polygerrit-ui/app/services/shortcuts/shortcuts-service.ts - gerrit - Git at Google

 /**
  * @license
  * Copyright (C) 2021 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 import {
   config,
   Shortcut,
   ShortcutHelpItem,
   ShortcutSection,
   SPECIAL_SHORTCUT,
 } from './shortcuts-config';
 import {disableShortcuts$} from '../user/user-model';
 import {IronKeyboardEvent, isIronKeyboardEvent} from '../../types/events';
 import {isElementTarget} from '../../utils/dom-util';
 import {ReportingService} from '../gr-reporting/gr-reporting';

 export type SectionView = Array<{binding: string[][]; text: string}>;

 /**
  * The interface for listener for shortcut events.
  */
 export type ShortcutListener = (
   viewMap?: Map<ShortcutSection, SectionView>
 ) => void;

 const COMBO_KEYS = ['g', 'v'];

 /**
  * Shortcuts service, holds all hosts, bindings and listeners.
  */
 export class ShortcutsService {
   /**
    * Keeps track of the components that are currently active such that we can
    * show a shortcut help dialog that only shows the shortcuts that are
    * currently relevant.
    */
   private readonly activeHosts = new Map<unknown, Map<string, string>>();

   /** Static map built in the constructor by iterating over the config. */
   private readonly bindings = new Map<Shortcut, string[]>();

   private readonly listeners = new Set<ShortcutListener>();

   /**
    * Maps keys (e.g. 'g') to the timestamp when they have last been pressed.
    * This enabled key combinations like 'g+o' where we can check whether 'g' was
    * pressed recently when 'o' is processed. Keys of this map must be items of
    * COMBO_KEYS. Values are Date timestamps in milliseconds.
    */
   private readonly keyLastPressed = new Map<string, number>();

   /** Keeps track of the corresponding user preference. */
   private shortcutsDisabled = false;

   constructor(readonly reporting?: ReportingService) {
     for (const section of config.keys()) {
       const items = config.get(section) ?? [];
       for (const item of items) {
         this.bindings.set(item.shortcut, item.bindings);
       }
     }
     disableShortcuts$.subscribe(x => (this.shortcutsDisabled = x));
     document.addEventListener('keydown', (e: KeyboardEvent) => {
       if (!COMBO_KEYS.includes(e.key)) return;
       if (this.shouldSuppress(e)) return;
       this.keyLastPressed.set(e.key, Date.now());
     });
   }

   public _testOnly_isEmpty() {
     return this.activeHosts.size === 0 && this.listeners.size === 0;
   }

   shouldSuppress(event: IronKeyboardEvent | KeyboardEvent) {
     if (this.shortcutsDisabled) return true;
     const e = isIronKeyboardEvent(event) ? event.detail.keyboardEvent : event;

     // Note that when you listen on document, then `e.currentTarget` will be the
     // document and `e.target` will be `<gr-app>` due to shadow dom, but by
     // using the composedPath() you can actually find the true origin of the
     // event.
     const rootTarget = e.composedPath()[0];
     if (!isElementTarget(rootTarget)) return false;
     const tagName = rootTarget.tagName;
     const type = rootTarget.getAttribute('type');

     if (
       // Suppress shortcuts on <input> and <textarea>, but not on
       // checkboxes, because we want to enable workflows like 'click
       // mark-reviewed and then press ] to go to the next file'.
       (tagName === 'INPUT' && type !== 'checkbox') ||
       tagName === 'TEXTAREA' ||
       // Suppress shortcuts if the key is 'enter'
       // and target is an anchor or button or paper-tab.
       (e.keyCode === 13 &&
         (tagName === 'A' || tagName === 'BUTTON' || tagName === 'PAPER-TAB'))
     ) {
       return true;
     }
     const path: EventTarget[] = e.composedPath() ?? [];
     for (const el of path) {
       if (!isElementTarget(el)) continue;
       if (el.tagName === 'GR-OVERLAY') return true;
     }
     // eg: {key: "k:keydown", ..., from: "gr-diff-view"}
     let key = `${e.key}:${e.type}`;
     // TODO(brohlfs): Re-enable reporting of g- and v-keys.
     // if (this._inGoKeyMode()) key = 'g+' + key;
     // if (this.inVKeyMode()) key = 'v+' + key;
     if (e.shiftKey) key = 'shift+' + key;
     if (e.ctrlKey) key = 'ctrl+' + key;
     if (e.metaKey) key = 'meta+' + key;
     if (e.altKey) key = 'alt+' + key;
     let from = 'unknown';
     if (isElementTarget(e.currentTarget)) {
       from = e.currentTarget.tagName;
     }
     this.reporting?.reportInteraction('shortcut-triggered', {key, from});
     return false;
   }

