refactor: restore support for QMCv1.

(cherry picked from commit 19239f182d71e2e4362309f08706a91c00bb6bd1)

src/decrypt/qmc.ts

@@ -1,4 +1,4 @@
-import {QmcMask, QmcMaskDetectMflac, QmcMaskDetectMgg, QmcMaskGetDefault} from "./qmcMask";
+import {QmcMask, QmcMaskGetDefault} from "./qmcMask";
 import {toByteArray as Base64Decode} from 'base64-js'
 import {
     AudioMimeType,
@@ -9,7 +9,7 @@ import {
     SniffAudioExt, WriteMetaToFlac, WriteMetaToMp3
 } from "@/decrypt/utils";
 import {parseBlob as metaParseBlob} from "music-metadata-browser";
-import {decryptMGG} from "./qmcv2";
+import {DecryptQMCv2} from "./qmcv2";
 
 
 import iconv from "iconv-lite";
@@ -18,60 +18,49 @@ import {queryAlbumCover, queryKeyInfo, reportKeyUsage} from "@/utils/api";
 
 interface Handler {
     ext: string
-    detect: boolean
+    version: number
-
-    handler(data?: Uint8Array): QmcMask | undefined
 }
 
 export const HandlerMap: { [key: string]: Handler } = {
-    "mgg": {handler: QmcMaskDetectMgg, ext: "ogg", detect: true},
+    "mgg": {ext: "ogg", version: 2},
-    "mflac": {handler: QmcMaskDetectMflac, ext: "flac", detect: true},
+    "mgg1": {ext: "ogg", version: 2},
-    "mgg.cache": {handler: QmcMaskDetectMgg, ext: "ogg", detect: false},
+    "mflac": {ext: "flac", version: 2},
-    "mflac.cache": {handler: QmcMaskDetectMflac, ext: "flac", detect: false},
+    "mflac0": {ext: "flac", version: 2},
-    "qmc0": {handler: QmcMaskGetDefault, ext: "mp3", detect: false},
+
-    "qmc2": {handler: QmcMaskGetDefault, ext: "ogg", detect: false},
+    "qmc0": {ext: "mp3", version: 1},
-    "qmc3": {handler: QmcMaskGetDefault, ext: "mp3", detect: false},
+    "qmc2": {ext: "ogg", version: 1},
-    "qmcogg": {handler: QmcMaskGetDefault, ext: "ogg", detect: false},
+    "qmc3": {ext: "mp3", version: 1},
-    "qmcflac": {handler: QmcMaskGetDefault, ext: "flac", detect: false},
+    "qmcogg": {ext: "ogg", version: 1},
-    "bkcmp3": {handler: QmcMaskGetDefault, ext: "mp3", detect: false},
+    "qmcflac": {ext: "flac", version: 1},
-    "bkcflac": {handler: QmcMaskGetDefault, ext: "flac", detect: false},
+    "bkcmp3": {ext: "mp3", version: 1},
-    "tkm": {handler: QmcMaskGetDefault, ext: "m4a", detect: false},
+    "bkcflac": {ext: "flac", version: 1},
-    "666c6163": {handler: QmcMaskGetDefault, ext: "flac", detect: false},
+    "tkm": {ext: "m4a", version: 1},
-    "6d7033": {handler: QmcMaskGetDefault, ext: "mp3", detect: false},
+    "666c6163": {ext: "flac", version: 1},
-    "6f6767": {handler: QmcMaskGetDefault, ext: "ogg", detect: false},
+    "6d7033": {ext: "mp3", version: 1},
-    "6d3461": {handler: QmcMaskGetDefault, ext: "m4a", detect: false},
+    "6f6767": {ext: "ogg", version: 1},
-    "776176": {handler: QmcMaskGetDefault, ext: "wav", detect: false}
+    "6d3461": {ext: "m4a", version: 1},
+    "776176": {ext: "wav", version: 1}
 };
 
-function mergeUint8(array: Uint8Array[]): Uint8Array {
-    // Get the total length of all arrays.
-    let length = 0;
-    array.forEach(item => {
-      length += item.length;
-    });
-
-    // Create a new array with total length and merge all source arrays.
-    let mergedArray = new Uint8Array(length);
-    let offset = 0;
-    array.forEach(item => {
-      mergedArray.set(item, offset);
-      offset += item.length;
-    });
-
-    return mergedArray;
-}
-
 export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string): Promise<DecryptResult> {
     if (!(raw_ext in HandlerMap)) throw `Qmc cannot handle type: ${raw_ext}`;
     const handler = HandlerMap[raw_ext];
 
-    const decodedParts = await decryptMGG(await file.arrayBuffer());
+    const fileBuffer = await GetArrayBuffer(file);
-    let musicDecoded = mergeUint8(decodedParts);
+    let musicDecoded: Uint8Array;
+    if (handler.version === 1) {
+        const seed = QmcMaskGetDefault();
+        musicDecoded = seed.Decrypt(new Uint8Array(fileBuffer));
+    } else if (handler.version === 2) {
+        musicDecoded = await DecryptQMCv2(fileBuffer);
+    } else {
+        throw new Error(`不支持的加密版本: ${handler.version} (${raw_ext})`);
+    }
 
     const ext = SniffAudioExt(musicDecoded, handler.ext);
     const mime = AudioMimeType[ext];
 
-    let musicBlob = new Blob(decodedParts, {type: mime});
+    let musicBlob = new Blob([musicDecoded], {type: mime});
 
     const musicMeta = await metaParseBlob(musicBlob);
     for (let metaIdx in musicMeta.native) {

src/decrypt/qmcv2.ts

@@ -1,21 +1,36 @@
 import QMCCryptoModule from '@jixun/qmc2-crypto/QMC2-wasm-bundle';
 
