diff -r f507feede89a -r 09a1c134465b web/wp-includes/js/media-models.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/wp-includes/js/media-models.js	Wed Dec 19 17:46:52 2012 -0800
@@ -0,0 +1,908 @@
+window.wp = window.wp || {};
+
+(function($){
+	var Attachment, Attachments, Query, compare, l10n, media;
+
+	/**
+	 * wp.media( attributes )
+	 *
+	 * Handles the default media experience. Automatically creates
+	 * and opens a media frame, and returns the result.
+	 * Does nothing if the controllers do not exist.
+	 *
+	 * @param  {object} attributes The properties passed to the main media controller.
+	 * @return {object}            A media workflow.
+	 */
+	media = wp.media = function( attributes ) {
+		var MediaFrame = media.view.MediaFrame,
+			frame;
+
+		if ( ! MediaFrame )
+			return;
+
+		attributes = _.defaults( attributes || {}, {
+			frame: 'select'
+		});
+
+		if ( 'select' === attributes.frame && MediaFrame.Select )
+			frame = new MediaFrame.Select( attributes );
+		else if ( 'post' === attributes.frame && MediaFrame.Post )
+			frame = new MediaFrame.Post( attributes );
+
+		delete attributes.frame;
+
+		return frame;
+	};
+
+	_.extend( media, { model: {}, view: {}, controller: {}, frames: {} });
+
+	// Link any localized strings.
+	l10n = media.model.l10n = typeof _wpMediaModelsL10n === 'undefined' ? {} : _wpMediaModelsL10n;
+
+	// Link any settings.
+	media.model.settings = l10n.settings || {};
+	delete l10n.settings;
+
+	/**
+	 * ========================================================================
+	 * UTILITIES
+	 * ========================================================================
+	 */
+
+	/**
+	 * A basic comparator.
+	 *
+	 * @param  {mixed}  a  The primary parameter to compare.
+	 * @param  {mixed}  b  The primary parameter to compare.
+	 * @param  {string} ac The fallback parameter to compare, a's cid.
+	 * @param  {string} bc The fallback parameter to compare, b's cid.
+	 * @return {number}    -1: a should come before b.
+	 *                      0: a and b are of the same rank.
+	 *                      1: b should come before a.
+	 */
+	compare = function( a, b, ac, bc ) {
+		if ( _.isEqual( a, b ) )
+			return ac === bc ? 0 : (ac > bc ? -1 : 1);
+		else
+			return a > b ? -1 : 1;
+	};
+
+	_.extend( media, {
+		/**
+		 * media.template( id )
+		 *
+		 * Fetches a template by id.
+		 *
+		 * @param  {string} id   A string that corresponds to a DOM element with an id prefixed with "tmpl-".
+		 *                       For example, "attachment" maps to "tmpl-attachment".
+		 * @return {function}    A function that lazily-compiles the template requested.
+		 */
+		template: _.memoize( function( id ) {
+			var compiled,
+				options = {
+					evaluate:    /<#([\s\S]+?)#>/g,
+					interpolate: /\{\{\{([\s\S]+?)\}\}\}/g,
+					escape:      /\{\{([^\}]+?)\}\}(?!\})/g,
+					variable:    'data'
+				};
+
+			return function( data ) {
+				compiled = compiled || _.template( $( '#tmpl-' + id ).html(), null, options );
+				return compiled( data );
+			};
+		}),
+
+		/**
+		 * media.post( [action], [data] )
+		 *
+		 * Sends a POST request to WordPress.
+		 *
+		 * @param  {string} action The slug of the action to fire in WordPress.
+		 * @param  {object} data   The data to populate $_POST with.
+		 * @return {$.promise}     A jQuery promise that represents the request.
+		 */
+		post: function( action, data ) {
+			return media.ajax({
+				data: _.isObject( action ) ? action : _.extend( data || {}, { action: action })
+			});
+		},
+
+		/**
+		 * media.ajax( [action], [options] )
+		 *
+		 * Sends a POST request to WordPress.
