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- /**
- * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md.
- */
- /**
- * @module engine/conversion/mapper
- */
- import ModelPosition from '../model/position';
- import ModelRange from '../model/range';
- import ViewPosition from '../view/position';
- import ViewRange from '../view/range';
- import ViewText from '../view/text';
- import EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';
- import mix from '@ckeditor/ckeditor5-utils/src/mix';
- /**
- * Maps elements, positions and markers between {@link module:engine/view/document~Document the view} and
- * {@link module:engine/model/model the model}.
- *
- * Mapper use bound elements to find corresponding elements and positions, so, to get proper results,
- * all model elements should be {@link module:engine/conversion/mapper~Mapper#bindElements bound}.
- *
- * To map complex model to/from view relations, you may provide custom callbacks for
- * {@link module:engine/conversion/mapper~Mapper#event:modelToViewPosition modelToViewPosition event} and
- * {@link module:engine/conversion/mapper~Mapper#event:viewToModelPosition viewToModelPosition event} that are fired whenever
- * a position mapping request occurs.
- * Those events are fired by {@link module:engine/conversion/mapper~Mapper#toViewPosition toViewPosition}
- * and {@link module:engine/conversion/mapper~Mapper#toModelPosition toModelPosition} methods. `Mapper` adds it's own default callbacks
- * with `'lowest'` priority. To override default `Mapper` mapping, add custom callback with higher priority and
- * stop the event.
- */
- export default class Mapper {
- /**
- * Creates an instance of the mapper.
- */
- constructor() {
- /**
- * Model element to view element mapping.
- *
- * @private
- * @member {WeakMap}
- */
- this._modelToViewMapping = new WeakMap();
- /**
- * View element to model element mapping.
- *
- * @private
- * @member {WeakMap}
- */
- this._viewToModelMapping = new WeakMap();
- /**
- * A map containing callbacks between view element names and functions evaluating length of view elements
- * in model.
- *
- * @private
- * @member {Map}
- */
- this._viewToModelLengthCallbacks = new Map();
- /**
- * Model marker name to view elements mapping.
- *
- * Keys are `String`s while values are `Set`s with {@link module:engine/view/element~Element view elements}.
- * One marker (name) can be mapped to multiple elements.
- *
- * @private
- * @member {Map}
- */
- this._markerNameToElements = new Map();
- // Default mapper algorithm for mapping model position to view position.
- this.on( 'modelToViewPosition', ( evt, data ) => {
- if ( data.viewPosition ) {
- return;
- }
- const viewContainer = this._modelToViewMapping.get( data.modelPosition.parent );
- data.viewPosition = this._findPositionIn( viewContainer, data.modelPosition.offset );
- }, { priority: 'low' } );
- // Default mapper algorithm for mapping view position to model position.
- this.on( 'viewToModelPosition', ( evt, data ) => {
- if ( data.modelPosition ) {
- return;
- }
- const viewBlock = this.findMappedViewAncestor( data.viewPosition );
- const modelParent = this._viewToModelMapping.get( viewBlock );
- const modelOffset = this._toModelOffset( data.viewPosition.parent, data.viewPosition.offset, viewBlock );
- data.modelPosition = ModelPosition._createAt( modelParent, modelOffset );
- }, { priority: 'low' } );
- }
- /**
- * Marks model and view elements as corresponding. Corresponding elements can be retrieved by using
- * the {@link module:engine/conversion/mapper~Mapper#toModelElement toModelElement} and
- * {@link module:engine/conversion/mapper~Mapper#toViewElement toViewElement} methods.
- * The information that elements are bound is also used to translate positions.
- *
- * @param {module:engine/model/element~Element} modelElement Model element.
- * @param {module:engine/view/element~Element} viewElement View element.
- */
- bindElements( modelElement, viewElement ) {
- this._modelToViewMapping.set( modelElement, viewElement );
- this._viewToModelMapping.set( viewElement, modelElement );
- }
- /**
- * Unbinds given {@link module:engine/view/element~Element view element} from the map.
