view.js 22 KB

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  1. /**
  2. * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md.
  4. */
  5. /**
  6. * @module engine/view/view
  7. */
  8. import Document from './document';
  9. import DowncastWriter from './downcastwriter';
  10. import Renderer from './renderer';
  11. import DomConverter from './domconverter';
  12. import Position from './position';
  13. import Range from './range';
  14. import Selection from './selection';
  15. import MutationObserver from './observer/mutationobserver';
  16. import KeyObserver from './observer/keyobserver';
  17. import FakeSelectionObserver from './observer/fakeselectionobserver';
  18. import SelectionObserver from './observer/selectionobserver';
  19. import FocusObserver from './observer/focusobserver';
  20. import CompositionObserver from './observer/compositionobserver';
  21. import ObservableMixin from '@ckeditor/ckeditor5-utils/src/observablemixin';
  22. import log from '@ckeditor/ckeditor5-utils/src/log';
  23. import mix from '@ckeditor/ckeditor5-utils/src/mix';
  24. import { scrollViewportToShowTarget } from '@ckeditor/ckeditor5-utils/src/dom/scroll';
  25. import { injectUiElementHandling } from './uielement';
  26. import { injectQuirksHandling } from './filler';
  27. import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
  28. /**
  29. * Editor's view controller class. Its main responsibility is DOM - View management for editing purposes, to provide
  30. * abstraction over the DOM structure and events and hide all browsers quirks.
  31. *
  32. * View controller renders view document to DOM whenever view structure changes. To determine when view can be rendered,
  33. * all changes need to be done using the {@link module:engine/view/view~View#change} method, using
  34. * {@link module:engine/view/downcastwriter~DowncastWriter}:
  35. *
  36. * view.change( writer => {
  37. * writer.insert( position, writer.createText( 'foo' ) );
  38. * } );
  39. *
  40. * View controller also register {@link module:engine/view/observer/observer~Observer observers} which observes changes
  41. * on DOM and fire events on the {@link module:engine/view/document~Document Document}.
  42. * Note that the following observers are added by the class constructor and are always available:
  43. *
  44. * * {@link module:engine/view/observer/mutationobserver~MutationObserver},
  45. * * {@link module:engine/view/observer/selectionobserver~SelectionObserver},
  46. * * {@link module:engine/view/observer/focusobserver~FocusObserver},
  47. * * {@link module:engine/view/observer/keyobserver~KeyObserver},
  48. * * {@link module:engine/view/observer/fakeselectionobserver~FakeSelectionObserver}.
  49. * * {@link module:engine/view/observer/compositionobserver~CompositionObserver}.
  50. *
  51. * This class also {@link module:engine/view/view~View#attachDomRoot binds the DOM and the view elements}.
  52. *
  53. * If you do not need full a DOM - view management, and only want to transform a tree of view elements to a tree of DOM
  54. * elements you do not need this controller. You can use the {@link module:engine/view/domconverter~DomConverter DomConverter} instead.
  55. *
  56. * @mixes module:utils/observablemixin~ObservableMixin
  57. */
  58. export default class View {
  59. constructor() {
  60. /**
  61. * Instance of the {@link module:engine/view/document~Document} associated with this view controller.
  62. *
  63. * @readonly
  64. * @type {module:engine/view/document~Document}
  65. */
  66. this.document = new Document();
  67. /**
  68. * Instance of the {@link module:engine/view/domconverter~DomConverter domConverter} use by
  69. * {@link module:engine/view/view~View#renderer renderer}
  70. * and {@link module:engine/view/observer/observer~Observer observers}.
  71. *
  72. * @readonly
  73. * @type {module:engine/view/domconverter~DomConverter}
  74. */
  75. this.domConverter = new DomConverter();
  76. /**
  77. * Instance of the {@link module:engine/view/renderer~Renderer renderer}.
