Backport PR #5668: allow async output on the most recent request

Keeps track of the most recent request, so async output is still allowed

closes  #5407

IPython/html/static/services/kernels/js/kernel.js

@@ -1,602 +1,622 b''
-//----------------------------------------------------------------------------
-//  Copyright (C) 2008-2011  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.
-//----------------------------------------------------------------------------
+// Copyright (c) IPython Development Team.
+// Distributed under the terms of the Modified BSD License.
 
 //============================================================================
 // Kernel
 //============================================================================
 
 /**
  * @module IPython
  * @namespace IPython
  * @submodule Kernel
  */
 
 var IPython = (function (IPython) {
     "use strict";
     
     var utils = IPython.utils;
 
     // Initialization and connection.
     /**
      * A Kernel Class to communicate with the Python kernel
      * @Class Kernel
      */
     var Kernel = function (kernel_service_url) {
         this.kernel_id = null;
         this.shell_channel = null;
         this.iopub_channel = null;
         this.stdin_channel = null;
         this.kernel_service_url = kernel_service_url;
         this.running = false;
         this.username = "username";
         this.session_id = utils.uuid();
         this._msg_callbacks = {};
 
         if (typeof(WebSocket) !== 'undefined') {
             this.WebSocket = WebSocket;
         } else if (typeof(MozWebSocket) !== 'undefined') {
             this.WebSocket = MozWebSocket;
         } else {
             alert('Your browser does not have WebSocket support, please try Chrome, Safari or Firefox ≥ 6. Firefox 4 and 5 are also supported by you have to enable WebSockets in about:config.');
         }
         
         this.bind_events();
         this.init_iopub_handlers();
         this.comm_manager = new IPython.CommManager(this);
         this.widget_manager = new IPython.WidgetManager(this.comm_manager);
+        
+        this.last_msg_id = null;
+        this.last_msg_callbacks = {};
     };
 
 
     Kernel.prototype._get_msg = function (msg_type, content, metadata) {
         var msg = {
             header : {
                 msg_id : utils.uuid(),
                 username : this.username,
                 session : this.session_id,
                 msg_type : msg_type
             },
             metadata : metadata || {},
             content : content,
             parent_header : {}
         };
         return msg;
     };
     
     Kernel.prototype.bind_events = function () {
         var that = this;
         $([IPython.events]).on('send_input_reply.Kernel', function(evt, data) { 
             that.send_input_reply(data);
         });
     };
     
     // Initialize the iopub handlers
     
     Kernel.prototype.init_iopub_handlers = function () {
         var output_types = ['stream', 'display_data', 'pyout', 'pyerr'];
         this._iopub_handlers = {};
         this.register_iopub_handler('status', $.proxy(this._handle_status_message, this));
         this.register_iopub_handler('clear_output', $.proxy(this._handle_clear_output, this));
         
         for (var i=0; i < output_types.length; i++) {
             this.register_iopub_handler(output_types[i], $.proxy(this._handle_output_message, this));
         }
     };
 
     /**
      * Start the Python kernel
      * @method start
      */
     Kernel.prototype.start = function (params) {
         params = params || {};
         if (!this.running) {
             var qs = $.param(params);
             $.post(utils.url_join_encode(this.kernel_service_url) + '?' + qs,
                 $.proxy(this._kernel_started, this),
                 'json'
             );
         }
     };
 
     /**
      * Restart the python kernel.
      *
      * Emit a 'status_restarting.Kernel' event with
      * the current object as parameter
      *
      * @method restart
      */
     Kernel.prototype.restart = function () {
         $([IPython.events]).trigger('status_restarting.Kernel', {kernel: this});
         if (this.running) {
             this.stop_channels();
             $.post(utils.url_join_encode(this.kernel_url, "restart"),
                 $.proxy(this._kernel_started, this),
                 'json'
             );
         }
     };
 
