/** * @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/position */ import TreeWalker from './treewalker'; import compareArrays from '@ckeditor/ckeditor5-utils/src/comparearrays'; import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror'; // To check if component is loaded more than once. import '@ckeditor/ckeditor5-utils/src/version'; /** * Represents a position in the model tree. * * A position is represented by its {@link module:engine/model/position~Position#root} and * a {@link module:engine/model/position~Position#path} in that root. * * You can create position instances via its constructor or the `createPosition*()` factory methods of * {@link module:engine/model/model~Model} and {@link module:engine/model/writer~Writer}. * * **Note:** Position is based on offsets, not indexes. This means that a position between two text nodes * `foo` and `bar` has offset `3`, not `1`. See {@link module:engine/model/position~Position#path} for more information. * * Since a position in the model is represented by a {@link module:engine/model/position~Position#root position root} and * {@link module:engine/model/position~Position#path position path} it is possible to create positions placed in non-existing places. * This requirement is important for operational transformation algorithms. * * Also, {@link module:engine/model/operation/operation~Operation operations} * kept in the {@link module:engine/model/document~Document#history document history} * are storing positions (and ranges) which were correct when those operations were applied, but may not be correct * after the document has changed. * * When changes are applied to the model, it may also happen that {@link module:engine/model/position~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 module:engine/model/position~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. */ export default class Position { /** * Creates a position. * * @param {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} root Root of the position. * @param {Array.} path Position path. See {@link module:engine/model/position~Position#path}. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone'] Position stickiness. * See {@link module:engine/model/position~PositionStickiness}. */ constructor( root, path, stickiness = 'toNone' ) { if ( !root.is( 'element' ) && !root.is( 'documentFragment' ) ) { /** * Position root is invalid. * * Positions can only be anchored in elements or document fragments. * * @error model-position-root-invalid */ throw new CKEditorError( 'model-position-root-invalid', root ); } if ( !( path instanceof Array ) || path.length === 0 ) { /** * Position path must be an array with at least one item. * * @error model-position-path-incorrect-format * @param path */ throw new CKEditorError( 'model-position-path-incorrect-format', root, { path } ); } // Normalize the root and path when element (not root) is passed. if ( root.is( 'rootElement' ) ) { path = path.slice(); } else { path = [ ...root.getPath(), ...path ]; root = root.root; } /** * Root of the position path. * * @readonly * @member {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} * module:engine/model/position~Position#root */ this.root = root; /** * Position of the node in the tree. **Path contains offsets, not indexes.** * * Position can be placed before, after or in a {@link module:engine/model/node~Node node} if that node has * {@link module:engine/model/node~Node#offsetSize} greater than `1`. Items in position path are * {@link module:engine/model/node~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 module:engine/model/text~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 ] * * @readonly * @member {Array.} module:engine/model/position~Position#path */ this.path = path; /** * Position stickiness. See {@link module:engine/model/position~PositionStickiness}. * * @member {module:engine/model/position~PositionStickiness} module:engine/model/position~Position#stickiness */ this.stickiness = stickiness; } /** * Offset at which this position is located in its {@link module:engine/model/position~Position#parent parent}. It is equal * to the last item in position {@link module:engine/model/position~Position#path path}. * * @type {Number} */ get offset() { return this.path[ this.path.length - 1 ]; } 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 module:engine/model/position~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 {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} */ get parent() { let parent = this.root; for ( let i = 0; i < this.path.length - 1; i++ ) { parent = parent.getChild( parent.offsetToIndex( this.path[ i ] ) ); if ( !parent ) { throw new CKEditorError( 'model-position-path-incorrect', this, { position: this } ); } } if ( parent.is( '$text' ) ) { /** * The position's path is incorrect. This means that a position does not point to * a correct place in the tree and hence, some of its methods and getters cannot work correctly. * * **Note**: Unlike DOM and view positions, in the model, the * {@link module:engine/model/position~Position#parent position's parent} is always an element or a