[Files.app] Initial implementation of new audio player

chrome/browser/resources/file_manager/audio_player/js/audio_player.js

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+'use strict';
+
+/**
+ * @param {HTMLElement} container Container element.
+ * @constructor
+ */
+function AudioPlayer(container) {
+  this.container_ = container;
+  this.volumeManager_ = new VolumeManagerWrapper(
+      VolumeManagerWrapper.DriveEnabledStatus.DRIVE_ENABLED);
+  this.metadataCache_ = MetadataCache.createFull(this.volumeManager_);
+
+  this.currentTrackIndex_ = -1;
+  this.playlistGeneration_ = 0;
+
+  this.player_ = document.querySelector('audio-player');
+  this.trackListItems_ = [];
+  this.player_.tracks = this.trackListItems_;
+  Platform.performMicrotaskCheckpoint();
+
+  this.errorString_ = '';
+  this.offlineString_ = '';
+  chrome.fileBrowserPrivate.getStrings(function(strings) {
+    container.ownerDocument.title = strings['AUDIO_PLAYER_TITLE'];
+    this.errorString_ = strings['AUDIO_ERROR'];
+    this.offlineString_ = strings['AUDIO_OFFLINE'];
+    AudioPlayer.TrackInfo.DEFAULT_ARTIST =
+        strings['AUDIO_PLAYER_DEFAULT_ARTIST'];
+  }.bind(this));
+
+  this.volumeManager_.addEventListener('externally-unmounted',
+      this.onExternallyUnmounted_.bind(this));
+
+  window.addEventListener('resize', this.onResize_.bind(this));
+
+  // Show the window after DOM is processed.
+  var currentWindow = chrome.app.window.current();
+  if (currentWindow)
+    setTimeout(currentWindow.show.bind(currentWindow), 0);
+}
+
+/**
+ * Initial load method (static).
+ */
+AudioPlayer.load = function() {
+  document.ondragstart = function(e) { e.preventDefault() };
+
+  // TODO(mtomasz): Consider providing an exact size icon, instead of relying
+  // on downsampling by ash.
+  chrome.app.window.current().setIcon(
+      'audio_player/icons/audio-player-64.png');
+  AudioPlayer.instance =
+      new AudioPlayer(document.querySelector('.audio-player'));
+
+  reload();
+};
+
+/**
+ * Unloads the player.
+ */
+function unload() {
+  if (AudioPlayer.instance)
+    AudioPlayer.instance.onUnload();
+}
+
+/**
+ * Reloads the player.
+ */
+function reload() {
+  if (window.appState) {
+    util.saveAppState();
+    AudioPlayer.instance.load(window.appState);
+    return;
+  }
+}
+
+/**
+ * Loads a new playlist.
+ * @param {Playlist} playlist Playlist object passed via mediaPlayerPrivate.
+ */
+AudioPlayer.prototype.load = function(playlist) {
+  this.playlistGeneration_++;
+  this.currentTrackIndex_ = -1;
+
+  // Save the app state, in case of restart.
+  window.appState = playlist;
+  util.saveAppState();
+
+  // Resolving entries has to be done after the volume manager is initialized.
+  this.volumeManager_.ensureInitialized(function() {
+    util.URLsToEntries(playlist.items, function(entries) {
+      this.entries_ = entries;
+
+      var position = playlist.position || 0;
+      var time = playlist.time || 0;
+
+      this.syncHeight_();
+
+      if (this.entries_.length == 0)
+        return;
+
+      this.trackListItems_.splice(0);
+
+      for (var i = 0; i != this.entries_.length; i++) {
+        var entry = this.entries_[i];
+        var onClick = this.select_.bind(this, i, false /* no restore */);
+        this.trackListItems_.push(new AudioPlayer.TrackInfo(entry, onClick));
+      }
+
+      this.select_(position, !!time);
+
+      // Load the selected track metadata first, then load the rest.
+      this.loadMetadata_(position);
+      for (i = 0; i != this.entries_.length; i++) {
+        if (i != position)
+          this.loadMetadata_(i);
+      }
+    }.bind(this));
+  }.bind(this));
+};
+
+/**
+ * Loads metadata for a track.
+ * @param {number} track Track number.
+ * @private
+ */
+AudioPlayer.prototype.loadMetadata_ = function(track) {
+  this.fetchMetadata_(
+      this.entries_[track], this.displayMetadata_.bind(this, track));
+};
+
+/**
+ * Displays track's metadata.
+ * @param {number} track Track number.
+ * @param {Object} metadata Metadata object.
+ * @param {string=} opt_error Error message.
