Moved headers from include/ to appropriate libs

include/camera -> camera/include/camera
include/media/audiohal -> media/libaudiohal/include
include/media/AudioResampler*.h -> media/libaudioprocessing/include
include/media/Audio*.h,IAudio*.h,IEffect*.h,ToneGenerator.h -> media/libaudioclient/include
include/media/EffectsFactoryApi.h -> media/libeffects/include
include/media/stagefright -> media/libstagefright/include
include/media/nbaio -> media/libnbaio/include
include/media/<rest of files> -> media/libmedia/include
include/cpustats -> media/libcpustats/include/cpustats

Added symlinks from old location to new ones

Bug: 33241851

Test: VNDK linked modules will need to add explicit lib dep.
All other modules should compile the same

Change-Id: I0ecf754a2132640ae781a3cc31428fb8c0bd1669
diff --git a/media/libaudiohal/Android.mk b/media/libaudiohal/Android.mk
index 286c6b7..032b3e9 100644
--- a/media/libaudiohal/Android.mk
+++ b/media/libaudiohal/Android.mk
@@ -52,6 +52,10 @@
 
 endif  # USE_LEGACY_LOCAL_AUDIO_HAL
 
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
+
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+
 LOCAL_MODULE := libaudiohal
 
 LOCAL_CFLAGS := -Wall -Werror
diff --git a/media/libaudiohal/include/DeviceHalInterface.h b/media/libaudiohal/include/DeviceHalInterface.h
new file mode 100644
index 0000000..caf01be
--- /dev/null
+++ b/media/libaudiohal/include/DeviceHalInterface.h
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_DEVICE_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_DEVICE_HAL_INTERFACE_H
+
+#include <system/audio.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/String8.h>
+
+namespace android {
+
+class StreamInHalInterface;
+class StreamOutHalInterface;
+
+class DeviceHalInterface : public RefBase
+{
+  public:
+    // Sets the value of 'devices' to a bitmask of 1 or more values of audio_devices_t.
+    virtual status_t getSupportedDevices(uint32_t *devices) = 0;
+
+    // Check to see if the audio hardware interface has been initialized.
+    virtual status_t initCheck() = 0;
+
+    // Set the audio volume of a voice call. Range is between 0.0 and 1.0.
+    virtual status_t setVoiceVolume(float volume) = 0;
+
+    // Set the audio volume for all audio activities other than voice call.
+    virtual status_t setMasterVolume(float volume) = 0;
+
+    // Get the current master volume value for the HAL.
+    virtual status_t getMasterVolume(float *volume) = 0;
+
+    // Called when the audio mode changes.
+    virtual status_t setMode(audio_mode_t mode) = 0;
+
+    // Muting control.
+    virtual status_t setMicMute(bool state) = 0;
+    virtual status_t getMicMute(bool *state) = 0;
+    virtual status_t setMasterMute(bool state) = 0;
+    virtual status_t getMasterMute(bool *state) = 0;
+
+    // Set global audio parameters.
+    virtual status_t setParameters(const String8& kvPairs) = 0;
+
+    // Get global audio parameters.
+    virtual status_t getParameters(const String8& keys, String8 *values) = 0;
+
+    // Returns audio input buffer size according to parameters passed.
+    virtual status_t getInputBufferSize(const struct audio_config *config,
+            size_t *size) = 0;
+
+    // Creates and opens the audio hardware output stream. The stream is closed
+    // by releasing all references to the returned object.
+    virtual status_t openOutputStream(
+            audio_io_handle_t handle,
+            audio_devices_t devices,
+            audio_output_flags_t flags,
+            struct audio_config *config,
+            const char *address,
+            sp<StreamOutHalInterface> *outStream) = 0;
+
+    // Creates and opens the audio hardware input stream. The stream is closed
+    // by releasing all references to the returned object.
+    virtual status_t openInputStream(
+            audio_io_handle_t handle,
+            audio_devices_t devices,
+            struct audio_config *config,
+            audio_input_flags_t flags,
+            const char *address,
+            audio_source_t source,
+            sp<StreamInHalInterface> *inStream) = 0;
+
+    // Returns whether createAudioPatch and releaseAudioPatch operations are supported.
+    virtual status_t supportsAudioPatches(bool *supportsPatches) = 0;
+
+    // Creates an audio patch between several source and sink ports.
+    virtual status_t createAudioPatch(
+            unsigned int num_sources,
+            const struct audio_port_config *sources,
+            unsigned int num_sinks,
+            const struct audio_port_config *sinks,
+            audio_patch_handle_t *patch) = 0;
+
+    // Releases an audio patch.
+    virtual status_t releaseAudioPatch(audio_patch_handle_t patch) = 0;
+
+    // Fills the list of supported attributes for a given audio port.
+    virtual status_t getAudioPort(struct audio_port *port) = 0;
+
+    // Set audio port configuration.