 
     Kernel.prototype._kernel_started = function (json) {
         console.log("Kernel started: ", json.id);
         this.running = true;
         this.kernel_id = json.id;
         // trailing 's' in https will become wss for secure web sockets
         this.ws_host = location.protocol.replace('http', 'ws') + "//" + location.host;
         this.kernel_url = utils.url_path_join(this.kernel_service_url, this.kernel_id);
         this.start_channels();
     };
 
 
     Kernel.prototype._websocket_closed = function(ws_url, early) {
         this.stop_channels();
         $([IPython.events]).trigger('websocket_closed.Kernel',
             {ws_url: ws_url, kernel: this, early: early}
         );
     };
 
     /**
      * Start the `shell`and `iopub` channels.
      * Will stop and restart them if they already exist.
      *
      * @method start_channels
      */
     Kernel.prototype.start_channels = function () {
         var that = this;
         this.stop_channels();
         var ws_host_url = this.ws_host + this.kernel_url;
         console.log("Starting WebSockets:", ws_host_url);
         this.shell_channel = new this.WebSocket(
             this.ws_host + utils.url_join_encode(this.kernel_url, "shell")
         );
         this.stdin_channel = new this.WebSocket(
             this.ws_host + utils.url_join_encode(this.kernel_url, "stdin")
         );
         this.iopub_channel = new this.WebSocket(
             this.ws_host + utils.url_join_encode(this.kernel_url, "iopub")
         );
         
         var already_called_onclose = false; // only alert once
         var ws_closed_early = function(evt){
             if (already_called_onclose){
                 return;
             }
             already_called_onclose = true;
             if ( ! evt.wasClean ){
                 that._websocket_closed(ws_host_url, true);
             }
         };
         var ws_closed_late = function(evt){
             if (already_called_onclose){
                 return;
             }
             already_called_onclose = true;
             if ( ! evt.wasClean ){
                 that._websocket_closed(ws_host_url, false);
             }
         };
         var channels = [this.shell_channel, this.iopub_channel, this.stdin_channel];
         for (var i=0; i < channels.length; i++) {
             channels[i].onopen = $.proxy(this._ws_opened, this);
             channels[i].onclose = ws_closed_early;
         }
         // switch from early-close to late-close message after 1s
         setTimeout(function() {
             for (var i=0; i < channels.length; i++) {
                 if (channels[i] !== null) {
                     channels[i].onclose = ws_closed_late;
                 }
             }
         }, 1000);
         this.shell_channel.onmessage = $.proxy(this._handle_shell_reply, this);
         this.iopub_channel.onmessage = $.proxy(this._handle_iopub_message, this);
         this.stdin_channel.onmessage = $.proxy(this._handle_input_request, this);
     };
 
     /**
      * Handle a websocket entering the open state
      * sends session and cookie authentication info as first message.
      * Once all sockets are open, signal the Kernel.status_started event.
      * @method _ws_opened
      */
     Kernel.prototype._ws_opened = function (evt) {
         // send the session id so the Session object Python-side
         // has the same identity
         evt.target.send(this.session_id + ':' + document.cookie);
         
         var channels = [this.shell_channel, this.iopub_channel, this.stdin_channel];
         for (var i=0; i < channels.length; i++) {
             // if any channel is not ready, don't trigger event.
             if ( !channels[i].readyState ) return;
         }
         // all events ready, trigger started event.
         $([IPython.events]).trigger('status_started.Kernel', {kernel: this});
     };
     
     /**
      * Stop the websocket channels.
      * @method stop_channels
      */
     Kernel.prototype.stop_channels = function () {
         var channels = [this.shell_channel, this.iopub_channel, this.stdin_channel];
         for (var i=0; i < channels.length; i++) {
             if ( channels[i] !== null ) {
                 channels[i].onclose = null;
                 channels[i].close();
             }
         }
         this.shell_channel = this.iopub_channel = this.stdin_channel = null;
     };
 
     // Main public methods.
     
