GUAC-1172: Add Guacamole.Object and handlers for object-related instructions.

guacamole-common-js/src/main/webapp/modules/Object.js

@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2013 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+var Guacamole = Guacamole || {};
+
+/**
+ * An object used by the Guacamole client to house arbitrarily-many named
+ * input and output streams.
+ * 
+ * @constructor
+ * @param {Guacamole.Client} client
+ *     The client owning this object.
+ *
+ * @param {Number} index
+ *     The index of this object.
+ */
+Guacamole.Object = function(client, index) {
+
+    /**
+     * Reference to this Guacamole.Object.
+     *
+     * @private
+     * @type Guacamole.Object
+     */
+    var guacObject = this;
+
+    /**
+     * The callbacks associated with all pending input stream requests, if the
+     * default onbody handling is in use.
+     *
+     * @private
+     * @type Object.<String, Function[]>
+     *     Map of stream name to corresponding queue of callbacks. The queue of
+     *     callbacks is guaranteed to be in order of request.
+     */
+    var bodyCallbacks = {};
+
+    /**
+     * Removes and returns the callback at the head of the callback queue for
+     * the stream having the given name. If no such callbacks exist, null is
+     * returned.
+     *
+     * @private
+     * @param {String} name
+     *     The name of the stream to retrieve a callback for.
+     *
+     * @returns {Function}
+     *     The next callback associated with the stream having the given name,
+     *     or null if no such callback exists.
+     */
+    var dequeueBodyCallback = function dequeueBodyCallback(name) {
+
+        // If no callbacks defined, simply return null
+        var callbacks = bodyCallbacks[name];
+        if (!callbacks)
+            return null;
+
+        // Otherwise, pull off first callback, deleting the queue if empty
+        var callback = callbacks.shift();
+        if (callbacks.length === 0)
+            delete bodyCallbacks[name];
+
+        // Return found callback
+        return callback;
+
+    };
+
+    /**
+     * Adds the given callback to the tail of the callback queue for the stream
+     * having the given name.
+     *
+     * @private
+     * @param {String} name
+     *     The name of the stream to associate with the given callback.
+     *
+     * @param {Function} callback
+     *     The callback to add to the queue of the stream with the given name.
+     */
+    var enqueueBodyCallback = function enqueueBodyCallback(name, callback) {
+
+        // Get callback queue by name, creating first if necessary
+        var callbacks = bodyCallbacks[name];
+        if (!callbacks) {
+            callbacks = [];
+            bodyCallbacks[name] = callbacks;
+        }
+
+        // Add callback to end of queue
+        callbacks.push(callback);
+
+    };
+
+    /**
+     * The index of this object.
+     *
+     * @type Number
+     */
+    this.index = index;
+
+    /**
+     * Called when this object receives the body of a requested input stream.
+     * By default, all objects will invoke the callbacks provided to their
+     * requestInputStream() functions based on the name of the stream
+     * requested. This behavior can be overridden by specifying a different
+     * handler here.
+     *
+     * @event
+     * @param {Guacamole.InputStream} inputStream
+     *     The input stream of the received body.
+     *
+     * @param {String} mimetype
+     *     The mimetype of the data being received.
+     *
+     * @param {String} name
+     *     The name of the stream whose body has been received.
+     */
+    this.onbody = function defaultBodyHandler(inputStream, mimetype, name) {
+
+        // Call queued callback for the received body, if any
+        var callback = dequeueBodyCallback(name);
+        if (callback)
+            callback(inputStream, mimetype);
+
+    };
+
+    /**
+     * Called when this object is being undefined. Once undefined, no further
+     * communication involving this object may occur.
+     * 
+     * @event
+     */
+    this.onundefine = null;
+
+    /**
+     * Requests read access to the input stream having the given name. If
+     * successful, a new input stream will be created.
+     *
+     * @param {String} name
+     *     The name of the input stream to request.
+     *
+     * @param {Function} [bodyCallback]
+     *     The callback to invoke when the body of the requested input stream
+     *     is received. This callback will be provided a Guacamole.InputStream
+     *     and its mimetype as its two only arguments. If the onbody handler of
+     *     this object is overridden, this callback will not be invoked.
+     */
+    this.requestInputStream = function(name, bodyCallback) {
+
+        // Queue body callback if provided
+        if (bodyCallback)
+            queueBodyCallback(name, bodyCallback);
+
+        // Send request for input stream
+        client.requestObjectInputStream(guacObject.index, name);
+
+    };
+
+    /**
+     * Creates a new output stream associated with this object and having the
+     * given mimetype and name. The legality of a mimetype and name is dictated
+     * by the object itself.
+     *
+     * @param {String} mimetype
+     *     The mimetype of the data which will be sent to the output stream.
+     *
+     * @param {String} name
+     *     The defined name of an output stream within this object.
+     *
+     * @returns {Guacamole.OutputStream}
+     *     An output stream which will write blobs to the named output stream
+     *     of this object.
+     */
+    this.createOutputStream = function(mimetype, name) {
+        return client.createObjectOutputStream(guacObject.index, mimetype, name);
+    };
+
+};
+
+/**
+ * The reserved name denoting the root stream of any object. The contents of
+ * the root stream MUST be a JSON map of stream name to mimetype.
+ *
+ * @constant
+ * @type String
+ */
+Guacamole.Object.ROOT_STREAM = '/';