GUAC-240: Read images received through "img" streams using a Guacamole.DataURIReader - appending to standard Blob objects is too slow.

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

@@ -897,12 +897,12 @@ Guacamole.Client = function(tunnel) {
 
             // Create stream
             var stream = streams[stream_index] = new Guacamole.InputStream(guac_client, stream_index);
-            var reader = new Guacamole.BlobReader(stream, mimetype);
+            var reader = new Guacamole.DataURIReader(stream, mimetype);
 
-            // Draw blob when stream is complete
+            // Draw image when stream is complete
             reader.onend = function drawImageBlob() {
                 display.setChannelMask(layer, channelMask);
-                display.drawBlob(layer, x, y, reader.getBlob());
+                display.draw(layer, x, y, reader.getURI());
             };
 
         },

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

@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2015 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 || {};
+
+/**
+ * A reader which automatically handles the given input stream, returning
+ * received blobs as a single data URI built over the course of the stream.
+ * Note that this object will overwrite any installed event handlers on the
+ * given Guacamole.InputStream.
+ * 
+ * @constructor
+ * @param {Guacamole.InputStream} stream
+ *     The stream that data will be read from.
+ */
+Guacamole.DataURIReader = function(stream, mimetype) {
+
+    /**
+     * Reference to this Guacamole.DataURIReader.
+     * @private
+     */
+    var guac_reader = this;
+
+    /**
+     * Current data URI.
+     *
+     * @type String
+     */
+    var uri = 'data:' + mimetype + ';base64,';
+
+    // Receive blobs as array buffers
+    stream.onblob = function dataURIReaderBlob(data) {
+
+        // Currently assuming data will ALWAYS be safe to simply append. This
+        // will not be true if the received base64 data encodes a number of
+        // bytes that isn't a multiple of three (as base64 expands in a ratio
+        // of exactly 3:4).
+        uri += data;
+
+    };
+
+    // Simply call onend when end received
+    stream.onend = function dataURIReaderEnd() {
+        if (guac_reader.onend)
+            guac_reader.onend();
+    };
+
+    /**
+     * Returns the data URI of all data received through the underlying stream
+     * thus far.
+     *
+     * @returns {String}
+     *     The data URI of all data received through the underlying stream thus
+     *     far.
+     */
+    this.getURI = function getURI() {
+        return uri;
+    };
+
+    /**
+     * Fired once this stream is finished and no further data will be written.
+     *
+     * @event
+     */
+    this.onend = null;
+
+};