From a0a6bf78b83c9cd49d0be58dab36c9a39577e0e9 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Fri, 27 Sep 2024 11:51:59 +0200
Subject: [PATCH] handle idle end event for idle detection in persisting

---
 .../turbo-tasks-backend/src/backend/mod.rs    | 27 ++++++++++++++-----
 turbopack/crates/turbo-tasks/src/backend.rs   |  2 ++
 turbopack/crates/turbo-tasks/src/manager.rs   |  1 +
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs b/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs
index 2768d09a3a6b4a..eb807c93b6a6f2 100644
--- a/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs
+++ b/turbopack/crates/turbo-tasks-backend/src/backend/mod.rs
@@ -129,7 +129,8 @@ struct TurboTasksBackendInner {
 
     stopping: AtomicBool,
     stopping_event: Event,
-    idle_event: Event,
+    idle_start_event: Event,
+    idle_end_event: Event,
 
     backing_storage: Arc<dyn BackingStorage + Sync + Send>,
 }
@@ -167,7 +168,8 @@ impl TurboTasksBackendInner {
             last_snapshot: AtomicU64::new(0),
             stopping: AtomicBool::new(false),
             stopping_event: Event::new(|| "TurboTasksBackend::stopping_event".to_string()),
-            idle_event: Event::new(|| "TurboTasksBackend::idle_event".to_string()),
+            idle_start_event: Event::new(|| "TurboTasksBackend::idle_start_event".to_string()),
+            idle_end_event: Event::new(|| "TurboTasksBackend::idle_end_event".to_string()),
             backing_storage,
         }
     }
@@ -630,7 +632,11 @@ impl TurboTasksBackendInner {
     }
 
     fn idle_start(&self) {
-        self.idle_event.notify(usize::MAX);
+        self.idle_start_event.notify(usize::MAX);
+    }
+
+    fn idle_end(&self) {
+        self.idle_end_event.notify(usize::MAX);
     }
 
     fn get_or_create_persistent_task(
@@ -1170,16 +1176,21 @@ impl TurboTasksBackendInner {
                     if until > Instant::now() {
                         let mut stop_listener = self.stopping_event.listen();
                         if !self.stopping.load(Ordering::Acquire) {
-                            let mut idle_listener = self.idle_event.listen();
+                            let mut idle_start_listener = self.idle_start_event.listen();
+                            let mut idle_end_listener = self.idle_end_event.listen();
                             let mut idle_time = until + IDLE_TIMEOUT;
                             loop {
                                 tokio::select! {
                                     _ = &mut stop_listener => {
                                         break;
                                     },
-                                    _ = &mut idle_listener => {
+                                    _ = &mut idle_start_listener => {
                                         idle_time = Instant::now() + IDLE_TIMEOUT;
-                                        idle_listener = self.idle_event.listen()
+                                        idle_start_listener = self.idle_start_event.listen()
+                                    },
+                                    _ = &mut idle_end_listener => {
+                                        idle_time = until + IDLE_TIMEOUT;
+                                        idle_end_listener = self.idle_end_event.listen()
                                     },
                                     _ = tokio::time::sleep_until(until.into()) => {
                                         break;
@@ -1300,6 +1311,10 @@ impl Backend for TurboTasksBackend {
         self.0.idle_start();
     }
 
+    fn idle_end(&self, _turbo_tasks: &dyn TurboTasksBackendApi<Self>) {
+        self.0.idle_end();
+    }
+
     fn get_or_create_persistent_task(
         &self,
         task_type: CachedTaskType,
diff --git a/turbopack/crates/turbo-tasks/src/backend.rs b/turbopack/crates/turbo-tasks/src/backend.rs
index 1485a38fb634a7..e73c08d4e268c3 100644
--- a/turbopack/crates/turbo-tasks/src/backend.rs
+++ b/turbopack/crates/turbo-tasks/src/backend.rs
@@ -534,6 +534,8 @@ pub trait Backend: Sync + Send {
 
     #[allow(unused_variables)]
     fn idle_start(&self, turbo_tasks: &dyn TurboTasksBackendApi<Self>) {}
+    #[allow(unused_variables)]
+    fn idle_end(&self, turbo_tasks: &dyn TurboTasksBackendApi<Self>) {}
 
     fn invalidate_task(&self, task: TaskId, turbo_tasks: &dyn TurboTasksBackendApi<Self>);
 
diff --git a/turbopack/crates/turbo-tasks/src/manager.rs b/turbopack/crates/turbo-tasks/src/manager.rs
index 8231e10fa83abb..8d165c8cb19de5 100644
--- a/turbopack/crates/turbo-tasks/src/manager.rs
+++ b/turbopack/crates/turbo-tasks/src/manager.rs
@@ -851,6 +851,7 @@ impl<B: Backend + 'static> TurboTasks<B> {
         {
             *self.start.lock().unwrap() = Some(Instant::now());
             self.event_start.notify(usize::MAX);
+            self.backend.idle_end(self);
         }
     }