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- /**
- * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md.
- */
- import DocumentFragment from './documentfragment.js';
- import Element from './element.js';
- import last from '../../utils/lib/lodash/last.js';
- import compareArrays from '../../utils/comparearrays';
- import CKEditorError from '../../utils/ckeditorerror.js';
- import Text from './text.js';
- /**
- * Represents a position in the model tree.
- *
- * **Note:** Position is based on offsets, not indexes. This means that position in element containing two text nodes
- * with data `foo` and `bar`, position between them has offset `3`, not `1`. See {@link engine.model.Position#path} for more.
- *
- * Since position in a model is represented by a {@link engine.model.Position#root position root} and
- * {@link engine.model.Position#path position path} it is possible to create positions placed in non-existing elements.
- * This requirement is important for {@link engine.model.operation.transfrom operational transformation}.
- *
- * Also, {@link engine.model.operation.Operation operations} kept in {@link engine.model.Document#history document history}
- * are storing positions (and ranges) which were correct when those operations were applied, but may not be correct
- * after document got changed.
- *
- * When changes are applied to model, it may also happen that {@link engine.model.Position#parent position parent} will change
- * even if position path has not changed. Keep in mind, that if a position leads to non-existing element,
- * {@link engine.model.Position#parent} and some other properties and methods will throw errors.
- *
- * In most cases, position with wrong path is caused by an error in code, but it is sometimes needed, as described above.
- *
- * @memberOf engine.model
- */
- export default class Position {
- /**
- * Creates a position.
- *
- * @param {engine.model.Element|engine.model.DocumentFragment} root Root of the position.
- * @param {Array.<Number>} path Position path. See {@link engine.model.Position#path}.
- */
- constructor( root, path ) {
- if ( !( root instanceof Element ) && !( root instanceof DocumentFragment ) ) {
- /**
- * Position root invalid.
- *
- * @error position-root-invalid.
- */
- throw new CKEditorError( 'position-root-invalid: Position root invalid.' );
- }
- if ( !( path instanceof Array ) || path.length === 0 ) {
- /**
- * Position path must be an Array with at least one item.
- *
- * @error position-path-incorrect
- * @param path
- */
- throw new CKEditorError( 'position-path-incorrect: Position path must be an Array with at least one item.', { path: path } );
- }
- // Normalize the root and path (if element was passed).
- path = root.getPath().concat( path );
- root = root.root;
- /**
- * Root of the position path.
- *
- * @readonly
- * @member {engine.model.Element|engine.model.DocumentFragment} engine.model.Position#root
- */
- this.root = root;
- /**
- * Position of the node it the tree. Path is described through offsets, not indexes.
- *
- * Position can be placed before, after or in a {@link engine.model.Node node} if that node has
- * {@link engine.model.Node#offsetSize} greater than `1`. Items in position path are
- * {@link engine.model.Node#startOffset starting offsets} of position ancestors, starting from direct root children,
- * down to the position offset in it's parent.
- *
- * ROOT
- * |- P before: [ 0 ] after: [ 1 ]
- * |- UL before: [ 1 ] after: [ 2 ]
- * |- LI before: [ 1, 0 ] after: [ 1, 1 ]
- * | |- foo before: [ 1, 0, 0 ] after: [ 1, 0, 3 ]
- * |- LI before: [ 1, 1 ] after: [ 1, 2 ]
- * |- bar before: [ 1, 1, 0 ] after: [ 1, 1, 3 ]
- *
- * `foo` and `bar` are representing {@link engine.model.Text text nodes}. Since text nodes has offset size
- * greater than `1` you can place position offset between their start and end:
- *
- * ROOT
- * |- P
- * |- UL
- * |- LI
- * | |- f^o|o ^ has path: [ 1, 0, 1 ] | has path: [ 1, 0, 2 ]
- * |- LI
- * |- b^a|r ^ has path: [ 1, 1, 1 ] | has path: [ 1, 1, 2 ]
- *
- * @member {Array.<Number>} engine.model.Position#path
- */
- this.path = path;
- }
- /**
- * Offset at which this position is located in it's {@link engine.model.Position#parent parent}. It is equal
- * to the last item in position {@link engine.model.Position#path path}.
- *
- * @type {Number}
- */
- get offset() {
- return last( this.path );
- }
- /**
- * @param {Number} newOffset
- */
- set offset( newOffset ) {
- this.path[ this.path.length - 1 ] = newOffset;
- }
- /**
- * Parent element of this position.
- *
- * Keep in mind that `parent` value is calculated when the property is accessed. If {@link engine.model.Position#path position path}
- * leads to a non-existing element, `parent` property will throw error.
