Add Bluetooth Audio AIDL utils

Test: manual
Bug: 203490261
Change-Id: Ia299a61e89273ea1c9d132425598975418f57a03
diff --git a/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h b/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h
new file mode 100644
index 0000000..85fd571
--- /dev/null
+++ b/bluetooth/audio/utils/aidl_session/BluetoothAudioSession.h
@@ -0,0 +1,227 @@
+/*
+ * Copyright (C) 2022 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 <aidl/android/hardware/audio/common/SinkMetadata.h>
+#include <aidl/android/hardware/audio/common/SourceMetadata.h>
+#include <aidl/android/hardware/bluetooth/audio/IBluetoothAudioProvider.h>
+#include <aidl/android/hardware/bluetooth/audio/IBluetoothAudioProviderFactory.h>
+#include <aidl/android/hardware/bluetooth/audio/SessionType.h>
+#include <fmq/AidlMessageQueue.h>
+#include <hardware/audio.h>
+
+#include <mutex>
+#include <unordered_map>
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace bluetooth {
+namespace audio {
+
+using ::aidl::android::hardware::common::fmq::MQDescriptor;
+using ::aidl::android::hardware::common::fmq::SynchronizedReadWrite;
+using ::android::AidlMessageQueue;
+
+using ::aidl::android::hardware::audio::common::SinkMetadata;
+using ::aidl::android::hardware::audio::common::SourceMetadata;
+
+using MQDataType = int8_t;
+using MQDataMode = SynchronizedReadWrite;
+using DataMQ = AidlMessageQueue<MQDataType, MQDataMode>;
+using DataMQDesc =
+    ::aidl::android::hardware::common::fmq::MQDescriptor<MQDataType,
+                                                         MQDataMode>;
+
+static constexpr uint16_t kObserversCookieSize = 0x0010;  // 0x0000 ~ 0x000f
+static constexpr uint16_t kObserversCookieUndefined =
+    (static_cast<uint16_t>(SessionType::UNKNOWN) << 8 & 0xff00);
+inline SessionType ObserversCookieGetSessionType(uint16_t cookie) {
+  return static_cast<SessionType>(cookie >> 8 & 0x00ff);
+}
+inline uint16_t ObserversCookieGetInitValue(SessionType session_type) {
+  return (static_cast<uint16_t>(session_type) << 8 & 0xff00);
+}
+inline uint16_t ObserversCookieGetUpperBound(SessionType session_type) {
+  return (static_cast<uint16_t>(session_type) << 8 & 0xff00) +
+         kObserversCookieSize;
+}
+
+/***
+ * This presents the callbacks of started / suspended and session changed,
+ * and the bluetooth_audio module uses to receive the status notification
+ ***/
+struct PortStatusCallbacks {
+  /***
+   * control_result_cb_ - when the Bluetooth stack reports results of
+   * streamStarted or streamSuspended, the BluetoothAudioProvider will invoke
+   * this callback to report to the bluetooth_audio module.
+   * @param: cookie - indicates which bluetooth_audio output should handle
+   * @param: start_resp - this report is for startStream or not
+   * @param: status - the result of startStream
+   ***/
+  std::function<void(uint16_t cookie, bool start_resp,
+                     BluetoothAudioStatus status)>
+      control_result_cb_;
+  /***
+   * session_changed_cb_ - when the Bluetooth stack start / end session, the
+   * BluetoothAudioProvider will invoke this callback to notify to the
+   * bluetooth_audio module.
+   * @param: cookie - indicates which bluetooth_audio output should handle
+   ***/
+  std::function<void(uint16_t cookie)> session_changed_cb_;
+  /***
+   * audio_configuration_changed_cb_ - when the Bluetooth stack change the audio
+   * configuration, the BluetoothAudioProvider will invoke this callback to
+   * notify to the bluetooth_audio module.
