faet: add support of xmly android (#1)

package.json

@@ -20,7 +20,7 @@
     "@chakra-ui/react": "^2.6.1",
     "@emotion/react": "^11.11.0",
     "@emotion/styled": "^11.11.0",
-    "@jixun/libparakeet": "0.0.0-exp.16",
+    "@jixun/libparakeet": "0.0.0-exp.17",
     "@reduxjs/toolkit": "^1.9.5",
     "framer-motion": "^10.12.8",
     "nanoid": "^4.0.2",

pnpm-lock.yaml

@@ -14,8 +14,8 @@ dependencies:
     specifier: ^11.11.0
     version: 11.11.0(@emotion/react@11.11.0)(@types/react@18.0.28)(react@18.2.0)
   '@jixun/libparakeet':
-    specifier: 0.0.0-exp.16
-    version: 0.0.0-exp.16
+    specifier: 0.0.0-exp.17
+    version: 0.0.0-exp.17
   '@reduxjs/toolkit':
     specifier: ^1.9.5
     version: 1.9.5(react-redux@8.0.5)(react@18.2.0)
@@ -2022,9 +2022,9 @@ packages:
       chalk: 4.1.2
     dev: true
 
-  /@jixun/libparakeet@0.0.0-exp.16:
+  /@jixun/libparakeet@0.0.0-exp.17:
     resolution:
-      { integrity: sha512-jDj9kju0tCJyesV+yi4xcOGClrFgdarkcG/aGP3tRfonf1l8y11A8lVwbp3cWXJcrgHAn7683rTEUYitg9TfpA== }
+      { integrity: sha512-DazwsjE8KDNo3gHDILozgNMQwvQXY2N5CdXKvIMMV4xFOnEBVbJRaG5r7rmGoWnplQZebQAW+otwyVUtO1/ZdQ== }
     dev: false
 
   /@jridgewell/gen-mapping@0.3.3:

src/decrypt-worker/crypto/CryptoBase.ts

@@ -1,7 +1,12 @@
 export interface CryptoBase {
   cryptoName: string;
   checkByDecryptHeader: boolean;
-  decryptTargetAudio: boolean;
+
+  /**
+   * If set, this new extension will be used instead.
+   * Useful for non-audio format, e.g. qrc to lrc/xml.
+   */
+  overrideExtension?: string;
 
   checkBySignature?: (buffer: ArrayBuffer) => Promise<boolean>;
   decrypt(buffer: ArrayBuffer, blob: Blob): Promise<Blob | ArrayBuffer>;

src/decrypt-worker/crypto/CryptoFactory.ts

@@ -3,17 +3,22 @@ import { CryptoFactory } from './CryptoBase';
 import { QMC1Crypto } from './qmc/qmc_v1';
 import { QMC2Crypto } from './qmc/qmc_v2';
 import { XiamiCrypto } from './xiami/xiami';
+import { XimalayaAndroidCrypto } from './xmly/xmly_android';
 
 export const allCryptoFactories: CryptoFactory[] = [
   // Xiami (*.xm)
-  () => new XiamiCrypto(),
+  XiamiCrypto.make,
 
   // QMCv2 (*.mflac)
-  () => new QMC2Crypto(),
+  QMC2Crypto.make,
 
   // 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(),
+  QMC1Crypto.make,
+
+  // Ximalaya (Android)
+  XimalayaAndroidCrypto.makeX2M,
+  XimalayaAndroidCrypto.makeX3M,
 ];

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

@@ -3,11 +3,14 @@ import type { CryptoBase } from '../CryptoBase';
 import key from './qmc_v1.key.ts';
 
 export class QMC1Crypto implements CryptoBase {
-  cryptoName = 'QMCv1';
+  cryptoName = 'QMC/v1';
   checkByDecryptHeader = true;
-  decryptTargetAudio = true;
 
-  async decrypt(_buffer: ArrayBuffer, blob: Blob): Promise<Blob> {
-    return transformBlob(blob, (p) => p.make.QMCv1(key));
+  async decrypt(buffer: ArrayBuffer): Promise<Blob> {
+    return transformBlob(buffer, (p) => p.make.QMCv1(key));
+  }
+
+  public static make() {
+    return new QMC1Crypto();
   }
 }

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

@@ -3,11 +3,14 @@ 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 {
-  cryptoName = 'QMCv2';
+  cryptoName = 'QMC/v2';
   checkByDecryptHeader = false;
-  decryptTargetAudio = true;
 
-  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)));
+  async decrypt(buffer: ArrayBuffer): Promise<Blob> {
+    return transformBlob(buffer, (p) => p.make.QMCv2(p.make.QMCv2FooterParser(SEED, ENC_V2_KEY_1, ENC_V2_KEY_2)));
+  }
+
+  public static make() {
+    return new QMC2Crypto();
   }
 }