   createTitle(shortcutName: Shortcut, section: ShortcutSection) {
     const desc = this.getDescription(section, shortcutName);
     const shortcut = this.getShortcut(shortcutName);
     return desc && shortcut ? `${desc} (shortcut: ${shortcut})` : '';
   }

   getBindingsForShortcut(shortcut: Shortcut) {
     return this.bindings.get(shortcut);
   }

   attachHost(host: unknown, shortcuts: Map<string, string>) {
     this.activeHosts.set(host, shortcuts);
     this.notifyListeners();
   }

   detachHost(host: unknown) {
     if (!this.activeHosts.delete(host)) return false;
     this.notifyListeners();
     return true;
   }

   addListener(listener: ShortcutListener) {
     this.listeners.add(listener);
     listener(this.directoryView());
   }

   removeListener(listener: ShortcutListener) {
     return this.listeners.delete(listener);
   }

   getDescription(section: ShortcutSection, shortcutName: Shortcut) {
     const bindings = config.get(section);
     if (!bindings) return '';
     const binding = bindings.find(binding => binding.shortcut === shortcutName);
     return binding?.text ?? '';
   }

   getShortcut(shortcutName: Shortcut) {
     const bindings = this.bindings.get(shortcutName);
     if (!bindings) return '';
     return bindings
       .map(binding => this.describeBinding(binding).join('+'))
       .join(',');
   }

   activeShortcutsBySection() {
     const activeShortcuts = new Set<string>();
     this.activeHosts.forEach(shortcuts => {
       shortcuts.forEach((_, shortcut) => activeShortcuts.add(shortcut));
     });

     const activeShortcutsBySection = new Map<
       ShortcutSection,
       ShortcutHelpItem[]
     >();
     config.forEach((shortcutList, section) => {
       shortcutList.forEach(shortcutHelp => {
         if (activeShortcuts.has(shortcutHelp.shortcut)) {
           if (!activeShortcutsBySection.has(section)) {
             activeShortcutsBySection.set(section, []);
           }
           // From previous condition, the `get(section)`
           // should always return a valid result
           activeShortcutsBySection.get(section)!.push(shortcutHelp);
         }
       });
     });
     return activeShortcutsBySection;
   }

   directoryView() {
     const view = new Map<ShortcutSection, SectionView>();
     this.activeShortcutsBySection().forEach((shortcutHelps, section) => {
       const sectionView: SectionView = [];
       shortcutHelps.forEach(shortcutHelp => {
         const bindingDesc = this.describeBindings(shortcutHelp.shortcut);
         if (!bindingDesc) {
           return;
         }
         this.distributeBindingDesc(bindingDesc).forEach(bindingDesc => {
           sectionView.push({
             binding: bindingDesc,
             text: shortcutHelp.text,
           });
         });
       });
       view.set(section, sectionView);
     });
     return view;
   }

   distributeBindingDesc(bindingDesc: string[][]): string[][][] {
     if (
       bindingDesc.length === 1 ||
       this.comboSetDisplayWidth(bindingDesc) < 21
     ) {
       return [bindingDesc];
     }
     // Find the largest prefix of bindings that is under the
     // size threshold.
     const head = [bindingDesc[0]];
     for (let i = 1; i < bindingDesc.length; i++) {
       head.push(bindingDesc[i]);
       if (this.comboSetDisplayWidth(head) >= 21) {
         head.pop();
         return [head].concat(this.distributeBindingDesc(bindingDesc.slice(i)));
       }
     }
     return [];
   }

