1 files changed, 87 insertions, 0 deletions
diff --git a/system/common/handler.cc b/system/common/handler.cc
new file mode 100644
index 0000000000..219dd82dde
--- /dev/null
+++ b/system/common/handler.cc
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * 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 "handler.h"
+
+#include <sys/eventfd.h>
+#include <cstring>
+
+#include "base/logging.h"
+
+#include "reactor.h"
+#include "utils.h"
+
+#ifndef EFD_SEMAPHORE
+#define EFD_SEMAPHORE 1
+#endif
+
+namespace bluetooth {
+namespace common {
+
+Handler::Handler(Thread* thread)
+  : thread_(thread),
+    fd_(eventfd(0, EFD_SEMAPHORE | EFD_NONBLOCK)) {
+  CHECK_NE(fd_, -1) << __func__ << ": cannot create eventfd: " << strerror(errno);
+
+  reactable_ = thread_->GetReactor()->Register(fd_, [this] { this->handle_next_event(); }, nullptr);
+}
+
+Handler::~Handler() {
+  thread_->GetReactor()->Unregister(reactable_);
+  reactable_ = nullptr;
+
+  int close_status;
+  RUN_NO_INTR(close_status = close(fd_));
+  CHECK_NE(close_status, -1) << __func__ << ": cannot close eventfd: " << strerror(errno);
+}
+
+void Handler::Post(Closure closure) {
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    tasks_.emplace(std::move(closure));
+  }
+  uint64_t val = 1;
+  auto write_result = eventfd_write(fd_, val);
+  CHECK_NE(write_result, -1) << __func__ << ": failed to write: " << strerror(errno);
+}
+
+void Handler::Clear() {
+  std::lock_guard<std::mutex> lock(mutex_);
+
+  std::queue<Closure> empty;
+  std::swap(tasks_, empty);
+
+  uint64_t val;
+  while (eventfd_read(fd_, &val) == 0) {
+  }
+}
+
+void Handler::handle_next_event() {
+  Closure closure;
+  uint64_t val = 0;
+  auto read_result = eventfd_read(fd_, &val);
+  CHECK_NE(read_result, -1) << __func__ << ": failed to read fd: " << strerror(errno);
+
+  {
+    std::lock_guard<std::mutex> lock(mutex_);
+    closure = std::move(tasks_.front());
+    tasks_.pop();
+  }
+  closure();
+}
+
+}  // namespace common
+}  // namespace bluetooth