an attribute name, determine if that attribute has changed.
Chris@0:     hasChanged: function(attr) {
Chris@0:       if (attr == null) return !_.isEmpty(this.changed);
Chris@0:       return _.has(this.changed, attr);
Chris@0:     },
Chris@0: 
Chris@0:     // Return an object containing all the attributes that have changed, or
Chris@0:     // false if there are no changed attributes. Useful for determining what
Chris@0:     // parts of a view need to be updated and/or what attributes need to be
Chris@0:     // persisted to the server. Unset attributes will be set to undefined.
Chris@0:     // You can also pass an attributes object to diff against the model,
Chris@0:     // determining if there *would be* a change.
Chris@0:     changedAttributes: function(diff) {
Chris@0:       if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
Chris@0:       var old = this._changing ? this._previousAttributes : this.attributes;
Chris@0:       var changed = {};
Chris@0:       for (var attr in diff) {
Chris@0:         var val = diff[attr];
Chris@0:         if (_.isEqual(old[attr], val)) continue;
Chris@0:         changed[attr] = val;
Chris@0:       }
Chris@0:       return _.size(changed) ? changed : false;
Chris@0:     },
Chris@0: 
Chris@0:     // Get the previous value of an attribute, recorded at the time the last
Chris@0:     // `"change"` event was fired.
Chris@0:     previous: function(attr) {
Chris@0:       if (attr == null || !this._previousAttributes) return null;
Chris@0:       return this._previousAttributes[attr];
Chris@0:     },
Chris@0: 
Chris@0:     // Get all of the attributes of the model at the time of the previous
Chris@0:     // `"change"` event.
Chris@0:     previousAttributes: function() {
Chris@0:       return _.clone(this._previousAttributes);
Chris@0:     },
Chris@0: 
Chris@0:     // Fetch the model from the server, merging the response with the model's
Chris@0:     // local attributes. Any changed attributes will trigger a "change" event.
Chris@0:     fetch: function(options) {
Chris@0:       options = _.extend({parse: true}, options);
Chris@0:       var model = this;
Chris@0:       var success = options.success;
Chris@0:       options.success = function(resp) {
Chris@0:         var serverAttrs = options.parse ? model.parse(resp, options) : resp;
Chris@0:         if (!model.set(serverAttrs, options)) return false;
Chris@0:         if (success) success.call(options.context, model, resp, options);
Chris@0:         model.trigger('sync', model, resp, options);
Chris@0:       };
Chris@0:       wrapError(this, options);
Chris@0:       return this.sync('read', this, options);
Chris@0:     },
Chris@0: 
Chris@0:     // Set a hash of model attributes, and sync the model to the server.
Chris@0:     // If the server returns an attributes hash that differs, the model's
Chris@0:     // state will be `set` again.
Chris@0:     save: function(key, val, options) {
Chris@0:       // Handle both `"key", value` and `{key: value}` -style arguments.
Chris@0:       var attrs;
Chris@0:       if (key == null || typeof key === 'object') {
Chris@0:         attrs = key;
Chris@0:         options = val;
Chris@0:       } else {
Chris@0:         (attrs = {})[key] = val;
Chris@0:       }
Chris@0: 
Chris@0:       options = _.extend({validate: true, parse: true}, options);
Chris@0:       var wait = options.wait;
Chris@0: 
Chris@0:       // If we're not waiting and attributes exist, save acts as
Chris@0:       // `set(attr).save(null, opts)` with validation. Otherwise, check if
Chris@0:       // the model will be valid when the attributes, if any, are set.
Chris@0:       if (attrs && !wait) {
Chris@0:         if (!this.set(attrs, options)) return false;
Chris@0:       } else {
Chris@0:         if (!this._validate(attrs, options)) return false;
Chris@0:       }
Chris@0: 
Chris@0:       // After a successful server-side save, the client is (optionally)
Chris@0:       // updated with the server-side state.
Chris@0:       var model = this;
Chris@0:       var success = options.success;
Chris@0:       var attributes = this.attributes;
Chris@0:       options.success = function(resp) {
Chris@0:         // Ensure attributes are restored during synchronous saves.
Chris@0:         model.attributes = attributes;
Chris@0:         var serverAttrs = options.parse ? model.parse(resp, options) : resp;
Chris@0:         if (wait) serverAttrs = _.extend({}, attrs, serverAttrs);
Chris@0:         if (serverAttrs && !model.set(serverAttrs, options)) return false;
Chris@0:         if (success) success.call(options.context, model, resp, options);
Chris@0:         model.trigger('sync', model, resp, options);
Chris@0:       };
Chris@0:       wrapError(this, options);
Chris@0: 
Chris@0:       // Set temporary attributes if `{wait: true}` to properly find new ids.
Chris@0:       if (attrs && wait) this.attributes = _.extend({}, attributes, attrs);
Chris@0: 
Chris@0:       var method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
Chris@0:       if (method === 'patch' && !options.attrs) options.attrs = attrs;
Chris@0:       var xhr = this.sync(method, this, options);
Chris@0: 
Chris@0:       // Restore attributes.
Chris@0:       this.attributes = attributes;
Chris@0: 
Chris@0:       return xhr;
Chris@0:     },
Chris@0: 
Chris@0:     // Destroy this model on the server if it was already persisted.
Chris@0:     // Optimistically removes the model from its collection, if it has one.
Chris@0:     // If `wait: true` is passed, waits for the server to respond before removal.
Chris@0:     destroy: function(options) {
Chris@0:       options = options ? _.clone(options) : {};
Chris@0:       var model = this;
Chris@0:       var success = options.success;
Chris@0:       var wait = options.wait;
Chris@0: 
Chris@0:       var destroy = function() {
Chris@0:         model.stopListening();
Chris@0:         model.trigger('destroy', model, model.collection, options);
Chris@0:       };
Chris@0: 
Chris@0:       options.success = function(resp) {
Chris@0:         if (wait) destroy();
Chris@0:         if (success) success.call(options.context, model, resp, options);
Chris@0:         if (!model.isNew()) model.trigger('sync', model, resp, options);
Chris@0:       };
Chris@0: 
Chris@0:       var xhr = false;
Chris@0:       if (this.isNew()) {
Chris@0:         _.defer(options.success);
Chris@0:       } else {
Chris@0:         wrapError(this, options);
Chris@0:         xhr = this.sync('delete', this, options);
Chris@0:       }
Chris@0:       if (!wait) destroy();
Chris@0:       return xhr;
Chris@0:     },
Chris@0: 
Chris@0:     // Default URL for the model's representation on the server -- if you're
Chris@0:     // using Backbone's restful methods, override this to change the endpoint
Chris@0:     // that will be called.
Chris@0:     url: function() {
Chris@0:       var base =
Chris@0:         _.result(this, 'urlRoot') ||
Chris@0:         _.result(this.collection, 'url') ||
Chris@0:         urlError();
Chris@0:       if (this.isNew()) return base;
Chris@0:       var id = this.get(this.idAttribute);
Chris@0:       return base.replace(/[^\/]$/, '$&/') + encodeURIComponent(id);
Chris@0:     },
Chris@0: 
Chris@0:     // **parse** converts a response into the hash of attributes to be `set` on
Chris@0:     // the model. The default implementation is just to pass the response along.
Chris@0:     parse: function(resp, options) {
Chris@0:       return resp;
Chris@0:     },
Chris@0: 
Chris@0:     // Create a new model with identical attributes to this one.
Chris@0:     clone: function() {
Chris@0:       return new this.constructor(this.attributes);
Chris@0:     },
Chris@0: 
Chris@0:     // A model is new if it has never been saved to the server, and lacks an id.
Chris@0:     isNew: function() {
Chris@0:       return !this.has(this.idAttribute);
Chris@0:     },
Chris@0: 
Chris@0:     // Check if the model is currently in a valid state.
Chris@0:     isValid: function(options) {
Chris@0:       return this._validate({}, _.defaults({validate: true}, options));
Chris@0:     },
Chris@0: 
Chris@0:     // Run validation against the next complete set of model attributes,
Chris@0:     // returning `true` if all is well. Otherwise, fire an `"invalid"` event.
