Add Device to Device Transfer UI.

app/src/main/java/org/thoughtcrime/securesms/net/DeviceTransferBlockingInterceptor.java

@@ -0,0 +1,55 @@
+package org.thoughtcrime.securesms.net;
+
+import androidx.annotation.NonNull;
+
+import org.signal.core.util.logging.Log;
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
+
+import java.io.IOException;
+
+import okhttp3.Interceptor;
+import okhttp3.Protocol;
+import okhttp3.Response;
+import okhttp3.ResponseBody;
+
+/**
+ * Provide a way to block network access while performing a device transfer.
+ */
+public final class DeviceTransferBlockingInterceptor implements Interceptor {
+
+  private static final String TAG = Log.tag(DeviceTransferBlockingInterceptor.class);
+
+  private static final DeviceTransferBlockingInterceptor INSTANCE = new DeviceTransferBlockingInterceptor();
+
+  private volatile boolean blockNetworking = false;
+
+  public static DeviceTransferBlockingInterceptor getInstance() {
+    return INSTANCE;
+  }
+
+  @Override
+  public @NonNull Response intercept(@NonNull Chain chain) throws IOException {
+    if (!blockNetworking) {
+      return chain.proceed(chain.request());
+    }
+
+    Log.w(TAG, "Preventing request because in transfer mode.");
+    return new Response.Builder().request(chain.request())
+                                 .protocol(Protocol.HTTP_1_1)
+                                 .receivedResponseAtMillis(System.currentTimeMillis())
+                                 .message("")
+                                 .body(ResponseBody.create(null, ""))
+                                 .code(500)
+                                 .build();
+  }
+
+  public void blockNetwork() {
+    blockNetworking = true;
+    ApplicationDependencies.closeConnections();
+  }
+
+  public void unblockNetwork() {
+    blockNetworking = false;
+    ApplicationDependencies.getIncomingMessageObserver();
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/net/PipeConnectivityListener.java

@@ -68,7 +68,7 @@ public class PipeConnectivityListener implements ConnectivityListener {
 
     if (SignalStore.proxy().isProxyEnabled()) {
       Log.w(TAG, "Encountered an error while we had a proxy set! Terminating the connection to prevent retry spam.");
-      ApplicationDependencies.closeConnectionsAfterProxyFailure();
+      ApplicationDependencies.closeConnections();
       return false;
     } else {
       return true;