ckeditor/ckeditor5-core

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src/plugincollection.js

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/**
 * @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 core/plugincollection
 */

/* globals console */

import CKEditorError, { attachLinkToDocumentation } from '@ckeditor/ckeditor5-utils/src/ckeditorerror';

import EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';
import mix from '@ckeditor/ckeditor5-utils/src/mix';

/**
 * Manages a list of CKEditor plugins, including loading, resolving dependencies and initialization.
 *
 * @mixes module:utils/emittermixin~EmitterMixin
 */
export default class PluginCollection {
    /**
     * Creates an instance of the plugin collection class.
     * Allows loading and initializing plugins and their dependencies.
     * Allows to provide a list of already loaded plugins. These plugins will not be destroyed along with this collection.
     *
     * @param {module:core/editor/editor~Editor|module:core/context~Context} context
     * @param {Array.<Function>} [availablePlugins] Plugins (constructors) which the collection will be able to use
     * when {@link module:core/plugincollection~PluginCollection#init} is used with plugin names (strings, instead of constructors).
     * Usually, the editor will pass its built-in plugins to the collection so they can later be
     * used in `config.plugins` or `config.removePlugins` by names.
     * @param {Iterable.<Array>} contextPlugins A list of already initialized plugins represented by a
     * `[ PluginConstructor, pluginInstance ]` pair.
     */
    constructor( context, availablePlugins = [], contextPlugins = [] ) {
        /**
         * @protected
         * @type {module:core/editor/editor~Editor|module:core/context~Context}
         */
        this._context = context;

        /**
         * @protected
         * @type {Map}
         */
        this._plugins = new Map();

        /**
         * A map of plugin constructors that can be retrieved by their names.
         *
         * @protected
         * @type {Map.<String|Function,Function>}
         */
        this._availablePlugins = new Map();

        for ( const PluginConstructor of availablePlugins ) {
            if ( PluginConstructor.pluginName ) {
                this._availablePlugins.set( PluginConstructor.pluginName, PluginConstructor );
            }
        }

        /**
         * Map of {@link module:core/contextplugin~ContextPlugin context plugins} which can be retrieved by their constructors or instances.
         *
         * @protected
         * @type {Map<Function,Function>}
         */
        this._contextPlugins = new Map();

        for ( const [ PluginConstructor, pluginInstance ] of contextPlugins ) {
            this._contextPlugins.set( PluginConstructor, pluginInstance );
            this._contextPlugins.set( pluginInstance, PluginConstructor );

            // To make it possible to require a plugin by its name.
            if ( PluginConstructor.pluginName ) {
                this._availablePlugins.set( PluginConstructor.pluginName, PluginConstructor );
            }
        }
    }

    /**
     * Iterable interface.
     *
     * Returns `[ PluginConstructor, pluginInstance ]` pairs.
     *
     * @returns {Iterable.<Array>}
     */
    * [ Symbol.iterator ]() {
        for ( const entry of this._plugins ) {
            if ( typeof entry[ 0 ] == 'function' ) {
                yield entry;
            }
        }
    }

    /**
     * Gets the plugin instance by its constructor or name.
     *
     *        // Check if 'Clipboard' plugin was loaded.
     *        if ( editor.plugins.has( 'Clipboard' ) ) {
     *            // Get clipboard plugin instance
     *            const clipboard = editor.plugins.get( 'Clipboard' );
     *
     *            this.listenTo( clipboard, 'inputTransformation', ( evt, data ) => {
     *                // Do something on clipboard input.
     *            } );
     *        }
     *
     * **Note**: This method will throw error if plugin is not loaded. Use `{@link #has editor.plugins.has()}`
     * to check if plugin is available.
     *
     * @param {Function|String} key The plugin constructor or {@link module:core/plugin~PluginInterface.pluginName name}.
     * @returns {module:core/plugin~PluginInterface}
     */
    get( key ) {
        const plugin = this._plugins.get( key );

