Transparent ShutdownManager with cascading ShutdownTrackers (#6040)

* Idea for transparent ShutdownManager use

* Tracker hierarchies

* Fix wasm shutdown, convinience shutdown method

wasm/client/src/client.rs

@@ -28,7 +28,7 @@ use wasm_client_core::helpers::{
     add_gateway, generate_new_client_keys, parse_recipient, parse_sender_tag,
 };
 use wasm_client_core::nym_task::connections::TransmissionLane;
-use wasm_client_core::nym_task::ShutdownManager;
+use wasm_client_core::nym_task::ShutdownTracker;
 use wasm_client_core::storage::core_client_traits::FullWasmClientStorage;
 use wasm_client_core::storage::wasm_client_traits::WasmClientStorage;
 use wasm_client_core::storage::ClientStorage;
@@ -59,7 +59,7 @@ pub struct NymClient {
 
     // even though we don't use graceful shutdowns, other components rely on existence of this struct
     // and if it's dropped, everything will start going offline
-    _task_manager: ShutdownManager,
+    _task_manager: ShutdownTracker,
 
     packet_type: PacketType,
 }

wasm/mix-fetch/src/client.rs

@@ -20,7 +20,7 @@ use wasm_client_core::client::base_client::{BaseClientBuilder, ClientInput, Clie
 use wasm_client_core::client::inbound_messages::InputMessage;
 use wasm_client_core::helpers::{add_gateway, generate_new_client_keys};
 use wasm_client_core::nym_task::connections::TransmissionLane;
-use wasm_client_core::nym_task::ShutdownManager;
+use wasm_client_core::nym_task::ShutdownTracker;
 use wasm_client_core::storage::core_client_traits::FullWasmClientStorage;
 use wasm_client_core::storage::wasm_client_traits::WasmClientStorage;
 use wasm_client_core::storage::ClientStorage;
@@ -41,7 +41,7 @@ pub struct MixFetchClient {
     requests: ActiveRequests,
 
     // this has to be guarded by a mutex to be able to disconnect with an immutable reference
-    _shutdown_manager: Mutex<ShutdownManager>,
+    _shutdown_manager: Mutex<ShutdownTracker>,
 }
 
 #[wasm_bindgen]
@@ -233,11 +233,11 @@ impl MixFetchClient {
         self.invalidated.store(true, Ordering::Relaxed);
 
         console_log!("sending shutdown signal");
-        let mut shutdown_guard = self._shutdown_manager.lock().await;
-        shutdown_guard.send_cancellation();
-
+        let shutdown_guard = self._shutdown_manager.lock().await;
+        shutdown_guard.clone_shutdown_token().cancel();
+        shutdown_guard.close_tracker();
         console_log!("waiting for shutdown to complete");
-        shutdown_guard.run_until_shutdown().await;
+        shutdown_guard.wait_for_tracker().await;
 
         self.requests.invalidate_all().await;