Chris@0:     _validate: function(attrs, options) {
Chris@0:       if (!options.validate || !this.validate) return true;
Chris@0:       attrs = _.extend({}, this.attributes, attrs);
Chris@0:       var error = this.validationError = this.validate(attrs, options) || null;
Chris@0:       if (!error) return true;
Chris@0:       this.trigger('invalid', this, error, _.extend(options, {validationError: error}));
Chris@0:       return false;
Chris@0:     }
Chris@0: 
Chris@0:   });
Chris@0: 
Chris@0:   // Underscore methods that we want to implement on the Model, mapped to the
Chris@0:   // number of arguments they take.
Chris@0:   var modelMethods = { keys: 1, values: 1, pairs: 1, invert: 1, pick: 0,
Chris@0:       omit: 0, chain: 1, isEmpty: 1 };
Chris@0: 
Chris@0:   // Mix in each Underscore method as a proxy to `Model#attributes`.
Chris@0:   addUnderscoreMethods(Model, modelMethods, 'attributes');
Chris@0: 
Chris@0:   // Backbone.Collection
Chris@0:   // -------------------
Chris@0: 
Chris@0:   // If models tend to represent a single row of data, a Backbone Collection is
Chris@0:   // more analogous to a table full of data ... or a small slice or page of that
Chris@0:   // table, or a collection of rows that belong together for a particular reason
Chris@0:   // -- all of the messages in this particular folder, all of the documents
Chris@0:   // belonging to this particular author, and so on. Collections maintain
Chris@0:   // indexes of their models, both in order, and for lookup by `id`.
Chris@0: 
Chris@0:   // Create a new **Collection**, perhaps to contain a specific type of `model`.
Chris@0:   // If a `comparator` is specified, the Collection will maintain
Chris@0:   // its models in sort order, as they're added and removed.
Chris@0:   var Collection = Backbone.Collection = function(models, options) {
Chris@0:     options || (options = {});
Chris@0:     if (options.model) this.model = options.model;
Chris@0:     if (options.comparator !== void 0) this.comparator = options.comparator;
Chris@0:     this._reset();
Chris@0:     this.initialize.apply(this, arguments);
Chris@0:     if (models) this.reset(models, _.extend({silent: true}, options));
Chris@0:   };
Chris@0: 
Chris@0:   // Default options for `Collection#set`.
Chris@0:   var setOptions = {add: true, remove: true, merge: true};
Chris@0:   var addOptions = {add: true, remove: false};
Chris@0: 
Chris@0:   // Splices `insert` into `array` at index `at`.
Chris@0:   var splice = function(array, insert, at) {
Chris@0:     at = Math.min(Math.max(at, 0), array.length);
Chris@0:     var tail = Array(array.length - at);
Chris@0:     var length = insert.length;
Chris@0:     for (var i = 0; i < tail.length; i++) tail[i] = array[i + at];
Chris@0:     for (i = 0; i < length; i++) array[i + at] = insert[i];
Chris@0:     for (i = 0; i < tail.length; i++) array[i + length + at] = tail[i];
Chris@0:   };
Chris@0: 
Chris@0:   // Define the Collection's inheritable methods.
Chris@0:   _.extend(Collection.prototype, Events, {
Chris@0: 
Chris@0:     // The default model for a collection is just a **Backbone.Model**.
Chris@0:     // This should be overridden in most cases.
Chris@0:     model: Model,
Chris@0: 
Chris@0:     // Initialize is an empty function by default. Override it with your own
Chris@0:     // initialization logic.
Chris@0:     initialize: function(){},
Chris@0: 
Chris@0:     // The JSON representation of a Collection is an array of the
Chris@0:     // models' attributes.
Chris@0:     toJSON: function(options) {
Chris@0:       return this.map(function(model) { return model.toJSON(options); });
Chris@0:     },
Chris@0: 
Chris@0:     // Proxy `Backbone.sync` by default.
Chris@0:     sync: function() {
Chris@0:       return Backbone.sync.apply(this, arguments);
Chris@0:     },
Chris@0: 
Chris@0:     // Add a model, or list of models to the set. `models` may be Backbone
Chris@0:     // Models or raw JavaScript objects to be converted to Models, or any
Chris@0:     // combination of the two.
Chris@0:     add: function(models, options) {
Chris@0:       return this.set(models, _.extend({merge: false}, options, addOptions));
Chris@0:     },
Chris@0: 
Chris@0:     // Remove a model, or a list of models from the set.
Chris@0:     remove: function(models, options) {
Chris@0:       options = _.extend({}, options);
Chris@0:       var singular = !_.isArray(models);
Chris@0:       models = singular ? [models] : _.clone(models);
Chris@0:       var removed = this._removeModels(models, options);
Chris@0:       if (!options.silent && removed) this.trigger('update', this, options);
Chris@0:       return singular ? removed[0] : removed;
Chris@0:     },
Chris@0: 
Chris@0:     // Update a collection by `set`-ing a new list of models, adding new ones,
Chris@0:     // removing models that are no longer present, and merging models that
Chris@0:     // already exist in the collection, as necessary. Similar to **Model#set**,
Chris@0:     // the core operation for updating the data contained by the collection.
Chris@0:     set: function(models, options) {
Chris@0:       if (models == null) return;
Chris@0: 
Chris@0:       options = _.defaults({}, options, setOptions);
Chris@0:       if (options.parse && !this._isModel(models)) models = this.parse(models, options);
Chris@0: 
Chris@0:       var singular = !_.isArray(models);
Chris@0:       models = singular ? [models] : models.slice();
Chris@0: 
Chris@0:       var at = options.at;
Chris@0:       if (at != null) at = +at;
Chris@0:       if (at < 0) at += this.length + 1;
Chris@0: 
Chris@0:       var set = [];
Chris@0:       var toAdd = [];
Chris@0:       var toRemove = [];
Chris@0:       var modelMap = {};
Chris@0: 
Chris@0:       var add = options.add;
Chris@0:       var merge = options.merge;
Chris@0:       var remove = options.remove;
Chris@0: 
Chris@0:       var sort = false;
Chris@0:       var sortable = this.comparator && (at == null) && options.sort !== false;
Chris@0:       var sortAttr = _.isString(this.comparator) ? this.comparator : null;
Chris@0: 
Chris@0:       // Turn bare objects into model references, and prevent invalid models
Chris@0:       // from being added.
Chris@0:       var model;
Chris@0:       for (var i = 0; i < models.length; i++) {
Chris@0:         model = models[i];
Chris@0: 
Chris@0:         // If a duplicate is found, prevent it from being added and
Chris@0:         // optionally merge it into the existing model.
Chris@0:         var existing = this.get(model);
Chris@0:         if (existing) {
Chris@0:           if (merge && model !== existing) {
Chris@0:             var attrs = this._isModel(model) ? model.attributes : model;
Chris@0:             if (options.parse) attrs = existing.parse(attrs, options);
Chris@0:             existing.set(attrs, options);
Chris@0:             if (sortable && !sort) sort = existing.hasChanged(sortAttr);
Chris@0:           }
Chris@0:           if (!modelMap[existing.cid]) {
Chris@0:             modelMap[existing.cid] = true;
Chris@0:             set.push(existing);
Chris@0:           }
Chris@0:           models[i] = existing;
Chris@0: 
Chris@0:         // If this is a new, valid model, push it to the `toAdd` list.
Chris@0:         } else if (add) {
Chris@0:           model = models[i] = this._prepareModel(model, options);
Chris@0:           if (model) {
Chris@0:             toAdd.push(model);
Chris@0:             this._addReference(model, options);
Chris@0:             modelMap[model.cid] = true;
Chris@0:             set.push(model);
Chris@0:           }
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       // Remove stale models.
Chris@0:       if (remove) {
Chris@0:         for (i = 0; i < this.length; i++) {
Chris@0:           model = this.models[i];
Chris@0:           if (!modelMap[model.cid]) toRemove.push(model);
Chris@0:         }
Chris@0:         if (toRemove.length) this._removeModels(toRemove, options);
Chris@0:       }
Chris@0: 
Chris@0:       // See if sorting is needed, update `length` and splice in new models.