        if ( !plugin ) {
            /**
             * The plugin is not loaded and could not be obtained.
             *
             * Plugin classes (constructors) need to be provided to the editor and must be loaded before they can be obtained from
             * the plugin collection.
             * This is usually done in CKEditor 5 builds by setting the {@link module:core/editor/editor~Editor.builtinPlugins}
             * property.
             *
             * **Note**: You can use `{@link module:core/plugincollection~PluginCollection#has editor.plugins.has()}`
             * to check if plugin was loaded.
             *
             * @error plugincollection-plugin-not-loaded
             * @param {String} plugin The name of the plugin which is not loaded.
             */
            const errorMsg = 'plugincollection-plugin-not-loaded: The requested plugin is not loaded.';

            let pluginName = key;

            if ( typeof key == 'function' ) {
                pluginName = key.pluginName || key.name;
            }

            throw new CKEditorError( errorMsg, this._context, { plugin: pluginName } );
        }

        return plugin;
    }

    /**
     * Checks if a plugin is loaded.
     *
     *        // Check if the 'Clipboard' plugin was loaded.
     *        if ( editor.plugins.has( 'Clipboard' ) ) {
     *            // Now use the clipboard plugin instance:
     *            const clipboard = editor.plugins.get( 'Clipboard' );
     *
     *            // ...
     *        }
     *
     * @param {Function|String} key The plugin constructor or {@link module:core/plugin~PluginInterface.pluginName name}.
     * @returns {Boolean}
     */
    has( key ) {
        return this._plugins.has( key );
    }

    /**
     * Initializes a set of plugins and adds them to the collection.
     *
     * @param {Array.<Function|String>} plugins An array of {@link module:core/plugin~PluginInterface plugin constructors}
     * or {@link module:core/plugin~PluginInterface.pluginName plugin names}. The second option (names) works only if
     * `availablePlugins` were passed to the {@link #constructor}.
     * @param {Array.<String|Function>} [removePlugins] Names of plugins or plugin constructors
     * that should not be loaded (despite being specified in the `plugins` array).
     * @returns {Promise.<module:core/plugin~LoadedPlugins>} A promise which gets resolved once all plugins are loaded
     * and available in the collection.
     */
    init( plugins, removePlugins = [] ) {
        const that = this;
        const context = this._context;
        const loading = new Set();
        const loaded = [];

        const pluginConstructors = mapToAvailableConstructors( plugins );
        const removePluginConstructors = mapToAvailableConstructors( removePlugins );
        const missingPlugins = getMissingPluginNames( plugins );

        if ( missingPlugins ) {
            /**
             * Some plugins are not available and could not be loaded.
             *
             * Plugin classes (constructors) need to be provided to the editor before they can be loaded by name.
             * This is usually done in CKEditor 5 builds by setting the {@link module:core/editor/editor~Editor.builtinPlugins}
             * property.
             *
             * **If you see this warning when using one of the {@glink builds/index CKEditor 5 Builds}**, it means
             * that you try to enable a plugin which was not included in that build. This may be due to a typo
             * in the plugin name or simply because that plugin is not a part of this build. In the latter scenario,
             * read more about {@glink builds/guides/development/custom-builds custom builds}.
             *
             * **If you see this warning when using one of the editor creators directly** (not a build), then it means
             * that you tried loading plugins by name. However, unlike CKEditor 4, CKEditor 5 does not implement a "plugin loader".
             * This means that CKEditor 5 does not know where to load the plugin modules from. Therefore, you need to
             * provide each plugin through reference (as a constructor function). Check out the examples in
             * {@glink builds/guides/integration/advanced-setup#scenario-2-building-from-source "Building from source"}.
             *
             * @error plugincollection-plugin-not-found
             * @param {Array.<String>} plugins The name of the plugins which could not be loaded.
             */
            const errorMsg = 'plugincollection-plugin-not-found: Some plugins are not available and could not be loaded.';

