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view.js 14 KB

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  1. /**
  2. * @license Copyright (c) 2003-2018, 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 Writer from './writer';
  10. import Renderer from './renderer';
  11. import DomConverter from './domconverter';
  12. import MutationObserver from './observer/mutationobserver';
  13. import KeyObserver from './observer/keyobserver';
  14. import FakeSelectionObserver from './observer/fakeselectionobserver';
  15. import SelectionObserver from './observer/selectionobserver';
  16. import FocusObserver from './observer/focusobserver';
  17. import ObservableMixin from '@ckeditor/ckeditor5-utils/src/observablemixin';
  18. import log from '@ckeditor/ckeditor5-utils/src/log';
  19. import mix from '@ckeditor/ckeditor5-utils/src/mix';
  20. import { scrollViewportToShowTarget } from '@ckeditor/ckeditor5-utils/src/dom/scroll';
  21. import { injectUiElementHandling } from './uielement';
  22. import { injectQuirksHandling } from './filler';
  23. import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
  24. /**
  25. * Editor's view controller class. Its main responsibility is DOM - View management for editing purposes, to provide
  26. * abstraction over the DOM structure and events and hide all browsers quirks.
  27. *
  28. * View controller renders view document to DOM whenever view structure changes. To determine when view can be rendered,
  29. * all changes need to be done using the {@link module:engine/view/view~View#change} method, using
  30. * {@link module:engine/view/writer~Writer}:
  31. *
  32. * view.change( writer => {
  33. * writer.insert( position, writer.createText( 'foo' ) );
  34. * } );
  35. *
  36. * View controller also register {@link module:engine/view/observer/observer~Observer observers} which observes changes
  37. * on DOM and fire events on the {@link module:engine/view/document~Document Document}.
  38. * Note that the following observers are added by the class constructor and are always available:
  39. *
  40. * * {@link module:engine/view/observer/mutationobserver~MutationObserver},
  41. * * {@link module:engine/view/observer/selectionobserver~SelectionObserver},
  42. * * {@link module:engine/view/observer/focusobserver~FocusObserver},
  43. * * {@link module:engine/view/observer/keyobserver~KeyObserver},
  44. * * {@link module:engine/view/observer/fakeselectionobserver~FakeSelectionObserver}.
  45. *
  46. * This class also {@link module:engine/view/view~View#attachDomRoot bind DOM and View elements}.
  47. *
  48. * If you do not need full DOM - View management, and want to only transform the tree of view elements to the DOM
  49. * elements you do not need this controller, you can use the {@link module:engine/view/domconverter~DomConverter DomConverter}.
  50. *
  51. * @mixes module:utils/observablemixin~ObservableMixin
  52. */
  53. export default class View {
  54. constructor() {
  55. /**
  56. * Instance of the {@link module:engine/view/document~Document} associated with this view controller.
  57. *
  58. * @readonly
  59. * @member {module:engine/view/document~Document} module:engine/view/view~View#document
  60. */
  61. this.document = new Document();
  62. /**
  63. * Instance of the {@link module:engine/view/domconverter~DomConverter domConverter} use by
  64. * {@link module:engine/view/view~View#renderer renderer}
  65. * and {@link module:engine/view/observer/observer~Observer observers}.
  66. *
  67. * @readonly
  68. * @member {module:engine/view/domconverter~DomConverter} module:engine/view/view~View#domConverter
  69. */
  70. this.domConverter = new DomConverter();
  71. /**
  72. * Instance of the {@link module:engine/view/renderer~Renderer renderer}.
  73. *
  74. * @protected
  75. * @member {module:engine/view/renderer~Renderer} module:engine/view/view~View#renderer
  76. */
  77. this._renderer = new Renderer( this.domConverter, this.document.selection );
  78. this._renderer.bind( 'isFocused' ).to( this.document );
  79. /**
  80. * Roots of the DOM tree. Map on the `HTMLElement`s with roots names as keys.
  81. *
  82. * @readonly
  83. * @member {Map} module:engine/view/view~View#domRoots
  84. */
  85. this.domRoots = new Map();
  86. /**
  87. * Map of registered {@link module:engine/view/observer/observer~Observer observers}.
  88. *
  89. * @private
  90. * @member {Map.<Function, module:engine/view/observer/observer~Observer>} module:engine/view/view~View#_observers
  91. */
  92. this._observers = new Map();
  93. /**
  94. * Is set to `true` when {@link #change view changes} are currently in progress.
  95. *
  96. * @private
  97. * @member {Boolean} module:engine/view/view~View#_ongoingChange
  98. */
  99. this._ongoingChange = false;
  100. /**
  101. * Used to prevent calling {@link #render} and {@link #change} during rendering view to the DOM.
  102. *
  103. * @private
  104. * @member {Boolean} module:engine/view/view~View#_renderingInProgress
  105. */
  106. this._renderingInProgress = false;
  107. /**
  108. * Used to prevent calling {@link #render} and {@link #change} during rendering view to the DOM.
  109. *
  110. * @private
  111. * @member {Boolean} module:engine/view/view~View#_renderingInProgress
  112. */
  113. this._postFixersInProgress = false;
  114. /**
  115. * Writer instance used in {@link #change change method) callbacks.