+    virtual status_t setAudioPortConfig(const struct audio_port_config *config) = 0;
+
+    virtual status_t dump(int fd) = 0;
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    DeviceHalInterface() {}
+
+    // The destructor automatically closes the device.
+    virtual ~DeviceHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_DEVICE_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/DevicesFactoryHalInterface.h b/media/libaudiohal/include/DevicesFactoryHalInterface.h
new file mode 100644
index 0000000..14af384
--- /dev/null
+++ b/media/libaudiohal/include/DevicesFactoryHalInterface.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_DEVICES_FACTORY_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_DEVICES_FACTORY_HAL_INTERFACE_H
+
+#include <media/audiohal/DeviceHalInterface.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+namespace android {
+
+class DevicesFactoryHalInterface : public RefBase
+{
+  public:
+    // Opens a device with the specified name. To close the device, it is
+    // necessary to release references to the returned object.
+    virtual status_t openDevice(const char *name, sp<DeviceHalInterface> *device) = 0;
+
+    static sp<DevicesFactoryHalInterface> create();
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    DevicesFactoryHalInterface() {}
+
+    virtual ~DevicesFactoryHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_DEVICES_FACTORY_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/EffectBufferHalInterface.h b/media/libaudiohal/include/EffectBufferHalInterface.h
new file mode 100644
index 0000000..6fa7940
--- /dev/null
+++ b/media/libaudiohal/include/EffectBufferHalInterface.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#ifndef ANDROID_HARDWARE_EFFECT_BUFFER_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_EFFECT_BUFFER_HAL_INTERFACE_H
+
+#include <system/audio_effect.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+namespace android {
+
+// Abstraction for an audio buffer. It may be a "mirror" for
+// a buffer that the effect chain doesn't own, or a buffer owned by
+// the effect chain.
+class EffectBufferHalInterface : public RefBase
+{
+  public:
+    virtual audio_buffer_t* audioBuffer() = 0;
+    virtual void* externalData() const = 0;
+    // To be used when interacting with the code that doesn't know about
+    // "mirrored" buffers.
+    virtual void* ptr() {
+        return externalData() != nullptr ? externalData() : audioBuffer()->raw;
+    }
+
+    virtual void setExternalData(void* external) = 0;
+    virtual void setFrameCount(size_t frameCount) = 0;
+
+    virtual void update() = 0;  // copies data from the external buffer, noop for allocated buffers
+    virtual void commit() = 0;  // copies data to the external buffer, noop for allocated buffers
+    virtual void update(size_t size) = 0;  // copies partial data from external buffer
+    virtual void commit(size_t size) = 0;  // copies partial data to external buffer
+
+    static status_t allocate(size_t size, sp<EffectBufferHalInterface>* buffer);
+    static status_t mirror(void* external, size_t size, sp<EffectBufferHalInterface>* buffer);
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    EffectBufferHalInterface() {}
+
+    virtual ~EffectBufferHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_EFFECT_BUFFER_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/EffectHalInterface.h b/media/libaudiohal/include/EffectHalInterface.h
new file mode 100644
index 0000000..7f9a6fd
--- /dev/null
+++ b/media/libaudiohal/include/EffectHalInterface.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_EFFECT_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_EFFECT_HAL_INTERFACE_H
+
+#include <media/audiohal/EffectBufferHalInterface.h>
+#include <system/audio_effect.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+namespace android {
+
+class EffectHalInterface : public RefBase
+{
+  public:
+    // Set the input buffer.
+    virtual status_t setInBuffer(const sp<EffectBufferHalInterface>& buffer) = 0;
+
+    // Set the output buffer.
+    virtual status_t setOutBuffer(const sp<EffectBufferHalInterface>& buffer) = 0;
+
+    // Effect process function. Takes input samples as specified
+    // in input buffer descriptor and output processed samples as specified
+    // in output buffer descriptor.
+    virtual status_t process() = 0;
+
+    // Process reverse stream function. This function is used to pass
+    // a reference stream to the effect engine.
+    virtual status_t processReverse() = 0;
+
+    // Send a command and receive a response to/from effect engine.
+    virtual status_t command(uint32_t cmdCode, uint32_t cmdSize, void *pCmdData,
+            uint32_t *replySize, void *pReplyData) = 0;
+
+    // Returns the effect descriptor.
+    virtual status_t getDescriptor(effect_descriptor_t *pDescriptor) = 0;
