UI: use NotificationToken to properly clean up observers

When the variable goes out of scope, the observer isn't removed unless
an explicit call is made to the token.

Signed-off-by: Andrej Mihajlov <and@mullvad.net>

4 files changed, 67 insertions, 25 deletions

diff --git a/Sources/Shared/NotificationToken.swift b/Sources/Shared/NotificationToken.swift
new file mode 100644
index 0000000..df5bc25
--- /dev/null
+++ b/Sources/Shared/NotificationToken.swift
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: MIT
+// Copyright © 2018-2020 WireGuard LLC. All Rights Reserved.
+
+import Foundation
+
+/// This source file contains bits of code from:
+/// https://oleb.net/blog/2018/01/notificationcenter-removeobserver/
+
+/// Wraps the observer token received from
+/// `NotificationCenter.addObserver(forName:object:queue:using:)`
+/// and unregisters it in deinit.
+final class NotificationToken {
+    let notificationCenter: NotificationCenter
+    let token: Any
+
+    init(notificationCenter: NotificationCenter = .default, token: Any) {
+        self.notificationCenter = notificationCenter
+        self.token = token
+    }
+
+    deinit {
+        notificationCenter.removeObserver(token)
+    }
+}
+
+extension NotificationCenter {
+    /// Convenience wrapper for addObserver(forName:object:queue:using:)
+    /// that returns our custom `NotificationToken`.
+    func observe(name: NSNotification.Name?, object obj: Any?, queue: OperationQueue?, using block: @escaping (Notification) -> Void) -> NotificationToken {
+        let token = addObserver(forName: name, object: obj, queue: queue, using: block)
+        return NotificationToken(notificationCenter: self, token: token)
+    }
+}
diff --git a/Sources/WireGuardApp/Tunnel/TunnelsManager.swift b/Sources/WireGuardApp/Tunnel/TunnelsManager.swift
index 024c3fd..93aa384 100644
--- a/Sources/WireGuardApp/Tunnel/TunnelsManager.swift
+++ b/Sources/WireGuardApp/Tunnel/TunnelsManager.swift
@@ -23,9 +23,9 @@ class TunnelsManager {
     private var tunnels: [TunnelContainer]
     weak var tunnelsListDelegate: TunnelsManagerListDelegate?
     weak var activationDelegate: TunnelsManagerActivationDelegate?
-    private var statusObservationToken: AnyObject?
-    private var waiteeObservationToken: AnyObject?
-    private var configurationsObservationToken: AnyObject?
+    private var statusObservationToken: NotificationToken?
+    private var waiteeObservationToken: NSKeyValueObservation?
+    private var configurationsObservationToken: NotificationToken?
 
     init(tunnelProviders: [NETunnelProviderManager]) {
         tunnels = tunnelProviders.map { TunnelContainer(tunnel: $0) }.sorted { TunnelsManager.tunnelNameIsLessThan($0.name, $1.name) }
@@ -406,7 +406,7 @@ class TunnelsManager {
     }
 
     private func startObservingTunnelStatuses() {
-        statusObservationToken = NotificationCenter.default.addObserver(forName: .NEVPNStatusDidChange, object: nil, queue: OperationQueue.main) { [weak self] statusChangeNotification in
+        statusObservationToken = NotificationCenter.default.observe(name: .NEVPNStatusDidChange, object: nil, queue: OperationQueue.main) { [weak self] statusChangeNotification in
             guard let self = self,
                 let session = statusChangeNotification.object as? NETunnelProviderSession,
                 let tunnelProvider = session.manager as? NETunnelProviderManager,
@@ -438,7 +438,7 @@ class TunnelsManager {
     }
 
     func startObservingTunnelConfigurations() {
-        configurationsObservationToken = NotificationCenter.default.addObserver(forName: .NEVPNConfigurationChange, object: nil, queue: OperationQueue.main) { [weak self] _ in
+        configurationsObservationToken = NotificationCenter.default.observe(name: .NEVPNConfigurationChange, object: nil, queue: OperationQueue.main) { [weak self] _ in
             DispatchQueue.main.async { [weak self] in
                 // We schedule reload() in a subsequent runloop to ensure that the completion handler of loadAllFromPreferences
                 // (reload() calls loadAllFromPreferences) is called after the completion handler of the saveToPreferences or
diff --git a/Sources/WireGuardApp/UI/macOS/ViewController/LogViewController.swift b/Sources/WireGuardApp/UI/macOS/ViewController/LogViewController.swift
index c3c8d87..ca4e575 100644
--- a/Sources/WireGuardApp/UI/macOS/ViewController/LogViewController.swift
+++ b/Sources/WireGuardApp/UI/macOS/ViewController/LogViewController.swift
@@ -18,6 +18,9 @@ class LogViewController: NSViewController {
         }
     }
 
