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- /**
- * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md.
- */
- 'use strict';
- import Element from './element.js';
- import Text from './text.js';
- import TextProxy from './textproxy.js';
- import Position from './position.js';
- import CKEditorError from '../../utils/ckeditorerror.js';
- /**
- * Position iterator class. It allows to iterate forward and backward over the document.
- *
- * @memberOf engine.view
- */
- export default class TreeWalker {
- /**
- * Creates a range iterator. All parameters are optional, but you have to specify either `boundaries` or `startPosition`.
- *
- * @constructor
- * @param {Object} options Object with configuration.
- * @param {engine.view.Range} [options.boundaries=null] Range to define boundaries of the iterator.
- * @param {engine.view.Position} [options.startPosition] Starting position.
- * @param {'FORWARD'|'BACKWARD'} [options.direction='FORWARD'] Walking direction.
- * @param {Boolean} [options.singleCharacters=false] Flag indicating whether all characters from
- * {@link engine.view.Text} should be returned as one {@link engine.view.Text} (`false`) ore one by one as
- * {@link engine.view.TextProxy} (`true`).
- * @param {Boolean} [options.shallow=false] Flag indicating whether iterator should enter elements or not. If the
- * iterator is shallow child nodes of any iterated node will not be returned along with `ELEMENT_END` tag.
- * @param {Boolean} [options.ignoreElementEnd=false] Flag indicating whether iterator should ignore `ELEMENT_END`
- * tags. If the option is true walker will not return a parent node of start position. If this option is `true`
- * each {@link engine.view.Element} will be returned once, while if the option is `false` they might be returned
- * twice: for `'ELEMENT_START'` and `'ELEMENT_END'`.
- */
- constructor( options = {} ) {
- if ( !options.boundaries && !options.startPosition ) {
- /**
- * Neither boundaries nor starting position have been defined.
- *
- * @error tree-walker-no-start-position
- */
- throw new CKEditorError( 'tree-walker-no-start-position: Neither boundaries nor starting position have been defined.' );
- }
- if ( options.direction && options.direction != 'FORWARD' && options.direction != 'BACKWARD' ) {
- throw new CKEditorError(
- 'tree-walker-unknown-direction: Only `BACKWARD` and `FORWARD` direction allowed.',
- { direction: options.direction }
- );
- }
- /**
- * Iterator boundaries.
- *
- * When the iterator is walking `FORWARD` on the end of boundary or is walking `BACKWARD`
- * on the start of boundary, then `{ done: true }` is returned.
- *
- * If boundaries are not defined they are set before first and after last child of the root node.
- *
- * @readonly
- * @member {engine.view.Range} engine.view.TreeWalker#boundaries
- */
- this.boundaries = options.boundaries || null;
- /**
- * Iterator position. If start position is not defined then position depends on {@link #direction}. If direction is
- * `FORWARD` position starts form the beginning, when direction is `BACKWARD` position starts from the end.
- *
- * @readonly
- * @member {engine.view.Position} engine.view.TreeWalker#position
- */
- if ( options.startPosition ) {
- this.position = Position.createFromPosition( options.startPosition );
- } else {
- this.position = Position.createFromPosition( options.boundaries[ options.direction == 'BACKWARD' ? 'end' : 'start' ] );
- }
- /**
- * Walking direction. Defaults `FORWARD`.
- *
- * @readonly
- * @member {'BACKWARD'|'FORWARD'} engine.view.TreeWalker#direction
- */
- this.direction = options.direction || 'FORWARD';
- /**
- * Flag indicating whether all characters from {@link engine.view.Text} should be returned as one
- * {@link engine.view.Text} or one by one as {@link.engine.TextProxy}.
- *
- * @readonly
- * @member {Boolean} engine.view.TreeWalker#singleCharacters
- */
- this.singleCharacters = !!options.singleCharacters;
- /**
- * Flag indicating whether iterator should enter elements or not. If the iterator is shallow child nodes of any
- * iterated node will not be returned along with `ELEMENT_END` tag.
- *
- * @readonly
- * @member {Boolean} engine.view.TreeWalker#shallow
- */
- this.shallow = !!options.shallow;
- /**
- * Flag indicating whether iterator should ignore `ELEMENT_END` tags. If the option is true walker will not
- * return a parent node of the start position. If this option is `true` each {@link engine.view.Element} will
- * be returned once, while if the option is `false` they might be returned twice:
- * for `'ELEMENT_START'` and `'ELEMENT_END'`.
