Fix crash after dismissing a phone call

bridge/src/fmod_darwin.m

@@ -5,15 +5,62 @@
 
 #import <AVFoundation/AVFoundation.h>
 
+#define AUDIO_RESUME_RETRY_COUNT 20
+#define AUDIO_RESUME_RETRY_INTERVAL 0.2
+
+static NSTimer * resumeTimer = nil;
+
+// In case it doesn't work from the first try, retry activating the audio session
+// a few times. For example, after dismissing a phone call, [AVAudioSession setActive: error:]
+// errors out from the first try, but works on the second
+static void resumeAudioSession(int retries) {
+    @autoreleasepool {
+        NSError * error;
+        BOOL success = [[AVAudioSession sharedInstance] setActive:TRUE error: &error];
+        if (success) {
+            FMODBridge_resumeMixer();
+            return;
+        }
+
+        if (error) {
+            LOGW("Cannot activate audio session: %s", [[error localizedDescription] UTF8String]);
+        } else {
+            LOGW("Cannot activate audio session and no error was issued");
+        }
+
+        if (retries <= 0) {
+            LOGE("Cannot activate audio session. Not retrying anymore.");
+            return;
+        }
+
+        resumeTimer = [NSTimer
+            scheduledTimerWithTimeInterval: AUDIO_RESUME_RETRY_INTERVAL
+            repeats: NO
+            block: ^(NSTimer *timer) {
+                resumeTimer = nil;
+                resumeAudioSession(retries - 1);
+            }
+        ];
+    }
+}
+
 void FMODBridge_initIOSInterruptionHandler() {
     @autoreleasepool {
         [[NSNotificationCenter defaultCenter] addObserverForName:AVAudioSessionInterruptionNotification object:nil queue:nil usingBlock:^(NSNotification *notification) {
-            if ([[notification.userInfo valueForKey:AVAudioSessionInterruptionTypeKey] intValue] == AVAudioSessionInterruptionTypeBegan) {
+            NSUInteger typeValue = [[notification.userInfo valueForKey:AVAudioSessionInterruptionTypeKey] intValue];
+
+            if (typeValue == AVAudioSessionInterruptionTypeBegan) {
+                if (resumeTimer) {
+                    [resumeTimer invalidate];
+                    resumeTimer = nil;
+                }
                 FMODBridge_suspendMixer();
-            } else {
-                BOOL success = [[AVAudioSession sharedInstance] setActive:TRUE error:nil];
-                assert(success);
-                FMODBridge_resumeMixer();
+
+            } else if (typeValue == AVAudioSessionInterruptionTypeEnded) {
+                NSUInteger optionsValue = [[notification.userInfo valueForKey:AVAudioSessionInterruptionOptionKey] intValue];
+                if (optionsValue & AVAudioSessionInterruptionOptionShouldResume) {
+                    resumeAudioSession(AUDIO_RESUME_RETRY_COUNT);
+                }
             }
         }];
     }