Chris@0:       var orderChanged = false;
Chris@0:       var replace = !sortable && add && remove;
Chris@0:       if (set.length && replace) {
Chris@0:         orderChanged = this.length != set.length || _.some(this.models, function(model, index) {
Chris@0:           return model !== set[index];
Chris@0:         });
Chris@0:         this.models.length = 0;
Chris@0:         splice(this.models, set, 0);
Chris@0:         this.length = this.models.length;
Chris@0:       } else if (toAdd.length) {
Chris@0:         if (sortable) sort = true;
Chris@0:         splice(this.models, toAdd, at == null ? this.length : at);
Chris@0:         this.length = this.models.length;
Chris@0:       }
Chris@0: 
Chris@0:       // Silently sort the collection if appropriate.
Chris@0:       if (sort) this.sort({silent: true});
Chris@0: 
Chris@0:       // Unless silenced, it's time to fire all appropriate add/sort events.
Chris@0:       if (!options.silent) {
Chris@0:         for (i = 0; i < toAdd.length; i++) {
Chris@0:           if (at != null) options.index = at + i;
Chris@0:           model = toAdd[i];
Chris@0:           model.trigger('add', model, this, options);
Chris@0:         }
Chris@0:         if (sort || orderChanged) this.trigger('sort', this, options);
Chris@0:         if (toAdd.length || toRemove.length) this.trigger('update', this, options);
Chris@0:       }
Chris@0: 
Chris@0:       // Return the added (or merged) model (or models).
Chris@0:       return singular ? models[0] : models;
Chris@0:     },
Chris@0: 
Chris@0:     // When you have more items than you want to add or remove individually,
Chris@0:     // you can reset the entire set with a new list of models, without firing
Chris@0:     // any granular `add` or `remove` events. Fires `reset` when finished.
Chris@0:     // Useful for bulk operations and optimizations.
Chris@0:     reset: function(models, options) {
Chris@0:       options = options ? _.clone(options) : {};
Chris@0:       for (var i = 0; i < this.models.length; i++) {
Chris@0:         this._removeReference(this.models[i], options);
Chris@0:       }
Chris@0:       options.previousModels = this.models;
Chris@0:       this._reset();
Chris@0:       models = this.add(models, _.extend({silent: true}, options));
Chris@0:       if (!options.silent) this.trigger('reset', this, options);
Chris@0:       return models;
Chris@0:     },
Chris@0: 
Chris@0:     // Add a model to the end of the collection.
Chris@0:     push: function(model, options) {
Chris@0:       return this.add(model, _.extend({at: this.length}, options));
Chris@0:     },
Chris@0: 
Chris@0:     // Remove a model from the end of the collection.
Chris@0:     pop: function(options) {
Chris@0:       var model = this.at(this.length - 1);
Chris@0:       return this.remove(model, options);
Chris@0:     },
Chris@0: 
Chris@0:     // Add a model to the beginning of the collection.
Chris@0:     unshift: function(model, options) {
Chris@0:       return this.add(model, _.extend({at: 0}, options));
Chris@0:     },
Chris@0: 
Chris@0:     // Remove a model from the beginning of the collection.
Chris@0:     shift: function(options) {
Chris@0:       var model = this.at(0);
Chris@0:       return this.remove(model, options);
Chris@0:     },
Chris@0: 
Chris@0:     // Slice out a sub-array of models from the collection.
Chris@0:     slice: function() {
Chris@0:       return slice.apply(this.models, arguments);
Chris@0:     },
Chris@0: 
Chris@0:     // Get a model from the set by id.
Chris@0:     get: function(obj) {
Chris@0:       if (obj == null) return void 0;
Chris@0:       var id = this.modelId(this._isModel(obj) ? obj.attributes : obj);
Chris@0:       return this._byId[obj] || this._byId[id] || this._byId[obj.cid];
Chris@0:     },
Chris@0: 
Chris@0:     // Get the model at the given index.
Chris@0:     at: function(index) {
Chris@0:       if (index < 0) index += this.length;
Chris@0:       return this.models[index];
Chris@0:     },
Chris@0: 
Chris@0:     // Return models with matching attributes. Useful for simple cases of
Chris@0:     // `filter`.
Chris@0:     where: function(attrs, first) {
Chris@0:       return this[first ? 'find' : 'filter'](attrs);
Chris@0:     },
Chris@0: 
Chris@0:     // Return the first model with matching attributes. Useful for simple cases
Chris@0:     // of `find`.
Chris@0:     findWhere: function(attrs) {
Chris@0:       return this.where(attrs, true);
Chris@0:     },
Chris@0: 
Chris@0:     // Force the collection to re-sort itself. You don't need to call this under
Chris@0:     // normal circumstances, as the set will maintain sort order as each item
Chris@0:     // is added.
Chris@0:     sort: function(options) {
Chris@0:       var comparator = this.comparator;
Chris@0:       if (!comparator) throw new Error('Cannot sort a set without a comparator');
Chris@0:       options || (options = {});
Chris@0: 
Chris@0:       var length = comparator.length;
Chris@0:       if (_.isFunction(comparator)) comparator = _.bind(comparator, this);
Chris@0: 
Chris@0:       // Run sort based on type of `comparator`.
Chris@0:       if (length === 1 || _.isString(comparator)) {
Chris@0:         this.models = this.sortBy(comparator);
Chris@0:       } else {
Chris@0:         this.models.sort(comparator);
Chris@0:       }
Chris@0:       if (!options.silent) this.trigger('sort', this, options);
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Pluck an attribute from each model in the collection.
Chris@0:     pluck: function(attr) {
Chris@0:       return _.invoke(this.models, 'get', attr);
Chris@0:     },
Chris@0: 
Chris@0:     // Fetch the default set of models for this collection, resetting the
Chris@0:     // collection when they arrive. If `reset: true` is passed, the response
Chris@0:     // data will be passed through the `reset` method instead of `set`.
Chris@0:     fetch: function(options) {
Chris@0:       options = _.extend({parse: true}, options);
Chris@0:       var success = options.success;
Chris@0:       var collection = this;
Chris@0:       options.success = function(resp) {
Chris@0:         var method = options.reset ? 'reset' : 'set';
Chris@0:         collection[method](resp, options);
Chris@0:         if (success) success.call(options.context, collection, resp, options);
Chris@0:         collection.trigger('sync', collection, resp, options);
Chris@0:       };
Chris@0:       wrapError(this, options);
Chris@0:       return this.sync('read', this, options);
Chris@0:     },
Chris@0: 
Chris@0:     // Create a new instance of a model in this collection. Add the model to the
Chris@0:     // collection immediately, unless `wait: true` is passed, in which case we
Chris@0:     // wait for the server to agree.
Chris@0:     create: function(model, options) {
Chris@0:       options = options ? _.clone(options) : {};
Chris@0:       var wait = options.wait;
Chris@0:       model = this._prepareModel(model, options);
Chris@0:       if (!model) return false;
Chris@0:       if (!wait) this.add(model, options);
Chris@0:       var collection = this;
Chris@0:       var success = options.success;
Chris@0:       options.success = function(model, resp, callbackOpts) {
Chris@0:         if (wait) collection.add(model, callbackOpts);
Chris@0:         if (success) success.call(callbackOpts.context, model, resp, callbackOpts);
Chris@0:       };
Chris@0:       model.save(null, options);
Chris@0:       return model;
Chris@0:     },
Chris@0: 
Chris@0:     // **parse** converts a response into a list of models to be added to the
Chris@0:     // collection. The default implementation is just to pass it through.
Chris@0:     parse: function(resp, options) {
Chris@0:       return resp;
Chris@0:     },
Chris@0: 
Chris@0:     // Create a new collection with an identical list of models as this one.
Chris@0:     clone: function() {
Chris@0:       return new this.constructor(this.models, {
Chris@0:         model: this.model,
Chris@0:         comparator: this.comparator
Chris@0:       });
Chris@0:     },
Chris@0: 
Chris@0:     // Define how to uniquely identify models in the collection.
