Tunnel: move state change into interface

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/backend/Backend.java

@@ -60,22 +60,4 @@ public interface Backend {
      * @return The updated state of the tunnel.
      */
     Tunnel.State setState(Tunnel tunnel, Tunnel.State state, @Nullable Config config) throws Exception;
-
-    interface TunnelStateChangeNotificationReceiver {
-        void tunnelStateChange(Tunnel tunnel, Tunnel.State state);
-    }
-
-    /**
-     * Register a state change notification callback.
-     *
-     * @param receiver The receiver object to receive the notification.
-     */
-    void registerStateChangeNotification(TunnelStateChangeNotificationReceiver receiver);
-
-    /**
-     * Unregister a state change notification callback.
-     *
-     * @param receiver The receiver object to no longer receive the notification.
-     */
-    void unregisterStateChangeNotification(TunnelStateChangeNotificationReceiver receiver);
 }

app/src/main/java/com/wireguard/android/backend/GoBackend.java

@@ -5,7 +5,6 @@
 
 package com.wireguard.android.backend;
 
-import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
@@ -25,7 +24,6 @@ import com.wireguard.crypto.KeyFormatException;
 
 import java.net.InetAddress;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -48,8 +46,6 @@ public final class GoBackend implements Backend {
     @Nullable private Config currentConfig;
     private int currentTunnelHandle = -1;
 
-    private final Set<TunnelStateChangeNotificationReceiver> notifiers = new HashSet<>();
-
     public GoBackend(final Context context) {
         SharedLibraryLoader.loadSharedLibrary(context, "wg-go");
         this.context = context;
@@ -240,8 +236,7 @@ public final class GoBackend implements Backend {
             currentConfig = null;
         }
 
-        for (final TunnelStateChangeNotificationReceiver notifier : notifiers)
-            notifier.tunnelStateChange(tunnel, state);
+        tunnel.onStateChange(state);
     }
 
     private void startVpnService() {
@@ -249,16 +244,6 @@ public final class GoBackend implements Backend {
         context.startService(new Intent(context, VpnService.class));
     }
 
-    @Override
-    public void registerStateChangeNotification(final TunnelStateChangeNotificationReceiver receiver) {
-        notifiers.add(receiver);
-    }
-
-    @Override
-    public void unregisterStateChangeNotification(final TunnelStateChangeNotificationReceiver receiver) {
-        notifiers.remove(receiver);
-    }
-
     public static class VpnService extends android.net.VpnService {
         @Nullable private GoBackend owner;
 
@@ -286,8 +271,7 @@ public final class GoBackend implements Backend {
                     owner.currentTunnel = null;
                     owner.currentTunnelHandle = -1;
                     owner.currentConfig = null;
-                    for (final TunnelStateChangeNotificationReceiver notifier : owner.notifiers)
-                        notifier.tunnelStateChange(tunnel, State.DOWN);
+                    tunnel.onStateChange(State.DOWN);
                 }
             }
             vpnService = vpnService.newIncompleteFuture();

app/src/main/java/com/wireguard/android/backend/Tunnel.java

@@ -29,5 +29,18 @@ public interface Tunnel {
         return !NAME_PATTERN.matcher(name).matches();
     }
 
+    /**
+     * Get the name of the tunnel, which should always pass the !isNameInvalid test.
+     *
+     * @return The name of the tunnel.
+     */
     String getName();
+
+    /**
+     * React to a change in state of the tunnel. Should only be directly called by Backend.
+     *
+     * @param newState The new state of the tunnel.
+     * @return The new state of the tunnel.
+     */
+    void onStateChange(State newState);
 }

app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java

@@ -23,7 +23,6 @@ import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -45,7 +44,6 @@ public final class WgQuickBackend implements Backend {
     private final ToolsInstaller toolsInstaller;
     private final File localTemporaryDir;
     private final Map<Tunnel, Config> runningConfigs = new HashMap<>();
-    private final Set<TunnelStateChangeNotificationReceiver> notifiers = new HashSet<>();
 
     public WgQuickBackend(final Context context, final RootShell rootShell, final ToolsInstaller toolsInstaller) {
         localTemporaryDir = new File(context.getCacheDir(), "tmp");
@@ -155,17 +153,6 @@ public final class WgQuickBackend implements Backend {
         else
             runningConfigs.remove(tunnel);
 