+		 *
+		 * @param  {string} action  The slug of the action to fire in WordPress.
+		 * @param  {object} options The options passed to jQuery.ajax.
+		 * @return {$.promise}      A jQuery promise that represents the request.
+		 */
+		ajax: function( action, options ) {
+			if ( _.isObject( action ) ) {
+				options = action;
+			} else {
+				options = options || {};
+				options.data = _.extend( options.data || {}, { action: action });
+			}
+
+			options = _.defaults( options || {}, {
+				type:    'POST',
+				url:     media.model.settings.ajaxurl,
+				context: this
+			});
+
+			return $.Deferred( function( deferred ) {
+				// Transfer success/error callbacks.
+				if ( options.success )
+					deferred.done( options.success );
+				if ( options.error )
+					deferred.fail( options.error );
+
+				delete options.success;
+				delete options.error;
+
+				// Use with PHP's wp_send_json_success() and wp_send_json_error()
+				$.ajax( options ).done( function( response ) {
+					// Treat a response of `1` as successful for backwards
+					// compatibility with existing handlers.
+					if ( response === '1' || response === 1 )
+						response = { success: true };
+
+					if ( _.isObject( response ) && ! _.isUndefined( response.success ) )
+						deferred[ response.success ? 'resolveWith' : 'rejectWith' ]( this, [response.data] );
+					else
+						deferred.rejectWith( this, [response] );
+				}).fail( function() {
+					deferred.rejectWith( this, arguments );
+				});
+			}).promise();
+		},
+
+		// Scales a set of dimensions to fit within bounding dimensions.
+		fit: function( dimensions ) {
+			var width     = dimensions.width,
+				height    = dimensions.height,
+				maxWidth  = dimensions.maxWidth,
+				maxHeight = dimensions.maxHeight,
+				constraint;
+
+			// Compare ratios between the two values to determine which
+			// max to constrain by. If a max value doesn't exist, then the
+			// opposite side is the constraint.
+			if ( ! _.isUndefined( maxWidth ) && ! _.isUndefined( maxHeight ) ) {
+				constraint = ( width / height > maxWidth / maxHeight ) ? 'width' : 'height';
+			} else if ( _.isUndefined( maxHeight ) ) {
+				constraint = 'width';
+			} else if (  _.isUndefined( maxWidth ) && height > maxHeight ) {
+				constraint = 'height';
+			}
+
+			// If the value of the constrained side is larger than the max,
+			// then scale the values. Otherwise return the originals; they fit.
+			if ( 'width' === constraint && width > maxWidth ) {
+				return {
+					width : maxWidth,
+					height: Math.round( maxWidth * height / width )
+				};
+			} else if ( 'height' === constraint && height > maxHeight ) {
+				return {
+					width : Math.round( maxHeight * width / height ),
+					height: maxHeight
+				};
+			} else {
+				return {
+					width : width,
+					height: height
+				};
+			}
+		},
+
+		// Truncates a string by injecting an ellipsis into the middle.
+		// Useful for filenames.
+		truncate: function( string, length, replacement ) {
+			length = length || 30;
+			replacement = replacement || '&hellip;';
+
+			if ( string.length <= length )
+				return string;
+
+			return string.substr( 0, length / 2 ) + replacement + string.substr( -1 * length / 2 );
+		}
+	});
+
+
+	/**
+	 * ========================================================================
+	 * MODELS
+	 * ========================================================================
+	 */
+
+	 /**
+	  * wp.media.attachment
+	  */
+	 media.attachment = function( id ) {
+		return Attachment.get( id );
+	 };
+
+	/**
+	 * wp.media.model.Attachment
+	 */
+	Attachment = media.model.Attachment = Backbone.Model.extend({
+		sync: function( method, model, options ) {
+			// If the attachment does not yet have an `id`, return an instantly
+			// rejected promise. Otherwise, all of our requests will fail.
+			if ( _.isUndefined( this.id ) )
+				return $.Deferred().rejectWith( this ).promise();
+
+			// Overload the `read` request so Attachment.fetch() functions correctly.