document fragment. * The last offset in the {@link module:engine/model/position~Position#path position's path} is the point in this element where * this position points. * * Read more about model positions and offsets in * the {@glink framework/guides/architecture/editing-engine#indexes-and-offsets Editing engine architecture guide}. * * @error position-incorrect-path * @param {module:engine/model/position~Position} position The incorrect position. */ throw new CKEditorError( 'model-position-path-incorrect', this, { position: this } ); } return parent; } /** * Position {@link module:engine/model/position~Position#offset offset} converted to an index in position's parent node. It is * equal to the {@link module:engine/model/node~Node#index 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 module:engine/model/text~Text text node} instance in which this position is placed or `null` if this * position is not in a text node. * * @readonly * @type {module:engine/model/text~Text|null} */ get textNode() { return getTextNodeAtPosition( this, this.parent ); } /** * Node directly after this position or `null` if this position is in text node. * * @readonly * @type {module:engine/model/node~Node|null} */ get nodeAfter() { // Cache the parent and reuse for performance reasons. See #6579 and #6582. const parent = this.parent; return getNodeAfterPosition( this, parent, getTextNodeAtPosition( this, parent ) ); } /** * Node directly before this position or `null` if this position is in text node. * * @readonly * @type {module:engine/model/node~Node|null} */ get nodeBefore() { // Cache the parent and reuse for performance reasons. See #6579 and #6582. const parent = this.parent; return getNodeBeforePosition( this, parent, getTextNodeAtPosition( this, parent ) ); } /** * Is `true` if position is at the beginning of its {@link module:engine/model/position~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 module:engine/model/position~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. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/position~Position} otherPosition Position to compare with. * @returns {module:engine/model/position~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: return this.path[ result ] < otherPosition.path[ result ] ? 'before' : 'after'; } } /** * Gets the farthest position which matches the callback using * {@link module:engine/model/treewalker~TreeWalker TreeWalker}. * * For example: * * getLastMatchingPosition( value => value.type == 'text' ); * // []foo -> foo[] * * getLastMatchingPosition( value => value.type == 'text', { direction: 'backward' } ); * // foo[] -> []foo * * getLastMatchingPosition( value => false ); * // Do not move the position. * * @param {Function} skip Callback function. Gets {@link module:engine/model/treewalker~TreeWalkerValue} and should * return `true` if the value should be skipped or `false` if not. * @param {Object} options Object with configuration options. See {@link module:engine/model/treewalker~TreeWalker}. * * @returns {module:engine/model/position~Position} The position after the last item which matches the `skip` callback test. */ getLastMatchingPosition( skip, options = {} ) { options.startPosition = this; const treeWalker = new TreeWalker( options ); treeWalker.skip( skip ); return treeWalker.position; } /** * Returns a path to this position's parent. Parent path is equal to position {@link module:engine/model/position~Position#path path} * but without the last item. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @returns {Array.} Path to the parent. */ getParentPath() { return this.path.slice( 0, -1 ); } /** * Returns ancestors array of this position, that is this position's parent and its ancestors. * * @returns {Array.} Array with ancestors. */ getAncestors() { const parent = this.parent; if ( parent.is( 'documentFragment' ) ) { return [ parent ]; } else { return parent.getAncestors( { includeSelf: true } ); } } /** * Returns the parent element of the given name. Returns null if the position is not inside the desired parent. * * @param {String} parentName The name of the parent element to find. * @returns {module:engine/model/element~Element|null} */ findAncestor( parentName ) { const parent = this.parent; if ( parent.is( 'element' ) ) { return parent.findAncestor( parentName, { includeSelf: true } ); } return null; } /** * Returns the slice of two position {@link #path paths} which is identical. The {@link #root roots} * of these two paths must be identical. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/position~Position} position The second position. * @returns {Array.