Cleaned up _make_callbacks method of widget model class

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

@@ -1,587 +1,593 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
  */
 
 "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(["components/underscore/underscore-min",
          "components/backbone/backbone-min",
         ], function(underscore, backbone){
 
 
     //--------------------------------------------------------------------
     // WidgetModel class
     //--------------------------------------------------------------------
     var WidgetModel = Backbone.Model.extend({
         constructor: function(comm_manager, comm, widget_manager) {
             this.comm_manager = comm_manager;
             this.widget_manager = widget_manager;
             this.pending_msgs = 0;
             this.msg_throttle = 3;
             this.msg_buffer = null;
             this.views = {};
 
             // 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);
         },
 
 
         update_other_views: function(caller) {
             this.last_modified_view = caller;
             this.save(this.changedAttributes(), {patch: true});
 
             for (var cell in this.views) {
                 var views = this.views[cell];
                 for (var view_index in views) {
                     var view = views[view_index];
                     if (view !== caller) {
                         view.update();    
                     }
                 }
             }
         },
     
         send: function(content) {
 
             // Used the last modified view as the sender of the message.  This
             // will insure that any python code triggered by the sent message
             // can create and display widgets and output.
             var cell = null;
             if (this.last_modified_view != undefined && 
                 this.last_modified_view.cell != undefined) {
                 cell = this.last_modified_view.cell;
             }
             var callbacks = this._make_callbacks(cell);
             var data = {custom_content: content};
             this.comm.send(data, callbacks);   
         },
 
 
         on_view_displayed: function (callback) {
             this._view_displayed_callback = callback;
         },
 
 
         on_close: function (callback) {
             this._close_callback = callback;
         },
 
 
         on_msg: function (callback) {
             this._msg_callback = callback;
         },
 
 
         _handle_custom_msg: function (content) {
             if (this._msg_callback) {
                 try {
                     this._msg_callback(content);
                 } catch (e) {
                     console.log("Exception in widget model msg callback", e, content);
                 }
             }
         },
 
 
         // Handle when a widget is closed.
         _handle_comm_closed: function (msg) {
             for (var cell in this.views) {
                 var views = this.views[cell];
                 for (var view_index in views) {
                     var view = views[view_index];
                     view.remove();
                 }
             }
             delete this.comm.model; // Delete ref so GC will collect widget model.
         },
 
 
         // Handle incomming comm msg.
         _handle_comm_msg: function (msg) {
             var method = msg.content.data.method;
             switch (method){
                 case 'display':
 
                     // Try to get the cell.
                     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 {
                         this._display_view(msg.content.data.view_name, 
                         msg.content.data.parent,
                         cell);
                     }
                     break;
                 case 'update':
                     this._handle_update(msg.content.data.state);
                     break;
                 case 'custom':
                     this._handle_custom_msg(msg.content.data.custom_content);
                     break;
             }
         },
 
 
         // Handle when a widget is updated via the python side.
         _handle_update: function (state) {
             this.updating = true;
             try {
                 for (var key in state) {
                     if (state.hasOwnProperty(key)) {
                         if (key == "_css"){
 
                             // Set the css value of the model as an attribute
                             // instead of a backbone trait because we are only 
                             // interested in backend css -> frontend css.  In
                             // other words, if the css dict changes in the
                             // frontend, we don't need to push the changes to
                             // the backend.
                             this.css = state[key];
                         } else {
                             this.set(key, state[key]); 
                         }
                     }
                 }
                 this.id = this.comm.comm_id;
                 this.save();
             } finally {
                 this.updating = false;
             }
         },
 
 
         _handle_status: function (cell, msg) {
             //execution_state : ('busy', 'idle', 'starting')
             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 cell = this._get_msg_cell(msg.parent_header.msg_id);
                     var callbacks = this._make_callbacks(cell);
                     var data = {sync_method: 'update', sync_data: this.msg_buffer};
                     this.comm.send(data, callbacks);   
                     this.msg_buffer = null;
                 } else {
 
                     // Only decrease the pending message count if the buffer
                     // doesn't get flushed (sent).
                     --this.pending_msgs;
                 }
             }
         },
 
 
         // Custom syncronization logic.
         _handle_sync: function (method, options) {
             var model_json = this.toJSON();
 
             // Only send updated state if the state hasn't been changed 
             // during an update.
             if (!this.updating) {
                 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.
                     if (method=='patch') {
                         if (this.msg_buffer == null) {
                             this.msg_buffer = $.extend({}, model_json); // Copy
                         }
                         for (var attr in options.attrs) {
                             this.msg_buffer[attr] = options.attrs[attr];
                         }
                     } else {
                         this.msg_buffer = $.extend({}, model_json); // Copy
                     }
 
