Refactor: Extract a KeyboardHandler and CommandHandler from Background

chrome/browser/resources/chromeos/chromevox/cvox2/background/keyboard_handler.js

+// Copyright 2016 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.
+
+/**
+ * @fileoverview ChromeVox keyboard handler.
+ */
+
+goog.provide('BackgroundKeyboardHandler');
+
+goog.require('cvox.ChromeVoxKbHandler');
+
+/** @constructor */
+BackgroundKeyboardHandler = function() {
+  // Classic keymap.
+  cvox.ChromeVoxKbHandler.handlerKeyMap = cvox.KeyMap.fromDefaults();
+
+  /** @type {number} @private */
+  this.passThroughKeyUpCount_ = 0;
+
+  document.addEventListener('keydown', this.onKeyDown.bind(this), false);
+  document.addEventListener('keyup', this.onKeyUp.bind(this), false);
+};
+
+BackgroundKeyboardHandler.prototype = {
+  /**
+   * Handles key down events.
+   * @param {Event} evt The key down event to process.
+   * @return {boolean} True if the default action should be performed.
+   */
+  onKeyDown: function(evt) {
+    evt.stickyMode = cvox.ChromeVox.isStickyModeOn() && cvox.ChromeVox.isActive;
+    if (cvox.ChromeVox.passThroughMode)
+      return false;
+
+    if (ChromeVoxState.instance.mode != ChromeVoxMode.CLASSIC &&
+        !cvox.ChromeVoxKbHandler.basicKeyDownActionsListener(evt)) {
+      evt.preventDefault();
+      evt.stopPropagation();
+    }
+    Output.flushNextSpeechUtterance();
+    return false;
+  },
+
+  /**
+   * Handles key up events.
+   * @param {Event} evt The key down event to process.
+   * @return {boolean} True if the default action should be performed.
+   */
+  onKeyUp: function(evt) {
+    // Reset pass through mode once a keyup (not involving the pass through key)
+    // is seen. The pass through command involves three keys.
+    if (cvox.ChromeVox.passThroughMode) {
+      if (this.passThroughKeyUpCount_ >= 3) {
+        cvox.ChromeVox.passThroughMode = false;
+        this.passThroughKeyUpCount_ = 0;
+      } else {
+        this.passThroughKeyUpCount_++;
+      }
+    }
+    return false;
+  },
+
+  /**
+   * React to mode changes.
+   * @param {ChromeVoxMode} newMode
+   * @param {ChromeVoxMode?} oldMode
+   */
+  onModeChanged: function(newMode, oldMode) {
+    if (newMode == ChromeVoxMode.CLASSIC) {
+      chrome.accessibilityPrivate.setKeyboardListener(false, false);
+    } else {
+      chrome.accessibilityPrivate.setKeyboardListener(
+          true, cvox.ChromeVox.isStickyPrefOn);
+    }
+
+    // Switching out of next, force next, or uninitialized (on startup).
+    if (newMode === ChromeVoxMode.NEXT ||
+        newMode === ChromeVoxMode.FORCE_NEXT) {
+      window['prefs'].switchToKeyMap('keymap_next');
+    } else {
+      // Moving from next to classic/compat should be the only case where
+      // keymaps get reset. Note the classic <-> compat switches should preserve
+      // keymaps especially if a user selected a different one.
+      if (oldMode &&
+          oldMode != ChromeVoxMode.CLASSIC &&
+          oldMode != ChromeVoxMode.COMPAT) {
+        // The user's configured key map gets wiped here; this is consistent
+        // with previous behavior when switching keymaps.
+        window['prefs'].switchToKeyMap('keymap_next');
+      }
+    }
+  }
+};