  78. *
  79. * @protected
  80. * @type {module:engine/view/renderer~Renderer}
  81. */
  82. this._renderer = new Renderer( this.domConverter, this.document.selection );
  83. this._renderer.bind( 'isFocused' ).to( this.document );
  84. /**
  85. * Roots of the DOM tree. Map on the `HTMLElement`s with roots names as keys.
  86. *
  87. * @readonly
  88. * @type {Map.<String, HTMLElement>}
  89. */
  90. this.domRoots = new Map();
  91. /**
  92. * Map of registered {@link module:engine/view/observer/observer~Observer observers}.
  93. *
  94. * @private
  95. * @type {Map.<Function, module:engine/view/observer/observer~Observer>}
  96. */
  97. this._observers = new Map();
  98. /**
  99. * Is set to `true` when {@link #change view changes} are currently in progress.
  100. *
  101. * @private
  102. * @type {Boolean}
  103. */
  104. this._ongoingChange = false;
  105. /**
  106. * Used to prevent calling {@link #render} and {@link #change} during rendering view to the DOM.
  107. *
  108. * @private
  109. * @type {Boolean}
  110. */
  111. this._renderingInProgress = false;
  112. /**
  113. * Used to prevent calling {@link #render} and {@link #change} during rendering view to the DOM.
  114. *
  115. * @private
  116. * @type {Boolean}
  117. */
  118. this._postFixersInProgress = false;
  119. /**
  120. * Internal flag to temporary disable rendering. See the usage in the {@link #_disableRendering}.
  121. *
  122. * @private
  123. * @type {Boolean}
  124. */
  125. this._renderingDisabled = false;
  126. /**
  127. * Internal flag that disables rendering when there are no changes since the last rendering.
  128. * It stores information about changed selection and changed elements from attached document roots.
  129. *
  130. * @private
  131. * @type {Boolean}
  132. */
  133. this._hasChangedSinceTheLastRendering = false;
  134. /**
  135. * DowncastWriter instance used in {@link #change change method} callbacks.
  136. *
  137. * @private
  138. * @type {module:engine/view/downcastwriter~DowncastWriter}
  139. */
  140. this._writer = new DowncastWriter( this.document );
  141. // Add default observers.
  142. this.addObserver( MutationObserver );
  143. this.addObserver( SelectionObserver );
  144. this.addObserver( FocusObserver );
  145. this.addObserver( KeyObserver );
  146. this.addObserver( FakeSelectionObserver );
  147. this.addObserver( CompositionObserver );
  148. // Inject quirks handlers.
  149. injectQuirksHandling( this );
  150. injectUiElementHandling( this );
  151. // Use 'normal' priority so that rendering is performed as first when using that priority.
  152. this.on( 'render', () => {
  153. this._render();
  154. // Informs that layout has changed after render.
  155. this.document.fire( 'layoutChanged' );
  156. // Reset the `_hasChangedSinceTheLastRendering` flag after rendering.
  157. this._hasChangedSinceTheLastRendering = false;
  158. } );
  159. // Listen to the document selection changes directly.
  160. this.listenTo( this.document.selection, 'change', () => {
  161. this._hasChangedSinceTheLastRendering = true;
  162. } );
  163. }
  164. /**
  165. * Attaches DOM root element to the view element and enable all observers on that element.
  166. * Also {@link module:engine/view/renderer~Renderer#markToSync mark element} to be synchronized with the view
  167. * what means that all child nodes will be removed and replaced with content of the view root.
  168. *
  169. * This method also will change view element name as the same as tag name of given dom root.
  170. * Name is always transformed to lower case.
  171. *
  172. * @param {Element} domRoot DOM root element.
  173. * @param {String} [name='main'] Name of the root.
  174. */
  175. attachDomRoot( domRoot, name = 'main' ) {
  176. const viewRoot = this.document.getRoot( name );
  177. // Set view root name the same as DOM root tag name.
