Persist AudioService if CallViewController is dismissed

...in response to CR, move the AudioService off of the CallViewController

Adopt multiple observer pattern vs. a singular delegate. Doing so
required implementing some machinery to address the ARC (see:
Weak.swift)

// FREEBIE

Signal.xcodeproj/project.pbxproj

@@ -104,6 +104,7 @@
 		45F170AF1E2F0393003FC1F2 /* CallAudioSessionTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170AE1E2F0393003FC1F2 /* CallAudioSessionTest.swift */; };
 		45F170BB1E2FC5D3003FC1F2 /* CallAudioService.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */; };
 		45F170BC1E2FC5D3003FC1F2 /* CallAudioService.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */; };
+		45F170D61E315310003FC1F2 /* Weak.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170D51E315310003FC1F2 /* Weak.swift */; };
 		45F2B1941D9C9F48000D2C69 /* OWSOutgoingMessageCollectionViewCell.m in Sources */ = {isa = PBXBuildFile; fileRef = 45F2B1931D9C9F48000D2C69 /* OWSOutgoingMessageCollectionViewCell.m */; };
 		45F2B1971D9CA207000D2C69 /* OWSIncomingMessageCollectionViewCell.xib in Resources */ = {isa = PBXBuildFile; fileRef = 45F2B1951D9CA207000D2C69 /* OWSIncomingMessageCollectionViewCell.xib */; };
 		45F2B1981D9CA207000D2C69 /* OWSOutgoingMessageCollectionViewCell.xib in Resources */ = {isa = PBXBuildFile; fileRef = 45F2B1961D9CA207000D2C69 /* OWSOutgoingMessageCollectionViewCell.xib */; };
@@ -699,6 +700,7 @@
 		45F170AE1E2F0393003FC1F2 /* CallAudioSessionTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = CallAudioSessionTest.swift; path = test/call/CallAudioSessionTest.swift; sourceTree = "<group>"; };
 		45F170B31E2F0A6A003FC1F2 /* RTCAudioSession.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RTCAudioSession.h; sourceTree = "<group>"; };
 		45F170BA1E2FC5D3003FC1F2 /* CallAudioService.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CallAudioService.swift; sourceTree = "<group>"; };
+		45F170D51E315310003FC1F2 /* Weak.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Weak.swift; sourceTree = "<group>"; };
 		45F2B1921D9C9F48000D2C69 /* OWSOutgoingMessageCollectionViewCell.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = OWSOutgoingMessageCollectionViewCell.h; sourceTree = "<group>"; };
 		45F2B1931D9C9F48000D2C69 /* OWSOutgoingMessageCollectionViewCell.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = OWSOutgoingMessageCollectionViewCell.m; sourceTree = "<group>"; };
 		45F2B1951D9CA207000D2C69 /* OWSIncomingMessageCollectionViewCell.xib */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = file.xib; path = OWSIncomingMessageCollectionViewCell.xib; sourceTree = "<group>"; };
@@ -1948,6 +1950,7 @@
 				45CD81F01DC03A22004C9430 /* OWSLogger.h */,
 				45CD81F11DC03A22004C9430 /* OWSLogger.m */,
 				450DF2041E0D74AC003D14BE /* Platform.swift */,
+				45F170D51E315310003FC1F2 /* Weak.swift */,
 			);
 			path = util;
 			sourceTree = "<group>";
@@ -3220,6 +3223,7 @@
 				BFB074C719A5611000F2947C /* FutureUtil.m in Sources */,
 				45E1F3A51DEF20A100852CF1 /* NoSignalContactsView.swift in Sources */,
 				FCD274E21A5AFD8000202277 /* PrivacySettingsTableViewController.m in Sources */,
+				45F170D61E315310003FC1F2 /* Weak.swift in Sources */,
 				76EB057218170B33006006FC /* RecentCall.m in Sources */,
 				B97CBFA818860EA3008E0DE9 /* CountryCodeViewController.m in Sources */,
 				B6B1013C196D213F007E3930 /* SignalKeyingStorage.m in Sources */,

Signal/src/call/CallAudioService.swift

@@ -4,7 +4,8 @@
 
 import Foundation
 
-@objc class CallAudioService: NSObject {
+@objc class CallAudioService: NSObject, CallObserver {
+
     private let TAG = "[CallAudioService]"
     private var vibrateTimer: Timer?
     private let soundPlayer = JSQSystemSoundPlayer.shared()!
@@ -21,21 +22,41 @@ import Foundation
     // `pulseDuration` is the small pause between the two vibrations in the pair.
     private let pulseDuration = 0.2
 
