@ckeditor/ckeditor5-engine
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The editing engine of CKEditor 5 – the best browser-based rich text editor.
399 lines (398 loc) • 18.3 kB
JavaScript
/**
* @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/**
* @module engine/model/document
*/
import { Differ } from './differ.js';
import { ModelDocumentSelection } from './documentselection.js';
import { History } from './history.js';
import { ModelRootElement } from './rootelement.js';
import { CKEditorError, Collection, EmitterMixin, isInsideSurrogatePair, isInsideCombinedSymbol } from '@ckeditor/ckeditor5-utils';
import { clone } from 'es-toolkit/compat';
// @if CK_DEBUG_ENGINE // const { logDocument } = require( '../dev-utils/utils' );
const graveyardName = '$graveyard';
/**
* Data model's document. It contains the model's structure, its selection and the history of changes.
*
* Read more about working with the model in
* {@glink framework/architecture/editing-engine#model introduction to the the editing engine's architecture}.
*
* Usually, the document contains just one {@link module:engine/model/document~ModelDocument#roots root element}, so
* you can retrieve it by just calling {@link module:engine/model/document~ModelDocument#getRoot} without specifying its name:
*
* ```ts
* model.document.getRoot(); // -> returns the main root
* ```
*
* However, the document may contain multiple roots – e.g. when the editor has multiple editable areas
* (e.g. a title and a body of a message).
*/
export class ModelDocument extends /* #__PURE__ */ EmitterMixin() {
/**
* The {@link module:engine/model/model~Model model} that the document is a part of.
*/
model;
/**
* The document's history.
*/
history;
/**
* The selection in this document.
*/
selection;
/**
* A list of roots that are owned and managed by this document. Use {@link #createRoot}, {@link #getRoot} and
* {@link #getRootNames} to manipulate it.
*/
roots;
/**
* The model differ object. Its role is to buffer changes done on the model document and then calculate a diff of those changes.
*/
differ;
/**
* Defines whether the document is in a read-only mode.
*
* The user should not be able to change the data of a document that is read-only.
*
* @readonly
*/
isReadOnly;
/**
* Post-fixer callbacks registered to the model document.
*/
_postFixers;
/**
* A flag that indicates whether the selection has changed since last change block.
*/
_hasSelectionChangedFromTheLastChangeBlock;
/**
* Creates an empty document instance with no {@link #roots} (other than
* the {@link #graveyard graveyard root}).
*/
constructor(model) {
super();
this.model = model;
this.history = new History();
this.selection = new ModelDocumentSelection(this);
this.roots = new Collection({ idProperty: 'rootName' });
this.differ = new Differ(model.markers);
this.isReadOnly = false;
this._postFixers = new Set();
this._hasSelectionChangedFromTheLastChangeBlock = false;
// Graveyard tree root. Document always have a graveyard root, which stores removed nodes.
this.createRoot('$root', graveyardName);
// Then, still before an operation is applied on model, buffer the change in differ.
this.listenTo(model, 'applyOperation', (evt, args) => {
const operation = args[0];
if (operation.isDocumentOperation) {
this.differ.bufferOperation(operation);
}
}, { priority: 'high' });
// After the operation is applied, bump document's version and add the operation to the history.
this.listenTo(model, 'applyOperation', (evt, args) => {
const operation = args[0];
if (operation.isDocumentOperation) {
this.history.addOperation(operation);
}
}, { priority: 'low' });
// Listen to selection changes. If selection changed, mark it.
this.listenTo(this.selection, 'change', () => {
this._hasSelectionChangedFromTheLastChangeBlock = true;
});
// Buffer marker changes.
// This is not covered in buffering operations because markers may change outside of them (when they
// are modified using `model.markers` collection, not through `MarkerOperation`).
this.listenTo(model.markers, 'update', (evt, marker, oldRange, newRange, oldMarkerData) => {
// Copy the `newRange` to the new marker data as during the marker removal the range is not updated.
const newMarkerData = { ...marker.getData(), range: newRange };
// Whenever marker is updated, buffer that change.
this.differ.bufferMarkerChange(marker.name, oldMarkerData, newMarkerData);
if (oldRange === null) {
// If this is a new marker, add a listener that will buffer change whenever marker changes.
marker.on('change', (evt, oldRange) => {
const markerData = marker.getData();
this.differ.bufferMarkerChange(marker.name, { ...markerData, range: oldRange }, markerData);
});
}
});
// This is a solution for a problem that may occur during real-time editing. If one client detached a root and another added
// something there at the same moment, the OT does not solve this problem currently. In such situation, the added elements would
// stay in the detached root.
//
// This is incorrect, a detached root should be empty and all elements from it should be removed. To solve this, the post-fixer will
// remove any element that is left in a detached root.
