/* * Copyright (C) 2021 Yomichan Authors * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. */ /* global * DocumentUtil */ /** * Class which handles hotkey events and actions. */ class HotkeyHandler extends EventDispatcher { /** * Creates a new instance of the class. */ constructor() { super(); this._actions = new Map(); this._hotkeys = new Map(); this._hotkeyRegistrations = new Map(); this._eventListeners = new EventListenerCollection(); this._isPrepared = false; this._hasEventListeners = false; } /** * Begins listening to key press events in order to detect hotkeys. */ prepare() { this._isPrepared = true; this._updateEventHandlers(); yomichan.crossFrame.registerHandlers([ ['hotkeyHandler.forwardHotkey', {async: false, handler: this._onMessageForwardHotkey.bind(this)}] ]); } /** * Registers a set of actions that this hotkey handler supports. * @param actions An array of `[name, handler]` entries, where `name` is a string and `handler` is a function. */ registerActions(actions) { for (const [name, handler] of actions) { this._actions.set(name, handler); } } /** * Registers a set of hotkeys for a given scope. * @param scope The scope that the hotkey definitions must be for in order to be activated. * @param hotkeys An array of hotkey definitions of the format `{action, key, modifiers, scopes, enabled}`. * * `action` - a string indicating which action to perform. * * `key` - a keyboard key code indicating which key needs to be pressed. * * `modifiers` - an array of keyboard modifiers which also need to be pressed. Supports: `'alt', 'ctrl', 'shift', 'meta'`. * * `scopes` - an array of scopes for which the hotkey is valid. If this array does not contain `this.scope`, the hotkey will not be registered. * * `enabled` - a boolean indicating whether the hotkey is currently enabled. */ registerHotkeys(scope, hotkeys) { let registrations = this._hotkeyRegistrations.get(scope); if (typeof registrations === 'undefined') { registrations = []; this._hotkeyRegistrations.set(scope, registrations); } registrations.push(...hotkeys); this._updateHotkeyRegistrations(); } /** * Removes all registered hotkeys for a given scope. */ clearHotkeys(scope) { const registrations = this._hotkeyRegistrations.get(scope); if (typeof registrations !== 'undefined') { registrations.length = 0; } this._updateHotkeyRegistrations(); } /** * Assigns a set of hotkeys for a given scope. This is an optimized shorthand for calling * `clearHotkeys`, then calling `registerHotkeys`. * @see registerHotkeys for argument information. */ setHotkeys(scope, hotkeys) { let registrations = this._hotkeyRegistrations.get(scope); if (typeof registrations === 'undefined') { registrations = []; this._hotkeyRegistrations.set(scope, registrations); } else { registrations.length = 0; } registrations.push(...hotkeys); this._updateHotkeyRegistrations(); } /** * Adds a single event listener to a specific event. * @param eventName The string representing the event's name. * @param callback The event listener callback to add. */ on(eventName, callback) { const result = super.on(eventName, callback); this._updateHasEventListeners(); this._updateEventHandlers(); return result; } /** * Removes a single event listener from a specific event. * @param eventName The string representing the event's name. * @param callback The event listener callback to add. * @returns `true` if the callback was removed, `false` otherwise. */ off(eventName, callback) { const result = super.off(eventName, callback); this._updateHasEventListeners(); this._updateEventHandlers(); return result; } /** * Attempts to simulate an action for a given combination of key and modifiers. * @param key A keyboard key code indicating which key needs to be pressed. * @param modifiers An array of keyboard modifiers which also need to be pressed. Supports: `'alt', 'ctrl', 'shift', 'meta'`. * @returns `true` if an action was performed, `false` otherwise. */ simulate(key, modifiers) { const hotkeyInfo = this._hotkeys.get(key); return ( typeof hotkeyInfo !== 'undefined' && this._invokeHandlers(modifiers, hotkeyInfo) ); } // Message handlers _onMessageForwardHotkey({key, modifiers}) { return this.simulate(key, modifiers); } // Private _onKeyDown(e) { const hotkeyInfo = this._hotkeys.get(e.code); if (typeof hotkeyInfo !== 'undefined') { const eventModifiers = DocumentUtil.getActiveModifiers(e); if (this._invokeHandlers(eventModifiers, hotkeyInfo, e.key)) { e.preventDefault(); return; } } this.trigger('keydownNonHotkey', e); } _invokeHandlers(modifiers, hotkeyInfo, key) { for (const {modifiers: handlerModifiers, action, argument} of hotkeyInfo.handlers) { if (!this._areSame(handlerModifiers, modifiers) || !this._isHotkeyPermitted(modifiers, key)) { continue; } const actionHandler = this._actions.get(action); if (typeof actionHandler !== 'undefined') { const result = actionHandler(argument); if (result !== false) { return true; } } } return false; } _areSame(set, array) { if (set.size !== array.length) { return false; } for (const value of array) { if (!set.has(value)) { return false; } } return true; } _updateHotkeyRegistrations() { if (this._hotkeys.size === 0 && this._hotkeyRegistrations.size === 0) { return; } this._hotkeys.clear(); for (const [scope, registrations] of this._hotkeyRegistrations.entries()) { for (const {action, argument, key, modifiers, scopes, enabled} of registrations) { if (!(enabled && key !== null && action !== '' && scopes.includes(scope))) { continue; } let hotkeyInfo = this._hotkeys.get(key); if (typeof hotkeyInfo === 'undefined') { hotkeyInfo = {handlers: []}; this._hotkeys.set(key, hotkeyInfo); } hotkeyInfo.handlers.push({modifiers: new Set(modifiers), action, argument}); } } this._updateEventHandlers(); } _updateHasEventListeners() { this._hasEventListeners = this.hasListeners('keydownNonHotkey'); } _updateEventHandlers() { if (this._isPrepared && (this._hotkeys.size > 0 || this._hasEventListeners)) { if (this._eventListeners.size !== 0) { return; } this._eventListeners.addEventListener(document, 'keydown', this._onKeyDown.bind(this), false); } else { this._eventListeners.removeAllEventListeners(); } } _isHotkeyPermitted(modifiers, key) { return !( (modifiers.length === 0 || (modifiers.length === 1 && modifiers[0] === 'shift')) && DocumentUtil.isInputElementFocused() && this._isKeyCharacterInput(key) ); } _isKeyCharacterInput(key) { return key.length === 1; } }