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viewconversiondispatcher.js 12 KB

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  1. /**
  2. * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md.
  4. */
  5. 'use strict';
  6. import ViewConsumable from './viewconsumable.js';
  7. import ViewElement from '../view/element.js';
  8. import ViewText from '../view/text.js';
  9. import EmitterMixin from '../../utils/emittermixin.js';
  10. import mix from '../../utils/mix.js';
  11. import extend from '../../utils/lib/lodash/extend.js';
  12. /**
  13. * `ViewConversionDispatcher` is a central point of {@link engine.view view} conversion, which is a process of
  14. * converting given {@link engine.view.DocumentFragment view document fragment} or {@link engine.view.Element}
  15. * into another structure. In default application, {@link engine.view view} is converted to {@link engine.model}.
  16. *
  17. * During conversion process, for all {@link engine.view.Node view nodes} from the converted view document fragment,
  18. * `ViewConversionDispatcher` fires corresponding events. Special callbacks called "converters" should listen to
  19. * `ViewConversionDispatcher` for those events.
  20. *
  21. * Each callback, as a first argument, is passed a special object `data` that has `input` and `output` properties.
  22. * `input` property contains {@link engine.view.Node view node} or {@link engine.view.DocumentFragment view document fragment}
  23. * that is converted at the moment and might be handled by the callback. `output` property should be used to save the result
  24. * of conversion. Keep in mind that the `data` parameter is customizable and may contain other values - see
  25. * {@link engine.conversion.ViewConversionDispatcher#convert}. It is also shared by reference by all callbacks
  26. * listening to given event. **Note**: in view to model conversion - `data` contains `context` property that is an array
  27. * of {@link engine.model.Element model elements}. These are model elements that will be the parent of currently
  28. * converted view item. `context` property is used in examples below.
  29. *
  30. * The second parameter passed to a callback is an instance of {@link engine.conversion.ViewConsumable}. It stores
  31. * information about what parts of processed view item are still waiting to be handled. After a piece of view item
  32. * was converted, appropriate consumable value should be {@link engine.conversion.ViewConsumable#consume consumed}.
  33. *
  34. * The third parameter passed to a callback is an instance of {@link engine.conversion.ViewConversionDispatcher}
  35. * which provides additional tools for converters.
  36. *
  37. * Examples of providing callbacks for `ViewConversionDispatcher`:
  38. *
  39. * // Converter for paragraphs (<p>).
  40. * viewDispatcher.on( 'element:p', ( data, consumable, conversionApi ) => {
  41. * const paragraph = new ModelElement( 'paragraph' );
  42. * const schemaQuery = {
  43. * name: 'paragraph',
  44. * inside: data.context
  45. * };
  46. *
  47. * if ( conversionApi.schema.check( schemaQuery ) ) {
  48. * if ( !consumable.consume( data.input, { name: true } ) ) {
  49. * // Before converting this paragraph's children we have to update their context by this paragraph.
  50. * data.context.push( paragraph );
  51. * const children = conversionApi.convertChildren( data.input, consumable, data );
  52. * data.context.pop();
  53. * paragraph.appendChildren( children );
  54. * data.output = paragraph;
  55. * }
  56. * }
  57. * } );
  58. *
  59. * // Converter for links (<a>).
  60. * viewDispatcher.on( 'element:a', ( data, consumable, conversionApi ) => {
  61. * if ( consumable.consume( data.input, { name: true, attributes: [ 'href' ] } ) ) {
  62. * // <a> element is inline and is represented by an attribute in the model.
  63. * // This is why we are not updating `context` property.
  64. * data.output = conversionApi.convertChildren( data.input, consumable, data );
  65. *
  66. * for ( let item of Range.createFrom( data.output ) ) {
  67. * const schemaQuery = {
  68. * name: item.name || '$text',
  69. * attribute: 'link',
  70. * inside: data.context
  71. * };
  72. *
  73. * if ( conversionApi.schema.checkQuery( schemaQuery ) ) {
  74. * item.setAttribute( 'link', data.input.getAttribute( 'href' ) );
  75. * }
  76. * }
  77. * }
  78. * } );
  79. *
  80. * // Fire conversion.
  81. * // Always take care where the converted model structure will be appended to. If this `viewDocumentFragment`
  82. * // is going to be appended directly to a '$root' element, use that in `context`.