- *
- * Also it is a good idea to cache `parent` property if it is used frequently in an algorithm (i.e. in a long loop).
- *
- * @readonly
- * @type {engine.model.Element}
- */
- get parent() {
- let parent = this.root;
- for ( let i = 0; i < this.path.length - 1; i++ ) {
- parent = parent.getChild( parent.offsetToIndex( this.path[ i ] ) );
- }
- return parent;
- }
- /**
- * Position {@link engine.model.Position#offset offset} converted to an index in position's parent node. It is
- * equal to the {@link engine.model.Node#getIndex index} of a node after this position. If position is placed
- * in text node, position index is equal to the index of that text node.
- *
- * @readonly
- * @type {Number}
- */
- get index() {
- return this.parent.offsetToIndex( this.offset );
- }
- /**
- * Returns {@link engine.model.Text text node} instance in which this position is placed or `null` if this
- * position is not in a text node.
- *
- * @readonly
- * @type {engine.model.Text|null}
- */
- get textNode() {
- let node = this.parent.getChild( this.index );
- return ( node instanceof Text && node.startOffset < this.offset ) ? node : null;
- }
- /**
- * Node directly after this position or `null` if this position is in text node.
- *
- * @readonly
- * @type {engine.model.Node|null}
- */
- get nodeAfter() {
- return this.textNode === null ? this.parent.getChild( this.index ) : null;
- }
- /**
- * Node directly before this position or `null` if this position is in text node.
- *
- * @readonly
- * @type {Node}
- */
- get nodeBefore() {
- return this.textNode === null ? this.parent.getChild( this.index - 1 ) : null;
- }
- /**
- * Is `true` if position is at the beginning of its {@link engine.model.Position#parent parent}, `false` otherwise.
- *
- * @readonly
- * @type {Boolean}
- */
- get isAtStart() {
- return this.offset === 0;
- }
- /**
- * Is `true` if position is at the end of its {@link engine.model.Position#parent parent}, `false` otherwise.
- *
- * @readonly
- * @type {Boolean}
- */
- get isAtEnd() {
- return this.offset == this.parent.maxOffset;
- }
- /**
- * Checks whether this position is before or after given position.
- *
- * @param {engine.model.Position} otherPosition Position to compare with.
- * @returns {engine.model.PositionRelation}
- */
- compareWith( otherPosition ) {
- if ( this.root != otherPosition.root ) {
- return 'different';
- }
- const result = compareArrays( this.path, otherPosition.path );
- switch ( result ) {
- case 'same':
- return 'same';
- case 'prefix':
- return 'before';
- case 'extension':
- return 'after';
- default:
- if ( this.path[ result ] < otherPosition.path[ result ] ) {
- return 'before';
- } else {
- return 'after';
- }
- }
- }
- /**
- * Returns a path to this position's parent. Parent path is equal to position {@link engine.model.Position#path path}
- * but without the last item.
- *
- * This method returns the parent path even if the parent does not exists.
- *
- * @returns {Array.<Number>} Path to the parent.
- */
- getParentPath() {
- return this.path.slice( 0, -1 );
- }
- /**
- * Returns a new instance of `Position`, that has same {@link engine.model.Position#parent parent} but it's offset
- * is shifted by `shift` value (can be a negative value).
- *
- * @param {Number} shift Offset shift. Can be a negative value.
- * @returns {engine.model.Position} Shifted position.
- */
- getShiftedBy( shift ) {
- let shifted = Position.createFromPosition( this );
- let offset = shifted.offset + shift;
- shifted.offset = offset < 0 ? 0 : offset;
- return shifted;
- }
- /**
- * Checks whether this position is after given position.
- *
- * @see engine.model.Position#isBefore
- *
- * @param {engine.model.Position} otherPosition Position to compare with.
- * @returns {Boolean} True if this position is after given position.
- */
- isAfter( otherPosition ) {
- return this.compareWith( otherPosition ) == 'after';
- }
- /**
- * Checks whether this position is before given position.
- *
- * **Note:** watch out when using negation of the value returned by this method, because the negation will also
- * be `true` if positions are in different roots and you might not expect this. You should probably use
- * `a.isAfter( b ) || a.isEqual( b )` or `!a.isBefore( p ) && a.root == b.root` in most scenarios. If your
- * condition uses multiple `isAfter` and `isBefore` checks, build them so they do not use negated values, i.e.:
- *
- * if ( a.isBefore( b ) && c.isAfter( d ) ) {
- * // do A.
- * } else {
- * // do B.
- * }
- *
- * or, if you have only one if-branch:
- *
- * if ( !( a.isBefore( b ) && c.isAfter( d ) ) {
- * // do B.
