Added some small comments to widget code

IPython/html/static/notebook/js/widgetmanager.js

@@ -1,186 +1,188 b''
 //----------------------------------------------------------------------------
 //  Copyright (C) 2013  The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // WidgetModel, WidgetView, and WidgetManager
 //============================================================================
 /**
  * Base Widget classes
  * @module IPython
  * @namespace IPython
  * @submodule widget
  */
 
 (function () {
     "use strict";
 
     // Use require.js 'define' method so that require.js is intelligent enough to
     // syncronously load everything within this file when it is being 'required' 
     // elsewhere.
     define(["underscore",
              "backbone",
             ], function (Underscore, Backbone) {
 
         //--------------------------------------------------------------------
         // WidgetManager class
         //--------------------------------------------------------------------
         var WidgetManager = function (comm_manager) {
             // Public constructor
             WidgetManager._managers.push(this);
 
             // Attach a comm manager to the 
             this.comm_manager = comm_manager;
             this._models = {}; /* Dictionary of model ids and model instances */
 
             // Register already-registered widget model types with the comm manager.
             _.each(WidgetManager._model_types, function(value, key) {
                 this.comm_manager.register_target(value, $.proxy(this._handle_comm_open, this));
             });
         };
 
         //--------------------------------------------------------------------
         // Class level
         //--------------------------------------------------------------------
         WidgetManager._model_types = {}; /* Dictionary of model type names (target_name) and model types. */
         WidgetManager._view_types = {}; /* Dictionary of view names and view types. */
         WidgetManager._managers = []; /* List of widget managers */
 
         WidgetManager.register_widget_model = function (model_name, model_type) {
             // Registers a widget model by name.
             WidgetManager._model_types[model_name] = model_type;
 
             // Register the widget with the comm manager.  Make sure to pass this object's context
             // in so `this` works in the call back.
             _.each(WidgetManager._managers, function(instance, i) {
                 if (instance.comm_manager !== null) {
                     instance.comm_manager.register_target(model_name, $.proxy(instance._handle_comm_open, instance));
                 }
             });
         };
 
         WidgetManager.register_widget_view = function (view_name, view_type) {
             // Registers a widget view by name.
             WidgetManager._view_types[view_name] = view_type;
         };
 
         //--------------------------------------------------------------------
         // Instance level
         //--------------------------------------------------------------------
         WidgetManager.prototype.display_view = function(msg, model) {
             var cell = this.get_msg_cell(msg.parent_header.msg_id);
             if (cell === null) {
                 console.log("Could not determine where the display" + 
                     " message was from.  Widget will not be displayed");
             } else {
                 var view = this.create_view(model, {cell: cell});
                 if (view === null) {
                     console.error("View creation failed", model);
                 }
                 if (cell.widget_subarea !== undefined
                     && cell.widget_subarea !== null) {
                     
                     cell.widget_area.show();
                     cell.widget_subarea.append(view.$el);
                 }
             }
         },
 
         WidgetManager.prototype.create_view = function(model, options) {
             var view_name = model.get('view_name');
             var ViewType = WidgetManager._view_types[view_name];
             if (ViewType !== undefined && ViewType !== null) {
                 var parameters = {model: model, options: options};
                 var view = new ViewType(parameters);
                 view.render();
                 IPython.keyboard_manager.register_events(view.$el);
                 model.views.push(view);
                 model.on('destroy', view.remove, view);
                 return view;
             }
             return null;
         },
 
         WidgetManager.prototype.get_msg_cell = function (msg_id) {
             var cell = null;
             // First, check to see if the msg was triggered by cell execution.
             if (IPython.notebook !== undefined && IPython.notebook !== null) {
                 cell = IPython.notebook.get_msg_cell(msg_id);
             }
             if (cell !== null) {
                 return cell
             }
             // Second, check to see if a get_cell callback was defined
             // for the message.  get_cell callbacks are registered for
             // widget messages, so this block is actually checking to see if the
             // message was triggered by a widget.
             var kernel = this.comm_manager.kernel;
             if (kernel !== undefined && kernel !== null) {
                 var callbacks = kernel.get_callbacks_for_msg(msg_id);
                 if (callbacks !== undefined && 
                     callbacks.iopub !== undefined && 
                     callbacks.iopub.get_cell !== undefined) {
 
                     return callbacks.iopub.get_cell();
                 }    
             }
             
             // Not triggered by a cell or widget (no get_cell callback 
             // exists).
             return null;
         };
 