                 } else {
                     // We haven't exceeded the throttle, send the message like 
                     // normal.  If this is a patch operation, just send the 
                     // changes.
                     var send_json = model_json;
                     if (method=='patch') {
                         send_json = {};
                         for (var attr in options.attrs) {
                             send_json[attr] = options.attrs[attr];
                         }
                     }
 
                     var data = {sync_method: method, sync_data: send_json};
 
                     var cell = null;
                     if (this.last_modified_view != undefined && this.last_modified_view != null) {
                         cell = this.last_modified_view.cell;    
                     }
                     
                     var callbacks = this._make_callbacks(cell);
                     this.comm.send(data, callbacks);    
                     this.pending_msgs++;
                 }
             }
             
             // Since the comm is a one-way communication, assume the message 
             // arrived.
             return model_json;
         },
 
 
         _handle_view_displayed: function(view) {
             if (this._view_displayed_callback) {
                 try {
                     this._view_displayed_callback(view)
                 } catch (e) {
                     console.log("Exception in widget model view displayed callback", e, view, this);
                 }
             }
         },
 
 
         // Create view that represents the model.
         _display_view: function (view_name, parent_comm_id, cell) {
             var new_views = [];
 
             // Try creating and adding the view to it's parent.
             var displayed = false;
             if (parent_comm_id != undefined) {
                 var parent_comm = this.comm_manager.comms[parent_comm_id];
                 var parent_model = parent_comm.model;
                 var parent_views = parent_model.views[cell];
                 for (var parent_view_index in parent_views) {
                     var parent_view = parent_views[parent_view_index];
                     if (parent_view.display_child != undefined) {
                         var view = this._create_view(view_name, cell);
                         if (view != null) {
                             new_views.push(view);
                             parent_view.display_child(view);
                             displayed = true;
                             this._handle_view_displayed(view);
                         }
                     }
                 }
             }
 
             // If no parent view is defined or exists.  Add the view's 
             // element to cell's widget div.
             if (!displayed) {
                 var view = this._create_view(view_name, cell);
                 if (view != null) {
                     new_views.push(view);
 
                     if (cell.widget_subarea != undefined && cell.widget_subarea != null) {
                         cell.widget_area.show();
                         cell.widget_subarea.append(view.$el);
                         this._handle_view_displayed(view);
                     }
                 }
             }
 
             // Force the new view(s) to update their selves
             for (var view_index in new_views) {
                 var view = new_views[view_index];
                 view.update();
             }
         },
 
 
         // Create a view
         _create_view: function (view_name, cell) {
             var view_type = this.widget_manager.widget_view_types[view_name]; 
             if (view_type != undefined && view_type != null) {
                 var view = new view_type({model: this});
                 view.render();
                 if (this.views[cell]==undefined) {
                     this.views[cell] = []
                 }
                 this.views[cell].push(view);
                 view.cell = cell;
 
                 // Handle when the view element is remove from the page.
                 var that = this;
                 view.$el.on("remove", function(){ 
                     var index = that.views[cell].indexOf(view);
                     if (index > -1) {
                         that.views[cell].splice(index, 1);
                     }
                     view.remove(); // Clean-up view 
                     if (that.views[cell].length()==0) {
                         delete that.views[cell];
                     }
 
                     // Close the comm if there are no views left.
                     if (that.views.length()==0) {
                         if (that._close_callback) {
                             try {
                                 that._close_callback(that)
                             } catch (e) {
                                 console.log("Exception in widget model close callback", e, that);
                             }
                         }
                         that.comm.close();     
                         delete that.comm.model; // Delete ref so GC will collect widget model.
                     }
                 });
                 return view;    
             }
             return null;
         },
 
 
         // Build a callback dict.
         _make_callbacks: function (cell) {
             var callbacks = {};
-            if (cell != null && cell.output_area != undefined && cell.output_area != null) {
+            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 usign what is known
                 var that = this;
                 callbacks = {
                     iopub : {
-                        output : $.proxy(cell.output_area.handle_output, cell.output_area),
-                        clear_output : $.proxy(cell.output_area.handle_clear_output, cell.output_area),
+                        output : handle_output,
+                        clear_output : handle_clear_output,
+                        
                         status : function(msg){
                             that._handle_status(cell, msg);
                         },
 
                         // 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() {
-                            if (that.last_modified_view != undefined && 
-                                that.last_modified_view.cell != undefined) {
-                                return that.last_modified_view.cell;
-                            } else {
-                                return null
-                            }
+                            return cell;
                         },
                     },
                 };
             }
             return callbacks;
         },
 
 
         // Get the output area corresponding to the msg_id.
         // cell is an instance of IPython.Cell
         _get_msg_cell: function (msg_id) {
 
             // First, check to see if the msg was triggered by cell execution.
             var cell = this.widget_manager.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;
             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;
         },
 
     });
 