  178. viewRoot._name = domRoot.tagName.toLowerCase();
  179. this.domRoots.set( name, domRoot );
  180. this.domConverter.bindElements( domRoot, viewRoot );
  181. this._renderer.markToSync( 'children', viewRoot );
  182. this._renderer.domDocuments.add( domRoot.ownerDocument );
  183. viewRoot.on( 'change:children', ( evt, node ) => this._renderer.markToSync( 'children', node ) );
  184. viewRoot.on( 'change:attributes', ( evt, node ) => this._renderer.markToSync( 'attributes', node ) );
  185. viewRoot.on( 'change:text', ( evt, node ) => this._renderer.markToSync( 'text', node ) );
  186. viewRoot.on( 'change', () => {
  187. this._hasChangedSinceTheLastRendering = true;
  188. } );
  189. for ( const observer of this._observers.values() ) {
  190. observer.observe( domRoot, name );
  191. }
  192. }
  193. /**
  194. * Gets DOM root element.
  195. *
  196. * @param {String} [name='main'] Name of the root.
  197. * @returns {Element} DOM root element instance.
  198. */
  199. getDomRoot( name = 'main' ) {
  200. return this.domRoots.get( name );
  201. }
  202. /**
  203. * Creates observer of the given type if not yet created, {@link module:engine/view/observer/observer~Observer#enable enables} it
  204. * and {@link module:engine/view/observer/observer~Observer#observe attaches} to all existing and future
  205. * {@link #domRoots DOM roots}.
  206. *
  207. * Note: Observers are recognized by their constructor (classes). A single observer will be instantiated and used only
  208. * when registered for the first time. This means that features and other components can register a single observer
  209. * multiple times without caring whether it has been already added or not.
  210. *
  211. * @param {Function} Observer The constructor of an observer to add.
  212. * Should create an instance inheriting from {@link module:engine/view/observer/observer~Observer}.
  213. * @returns {module:engine/view/observer/observer~Observer} Added observer instance.
  214. */
  215. addObserver( Observer ) {
  216. let observer = this._observers.get( Observer );
  217. if ( observer ) {
  218. return observer;
  219. }
  220. observer = new Observer( this );
  221. this._observers.set( Observer, observer );
  222. for ( const [ name, domElement ] of this.domRoots ) {
  223. observer.observe( domElement, name );
  224. }
  225. observer.enable();
  226. return observer;
  227. }
  228. /**
  229. * Returns observer of the given type or `undefined` if such observer has not been added yet.
  230. *
  231. * @param {Function} Observer The constructor of an observer to get.
  232. * @returns {module:engine/view/observer/observer~Observer|undefined} Observer instance or undefined.
  233. */
  234. getObserver( Observer ) {
  235. return this._observers.get( Observer );
  236. }
  237. /**
  238. * Disables all added observers.
  239. */
  240. disableObservers() {
  241. for ( const observer of this._observers.values() ) {
  242. observer.disable();
  243. }
  244. }
  245. /**
  246. * Enables all added observers.
  247. */
  248. enableObservers() {
  249. for ( const observer of this._observers.values() ) {
  250. observer.enable();
  251. }
  252. }
  253. /**
  254. * Scrolls the page viewport and {@link #domRoots} with their ancestors to reveal the
  255. * caret, if not already visible to the user.
  256. */
  257. scrollToTheSelection() {
  258. const range = this.document.selection.getFirstRange();
  259. if ( range ) {
  260. scrollViewportToShowTarget( {
  261. target: this.domConverter.viewRangeToDom( range ),
  262. viewportOffset: 20
  263. } );
  264. }
  265. }
  266. /**
  267. * It will focus DOM element representing {@link module:engine/view/editableelement~EditableElement EditableElement}
  268. * that is currently having selection inside.
  269. */
  270. focus() {
  271. if ( !this.document.isFocused ) {
  272. const editable = this.document.selection.editableElement;
  273. if ( editable ) {
  274. this.domConverter.focus( editable );
  275. this.forceRender();
  276. } else {
  277. /**
  278. * Before focusing view document, selection should be placed inside one of the view's editables.
  279. * Normally its selection will be converted from model document (which have default selection), but
  280. * when using view document on its own, we need to manually place selection before focusing it.