- * }
- *
- * rather than:
- *
- * if ( !a.isBefore( b ) || && !c.isAfter( d ) ) {
- * // do B.
- * } else {
- * // do A.
- * }
- *
- * @param {engine.model.Position} otherPosition Position to compare with.
- * @returns {Boolean} True if this position is before given position.
- */
- isBefore( otherPosition ) {
- return this.compareWith( otherPosition ) == 'before';
- }
- /**
- * Checks whether this position is equal to given position.
- *
- * @param {engine.model.Position} otherPosition Position to compare with.
- * @returns {Boolean} True if positions are same.
- */
- isEqual( otherPosition ) {
- return this.compareWith( otherPosition ) == 'same';
- }
- /**
- * Checks whether this position is touching given position. Positions touch when there are no text nodes
- * or empty nodes in a range between them. Technically, those positions are not equal but in many cases
- * they are very similar or even indistinguishable.
- *
- * @param {engine.model.Position} otherPosition Position to compare with.
- * @returns {Boolean} True if positions touch.
- */
- isTouching( otherPosition ) {
- let left = null;
- let right = null;
- let compare = this.compareWith( otherPosition );
- switch ( compare ) {
- case 'same':
- return true;
- case 'before':
- left = Position.createFromPosition( this );
- right = Position.createFromPosition( otherPosition );
- break;
- case 'after':
- left = Position.createFromPosition( otherPosition );
- right = Position.createFromPosition( this );
- break;
- default:
- return false;
- }
- // Cached for optimization purposes.
- let leftParent = left.parent;
- while ( left.path.length + right.path.length ) {
- if ( left.isEqual( right ) ) {
- return true;
- }
- if ( left.path.length > right.path.length ) {
- if ( left.offset !== leftParent.maxOffset ) {
- return false;
- }
- left.path = left.path.slice( 0, -1 );
- leftParent = leftParent.parent;
- left.offset++;
- } else {
- if ( right.offset !== 0 ) {
- return false;
- }
- right.path = right.path.slice( 0, -1 );
- }
- }
- }
- /**
- * Returns a copy of this position that is updated by removing `howMany` nodes starting from `deletePosition`.
- * It may happen that this position is in a removed node. If that is the case, `null` is returned instead.
- *
- * @protected
- * @param {engine.model.Position} deletePosition Position before the first removed node.
- * @param {Number} howMany How many nodes are removed.
- * @returns {engine.model.Position|null} Transformed position or `null`.
- */
- _getTransformedByDeletion( deletePosition, howMany ) {
- let transformed = Position.createFromPosition( this );
- // This position can't be affected if deletion was in a different root.
- if ( this.root != deletePosition.root ) {
- return transformed;
- }
- if ( compareArrays( deletePosition.getParentPath(), this.getParentPath() ) == 'same' ) {
- // If nodes are removed from the node that is pointed by this position...
- if ( deletePosition.offset < this.offset ) {
- // And are removed from before an offset of that position...
- if ( deletePosition.offset + howMany > this.offset ) {
- // Position is in removed range, it's no longer in the tree.
- return null;
- } else {
- // Decrement the offset accordingly.
- transformed.offset -= howMany;
- }
- }
- } else if ( compareArrays( deletePosition.getParentPath(), this.getParentPath() ) == 'prefix' ) {
- // If nodes are removed from a node that is on a path to this position...
- const i = deletePosition.path.length - 1;
- if ( deletePosition.offset <= this.path[ i ] ) {
- // And are removed from before next node of that path...
- if ( deletePosition.offset + howMany > this.path[ i ] ) {
- // If the next node of that path is removed return null
- // because the node containing this position got removed.
- return null;
- } else {
- // Otherwise, decrement index on that path.
- transformed.path[ i ] -= howMany;
- }
- }
- }
- return transformed;
- }
- /**
- * Returns a copy of this position that is updated by inserting `howMany` nodes at `insertPosition`.
- *
- * @protected
- * @param {engine.model.Position} insertPosition Position where nodes are inserted.
- * @param {Number} howMany How many nodes are inserted.
- * @param {Boolean} insertBefore Flag indicating whether nodes are inserted before or after `insertPosition`.
- * This is important only when `insertPosition` and this position are same. If that is the case and the flag is
- * set to `true`, this position will get transformed. If the flag is set to `false`, it won't.
- * @returns {engine.model.Position} Transformed position.
- */
- _getTransformedByInsertion( insertPosition, howMany, insertBefore ) {
- let transformed = Position.createFromPosition( this );
- // This position can't be affected if insertion was in a different root.
