src/model/operation/mergeoperation.js
/**
* @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/
/**
* @module engine/model/operation/mergeoperation
*/
import Operation from './operation';
import SplitOperation from './splitoperation';
import Position from '../position';
import Range from '../range';
import { _move } from './utils';
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
/**
* Operation to merge two {@link module:engine/model/element~Element elements}.
*
* The merged element is the parent of {@link ~MergeOperation#sourcePosition} and it is merged into the parent of
* {@link ~MergeOperation#targetPosition}. All nodes from the merged element are moved to {@link ~MergeOperation#targetPosition}.
*
* The merged element is moved to the graveyard at {@link ~MergeOperation#graveyardPosition}.
*
* @extends module:engine/model/operation/operation~Operation
*/
export default class MergeOperation extends Operation {
/**
* Creates a merge operation.
*
* @param {module:engine/model/position~Position} sourcePosition Position inside the merged element. All nodes from that
* element after that position will be moved to {@link ~#targetPosition}.
* @param {Number} howMany Summary offset size of nodes which will be moved from the merged element to the new parent.
* @param {module:engine/model/position~Position} targetPosition Position which the nodes from the merged elements will be moved to.
* @param {module:engine/model/position~Position} graveyardPosition Position in graveyard to which the merged element will be moved.
* @param {Number|null} baseVersion Document {@link module:engine/model/document~Document#version} on which operation
* can be applied or `null` if the operation operates on detached (non-document) tree.
*/
constructor( sourcePosition, howMany, targetPosition, graveyardPosition, baseVersion ) {
super( baseVersion );
/**
* Position inside the merged element. All nodes from that element after that position will be moved to {@link ~#targetPosition}.
*
* @member {module:engine/model/position~Position} module:engine/model/operation/mergeoperation~MergeOperation#sourcePosition
*/
this.sourcePosition = sourcePosition.clone();
// This is, and should always remain, the first position in its parent.
this.sourcePosition.stickiness = 'toPrevious';
/**
* Summary offset size of nodes which will be moved from the merged element to the new parent.
*
* @member {Number} module:engine/model/operation/mergeoperation~MergeOperation#howMany
*/
this.howMany = howMany;
/**
* Position which the nodes from the merged elements will be moved to.
*
* @member {module:engine/model/position~Position} module:engine/model/operation/mergeoperation~MergeOperation#targetPosition
*/
this.targetPosition = targetPosition.clone();
// Except of a rare scenario in `MergeOperation` x `MergeOperation` transformation,
// this is, and should always remain, the last position in its parent.
this.targetPosition.stickiness = 'toNext';
/**
* Position in graveyard to which the merged element will be moved.
*
* @member {module:engine/model/position~Position} module:engine/model/operation/mergeoperation~MergeOperation#graveyardPosition
*/
this.graveyardPosition = graveyardPosition.clone();
}
/**
* @inheritDoc
*/
get type() {
return 'merge';
}
/**
* Position before the merged element (which will be deleted).
*
* @readonly
* @type {module:engine/model/position~Position}
*/
get deletionPosition() {
return new Position( this.sourcePosition.root, this.sourcePosition.path.slice( 0, -1 ) );
}
/**
* Artificial range that contains all the nodes from the merged element that will be moved to {@link ~MergeOperation#sourcePosition}.
* The range starts at {@link ~MergeOperation#sourcePosition} and ends in the same parent, at `POSITIVE_INFINITY` offset.
*
* @readonly
* @type {module:engine/model/range~Range}
*/
get movedRange() {
const end = this.sourcePosition.getShiftedBy( Number.POSITIVE_INFINITY );
return new Range( this.sourcePosition, end );
}
/**
* Creates and returns an operation that has the same parameters as this operation.
*
* @returns {module:engine/model/operation/mergeoperation~MergeOperation} Clone of this operation.
*/
clone() {
return new this.constructor( this.sourcePosition, this.howMany, this.targetPosition, this.graveyardPosition, this.baseVersion );
}
/**
* See {@link module:engine/model/operation/operation~Operation#getReversed `Operation#getReversed()`}.
*
* @returns {module:engine/model/operation/splitoperation~SplitOperation}
*/
getReversed() {
// Positions in this method are transformed by this merge operation because the split operation bases on
// the context after this merge operation happened (because split operation reverses it).
// So we need to acknowledge that the merge operation happened and those positions changed a little.
const targetPosition = this.targetPosition._getTransformedByMergeOperation( this );
const path = this.sourcePosition.path.slice( 0, -1 );
const insertionPosition = new Position( this.sourcePosition.root, path )._getTransformedByMergeOperation( this );
const split = new SplitOperation( targetPosition, this.howMany, this.graveyardPosition, this.baseVersion + 1 );
split.insertionPosition = insertionPosition;
return split;
}
/**
* @inheritDoc
*/
_validate() {
const sourceElement = this.sourcePosition.parent;
const targetElement = this.targetPosition.parent;
// Validate whether merge operation has correct parameters.
if ( !sourceElement.parent ) {
/**
* Merge source position is invalid. The element to be merged must have a parent node.
*
* @error merge-operation-source-position-invalid
*/
throw new CKEditorError( 'merge-operation-source-position-invalid: Merge source position is invalid.', this );
} else if ( !targetElement.parent ) {
/**
* Merge target position is invalid. The element to be merged must have a parent node.
*
* @error merge-operation-target-position-invalid
*/
throw new CKEditorError( 'merge-operation-target-position-invalid: Merge target position is invalid.', this );
} else if ( this.howMany != sourceElement.maxOffset ) {
/**
* Merge operation specifies wrong number of nodes to move.
*
* @error merge-operation-how-many-invalid
*/
throw new CKEditorError( 'merge-operation-how-many-invalid: Merge operation specifies wrong number of nodes to move.', this );
}
}
/**
* @inheritDoc
*/
_execute() {
const mergedElement = this.sourcePosition.parent;
const sourceRange = Range._createIn( mergedElement );
_move( sourceRange, this.targetPosition );
_move( Range._createOn( mergedElement ), this.graveyardPosition );
}
/**
* @inheritDoc
*/
toJSON() {
const json = super.toJSON();
json.sourcePosition = json.sourcePosition.toJSON();
json.targetPosition = json.targetPosition.toJSON();
json.graveyardPosition = json.graveyardPosition.toJSON();
return json;
}
/**
* @inheritDoc
*/
static get className() {
return 'MergeOperation';
}
/**
* Creates `MergeOperation` object from deserilized object, i.e. from parsed JSON string.
*
* @param {Object} json Deserialized JSON object.
* @param {module:engine/model/document~Document} document Document on which this operation will be applied.
* @returns {module:engine/model/operation/mergeoperation~MergeOperation}
*/
static fromJSON( json, document ) {
const sourcePosition = Position.fromJSON( json.sourcePosition, document );
const targetPosition = Position.fromJSON( json.targetPosition, document );
const graveyardPosition = Position.fromJSON( json.graveyardPosition, document );
return new this( sourcePosition, json.howMany, targetPosition, graveyardPosition, json.baseVersion );
}
// @if CK_DEBUG_ENGINE // toString() {
// @if CK_DEBUG_ENGINE // return `MergeOperation( ${ this.baseVersion } ): ` +
// @if CK_DEBUG_ENGINE // `${ this.sourcePosition } -> ${ this.targetPosition }` +
// @if CK_DEBUG_ENGINE // ` ( ${ this.howMany } ), ${ this.graveyardPosition }`;
// @if CK_DEBUG_ENGINE // }
}