+   * @param: cookie - indicates which bluetooth_audio output should handle
+   ***/
+  std::function<void(uint16_t cookie)> audio_configuration_changed_cb_;
+};
+
+class BluetoothAudioSession {
+ public:
+  BluetoothAudioSession(const SessionType& session_type);
+
+  /***
+   * The function helps to check if this session is ready or not
+   * @return: true if the Bluetooth stack has started the specified session
+   ***/
+  bool IsSessionReady();
+
+  /***
+   * The report function is used to report that the Bluetooth stack has started
+   * this session without any failure, and will invoke session_changed_cb_ to
+   * notify those registered bluetooth_audio outputs
+   ***/
+  void OnSessionStarted(const std::shared_ptr<IBluetoothAudioPort> stack_iface,
+                        const DataMQDesc* mq_desc,
+                        const AudioConfiguration& audio_config);
+
+  /***
+   * The report function is used to report that the Bluetooth stack has ended
+   * the session, and will invoke session_changed_cb_ to notify registered
+   * bluetooth_audio outputs
+   ***/
+  void OnSessionEnded();
+
+  /***
+   * The report function is used to report that the Bluetooth stack has notified
+   * the result of startStream or suspendStream, and will invoke
+   * control_result_cb_ to notify registered bluetooth_audio outputs
+   ***/
+  void ReportControlStatus(bool start_resp, BluetoothAudioStatus status);
+
+  /***
+   * The control function helps the bluetooth_audio module to register
+   * PortStatusCallbacks
+   * @return: cookie - the assigned number to this bluetooth_audio output
+   ***/
+  uint16_t RegisterStatusCback(const PortStatusCallbacks& cbacks);
+
+  /***
+   * The control function helps the bluetooth_audio module to unregister
+   * PortStatusCallbacks
+   * @param: cookie - indicates which bluetooth_audio output is
+   ***/
+  void UnregisterStatusCback(uint16_t cookie);
+
+  /***
+   * The control function is for the bluetooth_audio module to get the current
+   * AudioConfiguration
+   ***/
+  const AudioConfiguration& GetAudioConfig();
+
+  /***
+   * The report function is used to report that the Bluetooth stack has notified
+   * the audio configuration changed, and will invoke
+   * audio_configuration_changed_cb_ to notify registered bluetooth_audio
+   * outputs
+   ***/
+  void ReportAudioConfigChanged(const AudioConfiguration& audio_config);
+
+  /***
+   * Those control functions are for the bluetooth_audio module to start,
+   * suspend, stop stream, to check position, and to update metadata.
+   ***/
+  bool StartStream();
+  bool SuspendStream();
+  void StopStream();
+  bool GetPresentationPosition(PresentationPosition& presentation_position);
+  void UpdateSourceMetadata(const struct source_metadata& source_metadata);
+  void UpdateSinkMetadata(const struct sink_metadata& sink_metadata);
+
+  // The control function writes stream to FMQ
+  size_t OutWritePcmData(const void* buffer, size_t bytes);
+  // The control function read stream from FMQ
+  size_t InReadPcmData(void* buffer, size_t bytes);
+
+  // Return if IBluetoothAudioProviderFactory implementation existed
+  static bool IsAidlAvailable();
+
+  static constexpr PcmConfiguration kInvalidPcmConfiguration = {};
+  // can't be constexpr because of non-literal type
+  static const CodecConfiguration kInvalidCodecConfiguration;
+
+  static AudioConfiguration invalidSoftwareAudioConfiguration;
+  static AudioConfiguration invalidOffloadAudioConfiguration;
+  static AudioConfiguration invalidLeOffloadAudioConfig;
+
+ private:
+  // using recursive_mutex to allow hwbinder to re-enter again.
+  std::recursive_mutex mutex_;
+  SessionType session_type_;
+
+  // audio control path to use for both software and offloading
+  std::shared_ptr<IBluetoothAudioPort> stack_iface_;
+  // audio data path (FMQ) for software encoding
+  std::unique_ptr<DataMQ> data_mq_;
+  // audio data configuration for both software and offloading
+  std::unique_ptr<AudioConfiguration> audio_config_;
+
+  // saving those registered bluetooth_audio's callbacks
+  std::unordered_map<uint16_t, std::shared_ptr<struct PortStatusCallbacks>>
+      observers_;
+
+  bool UpdateDataPath(const DataMQDesc* mq_desc);
+  bool UpdateAudioConfig(const AudioConfiguration& audio_config);
+  // invoking the registered session_changed_cb_
+  void ReportSessionStatus();
+
+  static inline std::atomic<bool> is_aidl_checked = false;
+  static inline std::atomic<bool> is_aidl_available = false;
+  static inline const std::string kDefaultAudioProviderFactoryInterface =
+      std::string() + IBluetoothAudioProviderFactory::descriptor + "/default";
+};
+
+class BluetoothAudioSessionInstance {
+ public:
+  // The API is to fetch the specified session of A2DP / Hearing Aid
+  static std::shared_ptr<BluetoothAudioSession> GetSessionInstance(
+      const SessionType& session_type);
+
+ private:
+  static std::mutex mutex_;
+  static std::unordered_map<SessionType, std::shared_ptr<BluetoothAudioSession>>
+      sessions_map_;
+};
+
+}  // namespace audio
+}  // namespace bluetooth
+}  // namespace hardware
+}  // namespace android
+}  // namespace aidl
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