monaco-semantic-highlighting-service.ts

/********************************************************************************
 * Copyright (C) 2018 TypeFox and others.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the Eclipse
 * Public License v. 2.0 are satisfied: GNU General Public License, version 2
 * with the GNU Classpath Exception which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 ********************************************************************************/

import { inject, injectable } from 'inversify';
import URI from '@theia/core/lib/common/uri';
import { ILogger } from '@theia/core/lib/common/logger';
import { EditorManager } from '@theia/editor/lib/browser/editor-manager';
import { Disposable, DisposableCollection } from '@theia/core/lib/common/disposable';
import { EditorDecoration, EditorDecorationOptions } from '@theia/editor/lib/browser/decorations';
import { SemanticHighlightingService, SemanticHighlightingRange, Range } from '@theia/editor/lib/browser/semantic-highlight/semantic-highlighting-service';
import { MonacoEditor } from './monaco-editor';

@injectable()
export class MonacoSemanticHighlightingService extends SemanticHighlightingService {

    @inject(ILogger)
    protected readonly logger: ILogger;

    @inject(EditorManager)
    protected readonly editorManager: EditorManager;

    protected readonly decorations = new Map<string, Set<string>>();
    protected readonly toDisposeOnEditorClose = new Map<string, Disposable>();

    async decorate(languageId: string, uri: URI, ranges: SemanticHighlightingRange[]): Promise<void> {
        const editor = await this.editor(uri);
        if (!editor) {
            return;
        }

        const key = uri.toString();
        if (!this.toDisposeOnEditorClose.has(key)) {
            this.toDisposeOnEditorClose.set(key, new DisposableCollection(
                editor.onDispose(() => this.deleteDecorations(key, editor))
            ));
        }

        const newDecorations = ranges.map(range => this.toDecoration(languageId, range));
        const oldDecorations = this.oldDecorations(key, editor, ranges);
        const newState = editor.deltaDecorations({
            newDecorations,
            oldDecorations
        });

        const decorationIds = this.decorationIds(key);
        newState.forEach(id => decorationIds.add(id));
        this.decorations.set(key, decorationIds);
    }

    dispose(): void {
        Array.from(this.toDisposeOnEditorClose.values()).forEach(disposable => disposable.dispose());
    }

    protected decorationIds(uri: string | URI): Set<string> {
        return this.decorations.get(typeof uri === 'string' ? uri : uri.toString()) || new Set();
    }

    protected async editor(uri: string | URI): Promise<MonacoEditor | undefined> {
        const editorWidget = await this.editorManager.getByUri(typeof uri === 'string' ? new URI(uri) : uri);
        if (!!editorWidget && editorWidget.editor instanceof MonacoEditor) {
            return editorWidget.editor;
        }
        return undefined;
    }

    protected async model(uri: string | URI): Promise<monaco.editor.ITextModel | undefined> {
        const editor = await this.editor(uri);
        if (editor) {
            return editor.getControl().getModel();
        }
        return undefined;
    }

    /**
     * Returns all the semantic highlighting decoration IDs that are affected by any of the range arguments.
     */
    protected oldDecorations(uri: string, editor: MonacoEditor, ranges: SemanticHighlightingRange[]): string[] {
        const ids = this.decorationIds(uri);
        const affectedLines = Array.from(new Set(ranges.map(r => [r.start.line, r.end.line]).reduce((prev, curr) => prev.concat(curr), [])));
        return affectedLines
            .map(line => editor.getLinesDecorations(line, line))
            .reduce((prev, curr) => prev.concat(curr), [])
            .map(decoration => decoration.id)
            .filter(id => ids.has(id));
    }

    protected deleteDecorations(uri: string, editor: MonacoEditor): void {
        const ids = this.decorations.get(uri);
        if (ids) {
            const oldDecorations = Array.from(ids);
            editor.deltaDecorations({
                newDecorations: [],
                oldDecorations
            });
            this.decorations.delete(uri);
        }
        const disposable = this.toDisposeOnEditorClose.get(uri);
        if (disposable) {
            disposable.dispose();
        }
        this.toDisposeOnEditorClose.delete(uri);
    }

    protected toDecoration(languageId: string, range: SemanticHighlightingRange): EditorDecoration {
        const { start, end } = range;
        const scopes = range.scope !== undefined ? this.scopesFor(languageId, range.scope) : [];
        const options = this.toOptions(scopes);
        return {
            range: Range.create(start, end),
            options
        };
    }

    protected toOptions(scopes: string[]): EditorDecorationOptions {
        // TODO: why for-of? How to pick the right scope? Is it fine to get the first element (with the narrowest scope)?
        for (const scope of scopes) {
            const metadata = this.tokenTheme().match(undefined, scope);
            const inlineClassName = monaco.modes.TokenMetadata.getClassNameFromMetadata(metadata);
            return {
                inlineClassName
            };
        }
        return {};
    }

    protected tokenTheme(): monaco.services.TokenTheme {
        return monaco.services.StaticServices.standaloneThemeService.get().getTheme().tokenTheme;
    }

}