- *
- * **Note:** view-to-model binding will be removed, if it existed. However, corresponding model-to-view binding
- * will be removed only if model element is still bound to passed `viewElement`.
- *
- * This behavior lets for re-binding model element to another view element without fear of losing the new binding
- * when the previously bound view element is unbound.
- *
- * @param {module:engine/view/element~Element} viewElement View element to unbind.
- */
- unbindViewElement( viewElement ) {
- const modelElement = this.toModelElement( viewElement );
- this._viewToModelMapping.delete( viewElement );
- if ( this._modelToViewMapping.get( modelElement ) == viewElement ) {
- this._modelToViewMapping.delete( modelElement );
- }
- }
- /**
- * Unbinds given {@link module:engine/model/element~Element model element} from the map.
- *
- * **Note:** model-to-view binding will be removed, if it existed. However, corresponding view-to-model binding
- * will be removed only if view element is still bound to passed `modelElement`.
- *
- * This behavior lets for re-binding view element to another model element without fear of losing the new binding
- * when the previously bound model element is unbound.
- *
- * @param {module:engine/model/element~Element} modelElement Model element to unbind.
- */
- unbindModelElement( modelElement ) {
- const viewElement = this.toViewElement( modelElement );
- this._modelToViewMapping.delete( modelElement );
- if ( this._viewToModelMapping.get( viewElement ) == modelElement ) {
- this._viewToModelMapping.delete( viewElement );
- }
- }
- /**
- * Binds given marker name with given {@link module:engine/view/element~Element view element}. The element
- * will be added to the current set of elements bound with given marker name.
- *
- * @param {module:engine/view/element~Element} element Element to bind.
- * @param {String} name Marker name.
- */
- bindElementToMarker( element, name ) {
- const elements = this._markerNameToElements.get( name ) || new Set();
- elements.add( element );
- this._markerNameToElements.set( name, elements );
- }
- /**
- * Unbinds all elements from given marker name.
- *
- * @param {String} name Marker name.
- */
- unbindElementsFromMarkerName( name ) {
- this._markerNameToElements.delete( name );
- }
- /**
- * Removes all model to view and view to model bindings.
- */
- clearBindings() {
- this._modelToViewMapping = new WeakMap();
- this._viewToModelMapping = new WeakMap();
- this._markerNameToElements = new Map();
- }
- /**
- * Gets the corresponding model element.
- *
- * **Note:** {@link module:engine/view/uielement~UIElement} does not have corresponding element in model.
- *
- * @param {module:engine/view/element~Element} viewElement View element.
- * @returns {module:engine/model/element~Element|undefined} Corresponding model element or `undefined` if not found.
- */
- toModelElement( viewElement ) {
- return this._viewToModelMapping.get( viewElement );
- }
- /**
- * Gets the corresponding view element.
- *
- * @param {module:engine/model/element~Element} modelElement Model element.
- * @returns {module:engine/view/element~Element|undefined} Corresponding view element or `undefined` if not found.
- */
- toViewElement( modelElement ) {
- return this._modelToViewMapping.get( modelElement );
- }
- /**
- * Gets the corresponding model range.
- *
- * @param {module:engine/view/range~Range} viewRange View range.
- * @returns {module:engine/model/range~Range} Corresponding model range.
- */
- toModelRange( viewRange ) {
- return new ModelRange( this.toModelPosition( viewRange.start ), this.toModelPosition( viewRange.end ) );
- }
- /**
- * Gets the corresponding view range.
- *
- * @param {module:engine/model/range~Range} modelRange Model range.
- * @returns {module:engine/view/range~Range} Corresponding view range.
- */
- toViewRange( modelRange ) {
- return new ViewRange( this.toViewPosition( modelRange.start ), this.toViewPosition( modelRange.end ) );
- }
- /**
- * Gets the corresponding model position.