     // send a message on the Kernel's shell channel
     Kernel.prototype.send_shell_message = function (msg_type, content, callbacks, metadata) {
         var msg = this._get_msg(msg_type, content, metadata);
         this.shell_channel.send(JSON.stringify(msg));
         this.set_callbacks_for_msg(msg.header.msg_id, callbacks);
         return msg.header.msg_id;
     };
 
     /**
      * Get kernel info
      *
      * @param callback {function}
      * @method object_info
      *
      * When calling this method, pass a callback function that expects one argument.
      * The callback will be passed the complete `kernel_info_reply` message documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#kernel-info)
      */
     Kernel.prototype.kernel_info = function (callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         return this.send_shell_message("kernel_info_request", {}, callbacks);
     };
 
     /**
      * Get info on an object
      *
      * @param objname {string}
      * @param callback {function}
      * @method object_info
      *
      * When calling this method, pass a callback function that expects one argument.
      * The callback will be passed the complete `object_info_reply` message documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#object-information)
      */
     Kernel.prototype.object_info = function (objname, callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         
         if (typeof(objname) !== null && objname !== null) {
             var content = {
                 oname : objname.toString(),
                 detail_level : 0,
             };
             return this.send_shell_message("object_info_request", content, callbacks);
         }
         return;
     };
 
     /**
      * Execute given code into kernel, and pass result to callback.
      *
      * @async
      * @method execute
      * @param {string} code
      * @param [callbacks] {Object} With the following keys (all optional)
      *      @param callbacks.shell.reply {function}
      *      @param callbacks.shell.payload.[payload_name] {function}
      *      @param callbacks.iopub.output {function}
      *      @param callbacks.iopub.clear_output {function}
      *      @param callbacks.input {function}
      * @param {object} [options]
      *      @param [options.silent=false] {Boolean}
      *      @param [options.user_expressions=empty_dict] {Dict}
      *      @param [options.user_variables=empty_list] {List od Strings}
      *      @param [options.allow_stdin=false] {Boolean} true|false
      *
      * @example
      *
      * The options object should contain the options for the execute call. Its default
      * values are:
      *
      *      options = {
      *        silent : true,
      *        user_variables : [],
      *        user_expressions : {},
      *        allow_stdin : false
      *      }
      *
      * When calling this method pass a callbacks structure of the form:
      *
      *      callbacks = {
      *       shell : {
      *         reply : execute_reply_callback,
      *         payload : {
      *           set_next_input : set_next_input_callback,
      *         }
      *       },
      *       iopub : {
      *         output : output_callback,
      *         clear_output : clear_output_callback,
      *       },
      *       input : raw_input_callback
      *      }
      *
      * Each callback will be passed the entire message as a single arugment.
      * Payload handlers will be passed the corresponding payload and the execute_reply message.
      */
     Kernel.prototype.execute = function (code, callbacks, options) {
 
         var content = {
             code : code,
             silent : true,
             store_history : false,
             user_variables : [],
             user_expressions : {},
             allow_stdin : false
         };
         callbacks = callbacks || {};
         if (callbacks.input !== undefined) {
             content.allow_stdin = true;
         }
         $.extend(true, content, options);
         $([IPython.events]).trigger('execution_request.Kernel', {kernel: this, content:content});
         return this.send_shell_message("execute_request", content, callbacks);
     };
 
     /**
      * When calling this method, pass a function to be called with the `complete_reply` message
      * as its only argument when it arrives.
      *
      * `complete_reply` is documented
      * [here](http://ipython.org/ipython-doc/dev/development/messaging.html#complete)
      *
      * @method complete
      * @param line {integer}
      * @param cursor_pos {integer}
      * @param callback {function}
      *
      */
     Kernel.prototype.complete = function (line, cursor_pos, callback) {
         var callbacks;
         if (callback) {
             callbacks = { shell : { reply : callback } };
         }
         var content = {
             text : '',
             line : line,
             block : null,
             cursor_pos : cursor_pos
         };
         return this.send_shell_message("complete_request", content, callbacks);
     };
 
 
     Kernel.prototype.interrupt = function () {
         if (this.running) {
             $([IPython.events]).trigger('status_interrupting.Kernel', {kernel: this});
             $.post(utils.url_join_encode(this.kernel_url, "interrupt"));
         }
     };
 