            // Log the error so it's more visible on the console. Hopefully, for better DX.
            console.error( attachLinkToDocumentation( errorMsg ), { plugins: missingPlugins } );

            return Promise.reject( new CKEditorError( errorMsg, context, { plugins: missingPlugins } ) );
        }

        return Promise.all( pluginConstructors.map( loadPlugin ) )
            .then( () => initPlugins( loaded, 'init' ) )
            .then( () => initPlugins( loaded, 'afterInit' ) )
            .then( () => loaded );

        function loadPlugin( PluginConstructor ) {
            if ( removePluginConstructors.includes( PluginConstructor ) ) {
                return;
            }

            // The plugin is already loaded or being loaded - do nothing.
            if ( that._plugins.has( PluginConstructor ) || loading.has( PluginConstructor ) ) {
                return;
            }

            return instantiatePlugin( PluginConstructor )
                .catch( err => {
                    /**
                     * It was not possible to load the plugin.
                     *
                     * This is a generic error logged to the console when a JavaSript error is thrown during the initialization
                     * of one of the plugins.
                     *
                     * If you correctly handled the promise returned by the editor's `create()` method (like shown below),
                     * you will find the original error logged to the console, too:
                     *
                     *        ClassicEditor.create( document.getElementById( 'editor' ) )
                     *            .then( editor => {
                     *                // ...
                     *             } )
                     *            .catch( error => {
                     *                console.error( error );
                     *            } );
                     *
                     * @error plugincollection-load
                     * @param {String} plugin The name of the plugin that could not be loaded.
                     */
                    console.error( attachLinkToDocumentation(
                        'plugincollection-load: It was not possible to load the plugin.'
                    ), { plugin: PluginConstructor } );

                    throw err;
                } );
        }

        function initPlugins( loadedPlugins, method ) {
            return loadedPlugins.reduce( ( promise, plugin ) => {
                if ( !plugin[ method ] ) {
                    return promise;
                }

                if ( that._contextPlugins.has( plugin ) ) {
                    return promise;
                }

                return promise.then( plugin[ method ].bind( plugin ) );
            }, Promise.resolve() );
        }

        function instantiatePlugin( PluginConstructor ) {
            return new Promise( resolve => {
                loading.add( PluginConstructor );

                if ( PluginConstructor.requires ) {
                    PluginConstructor.requires.forEach( RequiredPluginConstructorOrName => {
                        const RequiredPluginConstructor = getPluginConstructor( RequiredPluginConstructorOrName );

                        if ( PluginConstructor.isContextPlugin && !RequiredPluginConstructor.isContextPlugin ) {
                            /**
                             * If a plugin is a context plugin, all plugins it requires should also be context plugins
                             * instead of plugins. In other words, if one plugin can be used in the context,
                             * all its requirements should also be ready to be used in the context. Note that the context
                             * provides only a part of the API provided by the editor. If one plugin needs a full
                             * editor API, all plugins which require it are considered as plugins that need a full
                             * editor API.
                             *
                             * @error plugincollection-context-required
                             * @param {String} plugin The name of the required plugin.
                             * @param {String} requiredBy The name of the parent plugin.
                             */
                            throw new CKEditorError(
                                'plugincollection-context-required: Context plugin can not require plugin which is not a context plugin',
                                null,
                                { plugin: RequiredPluginConstructor.name, requiredBy: PluginConstructor.name }
                            );
                        }

                        if ( removePlugins.includes( RequiredPluginConstructor ) ) {
                            /**
                             * Cannot load a plugin because one of its dependencies is listed in the `removePlugins` option.
                             *
                             * @error plugincollection-required
                             * @param {String} plugin The name of the required plugin.
                             * @param {String} requiredBy The name of the parent plugin.
                             */
                            throw new CKEditorError(
                                'plugincollection-required: Cannot load a plugin because one of its dependencies is listed in' +
                                'the `removePlugins` option.',
                                context,
                                { plugin: RequiredPluginConstructor.name, requiredBy: PluginConstructor.name }
                            );
                        }