+
+    // Free resources on the remote side.
+    virtual status_t close() = 0;
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    EffectHalInterface() {}
+
+    // The destructor automatically releases the effect.
+    virtual ~EffectHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_EFFECT_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/EffectsFactoryHalInterface.h b/media/libaudiohal/include/EffectsFactoryHalInterface.h
new file mode 100644
index 0000000..a616e86
--- /dev/null
+++ b/media/libaudiohal/include/EffectsFactoryHalInterface.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_INTERFACE_H
+
+#include <media/audiohal/EffectHalInterface.h>
+#include <system/audio_effect.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+
+namespace android {
+
+class EffectsFactoryHalInterface : public RefBase
+{
+  public:
+    // Returns the number of different effects in all loaded libraries.
+    virtual status_t queryNumberEffects(uint32_t *pNumEffects) = 0;
+
+    // Returns a descriptor of the next available effect.
+    virtual status_t getDescriptor(uint32_t index,
+            effect_descriptor_t *pDescriptor) = 0;
+
+    virtual status_t getDescriptor(const effect_uuid_t *pEffectUuid,
+            effect_descriptor_t *pDescriptor) = 0;
+
+    // Creates an effect engine of the specified type.
+    // To release the effect engine, it is necessary to release references
+    // to the returned effect object.
+    virtual status_t createEffect(const effect_uuid_t *pEffectUuid,
+            int32_t sessionId, int32_t ioId,
+            sp<EffectHalInterface> *effect) = 0;
+
+    virtual status_t dumpEffects(int fd) = 0;
+
+    static sp<EffectsFactoryHalInterface> create();
+
+    // Helper function to compare effect uuid to EFFECT_UUID_NULL.
+    static bool isNullUuid(const effect_uuid_t *pEffectUuid);
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    EffectsFactoryHalInterface() {}
+
+    virtual ~EffectsFactoryHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/StreamHalInterface.h b/media/libaudiohal/include/StreamHalInterface.h
new file mode 100644
index 0000000..7419c34
--- /dev/null
+++ b/media/libaudiohal/include/StreamHalInterface.h
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_STREAM_HAL_INTERFACE_H
+#define ANDROID_HARDWARE_STREAM_HAL_INTERFACE_H
+
+#include <media/audiohal/EffectHalInterface.h>
+#include <system/audio.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/String8.h>
+
+namespace android {
+
+class StreamHalInterface : public virtual RefBase
+{
+  public:
+    // Return the sampling rate in Hz - eg. 44100.
+    virtual status_t getSampleRate(uint32_t *rate) = 0;
+
+    // Return size of input/output buffer in bytes for this stream - eg. 4800.
+    virtual status_t getBufferSize(size_t *size) = 0;
+
+    // Return the channel mask.
+    virtual status_t getChannelMask(audio_channel_mask_t *mask) = 0;
+
+    // Return the audio format - e.g. AUDIO_FORMAT_PCM_16_BIT.
+    virtual status_t getFormat(audio_format_t *format) = 0;
+
+    // Convenience method.
+    virtual status_t getAudioProperties(
+            uint32_t *sampleRate, audio_channel_mask_t *mask, audio_format_t *format) = 0;
+
+    // Set audio stream parameters.
+    virtual status_t setParameters(const String8& kvPairs) = 0;
+
+    // Get audio stream parameters.
+    virtual status_t getParameters(const String8& keys, String8 *values) = 0;
+
+    // Return the frame size (number of bytes per sample) of a stream.
+    virtual status_t getFrameSize(size_t *size) = 0;
+
+    // Add or remove the effect on the stream.
+    virtual status_t addEffect(sp<EffectHalInterface> effect) = 0;
+    virtual status_t removeEffect(sp<EffectHalInterface> effect) = 0;
+
+    // Put the audio hardware input/output into standby mode.
+    virtual status_t standby() = 0;
+
+    virtual status_t dump(int fd) = 0;
+
+    // Start a stream operating in mmap mode.
+    virtual status_t start() = 0;
+
+    // Stop a stream operating in mmap mode.
+    virtual status_t stop() = 0;
+
+    // Retrieve information on the data buffer in mmap mode.
+    virtual status_t createMmapBuffer(int32_t minSizeFrames,
+                                      struct audio_mmap_buffer_info *info) = 0;
+
+    // Get current read/write position in the mmap buffer
+    virtual status_t getMmapPosition(struct audio_mmap_position *position) = 0;
+
+    // Set the priority of the thread that interacts with the HAL
+    // (must match the priority of the audioflinger's thread that calls 'read' / 'write')
+    virtual status_t setHalThreadPriority(int priority) = 0;
+
+  protected:
+    // Subclasses can not be constructed directly by clients.
+    StreamHalInterface() {}
+
+    // The destructor automatically closes the stream.
+    virtual ~StreamHalInterface() {}
+};
+
