Default implementation for CAN bus HAL

This implementation supports SocketCAN interfaces.

Bug: 135918744
Test: VTS (separate new change)
Change-Id: I12b93e37fa64e341bee2c64eaf130b39977fcef5
diff --git a/automotive/can/1.0/default/CloseHandle.h b/automotive/can/1.0/default/CloseHandle.h
new file mode 100644
index 0000000..94972e0
--- /dev/null
+++ b/automotive/can/1.0/default/CloseHandle.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#pragma once
+
+#include <android-base/macros.h>
+#include <android/hardware/automotive/can/1.0/ICloseHandle.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace can {
+namespace V1_0 {
+namespace implementation {
+
+/**
+ * Generic ICloseHandle implementation ignoring double-close events.
+ */
+struct CloseHandle : public ICloseHandle {
+    using Callback = std::function<void()>;
+
+    /**
+     * Create a handle with a callback.
+     *
+     * The callback is guaranteed to be called exactly once.
+     *
+     * \param callback Called on the first close() call, or on destruction of the handle
+     */
+    CloseHandle(Callback callback);
+    virtual ~CloseHandle();
+
+    Return<void> close() override;
+
+  private:
+    Callback mCallback;
+    std::atomic<bool> mIsClosed = false;
+
+    DISALLOW_COPY_AND_ASSIGN(CloseHandle);
+};
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace can
+}  // namespace automotive
+}  // namespace hardware
+}  // namespace android