//
// Similarly, markers that are created at the beginning or at the end of the detached root will not be removed as well.
//
// The drawback of this solution over the OT solution is that the elements removed by the post-fixer will never be brought back.
// If the root detachment gets undone (and the root is brought back), the removed elements will not be there.
this.registerPostFixer(writer => {
let result = false;
for (const root of this.roots) {
if (!root.isAttached() && !root.isEmpty) {
writer.remove(writer.createRangeIn(root));
result = true;
}
}
for (const marker of this.model.markers) {
if (!marker.getRange().root.isAttached()) {
writer.removeMarker(marker);
result = true;
}
}
return result;
});
}
/**
* The document version. Every applied operation increases the version number. It is used to
* ensure that operations are applied on a proper document version.
*
* This property is equal to {@link module:engine/model/history~History#version `model.Document#history#version`}.
*
* If the {@link module:engine/model/operation/operation~Operation#baseVersion base version} does not match the document version,
* a {@link module:utils/ckeditorerror~CKEditorError model-document-applyoperation-wrong-version} error is thrown.
*/
get version() {
return this.history.version;
}
set version(version) {
this.history.version = version;
}
/**
* The graveyard tree root. A document always has a graveyard root that stores removed nodes.
*/
get graveyard() {
return this.getRoot(graveyardName);
}
/**
* Creates a new root.
*
* **Note:** do not use this method after the editor has been initialized! If you want to dynamically add a root, use
* {@link module:engine/model/writer~ModelWriter#addRoot `model.Writer#addRoot`} instead.
*
* @param elementName The element name. Defaults to `'$root'` which also has some basic schema defined
* (e.g. `$block` elements are allowed inside the `$root`). Make sure to define a proper schema if you use a different name.
* @param rootName A unique root name.
* @returns The created root.
*/
createRoot(elementName = '$root', rootName = 'main') {
if (this.roots.get(rootName)) {
/**
* A root with the specified name already exists.
*
* @error model-document-createroot-name-exists
*/
throw new CKEditorError('model-document-createroot-name-exists', this, { name: rootName });
}
const root = new ModelRootElement(this, elementName, rootName);
this.roots.add(root);
return root;
}
/**
* Removes all event listeners set by the document instance.
*/
destroy() {
this.selection.destroy();
this.stopListening();
}
/**
* Returns a root by its name.
*
* Detached roots are returned by this method. This is to be able to operate on the detached root (for example, to be able to create
* a position inside such a root for undo feature purposes).
*
* @param name The root name of the root to return.
* @returns The root registered under a given name or `null` when there is no root with the given name.
*/
getRoot(name = 'main') {
return this.roots.get(name);
}
/**
* Returns an array with names of all roots added to the document (except the {@link #graveyard graveyard root}).
*
* Detached roots **are not** returned by this method by default. This is to make sure that all features or algorithms that operate
* on the document data know which roots are still a part of the document and should be processed.
*
* @param includeDetached Specified whether detached roots should be returned as well.
*/
getRootNames(includeDetached = false) {
return this.getRoots(includeDetached).map(root => root.rootName);
}
/**
* Returns an array with all roots added to the document (except the {@link #graveyard graveyard root}).
*
* Detached roots **are not** returned by this method by default. This is to make sure that all features or algorithms that operate
* on the document data know which roots are still a part of the document and should be processed.
*
* @param includeDetached Specified whether detached roots should be returned as well.
*/
getRoots(includeDetached = false) {
return this.roots.filter(root => root != this.graveyard && (includeDetached || root.isAttached()) && root._isLoaded);
}
/**
* Used to register a post-fixer callback. A post-fixer mechanism guarantees that the features
* will operate on a correct model state.
*
* An execution of a feature may lead to an incorrect document tree state. The callbacks are used to fix the document tree after
* it has changed. Post-fixers are fired just after all changes from the outermost change block were applied but
* before the {@link module:engine/model/document~ModelDocument#event:change change event} is fired. If a post-fixer callback made
* a change, it should return `true`. When this happens, all post-fixers are fired again to check if something else should
* not be fixed in the new document tree state.
*
* As a parameter, a post-fixer callback receives a {@link module:engine/model/writer~ModelWriter writer} instance connected with the
* executed changes block. Thanks to that, all changes done by the callback will be added to the same
* {@link module:engine/model/batch~Batch batch} (and undo step) as the original changes. This makes post-fixer changes transparent
* for the user.
*
* An example of a post-fixer is a callback that checks if all the data were removed from the editor. If so, the
* callback should add an empty paragraph so that the editor is never empty:
*
* ```ts
* document.registerPostFixer( writer => {
* const changes = document.differ.getChanges();
*
* // Check if the changes lead to an empty root in the editor.
