feat: print performance logs to console.

src/decrypt-worker/crypto/CryptoBase.ts

@@ -1,10 +1,10 @@
 export interface CryptoBase {
-  /**
-   * When returning false, a successful decryption should be checked by its decrypted content instead.
-   */
-  hasSignature(): boolean;
-  isSupported(blob: Blob): Promise<boolean>;
-  decrypt(blob: Blob): Promise<Blob>;
+  cryptoName: string;
+  checkByDecryptHeader: boolean;
+  decryptTargetAudio: boolean;
+
+  checkBySignature?: (buffer: ArrayBuffer) => Promise<boolean>;
+  decrypt(buffer: ArrayBuffer, blob: Blob): Promise<Blob | ArrayBuffer>;
 }
 
 export type CryptoFactory = () => CryptoBase;

src/decrypt-worker/crypto/CryptoFactory.ts

@@ -0,0 +1,19 @@
+import { CryptoFactory } from './CryptoBase';
+
+import { QMC1Crypto } from './qmc/qmc_v1';
+import { QMC2Crypto } from './qmc/qmc_v2';
+import { XiamiCrypto } from './xiami/xiami';
+
+export const allCryptoFactories: CryptoFactory[] = [
+  // Xiami (*.xm)
+  () => new XiamiCrypto(),
+
+  // QMCv2 (*.mflac)
+  () => new QMC2Crypto(),
+
+  // Crypto that does not implement "checkBySignature" or need to decrypt the entire file and then check audio type,
+  //   should be moved to the bottom of the list for performance reasons.
+
+  // QMCv1 (*.qmcflac)
+  () => new QMC1Crypto(),
+];

src/decrypt-worker/crypto/qmc/qmc_v1.ts

@@ -3,15 +3,11 @@ import type { CryptoBase } from '../CryptoBase';
 import key from './qmc_v1.key.ts';
 
 export class QMC1Crypto implements CryptoBase {
-  hasSignature(): boolean {
-    return false;
-  }
+  cryptoName = 'QMCv1';
+  checkByDecryptHeader = true;
+  decryptTargetAudio = true;
 
-  async isSupported(): Promise<boolean> {
-    return true;
-  }
-
-  async decrypt(blob: Blob): Promise<Blob> {
+  async decrypt(_buffer: ArrayBuffer, blob: Blob): Promise<Blob> {
     return transformBlob(blob, (p) => p.make.QMCv1(key));
   }
 }

src/decrypt-worker/crypto/qmc/qmc_v2.ts

@@ -3,15 +3,11 @@ import type { CryptoBase } from '../CryptoBase';
 import { SEED, ENC_V2_KEY_1, ENC_V2_KEY_2 } from './qmc_v2.key.ts';
 
 export class QMC2Crypto implements CryptoBase {
-  hasSignature(): boolean {
-    return false;
-  }
+  cryptoName = 'QMCv2';
+  checkByDecryptHeader = false;
+  decryptTargetAudio = true;
 
-  async isSupported(): Promise<boolean> {
-    return true;
-  }
-
-  async decrypt(blob: Blob): Promise<Blob> {
+  async decrypt(_buffer: ArrayBuffer, blob: Blob): Promise<Blob> {
     return transformBlob(blob, (p) => p.make.QMCv2(p.make.QMCv2FooterParser(SEED, ENC_V2_KEY_1, ENC_V2_KEY_2)));
   }
 }

src/decrypt-worker/crypto/xiami/xiami.ts

@@ -11,8 +11,9 @@
 
 import type { CryptoBase } from '../CryptoBase';
 
-const XIAMI_FILE_MAGIC = new Uint8Array('ifmt'.split('').map((x) => x.charCodeAt(0)));
-const XIAMI_EXPECTED_PADDING = new Uint8Array([0xfe, 0xfe, 0xfe, 0xfe]);
+// little endian
+const XIAMI_FILE_MAGIC = 0x746d6669;
+const XIAMI_EXPECTED_PADDING = 0xfefefefe;
 
 const u8Sub = (a: number, b: number) => {
   if (a > b) {
@@ -23,29 +24,25 @@ const u8Sub = (a: number, b: number) => {
 };
 
 export class XiamiCrypto implements CryptoBase {
-  hasSignature(): boolean {
-    return true;
+  cryptoName = 'Xiami';
+  checkByDecryptHeader = false;
+  decryptTargetAudio = true;
+
+  async checkBySignature(buffer: ArrayBuffer): Promise<boolean> {
+    const header = new DataView(buffer);
+
+    return header.getUint32(0x00, true) === XIAMI_FILE_MAGIC && header.getUint32(0x08, true) === XIAMI_EXPECTED_PADDING;
   }
 