         WidgetManager.prototype.callbacks = function (view) {
             // callback handlers specific a view
             var callbacks = {};
             var cell = view.options.cell;
             if (cell !== null) {
                 // Try to get output handlers
                 var handle_output = null;
                 var handle_clear_output = null;
                 if (cell.output_area !== undefined && cell.output_area !== null) {
                     handle_output = $.proxy(cell.output_area.handle_output, cell.output_area);
                     handle_clear_output = $.proxy(cell.output_area.handle_clear_output, cell.output_area);
                 }
 
                 // Create callback dict using what is known
                 var that = this;
                 callbacks = {
                     iopub : {
                         output : handle_output,
                         clear_output : handle_clear_output,
 
                         // Special function only registered by widget messages.
                         // Allows us to get the cell for a message so we know
                         // where to add widgets if the code requires it.
                         get_cell : function () {
                             return cell;
                         },
                     },
                 };
             }
             return callbacks;
         };
 
         WidgetManager.prototype.get_model = function (model_id) {
+            // Look-up a model instance by its id.
             var model = this._models[model_id];
             if (model !== undefined && model.id == model_id) {
                 return model;
             }
             return null;
         };
 
         WidgetManager.prototype._handle_comm_open = function (comm, msg) {
+            // Handle when a comm is opened.
             var model_id = comm.comm_id;
             var widget_type_name = msg.content.target_name;
             var widget_model = new WidgetManager._model_types[widget_type_name](this, model_id, comm);
             this._models[model_id] = widget_model;
         };
         
         IPython.WidgetManager = WidgetManager;
         return IPython.WidgetManager;
     });
 }());

IPython/html/static/notebook/js/widgets/widget.js

@@ -1,407 +1,407 b''
 //----------------------------------------------------------------------------
 //  Copyright (C) 2013 The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // Base Widget Model and View classes
 //============================================================================
 
 /**
  * @module IPython
  * @namespace IPython
  **/
 
 define(["notebook/js/widgetmanager",
         "underscore",
         "backbone"], 
 function(WidgetManager, Underscore, Backbone){
 
     var WidgetModel = Backbone.Model.extend({
         constructor: function (widget_manager, model_id, comm) {
             // Construcctor
             //
             // Creates a WidgetModel instance.
             //
             // Parameters
             // ----------
             // widget_manager : WidgetManager instance
             // model_id : string
             //      An ID unique to this model.
             // comm : Comm instance (optional)
             this.widget_manager = widget_manager;
             this.pending_msgs = 0;
             this.msg_throttle = 2;
             this.msg_buffer = null;
             this.key_value_lock = null;
             this.id = model_id;
             this.views = [];
 
             if (comm !== undefined) {
                 // Remember comm associated with the model.
                 this.comm = comm;
                 comm.model = this;
 
                 // Hook comm messages up to model.
                 comm.on_close($.proxy(this._handle_comm_closed, this));
                 comm.on_msg($.proxy(this._handle_comm_msg, this));
             }
             return Backbone.Model.apply(this);
         },
 
         send: function (content, callbacks) {
             // Send a custom msg over the comm.
             if (this.comm !== undefined) {
                 var data = {method: 'custom', content: content};
                 this.comm.send(data, callbacks);
             }
         },
 
         _handle_comm_closed: function (msg) {
             // Handle when a widget is closed.
             this.trigger('comm:close');
             delete this.comm.model; // Delete ref so GC will collect widget model.
             delete this.comm;
             delete this.model_id; // Delete id from model so widget manager cleans up.
             // TODO: Handle deletion, like this.destroy(), and delete views, etc.
         },
 
         _handle_comm_msg: function (msg) {
             // Handle incoming comm msg.
             var method = msg.content.data.method;
             switch (method) {
                 case 'update':
                     this.apply_update(msg.content.data.state);
                     break;
                 case 'custom':
                     this.trigger('msg:custom', msg.content.data.content);
                     break;
                 case 'display':
                     this.widget_manager.display_view(msg, this);
                     break;
             }
         },
 
         apply_update: function (state) {
             // Handle when a widget is updated via the python side.
             _.each(state, function(value, key) {
                 this.key_value_lock = [key, value];
                 try {
                     this.set(key, this._unpack_models(value));
                 } finally {
                     this.key_value_lock = null;
                 }
             });
         },
 
         _handle_status: function (msg, callbacks) {
             // Handle status msgs.
 
