Activate audio at the proper time

// FREEBIE

Signal/src/call/CallAudioService.swift

@@ -137,9 +137,8 @@ struct AudioSource: Hashable {
     // `pulseDuration` is the small pause between the two vibrations in the pair.
     private let pulseDuration = 0.2
 
-    static private let sharedAudioSession = CallAudioSession()
     var audioSession: CallAudioSession {
-        return type(of: self).sharedAudioSession
+        return CallAudioSession.shared
     }
 
     // MARK: - Initializers
@@ -249,12 +248,6 @@ struct AudioSource: Hashable {
         } catch {
             owsFail("\(TAG) failed setting audio source with error: \(error) isSpeakerPhoneEnabled: \(call.isSpeakerphoneEnabled)")
         }
-
-        if call.state == .connected, !call.isOnHold {
-            audioSession.isRTCAudioEnabled = true
-        } else {
-            audioSession.isRTCAudioEnabled = false
-        }
     }
 
     // MARK: - Service action handlers

Signal/src/call/CallAudioSession.swift

@@ -17,6 +17,11 @@ import WebRTC
 class CallAudioSession {
 
     let TAG = "[CallAudioSession]"
+
+    // Force singleton access
+    static let shared = CallAudioSession()
+    private init() {}
+
     /**
      * The private class that manages AVAudioSession for WebRTC
      */
@@ -33,7 +38,7 @@ class CallAudioSession {
 
     /**
      * Because we useManualAudio with our RTCAudioSession, we have to start/stop the recording audio session ourselves.
-     * Else, we start recording before the next call is ringing.
+     * See header for details on  manual audio.
      */
     var isRTCAudioEnabled: Bool {
         get {

Signal/src/call/NonCallKitCallUIAdaptee.swift

@@ -81,6 +81,7 @@ class NonCallKitCallUIAdaptee: CallUIAdaptee {
             return
         }
 
+        CallAudioSession.shared.isRTCAudioEnabled = true
         self.callService.handleAnswerCall(call)
     }
 
@@ -113,7 +114,8 @@ class NonCallKitCallUIAdaptee: CallUIAdaptee {
 
     func recipientAcceptedCall(_ call: SignalCall) {
         AssertIsOnMainThread()
-        // no-op
+
+        CallAudioSession.shared.isRTCAudioEnabled = true
     }
 
     func localHangupCall(_ call: SignalCall) {

Signal/src/call/Speakerbox/CallKitCallUIAdaptee.swift

@@ -341,17 +341,14 @@ final class CallKitCallUIAdaptee: NSObject, CallUIAdaptee, CXProviderDelegate {
 
         Logger.debug("\(TAG) Received \(#function)")
 
-        // Audio Session is managed by CallAudioService, which observes changes on the
-        // SignalCall directly.
+        CallAudioSession.shared.isRTCAudioEnabled = true
     }
 
     func provider(_ provider: CXProvider, didDeactivate audioSession: AVAudioSession) {
         AssertIsOnMainThread()
 
         Logger.debug("\(TAG) Received \(#function)")
-
-        // Audio Session is managed by CallAudioService, which observes changes on the
-        // SignalCall directly.
+        CallAudioSession.shared.isRTCAudioEnabled = false
     }
 
     // MARK: - Util