- *
- * @fires viewToModelPosition
- * @param {module:engine/view/position~Position} viewPosition View position.
- * @returns {module:engine/model/position~Position} Corresponding model position.
- */
- toModelPosition( viewPosition ) {
- const data = {
- viewPosition,
- mapper: this
- };
- this.fire( 'viewToModelPosition', data );
- return data.modelPosition;
- }
- /**
- * Gets the corresponding view position.
- *
- * @fires modelToViewPosition
- * @param {module:engine/model/position~Position} modelPosition Model position.
- * @param {Object} [options] Additional options for position mapping process.
- * @param {Boolean} [options.isPhantom=false] Should be set to `true` if the model position to map is pointing to a place
- * in model tree which no longer exists. For example, it could be an end of a removed model range.
- * @returns {module:engine/view/position~Position} Corresponding view position.
- */
- toViewPosition( modelPosition, options = { isPhantom: false } ) {
- const data = {
- modelPosition,
- mapper: this,
- isPhantom: options.isPhantom
- };
- this.fire( 'modelToViewPosition', data );
- return data.viewPosition;
- }
- /**
- * Gets all view elements bound to the given marker name.
- *
- * @param {String} name Marker name.
- * @returns {Set.<module:engine/view/element~Element>|null} View elements bound with given marker name or `null`
- * if no elements are bound to given marker name.
- */
- markerNameToElements( name ) {
- const boundElements = this._markerNameToElements.get( name );
- if ( !boundElements ) {
- return null;
- }
- const elements = new Set();
- for ( const element of boundElements ) {
- if ( element.is( 'attributeElement' ) ) {
- for ( const clone of element.getElementsWithSameId() ) {
- elements.add( clone );
- }
- } else {
- elements.add( element );
- }
- }
- return elements;
- }
- /**
- * Registers a callback that evaluates the length in the model of a view element with given name.
- *
- * The callback is fired with one argument, which is a view element instance. The callback is expected to return
- * a number representing the length of view element in model.
- *
- * // List item in view may contain nested list, which have other list items. In model though,
- * // the lists are represented by flat structure. Because of those differences, length of list view element
- * // may be greater than one. In the callback it's checked how many nested list items are in evaluated list item.
- *
- * function getViewListItemLength( element ) {
- * let length = 1;
- *
- * for ( let child of element.getChildren() ) {
- * if ( child.name == 'ul' || child.name == 'ol' ) {
- * for ( let item of child.getChildren() ) {
- * length += getViewListItemLength( item );
- * }
- * }
- * }
- *
- * return length;
- * }
- *
- * mapper.registerViewToModelLength( 'li', getViewListItemLength );
- *
- * @param {String} viewElementName Name of view element for which callback is registered.
- * @param {Function} lengthCallback Function return a length of view element instance in model.
- */
- registerViewToModelLength( viewElementName, lengthCallback ) {
- this._viewToModelLengthCallbacks.set( viewElementName, lengthCallback );
- }
- /**
- * For given `viewPosition`, finds and returns the closest ancestor of this position that has a mapping to
- * the model.
- *
- * @param {module:engine/view/position~Position} viewPosition Position for which mapped ancestor should be found.
- * @returns {module:engine/view/element~Element}
- */
- findMappedViewAncestor( viewPosition ) {
- let parent = viewPosition.parent;
- while ( !this._viewToModelMapping.has( parent ) ) {
- parent = parent.parent;
- }
- return parent;
- }
- /**
- * Calculates model offset based on the view position and the block element.
- *
- * Example:
- *
- * <p>foo<b>ba|r</b></p> // _toModelOffset( b, 2, p ) -> 5
- *
- * Is a sum of:
- *
- * <p>foo|<b>bar</b></p> // _toModelOffset( p, 3, p ) -> 3
- * <p>foo<b>ba|r</b></p> // _toModelOffset( b, 2, b ) -> 2
- *
- * @private
- * @param {module:engine/view/element~Element} viewParent Position parent.