- if ( this.root != insertPosition.root ) {
- return transformed;
- }
- if ( compareArrays( insertPosition.getParentPath(), this.getParentPath() ) == 'same' ) {
- // If nodes are inserted in the node that is pointed by this position...
- if ( insertPosition.offset < this.offset || ( insertPosition.offset == this.offset && insertBefore ) ) {
- // And are inserted before an offset of that position...
- // "Push" this positions offset.
- transformed.offset += howMany;
- }
- } else if ( compareArrays( insertPosition.getParentPath(), this.getParentPath() ) == 'prefix' ) {
- // If nodes are inserted in a node that is on a path to this position...
- const i = insertPosition.path.length - 1;
- if ( insertPosition.offset <= this.path[ i ] ) {
- // And are inserted before next node of that path...
- // "Push" the index on that path.
- transformed.path[ i ] += howMany;
- }
- }
- return transformed;
- }
- /**
- * Returns a copy of this position that is updated by moving `howMany` nodes from `sourcePosition` to `targetPosition`.
- *
- * @protected
- * @param {engine.model.Position} sourcePosition Position before the first element to move.
- * @param {engine.model.Position} targetPosition Position where moved elements will be inserted.
- * @param {Number} howMany How many consecutive nodes to move, starting from `sourcePosition`.
- * @param {Boolean} insertBefore Flag indicating whether moved nodes are pasted before or after `insertPosition`.
- * This is important only when `targetPosition` and this position are same. If that is the case and the flag is
- * set to `true`, this position will get transformed by range insertion. If the flag is set to `false`, it won't.
- * @param {Boolean} [sticky] Flag indicating whether this position "sticks" to range, that is if it should be moved
- * with the moved range if it is equal to one of range's boundaries.
- * @returns {engine.model.Position} Transformed position.
- */
- _getTransformedByMove( sourcePosition, targetPosition, howMany, insertBefore, sticky ) {
- // Moving a range removes nodes from their original position. We acknowledge this by proper transformation.
- let transformed = this._getTransformedByDeletion( sourcePosition, howMany );
- // Then we update target position, as it could be affected by nodes removal too.
- targetPosition = targetPosition._getTransformedByDeletion( sourcePosition, howMany );
- if ( transformed === null || ( sticky && transformed.isEqual( sourcePosition ) ) ) {
- // This position is inside moved range (or sticks to it).
- // In this case, we calculate a combination of this position, move source position and target position.
- transformed = this._getCombined( sourcePosition, targetPosition );
- } else {
- // This position is not inside a removed range.
- // In next step, we simply reflect inserting `howMany` nodes, which might further affect the position.
- transformed = transformed._getTransformedByInsertion( targetPosition, howMany, insertBefore );
- }
- return transformed;
- }
- /**
- * Returns a new position that is a combination of this position and given positions.
- *
- * The combined position is a copy of this position transformed by moving a range starting at `source` position
- * to the `target` position. It is expected that this position is inside the moved range.
- *
- * Example:
- *
- * let original = new Position( root, [ 2, 3, 1 ] );
- * let source = new Position( root, [ 2, 2 ] );
- * let target = new Position( otherRoot, [ 1, 1, 3 ] );
- * original._getCombined( source, target ); // path is [ 1, 1, 4, 1 ], root is `otherRoot`
- *
- * Explanation:
- *
- * We have a position `[ 2, 3, 1 ]` and move some nodes from `[ 2, 2 ]` to `[ 1, 1, 3 ]`. The original position
- * was inside moved nodes and now should point to the new place. The moved nodes will be after
- * positions `[ 1, 1, 3 ]`, `[ 1, 1, 4 ]`, `[ 1, 1, 5 ]`. Since our position was in the second moved node,
- * the transformed position will be in a sub-tree of a node at `[ 1, 1, 4 ]`. Looking at original path, we
- * took care of `[ 2, 3 ]` part of it. Now we have to add the rest of the original path to the transformed path.
- * Finally, the transformed position will point to `[ 1, 1, 4, 1 ]`.
- *
- * @protected
- * @param {engine.model.Position} source Beginning of the moved range.
- * @param {engine.model.Position} target Position where the range is moved.
- * @returns {engine.model.Position} Combined position.
- */
- _getCombined( source, target ) {
- const i = source.path.length - 1;
- // The first part of a path to combined position is a path to the place where nodes were moved.
- let combined = Position.createFromPosition( target );
- // Then we have to update the rest of the path.
- // Fix the offset because this position might be after `from` position and we have to reflect that.
- combined.offset = combined.offset + this.path[ i ] - source.offset;
- // Then, add the rest of the path.
- // If this position is at the same level as `from` position nothing will get added.
