🐛 Fix skipping of encryption header

src/ssn/extractFileStream.ts

@@ -4,12 +4,13 @@ import * as stream from 'stream';
 import * as zlib from 'zlib';
 import { ISsnFileEntry } from '../interfaces/ISsnFileEntry';
 import decryptStream from './streams/decryptStream';
+import waitReadableLength from './streams/waitReadableLength';
 
 /** Extracts the file with the given metadata from the stream.
  * The stream must already start at the .zip's local file header
  * and must transparently span across multiple disks if necessary.
  */
-export default function extractFileStream(file: ISsnFileEntry, inputStream: stream.Readable, skipDecompression: boolean = false): stream.Readable {
+export default async function extractFileStream(file: ISsnFileEntry, inputStream: stream.Readable, skipDecompression: boolean = false): Promise<stream.Readable> {
   let curStream = inputStream;
 
   //pipe into decryption if file is encrypted
@@ -17,7 +18,12 @@ export default function extractFileStream(file: ISsnFileEntry, inputStream: stre
     const decryptTransform = decryptStream(file.decryptionKeys);
     curStream = curStream.pipe(decryptTransform);
     //skip encryption header
-    curStream.read(12);
+    const encryptionHeader = curStream.read(12);
+    if (encryptionHeader === null) {
+      //need to wait until data is ready for reading
+      await waitReadableLength(curStream, 30);
+      curStream.read(30);
+    }
   }
 
   if (!skipDecompression) {

src/ssn/getManifest.ts

@@ -37,7 +37,7 @@ export default async function getManifest(product: Product): Promise<IManifest>
 
   //Extract manifest.xml file
   await readLocalFileHeader(stream, true);
-  const patchmanifestStream = extractFileStream(firstFile, stream);
+  const patchmanifestStream = await extractFileStream(firstFile, stream);
 
   //Convert ArrayBuffer to string
   const patchmanifestXml = await streamToString(patchmanifestStream);

src/ssn/getPatch.ts

@@ -40,7 +40,7 @@ export default async function getPatch(product: Product, from: number, to: numbe
   fileEntries.filter((file) => file.diffType === SsnDiffType.NewFile).forEach(async (file) => {
     try {
       const fileStream = await getFileFromDisks(diskFilenames, { diskStart: file.diskNumberStart, offset: file.offset, length: file.compressedSize });
-      const fileContents = extractFileStream(file, fileStream, true);
+      const fileContents = await extractFileStream(file, fileStream, true);
       console.debug(file.name, file.compressedSize, await streamToArrayBuffer(fileContents));
       //TODO: need to write to disk
     } catch (error) {
@@ -52,7 +52,7 @@ export default async function getPatch(product: Product, from: number, to: numbe
   fileEntries.filter((file) => file.diffType === SsnDiffType.Changed).forEach(async (file) => {
     try {
       const fileStream = await getFileFromDisks(diskFilenames, { diskStart: file.diskNumberStart, offset: file.offset, length: file.compressedSize });
-      const fileContents = extractFileStream(file, fileStream, true);
+      const fileContents = await extractFileStream(file, fileStream, true);
       console.debug(file.name, file.compressedSize, await streamToArrayBuffer(fileContents));
       //TODO: need to apply diffing, then write to disk
     } catch (error) {

src/ssn/getSolidpkg.ts

@@ -42,7 +42,7 @@ export default async function getSolidpkg(product: Product, from: number, to: nu
 
   //Extract metafile.solid file
   await readLocalFileHeader(stream, true);
-  const solidFileStream = extractFileStream(firstFile, stream);
+  const solidFileStream = await extractFileStream(firstFile, stream);
   const solidFileArrayBuffer = await streamToArrayBuffer(solidFileStream);
   const solidContents = parseBencode(new DataView(solidFileArrayBuffer.buffer)) as ISolid;
 

src/ssn/streams/readLocalFileHeader.ts

@@ -1,16 +1,5 @@
 import * as stream from 'stream';
-
+import waitReadableLength from './waitReadableLength';
-/** Returns a promise that resolves as soon as the given stream has the given number of bytes ready for reading. */
-function waitReadableLength(inputStream: stream.Readable, minLength: number): Promise<void> {
-  return new Promise((resolve) => {
-    const interval = setInterval(() => {
-      if (inputStream.readableLength >= minLength) {
-        clearInterval(interval);
-        resolve();
-      }
-    }, 100);
-  });
-}
 
 /** Reads the local file header, which is included before
  * each stored file, and advances the stream accordingly.

src/ssn/streams/waitReadableLength.ts

@@ -0,0 +1,13 @@
+import * as stream from 'stream';
+
+/** Returns a promise that resolves as soon as the given stream has the given number of bytes ready for reading. */
+export default function waitReadableLength(inputStream: stream.Readable, minLength: number): Promise<void> {
+  return new Promise((resolve) => {
+    const interval = setInterval(() => {
+      if (inputStream.readableLength >= minLength) {
+        clearInterval(interval);
+        resolve();
+      }
+    }, 100);
+  });
+}