Chris@0:     modelId: function (attrs) {
Chris@0:       return attrs[this.model.prototype.idAttribute || 'id'];
Chris@0:     },
Chris@0: 
Chris@0:     // Private method to reset all internal state. Called when the collection
Chris@0:     // is first initialized or reset.
Chris@0:     _reset: function() {
Chris@0:       this.length = 0;
Chris@0:       this.models = [];
Chris@0:       this._byId  = {};
Chris@0:     },
Chris@0: 
Chris@0:     // Prepare a hash of attributes (or other model) to be added to this
Chris@0:     // collection.
Chris@0:     _prepareModel: function(attrs, options) {
Chris@0:       if (this._isModel(attrs)) {
Chris@0:         if (!attrs.collection) attrs.collection = this;
Chris@0:         return attrs;
Chris@0:       }
Chris@0:       options = options ? _.clone(options) : {};
Chris@0:       options.collection = this;
Chris@0:       var model = new this.model(attrs, options);
Chris@0:       if (!model.validationError) return model;
Chris@0:       this.trigger('invalid', this, model.validationError, options);
Chris@0:       return false;
Chris@0:     },
Chris@0: 
Chris@0:     // Internal method called by both remove and set.
Chris@0:     _removeModels: function(models, options) {
Chris@0:       var removed = [];
Chris@0:       for (var i = 0; i < models.length; i++) {
Chris@0:         var model = this.get(models[i]);
Chris@0:         if (!model) continue;
Chris@0: 
Chris@0:         var index = this.indexOf(model);
Chris@0:         this.models.splice(index, 1);
Chris@0:         this.length--;
Chris@0: 
Chris@0:         if (!options.silent) {
Chris@0:           options.index = index;
Chris@0:           model.trigger('remove', model, this, options);
Chris@0:         }
Chris@0: 
Chris@0:         removed.push(model);
Chris@0:         this._removeReference(model, options);
Chris@0:       }
Chris@0:       return removed.length ? removed : false;
Chris@0:     },
Chris@0: 
Chris@0:     // Method for checking whether an object should be considered a model for
Chris@0:     // the purposes of adding to the collection.
Chris@0:     _isModel: function (model) {
Chris@0:       return model instanceof Model;
Chris@0:     },
Chris@0: 
Chris@0:     // Internal method to create a model's ties to a collection.
Chris@0:     _addReference: function(model, options) {
Chris@0:       this._byId[model.cid] = model;
Chris@0:       var id = this.modelId(model.attributes);
Chris@0:       if (id != null) this._byId[id] = model;
Chris@0:       model.on('all', this._onModelEvent, this);
Chris@0:     },
Chris@0: 
Chris@0:     // Internal method to sever a model's ties to a collection.
Chris@0:     _removeReference: function(model, options) {
Chris@0:       delete this._byId[model.cid];
Chris@0:       var id = this.modelId(model.attributes);
Chris@0:       if (id != null) delete this._byId[id];
Chris@0:       if (this === model.collection) delete model.collection;
Chris@0:       model.off('all', this._onModelEvent, this);
Chris@0:     },
Chris@0: 
Chris@0:     // Internal method called every time a model in the set fires an event.
Chris@0:     // Sets need to update their indexes when models change ids. All other
Chris@0:     // events simply proxy through. "add" and "remove" events that originate
Chris@0:     // in other collections are ignored.
Chris@0:     _onModelEvent: function(event, model, collection, options) {
Chris@0:       if ((event === 'add' || event === 'remove') && collection !== this) return;
Chris@0:       if (event === 'destroy') this.remove(model, options);
Chris@0:       if (event === 'change') {
Chris@0:         var prevId = this.modelId(model.previousAttributes());
Chris@0:         var id = this.modelId(model.attributes);
Chris@0:         if (prevId !== id) {
Chris@0:           if (prevId != null) delete this._byId[prevId];
Chris@0:           if (id != null) this._byId[id] = model;
Chris@0:         }
Chris@0:       }
Chris@0:       this.trigger.apply(this, arguments);
Chris@0:     }
Chris@0: 
Chris@0:   });
Chris@0: 
Chris@0:   // Underscore methods that we want to implement on the Collection.
Chris@0:   // 90% of the core usefulness of Backbone Collections is actually implemented
Chris@0:   // right here:
Chris@0:   var collectionMethods = { forEach: 3, each: 3, map: 3, collect: 3, reduce: 4,
Chris@0:       foldl: 4, inject: 4, reduceRight: 4, foldr: 4, find: 3, detect: 3, filter: 3,
Chris@0:       select: 3, reject: 3, every: 3, all: 3, some: 3, any: 3, include: 3, includes: 3,
Chris@0:       contains: 3, invoke: 0, max: 3, min: 3, toArray: 1, size: 1, first: 3,
Chris@0:       head: 3, take: 3, initial: 3, rest: 3, tail: 3, drop: 3, last: 3,
Chris@0:       without: 0, difference: 0, indexOf: 3, shuffle: 1, lastIndexOf: 3,
Chris@0:       isEmpty: 1, chain: 1, sample: 3, partition: 3, groupBy: 3, countBy: 3,
Chris@0:       sortBy: 3, indexBy: 3};
Chris@0: 
Chris@0:   // Mix in each Underscore method as a proxy to `Collection#models`.
Chris@0:   addUnderscoreMethods(Collection, collectionMethods, 'models');
Chris@0: 
Chris@0:   // Backbone.View
Chris@0:   // -------------
Chris@0: 
Chris@0:   // Backbone Views are almost more convention than they are actual code. A View
Chris@0:   // is simply a JavaScript object that represents a logical chunk of UI in the
Chris@0:   // DOM. This might be a single item, an entire list, a sidebar or panel, or
Chris@0:   // even the surrounding frame which wraps your whole app. Defining a chunk of
Chris@0:   // UI as a **View** allows you to define your DOM events declaratively, without
Chris@0:   // having to worry about render order ... and makes it easy for the view to
Chris@0:   // react to specific changes in the state of your models.
Chris@0: 
Chris@0:   // Creating a Backbone.View creates its initial element outside of the DOM,
Chris@0:   // if an existing element is not provided...
Chris@0:   var View = Backbone.View = function(options) {
Chris@0:     this.cid = _.uniqueId('view');
Chris@0:     _.extend(this, _.pick(options, viewOptions));
Chris@0:     this._ensureElement();
Chris@0:     this.initialize.apply(this, arguments);
Chris@0:   };
Chris@0: 
Chris@0:   // Cached regex to split keys for `delegate`.
Chris@0:   var delegateEventSplitter = /^(\S+)\s*(.*)$/;
Chris@0: 
Chris@0:   // List of view options to be set as properties.
Chris@0:   var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName', 'events'];
Chris@0: 
Chris@0:   // Set up all inheritable **Backbone.View** properties and methods.
Chris@0:   _.extend(View.prototype, Events, {
Chris@0: 
Chris@0:     // The default `tagName` of a View's element is `"div"`.
Chris@0:     tagName: 'div',
Chris@0: 
Chris@0:     // jQuery delegate for element lookup, scoped to DOM elements within the
Chris@0:     // current view. This should be preferred to global lookups where possible.
Chris@0:     $: function(selector) {
Chris@0:       return this.$el.find(selector);
Chris@0:     },
Chris@0: 
Chris@0:     // Initialize is an empty function by default. Override it with your own
Chris@0:     // initialization logic.
Chris@0:     initialize: function(){},
Chris@0: 
Chris@0:     // **render** is the core function that your view should override, in order
Chris@0:     // to populate its element (`this.el`), with the appropriate HTML. The
Chris@0:     // convention is for **render** to always return `this`.
Chris@0:     render: function() {
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Remove this view by taking the element out of the DOM, and removing any
Chris@0:     // applicable Backbone.Events listeners.
