[theming] #4831: color contribution point

- Theia extensions can register new colors
- All colors are translated into css variables with `.` replaced by `-` and `--theia` prefix
- Theia extensions can use registered colors via css or programatically from `ColorRegistrsy.getCurrentColor`

Signed-off-by: Anton Kosyakov <anton.kosyakov@typefox.io>

packages/core/src/browser/color-application-contribution.ts

@@ -0,0 +1,75 @@
+/********************************************************************************
+ * Copyright (C) 2019 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 { injectable, inject, named } from 'inversify';
+import { ColorRegistry } from './color-registry';
+import { Emitter } from '../common/event';
+import { ThemeService } from './theming';
+import { FrontendApplicationContribution } from './frontend-application';
+import { ContributionProvider } from '../common/contribution-provider';
+import { Disposable, DisposableCollection } from '../common/disposable';
+
+export const ColorContribution = Symbol('ColorContribution');
+export interface ColorContribution {
+    registerColors(colors: ColorRegistry): void;
+}
+
+@injectable()
+export class ColorApplicationContribution implements FrontendApplicationContribution {
+
+    protected readonly onDidChangeEmitter = new Emitter<void>();
+    readonly onDidChange = this.onDidChangeEmitter.event;
+
+    @inject(ColorRegistry)
+    protected readonly colors: ColorRegistry;
+
+    @inject(ContributionProvider) @named(ColorContribution)
+    protected readonly colorContributions: ContributionProvider<ColorContribution>;
+
+    onStart(): void {
+        for (const contribution of this.colorContributions.getContributions()) {
+            contribution.registerColors(this.colors);
+        }
+
+        this.update();
+        ThemeService.get().onThemeChange(() => this.update());
+    }
+
+    protected readonly toUpdate = new DisposableCollection();
+    protected update(): void {
+        if (!document) {
+            return;
+        }
+        this.toUpdate.dispose();
+        const theme = 'theia-' + ThemeService.get().getCurrentTheme().type;
+        document.body.classList.add(theme);
+        this.toUpdate.push(Disposable.create(() => document.body.classList.remove(theme)));
+
+        const documentElement = document.documentElement;
+        if (documentElement) {
+            for (const id of this.colors.getColors()) {
+                const color = this.colors.getCurrentColor(id);
+                if (color) {
+                    const propertyName = `--theia-${id.replace('.', '-')}`;
+                    documentElement.style.setProperty(propertyName, color);
+                    this.toUpdate.push(Disposable.create(() => documentElement.style.removeProperty(propertyName)));
+                }
+            }
+        }
+        this.onDidChangeEmitter.fire(undefined);
+    }
+
+}

packages/core/src/browser/color-registry.ts

@@ -15,6 +15,18 @@
  ********************************************************************************/
 
 import { injectable } from 'inversify';
+import { Disposable } from '../common/disposable';
+
+export interface ColorDefaults {
+    light?: string
+    dark?: string
+    hc?: string
+}
+
+export interface ColorOptions {
+    defaults?: ColorDefaults
+    description: string
+}
 
 /**
  * It should be implemented by an extension, e.g. by the monaco extension.
@@ -28,4 +40,8 @@ export class ColorRegistry {
         return undefined;
     }
 
+    register(id: string, options: ColorOptions): Disposable {
+        return Disposable.NULL;
+    }
+
 }

packages/core/src/browser/frontend-application-module.ts

@@ -84,14 +84,19 @@ import { TabBarDecoratorService, TabBarDecorator } from './shell/tab-bar-decorat
 import { ContextMenuContext } from './menu/context-menu-context';
 import { bindResourceProvider, bindMessageService, bindPreferenceService } from './frontend-application-bindings';
 import { ColorRegistry } from './color-registry';
+import { ColorContribution, ColorApplicationContribution } from './color-application-contribution';
 
 export { bindResourceProvider, bindMessageService, bindPreferenceService };
 
 export const frontendApplicationModule = new ContainerModule((bind, unbind, isBound, rebind) => {
     const themeService = ThemeService.get();
     themeService.register(...BuiltinThemeProvider.themes);
     themeService.startupTheme();
+
     bind(ColorRegistry).toSelf().inSingletonScope();
+    bindContributionProvider(bind, ColorContribution);
+    bind(ColorApplicationContribution).toSelf().inSingletonScope();
+    bind(FrontendApplicationContribution).toService(ColorApplicationContribution);
 
     bind(FrontendApplication).toSelf().inSingletonScope();
     bind(FrontendApplicationStateService).toSelf().inSingletonScope();

packages/monaco/src/browser/monaco-color-registry.ts

@@ -15,7 +15,8 @@
  ********************************************************************************/
 
 import { injectable } from 'inversify';
-import { ColorRegistry } from '@theia/core/lib/browser/color-registry';
+import { ColorRegistry, ColorOptions } from '@theia/core/lib/browser/color-registry';
+import { Disposable } from '@theia/core/lib/common/disposable';
 
 @injectable()
 export class MonacoColorRegistry implements ColorRegistry {
@@ -34,4 +35,9 @@ export class MonacoColorRegistry implements ColorRegistry {
         return color && color.toString();
     }
 
+    register(id: string, options: ColorOptions): Disposable {
+        const identifier = this.monacoColorRegistry.registerColor(id, options.defaults, options.description);
+        return Disposable.create(() => this.monacoColorRegistry.deregisterColor(identifier));
+    }
+
 }

packages/monaco/src/typings/monaco/index.d.ts

@@ -542,8 +542,15 @@ declare module monaco.color {
     export interface ColorContribution {
         readonly id: string;
     }
+    export interface ColorDefaults {
+        ligh?: string;
+        dark?: string;
+        hc?: string;
+    }
     export interface IColorRegistry {
         getColors(): ColorContribution[];
+        registerColor(id: string, defaults: ColorDefaults | undefined, description: string): string;
+        deregisterColor(id: string): void;
     }
     export function getColorRegistry(): IColorRegistry;
 }

packages/plugin-ext/src/main/browser/webview/webview-theme-data-provider.ts

@@ -24,6 +24,7 @@ import { Emitter } from '@theia/core/lib/common/event';
 import { EditorPreferences, EditorConfiguration } from '@theia/editor/lib/browser/editor-preferences';
 import { ThemeService } from '@theia/core/lib/browser/theming';
 import { ColorRegistry } from '@theia/core/lib/browser/color-registry';
+import { ColorApplicationContribution } from '@theia/core/lib/browser/color-application-contribution';
 
 export type WebviewThemeType = 'vscode-light' | 'vscode-dark' | 'vscode-high-contrast';
 export interface WebviewThemeData {
@@ -43,6 +44,9 @@ export class WebviewThemeDataProvider {
     @inject(ColorRegistry)
     protected readonly colorRegistry: ColorRegistry;
 
+    @inject(ColorApplicationContribution)
+    protected readonly colorContribution: ColorApplicationContribution;
+
     protected themeData: WebviewThemeData | undefined;
 
     protected readonly editorStyles = new Map<keyof EditorConfiguration, string>([
@@ -53,7 +57,7 @@ export class WebviewThemeDataProvider {
 
     @postConstruct()
     protected init(): void {
-        ThemeService.get().onThemeChange(() => this.reset());
+        this.colorContribution.onDidChange(() => this.reset());
 
         this.editorPreferences.onPreferenceChanged(e => {
             if (this.editorStyles.has(e.preferenceName)) {