🐛 Fix end of file reached error

src/interfaces/ISsnFileEntry.ts

@@ -24,7 +24,7 @@ interface ISsnFileEntry {
   name: string;
   /** Uncompressed size */
   size: number;
-  /** Stored size (size of compressed data + 12 byte encryption header if applicable) */
+  /** Stored size (size of compressed data + 12 byte encryption header if applicable). Does not include the local ZIP file header, which is slightly longer than 30 bytes. */
   compressedSize: number;
   /** Decryption keys needed to decrypt the file */
   decryptionKeys: [number, number, number] | undefined;

src/ssn/extractFileStream.ts

@@ -4,6 +4,7 @@ import * as stream from 'stream';
 import * as zlib from 'zlib';
 import { ISsnFileEntry } from '../interfaces/ISsnFileEntry';
 import decryptStream from './streams/decryptStream';
+import streamSetMaxLength from './streams/streamSetMaxLength';
 
 /** Extracts the file with the given metadata from the stream.
  * The stream must already start at the .zip's local file header
@@ -32,9 +33,11 @@ export default function extractFileStream(file: ISsnFileEntry, inputStream: stre
 
   let curStream = inputStream;
 
+  curStream = streamSetMaxLength(curStream, file.compressedSize);
+
   //pipe into decryption if file is encrypted
   if (file.decryptionKeys !== undefined) {
-    const decryptTransform = decryptStream([...file.decryptionKeys] as [number, number, number]);
+    const decryptTransform = decryptStream(file.decryptionKeys);
     curStream = curStream.pipe(decryptTransform);
   }
 

src/ssn/getManifest.ts

@@ -32,7 +32,7 @@ export default async function getManifest(product: Product): Promise<IManifest>
     throw new Error(`Expected .patchmanifest to contain a file called manifest.xml but it is called "${firstFile.name}".`);
   }
 
-  const stream = arrayBufferToStream(ssnFile, firstFile.offset, firstFile.compressedSize);
+  const stream = arrayBufferToStream(ssnFile, firstFile.offset);
 
   //Extract manifest.xml file
   const patchmanifestStream = extractFileStream(firstFile, stream);

src/ssn/getSolidpkg.ts

@@ -37,7 +37,7 @@ export default async function getSolidpkg(product: Product, from: number, to: nu
     throw new Error(`Expected .solidpkg to contain a file called metafile.solid but it is called "${firstFile.name}".`);
   }
 
-  const stream = arrayBufferToStream(ssnFile, firstFile.offset, firstFile.compressedSize);
+  const stream = arrayBufferToStream(ssnFile, firstFile.offset);
 
   //Extract metafile.solid file
   const solidFileStream = extractFileStream(firstFile, stream);

src/ssn/streams/arrayBufferToStream.ts

@@ -11,7 +11,7 @@ export default function arrayBufferToStream(arrayBuffer: ArrayBuffer, offset: nu
   }
 
   let position = offset;
-  const endPosition = (length !== undefined) ? offset + length : arrayBuffer.byteLength;
+  const endPosition = (length !== undefined) ? (offset + length) : arrayBuffer.byteLength;
   const outStream = new stream.Readable({
     read(size) {
       const chunkSize = Math.min(size || BUFFER_SIZE, endPosition - position); //TODO: we can probably remove BUFFER_SIZE

src/ssn/streams/streamSetMaxLength.ts

@@ -0,0 +1,34 @@
+import * as stream from 'stream';
+
+/** Takes the given ReadableStream and returns a ReadableStream with the same contents but that terminates after the given length. */
+export default function streamSetMaxLength(inputStream: stream.Readable, maxLength: number): stream.Readable {
+  if (maxLength <= 0) {
+    throw new RangeError('maxLength is out of bounds.');
+  }
+
+  let remaining = maxLength;
+
+  const outStream = new stream.Readable({
+    read(size) {
+      //If no size is provided, just pass through all remaining bytes
+      if (size === undefined) {
+        this.push(inputStream.read(remaining));
+        remaining = 0;
+        //End is reached, terminate stream
+        this.push(null);
+      } else {
+        //Otherwise, pass through however many bytes we can
+        const clampedSize = Math.min(size, remaining);
+        this.push(inputStream.read(clampedSize));
+        remaining -= clampedSize;
+
+        //If end is reached, terminate stream
+        if (remaining <= 0) {
+          this.push(null);
+        }
+      }
+    },
+  });
+
+  return outStream;
+}