[Jobs]: Expose CancelAndDetach()

This is useful for wasm instead of keeping around a list of handles.

Change-Id: I4ef970ba191a66303c577bbe8e6ab1327aad2e24
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2451209
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70353}

include/v8-platform.h

@@ -216,6 +216,14 @@ class JobHandle {
    */
   virtual void Cancel() = 0;
 
+  /*
+   * Forces all existing workers to yield ASAP but doesn’t wait for them.
+   * Warning, this is dangerous if the Job's callback is bound to or has access
+   * to state which may be deleted after this call.
+   * TODO(etiennep): Cleanup once implemented by all embedders.
+   */
+  virtual void CancelAndDetach() { Cancel(); }
+
   /**
    * Returns true if there's no work pending and no worker running.
    */

src/heap/cppgc/default-job.h

@@ -64,6 +64,8 @@ class DefaultJobImpl {
     Join();
   }
 
+  void CancelAndDetach() { can_run_.store(false, std::memory_order_relaxed); }
+
   bool IsCompleted() const { return !IsRunning(); }
   bool IsRunning() const {
     uint8_t active_threads = active_threads_.load(std::memory_order_relaxed);
@@ -173,6 +175,7 @@ class DefaultJobImpl<Thread>::JobHandle final : public cppgc::JobHandle {
   }
   void Join() override { job_->Join(); }
   void Cancel() override { job_->Cancel(); }
+  void CancelAndDetach() override { job_->CancelAndDetach(); }
   bool IsCompleted() override { return job_->IsCompleted(); }
   bool IsRunning() override { return job_->IsRunning(); }
 

src/libplatform/default-job.cc

@@ -122,6 +122,11 @@ void DefaultJobState::CancelAndWait() {
   }
 }
 
+void DefaultJobState::CancelAndDetach() {
+  base::MutexGuard guard(&mutex_);
+  is_canceled_.store(true, std::memory_order_relaxed);
+}
+
 bool DefaultJobState::IsCompleted() {
   base::MutexGuard guard(&mutex_);
   return job_task_->GetMaxConcurrency(active_workers_) == 0 &&
@@ -220,6 +225,11 @@ void DefaultJobHandle::Cancel() {
   state_ = nullptr;
 }
 
+void DefaultJobHandle::CancelAndDetach() {
+  state_->CancelAndDetach();
+  state_ = nullptr;
+}
+
 bool DefaultJobHandle::IsCompleted() { return state_->IsCompleted(); }
 
 }  // namespace platform

src/libplatform/default-job.h

@@ -54,6 +54,7 @@ class V8_PLATFORM_EXPORT DefaultJobState
 
   void Join();
   void CancelAndWait();
+  void CancelAndDetach();
   bool IsCompleted();
 
   // Must be called before running |job_task_| for the first time. If it returns
@@ -109,6 +110,7 @@ class V8_PLATFORM_EXPORT DefaultJobHandle : public JobHandle {
 
   void Join() override;
   void Cancel() override;
+  void CancelAndDetach() override;
   bool IsCompleted() override;
   bool IsRunning() override { return state_ != nullptr; }
 

test/cctest/wasm/test-streaming-compilation.cc

@@ -111,6 +111,7 @@ class MockPlatform final : public TestPlatform {
     }
     void Join() override { orig_handle_->Join(); }
     void Cancel() override { orig_handle_->Cancel(); }
+    void CancelAndDetach() override { orig_handle_->CancelAndDetach(); }
     bool IsCompleted() override { return orig_handle_->IsCompleted(); }
     bool IsRunning() override { return orig_handle_->IsRunning(); }
 

test/cctest/wasm/test-wasm-metrics.cc

@@ -114,6 +114,7 @@ class MockPlatform final : public TestPlatform {
     }
     void Join() override { orig_handle_->Join(); }
     void Cancel() override { orig_handle_->Cancel(); }
+    void CancelAndDetach() override { orig_handle_->CancelAndDetach(); }
     bool IsRunning() override { return orig_handle_->IsRunning(); }
     bool IsCompleted() override { return orig_handle_->IsCompleted(); }