   comboSetDisplayWidth(bindingDesc: string[][]) {
     const bindingSizer = (binding: string[]) =>
       binding.reduce((acc, key) => acc + key.length, 0);
     // Width is the sum of strings + (n-1) * 2 to account for the word
     // "or" joining them.
     return (
       bindingDesc.reduce((acc, binding) => acc + bindingSizer(binding), 0) +
       2 * (bindingDesc.length - 1)
     );
   }

   describeBindings(shortcut: Shortcut): string[][] | null {
     const bindings = this.bindings.get(shortcut);
     if (!bindings) {
       return null;
     }
     if (bindings[0] === SPECIAL_SHORTCUT.GO_KEY) {
       return bindings
         .slice(1)
         .map(binding => this._describeKey(binding))
         .map(binding => ['g'].concat(binding));
     }
     if (bindings[0] === SPECIAL_SHORTCUT.V_KEY) {
       return bindings
         .slice(1)
         .map(binding => this._describeKey(binding))
         .map(binding => ['v'].concat(binding));
     }

     return bindings
       .filter(binding => binding !== SPECIAL_SHORTCUT.DOC_ONLY)
       .map(binding => this.describeBinding(binding));
   }

   _describeKey(key: string) {
     switch (key) {
       case 'shift':
         return 'Shift';
       case 'meta':
         return 'Meta';
       case 'ctrl':
         return 'Ctrl';
       case 'enter':
         return 'Enter';
       case 'up':
         return '\u2191'; // ↑
       case 'down':
         return '\u2193'; // ↓
       case 'left':
         return '\u2190'; // ←
       case 'right':
         return '\u2192'; // →
       default:
         return key;
     }
   }

   describeBinding(binding: string) {
     // single key bindings
     if (binding.length === 1) {
       return [binding];
     }
     return binding
       .split(':')[0]
       .split('+')
       .map(part => this._describeKey(part));
   }

   notifyListeners() {
     const view = this.directoryView();
     this.listeners.forEach(listener => listener(view));
   }
 }
	/**
	* @license
	* Copyright (C) 2021 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	import {
	config,
	Shortcut,
	ShortcutHelpItem,
	ShortcutSection,
	SPECIAL_SHORTCUT,
	} from './shortcuts-config';
	import {disableShortcuts$} from '../user/user-model';
	import {IronKeyboardEvent, isIronKeyboardEvent} from '../../types/events';
	import {isElementTarget} from '../../utils/dom-util';
	import {ReportingService} from '../gr-reporting/gr-reporting';

	export type SectionView = Array<{binding: string[][]; text: string}>;

	/**
	* The interface for listener for shortcut events.
	*/
	export type ShortcutListener = (
	viewMap?: Map<ShortcutSection, SectionView>
	) => void;

	const COMBO_KEYS = ['g', 'v'];

	/**
	* Shortcuts service, holds all hosts, bindings and listeners.
	*/
	export class ShortcutsService {
	/**
	* Keeps track of the components that are currently active such that we can
	* show a shortcut help dialog that only shows the shortcuts that are
	* currently relevant.
	*/
	private readonly activeHosts = new Map<unknown, Map<string, string>>();

	/** Static map built in the constructor by iterating over the config. */
	private readonly bindings = new Map<Shortcut, string[]>();

	private readonly listeners = new Set<ShortcutListener>();

	/**
	* Maps keys (e.g. 'g') to the timestamp when they have last been pressed.
	* This enabled key combinations like 'g+o' where we can check whether 'g' was
	* pressed recently when 'o' is processed. Keys of this map must be items of
	* COMBO_KEYS. Values are Date timestamps in milliseconds.
	*/
	private readonly keyLastPressed = new Map<string, number>();