  281. *
  282. * @error view-focus-no-selection
  283. */
  284. log.warn( 'view-focus-no-selection: There is no selection in any editable to focus.' );
  285. }
  286. }
  287. }
  288. /**
  289. * The `change()` method is the primary way of changing the view. You should use it to modify any node in the view tree.
  290. * It makes sure that after all changes are made the view is rendered to the DOM (assuming that the view will be changed
  291. * inside the callback). It prevents situations when the DOM is updated when the view state is not yet correct.It allows
  292. * to nest calls one inside another and still performs a single rendering after all those changes are made.
  293. * It also returns the return value of its callback.
  294. *
  295. * const text = view.change( writer => {
  296. * const newText = writer.createText( 'foo' );
  297. * writer.insert( position1, newText );
  298. *
  299. * view.change( writer => {
  300. * writer.insert( position2, writer.createText( 'bar' ) );
  301. * } );
  302. *
  303. * writer.remove( range );
  304. *
  305. * return newText;
  306. * } );
  307. *
  308. * When the outermost change block is done and rendering to the DOM is over the
  309. * {@link module:engine/view/view~View#event:render `View#render`} event is fired.
  310. *
  311. * This method throws a `applying-view-changes-on-rendering` error when
  312. * the change block is used after rendering to the DOM has started.
  313. *
  314. * @param {Function} callback Callback function which may modify the view.
  315. * @returns {*} Value returned by the callback.
  316. */
  317. change( callback ) {
  318. if ( this._renderingInProgress || this._postFixersInProgress ) {
  319. /**
  320. * Thrown when there is an attempt to make changes to the view tree when it is in incorrect state. This may
  321. * cause some unexpected behaviour and inconsistency between the DOM and the view.
  322. * This may be caused by:
  323. *
  324. * * calling {@link #change} or {@link #render} during rendering process,
  325. * * calling {@link #change} or {@link #render} inside of
  326. * {@link module:engine/view/document~Document#registerPostFixer post-fixer function}.
  327. *
  328. * @error cannot-change-view-tree
  329. */
  330. throw new CKEditorError(
  331. 'cannot-change-view-tree: ' +
  332. 'Attempting to make changes to the view when it is in an incorrect state: rendering or post-fixers are in progress. ' +
  333. 'This may cause some unexpected behavior and inconsistency between the DOM and the view.'
  334. );
  335. }
  336. // Recursive call to view.change() method - execute listener immediately.
  337. if ( this._ongoingChange ) {
  338. return callback( this._writer );
  339. }
  340. // This lock will assure that all recursive calls to view.change() will end up in same block - one "render"
  341. // event for all nested calls.
  342. this._ongoingChange = true;
  343. const callbackResult = callback( this._writer );
  344. this._ongoingChange = false;
  345. // This lock is used by editing controller to render changes from outer most model.change() once. As plugins might call
  346. // view.change() inside model.change() block - this will ensures that postfixers and rendering are called once after all changes.
  347. // Also, we don't need to render anything if there're no changes since last rendering.
  348. if ( !this._renderingDisabled && this._hasChangedSinceTheLastRendering ) {
  349. this._postFixersInProgress = true;
  350. this.document._callPostFixers( this._writer );
  351. this._postFixersInProgress = false;
  352. this.fire( 'render' );
  353. }
  354. return callbackResult;
  355. }
  356. render() {
  357. console.log( 'deprecated usage.' );
  358. this.forceRender();
  359. }
  360. /**
  361. * Renders {@link module:engine/view/document~Document view document} to DOM. If any view changes are
  362. * currently in progress, rendering will start after all {@link #change change blocks} are processed.
  363. *
  364. * Throws {@link module:utils/ckeditorerror~CKEditorError CKEditorError} `applying-view-changes-on-rendering` when
  365. * trying to re-render when rendering to DOM has already started.
