import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

addon-sdk/source/lib/sdk/keyboard/hotkeys.js

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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+module.metadata = {
+  "stability": "unstable"
+};
+
+const { observer: keyboardObserver } = require("./observer");
+const { getKeyForCode, normalize, isFunctionKey,
+        MODIFIERS } = require("./utils");
+
+/**
+ * Register a global `hotkey` that executes `listener` when the key combination
+ * in `hotkey` is pressed. If more then one `listener` is registered on the same
+ * key combination only last one will be executed.
+ *
+ * @param {string} hotkey
+ *    Key combination in the format of 'modifier key'.
+ *
+ * Examples:
+ *
+ *     "accel s"
+ *     "meta shift i"
+ *     "control alt d"
+ *
+ * Modifier keynames:
+ *
+ *  - **shift**: The Shift key.
+ *  - **alt**: The Alt key. On the Macintosh, this is the Option key. On
+ *    Macintosh this can only be used in conjunction with another modifier,
+ *    since `Alt+Letter` combinations are reserved for entering special
+ *    characters in text.
+ *  - **meta**: The Meta key. On the Macintosh, this is the Command key.
+ *  - **control**: The Control key.
+ *  - **accel**: The key used for keyboard shortcuts on the user's platform,
+ *    which is Control on Windows and Linux, and Command on Mac. Usually, this
+ *    would be the value you would use.
+ *
+ * @param {function} listener
+ *    Function to execute when the `hotkey` is executed.
+ */
+exports.register = function register(hotkey, listener) {
+  hotkey = normalize(hotkey);
+  hotkeys[hotkey] = listener;
+};
+
+/**
+ * Unregister a global `hotkey`. If passed `listener` is not the one registered
+ * for the given `hotkey`, the call to this function will be ignored.
+ *
+ * @param {string} hotkey
+ *    Key combination in the format of 'modifier key'.
+ * @param {function} listener
+ *    Function that will be invoked when the `hotkey` is pressed.
+ */
+exports.unregister = function unregister(hotkey, listener) {
+  hotkey = normalize(hotkey);
+  if (hotkeys[hotkey] === listener)
+    delete hotkeys[hotkey];
+};
+
+/**
+ * Map of hotkeys and associated functions.
+ */
+const hotkeys = exports.hotkeys = {};
+
+keyboardObserver.on("keydown", function onKeypress(event, window) {
+  let key, modifiers = [];
+  let isChar = "isChar" in event && event.isChar;
+  let which = "which" in event ? event.which : null;
+  let keyCode = "keyCode" in event ? event.keyCode : null;
+
+  if ("shiftKey" in event && event.shiftKey)
+    modifiers.push("shift");
+  if ("altKey" in event && event.altKey)
+    modifiers.push("alt");
+  if ("ctrlKey" in event && event.ctrlKey)
+    modifiers.push("control");
+  if ("metaKey" in event && event.metaKey)
+    modifiers.push("meta");
+
+  // If it's not a printable character then we fall back to a human readable
+  // equivalent of one of the following constants.
+  // http://dxr.mozilla.org/mozilla-central/source/dom/interfaces/events/nsIDOMKeyEvent.idl
+  key = getKeyForCode(keyCode);
+
+  // If only non-function (f1 - f24) key or only modifiers are pressed we don't
+  // have a valid combination so we return immediately (Also, sometimes
+  // `keyCode` may be one for the modifier which means we do not have a
+  // modifier).
+  if (!key || (!isFunctionKey(key) && !modifiers.length) || key in MODIFIERS)
+    return;
+
+  let combination = normalize({ key: key, modifiers: modifiers });
+  let hotkey = hotkeys[combination];
+
+  if (hotkey) {
+    try {
+      hotkey();
+    } catch (exception) {
+      console.exception(exception);
+    } finally {
+      // Work around bug 582052 by preventing the (nonexistent) default action.
+      event.preventDefault();
+    }
+  }
+});