- * @param {Number} viewOffset Position offset.
- * @param {module:engine/view/element~Element} viewBlock Block used as a base to calculate offset.
- * @returns {Number} Offset in the model.
- */
- _toModelOffset( viewParent, viewOffset, viewBlock ) {
- if ( viewBlock != viewParent ) {
- // See example.
- const offsetToParentStart = this._toModelOffset( viewParent.parent, viewParent.index, viewBlock );
- const offsetInParent = this._toModelOffset( viewParent, viewOffset, viewParent );
- return offsetToParentStart + offsetInParent;
- }
- // viewBlock == viewParent, so we need to calculate the offset in the parent element.
- // If the position is a text it is simple ("ba|r" -> 2).
- if ( viewParent.is( 'text' ) ) {
- return viewOffset;
- }
- // If the position is in an element we need to sum lengths of siblings ( <b> bar </b> foo | -> 3 + 3 = 6 ).
- let modelOffset = 0;
- for ( let i = 0; i < viewOffset; i++ ) {
- modelOffset += this.getModelLength( viewParent.getChild( i ) );
- }
- return modelOffset;
- }
- /**
- * Gets the length of the view element in the model.
- *
- * The length is calculated as follows:
- * * if {@link #registerViewToModelLength length mapping callback} is provided for given `viewNode` it is used to
- * evaluate model length (`viewNode` is used as first and only parameter passed to the callback),
- * * length of a {@link module:engine/view/text~Text text node} is equal to the length of it's
- * {@link module:engine/view/text~Text#data data},
- * * length of a {@link module:engine/view/uielement~UIElement ui element} is equal to 0,
- * * length of a mapped {@link module:engine/view/element~Element element} is equal to 1,
- * * length of a not-mapped {@link module:engine/view/element~Element element} is equal to the length of it's children.
- *
- * Examples:
- *
- * foo -> 3 // Text length is equal to it's data length.
- * <p>foo</p> -> 1 // Length of an element which is mapped is by default equal to 1.
- * <b>foo</b> -> 3 // Length of an element which is not mapped is a length of its children.
- * <div><p>x</p><p>y</p></div> -> 2 // Assuming that <div> is not mapped and <p> are mapped.
- *
- * @param {module:engine/view/element~Element} viewNode View node.
- * @returns {Number} Length of the node in the tree model.
- */
- getModelLength( viewNode ) {
- if ( this._viewToModelLengthCallbacks.get( viewNode.name ) ) {
- const callback = this._viewToModelLengthCallbacks.get( viewNode.name );
- return callback( viewNode );
- } else if ( this._viewToModelMapping.has( viewNode ) ) {
- return 1;
- } else if ( viewNode.is( 'text' ) ) {
- return viewNode.data.length;
- } else if ( viewNode.is( 'uiElement' ) ) {
- return 0;
- } else {
- let len = 0;
- for ( const child of viewNode.getChildren() ) {
- len += this.getModelLength( child );
- }
- return len;
- }
- }
- /**
- * Finds the position in the view node (or its children) with the expected model offset.
- *
- * Example:
- *
- * <p>fo<b>bar</b>bom</p> -> expected offset: 4
- *
- * _findPositionIn( p, 4 ):
- * <p>|fo<b>bar</b>bom</p> -> expected offset: 4, actual offset: 0
- * <p>fo|<b>bar</b>bom</p> -> expected offset: 4, actual offset: 2
- * <p>fo<b>bar</b>|bom</p> -> expected offset: 4, actual offset: 5 -> we are too far
- *
- * _findPositionIn( b, 4 - ( 5 - 3 ) ):
- * <p>fo<b>|bar</b>bom</p> -> expected offset: 2, actual offset: 0
- * <p>fo<b>bar|</b>bom</p> -> expected offset: 2, actual offset: 3 -> we are too far
- *
- * _findPositionIn( bar, 2 - ( 3 - 3 ) ):
- * We are in the text node so we can simple find the offset.
