Fix retain cycle

// FREEBIE

Signal.xcodeproj/project.pbxproj

@@ -105,6 +105,7 @@
 		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 */; };
+		45F170CC1E310E22003FC1F2 /* WeakTimer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 45F170CB1E310E22003FC1F2 /* WeakTimer.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 */; };
@@ -701,6 +702,7 @@
 		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>"; };
+		45F170CB1E310E22003FC1F2 /* WeakTimer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = WeakTimer.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>"; };
@@ -1951,6 +1953,7 @@
 				45CD81F11DC03A22004C9430 /* OWSLogger.m */,
 				450DF2041E0D74AC003D14BE /* Platform.swift */,
 				45F170D51E315310003FC1F2 /* Weak.swift */,
+				45F170CB1E310E22003FC1F2 /* WeakTimer.swift */,
 			);
 			path = util;
 			sourceTree = "<group>";
@@ -3138,6 +3141,7 @@
 				453D28BA1D332DB100D523F0 /* OWSMessagesBubblesSizeCalculator.m in Sources */,
 				45F170AC1E2F0351003FC1F2 /* CallAudioSession.swift in Sources */,
 				B68EF9BB1C0B1EBD009C3DCD /* FLAnimatedImageView.m in Sources */,
+				45F170CC1E310E22003FC1F2 /* WeakTimer.swift in Sources */,
 				A5E9D4BB1A65FAD800E4481C /* TSVideoAttachmentAdapter.m in Sources */,
 				E197B61118BBEC1A00F073E5 /* AudioProcessor.m in Sources */,
 				FCAC964019FEF99A0046DFC5 /* InboxTableViewCell.m in Sources */,

Signal/src/call/CallAudioService.swift

@@ -129,7 +129,10 @@ import Foundation
             return
         }
 
-        vibrateTimer = Timer.scheduledTimer(timeInterval: vibrateRepeatDuration, target: self, selector: #selector(ringVibration), userInfo: nil, repeats: true)
+        vibrateTimer = WeakTimer.scheduledTimer(timeInterval: vibrateRepeatDuration, target: self, userInfo: nil, repeats: true) {[weak self] timer in
+            self?.ringVibration()
+        }
+        vibrateTimer?.fire()
 
         // Stop other sounds and play ringer through external speaker
         setAudioSession(category: AVAudioSessionCategorySoloAmbient)

Signal/src/util/WeakTimer.swift

@@ -0,0 +1,43 @@
+//
+//  Copyright © 2017 Open Whisper Systems. All rights reserved.
+//
+
+/**
+ * As of iOS10, the timer API's take a block, which makes it easy to reference weak self in Swift. This class offers a 
+ * similar API that works pre iOS10.
+ *
+ * Solution modified from
+ * http://stackoverflow.com/questions/16821736/weak-reference-to-nstimer-target-to-prevent-retain-cycle/41003985#41003985
+ */
+final class WeakTimer {
+
+    fileprivate weak var timer: Timer?
+    fileprivate weak var target: AnyObject?
+    fileprivate let action: (Timer) -> Void
+
+    fileprivate init(timeInterval: TimeInterval, target: AnyObject, userInfo: Any?, repeats: Bool, action: @escaping (Timer) -> Void) {
+        self.target = target
+        self.action = action
+        self.timer = Timer.scheduledTimer(timeInterval: timeInterval,
+                                          target: self,
+                                          selector: #selector(fire),
+                                          userInfo: userInfo,
+                                          repeats: repeats)
+    }
+
+    class func scheduledTimer(timeInterval: TimeInterval, target: AnyObject, userInfo: Any?, repeats: Bool, action: @escaping (Timer) -> Void) -> Timer {
+        return WeakTimer(timeInterval: timeInterval,
+                         target: target,
+                         userInfo: userInfo,
+                         repeats: repeats,
+                         action: action).timer!
+    }
+
+    @objc fileprivate func fire(timer: Timer) {
+        if target != nil {
+            action(timer)
+        } else {
+            timer.invalidate()
+        }
+    }
+}