+			if ( 'read' === method ) {
+				options = options || {};
+				options.context = this;
+				options.data = _.extend( options.data || {}, {
+					action: 'get-attachment',
+					id: this.id
+				});
+				return media.ajax( options );
+
+			// Overload the `update` request so properties can be saved.
+			} else if ( 'update' === method ) {
+				// If we do not have the necessary nonce, fail immeditately.
+				if ( ! this.get('nonces') || ! this.get('nonces').update )
+					return $.Deferred().rejectWith( this ).promise();
+
+				options = options || {};
+				options.context = this;
+
+				// Set the action and ID.
+				options.data = _.extend( options.data || {}, {
+					action:  'save-attachment',
+					id:      this.id,
+					nonce:   this.get('nonces').update,
+					post_id: media.model.settings.post.id
+				});
+
+				// Record the values of the changed attributes.
+				if ( options.changes ) {
+					_.each( options.changes, function( value, key ) {
+						options.changes[ key ] = this.get( key );
+					}, this );
+
+					options.data.changes = options.changes;
+					delete options.changes;
+				}
+
+				return media.ajax( options );
+
+			// Overload the `delete` request so attachments can be removed.
+			// This will permanently delete an attachment.
+			} else if ( 'delete' === method ) {
+				options = options || {};
+
+				if ( ! options.wait )
+					this.destroyed = true;
+
+				options.context = this;
+				options.data = _.extend( options.data || {}, {
+					action:   'delete-post',
+					id:       this.id,
+					_wpnonce: this.get('nonces')['delete']
+				});
+
+				return media.ajax( options ).done( function() {
+					this.destroyed = true;
+				}).fail( function() {
+					this.destroyed = false;
+				});
+			}
+		},
+
+		parse: function( resp, xhr ) {
+			if ( ! resp )
+				return resp;
+
+			// Convert date strings into Date objects.
+			resp.date = new Date( resp.date );
+			resp.modified = new Date( resp.modified );
+			return resp;
+		},
+
+		saveCompat: function( data, options ) {
+			var model = this;
+
+			// If we do not have the necessary nonce, fail immeditately.
+			if ( ! this.get('nonces') || ! this.get('nonces').update )
+				return $.Deferred().rejectWith( this ).promise();
+
+			return media.post( 'save-attachment-compat', _.defaults({
+				id:      this.id,
+				nonce:   this.get('nonces').update,
+				post_id: media.model.settings.post.id
+			}, data ) ).done( function( resp, status, xhr ) {
+				model.set( model.parse( resp, xhr ), options );
+			});
+		}
+	}, {
+		create: function( attrs ) {
+			return Attachments.all.push( attrs );
+		},
+
+		get: _.memoize( function( id, attachment ) {
+			return Attachments.all.push( attachment || { id: id } );
+		})
+	});
+
+	/**
+	 * wp.media.model.Attachments
+	 */
+	Attachments = media.model.Attachments = Backbone.Collection.extend({
+		model: Attachment,
+
+		initialize: function( models, options ) {
+			options = options || {};
+
+			this.props   = new Backbone.Model();
+			this.filters = options.filters || {};
+
+			// Bind default `change` events to the `props` model.
+			this.props.on( 'change', this._changeFilteredProps, this );
+
+			this.props.on( 'change:order',   this._changeOrder,   this );
+			this.props.on( 'change:orderby', this._changeOrderby, this );
+			this.props.on( 'change:query',   this._changeQuery,   this );
+
+			// Set the `props` model and fill the default property values.
+			this.props.set( _.defaults( options.props || {} ) );
+
+			// Observe another `Attachments` collection if one is provided.
+			if ( options.observe )
+				this.observe( options.observe );
+		},
+
+		// Automatically sort the collection when the order changes.
+		_changeOrder: function( model, order ) {
+			if ( this.comparator )
+				this.sort();
+		},
+
+		// Set the default comparator only when the `orderby` property is set.
+		_changeOrderby: function( model, orderby ) {
+			// If a different comparator is defined, bail.
