From eb200afe182327cf316e9ac75294f286eaacf1da Mon Sep 17 00:00:00 2001
From: Krille Fear <christian-pauly@posteo.de>
Date: Thu, 4 Nov 2021 12:20:30 +0100
Subject: [PATCH] refactor: download method should not return null

If the decryption fails, it should
throw an exception and not
return null.
---
 lib/src/event.dart   |  7 +++++--
 test/event_test.dart | 16 ++++++++--------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/lib/src/event.dart b/lib/src/event.dart
index 17fb4d18..fc81e213 100644
--- a/lib/src/event.dart
+++ b/lib/src/event.dart
@@ -523,7 +523,7 @@ class Event extends MatrixEvent {
   /// event and returns it as a [MatrixFile]. If this event doesn't
   /// contain an attachment, this throws an error. Set [getThumbnail] to
   /// true to download the thumbnail instead.
-  Future<MatrixFile?> downloadAndDecryptAttachment(
+  Future<MatrixFile> downloadAndDecryptAttachment(
       {bool getThumbnail = false,
       Future<Uint8List> Function(Uri)? downloadCallback}) async {
     if (![EventTypes.Message, EventTypes.Sticker].contains(type)) {
@@ -584,8 +584,11 @@ class Event extends MatrixEvent {
       );
       uint8list = await client.runInBackground<Uint8List?, EncryptedFile>(
           decryptFile, encryptedFile);
+      if (uint8list == null) {
+        throw ('Unable to decrypt file');
+      }
     }
-    return uint8list != null ? MatrixFile(bytes: uint8list, name: body) : null;
+    return MatrixFile(bytes: uint8list, name: body);
   }
 
   /// Returns if this is a known event type.
diff --git a/test/event_test.dart b/test/event_test.dart
index 6be6317b..28d43c0e 100644
--- a/test/event_test.dart
+++ b/test/event_test.dart
@@ -1196,7 +1196,7 @@ void main() {
       }, room);
       var buffer = await event.downloadAndDecryptAttachment(
           downloadCallback: downloadCallback);
-      expect(buffer?.bytes, FILE_BUFF);
+      expect(buffer.bytes, FILE_BUFF);
       expect(event.attachmentOrThumbnailMxcUrl().toString(),
           'mxc://example.org/file');
       expect(event.attachmentOrThumbnailMxcUrl(getThumbnail: true).toString(),
@@ -1251,11 +1251,11 @@ void main() {
 
       buffer = await event.downloadAndDecryptAttachment(
           downloadCallback: downloadCallback);
-      expect(buffer?.bytes, FILE_BUFF);
+      expect(buffer.bytes, FILE_BUFF);
 
       buffer = await event.downloadAndDecryptAttachment(
           getThumbnail: true, downloadCallback: downloadCallback);
-      expect(buffer?.bytes, THUMBNAIL_BUFF);
+      expect(buffer.bytes, THUMBNAIL_BUFF);
     });
     test('encrypted attachments', () async {
       if (!olmEnabled) return;
@@ -1298,7 +1298,7 @@ void main() {
       }, room);
       var buffer = await event.downloadAndDecryptAttachment(
           downloadCallback: downloadCallback);
-      expect(buffer?.bytes, FILE_BUFF_DEC);
+      expect(buffer.bytes, FILE_BUFF_DEC);
 
       event = Event.fromJson({
         'type': EventTypes.Message,
@@ -1351,11 +1351,11 @@ void main() {
       expect(event.thumbnailMxcUrl.toString(), 'mxc://example.com/thumb');
       buffer = await event.downloadAndDecryptAttachment(
           downloadCallback: downloadCallback);
-      expect(buffer?.bytes, FILE_BUFF_DEC);
+      expect(buffer.bytes, FILE_BUFF_DEC);
 
       buffer = await event.downloadAndDecryptAttachment(
           getThumbnail: true, downloadCallback: downloadCallback);
-      expect(buffer?.bytes, THUMB_BUFF_DEC);
+      expect(buffer.bytes, THUMB_BUFF_DEC);
 
       await room.client.dispose(closeDatabase: true);
     });
@@ -1389,11 +1389,11 @@ void main() {
           downloadCallback: downloadCallback);
       expect(await event.isAttachmentInLocalStore(),
           event.room?.client.database?.supportsFileStoring);
-      expect(buffer?.bytes, FILE_BUFF);
+      expect(buffer.bytes, FILE_BUFF);
       expect(serverHits, 1);
       buffer = await event.downloadAndDecryptAttachment(
           downloadCallback: downloadCallback);
-      expect(buffer?.bytes, FILE_BUFF);
+      expect(buffer.bytes, FILE_BUFF);
       expect(
           serverHits, event.room!.client.database!.supportsFileStoring ? 1 : 2);