Restart websocket immediately upon network change.

app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt

@@ -3,11 +3,8 @@ package org.thoughtcrime.securesms.messages
 import android.annotation.SuppressLint
 import android.app.Application
 import android.app.Service
-import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
-import android.content.IntentFilter
-import android.net.ConnectivityManager
 import android.os.IBinder
 import androidx.annotation.VisibleForTesting
 import androidx.core.app.NotificationCompat
@@ -87,10 +84,19 @@ class IncomingMessageObserver(private val context: Application) {
 
   private val decryptionDrainedListeners: MutableList<Runnable> = CopyOnWriteArrayList()
   private val keepAliveTokens: MutableMap<String, Long> = mutableMapOf()
-  private val connectionReceiver: BroadcastReceiver
 
   private val lock: ReentrantLock = ReentrantLock()
   private val connectionNecessarySemaphore = Semaphore(0)
+  private val networkConnectionListener = NetworkConnectionListener(context) { isNetworkAvailable ->
+    lock.withLock {
+      if (isNetworkAvailable()) {
+        Log.w(TAG, "Lost network connection. Shutting down our websocket connections and resetting the drained state.")
+        decryptionDrained = false
+        disconnect()
+      }
+      connectionNecessarySemaphore.release()
+    }
+  }
 
   private val messageContentProcessor = MessageContentProcessorV2(context)
 
@@ -136,20 +142,7 @@ class IncomingMessageObserver(private val context: Application) {
       }
     })
 
-    connectionReceiver = object : BroadcastReceiver() {
-      override fun onReceive(context: Context, intent: Intent) {
-        lock.withLock {
-          if (!NetworkConstraint.isMet(context)) {
-            Log.w(TAG, "Lost network connection. Shutting down our websocket connections and resetting the drained state.")
-            decryptionDrained = false
-            disconnect()
-          }
-          connectionNecessarySemaphore.release()
-        }
-      }
-    }
-
-    context.registerReceiver(connectionReceiver, IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION))
+    networkConnectionListener.register()
   }
 
   fun notifyRegistrationChanged() {
@@ -250,8 +243,7 @@ class IncomingMessageObserver(private val context: Application) {
   fun terminateAsync() {
     Log.w(TAG, "Termination Enqueued! ${this.hashCode()}", Throwable())
     INSTANCE_COUNT.decrementAndGet()
-    context.unregisterReceiver(connectionReceiver)
-
+    networkConnectionListener.unregister()
     SignalExecutors.BOUNDED.execute {
       Log.w(TAG, "Beginning termination. ${this.hashCode()}")
       terminated = true

app/src/main/java/org/thoughtcrime/securesms/messages/NetworkConnectionListener.kt

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.messages
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.net.ConnectivityManager
+import android.net.Network
+import android.os.Build
+import org.signal.core.util.logging.Log
+import org.thoughtcrime.securesms.jobmanager.impl.NetworkConstraint
+import org.thoughtcrime.securesms.util.ServiceUtil
+
+/**
+ * Backcompat listener for determining when the network connection is lost.
+ * On API 28+, [onNetworkLost] is invoked when the system notifies the app that the network is lost.
+ * On earlier versions, [onNetworkLost] is invoked on any network change (gained, lost, losing, etc)
+ * Therefore, [onNetworkLost] is a higher-order function, which takes a function to determine conditionally if it should run.
+ * API 28+ only runs on lost networks, so it provides a conditional that's always true because that is guaranteed by the call site.
+ * Earlier versions use [NetworkConstraint.isMet] to query the current network state upon receiving the broadcast.
+ */
+class NetworkConnectionListener(private val context: Context, private val onNetworkLost: (() -> Boolean) -> Unit) {
+  companion object {
+    private val TAG = Log.tag(NetworkConnectionListener::class.java)
+  }
+
+  private val connectivityManager = ServiceUtil.getConnectivityManager(context)
+
+  private val networkChangedCallback: ConnectivityManager.NetworkCallback = object : ConnectivityManager.NetworkCallback() {
+    override fun onUnavailable() {
+      super.onUnavailable()
+      Log.d(TAG, "ConnectivityManager.NetworkCallback onUnavailable()")
+      onNetworkLost { true }
+    }
+
+    override fun onAvailable(network: Network) {
+      super.onAvailable(network)
+      Log.d(TAG, "ConnectivityManager.NetworkCallback onAvailable()")
+      onNetworkLost { false }
+    }
+
+    override fun onLost(network: Network) {
+      super.onLost(network)
+      Log.d(TAG, "ConnectivityManager.NetworkCallback onLost()")
+      onNetworkLost { true }
+    }
+  }
+
+  private val connectionReceiver = object : BroadcastReceiver() {
+    override fun onReceive(context: Context, intent: Intent) {
+      Log.d(TAG, "BroadcastReceiver onReceive().")
+      onNetworkLost { !NetworkConstraint.isMet(context) }
+    }
+  }
+
+  fun register() {
+    if (Build.VERSION.SDK_INT >= 28) {
+      connectivityManager.registerDefaultNetworkCallback(networkChangedCallback)
+    } else {
+      context.registerReceiver(connectionReceiver, IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION))
+    }
+  }
+
+  fun unregister() {
+    if (Build.VERSION.SDK_INT >= 28) {
+      connectivityManager.unregisterNetworkCallback(networkChangedCallback)
+    } else {
+      context.unregisterReceiver(connectionReceiver)
+    }
+  }
+}

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

@@ -5,8 +5,6 @@ import android.app.Application;
 import androidx.annotation.NonNull;
 
 import org.signal.core.util.logging.Log;
-import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
-import org.thoughtcrime.securesms.keyvalue.SignalStore;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 import org.whispersystems.signalservice.api.SignalWebSocket;
 import org.whispersystems.signalservice.api.util.Preconditions;