+    private var boundsChangedNotificationToken: NotificationToken?
+    private var frameChangedNotificationToken: NotificationToken?
+
     let scrollView: NSScrollView = {
         let scrollView = NSScrollView()
         scrollView.hasVerticalScroller = true
@@ -104,13 +107,13 @@ class LogViewController: NSViewController {
         clipView.documentView = tableView
         scrollView.contentView = clipView
 
-        _ = NotificationCenter.default.addObserver(forName: NSView.boundsDidChangeNotification, object: clipView, queue: OperationQueue.main) { [weak self] _ in
+        boundsChangedNotificationToken = NotificationCenter.default.observe(name: NSView.boundsDidChangeNotification, object: clipView, queue: OperationQueue.main) { [weak self] _ in
             guard let self = self else { return }
             let lastVisibleRowIndex = self.tableView.row(at: NSPoint(x: 0, y: self.scrollView.contentView.documentVisibleRect.maxY - 1))
             self.isInScrolledToEndMode = lastVisibleRowIndex < 0 || lastVisibleRowIndex == self.logEntries.count - 1
         }
 
-        _ = NotificationCenter.default.addObserver(forName: NSView.frameDidChangeNotification, object: tableView, queue: OperationQueue.main) { [weak self] _ in
+        frameChangedNotificationToken = NotificationCenter.default.observe(name: NSView.frameDidChangeNotification, object: tableView, queue: OperationQueue.main) { [weak self] _ in
             guard let self = self else { return }
             if self.isInScrolledToEndMode {
                 DispatchQueue.main.async {
diff --git a/WireGuard.xcodeproj/project.pbxproj b/WireGuard.xcodeproj/project.pbxproj
index 1b282d2..d192148 100644
--- a/WireGuard.xcodeproj/project.pbxproj
+++ b/WireGuard.xcodeproj/project.pbxproj
@@ -7,6 +7,8 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		58233BCF2591F842002060A8 /* NotificationToken.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58233BCE2591F842002060A8 /* NotificationToken.swift */; };
+		58233BD02591F842002060A8 /* NotificationToken.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58233BCE2591F842002060A8 /* NotificationToken.swift */; };
 		585B105A2577E293004F691E /* InterfaceConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 585B10462577E293004F691E /* InterfaceConfiguration.swift */; };
 		585B105B2577E293004F691E /* InterfaceConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 585B10462577E293004F691E /* InterfaceConfiguration.swift */; };
 		585B105C2577E293004F691E /* InterfaceConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = 585B10462577E293004F691E /* InterfaceConfiguration.swift */; };
@@ -280,6 +282,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		58233BCE2591F842002060A8 /* NotificationToken.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationToken.swift; sourceTree = "<group>"; };
 		585B10462577E293004F691E /* InterfaceConfiguration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = InterfaceConfiguration.swift; sourceTree = "<group>"; };
 		585B10472577E293004F691E /* PeerConfiguration.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = PeerConfiguration.swift; sourceTree = "<group>"; };
 		585B10482577E293004F691E /* DNSServer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DNSServer.swift; sourceTree = "<group>"; };
@@ -344,6 +347,24 @@
 		6F6483E6229293300075BA15 /* LaunchedAtLoginDetector.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LaunchedAtLoginDetector.swift; sourceTree = "<group>"; };
 		6F689999218043390012E523 /* WireGuard-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "WireGuard-Bridging-Header.h"; sourceTree = "<group>"; };
 		6F70E20D221058DF008BDFB4 /* Base */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = Base; path = Sources/WireGuardApp/Base.lproj/InfoPlist.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFB5 /* fr */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fr; path = Sources/WireGuardApp/fr.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFB6 /* pl */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = pl; path = Sources/WireGuardApp/pl.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFB7 /* es */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = es; path = Sources/WireGuardApp/es.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFB8 /* ca */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ca; path = Sources/WireGuardApp/ca.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFB9 /* pa */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = pa; path = Sources/WireGuardApp/pa.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBA /* zh-Hans */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hans"; path = "Sources/WireGuardApp/zh-Hans.lproj/Localizable.strings"; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBB /* ja */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ja; path = Sources/WireGuardApp/ja.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBC /* it */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = it; path = Sources/WireGuardApp/it.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBD /* ro */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ro; path = Sources/WireGuardApp/ro.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBE /* fa */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fa; path = Sources/WireGuardApp/fa.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFBF /* fi */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fi; path = Sources/WireGuardApp/fi.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC0 /* ru */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ru; path = Sources/WireGuardApp/ru.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC1 /* ko */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ko; path = Sources/WireGuardApp/ko.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC2 /* tr */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = tr; path = Sources/WireGuardApp/tr.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC3 /* de */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = de; path = Sources/WireGuardApp/de.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC4 /* sl */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = sl; path = Sources/WireGuardApp/sl.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC5 /* id */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = id; path = Sources/WireGuardApp/id.lproj/Localizable.strings; sourceTree = "<group>"; };