  83. * viewDispatcher.convert( viewDocumentFragment, { context: [ '$root' ] } );
  84. *
  85. * Before each conversion process, `ViewConversionDispatcher` fires {@link engine.conversion.ViewConversionDispatcher.viewCleanup}
  86. * event which can be used to prepare tree view for conversion.
  87. *
  88. * @mixes utils.EmitterMixin
  89. * @fires engine.conversion.ViewConversionDispatcher.viewCleanup
  90. * @fires engine.conversion.ViewConversionDispatcher.element
  91. * @fires engine.conversion.ViewConversionDispatcher.text
  92. * @fires engine.conversion.ViewConversionDispatcher.documentFragment
  93. *
  94. * @memberOf engine.conversion
  95. */
  96. export default class ViewConversionDispatcher {
  97. /**
  98. * Creates a `ViewConversionDispatcher` that operates using passed API.
  99. *
  100. * @see engine.conversion.ViewConversionApi
  101. * @param {Object} [conversionApi] Additional properties for interface that will be passed to events fired
  102. * by `ViewConversionDispatcher`.
  103. */
  104. constructor( conversionApi = {} ) {
  105. /**
  106. * Interface passed by dispatcher to the events callbacks.
  107. *
  108. * @member {engine.conversion.ViewConversionApi} engine.conversion.ViewConversionDispatcher#conversionApi
  109. */
  110. this.conversionApi = extend( {}, conversionApi );
  111. // `convertItem` and `convertChildren` are bound to this `ViewConversionDispatcher` instance and
  112. // set on `conversionApi`. This way only a part of `ViewConversionDispatcher` API is exposed.
  113. this.conversionApi.convertItem = this._convertItem.bind( this );
  114. this.conversionApi.convertChildren = this._convertChildren.bind( this );
  115. }
  116. /**
  117. * Starts the conversion process. The entry point for the conversion.
  118. *
  119. * @fires engine.conversion.ViewConversionDispatcher.element
  120. * @fires engine.conversion.ViewConversionDispatcher.text
  121. * @fires engine.conversion.ViewConversionDispatcher.documentFragment
  122. * @param {engine.view.DocumentFragment|engine.view.Element} viewItem Part of the view to be converted.
  123. * @param {Object} [additionalData] Additional data to be passed in `data` argument when firing `ViewConversionDispatcher`
  124. * events. See also {@link engine.conversion.ViewConversionDispatcher.element element event}.
  125. * @returns {engine.model.DocumentFragment} Model document fragment that is a result of the conversion process.
  126. */
  127. convert( viewItem, additionalData = {} ) {
  128. this.fire( 'viewCleanup', viewItem );
  129. const consumable = ViewConsumable.createFrom( viewItem );
  130. return this._convertItem( viewItem, consumable, additionalData );
  131. }
  132. /**
  133. * @private
  134. * @see engine.conversion.ViewConversionApi#convertItem
  135. */
  136. _convertItem( input, consumable, additionalData = {} ) {
  137. const data = extend( {}, additionalData, {
  138. input: input,
  139. output: null
  140. } );
  141. if ( input instanceof ViewElement ) {
  142. this.fire( 'element:' + input.name, data, consumable, this.conversionApi );
  143. } else if ( input instanceof ViewText ) {
  144. this.fire( 'text', data, consumable, this.conversionApi );
  145. } else {
  146. this.fire( 'documentFragment', data, consumable, this.conversionApi );
  147. }
  148. return data.output;
  149. }
  150. /**
  151. * @private
  152. * @see engine.conversion.ViewConversionApi#convertChildren
  153. */
  154. _convertChildren( input, consumable, additionalData = {} ) {
  155. const viewChildren = Array.from( input.getChildren() );
  156. const convertedChildren = viewChildren.map( ( viewChild ) => this._convertItem( viewChild, consumable, additionalData ) );
  157. // Flatten and remove nulls.
  158. return convertedChildren.reduce( ( a, b ) => b ? a.concat( b ) : a, [] );
  159. }
  160. /**
  161. * Fired before the first conversion event, at the beginning of view to model conversion process.
  162. *
  163. * @event engine.conversion.ViewConversionDispatcher.viewCleanup
  164. * @param {engine.view.DocumentFragment|engine.view.Element} viewItem Part of the view to be converted.
  165. */
  166. /**
  167. * Fired when {@link engine.view.Element} is converted.