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

@@ -26,7 +26,6 @@ const u8Sub = (a: number, b: number) => {
 export class XiamiCrypto implements CryptoBase {
   cryptoName = 'Xiami';
   checkByDecryptHeader = false;
-  decryptTargetAudio = true;
 
   async checkBySignature(buffer: ArrayBuffer): Promise<boolean> {
     const header = new DataView(buffer);
@@ -45,4 +44,8 @@ export class XiamiCrypto implements CryptoBase {
     }
     return decrypted;
   }
+
+  public static make() {
+    return new XiamiCrypto();
+  }
 }

src/decrypt-worker/crypto/xmly/xmly_android.key.ts

@@ -0,0 +1,17 @@
+export interface XimalayaAndroidKey {
+  contentKey: string;
+  init: number;
+  step: number;
+}
+
+export const XimalayaX2MKey: XimalayaAndroidKey = {
+  contentKey: 'xmly',
+  init: 0.615243,
+  step: 3.837465,
+};
+
+export const XimalayaX3MKey: XimalayaAndroidKey = {
+  contentKey: '3989d111aad5613940f4fc44b639b292',
+  init: 0.726354,
+  step: 3.948576,
+};

src/decrypt-worker/crypto/xmly/xmly_android.ts

@@ -0,0 +1,29 @@
+import { transformBlob } from '~/decrypt-worker/util/transformBlob';
+import type { CryptoBase } from '../CryptoBase.js';
+import { XimalayaAndroidKey, XimalayaX2MKey, XimalayaX3MKey } from './xmly_android.key.js';
+
+export class XimalayaAndroidCrypto implements CryptoBase {
+  cryptoName = 'Ximalaya/Android';
+  checkByDecryptHeader = true;
+  constructor(private key: XimalayaAndroidKey) {}
+
+  async decrypt(buffer: ArrayBuffer): Promise<Blob> {
+    const { contentKey, init, step } = this.key;
+    return transformBlob(buffer, (p) => {
+      const transformer = p.make.XimalayaAndroid(init, step, contentKey);
+      if (!transformer) {
+        throw new Error('could not make xmly transformer, is key invalid?');
+      }
+
+      return transformer;
+    });
+  }
+
+  public static makeX2M() {
+    return new XimalayaAndroidCrypto(XimalayaX2MKey);
+  }
+
+  public static makeX3M() {
+    return new XimalayaAndroidCrypto(XimalayaX3MKey);
+  }
+}

src/decrypt-worker/util/transformBlob.ts

@@ -1,7 +1,8 @@
 import { Transformer, Parakeet, TransformResult, fetchParakeet } from '@jixun/libparakeet';
+import { toArrayBuffer } from './buffer';
 
 export async function transformBlob(
-  blob: Blob,
+  blob: Blob | ArrayBuffer,
   transformerFactory: (p: Parakeet) => Transformer | Promise<Transformer>,
   parakeet?: Parakeet
 ) {
@@ -12,7 +13,7 @@ export async function transformBlob(
     const transformer = await transformerFactory(mod);
     cleanup.push(() => transformer.delete());
 
-    const reader = mod.make.Reader(await blob.arrayBuffer());
+    const reader = mod.make.Reader(await toArrayBuffer(blob));
     cleanup.push(() => reader.delete());
 
     const sink = mod.make.WriterSink();
@@ -21,7 +22,7 @@ export async function transformBlob(
 
     const result = transformer.Transform(writer, reader);
     if (result !== TransformResult.OK) {
-      throw new Error(`transform failed with error: ${TransformResult[result]} (${result})`);
+      throw new Error(`transformer<${transformer.Name}> failed with error: ${TransformResult[result]} (${result})`);
     }
 
     return sink.collectBlob();

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

@@ -46,17 +46,24 @@ class DecryptCommandHandler {
       return null;
     }
 
-    const decrypted = await this.log('decrypt', async () => crypto.decrypt(this.buffer, this.blob));
+    const decrypted = await this.log(`decrypt (${crypto.cryptoName})`, () => 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);
-    });
+    const audioExt = crypto.overrideExtension ?? (await this.detectAudioExtension(decrypted));
+    if (crypto.checkByDecryptHeader && audioExt === 'bin') {
+      return null;
+    }
 
     return { decrypted: URL.createObjectURL(toBlob(decrypted)), ext: audioExt };
   }
 
+  async detectAudioExtension(data: Blob | ArrayBuffer): Promise<string> {
+    return this.log(`detect-audio-ext`, async () => {
+      const header = await toArrayBuffer(data.slice(0, TEST_FILE_HEADER_LEN));
+      return this.parakeet.detectAudioExtension(header);
+    });
+  }
+
   async acceptByDecryptFileHeader(crypto: CryptoBase): Promise<boolean> {
     // File too small, ignore.
     if (this.buffer.byteLength <= TEST_FILE_HEADER_LEN) {