Create basic theme service

Part of #4184

src/browser/services/Services.ts

@@ -5,10 +5,11 @@
 
 import { IEvent } from 'common/EventEmitter';
 import { IRenderDimensions, IRenderer } from 'browser/renderer/shared/Types';
-import { IColorSet } from 'browser/Types';
+import { IColorSet, ReadonlyColorSet } from 'browser/Types';
 import { ISelectionRedrawRequestEvent as ISelectionRequestRedrawEvent, ISelectionRequestScrollLinesEvent } from 'browser/selection/Types';
 import { createDecorator } from 'common/services/ServiceRegistry';
-import { IDisposable } from 'common/Types';
+import { ColorIndex, IDisposable } from 'common/Types';
+import { ITheme } from 'common/services/Services';
 
 export const ICharSizeService = createDecorator<ICharSizeService>('CharSizeService');
 export interface ICharSizeService {
@@ -73,7 +74,7 @@ export interface IRenderService extends IDisposable {
   resize(cols: number, rows: number): void;
   hasRenderer(): boolean;
   setRenderer(renderer: IRenderer): void;
-  setColors(colors: IColorSet): void;
+  setColors(colors: ReadonlyColorSet): void;
   handleDevicePixelRatioChange(): void;
   handleResize(cols: number, rows: number): void;
   handleCharSizeChanged(): void;
@@ -121,3 +122,17 @@ export interface ICharacterJoinerService {
   deregister(joinerId: number): boolean;
   getJoinedCharacters(row: number): [number, number][];
 }
+
+export const IThemeService = createDecorator<IThemeService>('ThemeService');
+export interface IThemeService {
+  serviceBrand: undefined;
+
+  readonly colors: ReadonlyColorSet;
+  setTheme(theme?: ITheme): void;
+  restoreColor(slot?: ColorIndex): void;
+  /**
+   * Allows external modifying of colors in the theme, this is used instead of {@link colors} to
+   * prevent accidental writes.
+   */
+  modifyColors(callback: (colors: IColorSet) => void): void;
+}

src/browser/services/ThemeService.ts

@@ -0,0 +1,46 @@
+/**
+ * Copyright (c) 2022 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ColorManager } from 'browser/ColorManager';
+import { IThemeService } from 'browser/services/Services';
+import { IColorSet, ReadonlyColorSet } from 'browser/Types';
+import { Disposable } from 'common/Lifecycle';
+import { IOptionsService, ITheme } from 'common/services/Services';
+import { ColorIndex } from 'common/Types';
+
+export class ThemeService extends Disposable implements IThemeService {
+  public serviceBrand: undefined;
+
+  // TODO: Merge color manager into theme service
+  private _colorManager = new ColorManager();
+
+  public get colors(): ReadonlyColorSet { return this._colorManager.colors; }
+
+  constructor(
+    @IOptionsService private readonly _optionsService: IOptionsService
+  ) {
+    super();
+    this.register(this._optionsService.onOptionChange(key => {
+      if (key === 'theme') {
+        this.setTheme(this._optionsService.rawOptions.theme);
+      }
+      this._colorManager.handleOptionsChange(key, this._optionsService.rawOptions[key]);
+    }));
+    this._colorManager.setTheme(this._optionsService.rawOptions.theme);
+  }
+
+  public setTheme(theme: ITheme = {}): void {
+    this._colorManager.setTheme(theme);
+  }
+
+  public restoreColor(slot?: ColorIndex): void {
+    this._colorManager.restoreColor(slot);
+  }
+
+  public modifyColors(callback: (colors: IColorSet) => void): void {
+    callback(this._colorManager.colors);
+    // TODO: Fire event
+  }
+}