  168. *
  169. * `element` is a namespace event for a class of events. Names of actually called events follow this pattern:
  170. * `element:<elementName>` where `elementName` is the name of converted element. This way listeners may listen to
  171. * all elements conversion or to conversion of specific elements.
  172. *
  173. * @event engine.conversion.ViewConversionDispatcher.element
  174. * @param {Object} data Object containing conversion input and a placeholder for conversion output and possibly other
  175. * values (see {@link engine.conversion.ViewConversionDispatcher#convert}). Keep in mind that this object is shared
  176. * by reference between all callbacks that will be called. This means that callbacks can add their own values if needed,
  177. * and those values will be available in other callbacks.
  178. * @param {engine.view.Element} data.input Converted element.
  179. * @param {*} data.output The current state of conversion result. Every change to converted element should
  180. * be reflected by setting or modifying this property.
  181. * @param {engine.conversion.ViewConsumable} consumable Values to consume.
  182. * @param {Object} conversionApi Conversion interface to be used by callback, passed in `ViewConversionDispatcher` constructor.
  183. * Besides of properties passed in constructor, it also has `convertItem` and `convertChildren` methods which are references
  184. * to {@link engine.conversion.ViewConversionDispatcher#_convertItem} and
  185. * {@link engine.conversion.ViewConversionDispatcher#_convertChildren}. Those methods are needed to convert
  186. * the whole view-tree they were exposed in `conversionApi` for callbacks.
  187. */
  188. /**
  189. * Fired when {@link engine.view.Text} is converted.
  190. *
  191. * @event engine.conversion.ViewConversionDispatcher.text
  192. * @see engine.conversion.ViewConversionDispatcher.element
  193. */
  194. /**
  195. * Fired when {@link engine.view.DocumentFragment} is converted.
  196. *
  197. * @event engine.conversion.ViewConversionDispatcher.documentFragment
  198. * @see engine.conversion.ViewConversionDispatcher.element
  199. */
  200. }
  201. mix( ViewConversionDispatcher, EmitterMixin );
  202. /**
  203. * Conversion interface that is registered for given {@link engine.conversion.ViewConversionDispatcher} and is
  204. * passed as one of parameters when {@link engine.conversion.ViewConversionDispatcher dispatcher} fires it's events.
  205. *
  206. * `ViewConversionApi` object is built by {@link engine.conversion.ViewConversionDispatcher} constructor. The exact
  207. * list of properties of this object is determined by the object passed to the constructor.
  208. *
  209. * @interface engine.conversion.ViewConversionApi
  210. */
  211. /**
  212. * Starts conversion of given item by firing an appropriate event.
  213. *
  214. * Every fired event is passed (as first parameter) an object with `output` property. Every event may set and/or
  215. * modify that property. When all callbacks are done, the final value of `output` property is returned by this method.
  216. *
  217. * @memberOf engine.conversion.ViewConversionApi
  218. * @function covertItem
  219. * @fires engine.conversion.ViewConversionDispatcher.element
  220. * @fires engine.conversion.ViewConversionDispatcher.text
  221. * @fires engine.conversion.ViewConversionDispatcher.documentFragment
  222. * @param {engine.view.DocumentFragment|engine.view.Element|engine.view.Text} input Item to convert.
  223. * @param {engine.conversion.ViewConsumable} consumable Values to consume.
  224. * @param {Object} [additionalData] Additional data to be passed in `data` argument when firing `ViewConversionDispatcher`
  225. * events. See also {@link engine.conversion.ViewConversionDispatcher.element element event}.
  226. * @returns {*} The result of item conversion, created and modified by callbacks attached to fired event.
  227. */
  228. /**
  229. * Starts conversion of all children of given item by firing appropriate events for all those children.
  230. *
  231. * @memberOf engine.conversion.ViewConversionApi
  232. * @function convertChildren
  233. * @fires engine.conversion.ViewConversionDispatcher.element
  234. * @fires engine.conversion.ViewConversionDispatcher.text
  235. * @fires engine.conversion.ViewConversionDispatcher.documentFragment
  236. * @param {engine.view.DocumentFragment|engine.view.Element} input Item which children will be converted.
  237. * @param {engine.conversion.ViewConsumable} consumable Values to consume.
  238. * @param {Object} [additionalData] Additional data to be passed in `data` argument when firing `ViewConversionDispatcher`
  239. * events. See also {@link engine.conversion.ViewConversionDispatcher.element element event}.
  240. * @returns {Array.<*>} Array containing results of conversion of all children of given item.
  241. */