 
     //--------------------------------------------------------------------
     // WidgetView class
     //--------------------------------------------------------------------
     var WidgetView = Backbone.View.extend({
         
         initialize: function() {
             this.visible = true;
             this.model.on('change',this.update,this);
             this._add_class_calls = this.model.get('_add_class')[0];
             this._remove_class_calls = this.model.get('_remove_class')[0];
         },
         
         update: function() {
             if (this.model.get('visible') != undefined) {
                 if (this.visible != this.model.get('visible')) {
                     this.visible = this.model.get('visible');
                     if (this.visible) {
                         this.$el.show();
                     } else {
                         this.$el.hide();
                     }
                 }
             }
 
             if (this.model.css != undefined) {
                 for (var selector in this.model.css) {
                     if (this.model.css.hasOwnProperty(selector)) {
                         
                         // Apply the css traits to all elements that match the selector.
                         var elements = this._get_selector_element(selector);
                         if (elements.length > 0) {
                             var css_traits = this.model.css[selector];    
                             for (var css_key in css_traits) {
                                 if (css_traits.hasOwnProperty(css_key)) {
                                     elements.css(css_key, css_traits[css_key]);
                                 }
                             }
                         }
                     }
                 }
             }
 
             var add_class = this.model.get('_add_class');
             if (add_class != undefined){
                 var add_class_calls = add_class[0];
                 if (add_class_calls > this._add_class_calls) {
                     this._add_class_calls = add_class_calls;
                     var elements = this._get_selector_element(add_class[1]);
                     if (elements.length > 0) {
                         elements.addClass(add_class[2]);
                     }
                 }    
             }
 
             var remove_class = this.model.get('_remove_class');
             if (remove_class != undefined){
                 var remove_class_calls = remove_class[0];
                 if (remove_class_calls > this._remove_class_calls) {
                     this._remove_class_calls = remove_class_calls;
                     var elements = this._get_selector_element(remove_class[1]);
                     if (elements.length > 0) {
                         elements.removeClass(remove_class[2]);
                     }
                 }    
             }
         },
 
         _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 $el_to_style element is not defined, use apply the 
             // style to the view's element.
             var elements = this.$el.find(selector);
             if (selector=='') {
                 if (this.$el_to_style == undefined) {
                     elements = this.$el;
                 } else {
                     elements = this.$el_to_style;
                 }
             }
             return elements;
         },
     });
 
 
     //--------------------------------------------------------------------
     // WidgetManager class
     //--------------------------------------------------------------------
     var WidgetManager = function(){
         this.comm_manager = null;
         this.widget_model_types = {};
         this.widget_view_types = {};
         
         var that = this;
         Backbone.sync = function(method, model, options, error) {
             var result = model._handle_sync(method, options);
             if (options.success) {
               options.success(result);
             }
         }; 
     }
 
 
     WidgetManager.prototype.attach_comm_manager = function (comm_manager) {
         this.comm_manager = comm_manager;
 
         // Register already register widget model types with the comm manager.
         for (var widget_model_name in this.widget_model_types) {
             this.comm_manager.register_target(widget_model_name, $.proxy(this._handle_com_open, this));
         }
     }
 
 
     WidgetManager.prototype.register_widget_model = function (widget_model_name, widget_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.
         if (this.comm_manager!=null) {
             this.comm_manager.register_target(widget_model_name, $.proxy(this._handle_com_open, this));
         }
         this.widget_model_types[widget_model_name] = widget_model_type;
     }
 
 
     WidgetManager.prototype.register_widget_view = function (widget_view_name, widget_view_type) {
         this.widget_view_types[widget_view_name] = widget_view_type;
     }
 
 
     WidgetManager.prototype.get_msg_cell = function (msg_id) {
         if (IPython.notebook != undefined && IPython.notebook != null) {
             return IPython.notebook.get_msg_cell(msg_id);
         }
     }
     
     
     WidgetManager.prototype.on_create_widget = function (callback) {
         this._create_widget_callback = callback;
     }
 
 
     WidgetManager.prototype._handle_create_widget = function (widget_model) {
         if (this._create_widget_callback) {
             try {
                 this._create_widget_callback(widget_model);
             } catch (e) {
                 console.log("Exception in WidgetManager callback", e, widget_model);
             }
         }
     }
 
 
     WidgetManager.prototype._handle_com_open = function (comm, msg) {
         var widget_type_name = msg.content.target_name;
         var widget_model = new this.widget_model_types[widget_type_name](this.comm_manager, comm, this);
         this._handle_create_widget(widget_model);
     }
     
 
     //--------------------------------------------------------------------
     // Init code
     //--------------------------------------------------------------------
     IPython.WidgetManager = WidgetManager;
     IPython.WidgetModel = WidgetModel;
     IPython.WidgetView = WidgetView;
 
     if (IPython.widget_manager==undefined || IPython.widget_manager==null) {
         IPython.widget_manager = new WidgetManager();    
     }
     
     return IPython.widget_manager;
 });