Show alert when user tries to play an invalid audio file.

// FREEBIE

Signal/src/Models/TSMessageAdapaters/TSVideoAttachmentAdapter.m

@@ -340,6 +340,11 @@ NS_ASSUME_NONNULL_BEGIN
     if (self.audioDurationSeconds == 0.f) {
         NSError *error;
         AVAudioPlayer *audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:self.fileURL error:&error];
+        if (error && [error.domain isEqualToString:NSOSStatusErrorDomain]
+            && (error.code == kAudioFileInvalidFileError || error.code == kAudioFileStreamError_InvalidFile)) {
+            // Ignore "invalid audio file" errors.
+            return;
+        }
         OWSAssert(!error);
         if (!error) {
             self.audioDurationSeconds = (CGFloat)[audioPlayer duration];

Signal/src/ViewControllers/OWSAudioAttachmentPlayer.m

@@ -3,6 +3,7 @@
 //
 
 #import "OWSAudioAttachmentPlayer.h"
+#import "Signal-Swift.h"
 #import "TSAttachment.h"
 #import "TSAttachmentStream.h"
 #import "TSVideoAttachmentAdapter.h"
@@ -111,6 +112,14 @@ NS_ASSUME_NONNULL_BEGIN
         if (error) {
             DDLogError(@"%@ error: %@", self.tag, error);
             [self stop];
+
+            if ([error.domain isEqualToString:NSOSStatusErrorDomain]
+                && (error.code == kAudioFileInvalidFileError || error.code == kAudioFileStreamError_InvalidFile)) {
+                [OWSAlerts showAlertWithTitle:NSLocalizedString(@"ALERT_ERROR_TITLE", @"")
+                                      message:NSLocalizedString(@"INVALID_AUDIO_FILE_ALERT_ERROR_MESSAGE",
+                                                  @"Message for the alert indicating that an audio file is invalid.")];
+            }
+
             return;
         }
         self.audioPlayer.delegate = self;

Signal/translations/en.lproj/Localizable.strings

@@ -580,6 +580,9 @@
 /* No comment provided by engineer. */
 "INCOMING_INCOMPLETE_CALL" = "Incomplete incoming call from";
 
+/* Message for the alert indicating that an audio file is invalid. */
+"INVALID_AUDIO_FILE_ALERT_ERROR_MESSAGE" = "Invalid audio file.";
+
 /* Alert body when contacts disabled while trying to invite contacts to signal */
 "INVITE_FLOW_REQUIRES_CONTACT_ACCESS_BODY" = "To invite your contacts, you need to allow Signal access to your contacts in the Settings app.";