Chris@0:     remove: function() {
Chris@0:       this._removeElement();
Chris@0:       this.stopListening();
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Remove this view's element from the document and all event listeners
Chris@0:     // attached to it. Exposed for subclasses using an alternative DOM
Chris@0:     // manipulation API.
Chris@0:     _removeElement: function() {
Chris@0:       this.$el.remove();
Chris@0:     },
Chris@0: 
Chris@0:     // Change the view's element (`this.el` property) and re-delegate the
Chris@0:     // view's events on the new element.
Chris@0:     setElement: function(element) {
Chris@0:       this.undelegateEvents();
Chris@0:       this._setElement(element);
Chris@0:       this.delegateEvents();
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Creates the `this.el` and `this.$el` references for this view using the
Chris@0:     // given `el`. `el` can be a CSS selector or an HTML string, a jQuery
Chris@0:     // context or an element. Subclasses can override this to utilize an
Chris@0:     // alternative DOM manipulation API and are only required to set the
Chris@0:     // `this.el` property.
Chris@0:     _setElement: function(el) {
Chris@0:       this.$el = el instanceof Backbone.$ ? el : Backbone.$(el);
Chris@0:       this.el = this.$el[0];
Chris@0:     },
Chris@0: 
Chris@0:     // Set callbacks, where `this.events` is a hash of
Chris@0:     //
Chris@0:     // *{"event selector": "callback"}*
Chris@0:     //
Chris@0:     //     {
Chris@0:     //       'mousedown .title':  'edit',
Chris@0:     //       'click .button':     'save',
Chris@0:     //       'click .open':       function(e) { ... }
Chris@0:     //     }
Chris@0:     //
Chris@0:     // pairs. Callbacks will be bound to the view, with `this` set properly.
Chris@0:     // Uses event delegation for efficiency.
Chris@0:     // Omitting the selector binds the event to `this.el`.
Chris@0:     delegateEvents: function(events) {
Chris@0:       events || (events = _.result(this, 'events'));
Chris@0:       if (!events) return this;
Chris@0:       this.undelegateEvents();
Chris@0:       for (var key in events) {
Chris@0:         var method = events[key];
Chris@0:         if (!_.isFunction(method)) method = this[method];
Chris@0:         if (!method) continue;
Chris@0:         var match = key.match(delegateEventSplitter);
Chris@0:         this.delegate(match[1], match[2], _.bind(method, this));
Chris@0:       }
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Add a single event listener to the view's element (or a child element
Chris@0:     // using `selector`). This only works for delegate-able events: not `focus`,
Chris@0:     // `blur`, and not `change`, `submit`, and `reset` in Internet Explorer.
Chris@0:     delegate: function(eventName, selector, listener) {
Chris@0:       this.$el.on(eventName + '.delegateEvents' + this.cid, selector, listener);
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Clears all callbacks previously bound to the view by `delegateEvents`.
Chris@0:     // You usually don't need to use this, but may wish to if you have multiple
Chris@0:     // Backbone views attached to the same DOM element.
Chris@0:     undelegateEvents: function() {
Chris@0:       if (this.$el) this.$el.off('.delegateEvents' + this.cid);
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // A finer-grained `undelegateEvents` for removing a single delegated event.
Chris@0:     // `selector` and `listener` are both optional.
Chris@0:     undelegate: function(eventName, selector, listener) {
Chris@0:       this.$el.off(eventName + '.delegateEvents' + this.cid, selector, listener);
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Produces a DOM element to be assigned to your view. Exposed for
Chris@0:     // subclasses using an alternative DOM manipulation API.
Chris@0:     _createElement: function(tagName) {
Chris@0:       return document.createElement(tagName);
Chris@0:     },
Chris@0: 
Chris@0:     // Ensure that the View has a DOM element to render into.
Chris@0:     // If `this.el` is a string, pass it through `$()`, take the first
Chris@0:     // matching element, and re-assign it to `el`. Otherwise, create
Chris@0:     // an element from the `id`, `className` and `tagName` properties.
Chris@0:     _ensureElement: function() {
Chris@0:       if (!this.el) {
Chris@0:         var attrs = _.extend({}, _.result(this, 'attributes'));
Chris@0:         if (this.id) attrs.id = _.result(this, 'id');
Chris@0:         if (this.className) attrs['class'] = _.result(this, 'className');
Chris@0:         this.setElement(this._createElement(_.result(this, 'tagName')));
Chris@0:         this._setAttributes(attrs);
Chris@0:       } else {
Chris@0:         this.setElement(_.result(this, 'el'));
Chris@0:       }
Chris@0:     },
Chris@0: 
Chris@0:     // Set attributes from a hash on this view's element.  Exposed for
Chris@0:     // subclasses using an alternative DOM manipulation API.
Chris@0:     _setAttributes: function(attributes) {
Chris@0:       this.$el.attr(attributes);
Chris@0:     }
Chris@0: 
Chris@0:   });
Chris@0: 
Chris@0:   // Backbone.sync
Chris@0:   // -------------
Chris@0: 
Chris@0:   // Override this function to change the manner in which Backbone persists
Chris@0:   // models to the server. You will be passed the type of request, and the
Chris@0:   // model in question. By default, makes a RESTful Ajax request
Chris@0:   // to the model's `url()`. Some possible customizations could be:
Chris@0:   //
Chris@0:   // * Use `setTimeout` to batch rapid-fire updates into a single request.
Chris@0:   // * Send up the models as XML instead of JSON.
Chris@0:   // * Persist models via WebSockets instead of Ajax.
Chris@0:   //
Chris@0:   // Turn on `Backbone.emulateHTTP` in order to send `PUT` and `DELETE` requests
Chris@0:   // as `POST`, with a `_method` parameter containing the true HTTP method,
Chris@0:   // as well as all requests with the body as `application/x-www-form-urlencoded`
Chris@0:   // instead of `application/json` with the model in a param named `model`.
Chris@0:   // Useful when interfacing with server-side languages like **PHP** that make
Chris@0:   // it difficult to read the body of `PUT` requests.
Chris@0:   Backbone.sync = function(method, model, options) {
Chris@0:     var type = methodMap[method];
Chris@0: 
Chris@0:     // Default options, unless specified.
Chris@0:     _.defaults(options || (options = {}), {
Chris@0:       emulateHTTP: Backbone.emulateHTTP,
Chris@0:       emulateJSON: Backbone.emulateJSON
Chris@0:     });
Chris@0: 
Chris@0:     // Default JSON-request options.
Chris@0:     var params = {type: type, dataType: 'json'};
Chris@0: 
Chris@0:     // Ensure that we have a URL.
Chris@0:     if (!options.url) {
Chris@0:       params.url = _.result(model, 'url') || urlError();
Chris@0:     }
Chris@0: 
Chris@0:     // Ensure that we have the appropriate request data.
Chris@0:     if (options.data == null && model && (method === 'create' || method === 'update' || method === 'patch')) {
Chris@0:       params.contentType = 'application/json';
Chris@0:       params.data = JSON.stringify(options.attrs || model.toJSON(options));
Chris@0:     }
Chris@0: 
Chris@0:     // For older servers, emulate JSON by encoding the request into an HTML-form.
Chris@0:     if (options.emulateJSON) {
Chris@0:       params.contentType = 'application/x-www-form-urlencoded';
Chris@0:       params.data = params.data ? {model: params.data} : {};
Chris@0:     }
Chris@0: 
Chris@0:     // For older servers, emulate HTTP by mimicking the HTTP method with `_method`
Chris@0:     // And an `X-HTTP-Method-Override` header.
Chris@0:     if (options.emulateHTTP && (type === 'PUT' || type === 'DELETE' || type === 'PATCH')) {
Chris@0:       params.type = 'POST';
Chris@0:       if (options.emulateJSON) params.data._method = type;
Chris@0:       var beforeSend = options.beforeSend;
Chris@0:       options.beforeSend = function(xhr) {
Chris@0:         xhr.setRequestHeader('X-HTTP-Method-Override', type);
Chris@0:         if (beforeSend) return beforeSend.apply(this, arguments);
Chris@0:       };
Chris@0:     }
Chris@0: 
Chris@0:     // Don't process data on a non-GET request.