  366. */
  367. forceRender() {
  368. this._hasChangedSinceTheLastRendering = true;
  369. this.change( () => {} );
  370. }
  371. /**
  372. * Destroys this instance. Makes sure that all observers are destroyed and listeners removed.
  373. */
  374. destroy() {
  375. for ( const observer of this._observers.values() ) {
  376. observer.destroy();
  377. }
  378. this.document.destroy();
  379. this.stopListening();
  380. }
  381. /**
  382. * Creates position at the given location. The location can be specified as:
  383. *
  384. * * a {@link module:engine/view/position~Position position},
  385. * * parent element and offset (offset defaults to `0`),
  386. * * parent element and `'end'` (sets position at the end of that element),
  387. * * {@link module:engine/view/item~Item view item} and `'before'` or `'after'` (sets position before or after given view item).
  388. *
  389. * This method is a shortcut to other constructors such as:
  390. *
  391. * * {@link #createPositionBefore},
  392. * * {@link #createPositionAfter},
  393. *
  394. * @param {module:engine/view/item~Item|module:engine/model/position~Position} itemOrPosition
  395. * @param {Number|'end'|'before'|'after'} [offset] Offset or one of the flags. Used only when
  396. * first parameter is a {@link module:engine/view/item~Item view item}.
  397. */
  398. createPositionAt( itemOrPosition, offset ) {
  399. return Position._createAt( itemOrPosition, offset );
  400. }
  401. /**
  402. * Creates a new position after given view item.
  403. *
  404. * @param {module:engine/view/item~Item} item View item after which the position should be located.
  405. * @returns {module:engine/view/position~Position}
  406. */
  407. createPositionAfter( item ) {
  408. return Position._createAfter( item );
  409. }
  410. /**
  411. * Creates a new position before given view item.
  412. *
  413. * @param {module:engine/view/item~Item} item View item before which the position should be located.
  414. * @returns {module:engine/view/position~Position}
  415. */
  416. createPositionBefore( item ) {
  417. return Position._createBefore( item );
  418. }
  419. /**
  420. * Creates a range spanning from `start` position to `end` position.
  421. *
  422. * **Note:** This factory method creates it's own {@link module:engine/view/position~Position} instances basing on passed values.
  423. *
  424. * @param {module:engine/view/position~Position} start Start position.
  425. * @param {module:engine/view/position~Position} [end] End position. If not set, range will be collapsed at `start` position.
  426. * @returns {module:engine/view/range~Range}
  427. */
  428. createRange( start, end ) {
  429. return new Range( start, end );
  430. }
  431. /**
  432. * Creates a range that starts before given {@link module:engine/view/item~Item view item} and ends after it.
  433. *
  434. * @param {module:engine/view/item~Item} item
  435. * @returns {module:engine/view/range~Range}
  436. */
  437. createRangeOn( item ) {
  438. return Range._createOn( item );
  439. }
  440. /**
  441. * Creates a range inside an {@link module:engine/view/element~Element element} which starts before the first child of
  442. * that element and ends after the last child of that element.
  443. *
  444. * @param {module:engine/view/element~Element} element Element which is a parent for the range.
  445. * @returns {module:engine/view/range~Range}
  446. */
  447. createRangeIn( element ) {
  448. return Range._createIn( element );
  449. }
  450. /**
  451. Creates new {@link module:engine/view/selection~Selection} instance.
  452. *
  453. * // Creates empty selection without ranges.
  454. * const selection = view.createSelection();
  455. *
  456. * // Creates selection at the given range.
  457. * const range = view.createRange( start, end );
  458. * const selection = view.createSelection( range );
  459. *
  460. * // Creates selection at the given ranges
  461. * const ranges = [ view.createRange( start1, end2 ), view.createRange( star2, end2 ) ];
  462. * const selection = view.createSelection( ranges );
  463. *
  464. * // Creates selection from the other selection.
  465. * const otherSelection = view.createSelection();
  466. * const selection = view.createSelection( otherSelection );
  467. *
  468. * // Creates selection from the document selection.