  116. *
  117. * @private
  118. * @member {module:engine/view/writer~Writer} module:engine/view/view~View#_writer
  119. */
  120. this._writer = new Writer( this.document );
  121. // Add default observers.
  122. this.addObserver( MutationObserver );
  123. this.addObserver( SelectionObserver );
  124. this.addObserver( FocusObserver );
  125. this.addObserver( KeyObserver );
  126. this.addObserver( FakeSelectionObserver );
  127. // Inject quirks handlers.
  128. injectQuirksHandling( this );
  129. injectUiElementHandling( this );
  130. // Use 'normal' priority so that rendering is performed as first when using that priority.
  131. this.on( 'render', () => {
  132. this._render();
  133. } );
  134. }
  135. /**
  136. * Attaches DOM root element to the view element and enable all observers on that element.
  137. * Also {@link module:engine/view/renderer~Renderer#markToSync mark element} to be synchronized with the view
  138. * what means that all child nodes will be removed and replaced with content of the view root.
  139. *
  140. * This method also will change view element name as the same as tag name of given dom root.
  141. * Name is always transformed to lower case.
  142. *
  143. * @param {Element} domRoot DOM root element.
  144. * @param {String} [name='main'] Name of the root.
  145. */
  146. attachDomRoot( domRoot, name = 'main' ) {
  147. const viewRoot = this.document.getRoot( name );
  148. // Set view root name the same as DOM root tag name.
  149. viewRoot._name = domRoot.tagName.toLowerCase();
  150. this.domRoots.set( name, domRoot );
  151. this.domConverter.bindElements( domRoot, viewRoot );
  152. this._renderer.markToSync( 'children', viewRoot );
  153. this._renderer.domDocuments.add( domRoot.ownerDocument );
  154. viewRoot.on( 'change:children', ( evt, node ) => this._renderer.markToSync( 'children', node ) );
  155. viewRoot.on( 'change:attributes', ( evt, node ) => this._renderer.markToSync( 'attributes', node ) );
  156. viewRoot.on( 'change:text', ( evt, node ) => this._renderer.markToSync( 'text', node ) );
  157. for ( const observer of this._observers.values() ) {
  158. observer.observe( domRoot, name );
  159. }
  160. }
  161. /**
  162. * Gets DOM root element.
  163. *
  164. * @param {String} [name='main'] Name of the root.
  165. * @returns {Element} DOM root element instance.
  166. */
  167. getDomRoot( name = 'main' ) {
  168. return this.domRoots.get( name );
  169. }
  170. /**
  171. * Creates observer of the given type if not yet created, {@link module:engine/view/observer/observer~Observer#enable enables} it
  172. * and {@link module:engine/view/observer/observer~Observer#observe attaches} to all existing and future
  173. * {@link #domRoots DOM roots}.
  174. *
  175. * Note: Observers are recognized by their constructor (classes). A single observer will be instantiated and used only
  176. * when registered for the first time. This means that features and other components can register a single observer
  177. * multiple times without caring whether it has been already added or not.
  178. *
  179. * @param {Function} Observer The constructor of an observer to add.
  180. * Should create an instance inheriting from {@link module:engine/view/observer/observer~Observer}.
  181. * @returns {module:engine/view/observer/observer~Observer} Added observer instance.
  182. */
  183. addObserver( Observer ) {
  184. let observer = this._observers.get( Observer );
  185. if ( observer ) {
  186. return observer;
  187. }
  188. observer = new Observer( this );
  189. this._observers.set( Observer, observer );
  190. for ( const [ name, domElement ] of this.domRoots ) {
  191. observer.observe( domElement, name );
  192. }
  193. observer.enable();
  194. return observer;
  195. }
  196. /**
  197. * Returns observer of the given type or `undefined` if such observer has not been added yet.
  198. *
  199. * @param {Function} Observer The constructor of an observer to get.
  200. * @returns {module:engine/view/observer/observer~Observer|undefined} Observer instance or undefined.
  201. */
  202. getObserver( Observer ) {
  203. return this._observers.get( Observer );
  204. }
  205. /**
  206. * Disables all added observers.
  207. */
  208. disableObservers() {
  209. for ( const observer of this._observers.values() ) {
  210. observer.disable();
  211. }
  212. }
  213. /**
  214. * Enables all added observers.
  215. */
  216. enableObservers() {
  217. for ( const observer of this._observers.values() ) {
  218. observer.enable();
  219. }
  220. }
  221. /**
  222. * Scrolls the page viewport and {@link #domRoots} with their ancestors to reveal the
  223. * caret, if not already visible to the user.
  224. */
  225. scrollToTheSelection() {
  226. const range = this.document.selection.getFirstRange();
  227. if ( range ) {
  228. scrollViewportToShowTarget( {
  229. target: this.domConverter.viewRangeToDom( range ),
  230. viewportOffset: 20
  231. } );
  232. }
  233. }
  234. /**
  235. * It will focus DOM element representing {@link module:engine/view/editableelement~EditableElement EditableElement}
  236. * that is currently having selection inside.
