services/audiopolicy/engine/interface/EngineInterface.h - android_frameworks_av - Gitiles

 /*
  * Copyright (C) 2015 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 <utility>

 #include <AudioPolicyManagerObserver.h>
 #include <media/AudioProductStrategy.h>
 #include <media/AudioVolumeGroup.h>
 #include <IVolumeCurves.h>
 #include <policy.h>
 #include <Volume.h>
 #include <HwModule.h>
 #include <DeviceDescriptor.h>
 #include <system/audio.h>
 #include <system/audio_policy.h>
 #include <utils/Errors.h>
 #include <utils/Vector.h>

 namespace android {

 using DeviceStrategyMap = std::map<product_strategy_t, DeviceVector>;
 using StrategyVector = std::vector<product_strategy_t>;
 using VolumeGroupVector = std::vector<volume_group_t>;
 using CapturePresetDevicesRoleMap =
         std::map<std::pair<audio_source_t, device_role_t>, AudioDeviceTypeAddrVector>;

 /**
  * This interface is dedicated to the policy manager that a Policy Engine shall implement.
  */
 class EngineInterface
 {
 public:
     /**
      * Checks if the engine was correctly initialized.
      *
      * @return NO_ERROR if initialization has been done correctly, error code otherwise..
      */
     virtual status_t initCheck() = 0;

     /**
      * Sets the Manager observer that allows the engine to retrieve information on collection
      * of devices, streams, HwModules, ...
      *
      * @param[in] observer handle on the manager.
      */
     virtual void setObserver(AudioPolicyManagerObserver *observer) = 0;

     /**
      * Set the Telephony Mode.
      *
      * @param[in] mode: Android Phone state (normal, ringtone, csv, in communication)
      *
      * @return NO_ERROR if Telephony Mode set correctly, error code otherwise.
      */
     virtual status_t setPhoneState(audio_mode_t mode) = 0;

     /**
      * Get the telephony Mode
      *
      * @return the current telephony mode
      */
     virtual audio_mode_t getPhoneState() const = 0;

     /**
      * Set Force Use config for a given usage.
      *
      * @param[in] usage for which a configuration shall be forced.
      * @param[in] config wished to be forced for the given usage.
      *
      * @return NO_ERROR if the Force Use config was set correctly, error code otherwise (e.g. config
      * not allowed a given usage...)
      */
     virtual status_t setForceUse(audio_policy_force_use_t usage,
                                  audio_policy_forced_cfg_t config) = 0;

     /**
      * Get Force Use config for a given usage.
      *
      * @param[in] usage for which a configuration shall be forced.
      *
      * @return config wished to be forced for the given usage.
      */
     virtual audio_policy_forced_cfg_t getForceUse(audio_policy_force_use_t usage) const = 0;

     /**
      * Set the connection state of device(s).
      *
      * @param[in] devDesc for which the state has changed.
      * @param[in] state of availability of this(these) device(s).
      *
      * @return NO_ERROR if devices criterion updated correctly, error code otherwise.
      */
     virtual status_t setDeviceConnectionState(const android::sp<android::DeviceDescriptor> devDesc,
                                               audio_policy_dev_state_t state) = 0;

     /**
      * Get the strategy selected for a given audio attributes.
      *
      * @param[in] audio attributes to get the selected @product_strategy_t followed by.
      * @param fallbackOnDefault if true, will return the fallback strategy if the attributes
      * are not explicitly assigned to a given strategy.
      * @return @product_strategy_t to be followed.
      */
     virtual product_strategy_t getProductStrategyForAttributes(
             const audio_attributes_t &attr, bool fallbackOnDefault = true) const = 0;

     /**
      * @brief getOutputDevicesForAttributes retrieves the devices to be used for given
      * audio attributes.
      * @param attributes of the output requesting Device(s) selection
      * @param preferedDevice valid reference if a prefered device is requested, nullptr otherwise.
      * @param fromCache if true, the device is returned from internal cache,
      *                  otherwise it is determined by current state (device connected,phone state,
      *                  force use, a2dp output...)
      * @return vector of selected device descriptors.
      *         Appropriate device for streams handled by the specified audio attributes according
      *         to current phone state, forced states, connected devices...
      *         if fromCache is true, the device is returned from internal cache,
      *         otherwise it is determined by current state (device connected,phone state, force use,
      *         a2dp output...)
      * This allows to:
      *      1 speed up process when the state is stable (when starting or stopping an output)
      *      2 access to either current device selection (fromCache == true) or
      *      "future" device selection (fromCache == false) when called from a context
      *      where conditions are changing (setDeviceConnectionState(), setPhoneState()...) AND
      *      before manager updates its outputs.
      */
     virtual DeviceVector getOutputDevicesForAttributes(
             const audio_attributes_t &attributes,
             const sp<DeviceDescriptor> &preferedDevice = nullptr,
             bool fromCache = false) const = 0;