- *
- * @readonly
- * @member {Boolean} engine.view.TreeWalker#ignoreElementEnd
- */
- this.ignoreElementEnd = !!options.ignoreElementEnd;
- /**
- * Start boundary cached for optimization purposes.
- *
- * @private
- * @member {engine.view.Element} engine.view.TreeWalker#_boundaryStartParent
- */
- this._boundaryStartParent = this.boundaries ? this.boundaries.start.parent : null;
- /**
- * End boundary cached for optimization purposes.
- *
- * @private
- * @member {engine.view.Element} engine.view.TreeWalker#_boundaryEndParent
- */
- this._boundaryEndParent = this.boundaries ? this.boundaries.end.parent : null;
- }
- /**
- * Iterator interface.
- */
- [ Symbol.iterator ]() {
- return this;
- }
- /**
- * Iterator interface method.
- * Detects walking direction and makes step forward or backward.
- *
- * @returns {Object} Object implementing iterator interface, returning information about taken step.
- */
- next() {
- if ( this.direction == 'FORWARD' ) {
- return this._next();
- } else {
- return this._previous();
- }
- }
- /**
- * Makes a step forward in view. Moves the {@link #position} to the next position and returns the encountered value.
- *
- * @private
- * @returns {Object}
- * @returns {Boolean} return.done True if iterator is done.
- * @returns {engine.view.TreeWalkerValue} return.value Information about taken step.
- */
- _next() {
- let position = Position.createFromPosition( this.position );
- const previousPosition = this.position;
- const parent = position.parent;
- // We are at the end of the root.
- if ( parent.parent === null && position.offset === parent.getChildCount() ) {
- return { done: true };
- }
- // We reached the walker boundary.
- if ( parent === this._boundaryEndParent && position.offset == this.boundaries.end.offset ) {
- return { done: true };
- }
- // Get node just after current position.
- let node;
- // Text {@link engine.view.Text} element is a specific parent because it contains string instead of child nodes.
- if ( parent instanceof Text ) {
- node = parent._data[ position.offset ];
- } else {
- node = parent.getChild( position.offset );
- }
- if ( node instanceof Element ) {
- if ( !this.shallow ) {
- position = new Position( node, 0 );
- } else {
- position.offset++;
- }
- this.position = position;
- return formatReturnValue( 'ELEMENT_START', node, previousPosition, position, 1 );
- } else if ( node instanceof Text ) {
- if ( this.singleCharacters ) {
- position = new Position( node, 0 );
- this.position = position;
- return this._next();
- } else {
- let charactersCount = node._data.length;
- let item = node;
- // If text stick out of walker range, we need to cut it.
- if ( node == this._boundaryEndParent ) {
- const offset = this.boundaries.end.offset;
- const textFragment = node._data.substring( 0, offset );
- charactersCount = textFragment.length;
- item = new TextProxy( textFragment, node.parent, node, 0 );
- position = Position.createAfter( item );
- } else {
- // If not just move forward.
- position.offset++;
- }
- this.position = position;
- return formatReturnValue( 'TEXT', item, previousPosition, position, charactersCount );
- }
- } else if ( typeof node == 'string' ) {
- position.offset++;
- const textProxy = new TextProxy( node, parent.parent, parent, position.offset );
- this.position = position;
- return formatReturnValue( 'TEXT', textProxy, previousPosition, position, 1 );
- } else {
- // `node` is not set, we reached the end of current `parent`.
- position = Position.createAfter( parent );
- this.position = position;
- // We don't return `ELEMENT_END` for {@link engine.view.Text} element.
- if ( this.ignoreElementEnd || parent instanceof Text ) {
- return this._next();
- } else {
- return formatReturnValue( 'ELEMENT_END', parent, previousPosition, position );
- }
- }
- }
- /**
- * Makes a step backward in view. Moves the {@link #position} to the previous position and returns the encountered value.
- *
- * @private
- * @returns {Object}
- * @returns {Boolean} return.done True if iterator is done.
- * @returns {engine.view.TreeWalkerValue} return.value Information about taken step.
- */
- _previous() {
- let position = Position.createFromPosition( this.position );
- const previousPosition = this.position;
- const parent = position.parent;
- // We are at the beginning of the root.