-  async isSupported(blob: Blob): Promise<boolean> {
-    const headerBuffer = await blob.slice(0, 0x10).arrayBuffer();
-    const header = new Uint8Array(headerBuffer);
-
-    return (
-      header.slice(0x00, 0x04).every((b, i) => b === XIAMI_FILE_MAGIC[i]) &&
-      header.slice(0x08, 0x0c).every((b, i) => b === XIAMI_EXPECTED_PADDING[i])
-    );
-  }
-
-  async decrypt(blob: Blob): Promise<Blob> {
-    const headerBuffer = await blob.slice(0, 0x10).arrayBuffer();
+  async decrypt(src: ArrayBuffer): Promise<ArrayBuffer> {
+    const headerBuffer = src.slice(0, 0x10);
     const header = new Uint8Array(headerBuffer);
     const key = u8Sub(header[0x0f], 1);
     const plainTextSize = header[0x0c] | (header[0x0d] << 8) | (header[0x0e] << 16);
-    const decrypted = new Uint8Array(await blob.slice(0x10).arrayBuffer());
+    const decrypted = new Uint8Array(src.slice(0x10));
     for (let i = decrypted.byteLength - 1; i >= plainTextSize; i--) {
       decrypted[i] = u8Sub(key, decrypted[i]);
     }
-    return new Blob([decrypted]);
+    return decrypted;
   }
 }

src/decrypt-worker/util/buffer.ts

@@ -0,0 +1,2 @@
+export const toArrayBuffer = async (src: Blob | ArrayBuffer) => (src instanceof Blob ? await src.arrayBuffer() : src);
+export const toBlob = (src: Blob | ArrayBuffer) => (src instanceof Blob ? src : new Blob([src]));

src/decrypt-worker/worker-handler/decrypt.ts

@@ -1,49 +0,0 @@
-import { fetchParakeet } from '@jixun/libparakeet';
-import { CryptoFactory } from '../crypto/CryptoBase';
-
-import { XiamiCrypto } from '../crypto/xiami/xiami';
-import { QMC1Crypto } from '../crypto/qmc/qmc_v1';
-import { QMC2Crypto } from '../crypto/qmc/qmc_v2';
-
-// Use first 4MiB of the file to perform check.
-const TEST_FILE_HEADER_LEN = 1024 * 1024 * 4;
-
-const decryptorFactories: CryptoFactory[] = [
-  // Xiami (*.xm)
-  () => new XiamiCrypto(),
-
-  // QMCv1 (*.qmcflac)
-  () => new QMC1Crypto(),
-
-  // QMCv2 (*.mflac)
-  () => new QMC2Crypto(),
-];
-
-export const workerDecryptHandler = async (blobURI: string) => {
-  const blob = await fetch(blobURI).then((r) => r.blob());
-  const parakeet = await fetchParakeet();
-
-  for (const factory of decryptorFactories) {
-    const decryptor = factory();
-    if (await decryptor.isSupported(blob)) {
-      try {
-        const decryptedBlob = await decryptor.decrypt(blob);
-
-        // Check if we had a successful decryption
-        const header = await decryptedBlob.slice(0, TEST_FILE_HEADER_LEN).arrayBuffer();
-        const audioExt = parakeet.detectAudioExtension(header);
-        if (!decryptor.hasSignature() && audioExt === 'bin') {
-          // skip this decryptor result
-          continue;
-        }
-
-        return { decrypted: URL.createObjectURL(decryptedBlob), ext: audioExt };
-      } catch (error) {
-        console.error('decrypt failed: ', error);
-        continue;
-      }
-    }
-  }
-
-  throw new Error('could not decrypt file: no working decryptor found');
-};

src/decrypt-worker/worker.ts

@@ -3,7 +3,7 @@ import { DECRYPTION_WORKER_ACTION_NAME } from './constants';
 
 import { getSDKVersion } from '@jixun/libparakeet';
 
-import { workerDecryptHandler } from './worker-handler/decrypt';
+import { workerDecryptHandler } from './worker/handler/decrypt';
 
 const bus = new WorkerServerBus();
 onmessage = bus.onmessage;