 
     Kernel.prototype.kill = function () {
         if (this.running) {
             this.running = false;
             var settings = {
                 cache : false,
                 type : "DELETE"
             };
             $.ajax(utils.url_join_encode(this.kernel_url), settings);
         }
     };
 
     Kernel.prototype.send_input_reply = function (input) {
         var content = {
             value : input,
         };
         $([IPython.events]).trigger('input_reply.Kernel', {kernel: this, content:content});
         var msg = this._get_msg("input_reply", content);
         this.stdin_channel.send(JSON.stringify(msg));
         return msg.header.msg_id;
     };
 
 
     // Reply handlers
 
     Kernel.prototype.register_iopub_handler = function (msg_type, callback) {
         this._iopub_handlers[msg_type] = callback;
     };
 
     Kernel.prototype.get_iopub_handler = function (msg_type) {
         // get iopub handler for a specific message type
         return this._iopub_handlers[msg_type];
     };
 
 
     Kernel.prototype.get_callbacks_for_msg = function (msg_id) {
         // get callbacks for a specific message
-        return this._msg_callbacks[msg_id];
+        if (msg_id == this.last_msg_id) {
+            return this.last_msg_callbacks;
+        } else {
+            return this._msg_callbacks[msg_id];
+        }
     };
 
 
     Kernel.prototype.clear_callbacks_for_msg = function (msg_id) {
         if (this._msg_callbacks[msg_id] !== undefined ) {
             delete this._msg_callbacks[msg_id];
         }
     };
     
+    Kernel.prototype._finish_shell = function (msg_id) {
+        var callbacks = this._msg_callbacks[msg_id];
+        if (callbacks !== undefined) {
+            callbacks.shell_done = true;
+            if (callbacks.iopub_done) {
+                this.clear_callbacks_for_msg(msg_id);
+            }
+        }
+    };
+
+    Kernel.prototype._finish_iopub = function (msg_id) {
+        var callbacks = this._msg_callbacks[msg_id];
+        if (callbacks !== undefined) {
+            callbacks.iopub_done = true;
+            if (!callbacks.shell_done) {
+                this.clear_callbacks_for_msg(msg_id);
+            }
+        }
+    };
+    
     /* Set callbacks for a particular message.
      * Callbacks should be a struct of the following form:
      * shell : {
      * 
      * }
     
      */
     Kernel.prototype.set_callbacks_for_msg = function (msg_id, callbacks) {
+        this.last_msg_id = msg_id;
         if (callbacks) {
             // shallow-copy mapping, because we will modify it at the top level
-            var cbcopy = this._msg_callbacks[msg_id] = {};
+            var cbcopy = this._msg_callbacks[msg_id] = this.last_msg_callbacks = {};
             cbcopy.shell = callbacks.shell;
             cbcopy.iopub = callbacks.iopub;
             cbcopy.input = callbacks.input;
-            this._msg_callbacks[msg_id] = cbcopy;
+            cbcopy.shell_done = (!callbacks.shell);
+            cbcopy.iopub_done = (!callbacks.iopub);
+        } else {
+            this.last_msg_callbacks = {};
         }
     };
 
 
     Kernel.prototype._handle_shell_reply = function (e) {
         var reply = $.parseJSON(e.data);
         $([IPython.events]).trigger('shell_reply.Kernel', {kernel: this, reply:reply});
         var content = reply.content;
         var metadata = reply.metadata;
         var parent_id = reply.parent_header.msg_id;
         var callbacks = this.get_callbacks_for_msg(parent_id);
         if (!callbacks || !callbacks.shell) {
             return;
         }
         var shell_callbacks = callbacks.shell;
         
