Create 2 and 4 key map objects, use in color and glyph caches

src/browser/ColorContrastCache.ts

@@ -5,35 +5,30 @@
 
 import { IColorContrastCache } from 'browser/Types';
 import { IColor } from 'common/Types';
+import { TwoKeyMap } from 'common/MultiKeyMap';
 
 export class ColorContrastCache implements IColorContrastCache {
-  private _color: { [bg: number]: { [fg: number]: IColor | null | undefined } | undefined } = {};
-  private _rgba: { [bg: number]: { [fg: number]: string | null | undefined } | undefined } = {};
-
-  public clear(): void {
-    this._color = {};
-    this._rgba = {};
-  }
+  private _color: TwoKeyMap</* bg */number, /* fg */number, IColor | null> = new TwoKeyMap();
+  private _css: TwoKeyMap</* bg */number, /* fg */number, string | null> = new TwoKeyMap();
 
   public setCss(bg: number, fg: number, value: string | null): void {
-    if (!this._rgba[bg]) {
-      this._rgba[bg] = {};
-    }
-    this._rgba[bg]![fg] = value;
+    this._css.set(bg, fg, value);
   }
 
   public getCss(bg: number, fg: number): string | null | undefined {
-    return this._rgba[bg] ? this._rgba[bg]![fg] : undefined;
+    return this._css.get(bg, fg);
   }
 
   public setColor(bg: number, fg: number, value: IColor | null): void {
-    if (!this._color[bg]) {
-      this._color[bg] = {};
-    }
-    this._color[bg]![fg] = value;
+    this._color.set(bg, fg, value);
   }
 
   public getColor(bg: number, fg: number): IColor | null | undefined {
-    return this._color[bg] ? this._color[bg]![fg] : undefined;
+    return this._color.get(bg, fg);
+  }
+
+  public clear(): void {
+    this._color.clear();
+    this._css.clear();
   }
 }

src/common/MultiKeyMap.ts

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2022 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+export class TwoKeyMap<TFirst extends string | number, TSecond extends string | number, TValue> {
+  private _data: { [bg: string | number]: { [fg: string | number]: TValue | undefined } | undefined } = {};
+
+  public set(first: TFirst, second: TSecond, value: TValue): void {
+    if (!this._data[first]) {
+      this._data[first] = {};
+    }
+    this._data[first as string | number]![second] = value;
+  }
+
+  public get(first: TFirst, second: TSecond): TValue | undefined {
+    return this._data[first as string | number] ? this._data[first as string | number]![second] : undefined;
+  }
+
+  public clear(): void {
+    this._data = {};
+  }
+}
+
+export class FourKeyMap<TFirst extends string | number, TSecond extends string | number, TThird extends string | number, TFourth extends string | number, TValue> {
+  private _data: TwoKeyMap<TFirst, TSecond, TwoKeyMap<TThird, TFourth, TValue>> = new TwoKeyMap();
+
+  public set(first: TFirst, second: TSecond, third: TThird, fourth: TFourth, value: TValue): void {
+    if (!this._data.get(first, second)) {
+      this._data.set(first, second, new TwoKeyMap());
+    }
+    this._data.get(first, second)!.set(third, fourth, value);
+  }
+
+  public get(first: TFirst, second: TSecond, third: TThird, fourth: TFourth): TValue | undefined {
+    return this._data.get(first, second)?.get(third, fourth);
+  }
+
+  public clear(): void {
+    this._data.clear();
+  }
+}