remoting/webapp/crd/js/video_frame_recorder.js

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /**
   6  * @fileoverview
   7  * Class implement the video frame recorder extension client.
   8  */
   9
  10 'use strict';
  11
  12 /** @suppress {duplicate} */
  13 var remoting = remoting || {};
  14
  15 /**
  16  * @constructor
  17  * @implements {remoting.ProtocolExtension}
  18  */
  19 remoting.VideoFrameRecorder = function() {
  20   /** @private {?function(string,string)} */
  21   this.sendMessageToHostCallback_ = null;
  22
  23   this.fileWriter_ = null;
  24   this.isRecording_ = false;
  25 };
  26
  27 /** @private {string} */
  28 remoting.VideoFrameRecorder.EXTENSION_TYPE = 'video-recorder';
  29
  30 /** @return {Array<string>} */
  31 remoting.VideoFrameRecorder.prototype.getExtensionTypes = function() {
  32   return [remoting.VideoFrameRecorder.EXTENSION_TYPE];
  33 };
  34
  35 /**
  36  * @param {function(string,string)} sendMessageToHost Callback to send a message
  37  *     to the host.
  38  */
  39 remoting.VideoFrameRecorder.prototype.startExtension =
  40     function(sendMessageToHost) {
  41   this.sendMessageToHostCallback_ = sendMessageToHost;
  42 };
  43
  44 /**
  45  * @param {Object} data The data to send.
  46  * @private
  47  */
  48 remoting.VideoFrameRecorder.prototype.sendMessageToHost_ = function(data) {
  49   this.sendMessageToHostCallback_(remoting.VideoFrameRecorder.EXTENSION_TYPE,
  50                                   JSON.stringify(data));
  51 }
  52
  53 /**
  54  * Handles 'video-recorder' extension messages and returns true. Returns
  55  * false for all other message types.
  56  *
  57  * @param {string} type Type of extension message.
  58  * @param {Object} message The parsed extension message data.
  59  * @return {boolean}
  60  */
  61 remoting.VideoFrameRecorder.prototype.onExtensionMessage =
  62     function(type, message) {
  63   console.assert(type == remoting.VideoFrameRecorder.EXTENSION_TYPE,
  64                 'Unexpected extension message type: ' + type + '.');
  65
  66   var messageType = base.getStringAttr(message, 'type');
  67   var messageData = base.getStringAttr(message, 'data');
  68
  69   if (messageType == 'next-frame-reply') {
  70     if (!this.fileWriter_) {
  71       console.log("Received frame but have no writer");
  72       return true;
  73     }
  74     if (!messageData) {
  75       console.log("Finished receiving frames");
  76       this.fileWriter_ = null;
  77       return true;
  78     }
  79
  80     console.log("Received frame");
  81     var videoPacketString = window.atob(messageData);
  82
  83     console.log("Converted from Base64 - length:" + videoPacketString.length);
  84     var byteArrays = [];
  85
  86     for (var offset = 0; offset < videoPacketString.length; offset += 512) {
  87         var slice = videoPacketString.slice(offset, offset + 512);
  88         var byteNumbers = new Array(slice.length);
  89         for (var i = 0; i < slice.length; i++) {
  90             byteNumbers[i] = slice.charCodeAt(i);
  91         }
  92         var byteArray = new Uint8Array(byteNumbers);
  93         byteArrays.push(byteArray);
  94     }
  95
  96     console.log("Writing frame");
  97     videoPacketString = null;
  98     /**
  99      * @param {Array} parts
 100      * @return {Blob}
 101      */
 102     var makeBlob = function(parts) {
 103       return new Blob(parts);
 104     }
 105     var videoPacketBlob = makeBlob(byteArrays);
 106     byteArrays = null;
 107
 108     this.fileWriter_.write(videoPacketBlob);
 109
 110     return true;
 111   }
 112
 113   console.log("Unrecognized message: " + messageType);
 114   return true;
 115 }
 116
 117 /**
 118  * Starts or stops video recording.
 119  */
 120 remoting.VideoFrameRecorder.prototype.startStopRecording = function() {
 121   var data = {};
 122   if (this.isRecording_) {
 123     this.isRecording_ = false;
 124     data = { type: 'stop' }
 125
 126     chrome.fileSystem.chooseEntry(
 127         {type: 'saveFile', suggestedName: 'videoRecording.pb'},
 128         this.onFileChosen_.bind(this));
 129   } else {
 130     this.isRecording_ = true;
 131     data = { type: 'start' }
 132   }
 133   this.sendMessageToHost_(data);
 134 }
 135
 136 /**
 137  * Returns true if the session is currently being recorded.
 138  * @return {boolean}
 139  */
 140 remoting.VideoFrameRecorder.prototype.isRecording = function() {
 141   return this.isRecording_;
 142 }
 143
 144 /**
 145  * @param {Entry=} entry The single file entry if multiple files are not
 146  *     allowed.
 147  * @param {Array<!FileEntry>=} fileEntries List of file entries if multiple
 148  *     files are allowed.
 149  */
 150 remoting.VideoFrameRecorder.prototype.onFileChosen_ = function(
 151     entry, fileEntries) {
 152   if (!entry) {
 153     console.log("Cancelled save of video frames.");
 154   } else {
 155     chrome.fileSystem.getDisplayPath(entry, function(path) {
 156       console.log("Saving video frames to:" + path);
 157     });
 158     entry.createWriter(this.onFileWriter_.bind(this));
 159   }
 160 }
 161
 162 /** @param {FileWriter} fileWriter */
 163 remoting.VideoFrameRecorder.prototype.onFileWriter_ = function(fileWriter) {
 164   console.log("Obtained FileWriter for video frame write");
 165   fileWriter.onwriteend = this.onWriteComplete_.bind(this);
 166   this.fileWriter_ = fileWriter;
 167   this.fetchNextFrame_();
 168 }
 169
 170 remoting.VideoFrameRecorder.prototype.onWriteComplete_ = function(e) {
 171   console.log("Video frame write complete");
 172   this.fetchNextFrame_();
 173 }
 174
 175 remoting.VideoFrameRecorder.prototype.fetchNextFrame_ = function() {
 176   console.log("Request next video frame");
 177   var data = { type: 'next-frame' }
 178   this.sendMessageToHost_(data);
 179 }