chore: import upstream snapshot with attribution

paddle/phi/backends/callback_manager.cc

@@ -0,0 +1,54 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/phi/backends/callback_manager.h"
+
+#include <ThreadPool.h>
+
+#include "paddle/phi/backends/device_guard.h"
+#include "paddle/phi/core/enforce.h"
+
+namespace phi {
+
+CallbackManager::CallbackManager(stream::Stream *stream)
+    : stream_(stream), thread_pool_(new ::ThreadPool(1)) {}
+
+void CallbackManager::AddCallback(std::function<void()> callback) const {
+  auto *callback_func = new std::function<void()>(std::move(callback));
+  auto *func = new std::function<void()>([this, callback_func] {
+    std::lock_guard<std::mutex> lock(mtx_);
+    last_future_ = thread_pool_->enqueue([callback_func] {
+      std::unique_ptr<std::function<void()>> releaser(callback_func);
+      (*callback_func)();
+    });
+  });
+  phi::DeviceGuard guard(stream_->GetPlace());
+  DeviceManager::GetDeviceWithPlace(stream_->GetPlace())
+      ->AddCallback(stream_, func);
+}
+
+void CallbackManager::Wait() const {
+  phi::DeviceGuard guard(stream_->GetPlace());
+  DeviceManager::GetDeviceWithPlace(stream_->GetPlace())
+      ->SynchronizeStream(stream_->raw_stream());
+
+  {
+    std::lock_guard<std::mutex> lock(mtx_);
+    if (last_future_.valid()) {
+      last_future_.wait();
+    }
+  }
+}
+
+}  // namespace phi