	/** Keeps track of the corresponding user preference. */
	private shortcutsDisabled = false;

	constructor(readonly reporting?: ReportingService) {
	for (const section of config.keys()) {
	const items = config.get(section) ?? [];
	for (const item of items) {
	this.bindings.set(item.shortcut, item.bindings);
	}
	}
	disableShortcuts$.subscribe(x => (this.shortcutsDisabled = x));
	document.addEventListener('keydown', (e: KeyboardEvent) => {
	if (!COMBO_KEYS.includes(e.key)) return;
	if (this.shouldSuppress(e)) return;
	this.keyLastPressed.set(e.key, Date.now());
	});
	}

	public _testOnly_isEmpty() {
	return this.activeHosts.size === 0 && this.listeners.size === 0;
	}

	shouldSuppress(event: IronKeyboardEvent \| KeyboardEvent) {
	if (this.shortcutsDisabled) return true;
	const e = isIronKeyboardEvent(event) ? event.detail.keyboardEvent : event;

	// Note that when you listen on document, then `e.currentTarget` will be the
	// document and `e.target` will be `<gr-app>` due to shadow dom, but by
	// using the composedPath() you can actually find the true origin of the
	// event.
	const rootTarget = e.composedPath()[0];
	if (!isElementTarget(rootTarget)) return false;
	const tagName = rootTarget.tagName;
	const type = rootTarget.getAttribute('type');

	if (
	// Suppress shortcuts on <input> and <textarea>, but not on
	// checkboxes, because we want to enable workflows like 'click
	// mark-reviewed and then press ] to go to the next file'.
	(tagName === 'INPUT' && type !== 'checkbox') \|\|
	tagName === 'TEXTAREA' \|\|
	// Suppress shortcuts if the key is 'enter'
	// and target is an anchor or button or paper-tab.
	(e.keyCode === 13 &&
	(tagName === 'A' \|\| tagName === 'BUTTON' \|\| tagName === 'PAPER-TAB'))
	) {
	return true;
	}
	const path: EventTarget[] = e.composedPath() ?? [];
	for (const el of path) {
	if (!isElementTarget(el)) continue;
	if (el.tagName === 'GR-OVERLAY') return true;
	}
	// eg: {key: "k:keydown", ..., from: "gr-diff-view"}
	let key = `${e.key}:${e.type}`;
	// TODO(brohlfs): Re-enable reporting of g- and v-keys.
	// if (this._inGoKeyMode()) key = 'g+' + key;
	// if (this.inVKeyMode()) key = 'v+' + key;
	if (e.shiftKey) key = 'shift+' + key;
	if (e.ctrlKey) key = 'ctrl+' + key;
	if (e.metaKey) key = 'meta+' + key;
	if (e.altKey) key = 'alt+' + key;
	let from = 'unknown';
	if (isElementTarget(e.currentTarget)) {
	from = e.currentTarget.tagName;
	}
	this.reporting?.reportInteraction('shortcut-triggered', {key, from});
	return false;
	}

	createTitle(shortcutName: Shortcut, section: ShortcutSection) {
	const desc = this.getDescription(section, shortcutName);
	const shortcut = this.getShortcut(shortcutName);
	return desc && shortcut ? `${desc} (shortcut: ${shortcut})` : '';
	}

	getBindingsForShortcut(shortcut: Shortcut) {
	return this.bindings.get(shortcut);
	}

	attachHost(host: unknown, shortcuts: Map<string, string>) {
	this.activeHosts.set(host, shortcuts);
	this.notifyListeners();
	}

	detachHost(host: unknown) {
	if (!this.activeHosts.delete(host)) return false;
	this.notifyListeners();
	return true;
	}

	addListener(listener: ShortcutListener) {
	this.listeners.add(listener);
	listener(this.directoryView());
	}

	removeListener(listener: ShortcutListener) {
	return this.listeners.delete(listener);
	}

	getDescription(section: ShortcutSection, shortcutName: Shortcut) {
	const bindings = config.get(section);
	if (!bindings) return '';
	const binding = bindings.find(binding => binding.shortcut === shortcutName);
	return binding?.text ?? '';
	}

	getShortcut(shortcutName: Shortcut) {
	const bindings = this.bindings.get(shortcutName);
	if (!bindings) return '';
	return bindings
	.map(binding => this.describeBinding(binding).join('+'))
	.join(',');
	}