+			if ( this.comparator && this.comparator !== Attachments.comparator )
+				return;
+
+			if ( orderby && 'post__in' !== orderby )
+				this.comparator = Attachments.comparator;
+			else
+				delete this.comparator;
+		},
+
+		// If the `query` property is set to true, query the server using
+		// the `props` values, and sync the results to this collection.
+		_changeQuery: function( model, query ) {
+			if ( query ) {
+				this.props.on( 'change', this._requery, this );
+				this._requery();
+			} else {
+				this.props.off( 'change', this._requery, this );
+			}
+		},
+
+		_changeFilteredProps: function( model, options ) {
+			// If this is a query, updating the collection will be handled by
+			// `this._requery()`.
+			if ( this.props.get('query') )
+				return;
+
+			var changed = _.chain( options.changes ).map( function( t, prop ) {
+				var filter = Attachments.filters[ prop ],
+					term = model.get( prop );
+
+				if ( ! filter )
+					return;
+
+				if ( term && ! this.filters[ prop ] )
+					this.filters[ prop ] = filter;
+				else if ( ! term && this.filters[ prop ] === filter )
+					delete this.filters[ prop ];
+				else
+					return;
+
+				// Record the change.
+				return true;
+			}, this ).any().value();
+
+			if ( ! changed )
+				return;
+
+			// If no `Attachments` model is provided to source the searches
+			// from, then automatically generate a source from the existing
+			// models.
+			if ( ! this._source )
+				this._source = new Attachments( this.models );
+
+			this.reset( this._source.filter( this.validator, this ) );
+		},
+
+		validateDestroyed: false,
+
+		validator: function( attachment ) {
+			if ( ! this.validateDestroyed && attachment.destroyed )
+				return false;
+			return _.all( this.filters, function( filter, key ) {
+				return !! filter.call( this, attachment );
+			}, this );
+		},
+
+		validate: function( attachment, options ) {
+			var valid = this.validator( attachment ),
+				hasAttachment = !! this.getByCid( attachment.cid );
+
+			if ( ! valid && hasAttachment )
+				this.remove( attachment, options );
+			else if ( valid && ! hasAttachment )
+				this.add( attachment, options );
+
+			return this;
+		},
+
+		validateAll: function( attachments, options ) {
+			options = options || {};
+
+			_.each( attachments.models, function( attachment ) {
+				this.validate( attachment, { silent: true });
+			}, this );
+
+			if ( ! options.silent )
+				this.trigger( 'reset', this, options );
+
+			return this;
+		},
+
+		observe: function( attachments ) {
+			this.observers = this.observers || [];
+			this.observers.push( attachments );
+
+			attachments.on( 'add change remove', this._validateHandler, this );
+			attachments.on( 'reset', this._validateAllHandler, this );
+
+			this.validateAll( attachments );
+			return this;
+		},
+
+		unobserve: function( attachments ) {
+			if ( attachments ) {
+				attachments.off( null, null, this );
+				this.observers = _.without( this.observers, attachments );
+
+			} else {
+				_.each( this.observers, function( attachments ) {
+					attachments.off( null, null, this );
+				}, this );
+				delete this.observers;
+			}
+
+			return this;
+		},
+
+		_validateHandler: function( attachment, attachments, options ) {
+			// If we're not mirroring this `attachments` collection,
+			// only retain the `silent` option.
+			options = attachments === this.mirroring ? options : {
+				silent: options && options.silent
+			};
+
+			return this.validate( attachment, options );
+		},
+
+		_validateAllHandler: function( attachments, options ) {
+			return this.validateAll( attachments, options );
+		},
+
+		mirror: function( attachments ) {
+			if ( this.mirroring && this.mirroring === attachments )
+				return this;
+
+			this.unmirror();
+			this.mirroring = attachments;
+
+			// Clear the collection silently. A `reset` event will be fired
+			// when `observe()` calls `validateAll()`.