-    public var isSpeakerphoneEnabled = false {
-        didSet {
-            handleUpdatedSpeakerphone()
-        }
-    }
-
     // MARK: - Initializers
 
     init(handleRinging: Bool) {
         self.handleRinging = handleRinging
     }
 
+    // MARK: - CallObserver
+
+    internal func stateDidChange(call: SignalCall, state: CallState) {
+        DispatchQueue.main.async {
+            self.handleState(state)
+        }
+    }
+
+    internal func muteDidChange(call: SignalCall, isMuted: Bool) {
+        Logger.verbose("\(TAG) in \(#function) is no-op")
+    }
+
+    internal func speakerphoneDidChange(call: SignalCall, isEnabled: Bool) {
+        if isEnabled {
+            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord, options: .defaultToSpeaker)
+        } else {
+            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord)
+        }
+    }
+
+    internal func hasVideoDidChange(call: SignalCall, hasVideo: Bool) {
+        // no-op
+    }
+
     // MARK: - Service action handlers
 
     public func handleState(_ state: CallState) {
+        Logger.verbose("\(TAG) in \(#function) new state: \(state)")
+
         switch state {
         case .idle: handleIdle()
         case .dialing: handleDialing()
@@ -100,14 +121,6 @@ import Foundation
         stopRinging()
     }
 
-    private func handleUpdatedSpeakerphone() {
-        if isSpeakerphoneEnabled {
-            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord, options: .defaultToSpeaker)
-        } else {
-            setAudioSession(category: AVAudioSessionCategoryPlayAndRecord)
-        }
-    }
-
     // MARK: - Ringing
 
     private func startRinging() {
@@ -151,7 +164,7 @@ import Foundation
         }
     }
 
-    // MARK: - AVAudioSession Mgmt
+    // MARK: - AVAudioSession Helpers
 
     private func setAudioSession(category: String, options: AVAudioSessionCategoryOptions) {
         do {

Signal/src/call/CallService.swift

@@ -924,6 +924,7 @@ fileprivate let timeoutSeconds = 60
         peerConnectionClient?.terminate()
 
         peerConnectionClient = nil
+        call?.removeAllObservers()
         call = nil
         thread = nil
         incomingCallPromise = nil

Signal/src/call/SignalCall.swift

@@ -17,10 +17,11 @@ enum CallState: String {
     case remoteBusy // terminal
 }
 
-protocol CallDelegate: class {
+protocol CallObserver: class {
     func stateDidChange(call: SignalCall, state: CallState)
     func hasVideoDidChange(call: SignalCall, hasVideo: Bool)
     func muteDidChange(call: SignalCall, isMuted: Bool)
+    func speakerphoneDidChange(call: SignalCall, isEnabled: Bool)
 }
 
 /**
@@ -30,7 +31,7 @@ protocol CallDelegate: class {
 
     let TAG = "[SignalCall]"
 
-    weak var delegate: CallDelegate?
+    var observers = [Weak<CallObserver>]()
     let remotePhoneNumber: String
 
     // Signal Service identifier for this Call. Used to coordinate the call across remote clients.
@@ -38,12 +39,16 @@ protocol CallDelegate: class {
 
     // Distinguishes between calls locally, e.g. in CallKit
     let localId: UUID
+    
     var hasVideo = false {
         didSet {
             Logger.debug("\(TAG) hasVideo changed: \(oldValue) -> \(hasVideo)")
-            delegate?.hasVideoDidChange(call: self, hasVideo: hasVideo)
+            for observer in observers {
+                observer.value?.hasVideoDidChange(call: self, hasVideo: hasVideo)
+            }
         }
     }
+
     var state: CallState {
         didSet {
             Logger.debug("\(TAG) state changed: \(oldValue) -> \(state)")
@@ -56,20 +61,35 @@ protocol CallDelegate: class {
             } else {
                 connectedDate = nil
             }
-
+            for observer in observers {
-            delegate?.stateDidChange(call: self, state: state)
+                observer.value?.stateDidChange(call: self, state: state)
+            }
         }
     }
+
     var isMuted = false {
         didSet {
             Logger.debug("\(TAG) muted changed: \(oldValue) -> \(isMuted)")
-            delegate?.muteDidChange(call: self, isMuted: isMuted)
+            for observer in observers {
+                observer.value?.muteDidChange(call: self, isMuted: isMuted)
+            }
+        }
+    }
+
+    var isSpeakerphoneEnabled = false {
+        didSet {
+            Logger.debug("\(TAG) isSpeakerphoneEnabled changed: \(oldValue) -> \(isSpeakerphoneEnabled)")
+            for observer in observers {
+                observer.value?.speakerphoneDidChange(call: self, isEnabled: isSpeakerphoneEnabled)
+            }
         }
     }
     var connectedDate: NSDate?
 