Chris@0:     if (params.type !== 'GET' && !options.emulateJSON) {
Chris@0:       params.processData = false;
Chris@0:     }
Chris@0: 
Chris@0:     // Pass along `textStatus` and `errorThrown` from jQuery.
Chris@0:     var error = options.error;
Chris@0:     options.error = function(xhr, textStatus, errorThrown) {
Chris@0:       options.textStatus = textStatus;
Chris@0:       options.errorThrown = errorThrown;
Chris@0:       if (error) error.call(options.context, xhr, textStatus, errorThrown);
Chris@0:     };
Chris@0: 
Chris@0:     // Make the request, allowing the user to override any Ajax options.
Chris@0:     var xhr = options.xhr = Backbone.ajax(_.extend(params, options));
Chris@0:     model.trigger('request', model, xhr, options);
Chris@0:     return xhr;
Chris@0:   };
Chris@0: 
Chris@0:   // Map from CRUD to HTTP for our default `Backbone.sync` implementation.
Chris@0:   var methodMap = {
Chris@0:     'create': 'POST',
Chris@0:     'update': 'PUT',
Chris@0:     'patch':  'PATCH',
Chris@0:     'delete': 'DELETE',
Chris@0:     'read':   'GET'
Chris@0:   };
Chris@0: 
Chris@0:   // Set the default implementation of `Backbone.ajax` to proxy through to `$`.
Chris@0:   // Override this if you'd like to use a different library.
Chris@0:   Backbone.ajax = function() {
Chris@0:     return Backbone.$.ajax.apply(Backbone.$, arguments);
Chris@0:   };
Chris@0: 
Chris@0:   // Backbone.Router
Chris@0:   // ---------------
Chris@0: 
Chris@0:   // Routers map faux-URLs to actions, and fire events when routes are
Chris@0:   // matched. Creating a new one sets its `routes` hash, if not set statically.
Chris@0:   var Router = Backbone.Router = function(options) {
Chris@0:     options || (options = {});
Chris@0:     if (options.routes) this.routes = options.routes;
Chris@0:     this._bindRoutes();
Chris@0:     this.initialize.apply(this, arguments);
Chris@0:   };
Chris@0: 
Chris@0:   // Cached regular expressions for matching named param parts and splatted
Chris@0:   // parts of route strings.
Chris@0:   var optionalParam = /\((.*?)\)/g;
Chris@0:   var namedParam    = /(\(\?)?:\w+/g;
Chris@0:   var splatParam    = /\*\w+/g;
Chris@0:   var escapeRegExp  = /[\-{}\[\]+?.,\\\^$|#\s]/g;
Chris@0: 
Chris@0:   // Set up all inheritable **Backbone.Router** properties and methods.
Chris@0:   _.extend(Router.prototype, Events, {
Chris@0: 
Chris@0:     // Initialize is an empty function by default. Override it with your own
Chris@0:     // initialization logic.
Chris@0:     initialize: function(){},
Chris@0: 
Chris@0:     // Manually bind a single named route to a callback. For example:
Chris@0:     //
Chris@0:     //     this.route('search/:query/p:num', 'search', function(query, num) {
Chris@0:     //       ...
Chris@0:     //     });
Chris@0:     //
Chris@0:     route: function(route, name, callback) {
Chris@0:       if (!_.isRegExp(route)) route = this._routeToRegExp(route);
Chris@0:       if (_.isFunction(name)) {
Chris@0:         callback = name;
Chris@0:         name = '';
Chris@0:       }
Chris@0:       if (!callback) callback = this[name];
Chris@0:       var router = this;
Chris@0:       Backbone.history.route(route, function(fragment) {
Chris@0:         var args = router._extractParameters(route, fragment);
Chris@0:         if (router.execute(callback, args, name) !== false) {
Chris@0:           router.trigger.apply(router, ['route:' + name].concat(args));
Chris@0:           router.trigger('route', name, args);
Chris@0:           Backbone.history.trigger('route', router, name, args);
Chris@0:         }
Chris@0:       });
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Execute a route handler with the provided parameters.  This is an
Chris@0:     // excellent place to do pre-route setup or post-route cleanup.
Chris@0:     execute: function(callback, args, name) {
Chris@0:       if (callback) callback.apply(this, args);
Chris@0:     },
Chris@0: 
Chris@0:     // Simple proxy to `Backbone.history` to save a fragment into the history.
Chris@0:     navigate: function(fragment, options) {
Chris@0:       Backbone.history.navigate(fragment, options);
Chris@0:       return this;
Chris@0:     },
Chris@0: 
Chris@0:     // Bind all defined routes to `Backbone.history`. We have to reverse the
Chris@0:     // order of the routes here to support behavior where the most general
Chris@0:     // routes can be defined at the bottom of the route map.
Chris@0:     _bindRoutes: function() {
Chris@0:       if (!this.routes) return;
Chris@0:       this.routes = _.result(this, 'routes');
Chris@0:       var route, routes = _.keys(this.routes);
Chris@0:       while ((route = routes.pop()) != null) {
Chris@0:         this.route(route, this.routes[route]);
Chris@0:       }
Chris@0:     },
Chris@0: 
Chris@0:     // Convert a route string into a regular expression, suitable for matching
Chris@0:     // against the current location hash.
Chris@0:     _routeToRegExp: function(route) {
Chris@0:       route = route.replace(escapeRegExp, '\\$&')
Chris@0:                    .replace(optionalParam, '(?:$1)?')
Chris@0:                    .replace(namedParam, function(match, optional) {
Chris@0:                      return optional ? match : '([^/?]+)';
Chris@0:                    })
Chris@0:                    .replace(splatParam, '([^?]*?)');
Chris@0:       return new RegExp('^' + route + '(?:\\?([\\s\\S]*))?$');
Chris@0:     },
Chris@0: 
Chris@0:     // Given a route, and a URL fragment that it matches, return the array of
Chris@0:     // extracted decoded parameters. Empty or unmatched parameters will be
Chris@0:     // treated as `null` to normalize cross-browser behavior.
Chris@0:     _extractParameters: function(route, fragment) {
Chris@0:       var params = route.exec(fragment).slice(1);
Chris@0:       return _.map(params, function(param, i) {
Chris@0:         // Don't decode the search params.
Chris@0:         if (i === params.length - 1) return param || null;
Chris@0:         return param ? decodeURIComponent(param) : null;
Chris@0:       });
Chris@0:     }
Chris@0: 
Chris@0:   });
Chris@0: 
Chris@0:   // Backbone.History
Chris@0:   // ----------------
Chris@0: 
Chris@0:   // Handles cross-browser history management, based on either
Chris@0:   // [pushState](http://diveintohtml5.info/history.html) and real URLs, or
Chris@0:   // [onhashchange](https://developer.mozilla.org/en-US/docs/DOM/window.onhashchange)
Chris@0:   // and URL fragments. If the browser supports neither (old IE, natch),
Chris@0:   // falls back to polling.
Chris@0:   var History = Backbone.History = function() {
Chris@0:     this.handlers = [];
Chris@0:     this.checkUrl = _.bind(this.checkUrl, this);
Chris@0: 
Chris@0:     // Ensure that `History` can be used outside of the browser.
Chris@0:     if (typeof window !== 'undefined') {
Chris@0:       this.location = window.location;
Chris@0:       this.history = window.history;
Chris@0:     }
Chris@0:   };
Chris@0: 
Chris@0:   // Cached regex for stripping a leading hash/slash and trailing space.
Chris@0:   var routeStripper = /^[#\/]|\s+$/g;
Chris@0: 
Chris@0:   // Cached regex for stripping leading and trailing slashes.
Chris@0:   var rootStripper = /^\/+|\/+$/g;
Chris@0: 
Chris@0:   // Cached regex for stripping urls of hash.
Chris@0:   var pathStripper = /#.*$/;
Chris@0: 
Chris@0:   // Has the history handling already been started?
Chris@0:   History.started = false;
Chris@0: 
Chris@0:   // Set up all inheritable **Backbone.History** properties and methods.
