add 10s timeout

lib/electrumx_rpc/electrumx_chain_height_service.dart

@@ -4,11 +4,15 @@ import 'package:stackwallet/utilities/enums/coin_enum.dart';
 
 /// Store chain height subscriptions for each coin.
 abstract class ElectrumxChainHeightService {
-  static Map<Coin, StreamSubscription<dynamic>?> subscriptions = {};
   // Used to hold chain height subscriptions for each coin as in:
   // ElectrumxChainHeightService.subscriptions[cryptoCurrency.coin] = sub;
+  static Map<Coin, StreamSubscription<dynamic>?> subscriptions = {};
 
-  static Map<Coin, Completer<int>?> completers = {};
   // Used to hold chain height completers for each coin as in:
   // ElectrumxChainHeightService.completers[cryptoCurrency.coin] = completer;
+  static Map<Coin, Completer<int>?> completers = {};
+
+  // Used to hold the time each coin started waiting for chain height as in:
+  // ElectrumxChainHeightService.timeStarted[cryptoCurrency.coin] = time;
+  static Map<Coin, DateTime?> timeStarted = {};
 }

lib/wallets/wallet/wallet_mixin_interfaces/electrumx_interface.dart

@@ -825,6 +825,9 @@ mixin ElectrumXInterface<T extends Bip39HDCurrency> on Bip39HDWallet<T> {
   }
 
   Future<void> _manageChainHeightSubscription() async {
+    // Set the timeout period for the chain height subscription.
+    const timeout = Duration(seconds: 10);
+
     if (ElectrumxChainHeightService.subscriptions[cryptoCurrency.coin] ==
         null) {
       // No subscription exists for this coin yet, so create one.
@@ -840,6 +843,11 @@ mixin ElectrumXInterface<T extends Bip39HDCurrency> on Bip39HDWallet<T> {
       final subscription =
           subscribableElectrumXClient.subscribeToBlockHeaders();
 
+      // Set the time the subscription was created.
+      final subscriptionCreationTime = DateTime.now();
+      ElectrumxChainHeightService.timeStarted[cryptoCurrency.coin] =
+          subscriptionCreationTime;
+
       // Set stream subscription.
       ElectrumxChainHeightService.subscriptions[cryptoCurrency.coin] =
           subscription.responseStream.asBroadcastStream().listen((event) {
@@ -910,6 +918,25 @@ mixin ElectrumXInterface<T extends Bip39HDCurrency> on Bip39HDWallet<T> {
       }
     }
 
+    // Check if the subscription has been running for too long.
+    if (ElectrumxChainHeightService.timeStarted[cryptoCurrency.coin] != null) {
+      final timeRunning = DateTime.now().difference(
+          ElectrumxChainHeightService.timeStarted[cryptoCurrency.coin]!);
+      // Cancel and retry if we've been waiting too long.
+      if (timeRunning > timeout) {
+        // Clear this coin's subscription.
+        await ElectrumxChainHeightService.subscriptions[cryptoCurrency.coin]!
+            .cancel();
+        ElectrumxChainHeightService.subscriptions[cryptoCurrency.coin] = null;
+
+        // Clear this coin's completer.
+        ElectrumxChainHeightService.completers[cryptoCurrency.coin] = null;
+
+        // Retry/recurse.
+        return await _manageChainHeightSubscription();
+      }
+    }
+
     // Wait for the first response.
     _latestHeight = await ElectrumxChainHeightService
         .completers[cryptoCurrency.coin]!.future;