} The common path. */ getCommonPath( position ) { if ( this.root != position.root ) { return []; } // We find on which tree-level start and end have the lowest common ancestor const cmp = compareArrays( this.path, position.path ); // If comparison returned string it means that arrays are same. const diffAt = ( typeof cmp == 'string' ) ? Math.min( this.path.length, position.path.length ) : cmp; return this.path.slice( 0, diffAt ); } /** * Returns an {@link module:engine/model/element~Element} or {@link module:engine/model/documentfragment~DocumentFragment} * which is a common ancestor of both positions. The {@link #root roots} of these two positions must be identical. * * @param {module:engine/model/position~Position} position The second position. * @returns {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment|null} */ getCommonAncestor( position ) { const ancestorsA = this.getAncestors(); const ancestorsB = position.getAncestors(); let i = 0; while ( ancestorsA[ i ] == ancestorsB[ i ] && ancestorsA[ i ] ) { i++; } return i === 0 ? null : ancestorsA[ i - 1 ]; } /** * Returns a new instance of `Position`, that has same {@link #parent parent} but it's offset * is shifted by `shift` value (can be a negative value). * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {Number} shift Offset shift. Can be a negative value. * @returns {module:engine/model/position~Position} Shifted position. */ getShiftedBy( shift ) { const shifted = this.clone(); const offset = shifted.offset + shift; shifted.offset = offset < 0 ? 0 : offset; return shifted; } /** * Checks whether this position is after given position. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @see module:engine/model/position~Position#isBefore * @param {module:engine/model/position~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. * } * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/position~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. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/position~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 {module:engine/model/position~Position} otherPosition Position to compare with. * @returns {Boolean} True if positions touch. */ isTouching( otherPosition ) { let left = null; let right = null; const compare = this.compareWith( otherPosition ); switch ( compare ) { case 'same': return true; case 'before': left = Position._createAt( this ); right = Position._createAt( otherPosition ); break; case 'after': left = Position._createAt( otherPosition ); right = Position._createAt( 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 ); } } } /** * Checks whether this object is of the given. * * position.is( 'position' ); // -> true * position.is( 'model:position' ); // -> true * * position.is( 'view:position' ); // -> false * position.is( 'documentSelection' ); // -> false * * {@link module:engine/model/node~Node#is Check the entire list of model objects} which implement the `is()` method. * * @param {String} type * @returns {Boolean} */ is( type ) { return type === 'position' || type === 'model:position'; } /** * Checks if two positions are in the same parent. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/position~Position} position Position to compare with. * @returns {Boolean} `true` if positions have the same parent, `false` otherwise. */ hasSameParentAs( position ) { if ( this.root !== position.root ) { return false; } const thisParentPath = this.getParentPath(); const posParentPath = position.getParentPath(); return compareArrays( thisParentPath, posParentPath ) == 'same'; } /** * Returns a copy of this position that is transformed by given `operation`. * * The new position's parameters are updated accordingly to the effect of the `operation`. * * For example, if `n` nodes are inserted before the position, the returned position {@link ~Position#offset} will be * increased by `n`. If the position was in a merged element, it will be accordingly moved to the new element, etc. * * This method is safe to use it on non-existing positions (for example during operational transformation). * * @param {module:engine/model/operation/operation~Operation} operation Operation to transform by. * @returns {module:engine/model/position~Position} Transformed position. */ getTransformedByOperation( operation ) { let result; switch ( operation.type ) { case 'insert': result = this._getTransformedByInsertOperation( operation ); break; case 'move': case 'remove': case 'reinsert': result = this._getTransformedByMoveOperation( operation ); break; case 'split': result = this._getTransformedBySplitOperation( operation ); break; case 'merge': result = this._getTransformedByMergeOperation( operation ); break; default: result = Position._createAt( this ); break; } return result; } /** * Returns a copy of this position transformed by an insert operation. * * @protected * @param {module:engine/model/operation/insertoperation~InsertOperation} operation * @returns {module:engine/model/position~Position} */ _getTransformedByInsertOperation( operation ) { return this._getTransformedByInsertion( operation.position, operation.howMany ); } /** * Returns a copy of this position transformed by a move operation. * * @protected * @param {module:engine/model/operation/moveoperation~MoveOperation} operation * @returns {module:engine/model/position~Position} */ _getTransformedByMoveOperation( operation ) { return this._getTransformedByMove( operation.sourcePosition, operation.targetPosition, operation.howMany ); } /** * Returns a copy of this position transformed by a split operation. * * @protected * @param {module:engine/model/operation/splitoperation~SplitOperation} operation * @returns {module:engine/model/position~Position} */ _getTransformedBySplitOperation( operation ) { const movedRange = operation.movedRange; const isContained = movedRange.containsPosition( this ) || ( movedRange.start.isEqual( this ) && this.stickiness == 'toNext' ); if ( isContained ) { return this._getCombined( operation.splitPosition, operation.moveTargetPosition ); } else { if ( operation.graveyardPosition ) { return this._getTransformedByMove( operation.graveyardPosition, operation.insertionPosition, 1 ); } else { return this._getTransformedByInsertion( operation.insertionPosition, 1 ); } } } /** * Returns a copy of this position transformed by merge operation. * * @protected * @param {module:engine/model/operation/mergeoperation~MergeOperation} operation * @returns {module:engine/model/position~Position} */ _getTransformedByMergeOperation( operation ) { const movedRange = operation.movedRange; const isContained = movedRange.containsPosition( this ) || movedRange.start.isEqual( this ); let pos; if ( isContained ) { pos = this._getCombined( operation.sourcePosition, operation.targetPosition ); if ( operation.sourcePosition.isBefore( operation.targetPosition ) ) { // Above happens during OT when the merged element is moved before the merged-to element. pos = pos._getTransformedByDeletion( operation.deletionPosition, 1 ); } } else if ( this.isEqual( operation.deletionPosition ) ) { pos = Position._createAt( operation.deletionPosition ); } else { pos = this._getTransformedByMove( operation.deletionPosition, operation.graveyardPosition, 1 ); } return pos; } /** * 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 {module:engine/model/position~Position} deletePosition Position before the first removed node. * @param {Number} howMany How many nodes are removed. * @returns {module:engine/model/position~Position|null} Transformed position or `null`. */ _getTransformedByDeletion( deletePosition, howMany ) { const transformed = Position._createAt( 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 {module:engine/model/position~Position} insertPosition Position where nodes are inserted. * @param {Number} howMany How many nodes are inserted. * @returns {module:engine/model/position~Position} Transformed position. */ _getTransformedByInsertion( insertPosition, howMany ) { const transformed = Position._createAt( 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 && this.stickiness != 'toPrevious' ) ) { // 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 {module:engine/model/position~Position} sourcePosition Position before the first element to move. * @param {module:engine/model/position~Position} targetPosition Position where moved elements will be inserted. * @param {Number} howMany How many consecutive nodes to move, starting from `sourcePosition`. * @returns {module:engine/model/position~Position} Transformed position. */ _getTransformedByMove( sourcePosition, targetPosition, howMany ) { // Update target position, as it could be affected by nodes removal. targetPosition = targetPosition._getTransformedByDeletion( sourcePosition, howMany ); if ( sourcePosition.isEqual( targetPosition ) ) { // If `targetPosition` is equal to `sourcePosition` this isn't really any move. Just return position as it is. return Position._createAt( this ); } // Moving a range removes nodes from their original position. We acknowledge this by proper transformation. const transformed = this._getTransformedByDeletion( sourcePosition, howMany ); const isMoved = transformed === null || ( sourcePosition.isEqual( this ) && this.stickiness == 'toNext' ) || ( sourcePosition.getShiftedBy( howMany ).isEqual( this ) && this.stickiness == 'toPrevious' ); if ( isMoved ) { // 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. return 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. return transformed._getTransformedByInsertion( targetPosition, howMany ); } } /** * 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 = model.createPositionFromPath( root, [ 2, 3, 1 ] ); * let source = model.createPositionFromPath( root, [ 2, 2 ] ); * let target = model.createPositionFromPath( 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 {module:engine/model/position~Position} source Beginning of the moved range. * @param {module:engine/model/position~Position} target Position where the range is moved. * @returns {module:engine/model/position~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. const combined = Position._createAt( target ); combined.stickiness = this.stickiness; // 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, ...this.path.slice( i + 1 ) ]; return combined; } /** * @inheritDoc */ toJSON() { return { root: this.root.toJSON(), path: Array.from( this.path ), stickiness: this.stickiness }; } /** * Returns a new position that is equal to current position. * * @returns {module:engine/model/position~Position} */ clone() { return new this.constructor( this.root, this.path, this.stickiness ); } /** * Creates position at the given location. The location can be specified as: * * * a {@link module:engine/model/position~Position position}, * * parent element and offset (offset defaults to `0`), * * parent element and `'end'` (sets position at the end of that element), * * {@link module:engine/model/item~Item model item} and `'before'` or `'after'` (sets position before or after given model item). * * This method is a shortcut to other factory methods such as: * * * {@link module:engine/model/position~Position._createBefore}, * * {@link module:engine/model/position~Position._createAfter}. * * @param {module:engine/model/item~Item|module:engine/model/position~Position} itemOrPosition * @param {Number|'end'|'before'|'after'} [offset] Offset or one of the flags. Used only when the * first parameter is a {@link module:engine/model/item~Item model item}. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone'] Position stickiness. Used only when the * first parameter is a {@link module:engine/model/item~Item model item}. * @protected */ static _createAt( itemOrPosition, offset, stickiness = 'toNone' ) { if ( itemOrPosition instanceof Position ) { return new Position( itemOrPosition.root, itemOrPosition.path, itemOrPosition.stickiness ); } else { const node = itemOrPosition; if ( offset == 'end' ) { offset = node.maxOffset; } else if ( offset == 'before' ) { return this._createBefore( node, stickiness ); } else if ( offset == 'after' ) { return this._createAfter( node, stickiness ); } else if ( offset !== 0 && !offset ) { /** * {@link module:engine/model/model~Model#createPositionAt `Model#createPositionAt()`} * requires the offset to be specified when the first parameter is a model item. * * @error model-createPositionAt-offset-required */ throw new CKEditorError( 'model-createpositionat-offset-required', [ this, itemOrPosition ] ); } if ( !node.is( 'element' ) && !node.is( 'documentFragment' ) ) { /** * Position parent have to be a model element or model document fragment. * * @error model-position-parent-incorrect */ throw new CKEditorError( 'model-position-parent-incorrect', [ this, itemOrPosition ] ); } const path = node.getPath(); path.push( offset ); return new this( node.root, path, stickiness ); } } /** * Creates a new position, after given {@link module:engine/model/item~Item model item}. * * @param {module:engine/model/item~Item} item Item after which the position should be placed. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone'] Position stickiness. * @returns {module:engine/model/position~Position} * @protected */ static _createAfter( item, stickiness ) { if ( !item.parent ) { /** * You can not make a position after a root element. * * @error model-position-after-root * @param {module:engine/model/item~Item} root */ throw new CKEditorError( 'model-position-after-root', [ this, item ], { root: item } ); } return this._createAt( item.parent, item.endOffset, stickiness ); } /** * Creates a new position, before the given {@link module:engine/model/item~Item model item}. * * @param {module:engine/model/item~Item} item Item before which the position should be placed. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone'] Position stickiness. * @returns {module:engine/model/position~Position} * @protected */ static _createBefore( item, stickiness ) { if ( !item.parent ) { /** * You can not make a position before a root element. * * @error model-position-before-root * @param {module:engine/model/item~Item} root */ throw new CKEditorError( 'model-position-before-root', item, { root: item } ); } return this._createAt( item.parent, item.startOffset, stickiness ); } /** * Creates a `Position` instance from given plain object (i.e. parsed JSON string). * * @param {Object} json Plain object to be converted to `Position`. * @param {module:engine/model/document~Document} doc Document object that will be position owner. * @returns {module:engine/model/position~Position} `Position` instance created using given plain object. */ static fromJSON( json, doc ) { if ( json.root === '$graveyard' ) { const pos = new Position( doc.graveyard, json.path ); pos.stickiness = json.stickiness; return pos; } if ( !doc.getRoot( json.root ) ) { /** * Cannot create position for document. Root with specified name does not exist. * * @error model-position-fromjson-no-root * @param {String} rootName */ throw new CKEditorError( 'model-position-fromjson-no-root', doc, { rootName: json.root } ); } return new Position( doc.getRoot( json.root ), json.path, json.stickiness ); } // @if CK_DEBUG_ENGINE // toString() { // @if CK_DEBUG_ENGINE // return `${ this.root } [ ${ this.path.join( ', ' ) } ]`; // @if CK_DEBUG_ENGINE // } // @if CK_DEBUG_ENGINE // log() { // @if CK_DEBUG_ENGINE // console.log( 'ModelPosition: ' + this ); // @if CK_DEBUG_ENGINE // } } /** * 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} module:engine/model/position~PositionRelation */ /** * Represents how position is "sticking" with neighbour nodes. Used to define how position should be transformed (moved) * in edge cases. Possible values: `'toNone'`, `'toNext'`, `'toPrevious'`. * * Examples: * * Insert. Position is at | and nodes are inserted at the same position, marked as ^: * * - sticks to none:

