michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "unstable"
michael@0: };
michael@0: 
michael@0: const { observer: keyboardObserver } = require("./observer");
michael@0: const { getKeyForCode, normalize, isFunctionKey,
michael@0:         MODIFIERS } = require("./utils");
michael@0: 
michael@0: /**
michael@0:  * Register a global `hotkey` that executes `listener` when the key combination
michael@0:  * in `hotkey` is pressed. If more then one `listener` is registered on the same
michael@0:  * key combination only last one will be executed.
michael@0:  *
michael@0:  * @param {string} hotkey
michael@0:  *    Key combination in the format of 'modifier key'.
michael@0:  *
michael@0:  * Examples:
michael@0:  *
michael@0:  *     "accel s"
michael@0:  *     "meta shift i"
michael@0:  *     "control alt d"
michael@0:  *
michael@0:  * Modifier keynames:
michael@0:  *
michael@0:  *  - **shift**: The Shift key.
michael@0:  *  - **alt**: The Alt key. On the Macintosh, this is the Option key. On
michael@0:  *    Macintosh this can only be used in conjunction with another modifier,
michael@0:  *    since `Alt+Letter` combinations are reserved for entering special
michael@0:  *    characters in text.
michael@0:  *  - **meta**: The Meta key. On the Macintosh, this is the Command key.
michael@0:  *  - **control**: The Control key.
michael@0:  *  - **accel**: The key used for keyboard shortcuts on the user's platform,
michael@0:  *    which is Control on Windows and Linux, and Command on Mac. Usually, this
michael@0:  *    would be the value you would use.
michael@0:  *
michael@0:  * @param {function} listener
michael@0:  *    Function to execute when the `hotkey` is executed.
michael@0:  */
michael@0: exports.register = function register(hotkey, listener) {
michael@0:   hotkey = normalize(hotkey);
michael@0:   hotkeys[hotkey] = listener;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Unregister a global `hotkey`. If passed `listener` is not the one registered
michael@0:  * for the given `hotkey`, the call to this function will be ignored.
michael@0:  *
michael@0:  * @param {string} hotkey
michael@0:  *    Key combination in the format of 'modifier key'.
michael@0:  * @param {function} listener
michael@0:  *    Function that will be invoked when the `hotkey` is pressed.
michael@0:  */
michael@0: exports.unregister = function unregister(hotkey, listener) {
michael@0:   hotkey = normalize(hotkey);
michael@0:   if (hotkeys[hotkey] === listener)
michael@0:     delete hotkeys[hotkey];
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Map of hotkeys and associated functions.
michael@0:  */
michael@0: const hotkeys = exports.hotkeys = {};
michael@0: 
michael@0: keyboardObserver.on("keydown", function onKeypress(event, window) {
michael@0:   let key, modifiers = [];
michael@0:   let isChar = "isChar" in event && event.isChar;
michael@0:   let which = "which" in event ? event.which : null;
michael@0:   let keyCode = "keyCode" in event ? event.keyCode : null;
michael@0: 
michael@0:   if ("shiftKey" in event && event.shiftKey)
michael@0:     modifiers.push("shift");
michael@0:   if ("altKey" in event && event.altKey)
michael@0:     modifiers.push("alt");
michael@0:   if ("ctrlKey" in event && event.ctrlKey)
michael@0:     modifiers.push("control");
michael@0:   if ("metaKey" in event && event.metaKey)
michael@0:     modifiers.push("meta");
michael@0: 
michael@0:   // If it's not a printable character then we fall back to a human readable
michael@0:   // equivalent of one of the following constants.
michael@0:   // http://mxr.mozilla.org/mozilla-central/source/dom/interfaces/events/nsIDOMKeyEvent.idl
michael@0:   key = getKeyForCode(keyCode);
michael@0: 
michael@0:   // If only non-function (f1 - f24) key or only modifiers are pressed we don't
michael@0:   // have a valid combination so we return immediately (Also, sometimes
michael@0:   // `keyCode` may be one for the modifier which means we do not have a
michael@0:   // modifier).
michael@0:   if (!key || (!isFunctionKey(key) && !modifiers.length) || key in MODIFIERS)
michael@0:     return;
michael@0: 
michael@0:   let combination = normalize({ key: key, modifiers: modifiers });
michael@0:   let hotkey = hotkeys[combination];
michael@0: 
michael@0:   if (hotkey) {
michael@0:     try {
michael@0:       hotkey();
michael@0:     } catch (exception) {
michael@0:       console.exception(exception);
michael@0:     } finally {
michael@0:       // Work around bug 582052 by preventing the (nonexistent) default action.
michael@0:       event.preventDefault();
michael@0:     }
michael@0:   }
michael@0: });