* for ( const entry of changes ) {
* if ( entry.type == 'remove' && entry.position.root.isEmpty ) {
* writer.insertElement( 'paragraph', entry.position.root, 0 );
*
* // It is fine to return early, even if multiple roots would need to be fixed.
* // All post-fixers will be fired again, so if there are more empty roots, those will be fixed, too.
* return true;
* }
* }
*
* return false;
* } );
* ```
*/
registerPostFixer(postFixer) {
this._postFixers.add(postFixer);
}
/**
* A custom `toJSON()` method to solve child-parent circular dependencies.
*
* @returns A clone of this object with the document property changed to a string.
*/
toJSON() {
const json = clone(this);
// Due to circular references we need to remove parent reference.
json.selection = '[engine.model.DocumentSelection]';
json.model = '[engine.model.Model]';
return json;
}
/**
* Check if there were any changes done on document, and if so, call post-fixers,
* fire `change` event for features and conversion and then reset the differ.
* Fire `change:data` event when at least one operation or buffered marker changes the data.
*
* @internal
* @fires change
* @fires change:data
* @param writer The writer on which post-fixers will be called.
*/
_handleChangeBlock(writer) {
if (this._hasDocumentChangedFromTheLastChangeBlock()) {
this._callPostFixers(writer);
// Refresh selection attributes according to the final position in the model after the change.
this.selection.refresh();
if (this.differ.hasDataChanges()) {
this.fire('change:data', writer.batch);
}
else {
this.fire('change', writer.batch);
}
// Theoretically, it is not necessary to refresh selection after change event because
// post-fixers are the last who should change the model, but just in case...
this.selection.refresh();
this.differ.reset();
}
this._hasSelectionChangedFromTheLastChangeBlock = false;
}
/**
* Returns whether there is a buffered change or if the selection has changed from the last
* {@link module:engine/model/model~Model#enqueueChange `enqueueChange()` block}
* or {@link module:engine/model/model~Model#change `change()` block}.
*
* @returns Returns `true` if document has changed from the last `change()` or `enqueueChange()` block.
*/
_hasDocumentChangedFromTheLastChangeBlock() {
return !this.differ.isEmpty || this._hasSelectionChangedFromTheLastChangeBlock;
}
/**
* Returns the default root for this document which is either the first root that was added to the document using
* {@link #createRoot} or the {@link #graveyard graveyard root} if no other roots were created.
*
* @returns The default root for this document.
*/
_getDefaultRoot() {
const roots = this.getRoots();
return roots.length ? roots[0] : this.graveyard;
}
/**
* Returns the default range for this selection. The default range is a collapsed range that starts and ends
* at the beginning of this selection's document {@link #_getDefaultRoot default root}.
*
* @internal
*/
_getDefaultRange() {
const defaultRoot = this._getDefaultRoot();
const model = this.model;
const schema = model.schema;
// Find the first position where the selection can be put.
const position = model.createPositionFromPath(defaultRoot, [0]);
const nearestRange = schema.getNearestSelectionRange(position);
// If valid selection range is not found - return range collapsed at the beginning of the root.
return nearestRange || model.createRange(position);
}
/**
* Checks whether a given {@link module:engine/model/range~ModelRange range} is a valid range for
* the {@link #selection document's selection}.
*
* @internal
* @param range A range to check.
* @returns `true` if `range` is valid, `false` otherwise.
*/
_validateSelectionRange(range) {
return range.start.isValid() && range.end.isValid() &&
validateTextNodePosition(range.start) && validateTextNodePosition(range.end);
}
/**
* Performs post-fixer loops. Executes post-fixer callbacks as long as none of them has done any changes to the model.
*
* @param writer The writer on which post-fixer callbacks will be called.
*/
_callPostFixers(writer) {
let wasFixed = false;
do {
for (const callback of this._postFixers) {
// Ensure selection attributes are up to date before each post-fixer.
// https://github.com/ckeditor/ckeditor5-engine/issues/1673.
//
// It might be good to refresh the selection after each operation but at the moment it leads
// to losing attributes for composition or and spell checking
// https://github.com/ckeditor/ckeditor5-typing/issues/188
this.selection.refresh();
wasFixed = callback(writer);
if (wasFixed) {
break;
}
}
} while (wasFixed);
}
}
/**
* Checks whether given range boundary position is valid for document selection, meaning that is not between
* unicode surrogate pairs or base character and combining marks.
*/
function validateTextNodePosition(rangeBoundary) {
const textNode = rangeBoundary.textNode;
if (textNode) {
const data = textNode.data;
const offset = rangeBoundary.offset - textNode.startOffset;
return !isInsideSurrogatePair(data, offset) && !isInsideCombinedSymbol(data, offset);
}
return true;
}