src/decrypt-worker/worker/handler/decrypt.ts

@@ -0,0 +1,93 @@
+import { Parakeet, fetchParakeet } from '@jixun/libparakeet';
+import { timedLogger } from '~/util/timedLogger';
+import { allCryptoFactories } from '../../crypto/CryptoFactory';
+import { toArrayBuffer, toBlob } from '~/decrypt-worker/util/buffer';
+import { CryptoBase, CryptoFactory } from '~/decrypt-worker/crypto/CryptoBase';
+
+// Use first 4MiB of the file to perform check.
+const TEST_FILE_HEADER_LEN = 4 * 1024 * 1024;
+
+class DecryptCommandHandler {
+  private label: string;
+
+  constructor(label: string, private parakeet: Parakeet, private blob: Blob, private buffer: ArrayBuffer) {
+    this.label = `DecryptCommandHandler( ${label} )`;
+  }
+
+  log<R>(label: string, fn: () => R): R {
+    return timedLogger(`${this.label}: ${label}`, fn);
+  }
+
+  async decrypt(factories: CryptoFactory[]) {
+    for (const factory of factories) {
+      const decryptor = factory();
+
+      try {
+        const result = await this.decryptFile(decryptor);
+        if (result === null) {
+          continue;
+        }
+        return result;
+      } catch (error) {
+        console.error('decrypt failed: ', error);
+        continue;
+      }
+    }
+
+    throw new Error('could not decrypt file: no working decryptor found');
+  }
+
+  async decryptFile(crypto: CryptoBase) {
+    if (crypto.checkBySignature && !(await crypto.checkBySignature(this.buffer))) {
+      return null;
+    }
+
+    if (crypto.checkByDecryptHeader && !(await this.acceptByDecryptFileHeader(crypto))) {
+      return null;
+    }
+
+    const decrypted = await this.log('decrypt', async () => crypto.decrypt(this.buffer, this.blob));
+
+    // Check if we had a successful decryption
+    const audioExt = await this.log(`detect-audio-ext`, async () => {
+      const header = await toArrayBuffer(decrypted.slice(0, TEST_FILE_HEADER_LEN));
+      return this.parakeet.detectAudioExtension(header);
+    });
+
+    return { decrypted: URL.createObjectURL(toBlob(decrypted)), ext: audioExt };
+  }
+
+  async acceptByDecryptFileHeader(crypto: CryptoBase): Promise<boolean> {
+    // File too small, ignore.
+    if (this.buffer.byteLength <= TEST_FILE_HEADER_LEN) {
+      return true;
+    }
+
+    // Check by decrypt max first 8MiB
+    const decryptedBuffer = await this.log(`${crypto.cryptoName}/decrypt-header-test`, async () =>
+      toArrayBuffer(
+        await crypto.decrypt(this.buffer.slice(0, TEST_FILE_HEADER_LEN), this.blob.slice(0, TEST_FILE_HEADER_LEN))
+      )
+    );
+
+    return this.parakeet.detectAudioExtension(decryptedBuffer) !== 'bin';
+  }
+}
+
+export const workerDecryptHandler = async ({ id, blobURI }: { id: string; blobURI: string }) => {
+  const label = `decrypt( ${id} )`;
+  console.group(label);
+
+  try {
+    return await timedLogger(`${label}/total`, async () => {
+      const parakeet = await timedLogger(`${label}/init`, fetchParakeet);
+      const blob = await timedLogger(`${label}/fetch-src`, async () => fetch(blobURI).then((r) => r.blob()));
+      const buffer = await timedLogger(`${label}/read-src`, async () => blob.arrayBuffer());
+
+      const handler = new DecryptCommandHandler(id, parakeet, blob, buffer);
+      return handler.decrypt(allCryptoFactories);
+    });
+  } finally {
+    (console.groupEnd as (label: string) => void)(label);
+  }
+};

src/util/DecryptionQueue.ts

@@ -8,6 +8,6 @@ export class DecryptionQueue extends ConcurrentQueue<{ id: string; blobURI: stri
   }
 
   async handler(item: { id: string; blobURI: string }): Promise<DecryptionResult> {
-    return this.workerClientBus.request(DECRYPTION_WORKER_ACTION_NAME.DECRYPT, item.blobURI);
+    return this.workerClientBus.request(DECRYPTION_WORKER_ACTION_NAME.DECRYPT, item);
   }
 }

src/util/__tests__/DecryptionQueue.test.ts

@@ -24,6 +24,9 @@ test('should be able to forward request to worker client bus', async () => {
   const queue = new DecryptionQueue(bus, 1);
   await expect(queue.add({ id: 'file://1', blobURI: 'blob://mock-file' })).resolves.toEqual({
     actionName: DECRYPTION_WORKER_ACTION_NAME.DECRYPT,
-    payload: 'blob://mock-file',
+    payload: {
+      blobURI: 'blob://mock-file',
+      id: 'file://1',
+    },
   });
 });

src/util/timedLogger.ts

@@ -0,0 +1,22 @@
+function isPromise<T = unknown>(p: unknown): p is Promise<T> {
+  return !!p && typeof p === 'object' && 'then' in p && 'catch' in p && 'finally' in p;
+}
+
+export function timedLogger<R = unknown>(label: string, fn: () => R): R {
+  console.time(label);
+
+  try {
+    const result = fn();
+
+    if (isPromise(result)) {
+      result.finally(() => {
+        console.timeEnd(label);
+      });
+    }
+
+    return result;
+  } catch (e) {
+    console.timeEnd(label);
+    throw e;
+  }
+}