-        // clear callbacks on shell
-        delete callbacks.shell;
-        delete callbacks.input;
-        if (!callbacks.iopub) {
-            this.clear_callbacks_for_msg(parent_id);
-        }
+        // signal that shell callbacks are done
+        this._finish_shell(parent_id);
         
         if (shell_callbacks.reply !== undefined) {
             shell_callbacks.reply(reply);
         }
         if (content.payload && shell_callbacks.payload) {
             this._handle_payloads(content.payload, shell_callbacks.payload, reply);
         }
     };
 
 
     Kernel.prototype._handle_payloads = function (payloads, payload_callbacks, msg) {
         var l = payloads.length;
         // Payloads are handled by triggering events because we don't want the Kernel
         // to depend on the Notebook or Pager classes.
         for (var i=0; i<l; i++) {
             var payload = payloads[i];
             var callback = payload_callbacks[payload.source];
             if (callback) {
                 callback(payload, msg);
             }
         }
     };
 
     Kernel.prototype._handle_status_message = function (msg) {
         var execution_state = msg.content.execution_state;
         var parent_id = msg.parent_header.msg_id;
         
         // dispatch status msg callbacks, if any
         var callbacks = this.get_callbacks_for_msg(parent_id);
         if (callbacks && callbacks.iopub && callbacks.iopub.status) {
             try {
                 callbacks.iopub.status(msg);
             } catch (e) {
                 console.log("Exception in status msg handler", e, e.stack);
             }
         }
         
         if (execution_state === 'busy') {
             $([IPython.events]).trigger('status_busy.Kernel', {kernel: this});
         } else if (execution_state === 'idle') {
-            // clear callbacks on idle, there can be no more
-            if (callbacks !== undefined) {
-                delete callbacks.iopub;
-                delete callbacks.input;
-                if (!callbacks.shell) {
-                    this.clear_callbacks_for_msg(parent_id);
-                }
-            }
+            // signal that iopub callbacks are (probably) done
+            // async output may still arrive,
+            // but only for the most recent request
+            this._finish_iopub(parent_id);
+            
             // trigger status_idle event
             $([IPython.events]).trigger('status_idle.Kernel', {kernel: this});
         } else if (execution_state === 'restarting') {
             // autorestarting is distinct from restarting,
             // in that it means the kernel died and the server is restarting it.
             // status_restarting sets the notification widget,
             // autorestart shows the more prominent dialog.
             $([IPython.events]).trigger('status_autorestarting.Kernel', {kernel: this});
             $([IPython.events]).trigger('status_restarting.Kernel', {kernel: this});
         } else if (execution_state === 'dead') {
             this.stop_channels();
             $([IPython.events]).trigger('status_dead.Kernel', {kernel: this});
         }
     };
     
     
     // handle clear_output message
     Kernel.prototype._handle_clear_output = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
         if (!callbacks || !callbacks.iopub) {
             return;
         }
         var callback = callbacks.iopub.clear_output;
         if (callback) {
             callback(msg);
         }
     };
 
 
     // handle an output message (pyout, display_data, etc.)
     Kernel.prototype._handle_output_message = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
         if (!callbacks || !callbacks.iopub) {
             return;
         }
         var callback = callbacks.iopub.output;
         if (callback) {
             callback(msg);
         }
     };
 
     // dispatch IOPub messages to respective handlers.
     // each message type should have a handler.
     Kernel.prototype._handle_iopub_message = function (e) {
         var msg = $.parseJSON(e.data);
 
         var handler = this.get_iopub_handler(msg.header.msg_type);
         if (handler !== undefined) {
             handler(msg);
         }
     };
 
 
     Kernel.prototype._handle_input_request = function (e) {
         var request = $.parseJSON(e.data);
         var header = request.header;
         var content = request.content;
         var metadata = request.metadata;
         var msg_type = header.msg_type;
         if (msg_type !== 'input_request') {
             console.log("Invalid input request!", request);
             return;
         }
         var callbacks = this.get_callbacks_for_msg(request.parent_header.msg_id);
         if (callbacks) {
             if (callbacks.input) {
                 callbacks.input(request);
             }
         }
     };
 
 
     IPython.Kernel = Kernel;
 
     return IPython;
 
 }(IPython));