             // execution_state : ('busy', 'idle', 'starting')
             if (this.comm !== undefined) {
                 if (msg.content.execution_state ==='idle') {
                     // Send buffer if this message caused another message to be
                     // throttled.
                     if (this.msg_buffer !== null &&
                         this.msg_throttle === this.pending_msgs) {
                         var data = {method: 'backbone', sync_method: 'update', sync_data: this.msg_buffer};
                         this.comm.send(data, callbacks);  
                         this.msg_buffer = null;
                     } else {
                         --this.pending_msgs;
                     }
                 }
             }
         },
 
         callbacks: function(view) {
             // Create msg callbacks for a comm msg.
             var callbacks = this.widget_manager.callbacks(view);
 
             if (callbacks.iopub === undefined) {
                 callbacks.iopub = {};
             }
 
             var that = this;
             callbacks.iopub.status = function (msg) {
                 that._handle_status(msg, callbacks);
             }
             return callbacks;
         },
 
         sync: function (method, model, options) {
+            // Handle sync to the back-end.  Called when a model.save() is called.
 
             // Make sure a comm exists.
             var error = options.error || function() {
                 console.error('Backbone sync error:', arguments);
             }
             if (this.comm === undefined) {
                 error();
                 return false;
             }
 
             // Delete any key value pairs that the back-end already knows about.
             var attrs = (method === 'patch') ? options.attrs : model.toJSON(options);
             if (this.key_value_lock !== null) {
                 var key = this.key_value_lock[0];
                 var value = this.key_value_lock[1];
                 if (attrs[key] === value) {
                     delete attrs[key];
                 }
             }
 
             // Only sync if there are attributes to send to the back-end.
             if (attr.length > 0) {
                 var callbacks = options.callbacks || {};
                 if (this.pending_msgs >= this.msg_throttle) {
                     // The throttle has been exceeded, buffer the current msg so
                     // it can be sent once the kernel has finished processing 
                     // some of the existing messages.
                     
                     // Combine updates if it is a 'patch' sync, otherwise replace updates
                     switch (method) {
                         case 'patch':
                             this.msg_buffer = $.extend(this.msg_buffer || {}, attrs);
                             break;
                         case 'update':
                         case 'create':
                             this.msg_buffer = attrs;
                             break;
                         default:
                             error();
                             return false;
                     }
                     this.msg_buffer_callbacks = callbacks;
 
                 } else {
                     // We haven't exceeded the throttle, send the message like 
                     // normal.  If this is a patch operation, just send the 
                     // changes.
                     var data = {method: 'backbone', sync_data: attrs};
                     this.comm.send(data, callbacks);
                     this.pending_msgs++;
                 }
             }
             // Since the comm is a one-way communication, assume the message 
             // arrived.  Don't call success since we don't have a model back from the server
             // this means we miss out on the 'sync' event.
         },
 
         save_changes: function(callbacks) {
             // Push this model's state to the back-end
             //
             // This invokes a Backbone.Sync.
             this.save(this.changedAttributes(), {patch: true, callbacks: callbacks});
         },
 
         _pack_models: function(value) {
             // Replace models with model ids recursively.
             if (value instanceof Backbone.Model) {
                 return value.id;
             } else if (value instanceof Object) {
                 var packed = {};
                 _.each(value, function(sub_value, key) {
                     packed[key] = this._pack_models(sub_value);
                 });
                 return packed;
             } else {
                 return value;
             }
         },
 
         _unpack_models: function(value) {
             // Replace model ids with models recursively.
             if (value instanceof Object) {
                 var unpacked = {};
                 _.each(value, function(sub_value, key) {
                     unpacked[key] = this._unpack_models(sub_value);
                 });
                 return unpacked;
             } else {
                 var model = this.widget_manager.get_model(value);
                 if (model !== null) {
                     return model;
                 } else {
                     return value;
                 }
             }
         },
 
     });
     WidgetManager.register_widget_model('WidgetModel', WidgetModel);
 
 
     var WidgetView = Backbone.View.extend({
         initialize: function(parameters) {
             // Public constructor.
             this.model.on('change',this.update,this);
             this.options = parameters.options;
             this.child_views = [];
             this.model.views.push(this);
         },
 
         update: function(){
             // Triggered on model change.
             //
             // Update view to be consistent with this.model
         },
 
         create_child_view: function(child_model, options) {
             // Create and return a child view.
             //
             // -given a model and (optionally) a view name if the view name is 
             // not given, it defaults to the model's default view attribute.
         