- combined.path = combined.path.concat( this.path.slice( i + 1 ) );
- return combined;
- }
- /**
- * Creates position at the given location. The location can be specified as:
- *
- * * a {@link engine.model.Position position},
- * * parent element and offset (offset defaults to `0`),
- * * parent element and `'end'` (sets position at the end of that element),
- * * {@link engine.model.Item model item} and `'before'` or `'after'` (sets position before or after given model item).
- *
- * This method is a shortcut to other constructors such as:
- *
- * * {@link engine.model.Position.createBefore},
- * * {@link engine.model.Position.createAfter},
- * * {@link engine.model.Position.createFromParentAndOffset},
- * * {@link engine.model.Position.createFromPosition}.
- *
- * @param {engine.model.Item|engine.model.Position} itemOrPosition
- * @param {Number|'end'|'before'|'after'} [offset=0] Offset or one of the flags. Used only when
- * first parameter is a {@link engine.model.Item model item}.
- */
- static createAt( itemOrPosition, offset ) {
- if ( itemOrPosition instanceof Position ) {
- return this.createFromPosition( itemOrPosition );
- } else {
- const node = itemOrPosition;
- if ( offset == 'end' ) {
- offset = node.maxOffset;
- } else if ( offset == 'before' ) {
- return this.createBefore( node );
- } else if ( offset == 'after' ) {
- return this.createAfter( node );
- } else if ( !offset ) {
- offset = 0;
- }
- return this.createFromParentAndOffset( node, offset );
- }
- }
- /**
- * Creates a new position, after given {@link engine.model.Item model item}.
- *
- * @param {engine.model.Item} item Item after which the position should be placed.
- * @returns {engine.model.Position}
- */
- static createAfter( item ) {
- if ( !item.parent ) {
- /**
- * You can not make position after root.
- *
- * @error position-after-root
- * @param {engine.model.Item} root
- */
- throw new CKEditorError( 'position-after-root: You can not make position after root.', { root: item } );
- }
- return this.createFromParentAndOffset( item.parent, item.endOffset );
- }
- /**
- * Creates a new position, before the given {@link engine.model.Item model item}.
- *
- * @param {engine.model.Item} item Item before which the position should be placed.
- * @returns {engine.model.Position}
- */
- static createBefore( item ) {
- if ( !item.parent ) {
- /**
- * You can not make position before root.
- *
- * @error position-before-root
- * @param {engine.model.Item} root
- */
- throw new CKEditorError( 'position-before-root: You can not make position before root.', { root: item } );
- }
- return this.createFromParentAndOffset( item.parent, item.startOffset );
- }
- /**
- * Creates a new position from the parent element and an offset in that element.
- *
- * @param {engine.model.Element|engine.model.DocumentFragment} parent Position's parent.
- * @param {Number} offset Position's offset.
- * @returns {engine.model.Position}
- */
- static createFromParentAndOffset( parent, offset ) {
- if ( !( parent instanceof Element || parent instanceof DocumentFragment ) ) {
- /**
- * Position parent have to be a model element or model document fragment.
- *
- * @error position-parent-incorrect
- */
- throw new CKEditorError( 'position-parent-incorrect: Position parent have to be a element or document fragment.' );
- }
- const path = parent.getPath();
- path.push( offset );
- return new this( parent.root, path );
- }
- /**
- * Creates a new position, which is equal to passed position.
- *
- * @param {engine.model.Position} position Position to be cloned.
- * @returns {engine.model.Position}
- */
- static createFromPosition( position ) {
- return new this( position.root, position.path.slice() );
- }
- /**
- * Creates a `Position` instance from given plain object (i.e. parsed JSON string).
- *
- * @param {Object} json Plain object to be converted to `Position`.
- * @returns {engine.model.Position} `Position` instance created using given plain object.
- */
- static fromJSON( json, doc ) {
- if ( json.root === '$graveyard' ) {
- return new Position( doc.graveyard, json.path );
- }
- if ( !doc.hasRoot( json.root ) ) {
- /**
- * Cannot create position for document. Root with specified name does not exist.
- *
- * @error position-fromjson-no-root
- * @param {String} rootName
- */
- throw new CKEditorError(
- 'position-fromjson-no-root: Cannot create position for document. Root with specified name does not exist.',
- { rootName: json.root }
- );
- }
- return new Position( doc.getRoot( json.root ), json.path );
- }
- }
- /**
- * A flag indicating whether this position is `'before'` or `'after'` or `'same'` as given position.
- * If positions are in different roots `'different'` flag is returned.
- *
- * @typedef {String} engine.model.PositionRelation
- */
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