Chris@0:   _.extend(History.prototype, Events, {
Chris@0: 
Chris@0:     // The default interval to poll for hash changes, if necessary, is
Chris@0:     // twenty times a second.
Chris@0:     interval: 50,
Chris@0: 
Chris@0:     // Are we at the app root?
Chris@0:     atRoot: function() {
Chris@0:       var path = this.location.pathname.replace(/[^\/]$/, '$&/');
Chris@0:       return path === this.root && !this.getSearch();
Chris@0:     },
Chris@0: 
Chris@0:     // Does the pathname match the root?
Chris@0:     matchRoot: function() {
Chris@0:       var path = this.decodeFragment(this.location.pathname);
Chris@0:       var root = path.slice(0, this.root.length - 1) + '/';
Chris@0:       return root === this.root;
Chris@0:     },
Chris@0: 
Chris@0:     // Unicode characters in `location.pathname` are percent encoded so they're
Chris@0:     // decoded for comparison. `%25` should not be decoded since it may be part
Chris@0:     // of an encoded parameter.
Chris@0:     decodeFragment: function(fragment) {
Chris@0:       return decodeURI(fragment.replace(/%25/g, '%2525'));
Chris@0:     },
Chris@0: 
Chris@0:     // In IE6, the hash fragment and search params are incorrect if the
Chris@0:     // fragment contains `?`.
Chris@0:     getSearch: function() {
Chris@0:       var match = this.location.href.replace(/#.*/, '').match(/\?.+/);
Chris@0:       return match ? match[0] : '';
Chris@0:     },
Chris@0: 
Chris@0:     // Gets the true hash value. Cannot use location.hash directly due to bug
Chris@0:     // in Firefox where location.hash will always be decoded.
Chris@0:     getHash: function(window) {
Chris@0:       var match = (window || this).location.href.match(/#(.*)$/);
Chris@0:       return match ? match[1] : '';
Chris@0:     },
Chris@0: 
Chris@0:     // Get the pathname and search params, without the root.
Chris@0:     getPath: function() {
Chris@0:       var path = this.decodeFragment(
Chris@0:         this.location.pathname + this.getSearch()
Chris@0:       ).slice(this.root.length - 1);
Chris@0:       return path.charAt(0) === '/' ? path.slice(1) : path;
Chris@0:     },
Chris@0: 
Chris@0:     // Get the cross-browser normalized URL fragment from the path or hash.
Chris@0:     getFragment: function(fragment) {
Chris@0:       if (fragment == null) {
Chris@0:         if (this._usePushState || !this._wantsHashChange) {
Chris@0:           fragment = this.getPath();
Chris@0:         } else {
Chris@0:           fragment = this.getHash();
Chris@0:         }
Chris@0:       }
Chris@0:       return fragment.replace(routeStripper, '');
Chris@0:     },
Chris@0: 
Chris@0:     // Start the hash change handling, returning `true` if the current URL matches
Chris@0:     // an existing route, and `false` otherwise.
Chris@0:     start: function(options) {
Chris@0:       if (History.started) throw new Error('Backbone.history has already been started');
Chris@0:       History.started = true;
Chris@0: 
Chris@0:       // Figure out the initial configuration. Do we need an iframe?
Chris@0:       // Is pushState desired ... is it available?
Chris@0:       this.options          = _.extend({root: '/'}, this.options, options);
Chris@0:       this.root             = this.options.root;
Chris@0:       this._wantsHashChange = this.options.hashChange !== false;
Chris@0:       this._hasHashChange   = 'onhashchange' in window && (document.documentMode === void 0 || document.documentMode > 7);
Chris@0:       this._useHashChange   = this._wantsHashChange && this._hasHashChange;
Chris@0:       this._wantsPushState  = !!this.options.pushState;
Chris@0:       this._hasPushState    = !!(this.history && this.history.pushState);
Chris@0:       this._usePushState    = this._wantsPushState && this._hasPushState;
Chris@0:       this.fragment         = this.getFragment();
Chris@0: 
Chris@0:       // Normalize root to always include a leading and trailing slash.
Chris@0:       this.root = ('/' + this.root + '/').replace(rootStripper, '/');
Chris@0: 
Chris@0:       // Transition from hashChange to pushState or vice versa if both are
Chris@0:       // requested.
Chris@0:       if (this._wantsHashChange && this._wantsPushState) {
Chris@0: 
Chris@0:         // If we've started off with a route from a `pushState`-enabled
Chris@0:         // browser, but we're currently in a browser that doesn't support it...
Chris@0:         if (!this._hasPushState && !this.atRoot()) {
Chris@0:           var root = this.root.slice(0, -1) || '/';
Chris@0:           this.location.replace(root + '#' + this.getPath());
Chris@0:           // Return immediately as browser will do redirect to new url
Chris@0:           return true;
Chris@0: 
Chris@0:         // Or if we've started out with a hash-based route, but we're currently
Chris@0:         // in a browser where it could be `pushState`-based instead...
Chris@0:         } else if (this._hasPushState && this.atRoot()) {
Chris@0:           this.navigate(this.getHash(), {replace: true});
Chris@0:         }
Chris@0: 
Chris@0:       }
Chris@0: 
Chris@0:       // Proxy an iframe to handle location events if the browser doesn't
Chris@0:       // support the `hashchange` event, HTML5 history, or the user wants
Chris@0:       // `hashChange` but not `pushState`.
Chris@0:       if (!this._hasHashChange && this._wantsHashChange && !this._usePushState) {
Chris@0:         this.iframe = document.createElement('iframe');
Chris@0:         this.iframe.src = 'javascript:0';
Chris@0:         this.iframe.style.display = 'none';
Chris@0:         this.iframe.tabIndex = -1;
Chris@0:         var body = document.body;
Chris@0:         // Using `appendChild` will throw on IE < 9 if the document is not ready.
Chris@0:         var iWindow = body.insertBefore(this.iframe, body.firstChild).contentWindow;
Chris@0:         iWindow.document.open();
Chris@0:         iWindow.document.close();
Chris@0:         iWindow.location.hash = '#' + this.fragment;
Chris@0:       }
Chris@0: 
Chris@0:       // Add a cross-platform `addEventListener` shim for older browsers.
Chris@0:       var addEventListener = window.addEventListener || function (eventName, listener) {
Chris@0:         return attachEvent('on' + eventName, listener);
Chris@0:       };
Chris@0: 
Chris@0:       // Depending on whether we're using pushState or hashes, and whether
Chris@0:       // 'onhashchange' is supported, determine how we check the URL state.
Chris@0:       if (this._usePushState) {
Chris@0:         addEventListener('popstate', this.checkUrl, false);
Chris@0:       } else if (this._useHashChange && !this.iframe) {
Chris@0:         addEventListener('hashchange', this.checkUrl, false);
Chris@0:       } else if (this._wantsHashChange) {
Chris@0:         this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
Chris@0:       }
Chris@0: 
Chris@0:       if (!this.options.silent) return this.loadUrl();
Chris@0:     },
Chris@0: 
Chris@0:     // Disable Backbone.history, perhaps temporarily. Not useful in a real app,
Chris@0:     // but possibly useful for unit testing Routers.
Chris@0:     stop: function() {
Chris@0:       // Add a cross-platform `removeEventListener` shim for older browsers.
Chris@0:       var removeEventListener = window.removeEventListener || function (eventName, listener) {
Chris@0:         return detachEvent('on' + eventName, listener);
Chris@0:       };
Chris@0: 
Chris@0:       // Remove window listeners.
Chris@0:       if (this._usePushState) {
Chris@0:         removeEventListener('popstate', this.checkUrl, false);
Chris@0:       } else if (this._useHashChange && !this.iframe) {
Chris@0:         removeEventListener('hashchange', this.checkUrl, false);
Chris@0:       }
Chris@0: 
Chris@0:       // Clean up the iframe if necessary.
Chris@0:       if (this.iframe) {
Chris@0:         document.body.removeChild(this.iframe);
Chris@0:         this.iframe = null;
Chris@0:       }
Chris@0: 
Chris@0:       // Some environments will throw when clearing an undefined interval.