- * <p>fo<b>ba|r</b>bom</p> -> expected offset: 2, actual offset: 2 -> position found
- *
- * @private
- * @param {module:engine/view/element~Element} viewParent Tree view element in which we are looking for the position.
- * @param {Number} expectedOffset Expected offset.
- * @returns {module:engine/view/position~Position} Found position.
- */
- _findPositionIn( viewParent, expectedOffset ) {
- // Last scanned view node.
- let viewNode;
- // Length of the last scanned view node.
- let lastLength = 0;
- let modelOffset = 0;
- let viewOffset = 0;
- // In the text node it is simple: offset in the model equals offset in the text.
- if ( viewParent.is( 'text' ) ) {
- return new ViewPosition( viewParent, expectedOffset );
- }
- // In other cases we add lengths of child nodes to find the proper offset.
- // If it is smaller we add the length.
- while ( modelOffset < expectedOffset ) {
- viewNode = viewParent.getChild( viewOffset );
- lastLength = this.getModelLength( viewNode );
- modelOffset += lastLength;
- viewOffset++;
- }
- // If it equals we found the position.
- if ( modelOffset == expectedOffset ) {
- return this._moveViewPositionToTextNode( new ViewPosition( viewParent, viewOffset ) );
- }
- // If it is higher we need to enter last child.
- else {
- // ( modelOffset - lastLength ) is the offset to the child we enter,
- // so we subtract it from the expected offset to fine the offset in the child.
- return this._findPositionIn( viewNode, expectedOffset - ( modelOffset - lastLength ) );
- }
- }
- /**
- * Because we prefer positions in text nodes over positions next to text node moves view position to the text node
- * if it was next to it.
- *
- * <p>[]<b>foo</b></p> -> <p>[]<b>foo</b></p> // do not touch if position is not directly next to text
- * <p>foo[]<b>foo</b></p> -> <p>foo{}<b>foo</b></p> // move to text node
- * <p><b>[]foo</b></p> -> <p><b>{}foo</b></p> // move to text node
- *
- * @private
- * @param {module:engine/view/position~Position} viewPosition Position potentially next to text node.
- * @returns {module:engine/view/position~Position} Position in text node if possible.
- */
- _moveViewPositionToTextNode( viewPosition ) {
- // If the position is just after text node, put it at the end of that text node.
- // If the position is just before text node, put it at the beginning of that text node.
- const nodeBefore = viewPosition.nodeBefore;
- const nodeAfter = viewPosition.nodeAfter;
- if ( nodeBefore instanceof ViewText ) {
- return new ViewPosition( nodeBefore, nodeBefore.data.length );
- } else if ( nodeAfter instanceof ViewText ) {
- return new ViewPosition( nodeAfter, 0 );
- }
- // Otherwise, just return the given position.
- return viewPosition;
- }
- /**
- * Fired for each model-to-view position mapping request. The purpose of this event is to enable custom model-to-view position
- * mapping. Callbacks added to this event take {@link module:engine/model/position~Position model position} and are expected to
- * calculate {@link module:engine/view/position~Position view position}. Calculated view position should be added as `viewPosition`
- * value in `data` object that is passed as one of parameters to the event callback.
- *
- * // Assume that "captionedImage" model element is converted to <img> and following <span> elements in view,
- * // and the model element is bound to <img> element. Force mapping model positions inside "captionedImage" to that
- * // <span> element.
- * mapper.on( 'modelToViewPosition', ( evt, data ) => {
- * const positionParent = modelPosition.parent;
- *
- * if ( positionParent.name == 'captionedImage' ) {
- * const viewImg = data.mapper.toViewElement( positionParent );
- * const viewCaption = viewImg.nextSibling; // The <span> element.