+class StreamOutHalInterfaceCallback : public virtual RefBase {
+  public:
+    virtual void onWriteReady() {}
+    virtual void onDrainReady() {}
+    virtual void onError() {}
+
+  protected:
+    StreamOutHalInterfaceCallback() {}
+    virtual ~StreamOutHalInterfaceCallback() {}
+};
+
+class StreamOutHalInterface : public virtual StreamHalInterface {
+  public:
+    // Return the audio hardware driver estimated latency in milliseconds.
+    virtual status_t getLatency(uint32_t *latency) = 0;
+
+    // Use this method in situations where audio mixing is done in the hardware.
+    virtual status_t setVolume(float left, float right) = 0;
+
+    // Write audio buffer to driver.
+    virtual status_t write(const void *buffer, size_t bytes, size_t *written) = 0;
+
+    // Return the number of audio frames written by the audio dsp to DAC since
+    // the output has exited standby.
+    virtual status_t getRenderPosition(uint32_t *dspFrames) = 0;
+
+    // Get the local time at which the next write to the audio driver will be presented.
+    virtual status_t getNextWriteTimestamp(int64_t *timestamp) = 0;
+
+    // Set the callback for notifying completion of non-blocking write and drain.
+    // The callback must be owned by someone else. The output stream does not own it
+    // to avoid strong pointer loops.
+    virtual status_t setCallback(wp<StreamOutHalInterfaceCallback> callback) = 0;
+
+    // Returns whether pause and resume operations are supported.
+    virtual status_t supportsPauseAndResume(bool *supportsPause, bool *supportsResume) = 0;
+
+    // Notifies to the audio driver to resume playback following a pause.
+    virtual status_t pause() = 0;
+
+    // Notifies to the audio driver to resume playback following a pause.
+    virtual status_t resume() = 0;
+
+    // Returns whether drain operation is supported.
+    virtual status_t supportsDrain(bool *supportsDrain) = 0;
+
+    // Requests notification when data buffered by the driver/hardware has been played.
+    virtual status_t drain(bool earlyNotify) = 0;
+
+    // Notifies to the audio driver to flush the queued data.
+    virtual status_t flush() = 0;
+
+    // Return a recent count of the number of audio frames presented to an external observer.
+    virtual status_t getPresentationPosition(uint64_t *frames, struct timespec *timestamp) = 0;
+
+  protected:
+    virtual ~StreamOutHalInterface() {}
+};
+
+class StreamInHalInterface : public virtual StreamHalInterface {
+  public:
+    // Set the input gain for the audio driver.
+    virtual status_t setGain(float gain) = 0;
+
+    // Read audio buffer in from driver.
+    virtual status_t read(void *buffer, size_t bytes, size_t *read) = 0;
+
+    // Return the amount of input frames lost in the audio driver.
+    virtual status_t getInputFramesLost(uint32_t *framesLost) = 0;
+
+    // Return a recent count of the number of audio frames received and
+    // the clock time associated with that frame count.
+    virtual status_t getCapturePosition(int64_t *frames, int64_t *time) = 0;
+
+  protected:
+    virtual ~StreamInHalInterface() {}
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_STREAM_HAL_INTERFACE_H
diff --git a/media/libaudiohal/include/hidl/HalDeathHandler.h b/media/libaudiohal/include/hidl/HalDeathHandler.h
new file mode 100644
index 0000000..c9b7084
--- /dev/null
+++ b/media/libaudiohal/include/hidl/HalDeathHandler.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#ifndef ANDROID_HARDWARE_HIDL_HAL_DEATH_HANDLER_H
+#define ANDROID_HARDWARE_HIDL_HAL_DEATH_HANDLER_H
+
+#include <functional>
+#include <mutex>
+#include <unordered_map>
+
+#include <hidl/HidlSupport.h>
+#include <utils/Singleton.h>
+
+using android::hardware::hidl_death_recipient;
+using android::hidl::base::V1_0::IBase;
+
+namespace android {
+
+class HalDeathHandler : public hidl_death_recipient, private Singleton<HalDeathHandler> {
+  public:
+    typedef std::function<void()> AtExitHandler;
+
+    // Note that the exit handler gets called using a thread from
+    // RPC threadpool, thus it needs to be thread-safe.
+    void registerAtExitHandler(void* cookie, AtExitHandler handler);
+    void unregisterAtExitHandler(void* cookie);
+
+    // hidl_death_recipient
+    virtual void serviceDied(uint64_t cookie, const wp<IBase>& who);
+
+    // Used both for (un)registering handlers, and for passing to
+    // '(un)linkToDeath'.
+    static sp<HalDeathHandler> getInstance();
+
+  private:
+    friend class Singleton<HalDeathHandler>;
+    typedef std::unordered_map<void*, AtExitHandler> Handlers;
+
+    HalDeathHandler();
+    virtual ~HalDeathHandler();
+
+    sp<HalDeathHandler> mSelf;  // Allows the singleton instance to live forever.
+    std::mutex mHandlersLock;
+    Handlers mHandlers;
+};
+
+}  // namespace android
+
+#endif // ANDROID_HARDWARE_HIDL_HAL_DEATH_HANDLER_H