+		6F70E20D221058DF008BDFC6 /* zh-Hant */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = "zh-Hant"; path = "Sources/WireGuardApp/zh-Hant.lproj/Localizable.strings"; sourceTree = "<group>"; };
 		6F70E22922106A2D008BDFB4 /* WireGuardLoginItemHelper.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = WireGuardLoginItemHelper.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		6F70E23222106A31008BDFB4 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		6F70E23922109BEF008BDFB4 /* LoginItemHelper.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = LoginItemHelper.entitlements; sourceTree = "<group>"; };
@@ -399,24 +420,6 @@
 		6FDEF801218646B900D8FBF6 /* ZipArchive.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZipArchive.swift; sourceTree = "<group>"; };
 		6FDEF805218725D200D8FBF6 /* SettingsTableViewController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SettingsTableViewController.swift; sourceTree = "<group>"; };
 		6FE1765521C90BBE002690EA /* Base */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = Base; path = Sources/WireGuardApp/Base.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC6 /* zh-Hant */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = zh-Hant; path = Sources/WireGuardApp/zh-Hant.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBA /* zh-Hans */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = zh-Hans; path = Sources/WireGuardApp/zh-Hans.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC5 /* id */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = id; path = Sources/WireGuardApp/id.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBC /* it */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = it; path = Sources/WireGuardApp/it.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC3 /* de */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = de; path = Sources/WireGuardApp/de.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFB5 /* fr */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fr; path = Sources/WireGuardApp/fr.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBF /* fi */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fi; path = Sources/WireGuardApp/fi.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBE /* fa */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = fa; path = Sources/WireGuardApp/fa.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC4 /* sl */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = sl; path = Sources/WireGuardApp/sl.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFB6 /* pl */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = pl; path = Sources/WireGuardApp/pl.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFB9 /* pa */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = pa; path = Sources/WireGuardApp/pa.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC1 /* ko */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ko; path = Sources/WireGuardApp/ko.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFB8 /* ca */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ca; path = Sources/WireGuardApp/ca.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC0 /* ru */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ru; path = Sources/WireGuardApp/ru.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBD /* ro */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ro; path = Sources/WireGuardApp/ro.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFC2 /* tr */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = tr; path = Sources/WireGuardApp/tr.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFBB /* ja */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = ja; path = Sources/WireGuardApp/ja.lproj/Localizable.strings; sourceTree = "<group>"; };
-		6F70E20D221058DF008BDFB7 /* es */ = {isa = PBXFileReference; lastKnownFileType = text.plist.strings; name = es; path = Sources/WireGuardApp/es.lproj/Localizable.strings; sourceTree = "<group>"; };
 		6FE1765921C90E87002690EA /* LocalizationHelper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LocalizationHelper.swift; sourceTree = "<group>"; };
 		6FE254FA219C10800028284D /* ZipImporter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ZipImporter.swift; sourceTree = "<group>"; };
 		6FE254FE219C60290028284D /* ZipExporter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ZipExporter.swift; sourceTree = "<group>"; };
@@ -580,6 +583,7 @@
 				6F7774E6217201E0006A79B3 /* Model */,
 				6F5A2B4421AFDE020081EDD8 /* FileManager+Extension.swift */,
 				6B5C5E26220A48D30024272E /* Keychain.swift */,
+				58233BCE2591F842002060A8 /* NotificationToken.swift */,
 			);
 			name = Shared;
 			path = Sources/Shared;
@@ -1289,6 +1293,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				58233BD02591F842002060A8 /* NotificationToken.swift in Sources */,
 				6FBA101521D613F90051C35F /* Application.swift in Sources */,
 				6FB1BDCC21D50F5300A991BF /* TunnelsManager.swift in Sources */,
 				6F8F0D7222258153000E8335 /* ActivateOnDemandViewModel.swift in Sources */,
@@ -1442,6 +1447,7 @@
 				6F61F1EB21B937EF00483816 /* WireGuardResult.swift in Sources */,
 				6F7774F321774263006A79B3 /* TunnelEditTableViewController.swift in Sources */,
 				6FBA103B21D6B4290051C35F /* ErrorPresenterProtocol.swift in Sources */,
+				58233BCF2591F842002060A8 /* NotificationToken.swift in Sources */,
 				585B10862577E294004F691E /* IPAddressRange.swift in Sources */,
 				6FDEF802218646BA00D8FBF6 /* ZipArchive.swift in Sources */,
 				585B10922577E294004F691E /* key.c in Sources */,