Migrate to minify-maven-plugin and Google Closure Compiler.

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

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+/*
+ * 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 || {};
+
+/**
+ * Abstract audio channel which queues and plays arbitrary audio data.
+ * @constructor
+ */
+Guacamole.AudioChannel = function() {
+
+    /**
+     * Reference to this AudioChannel.
+     * @private
+     */
+    var channel = this;
+
+    /**
+     * When the next packet should play.
+     * @private
+     */
+    var next_packet_time = 0;
+
+    /**
+     * Queues up the given data for playing by this channel once all previously
+     * queued data has been played. If no data has been queued, the data will
+     * play immediately.
+     * 
+     * @param {String} mimetype The mimetype of the data provided.
+     * @param {Number} duration The duration of the data provided, in
+     *                          milliseconds.
+     * @param {Blob} data The blob data to play.
+     */
+    this.play = function(mimetype, duration, data) {
+
+        var packet =
+            new Guacamole.AudioChannel.Packet(mimetype, data);
+
+        var now = Guacamole.AudioChannel.getTimestamp();
+
+        // If underflow is detected, reschedule new packets relative to now.
+        if (next_packet_time < now)
+            next_packet_time = now;
+
+        // Schedule next packet
+        packet.play(next_packet_time);
+        next_packet_time += duration;
+
+    };
+
+};
+
+// Define context if available
+if (window.webkitAudioContext) {
+    Guacamole.AudioChannel.context = new webkitAudioContext();
+}
+
+/**
+ * Returns a base timestamp which can be used for scheduling future audio
+ * playback. Scheduling playback for the value returned by this function plus
+ * N will cause the associated audio to be played back N milliseconds after
+ * the function is called.
+ *
+ * @return {Number} An arbitrary channel-relative timestamp, in milliseconds.
+ */
+Guacamole.AudioChannel.getTimestamp = function() {
+
+    // If we have an audio context, use its timestamp
+    if (Guacamole.AudioChannel.context)
+        return Guacamole.AudioChannel.context.currentTime * 1000;
+
+    // If we have high-resolution timers, use those
+    if (window.performance) {
+
+        if (window.performance.now)
+            return window.performance.now();
+
+        if (window.performance.webkitNow)
+            return window.performance.webkitNow();
+        
+    }
+
+    // Fallback to millisecond-resolution system time
+    return new Date().getTime();
+
+};
+
+/**
+ * Abstract representation of an audio packet.
+ * 
+ * @constructor
+ * 
+ * @param {String} mimetype The mimetype of the data contained by this packet.
+ * @param {Blob} data The blob of sound data contained by this packet.
+ */
+Guacamole.AudioChannel.Packet = function(mimetype, data) {
+
+    /**
+     * Schedules this packet for playback at the given time.
+     *
+     * @function
+     * @param {Number} when The time this packet should be played, in
+     *                      milliseconds.
+     */
+    this.play = undefined; // Defined conditionally depending on support
+
+    // If audio API available, use it.
+    if (Guacamole.AudioChannel.context) {
+
+        var readyBuffer = null;
+
+        // By default, when decoding finishes, store buffer for future
+        // playback
+        var handleReady = function(buffer) {
+            readyBuffer = buffer;
+        };
+
+        // Read data and start decoding
+        var reader = new FileReader();
+        reader.onload = function() {
+            Guacamole.AudioChannel.context.decodeAudioData(
+                reader.result,
+                function(buffer) { handleReady(buffer); }
+            );
+        };
+        reader.readAsArrayBuffer(data);
+
+        // Set up buffer source
+        var source = Guacamole.AudioChannel.context.createBufferSource();
+        source.connect(Guacamole.AudioChannel.context.destination);
+
+        var play_when;
+
+        function playDelayed(buffer) {
+            source.buffer = buffer;
+            source.noteOn(play_when / 1000);
+        }
+
+        /** @ignore */
+        this.play = function(when) {
+            
+            play_when = when;
+            
+            // If buffer available, play it NOW
+            if (readyBuffer)
+                playDelayed(readyBuffer);
+
+            // Otherwise, play when decoded
+            else
+                handleReady = playDelayed;
+
+        };
+
+    }
+
+    else {
+
+        var play_on_load = false;
+
+        // Create audio element to house and play the data
+        var audio = new Audio();
+
+        // Read data and start decoding
+        var reader = new FileReader();
+        reader.onload = function() {
+
+            var binary = "";
+            var bytes = new Uint8Array(reader.result);
+
+            // Produce binary string from bytes in buffer
+            for (var i=0; i<bytes.byteLength; i++)
+                binary += String.fromCharCode(bytes[i]);
+
+            // Convert to data URI 
+            audio.src = "data:" + mimetype + ";base64," + window.btoa(binary);
+
+            // Play if play was attempted but packet wasn't loaded yet
+            if (play_on_load)
+                audio.play();
+
+        };
+        reader.readAsArrayBuffer(data);
+   
+        function play() {
+
+            // If audio data is ready, play now
+            if (audio.src)
+                audio.play();
+
+            // Otherwise, play when loaded
+            else
+                play_on_load = true;
+
+        }
+        
+        /** @ignore */
+        this.play = function(when) {
+            
+            // Calculate time until play
+            var now = Guacamole.AudioChannel.getTimestamp();
+            var delay = when - now;
+            
+            // Play now if too late
+            if (delay < 0)
+                play();
+
+            // Otherwise, schedule later playback
+            else
+                window.setTimeout(play, delay);
+
+        };
+
+    }
+
+};