ckeditor/ckeditor5-engine

/**
 * @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/rootattributeoperation
 */

import Operation from './operation';
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';

/**
 * Operation to change root element's attribute. Using this class you can add, remove or change value of the attribute.
 *
 * This operation is needed, because root elements can't be changed through
 * @link module:engine/model/operation/attributeoperation~AttributeOperation}.
 * It is because {@link module:engine/model/operation/attributeoperation~AttributeOperation}
 * requires a range to change and root element can't
 * be a part of range because every {@link module:engine/model/position~Position} has to be inside a root.
 * {@link module:engine/model/position~Position} can't be created before a root element.
 *
 * @extends module:engine/model/operation/operation~Operation
 */
export default class RootAttributeOperation extends Operation {
    /**
     * Creates an operation that changes, removes or adds attributes on root element.
     *
     * @see module:engine/model/operation/attributeoperation~AttributeOperation
     * @param {module:engine/model/rootelement~RootElement} root Root element to change.
     * @param {String} key Key of an attribute to change or remove.
     * @param {*} oldValue Old value of the attribute with given key or `null` if adding a new attribute.
     * @param {*} newValue New value to set for the attribute. If `null`, then the operation just removes the attribute.
     * @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( root, key, oldValue, newValue, baseVersion ) {
        super( baseVersion );

        /**
         * Root element to change.
         *
         * @readonly
         * @member {module:engine/model/rootelement~RootElement}
         */
        this.root = root;

        /**
         * Key of an attribute to change or remove.
         *
         * @readonly
         * @member {String}
         */
        this.key = key;

        /**
         * Old value of the attribute with given key or `null` if adding a new attribute.
         *
         * @readonly
         * @member {*}
         */
        this.oldValue = oldValue;

        /**
         * New value to set for the attribute. If `null`, then the operation just removes the attribute.
         *
         * @readonly
         * @member {*}
         */
        this.newValue = newValue;
    }

    /**
     * @inheritDoc
     */
    get type() {
        if ( this.oldValue === null ) {
            return 'addRootAttribute';
        } else if ( this.newValue === null ) {
            return 'removeRootAttribute';
        } else {
            return 'changeRootAttribute';
        }
    }

    /**
     * Creates and returns an operation that has the same parameters as this operation.
     *
     * @returns {module:engine/model/operation/rootattributeoperation~RootAttributeOperation} Clone of this operation.
     */
    clone() {
        return new RootAttributeOperation( this.root, this.key, this.oldValue, this.newValue, this.baseVersion );
    }

    /**
     * See {@link module:engine/model/operation/operation~Operation#getReversed `Operation#getReversed()`}.
     *
     * @returns {module:engine/model/operation/rootattributeoperation~RootAttributeOperation}
     */
    getReversed() {
        return new RootAttributeOperation( this.root, this.key, this.newValue, this.oldValue, this.baseVersion + 1 );
    }

    /**
     * @inheritDoc
     */
    _validate() {
        if ( this.root != this.root.root || this.root.is( 'documentFragment' ) ) {
            /**
             * The element to change is not a root element.
             *
             * @error rootattribute-operation-not-a-root
             * @param {module:engine/model/rootelement~RootElement} root
             * @param {String} key
             * @param {*} value
             */
            throw new CKEditorError(
                'rootattribute-operation-not-a-root: The element to change is not a root element.',
                this,
                { root: this.root, key: this.key }
            );
        }

        if ( this.oldValue !== null && this.root.getAttribute( this.key ) !== this.oldValue ) {
            /**
             * The attribute which should be removed does not exists for the given node.
             *
             * @error rootattribute-operation-wrong-old-value
             * @param {module:engine/model/rootelement~RootElement} root
             * @param {String} key
             * @param {*} value
             */
            throw new CKEditorError(
                'rootattribute-operation-wrong-old-value: Changed node has different attribute value than operation\'s ' +
                'old attribute value.',
                this,
                { root: this.root, key: this.key }
            );
        }

        if ( this.oldValue === null && this.newValue !== null && this.root.hasAttribute( this.key ) ) {
            /**
             * The attribute with given key already exists for the given node.
             *
             * @error rootattribute-operation-attribute-exists
             * @param {module:engine/model/rootelement~RootElement} root
             * @param {String} key
             */
            throw new CKEditorError(
                'rootattribute-operation-attribute-exists: The attribute with given key already exists.',
                this,
                { root: this.root, key: this.key }
            );
        }
    }

    /**
     * @inheritDoc
     */
    _execute() {
        if ( this.newValue !== null ) {
            this.root._setAttribute( this.key, this.newValue );
        } else {
            this.root._removeAttribute( this.key );
        }
    }

    /**
     * @inheritDoc
     */
    toJSON() {
        const json = super.toJSON();

        json.root = this.root.toJSON();

        return json;
    }

    /**
     * @inheritDoc
     */
    static get className() {
        return 'RootAttributeOperation';
    }

    /**
     * Creates RootAttributeOperation 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/rootattributeoperation~RootAttributeOperation}
     */
    static fromJSON( json, document ) {
        if ( !document.getRoot( json.root ) ) {
            /**
             * Cannot create RootAttributeOperation for document. Root with specified name does not exist.
             *
             * @error rootattributeoperation-fromjson-no-root
             * @param {String} rootName
             */
            throw new CKEditorError(
                'rootattribute-operation-fromjson-no-root: Cannot create RootAttributeOperation. Root with specified name does not exist.',
                this,
                { rootName: json.root }
            );
        }

        return new RootAttributeOperation( document.getRoot( json.root ), json.key, json.oldValue, json.newValue, json.baseVersion );
    }

    // @if CK_DEBUG_ENGINE // toString() {
    // @if CK_DEBUG_ENGINE //     return `RootAttributeOperation( ${ this.baseVersion } ): ` +
    // @if CK_DEBUG_ENGINE //        `"${ this.key }": ${ JSON.stringify( this.oldValue ) }` +
    // @if CK_DEBUG_ENGINE //        ` -> ${ JSON.stringify( this.newValue ) }, ${ this.root.rootName }`;
    // @if CK_DEBUG_ENGINE // }
}