-        for (final TunnelStateChangeNotificationReceiver notifier : notifiers)
-            notifier.tunnelStateChange(tunnel, state);
-    }
-
-    @Override
-    public void registerStateChangeNotification(final TunnelStateChangeNotificationReceiver receiver) {
-        notifiers.add(receiver);
-    }
-
-    @Override
-    public void unregisterStateChangeNotification(final TunnelStateChangeNotificationReceiver receiver) {
-        notifiers.remove(receiver);
+        tunnel.onStateChange(state);
     }
 }

app/src/main/java/com/wireguard/android/model/ObservableTunnel.java

@@ -96,7 +96,7 @@ public class ObservableTunnel extends BaseObservable implements Keyed<String>, T
         return config;
     }
 
-    public String onNameChanged(final String name) {
+    String onNameChanged(final String name) {
         this.name = name;
         notifyPropertyChanged(BR.name);
         return name;
@@ -110,6 +110,11 @@ public class ObservableTunnel extends BaseObservable implements Keyed<String>, T
         return state;
     }
 
+    @Override
+    public void onStateChange(final State newState) {
+        onStateChanged(state);
+    }
+
     @Nullable
     Statistics onStatisticsChanged(@Nullable final Statistics statistics) {
         this.statistics = statistics;

app/src/main/java/com/wireguard/android/model/TunnelManager.java

@@ -15,7 +15,6 @@ import androidx.annotation.Nullable;
 import com.wireguard.android.Application;
 import com.wireguard.android.BR;
 import com.wireguard.android.R;
-import com.wireguard.android.backend.Backend.TunnelStateChangeNotificationReceiver;
 import com.wireguard.android.configStore.ConfigStore;
 import com.wireguard.android.backend.Tunnel;
 import com.wireguard.android.backend.Tunnel.State;
@@ -40,7 +39,7 @@ import java9.util.stream.StreamSupport;
  * Maintains and mediates changes to the set of available WireGuard tunnels,
  */
 
-public final class TunnelManager extends BaseObservable implements TunnelStateChangeNotificationReceiver {
+public final class TunnelManager extends BaseObservable {
     private static final Comparator<String> COMPARATOR = Comparators.<String>thenComparing(
             String.CASE_INSENSITIVE_ORDER, Comparators.naturalOrder());
     private static final String KEY_LAST_USED_TUNNEL = "last_used_tunnel";
@@ -57,13 +56,6 @@ public final class TunnelManager extends BaseObservable implements TunnelStateCh
 
     public TunnelManager(final ConfigStore configStore) {
         this.configStore = configStore;
-        Application.getBackendAsync().thenAccept(backend -> backend.registerStateChangeNotification(this));
-    }
-
-    @Override
-    protected void finalize() throws Throwable {
-        Application.getBackendAsync().thenAccept(backend -> backend.unregisterStateChangeNotification(this));
-        super.finalize();
     }
 
     static CompletionStage<State> getTunnelState(final ObservableTunnel tunnel) {
@@ -266,11 +258,6 @@ public final class TunnelManager extends BaseObservable implements TunnelStateCh
         });
     }
 
-    @Override
-    public void tunnelStateChange(final Tunnel tunnel, final State state) {
-        ((ObservableTunnel)tunnel).onStateChanged(state);
-    }
-
     public static final class IntentReceiver extends BroadcastReceiver {
         @Override
         public void onReceive(final Context context, @Nullable final Intent intent) {