+			this.reset( [], { silent: true } );
+			this.observe( attachments );
+
+			return this;
+		},
+
+		unmirror: function() {
+			if ( ! this.mirroring )
+				return;
+
+			this.unobserve( this.mirroring );
+			delete this.mirroring;
+		},
+
+		more: function( options ) {
+			var deferred = $.Deferred(),
+				mirroring = this.mirroring,
+				attachments = this;
+
+			if ( ! mirroring || ! mirroring.more )
+				return deferred.resolveWith( this ).promise();
+
+			// If we're mirroring another collection, forward `more` to
+			// the mirrored collection. Account for a race condition by
+			// checking if we're still mirroring that collection when
+			// the request resolves.
+			mirroring.more( options ).done( function() {
+				if ( this === attachments.mirroring )
+					deferred.resolveWith( this );
+			});
+
+			return deferred.promise();
+		},
+
+		hasMore: function() {
+			return this.mirroring ? this.mirroring.hasMore() : false;
+		},
+
+		parse: function( resp, xhr ) {
+			return _.map( resp, function( attrs ) {
+				var attachment = Attachment.get( attrs.id );
+				return attachment.set( attachment.parse( attrs, xhr ) );
+			});
+		},
+
+		_requery: function() {
+			if ( this.props.get('query') )
+				this.mirror( Query.get( this.props.toJSON() ) );
+		},
+
+		// If this collection is sorted by `menuOrder`, recalculates and saves
+		// the menu order to the database.
+		saveMenuOrder: function() {
+			if ( 'menuOrder' !== this.props.get('orderby') )
+				return;
+
+			// Removes any uploading attachments, updates each attachment's
+			// menu order, and returns an object with an { id: menuOrder }
+			// mapping to pass to the request.
+			var attachments = this.chain().filter( function( attachment ) {
+				return ! _.isUndefined( attachment.id );
+			}).map( function( attachment, index ) {
+				// Indices start at 1.
+				index = index + 1;
+				attachment.set( 'menuOrder', index );
+				return [ attachment.id, index ];
+			}).object().value();
+
+			if ( _.isEmpty( attachments ) )
+				return;
+
+			return media.post( 'save-attachment-order', {
+				nonce:       media.model.settings.post.nonce,
+				post_id:     media.model.settings.post.id,
+				attachments: attachments
+			});
+		}
+	}, {
+		comparator: function( a, b, options ) {
+			var key   = this.props.get('orderby'),
+				order = this.props.get('order') || 'DESC',
+				ac    = a.cid,
+				bc    = b.cid;
+
+			a = a.get( key );
+			b = b.get( key );
+
+			if ( 'date' === key || 'modified' === key ) {
+				a = a || new Date();
+				b = b || new Date();
+			}
+
+			// If `options.ties` is set, don't enforce the `cid` tiebreaker.
+			if ( options && options.ties )
+				ac = bc = null;
+
+			return ( 'DESC' === order ) ? compare( a, b, ac, bc ) : compare( b, a, bc, ac );
+		},
+
+		filters: {
+			// Note that this client-side searching is *not* equivalent
+			// to our server-side searching.
+			search: function( attachment ) {
+				if ( ! this.props.get('search') )
+					return true;
+
+				return _.any(['title','filename','description','caption','name'], function( key ) {
+					var value = attachment.get( key );
+					return value && -1 !== value.search( this.props.get('search') );
+				}, this );
+			},
+
+			type: function( attachment ) {
+				var type = this.props.get('type');
+				return ! type || -1 !== type.indexOf( attachment.get('type') );
+			},
+
+			uploadedTo: function( attachment ) {
+				var uploadedTo = this.props.get('uploadedTo');
+				if ( _.isUndefined( uploadedTo ) )
+					return true;
+
+				return uploadedTo === attachment.get('uploadedTo');
+			}
+		}
+	});
+
+	Attachments.all = new Attachments();
+
+	/**
+	 * wp.media.query
+	 */
+	media.query = function( props ) {
+		return new Attachments( null, {
+			props: _.extend( _.defaults( props || {}, { orderby: 'date' } ), { query: true } )
+		});
+	};
+
+	/**
+	 * wp.media.model.Query
+	 *
+	 * A set of attachments that corresponds to a set of consecutively paged
+	 * queries on the server.