     /**
      * @brief getOutputDevicesForStream Legacy function retrieving devices from a stream type.
      * @param stream type of the output requesting Device(s) selection
      * @param fromCache if true, the device is returned from internal cache,
      *                  otherwise it is determined by current state (device connected,phone state,
      *                  force use, a2dp output...)
      * @return appropriate device for streams handled by the specified audio attributes according
      *         to current phone state, forced states, connected devices...
      *         if fromCache is true, the device is returned from internal cache,
      *         otherwise it is determined by current state (device connected,phone state, force use,
      *         a2dp output...)
      * This allows to:
      *      1 speed up process when the state is stable (when starting or stopping an output)
      *      2 access to either current device selection (fromCache == true) or
      *      "future" device selection (fromCache == false) when called from a context
      *      where conditions are changing (setDeviceConnectionState(), setPhoneState()...) AND
      *      before manager updates its outputs.
      */
     virtual DeviceVector getOutputDevicesForStream(audio_stream_type_t stream,
                                                    bool fromCache = false) const = 0;

     /**
      * Get the input device selected for given audio attributes.
      *
      * @param[in] attr audio attributes to consider
      * @param[out] mix to be used if a mix has been installed for the given audio attributes.
      * @return selected input device for the audio attributes, may be null if error.
      */
     virtual sp<DeviceDescriptor> getInputDeviceForAttributes(
             const audio_attributes_t &attr,
             uid_t uid = 0,
             audio_session_t session = AUDIO_SESSION_NONE,
             sp<AudioPolicyMix> *mix = nullptr) const = 0;

     /**
      * Get the legacy stream type for a given audio attributes.
      *
      * @param[in] audio attributes to get the associated audio_stream_type_t.
      *
      * @return audio_stream_type_t associated to the attributes.
      */
     virtual audio_stream_type_t getStreamTypeForAttributes(
             const audio_attributes_t &attr) const = 0;

     /**
      * @brief getAttributesForStream get the audio attributes from legacy stream type
      * Attributes returned might only be used to check upon routing decision, not volume decisions.
      * @param stream to consider
      * @return audio attributes matching the legacy stream type
      */
     virtual audio_attributes_t getAttributesForStreamType(audio_stream_type_t stream) const = 0;

     /**
      * @brief getStreamTypesForProductStrategy retrieves the list of legacy stream type following
      * the given product strategy
      * @param ps product strategy to consider
      * @return associated legacy Stream Types vector of the given product strategy
      */
     virtual StreamTypeVector getStreamTypesForProductStrategy(product_strategy_t ps) const = 0;

     /**
      * @brief getAllAttributesForProductStrategy retrieves all the attributes following the given
      * product strategy. Any attributes that "matches" with this one will follow the product
      * strategy.
      * "matching" means the usage shall match if reference attributes has a defined usage, AND
      * content type shall match if reference attributes has a defined content type AND
      * flags shall match if reference attributes has defined flags AND
      * tags shall match if reference attributes has defined tags.
      * @param ps product strategy to consider
      * @return vector of product strategy ids, empty if unknown strategy.
      */
     virtual AttributesVector getAllAttributesForProductStrategy(product_strategy_t ps) const = 0;

     /**
      * @brief getOrderedAudioProductStrategies
      * @return priority ordered product strategies to help the AudioPolicyManager evaluating the
      * device selection per output according to the prioritized strategies.
      */
     virtual StrategyVector getOrderedProductStrategies() const = 0;

     /**
      * @brief updateDeviceSelectionCache. Device selection for AudioAttribute / Streams is cached
      * in the engine in order to speed up process when the audio system is stable.
      * When a device is connected, the android mode is changed, engine is notified and can update
      * the cache.
      * When starting / stopping an output with a stream that can affect notification, the engine
      * needs to update the cache upon this function call.
      */
     virtual void updateDeviceSelectionCache() = 0;

     /**
      * @brief listAudioProductStrategies. Introspection API to retrieve a collection of
      * AudioProductStrategyVector that allows to build AudioAttributes according to a
      * product_strategy which is just an index. It has also a human readable name to help the
      * Car/Oem/AudioManager identiying the use case.
      * @param strategies collection.
      * @return OK if the list has been retrieved, error code otherwise
      */
     virtual status_t listAudioProductStrategies(AudioProductStrategyVector &strategies) const = 0;

     /**
      * @brief getVolumeCurvesForAttributes retrieves the Volume Curves interface for the
      *        requested Audio Attributes.
      * @param attr to be considered
      * @return IVolumeCurves interface pointer if found, nullptr otherwise
      */
     virtual IVolumeCurves *getVolumeCurvesForAttributes(const audio_attributes_t &attr) const = 0;