     var error: CallError?
 
+    // MARK: Initializers and Factory Methods
+
     init(localId: UUID, signalingId: UInt64, state: CallState, remotePhoneNumber: String) {
         self.localId = localId
         self.signalingId = signalingId
@@ -85,7 +105,27 @@ protocol CallDelegate: class {
         return SignalCall(localId: localId, signalingId: signalingId, state: .answering, remotePhoneNumber: remotePhoneNumber)
     }
 
+    // -
+
+    func addObserverAndSyncState(observer: CallObserver) {
+        observers.append(Weak(value: observer))
+
+        // Synchronize observer with current call state
+        observer.stateDidChange(call: self, state: self.state)
+    }
+
+    func removeObserver(_ observer: CallObserver) {
+        while let index = observers.index(where: { $0.value === observer }) {
+            observers.remove(at: index)
+        }
+    }
+
+    func removeAllObservers() {
+        observers = []
+    }
+
     // MARK: Equatable
+
     static func == (lhs: SignalCall, rhs: SignalCall) -> Bool {
         return lhs.localId == rhs.localId
     }

Signal/src/call/UserInterface/CallUIAdapter.swift

@@ -42,6 +42,7 @@ class CallUIAdapter {
     let TAG = "[CallUIAdapter]"
     private let adaptee: CallUIAdaptee
     private let contactsManager: OWSContactsManager
+    private let audioService: CallAudioService
 
     required init(callService: CallService, contactsManager: OWSContactsManager, notificationsAdapter: CallNotificationsAdapter) {
         self.contactsManager = contactsManager
@@ -58,9 +59,13 @@ class CallUIAdapter {
             Logger.info("\(TAG) choosing non-callkit adaptee for older iOS")
             adaptee = NonCallKitCallUIAdaptee(callService: callService, notificationsAdapter: notificationsAdapter)
         }
+
+        audioService = CallAudioService(handleRinging: adaptee.hasManualRinger)
     }
 
     internal func reportIncomingCall(_ call: SignalCall, thread: TSContactThread) {
+        call.addObserverAndSyncState(observer: audioService)
+
         let callerName = self.contactsManager.displayName(forPhoneIdentifier: call.remotePhoneNumber)
         adaptee.reportIncomingCall(call, callerName: callerName)
     }
@@ -72,6 +77,8 @@ class CallUIAdapter {
 
     internal func startOutgoingCall(handle: String) -> SignalCall {
         let call = SignalCall.outgoingCall(localId: UUID(), remotePhoneNumber: handle)
+        call.addObserverAndSyncState(observer: audioService)
+
         adaptee.startOutgoingCall(call)
         return call
     }
@@ -97,6 +104,7 @@ class CallUIAdapter {
     }
 
     internal func setIsMuted(call: SignalCall, isMuted: Bool) {
+        // With CallKit, muting is handled by a CXAction, so it must go through the adaptee
         adaptee.setIsMuted(call: call, isMuted: isMuted)
     }
 
@@ -104,6 +112,13 @@ class CallUIAdapter {
         adaptee.setHasVideo(call: call, hasVideo: hasVideo)
     }
 
+    internal func toggleSpeakerphone(call: SignalCall, isEnabled: Bool) {
+        // Speakerphone is not handled by CallKit (e.g. there is no CXAction), so we handle it w/o going through the 
+        // adaptee, relying on the AudioService CallObserver to put the system in a state consistent with the call's 
+        // assigned property.
+        call.isSpeakerphoneEnabled = isEnabled
+    }
+
     // CallKit handles ringing state on it's own. But for non-call kit we trigger ringing start/stop manually.
     internal var hasManualRinger: Bool {
         return adaptee.hasManualRinger