+	 *
+	 * Note: Do NOT change this.args after the query has been initialized.
+	 *       Things will break.
+	 */
+	Query = media.model.Query = Attachments.extend({
+		initialize: function( models, options ) {
+			var allowed;
+
+			options = options || {};
+			Attachments.prototype.initialize.apply( this, arguments );
+
+			this.args     = options.args;
+			this._hasMore = true;
+			this.created  = new Date();
+
+			this.filters.order = function( attachment ) {
+				var orderby = this.props.get('orderby'),
+					order = this.props.get('order');
+
+				if ( ! this.comparator )
+					return true;
+
+				// We want any items that can be placed before the last
+				// item in the set. If we add any items after the last
+				// item, then we can't guarantee the set is complete.
+				if ( this.length ) {
+					return 1 !== this.comparator( attachment, this.last(), { ties: true });
+
+				// Handle the case where there are no items yet and
+				// we're sorting for recent items. In that case, we want
+				// changes that occurred after we created the query.
+				} else if ( 'DESC' === order && ( 'date' === orderby || 'modified' === orderby ) ) {
+					return attachment.get( orderby ) >= this.created;
+
+				// If we're sorting by menu order and we have no items,
+				// accept any items that have the default menu order (0).
+				} else if ( 'ASC' === order && 'menuOrder' === orderby ) {
+					return attachment.get( orderby ) === 0;
+				}
+
+				// Otherwise, we don't want any items yet.
+				return false;
+			};
+
+			// Observe the central `wp.Uploader.queue` collection to watch for
+			// new matches for the query.
+			//
+			// Only observe when a limited number of query args are set. There
+			// are no filters for other properties, so observing will result in
+			// false positives in those queries.
+			allowed = [ 's', 'order', 'orderby', 'posts_per_page', 'post_mime_type', 'post_parent' ];
+			if ( wp.Uploader && _( this.args ).chain().keys().difference( allowed ).isEmpty().value() )
+				this.observe( wp.Uploader.queue );
+		},
+
+		hasMore: function() {
+			return this._hasMore;
+		},
+
+		more: function( options ) {
+			var query = this;
+
+			if ( this._more && 'pending' === this._more.state() )
+				return this._more;
+
+			if ( ! this.hasMore() )
+				return $.Deferred().resolveWith( this ).promise();
+
+			options = options || {};
+			options.add = true;
+
+			return this._more = this.fetch( options ).done( function( resp ) {
+				if ( _.isEmpty( resp ) || -1 === this.args.posts_per_page || resp.length < this.args.posts_per_page )
+					query._hasMore = false;
+			});
+		},
+
+		sync: function( method, model, options ) {
+			var fallback;
+
+			// Overload the read method so Attachment.fetch() functions correctly.
+			if ( 'read' === method ) {
+				options = options || {};
+				options.context = this;
+				options.data = _.extend( options.data || {}, {
+					action:  'query-attachments',
+					post_id: media.model.settings.post.id
+				});
+
+				// Clone the args so manipulation is non-destructive.
+				args = _.clone( this.args );
+
+				// Determine which page to query.
+				if ( -1 !== args.posts_per_page )
+					args.paged = Math.floor( this.length / args.posts_per_page ) + 1;
+
+				options.data.query = args;
+				return media.ajax( options );
+
+			// Otherwise, fall back to Backbone.sync()
+			} else {
+				fallback = Attachments.prototype.sync ? Attachments.prototype : Backbone;
+				return fallback.sync.apply( this, arguments );
+			}
+		}
+	}, {
+		defaultProps: {
+			orderby: 'date',
+			order:   'DESC'
+		},
+
+		defaultArgs: {
+			posts_per_page: 40
+		},
+
+		orderby: {
+			allowed:  [ 'name', 'author', 'date', 'title', 'modified', 'uploadedTo', 'id', 'post__in', 'menuOrder' ],
+			valuemap: {
+				'id':         'ID',
+				'uploadedTo': 'parent',
+				'menuOrder':  'menu_order ID'
+			}
+		},
+
+		propmap: {
+			'search':    's',
+			'type':      'post_mime_type',
+			'perPage':   'posts_per_page',
+			'menuOrder': 'menu_order',
+			'uploadedTo': 'post_parent'
+		},
+
+		// Caches query objects so queries can be easily reused.