     /**
      * @brief getVolumeCurvesForStreamType retrieves the Volume Curves interface for the stream
      * @param stream to be considered
      * @return IVolumeCurves interface pointer if found, nullptr otherwise
      */
     virtual IVolumeCurves *getVolumeCurvesForStreamType(audio_stream_type_t stream) const = 0;

     /**
      * @brief getVolumeCurvesForVolumeGroup retrieves the Volume Curves interface for volume group
      * @param group to be considered
      * @return IVolumeCurves interface pointer if found, nullptr otherwise
      */
     virtual IVolumeCurves *getVolumeCurvesForVolumeGroup(volume_group_t group) const = 0;

     /**
      * @brief getVolumeGroups retrieves the collection of volume groups.
      * @return vector of volume groups
      */
     virtual VolumeGroupVector getVolumeGroups() const = 0;

     /**
      * @brief getVolumeGroupForAttributes gets the appropriate volume group to be used for a given
      * Audio Attributes.
      * @param attr to be considered
      * @param fallbackOnDefault if true, will return the fallback volume group if the attributes
      * are not associated to any volume group.
      * @return volume group associated to the given audio attributes, default group if none
      * applicable, VOLUME_GROUP_NONE if no default group defined.
      */
     virtual volume_group_t getVolumeGroupForAttributes(
             const audio_attributes_t &attr, bool fallbackOnDefault = true) const = 0;

     /**
      * @brief getVolumeGroupForStreamType gets the appropriate volume group to be used for a given
      * legacy stream type
      * @param stream type to be considered
      * @param fallbackOnDefault if true, will return the fallback volume group if the stream type
      * is not associated to any volume group.
      * @return volume group associated to the given stream type, default group if none applicable,
      * VOLUME_GROUP_NONE if no default group defined.
      */
     virtual volume_group_t getVolumeGroupForStreamType(
             audio_stream_type_t stream, bool fallbackOnDefault = true) const = 0;

     /**
      * @brief listAudioVolumeGroups introspection API to get the Audio Volume Groups, aka
      * former stream aliases in Audio Service, defining volume curves attached to one or more
      * Audio Attributes.
      * @param groups
      * @return NO_ERROR if the volume groups were retrieved successfully, error code otherwise
      */
     virtual status_t listAudioVolumeGroups(AudioVolumeGroupVector &groups) const = 0;

     /**
      * @brief setDevicesRoleForStrategy sets devices role for a strategy when available. To remove
      * devices role, removeDevicesRoleForStrategy must be called. When devices role is set
      * successfully, previously set devices for the same role and strategy will be removed.
      * @param strategy the audio strategy whose routing will be affected
      * @param role the role of the devices for the strategy. All device roles are defined at
      *             system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
      *             for setting.
      * @param devices the audio devices to be set
      * @return BAD_VALUE if the strategy or role is invalid,
      *     or NO_ERROR if the role of the devices for strategy was set
      */
     virtual status_t setDevicesRoleForStrategy(product_strategy_t strategy, device_role_t role,
             const AudioDeviceTypeAddrVector &devices) = 0;

     /**
      * @brief removeDevicesRoleForStrategy removes the role of device(s) previously set
      * for the given strategy
      * @param strategy the audio strategy whose routing will be affected
      * @param role the role of the devices for strategy
      * @param devices the audio devices to be removed
      * @return BAD_VALUE if the strategy or role is invalid,
      *     or NO_ERROR if the devices for this role was removed
      */
     virtual status_t removeDevicesRoleForStrategy(product_strategy_t strategy, device_role_t role,
             const AudioDeviceTypeAddrVector &devices) = 0;

     /**
      * @brief clearDevicesRoleForStrategy removes the role of all devices previously set
      * for the given strategy
      * @param strategy the audio strategy whose routing will be affected
      * @param role the role of the devices for strategy
      * @return BAD_VALUE if the strategy or role is invalid,
      *     or NO_ERROR if the devices for this role was removed
      */
     virtual status_t clearDevicesRoleForStrategy(product_strategy_t strategy,
             device_role_t role) = 0;

     /**
      * @brief getDevicesForRoleAndStrategy queries which devices have the specified role for the
      * specified strategy
      * @param strategy the strategy to query
      * @param role the role of the devices to query
      * @param devices returns list of devices with matching role for the specified strategy.
      *                DEVICE_ROLE_NONE is invalid as input.
      * @return BAD_VALUE if the strategy or role is invalid,
      *     or NAME_NOT_FOUND if no device for the role and strategy was set
      *     or NO_ERROR if the devices parameter contains a list of devices
      */
     virtual status_t getDevicesForRoleAndStrategy(product_strategy_t strategy, device_role_t role,
             AudioDeviceTypeAddrVector &devices) const = 0;