	activeShortcutsBySection() {
	const activeShortcuts = new Set<string>();
	this.activeHosts.forEach(shortcuts => {
	shortcuts.forEach((_, shortcut) => activeShortcuts.add(shortcut));
	});

	const activeShortcutsBySection = new Map<
	ShortcutSection,
	ShortcutHelpItem[]
	>();
	config.forEach((shortcutList, section) => {
	shortcutList.forEach(shortcutHelp => {
	if (activeShortcuts.has(shortcutHelp.shortcut)) {
	if (!activeShortcutsBySection.has(section)) {
	activeShortcutsBySection.set(section, []);
	}
	// From previous condition, the `get(section)`
	// should always return a valid result
	activeShortcutsBySection.get(section)!.push(shortcutHelp);
	}
	});
	});
	return activeShortcutsBySection;
	}

	directoryView() {
	const view = new Map<ShortcutSection, SectionView>();
	this.activeShortcutsBySection().forEach((shortcutHelps, section) => {
	const sectionView: SectionView = [];
	shortcutHelps.forEach(shortcutHelp => {
	const bindingDesc = this.describeBindings(shortcutHelp.shortcut);
	if (!bindingDesc) {
	return;
	}
	this.distributeBindingDesc(bindingDesc).forEach(bindingDesc => {
	sectionView.push({
	binding: bindingDesc,
	text: shortcutHelp.text,
	});
	});
	});
	view.set(section, sectionView);
	});
	return view;
	}

	distributeBindingDesc(bindingDesc: string[][]): string[][][] {
	if (
	bindingDesc.length === 1 \|\|
	this.comboSetDisplayWidth(bindingDesc) < 21
	) {
	return [bindingDesc];
	}
	// Find the largest prefix of bindings that is under the
	// size threshold.
	const head = [bindingDesc[0]];
	for (let i = 1; i < bindingDesc.length; i++) {
	head.push(bindingDesc[i]);
	if (this.comboSetDisplayWidth(head) >= 21) {
	head.pop();
	return [head].concat(this.distributeBindingDesc(bindingDesc.slice(i)));
	}
	}
	return [];
	}

	comboSetDisplayWidth(bindingDesc: string[][]) {
	const bindingSizer = (binding: string[]) =>
	binding.reduce((acc, key) => acc + key.length, 0);
	// Width is the sum of strings + (n-1) * 2 to account for the word
	// "or" joining them.
	return (
	bindingDesc.reduce((acc, binding) => acc + bindingSizer(binding), 0) +
	2 * (bindingDesc.length - 1)
	);
	}

	describeBindings(shortcut: Shortcut): string[][] \| null {
	const bindings = this.bindings.get(shortcut);
	if (!bindings) {
	return null;
	}
	if (bindings[0] === SPECIAL_SHORTCUT.GO_KEY) {
	return bindings
	.slice(1)
	.map(binding => this._describeKey(binding))
	.map(binding => ['g'].concat(binding));
	}
	if (bindings[0] === SPECIAL_SHORTCUT.V_KEY) {
	return bindings
	.slice(1)
	.map(binding => this._describeKey(binding))
	.map(binding => ['v'].concat(binding));
	}

	return bindings
	.filter(binding => binding !== SPECIAL_SHORTCUT.DOC_ONLY)
	.map(binding => this.describeBinding(binding));
	}

	_describeKey(key: string) {
	switch (key) {
	case 'shift':
	return 'Shift';
	case 'meta':
	return 'Meta';
	case 'ctrl':
	return 'Ctrl';
	case 'enter':
	return 'Enter';
	case 'up':
	return '\u2191'; // ↑
	case 'down':
	return '\u2193'; // ↓
	case 'left':
	return '\u2190'; // ←
	case 'right':
	return '\u2192'; // →
	default:
	return key;
	}
	}

	describeBinding(binding: string) {
	// single key bindings
	if (binding.length === 1) {
	return [binding];
	}
	return binding
	.split(':')[0]
	.split('+')
	.map(part => this._describeKey(part));
	}

	notifyListeners() {
	const view = this.directoryView();
	this.listeners.forEach(listener => listener(view));
	}
	}