                        loadPlugin( RequiredPluginConstructor );
                    } );
                }

                const plugin = that._contextPlugins.get( PluginConstructor ) || new PluginConstructor( context );
                that._add( PluginConstructor, plugin );
                loaded.push( plugin );

                resolve();
            } );
        }

        function getPluginConstructor( PluginConstructorOrName ) {
            if ( typeof PluginConstructorOrName == 'function' ) {
                return PluginConstructorOrName;
            }

            return that._availablePlugins.get( PluginConstructorOrName );
        }

        function getMissingPluginNames( plugins ) {
            const missingPlugins = [];

            for ( const pluginNameOrConstructor of plugins ) {
                if ( !getPluginConstructor( pluginNameOrConstructor ) ) {
                    missingPlugins.push( pluginNameOrConstructor );
                }
            }

            return missingPlugins.length ? missingPlugins : null;
        }

        function mapToAvailableConstructors( plugins ) {
            return plugins
                .map( pluginNameOrConstructor => getPluginConstructor( pluginNameOrConstructor ) )
                .filter( PluginConstructor => !!PluginConstructor );
        }
    }

    /**
     * Destroys all loaded plugins.
     *
     * @returns {Promise}
     */
    destroy() {
        const promises = [];

        for ( const [ , pluginInstance ] of this ) {
            if ( typeof pluginInstance.destroy == 'function' && !this._contextPlugins.has( pluginInstance ) ) {
                promises.push( pluginInstance.destroy() );
            }
        }

        return Promise.all( promises );
    }

    /**
     * Adds the plugin to the collection. Exposed mainly for testing purposes.
     *
     * @protected
     * @param {Function} PluginConstructor The plugin constructor.
     * @param {module:core/plugin~PluginInterface} plugin The instance of the plugin.
     */
    _add( PluginConstructor, plugin ) {
        this._plugins.set( PluginConstructor, plugin );

        const pluginName = PluginConstructor.pluginName;

        if ( !pluginName ) {
            return;
        }

        if ( this._plugins.has( pluginName ) ) {
            /**
             * Two plugins with the same {@link module:core/plugin~PluginInterface.pluginName} were loaded.
             * This will lead to runtime conflicts between these plugins.
             *
             * In practice, this warning usually means that new plugins were added to an existing CKEditor 5 build.
             * Plugins should always be added to a source version of the editor (`@ckeditor/ckeditor5-editor-*`),
             * not to an editor imported from one of the `@ckeditor/ckeditor5-build-*` packages.
             *
             * Check your import paths and the list of plugins passed to
             * {@link module:core/editor/editor~Editor.create `Editor.create()`}
             * or specified in {@link module:core/editor/editor~Editor.builtinPlugins `Editor.builtinPlugins`}.
             *
             * The second option is that your `node_modules/` directory contains duplicated versions of the same
             * CKEditor 5 packages. Normally, on clean installations, npm deduplicates packages in `node_modules/`, so
             * it may be enough to call `rm -rf node_modules && npm i`. However, if you installed conflicting versions
             * of packages, their dependencies may need to be installed in more than one version which may lead to this
             * warning.
             *
             * Technically speaking, this error occurs because after adding a plugin to an existing editor build
             * dependencies of this plugin are being duplicated.
             * They are already built into that editor build and now get added for the second time as dependencies
             * of the plugin you are installing.
             *
             * Read more about {@glink builds/guides/integration/installing-plugins installing plugins}.
             *
             * @error plugincollection-plugin-name-conflict
             * @param {String} pluginName The duplicated plugin name.
             * @param {Function} plugin1 The first plugin constructor.
             * @param {Function} plugin2 The second plugin constructor.
             */
            throw new CKEditorError(
                'plugincollection-plugin-name-conflict: Two plugins with the same name were loaded.',
                null,
                { pluginName, plugin1: this._plugins.get( pluginName ).constructor, plugin2: PluginConstructor }
            );
        }

        this._plugins.set( pluginName, plugin );
    }
}

mix( PluginCollection, EmitterMixin );