             // TODO: this is hacky, and makes the view depend on this cell attribute and widget manager behavior
             // it would be great to have the widget manager add the cell metadata
             // to the subview without having to add it here.
             var child_view = this.model.widget_manager.create_view(child_model, options || {});
             this.child_views[child_model.id] = child_view;
             return child_view;
         },
 
         delete_child_view: function(child_model, options) {
             // Delete a child view that was previously created using create_child_view.
             var view = this.child_views[child_model.id];
             if (view !== undefined) {
                 delete this.child_views[child_model.id];
                 view.remove();    
             }
         },
 
         do_diff: function(old_list, new_list, removed_callback, added_callback) {
             // Difference a changed list and call remove and add callbacks for 
             // each removed and added item in the new list.
             //
             // Parameters
             // ----------
             // old_list : array
             // new_list : array
             // removed_callback : Callback(item)
             //      Callback that is called for each item removed.
             // added_callback : Callback(item)
             //      Callback that is called for each item added.
 
 
             // removed items
             _.each(_.difference(old_list, new_list), function(item, index, list) {
                 removed_callback(item);
             }, this);
 
             // added items
             _.each(_.difference(new_list, old_list), function(item, index, list) {
                 added_callback(item);
             }, this);
         },
 
         callbacks: function(){
             // Create msg callbacks for a comm msg.
             return this.model.callbacks(this);
         },
 
         render: function(){
             // Render the view.
             //
             // By default, this is only called the first time the view is created
         },
 
         send: function (content) {
             // Send a custom msg associated with this view.
             this.model.send(content, this.callbacks());
         },
 
         touch: function () {
             this.model.save_changes(this.callbacks());
         },
-
     });
 
 
     var DOMWidgetView = WidgetView.extend({
         initialize: function (options) {
             // Public constructor
 
             // In the future we may want to make changes more granular 
             // (e.g., trigger on visible:change).
             this.model.on('change', this.update, this);
             this.model.on('msg:custom', this.on_msg, this);
             DOMWidgetView.__super__.initialize.apply(this, arguments);
         },
         
         on_msg: function(msg) {
             // Handle DOM specific msgs.
             switch(msg.msg_type) {
                 case 'add_class':
                     this.add_class(msg.selector, msg.class_list);
                     break;
                 case 'remove_class':
                     this.remove_class(msg.selector, msg.class_list);
                     break;
             }
         },
 
         add_class: function (selector, class_list) {
             // Add a DOM class to an element.
             this._get_selector_element(selector).addClass(class_list);
         },
         
         remove_class: function (selector, class_list) {
             // Remove a DOM class from an element.
             this._get_selector_element(selector).removeClass(class_list);
         },
     
         update: function () {
             // Update the contents of this view
             //
             // Called when the model is changed.  The model may have been 
             // changed by another view or by a state update from the back-end.
             //      The very first update seems to happen before the element is 
             // finished rendering so we use setTimeout to give the element time 
             // to render
             var e = this.$el;
             var visible = this.model.get('visible');
             setTimeout(function() {e.toggle(visible)},0);
      
             var css = this.model.get('_css');
             if (css === undefined) {return;}
             _.each(css, function(css_traits, selector){
                 // Apply the css traits to all elements that match the selector.
                 var elements = this._get_selector_element(selector);
                 if (elements.length > 0) {
                     _.each(css_traits, function(css_value, css_key){
                         elements.css(css_key, css_value);
                     });
                 }
             });
                     
         },
 
         _get_selector_element: function (selector) {
             // Get the elements via the css selector.  
 
             // If the selector is blank, apply the style to the $el_to_style 
             // element.  If the $el_to_style element is not defined, use apply 
             // the style to the view's element.
             var elements;
             if (selector === undefined || selector === null || selector === '') {
                 if (this.$el_to_style === undefined) {
                     elements = this.$el;
                 } else {
                     elements = this.$el_to_style;
                 }
             } else {
                 elements = this.$el.find(selector);
             }
             return elements;
         },
     });
 
     IPython.WidgetModel = WidgetModel;
     IPython.WidgetView = WidgetView;
     IPython.DOMWidgetView = DOMWidgetView;
 
     // Pass through WidgetManager namespace.
     return WidgetManager;
 });