Signal/src/util/Weak.swift

@@ -0,0 +1,29 @@
+//
+//  Copyright © 2017 Open Whisper Systems. All rights reserved.
+//
+
+/**
+ * Container for a weakly referenced object.
+ *
+ * Only use this for |T| with reference-semantic entities
+ * e.g. inheriting from AnyObject or Class-only protocols, but not structs or enums.
+ *
+ *
+ * Based on https://devforums.apple.com/message/981472#981472, but also supports class-only protocols
+ */
+struct Weak<T> {
+    private weak var _value: AnyObject?
+
+    var value: T? {
+        get {
+            return _value as? T
+        }
+        set {
+            _value = newValue as AnyObject
+        }
+    }
+
+    init(value: T) {
+        self.value = value
+    }
+}

Signal/src/view controllers/CallViewController.swift

@@ -10,7 +10,7 @@ import PromiseKit
 // TODO: Add logic to button handlers.
 // TODO: Ensure buttons enabled & disabled as necessary.
 @objc(OWSCallViewController)
-class CallViewController: UIViewController, CallDelegate {
+class CallViewController: UIViewController, CallObserver {
 
     enum CallDirection {
         case unspecified, outgoing, incoming
@@ -22,7 +22,6 @@ class CallViewController: UIViewController, CallDelegate {
 
     let callUIAdapter: CallUIAdapter
     let contactsManager: OWSContactsManager
-    let audioService: CallAudioService
 
     // MARK: Properties
 
@@ -81,7 +80,6 @@ class CallViewController: UIViewController, CallDelegate {
         contactsManager = Environment.getCurrent().contactsManager
         let callService = Environment.getCurrent().callService!
         callUIAdapter = callService.callUIAdapter
-        audioService = CallAudioService(handleRinging: callUIAdapter.hasManualRinger)
         super.init(coder: aDecoder)
     }
 
@@ -89,7 +87,6 @@ class CallViewController: UIViewController, CallDelegate {
         contactsManager = Environment.getCurrent().contactsManager
         let callService = Environment.getCurrent().callService!
         callUIAdapter = callService.callUIAdapter
-        audioService = CallAudioService(handleRinging: callUIAdapter.hasManualRinger)
         super.init(nibName: nil, bundle: nil)
     }
 
@@ -133,8 +130,8 @@ class CallViewController: UIViewController, CallDelegate {
             // No-op, since call service is already set up at this point, the result of which was presenting this viewController.
         }
 
-        call.delegate = self
+        // Subscribe for future call updates
-        stateDidChange(call: call, state: call.state)
+        call.addObserverAndSyncState(observer: self)
     }
 
     func createViews() {
@@ -488,7 +485,11 @@ class CallViewController: UIViewController, CallDelegate {
     func didPressSpeakerphone(sender speakerphoneButton: UIButton) {
         Logger.info("\(TAG) called \(#function)")
         speakerphoneButton.isSelected = !speakerphoneButton.isSelected
-        audioService.isSpeakerphoneEnabled = speakerphoneButton.isSelected
+        if let call = self.call {
+            callUIAdapter.toggleSpeakerphone(call: call, isEnabled: speakerphoneButton.isSelected)
+        } else {
+            Logger.warn("\(TAG) pressed mute, but call was unexpectedly nil")
+        }
     }
 
     func didPressTextMessage(sender speakerphoneButton: UIButton) {
@@ -537,14 +538,13 @@ class CallViewController: UIViewController, CallDelegate {
         self.dismiss(animated: true)
     }
 
-    // MARK: - CallDelegate
+    // MARK: - CallObserver
 
     internal func stateDidChange(call: SignalCall, state: CallState) {
         DispatchQueue.main.async {
             Logger.info("\(self.TAG) new call status: \(state)")
             self.updateCallUI(callState: state)
         }
-        self.audioService.handleState(state)
     }
 
     internal func hasVideoDidChange(call: SignalCall, hasVideo: Bool) {
@@ -558,4 +558,10 @@ class CallViewController: UIViewController, CallDelegate {
             self.updateCallUI(callState: call.state)
         }
     }
+
+    internal func speakerphoneDidChange(call: SignalCall, isEnabled: Bool) {
+        DispatchQueue.main.async {
+            self.updateCallUI(callState: call.state)
+        }
+    }
 }