+		get: (function(){
+			var queries = [];
+
+			return function( props, options ) {
+				var args     = {},
+					orderby  = Query.orderby,
+					defaults = Query.defaultProps,
+					query;
+
+				// Remove the `query` property. This isn't linked to a query,
+				// this *is* the query.
+				delete props.query;
+
+				// Fill default args.
+				_.defaults( props, defaults );
+
+				// Normalize the order.
+				props.order = props.order.toUpperCase();
+				if ( 'DESC' !== props.order && 'ASC' !== props.order )
+					props.order = defaults.order.toUpperCase();
+
+				// Ensure we have a valid orderby value.
+				if ( ! _.contains( orderby.allowed, props.orderby ) )
+					props.orderby = defaults.orderby;
+
+				// Generate the query `args` object.
+				// Correct any differing property names.
+				_.each( props, function( value, prop ) {
+					if ( _.isNull( value ) )
+						return;
+
+					args[ Query.propmap[ prop ] || prop ] = value;
+				});
+
+				// Fill any other default query args.
+				_.defaults( args, Query.defaultArgs );
+
+				// `props.orderby` does not always map directly to `args.orderby`.
+				// Substitute exceptions specified in orderby.keymap.
+				args.orderby = orderby.valuemap[ props.orderby ] || props.orderby;
+
+				// Search the query cache for matches.
+				query = _.find( queries, function( query ) {
+					return _.isEqual( query.args, args );
+				});
+
+				// Otherwise, create a new query and add it to the cache.
+				if ( ! query ) {
+					query = new Query( [], _.extend( options || {}, {
+						props: props,
+						args:  args
+					} ) );
+					queries.push( query );
+				}
+
+				return query;
+			};
+		}())
+	});
+
+	/**
+	 * wp.media.model.Selection
+	 *
+	 * Used to manage a selection of attachments in the views.
+	 */
+	media.model.Selection = Attachments.extend({
+		initialize: function( models, options ) {
+			Attachments.prototype.initialize.apply( this, arguments );
+			this.multiple = options && options.multiple;
+
+			// Refresh the `single` model whenever the selection changes.
+			// Binds `single` instead of using the context argument to ensure
+			// it receives no parameters.
+			this.on( 'add remove reset', _.bind( this.single, this, false ) );
+		},
+
+		// Override the selection's add method.
+		// If the workflow does not support multiple
+		// selected attachments, reset the selection.
+		add: function( models, options ) {
+			if ( ! this.multiple )
+				this.remove( this.models );
+
+			return Attachments.prototype.add.call( this, models, options );
+		},
+
+		single: function( model ) {
+			var previous = this._single;
+
+			// If a `model` is provided, use it as the single model.
+			if ( model )
+				this._single = model;
+
+			// If the single model isn't in the selection, remove it.
+			if ( this._single && ! this.getByCid( this._single.cid ) )
+				delete this._single;
+
+			this._single = this._single || this.last();
+
+			// If single has changed, fire an event.
+			if ( this._single !== previous ) {
+				if ( previous ) {
+					previous.trigger( 'selection:unsingle', previous, this );
+
+					// If the model was already removed, trigger the collection
+					// event manually.
+					if ( ! this.getByCid( previous.cid ) )
+						this.trigger( 'selection:unsingle', previous, this );
+				}
+				if ( this._single )
+					this._single.trigger( 'selection:single', this._single, this );
+			}
+
+			// Return the single model, or the last model as a fallback.
+			return this._single;
+		}
+	});
+
+	// Clean up. Prevents mobile browsers caching
+	$(window).on('unload', function(){
+		window.wp = null;
+	});
+
+}(jQuery));
\ No newline at end of file