//----------------------------------------------------------------------------
// 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, _, Backbone){
var WidgetModel = Backbone.Model.extend({
constructor: function (widget_manager, model_id, comm) {
// Constructor
//
// 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._buffered_state_diff = {};
this.pending_msgs = 0;
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);
this.pending_msgs++;
}
},
_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.
_.each(this.views, function(view, i) {
view.remove();
});
},
_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.
var that = this;
_.each(state, function(value, key) {
that.key_value_lock = [key, value];
try {
WidgetModel.__super__.set.apply(that, [key, that._unpack_models(value)]);
} finally {
that.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.get('msg_throttle') || 3) === 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;
},
set: function(key, val, options) {
// Set a value.
var return_value = WidgetModel.__super__.set.apply(this, arguments);
// Backbone only remembers the diff of the most recent set()
// operation. Calling set multiple times in a row results in a
// loss of diff information. Here we keep our own running diff.
this._buffered_state_diff = $.extend(this._buffered_state_diff, this.changedAttributes() || {});
return return_value;
},
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.
attrs = this._pack_models(attrs);
if (_.size(attrs) > 0) {
// If this message was sent via backbone itself, it will not
// have any callbacks. It's important that we create callbacks
// so we can listen for status messages, etc...
var callbacks = options.callbacks || this.callbacks();
// Check throttle.
if (this.pending_msgs >= (this.get('msg_throttle') || 3)) {
// 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 = $.extend(this.msg_buffer || {}, attrs);
break;
case 'update':
case 'create':
this.msg_buffer = attrs;
break;
default:
error();
return false;
}
this.msg_buffer_callbacks = callbacks;
} else {
// We haven't exceeded the throttle, send the message like
// normal.
var data = {method: 'backbone', sync_data: attrs};
this.comm.send(data, callbacks);
this.pending_msgs++;
}
}
// Since the comm is a one-way communication, assume the message
// arrived. Don't call success since we don't have a model back from the server
// this means we miss out on the 'sync' event.
this._buffered_state_diff = {};
},
save_changes: function(callbacks) {
// Push this model's state to the back-end
//
// This invokes a Backbone.Sync.
this.save(this._buffered_state_diff, {patch: true, callbacks: callbacks});
},
_pack_models: function(value) {
// Replace models with model ids recursively.
if (value instanceof Backbone.Model) {
return value.id;
} else if ($.isArray(value)) {
var packed = [];
var that = this;
_.each(value, function(sub_value, key) {
packed.push(that._pack_models(sub_value));
});
return packed;
} else if (value instanceof Object) {
var packed = {};
var that = this;
_.each(value, function(sub_value, key) {
packed[key] = that._pack_models(sub_value);
});
return packed;
} else {
return value;
}
},
_unpack_models: function(value) {
// Replace model ids with models recursively.
if ($.isArray(value)) {
var unpacked = [];
var that = this;
_.each(value, function(sub_value, key) {
unpacked.push(that._unpack_models(sub_value));
});
return unpacked;
} else if (value instanceof Object) {
var unpacked = {};
var that = this;
_.each(value, function(sub_value, key) {
unpacked[key] = that._unpack_models(sub_value);
});
return unpacked;
} else {
var model = this.widget_manager.get_model(value);
if (model) {
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);
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;}
var that = this;
_.each(css, function(css_traits, selector){
// Apply the css traits to all elements that match the selector.
var elements = that._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 $el_to_style element is not defined, use apply
// the style to the view's element.
var elements;
if (!selector) {
if (this.$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;
});