  469. * const selection = view.createSelection( editor.editing.view.document.selection );
  470. *
  471. * // Creates selection at the given position.
  472. * const position = view.createPositionFromPath( root, path );
  473. * const selection = view.createSelection( position );
  474. *
  475. * // Creates collapsed selection at the position of given item and offset.
  476. * const paragraph = view.createContainerElement( 'paragraph' );
  477. * const selection = view.createSelection( paragraph, offset );
  478. *
  479. * // Creates a range inside an {@link module:engine/view/element~Element element} which starts before the
  480. * // first child of that element and ends after the last child of that element.
  481. * const selection = view.createSelection( paragraph, 'in' );
  482. *
  483. * // Creates a range on an {@link module:engine/view/item~Item item} which starts before the item and ends
  484. * // just after the item.
  485. * const selection = view.createSelection( paragraph, 'on' );
  486. *
  487. * `Selection`'s factory method allow passing additional options (`backward`, `fake` and `label`) as the last argument.
  488. *
  489. * // Creates backward selection.
  490. * const selection = view.createSelection( range, { backward: true } );
  491. *
  492. * Fake selection does not render as browser native selection over selected elements and is hidden to the user.
  493. * This way, no native selection UI artifacts are displayed to the user and selection over elements can be
  494. * represented in other way, for example by applying proper CSS class.
  495. *
  496. * Additionally fake's selection label can be provided. It will be used to describe fake selection in DOM
  497. * (and be properly handled by screen readers).
  498. *
  499. * // Creates fake selection with label.
  500. * const selection = view.createSelection( range, { fake: true, label: 'foo' } );
  501. *
  502. * @param {module:engine/view/selection~Selectable} [selectable=null]
  503. * @param {Number|'before'|'end'|'after'|'on'|'in'} [placeOrOffset] Offset or place when selectable is an `Item`.
  504. * @param {Object} [options]
  505. * @param {Boolean} [options.backward] Sets this selection instance to be backward.
  506. * @param {Boolean} [options.fake] Sets this selection instance to be marked as `fake`.
  507. * @param {String} [options.label] Label for the fake selection.
  508. * @returns {module:engine/view/selection~Selection}
  509. */
  510. createSelection( selectable, placeOrOffset, options ) {
  511. return new Selection( selectable, placeOrOffset, options );
  512. }
  513. /**
  514. * Disables or enables rendering. If the flag is set to `true` then the rendering will be disabled.
  515. * If the flag is set to `false` and if there was some change in the meantime, then the rendering action will be performed.
  516. *
  517. * @protected
  518. * @param {Boolean} flag A flag indicates whether the rendering should be disabled.
  519. */
  520. _disableRendering( flag ) {
  521. this._renderingDisabled = flag;
  522. if ( flag == false ) {
  523. // Render when you stop blocking rendering.
  524. this.change( () => {} );
  525. }
  526. }
  527. /**
  528. * Renders all changes. In order to avoid triggering the observers (e.g. mutations) all observers are disabled
  529. * before rendering and re-enabled after that.
  530. *
  531. * @private
  532. */
  533. _render() {
  534. this._renderingInProgress = true;
  535. this.disableObservers();
  536. this._renderer.render();
  537. this.enableObservers();
  538. this._renderingInProgress = false;
  539. }
  540. /**
  541. * Fired after a topmost {@link module:engine/view/view~View#change change block} and all
  542. * {@link module:engine/view/document~Document#registerPostFixer post-fixers} are executed.
  543. *
  544. * Actual rendering is performed as a first listener on 'normal' priority.
  545. *
  546. * view.on( 'render', () => {
  547. * // Rendering to the DOM is complete.
  548. * } );
  549. *
  550. * This event is useful when you want to update interface elements after the rendering, e.g. position of the
  551. * balloon panel. If you wants to change view structure use
  552. * {@link module:engine/view/document~Document#registerPostFixer post-fixers}.
  553. *
  554. * @event module:engine/view/view~View#event:render
  555. */
  556. }
  557. mix( View, ObservableMixin );