-// EOF Magic detection.
+// 检测文件末端使用的缓冲区大小
 const DETECTION_SIZE = 40;
 
-// Process in 2m buffer size
+// 每次处理 2M 的数据
 const DECRYPTION_BUF_SIZE = 2 * 1024 * 1024;
 
+function MergeUint8Array(array: Uint8Array[]): Uint8Array {
+  let length = 0;
+  array.forEach(item => {
+    length += item.length;
+  });
+
+  let mergedArray = new Uint8Array(length);
+  let offset = 0;
+  array.forEach(item => {
+    mergedArray.set(item, offset);
+    offset += item.length;
+  });
+
+  return mergedArray;
+}
+
 /**
  * 解密一个 QMC2 加密的文件。
  *
- * 如果检测并解密成功，返回解密后的 Uint8Array 数组，按顺序拼接即可得到完整文件。
+ * 如果检测并解密成功，返回解密后的 Uint8Array 数据。
- * 若失败，返回 `null`。
  * @param  {ArrayBuffer} mggBlob 读入的文件 Blob
  * @param  {string}         name 文件名
- * @return {Promise<Uint8Array[]|null>}
+ * @return {Promise<Uint8Array|null>}
  */
-export async function decryptMGG(mggBlob: ArrayBuffer) {
+export async function DecryptQMCv2(mggBlob: ArrayBuffer) {
   // 初始化模组
   const QMCCrypto = await QMCCryptoModule();
 
@@ -44,52 +59,46 @@ export async function decryptMGG(mggBlob: ArrayBuffer) {
   QMCCrypto._free(pDetectionBuf);
   QMCCrypto._free(pDetectionResult);
 
-  if (detectOK) {
+  if (!detectOK) {
-    // 计算解密后文件的大小。
+    throw new Error("解密失败: \n  " + detectionError);
-    // 之前得到的 position 为相对当前检测数据起点的偏移。
-    const decryptedSize = mggBlob.byteLength - DETECTION_SIZE + position;
-    // $prog.max = decryptedSize;
-
-    // 提取嵌入到文件的 EKey
-    const ekey = new Uint8Array(
-      mggBlob.slice(decryptedSize, decryptedSize + len)
-    );
-
-    // 解码 UTF-8 数据到 string
-    const decoder = new TextDecoder();
-    const ekey_b64 = decoder.decode(ekey);
-
-    // 初始化加密与缓冲区
-    const hCrypto = QMCCrypto.createInstWidthEKey(ekey_b64);
-    const buf = QMCCrypto._malloc(DECRYPTION_BUF_SIZE);
-
-    const decryptedParts = [];
-    let offset = 0;
-    let bytesToDecrypt = decryptedSize;
-    while (bytesToDecrypt > 0) {
-      const blockSize = Math.min(bytesToDecrypt, DECRYPTION_BUF_SIZE);
-
-      // 解密一些片段
-      const blockData = new Uint8Array(
-        mggBlob.slice(offset, offset + blockSize)
-      );
-      QMCCrypto.writeArrayToMemory(blockData, buf);
-      QMCCrypto.decryptStream(hCrypto, buf, offset, blockSize);
-      decryptedParts.push(QMCCrypto.HEAPU8.slice(buf, buf + blockSize));
-
-      offset += blockSize;
-      bytesToDecrypt -= blockSize;
-      // $prog.value = offset;
-
-      // 避免网页卡死，让 event loop 处理一下其它事件。
-      // Worker 应该不需要等待也可以？
-      // await new Promise((resolve) => setTimeout(resolve));
-    }
-    QMCCrypto._free(buf);
-    hCrypto.delete();
-
-    return decryptedParts;
-  } else {
-    throw new Error("ERROR: could not decrypt\n       " + detectionError);
   }
+
+  // 计算解密后文件的大小。
+  // 之前得到的 position 为相对当前检测数据起点的偏移。
+  const decryptedSize = mggBlob.byteLength - DETECTION_SIZE + position;
+
+  // 提取嵌入到文件的 EKey
+  const ekey = new Uint8Array(
+    mggBlob.slice(decryptedSize, decryptedSize + len)
+  );
+
+  // 解码 UTF-8 数据到 string
+  const decoder = new TextDecoder();
+  const ekey_b64 = decoder.decode(ekey);
+
+  // 初始化加密与缓冲区
+  const hCrypto = QMCCrypto.createInstWidthEKey(ekey_b64);
+  const buf = QMCCrypto._malloc(DECRYPTION_BUF_SIZE);
+
+  const decryptedParts = [];
+  let offset = 0;
+  let bytesToDecrypt = decryptedSize;
+  while (bytesToDecrypt > 0) {
+    const blockSize = Math.min(bytesToDecrypt, DECRYPTION_BUF_SIZE);
+
+    // 解密一些片段
+    const blockData = new Uint8Array(
+      mggBlob.slice(offset, offset + blockSize)
+    );
+    QMCCrypto.writeArrayToMemory(blockData, buf);
+    QMCCrypto.decryptStream(hCrypto, buf, offset, blockSize);
+    decryptedParts.push(QMCCrypto.HEAPU8.slice(buf, buf + blockSize));
+
+    offset += blockSize;
+    bytesToDecrypt -= blockSize;
+  }
+  QMCCrypto._free(buf);
+  hCrypto.delete();
+
+  return MergeUint8Array(decryptedParts);
 }