+ * @private
+ */
+AudioPlayer.prototype.displayMetadata_ = function(track, metadata, opt_error) {
+  this.trackListItems_[track].setMetadata(metadata, opt_error);
+};
+
+/**
+ * Closes audio player when a volume containing the selected item is unmounted.
+ * @param {Event} event The unmount event.
+ * @private
+ */
+AudioPlayer.prototype.onExternallyUnmounted_ = function(event) {
+  if (!this.selectedItemFilesystemPath_)
+    return;
+  if (this.selectedItemFilesystemPath_.indexOf(event.mountPath) == 0)
+    close();
+};
+
+/**
+ * Called on window is being unloaded.
+ */
+AudioPlayer.prototype.onUnload = function() {
+  if (this.player_)
+    this.player_.onPageUnload();
+
+  if (this.volumeManager_)
+    this.volumeManager_.dispose();
+};
+
+/**
+ * Selects a new track to play.
+ * @param {number} newTrack New track number.
+ * @param {boolean=} opt_restoreState True if restoring the play state from URL.
+ * @private
+ */
+AudioPlayer.prototype.select_ = function(newTrack, opt_restoreState) {
+  if (this.currentTrackIndex_ == newTrack) return;
+
+  this.currentTrackIndex_ = newTrack;
+  this.player_.currentTrackIndex = this.currentTrackIndex_;
+
+  if (window.appState) {
+    window.appState.position = this.currentTrackIndex_;
+    window.appState.time = 0;
+    util.saveAppState();
+  } else {
+    util.platform.setPreference(AudioPlayer.TRACK_KEY, this.currentTrackIndex_);
+  }
+
+  var entry = this.entries_[this.currentTrackIndex_];
+
+  this.fetchMetadata_(entry, function(metadata) {
+    if (this.currentTrackIndex_ != newTrack)
+      return;
+
+    // Resolve real filesystem path of the current audio file.
+    this.selectedItemFilesystemPath_ = null;
+    this.selectedItemFilesystemPath_ = entry.fullPath;
+  }.bind(this));
+};
+
+/**
+ * @param {FileEntry} entry Track file entry.
+ * @param {function(object)} callback Callback.
+ * @private
+ */
+AudioPlayer.prototype.fetchMetadata_ = function(entry, callback) {
+  this.metadataCache_.get(entry, 'thumbnail|media|streaming',
+      function(generation, metadata) {
+        // Do nothing if another load happened since the metadata request.
+        if (this.playlistGeneration_ == generation)
+          callback(metadata);
+      }.bind(this, this.playlistGeneration_));
+};
+
+/**
+ * @return {boolean} True if the player is be displayed in compact mode.
+ * @private
+ */
+AudioPlayer.prototype.isExpanded_ = function() {
+  return this.player_.isExpanded();
+};
+
+/**
+ * Media error handler.
+ * @private
+ */
+AudioPlayer.prototype.onError_ = function() {
+  var track = this.currentTrackIndex_;
+
+  this.invalidTracks_[track] = true;
+
+  this.fetchMetadata_(
+      this.entries_[track],
+      function(metadata) {
+        var error = (!navigator.onLine && metadata.streaming) ?
+            this.offlineString_ : this.errorString_;
+        this.displayMetadata_(track, metadata, error);
+        this.scheduleAutoAdvance_();
+      }.bind(this));
+};
+
+/**
+ * Expands/collapses button click handler. Toggles the mode and updates the
+ * height of the window.
+ *
+ * @private
+ */
+AudioPlayer.prototype.onExpandCollapse_ = function() {
+  if (this.isExpanded_) {
+    this.player_.expand(false);
+  } else {
+    this.player_.expand(true);
+  }
+  this.syncHeight_();
+};
+
+/**
+ * Toggles the expanded mode when resizing.
+ *
+ * @param {Event} event Resize event.
+ * @private
+ */
+AudioPlayer.prototype.onResize_ = function(event) {
+  if (!this.isExpanded_ &&
+      window.innerHeight >= AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
+    this.isExpanded_ = true;
+    this.player_.expand(true);
+  } else if (this.isExpanded_ &&
+             window.innerHeight < AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
+    this.isExpanded_ = false;
+    this.player_.expand(false);
+  }
+};
+
+/* Keep the below constants in sync with the CSS. */
+
+/**
+ * Window header size in pixels.
+ * @type {number}
+ * @const
+ */
+AudioPlayer.HEADER_HEIGHT = 28;
+
+/**
+ * Track height in pixels.
+ * @type {number}
+ * @const
+ */
+AudioPlayer.TRACK_HEIGHT = 44;
+
+/**
+ * Controls bar height in pixels.
