Refactor of asset bundles

plugos/asset_bundle/bundle.ts

@@ -0,0 +1,69 @@
+import { base64Decode, base64Encode } from "./base64.ts";
+import { mime } from "../deps.ts";
+
+export type AssetJson = Record<string, string>;
+
+export class AssetBundle {
+  readonly bundle: AssetJson;
+
+  constructor(bundle: AssetJson = {}) {
+    this.bundle = bundle;
+  }
+
+  has(path: string): boolean {
+    return path in this.bundle;
+  }
+
+  listFiles(): string[] {
+    return Object.keys(this.bundle);
+  }
+
+  readFileSync(
+    path: string,
+  ): Uint8Array {
+    const content = this.bundle[path];
+    if (!content) {
+      throw new Error(`No such file ${path}`);
+    }
+    const data = content.split(",", 2)[1];
+    return base64Decode(data);
+  }
+
+  readFileAsDataUrl(path: string): string {
+    const content = this.bundle[path];
+    if (!content) {
+      throw new Error(`No such file ${path}`);
+    }
+    return content;
+  }
+
+  readTextFileSync(
+    path: string,
+  ): string {
+    return new TextDecoder().decode(this.readFileSync(path));
+  }
+
+  getMimeType(
+    path: string,
+  ): string {
+    const content = this.bundle[path];
+    if (!content) {
+      throw new Error(`No such file ${path}`);
+    }
+    return content.split(";")[0].split(":")[1];
+  }
+
+  writeFileSync(path: string, data: Uint8Array) {
+    const encoded = base64Encode(data);
+    const mimeType = mime.getType(path);
+    this.bundle[path] = `data:${mimeType};base64,${encoded}`;
+  }
+
+  writeTextFileSync(path: string, s: string) {
+    this.writeFileSync(path, new TextEncoder().encode(s));
+  }
+
+  toJSON(): AssetJson {
+    return this.bundle;
+  }
+}