- *
- * data.viewPosition = new ViewPosition( viewCaption, modelPosition.offset );
- *
- * // Stop the event if other callbacks should not modify calculated value.
- * evt.stop();
- * }
- * } );
- *
- * **Note:** keep in mind that sometimes a "phantom" model position is being converted. "Phantom" model position is
- * a position that points to a non-existing place in model. Such position might still be valid for conversion, though
- * (it would point to a correct place in view when converted). One example of such situation is when a range is
- * removed from model, there may be a need to map the range's end (which is no longer valid model position). To
- * handle such situation, check `data.isPhantom` flag:
- *
- * // Assume that there is "customElement" model element and whenever position is before it, we want to move it
- * // to the inside of the view element bound to "customElement".
- * mapper.on( 'modelToViewPosition', ( evt, data ) => {
- * if ( data.isPhantom ) {
- * return;
- * }
- *
- * // Below line might crash for phantom position that does not exist in model.
- * const sibling = data.modelPosition.nodeBefore;
- *
- * // Check if this is the element we are interested in.
- * if ( !sibling.is( 'customElement' ) ) {
- * return;
- * }
- *
- * const viewElement = data.mapper.toViewElement( sibling );
- *
- * data.viewPosition = new ViewPosition( sibling, 0 );
- *
- * evt.stop();
- * } );
- *
- * **Note:** default mapping callback is provided with `low` priority setting and does not cancel the event, so it is possible to
- * attach a custom callback after default callback and also use `data.viewPosition` calculated by default callback
- * (for example to fix it).
- *
- * **Note:** default mapping callback will not fire if `data.viewPosition` is already set.
- *
- * **Note:** these callbacks are called **very often**. For efficiency reasons, it is advised to use them only when position
- * mapping between given model and view elements is unsolvable using just elements mapping and default algorithm. Also,
- * the condition that checks if special case scenario happened should be as simple as possible.
- *
- * @event modelToViewPosition
- * @param {Object} data Data pipeline object that can store and pass data between callbacks. The callback should add
- * `viewPosition` value to that object with calculated {@link module:engine/view/position~Position view position}.
- * @param {module:engine/conversion/mapper~Mapper} data.mapper Mapper instance that fired the event.
- */
- /**
- * Fired for each view-to-model position mapping request. See {@link module:engine/conversion/mapper~Mapper#event:modelToViewPosition}.
- *
- * // See example in `modelToViewPosition` event description.
- * // This custom mapping will map positions from <span> element next to <img> to the "captionedImage" element.
- * mapper.on( 'viewToModelPosition', ( evt, data ) => {
- * const positionParent = viewPosition.parent;
- *
- * if ( positionParent.hasClass( 'image-caption' ) ) {
- * const viewImg = positionParent.previousSibling;
- * const modelImg = data.mapper.toModelElement( viewImg );
- *
- * data.modelPosition = new ModelPosition( modelImg, viewPosition.offset );
- * evt.stop();
- * }
- * } );
- *
- * **Note:** default mapping callback is provided with `low` priority setting and does not cancel the event, so it is possible to
- * attach a custom callback after default callback and also use `data.modelPosition` calculated by default callback
- * (for example to fix it).
- *
- * **Note:** default mapping callback will not fire if `data.modelPosition` is already set.
- *
- * **Note:** these callbacks are called **very often**. For efficiency reasons, it is advised to use them only when position
- * mapping between given model and view elements is unsolvable using just elements mapping and default algorithm. Also,
- * the condition that checks if special case scenario happened should be as simple as possible.
- *
- * @event viewToModelPosition
- * @param {Object} data Data pipeline object that can store and pass data between callbacks. The callback should add
- * `modelPosition` value to that object with calculated {@link module:engine/model/position~Position model position}.
- * @param {module:engine/conversion/mapper~Mapper} data.mapper Mapper instance that fired the event.
- */
- }
- mix( Mapper, EmitterMixin );
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