- if ( parent.parent === null && position.offset === 0 ) {
- return { done: true };
- }
- // We reached the walker boundary.
- if ( parent == this._boundaryStartParent && position.offset == this.boundaries.start.offset ) {
- return { done: true };
- }
- // Get node just before current position.
- let node;
- // Text {@link engine.view.Text} element is a specific parent because contains string instead of child nodes.
- if ( parent instanceof Text ) {
- node = parent._data[ position.offset - 1 ];
- } else {
- node = parent.getChild( position.offset - 1 );
- }
- if ( node instanceof Element ) {
- if ( !this.shallow ) {
- position = new Position( node, node.getChildCount() );
- this.position = position;
- if ( this.ignoreElementEnd ) {
- return this._previous();
- } else {
- return formatReturnValue( 'ELEMENT_END', node, previousPosition, position );
- }
- } else {
- position.offset--;
- this.position = position;
- return formatReturnValue( 'ELEMENT_START', node, previousPosition, position, 1 );
- }
- } else if ( node instanceof Text ) {
- if ( this.singleCharacters ) {
- position = new Position( node, node._data.length );
- this.position = position;
- return this._previous();
- } else {
- let charactersCount = node._data.length;
- let item = node;
- // If text stick out of walker range, we need to cut it.
- if ( node == this._boundaryStartParent ) {
- const offset = this.boundaries.start.offset;
- const textFragment = node._data.substring( offset, charactersCount );
- charactersCount = textFragment.length;
- item = new TextProxy( textFragment, node.parent, node, offset );
- position = Position.createBefore( item );
- } else {
- // If not just move backward.
- position.offset--;
- }
- this.position = position;
- return formatReturnValue( 'TEXT', item, previousPosition, position, charactersCount );
- }
- } else if ( typeof node == 'string' ) {
- position.offset--;
- const textProxy = new TextProxy( node, parent.parent, parent, position.offset );
- this.position = position;
- return formatReturnValue( 'TEXT', textProxy, previousPosition, position, 1 );
- } else {
- // `node` is not set, we reached the beginning of current `parent`.
- position = Position.createBefore( parent );
- this.position = position;
- // We don't return `ELEMENT_START` for {@link engine.view.Text} element.
- if ( parent instanceof Text ) {
- return this._previous();
- }
- return formatReturnValue( 'ELEMENT_START', parent, previousPosition, position, 1 );
- }
- }
- }
- function formatReturnValue( type, item, previousPosition, nextPosition, length ) {
- return {
- done: false,
- value: {
- type: type,
- item: item,
- previousPosition: previousPosition,
- nextPosition: nextPosition,
- length: length
- }
- };
- }
- /**
- * Type of the step made by {@link engine.view.TreeWalker}.
- * Possible values: `'ELEMENT_START'` if walker is at the beginning of a node, `'ELEMENT_END'` if walker is at the end
- * of node, or `'TEXT'` if walker traversed over single and multiple characters.
- *
- * @typedef {String} engine.view.TreeWalkerValueType
- */
- /**
- * Object returned by {@link engine.view.TreeWalker} when traversing tree view.
- *
- * @typedef {Object} engine.view.TreeWalkerValue
- * @property {engine.view.TreeWalkerValueType} type
- * @property {engine.view.Item} item Item between old and new positions of {@link engine.view.TreeWalker}.
- * @property {engine.view.Position} previousPosition Previous position of the iterator.
- * * Forward iteration: For `'ELEMENT_END'` it is the last position inside the element. For all other types it is the
- * position before the item. Note that it is more efficient to use this position then calculate the position before
- * the node using {@link engine.view.Position.createBefore}.
- * * Backward iteration: For `'ELEMENT_START'` it is the first position inside the element. For all other types it is
- * the position after item.
- * @property {engine.view.Position} nextPosition Next position of the iterator.
- * * Forward iteration: For `'ELEMENT_START'` it is the first position inside the element. For all other types it is
- * the position after the item.
- * * Backward iteration: For `'ELEMENT_END'` it is last position inside element. For all other types it is the position
- * before the item.
- * @property {Number} [length] Length of the item. For `'ELEMENT_START'` it is 1. For `'TEXT'` it is
- * the length of the text. For `'ELEMENT_END'` it is undefined.
- */
- /**
- * Tree walking directions.
- *
- * @typedef {'FORWARD'|'BACKWARD'} engine.view.TreeWalkerDirection
- */
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