f^|oo

->

fbar|oo

* - sticks to next node:

f^|oo

->

fbar|oo

* - sticks to previous node:

f|^oo

->

f|baroo

* * * Move. Position is at | and range [oo] is moved to position ^: * * - sticks to none:

f|[oo]

b^ar

->

f|

booar

* - sticks to none:

f[oo]|

b^ar

->

f|

booar

* * - sticks to next node:

f|[oo]

b^ar

->

f

b|ooar

* - sticks to next node:

f[oo]|

b^ar

->

f|

booar

* * - sticks to previous node:

f|[oo]

b^ar

->

f|

booar

* - sticks to previous node:

f[oo]|

b^ar

->

f

boo|ar

* * @typedef {String} module:engine/model/position~PositionStickiness */ /** * Returns a text node at the given position. * * This is a helper function optimized to reuse the position parent instance for performance reasons. * * Normally, you should use {@link module:engine/model/position~Position#textNode `Position#textNode`}. * If you start hitting performance issues with {@link module:engine/model/position~Position#parent `Position#parent`} * check if your algorithm does not access it multiple times (which can happen directly or indirectly via other position properties). * * See https://github.com/ckeditor/ckeditor5/issues/6579. * * See also: * * * {@link module:engine/model/position~getNodeAfterPosition} * * {@link module:engine/model/position~getNodeBeforePosition} * * @param {module:engine/model/position~Position} position * @param {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} positionParent The parent of the * given position. * @returns {module:engine/model/text~Text|null} */ export function getTextNodeAtPosition( position, positionParent ) { const node = positionParent.getChild( positionParent.offsetToIndex( position.offset ) ); if ( node && node.is( '$text' ) && node.startOffset < position.offset ) { return node; } return null; } /** * Returns the node after the given position. * * This is a helper function optimized to reuse the position parent instance and the calculation of the text node at the * specific position for performance reasons. * * Normally, you should use {@link module:engine/model/position~Position#nodeAfter `Position#nodeAfter`}. * If you start hitting performance issues with {@link module:engine/model/position~Position#parent `Position#parent`} and/or * {@link module:engine/model/position~Position#textNode `Position#textNode`} * check if your algorithm does not access those properties multiple times * (which can happen directly or indirectly via other position properties). * * See https://github.com/ckeditor/ckeditor5/issues/6579 and https://github.com/ckeditor/ckeditor5/issues/6582. * * See also: * * * {@link module:engine/model/position~getTextNodeAtPosition} * * {@link module:engine/model/position~getNodeBeforePosition} * * @param {module:engine/model/position~Position} position * @param {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} positionParent The parent of the * given position. * @param {module:engine/model/text~Text|null} textNode Text node at the given position. * @returns {module:engine/model/node~Node|null} */ export function getNodeAfterPosition( position, positionParent, textNode ) { if ( textNode !== null ) { return null; } return positionParent.getChild( positionParent.offsetToIndex( position.offset ) ); } /** * Returns the node before the given position. * * Refer to {@link module:engine/model/position~getNodeBeforePosition} for documentation on when to use this util method. * * See also: * * * {@link module:engine/model/position~getTextNodeAtPosition} * * {@link module:engine/model/position~getNodeAfterPosition} * * @param {module:engine/model/position~Position} position * @param {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment} positionParent The parent of the * given position. * @param {module:engine/model/text~Text|null} textNode Text node at the given position. * @returns {module:engine/model/node~Node|null} */ export function getNodeBeforePosition( position, positionParent, textNode ) { if ( textNode !== null ) { return null; } return positionParent.getChild( positionParent.offsetToIndex( position.offset ) - 1 ); }