+ * @type {number}
+ * @const
+ */
+AudioPlayer.CONTROLS_HEIGHT = 72;
+
+/**
+ * Default number of items in the expanded mode.
+ * @type {number}
+ * @const
+ */
+AudioPlayer.DEFAULT_EXPANDED_ITEMS = 5;
+
+/**
+ * Minimum size of the window in the expanded mode in pixels.
+ * @type {number}
+ * @const
+ */
+AudioPlayer.EXPANDED_MODE_MIN_HEIGHT = AudioPlayer.CONTROLS_HEIGHT +
+                                       AudioPlayer.TRACK_HEIGHT * 2;
+
+/**
+ * Sets the correct player window height.
+ */
+AudioPlayer.prototype.syncExpanded = function() {
+  if (this.isExpanded_ == this.player_.isExpanded())
+    return;
+
+  if (this.isExpanded_ && !this.player_.isExpanded())
+    this.lastExpandedHeight_ = window.innerHeight;
+
+  this.isExpanded_ = this.player_.isExpanded();
+  this.syncHeight_();
+};
+
+/**
+ * @private
+ */
+AudioPlayer.prototype.syncHeight_ = function() {
+  var targetHeight;
+
+  if (this.isExpanded_) {
+    // Expanded.
+    if (!this.lastExpandedHeight_ ||
+        this.lastExpandedHeight_ < AudioPlayer.EXPANDED_MODE_MIN_HEIGHT) {
+      var expandedListHeight =
+        Math.min(this.entries_.length, AudioPlayer.DEFAULT_EXPANDED_ITEMS) *
+                                       AudioPlayer.TRACK_HEIGHT;
+      targetHeight = AudioPlayer.CONTROLS_HEIGHT + expandedListHeight;
+    } else {
+      targetHeight = this.lastExpandedHeight_;
+    }
+  } else {
+    // Not expaned.
+    targetHeight = AudioPlayer.CONTROLS_HEIGHT + AudioPlayer.TRACK_HEIGHT;
+  }
+
+  window.resizeTo(window.innerWidth, targetHeight + AudioPlayer.HEADER_HEIGHT);
+};
+
+/**
+ * Create a TrackInfo object encapsulating the information about one track.
+ *
+ * @param {fileEntry} entry FileEntry to be retrieved the track info from.
+ * @param {function} onClick Click handler.
+ * @constructor
+ */
+AudioPlayer.TrackInfo = function(entry, onClick) {
+  this.url = entry.toURL();
+  this.title = entry.name;
+  this.artist = this.getDefaultArtist();
+
+  // TODO(yoshiki): implement artwork.
+  this.artwork = null;
+  this.active = false;
+};
+
+/**
+ * @return {HTMLDivElement} The wrapper element for the track.
+ */
+AudioPlayer.TrackInfo.prototype.getBox = function() { return this.box_ };
+
+/**
+ * @return {string} Default track title (file name extracted from the url).
+ */
+AudioPlayer.TrackInfo.prototype.getDefaultTitle = function() {
+  var title = this.url.split('/').pop();
+  var dotIndex = title.lastIndexOf('.');
+  if (dotIndex >= 0) title = title.substr(0, dotIndex);
+  title = decodeURIComponent(title);
+  return title;
+};
+
+/**
+ * TODO(kaznacheev): Localize.
+ */
+AudioPlayer.TrackInfo.DEFAULT_ARTIST = 'Unknown Artist';
+
+/**
+ * @return {string} 'Unknown artist' string.
+ */
+AudioPlayer.TrackInfo.prototype.getDefaultArtist = function() {
+  return AudioPlayer.TrackInfo.DEFAULT_ARTIST;
+};
+
+/**
+ * @param {Object} metadata The metadata object.
+ * @param {string} error Error string.
+ */
+AudioPlayer.TrackInfo.prototype.setMetadata = function(
+    metadata, error) {
+  if (error) {
+    // TODO(yoshiki): Handle error in better way.
+    this.title = entry.name;
+    this.artist = this.getDefaultArtist();
+  } else if (metadata.thumbnail && metadata.thumbnail.url) {
+    // TODO(yoshiki): implement artwork.
+  }
+  this.title = (metadata.media && metadata.media.title) ||
+      this.getDefaultTitle();
+  this.artist = error ||
+      (metadata.media && metadata.media.artist) || this.getDefaultArtist();
+};
+
+// Starts loading the audio player.
+window.addEventListener('WebComponentsReady', function(e) {
+  AudioPlayer.load();
+});