  237. */
  238. focus() {
  239. if ( !this.document.isFocused ) {
  240. const editable = this.document.selection.editableElement;
  241. if ( editable ) {
  242. this.domConverter.focus( editable );
  243. this.render();
  244. } else {
  245. /**
  246. * Before focusing view document, selection should be placed inside one of the view's editables.
  247. * Normally its selection will be converted from model document (which have default selection), but
  248. * when using view document on its own, we need to manually place selection before focusing it.
  249. *
  250. * @error view-focus-no-selection
  251. */
  252. log.warn( 'view-focus-no-selection: There is no selection in any editable to focus.' );
  253. }
  254. }
  255. }
  256. /**
  257. * Change method is the primary way of changing the view. You should use it to modify any node in the view tree.
  258. * It makes sure that after all changes are made view is rendered to DOM. It prevents situations when DOM is updated
  259. * when view state is not yet correct. It allows to nest calls one inside another and still perform single rendering
  260. * after all changes are applied.
  261. *
  262. * view.change( writer => {
  263. * writer.insert( position1, writer.createText( 'foo' ) );
  264. *
  265. * view.change( writer => {
  266. * writer.insert( position2, writer.createText( 'bar' ) );
  267. * } );
  268. *
  269. * writer.remove( range );
  270. * } );
  271. *
  272. * Change block is executed immediately.
  273. *
  274. * When the outermost change block is done and rendering to DOM is over it fires
  275. * {@link module:engine/view/view~View#event:render} event.
  276. *
  277. * Throws {@link module:utils/ckeditorerror~CKEditorError CKEditorError} `applying-view-changes-on-rendering` when
  278. * change block is used after rendering to DOM has started.
  279. *
  280. * @param {Function} callback Callback function which may modify the view.
  281. */
  282. change( callback ) {
  283. if ( this._renderingInProgress || this._postFixersInProgress ) {
  284. /**
  285. * Thrown when there is an attempt to make changes to the view tree when it is in incorrect state. This may
  286. * cause some unexpected behaviour and inconsistency between the DOM and the view.
  287. * This may be caused by:
  288. * * calling {@link #change} or {@link #render} during rendering process,
  289. * * calling {@link #change} or {@link #render} inside of
  290. * {@link module:engine/view/document~Document#registerPostFixer post fixer function}.
  291. */
  292. throw new CKEditorError(
  293. 'cannot-change-view-tree: ' +
  294. 'Attempting to make changes to the view when it is in incorrect state: rendering or post fixers are in progress. ' +
  295. 'This may cause some unexpected behaviour and inconsistency between the DOM and the view.'
  296. );
  297. }
  298. // Recursive call to view.change() method - execute listener immediately.
  299. if ( this._ongoingChange ) {
  300. callback( this._writer );
  301. return;
  302. }
  303. // This lock will assure that all recursive calls to view.change() will end up in same block - one "render"
  304. // event for all nested calls.
  305. this._ongoingChange = true;
  306. callback( this._writer );
  307. this._ongoingChange = false;
  308. // Execute all document post fixers after the change.
  309. this._postFixersInProgress = true;
  310. this.document._callPostFixers( this._writer );
  311. this._postFixersInProgress = false;
  312. this.fire( 'render' );
  313. }
  314. /**
  315. * Renders {@link module:engine/view/document~Document view document} to DOM. If any view changes are
  316. * currently in progress, rendering will start after all {@link #change change blocks} are processed.
  317. *
  318. * Throws {@link module:utils/ckeditorerror~CKEditorError CKEditorError} `applying-view-changes-on-rendering` when
  319. * trying to re-render when rendering to DOM has already started.
  320. */
  321. render() {
  322. this.change( () => {} );
  323. }
  324. /**
  325. * Destroys this instance. Makes sure that all observers are destroyed and listeners removed.
  326. */
  327. destroy() {
  328. for ( const observer of this._observers.values() ) {
  329. observer.destroy();
  330. }
  331. this.stopListening();
  332. }
  333. /**
  334. * Renders all changes. In order to avoid triggering the observers (e.g. mutations) all observers are disabled
  335. * before rendering and re-enabled after that.
  336. *
  337. * @private
  338. */
  339. _render() {
  340. this._renderingInProgress = true;
  341. this.disableObservers();
  342. this._renderer.render();
  343. this.enableObservers();
  344. this._renderingInProgress = false;
  345. }
  346. /**
  347. * Fired after a topmost {@link module:engine/view/view~View#change change block} and all
  348. * {@link module:engine/view/document~Document#registerPostFixer post fixers} are executed.
  349. *
  350. * Actual rendering is performed as a first listener on 'normal' priority.
  351. *
  352. * view.on( 'render', () => {
  353. * // Rendering to the DOM is complete.
  354. * } );
  355. *
  356. * This event is useful when you want to update interface elements after the rendering, e.g. position of the
  357. * balloon panel. If you wants to change view structure use
  358. * {@link module:engine/view/document~Document#registerPostFixer post fixers}.
  359. *
  360. * @event module:engine/view/view~View#event:render
  361. */
  362. }
  363. mix( View, ObservableMixin );