Chris@0:       if (this._checkUrlInterval) clearInterval(this._checkUrlInterval);
Chris@0:       History.started = false;
Chris@0:     },
Chris@0: 
Chris@0:     // Add a route to be tested when the fragment changes. Routes added later
Chris@0:     // may override previous routes.
Chris@0:     route: function(route, callback) {
Chris@0:       this.handlers.unshift({route: route, callback: callback});
Chris@0:     },
Chris@0: 
Chris@0:     // Checks the current URL to see if it has changed, and if it has,
Chris@0:     // calls `loadUrl`, normalizing across the hidden iframe.
Chris@0:     checkUrl: function(e) {
Chris@0:       var current = this.getFragment();
Chris@0: 
Chris@0:       // If the user pressed the back button, the iframe's hash will have
Chris@0:       // changed and we should use that for comparison.
Chris@0:       if (current === this.fragment && this.iframe) {
Chris@0:         current = this.getHash(this.iframe.contentWindow);
Chris@0:       }
Chris@0: 
Chris@0:       if (current === this.fragment) return false;
Chris@0:       if (this.iframe) this.navigate(current);
Chris@0:       this.loadUrl();
Chris@0:     },
Chris@0: 
Chris@0:     // Attempt to load the current URL fragment. If a route succeeds with a
Chris@0:     // match, returns `true`. If no defined routes matches the fragment,
Chris@0:     // returns `false`.
Chris@0:     loadUrl: function(fragment) {
Chris@0:       // If the root doesn't match, no routes can match either.
Chris@0:       if (!this.matchRoot()) return false;
Chris@0:       fragment = this.fragment = this.getFragment(fragment);
Chris@0:       return _.some(this.handlers, function(handler) {
Chris@0:         if (handler.route.test(fragment)) {
Chris@0:           handler.callback(fragment);
Chris@0:           return true;
Chris@0:         }
Chris@0:       });
Chris@0:     },
Chris@0: 
Chris@0:     // Save a fragment into the hash history, or replace the URL state if the
Chris@0:     // 'replace' option is passed. You are responsible for properly URL-encoding
Chris@0:     // the fragment in advance.
Chris@0:     //
Chris@0:     // The options object can contain `trigger: true` if you wish to have the
Chris@0:     // route callback be fired (not usually desirable), or `replace: true`, if
Chris@0:     // you wish to modify the current URL without adding an entry to the history.
Chris@0:     navigate: function(fragment, options) {
Chris@0:       if (!History.started) return false;
Chris@0:       if (!options || options === true) options = {trigger: !!options};
Chris@0: 
Chris@0:       // Normalize the fragment.
Chris@0:       fragment = this.getFragment(fragment || '');
Chris@0: 
Chris@0:       // Don't include a trailing slash on the root.
Chris@0:       var root = this.root;
Chris@0:       if (fragment === '' || fragment.charAt(0) === '?') {
Chris@0:         root = root.slice(0, -1) || '/';
Chris@0:       }
Chris@0:       var url = root + fragment;
Chris@0: 
Chris@0:       // Strip the hash and decode for matching.
Chris@0:       fragment = this.decodeFragment(fragment.replace(pathStripper, ''));
Chris@0: 
Chris@0:       if (this.fragment === fragment) return;
Chris@0:       this.fragment = fragment;
Chris@0: 
Chris@0:       // If pushState is available, we use it to set the fragment as a real URL.
Chris@0:       if (this._usePushState) {
Chris@0:         this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);
Chris@0: 
Chris@0:       // If hash changes haven't been explicitly disabled, update the hash
Chris@0:       // fragment to store history.
Chris@0:       } else if (this._wantsHashChange) {
Chris@0:         this._updateHash(this.location, fragment, options.replace);
Chris@0:         if (this.iframe && (fragment !== this.getHash(this.iframe.contentWindow))) {
Chris@0:           var iWindow = this.iframe.contentWindow;
Chris@0: 
Chris@0:           // Opening and closing the iframe tricks IE7 and earlier to push a
Chris@0:           // history entry on hash-tag change.  When replace is true, we don't
Chris@0:           // want this.
Chris@0:           if (!options.replace) {
Chris@0:             iWindow.document.open();
Chris@0:             iWindow.document.close();
Chris@0:           }
Chris@0: 
Chris@0:           this._updateHash(iWindow.location, fragment, options.replace);
Chris@0:         }
Chris@0: 
Chris@0:       // If you've told us that you explicitly don't want fallback hashchange-
Chris@0:       // based history, then `navigate` becomes a page refresh.
Chris@0:       } else {
Chris@0:         return this.location.assign(url);
Chris@0:       }
Chris@0:       if (options.trigger) return this.loadUrl(fragment);
Chris@0:     },
Chris@0: 
Chris@0:     // Update the hash location, either replacing the current entry, or adding
Chris@0:     // a new one to the browser history.
Chris@0:     _updateHash: function(location, fragment, replace) {
Chris@0:       if (replace) {
Chris@0:         var href = location.href.replace(/(javascript:|#).*$/, '');
Chris@0:         location.replace(href + '#' + fragment);
Chris@0:       } else {
Chris@0:         // Some browsers require that `hash` contains a leading #.
Chris@0:         location.hash = '#' + fragment;
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:   });
Chris@0: 
Chris@0:   // Create the default Backbone.history.
Chris@0:   Backbone.history = new History;
Chris@0: 
Chris@0:   // Helpers
Chris@0:   // -------
Chris@0: 
Chris@0:   // Helper function to correctly set up the prototype chain for subclasses.
Chris@0:   // Similar to `goog.inherits`, but uses a hash of prototype properties and
Chris@0:   // class properties to be extended.
Chris@0:   var extend = function(protoProps, staticProps) {
Chris@0:     var parent = this;
Chris@0:     var child;
Chris@0: 
Chris@0:     // The constructor function for the new subclass is either defined by you
Chris@0:     // (the "constructor" property in your `extend` definition), or defaulted
Chris@0:     // by us to simply call the parent constructor.
Chris@0:     if (protoProps && _.has(protoProps, 'constructor')) {
Chris@0:       child = protoProps.constructor;
Chris@0:     } else {
Chris@0:       child = function(){ return parent.apply(this, arguments); };
Chris@0:     }
Chris@0: 
Chris@0:     // Add static properties to the constructor function, if supplied.
Chris@0:     _.extend(child, parent, staticProps);
Chris@0: 
Chris@0:     // Set the prototype chain to inherit from `parent`, without calling
Chris@0:     // `parent` constructor function.
Chris@0:     var Surrogate = function(){ this.constructor = child; };
Chris@0:     Surrogate.prototype = parent.prototype;
Chris@0:     child.prototype = new Surrogate;
Chris@0: 
Chris@0:     // Add prototype properties (instance properties) to the subclass,
Chris@0:     // if supplied.
Chris@0:     if (protoProps) _.extend(child.prototype, protoProps);
Chris@0: 
Chris@0:     // Set a convenience property in case the parent's prototype is needed
Chris@0:     // later.
Chris@0:     child.__super__ = parent.prototype;
Chris@0: 
Chris@0:     return child;
Chris@0:   };
Chris@0: 
Chris@0:   // Set up inheritance for the model, collection, router, view and history.
Chris@0:   Model.extend = Collection.extend = Router.extend = View.extend = History.extend = extend;
Chris@0: 
Chris@0:   // Throw an error when a URL is needed, and none is supplied.
Chris@0:   var urlError = function() {
Chris@0:     throw new Error('A "url" property or function must be specified');
Chris@0:   };
Chris@0: 
Chris@0:   // Wrap an optional error callback with a fallback error event.
Chris@0:   var wrapError = function(model, options) {
Chris@0:     var error = options.error;
Chris@0:     options.error = function(resp) {
Chris@0:       if (error) error.call(options.context, model, resp, options);
Chris@0:       model.trigger('error', model, resp, options);
Chris@0:     };
Chris@0:   };
Chris@0: 
Chris@0:   return Backbone;
Chris@0: 
Chris@0: }));