     /**
      * @brief setDevicesRoleForCapturePreset sets devices role for a capture preset when available.
      * To remove devices role, removeDevicesRoleForCapturePreset must be called. Calling
      * clearDevicesRoleForCapturePreset will remove all devices as role. When devices role is set
      * successfully, previously set devices for the same role and capture preset will be removed.
      * @param audioSource the audio capture preset whose routing will be affected
      * @param role the role of the devices for the capture preset. All device roles are defined at
      *             system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
      *             for setting.
      * @param devices the audio devices to be set
      * @return BAD_VALUE if the capture preset or role is invalid,
      *     or NO_ERROR if the role of the devices for capture preset was set
      */
     virtual status_t setDevicesRoleForCapturePreset(audio_source_t audioSource, device_role_t role,
             const AudioDeviceTypeAddrVector &devices) = 0;

     /**
      * @brief addDevicesRoleForCapturePreset adds devices role for a capture preset when available.
      * To remove devices role, removeDevicesRoleForCapturePreset must be called. Calling
      * clearDevicesRoleForCapturePreset will remove all devices as role.
      * @param audioSource the audio capture preset whose routing will be affected
      * @param role the role of the devices for the capture preset. All device roles are defined at
      *             system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
      *             for setting.
      * @param devices the audio devices to be added
      * @return BAD_VALUE if the capture preset or role is invalid,
      *     or NO_ERROR if the role of the devices for capture preset was added
      */
     virtual status_t addDevicesRoleForCapturePreset(audio_source_t audioSource, device_role_t role,
             const AudioDeviceTypeAddrVector &devices) = 0;

     /**
      * @brief removeDevicesRoleForCapturePreset removes the role of device(s) previously set
      * for the given capture preset
      * @param audioSource the audio capture preset whose routing will be affected
      * @param role the role of the devices for the capture preset
      * @param devices the devices to be removed
      * @return BAD_VALUE if 1) the capture preset is invalid, 2) role is invalid or 3) the list of
      *     devices to be removed are not all present as role for a capture preset
      *     or NO_ERROR if the devices for this role was removed
      */
     virtual status_t removeDevicesRoleForCapturePreset(audio_source_t audioSource,
             device_role_t role, const AudioDeviceTypeAddrVector& devices) = 0;

     /**
      * @brief clearDevicesRoleForCapturePreset removes the role of all device(s) previously set
      * for the given capture preset
      * @param audioSource the audio capture preset whose routing will be affected
      * @param role the role of the devices for the capture preset
      * @return BAD_VALUE if the capture preset or role is invalid,
      *     or NO_ERROR if the devices for this role was removed
      */
     virtual status_t clearDevicesRoleForCapturePreset(audio_source_t audioSource,
             device_role_t role);

     /**
      * @brief getDevicesForRoleAndCapturePreset queries which devices have the specified role for
      * the specified capture preset
      * @param audioSource the capture preset to query
      * @param role the role of the devices to query
      * @param devices returns list of devices with matching role for the specified capture preset.
      *                DEVICE_ROLE_NONE is invalid as input.
      * @return BAD_VALUE if the capture preset or role is invalid,
      *     or NAME_NOT_FOUND if no device for the role and capture preset was set
      *     or NO_ERROR if the devices parameter contains a list of devices
      */
     virtual status_t getDevicesForRoleAndCapturePreset(audio_source_t audioSource,
             device_role_t role, AudioDeviceTypeAddrVector &devices) const = 0;

     /**
      * @brief getActiveMediaDevices returns which devices will most likely to be used for media
      * @param availableDevices all available devices
      * @return collection of active devices
      */
     virtual DeviceVector getActiveMediaDevices(const DeviceVector& availableDevices) const = 0;

     virtual void dump(String8 *dst) const = 0;

 protected:
     virtual ~EngineInterface() {}
 };

 __attribute__((visibility("default")))
 extern "C" EngineInterface* createEngineInstance();

 __attribute__((visibility("default")))
 extern "C" void destroyEngineInstance(EngineInterface *engine);

 } // namespace android
	/*
	* Copyright (C) 2015 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 <utility>

	#include <AudioPolicyManagerObserver.h>
	#include <media/AudioProductStrategy.h>
	#include <media/AudioVolumeGroup.h>
	#include <IVolumeCurves.h>
	#include <policy.h>
	#include <Volume.h>
	#include <HwModule.h>
	#include <DeviceDescriptor.h>
	#include <system/audio.h>
	#include <system/audio_policy.h>
	#include <utils/Errors.h>
	#include <utils/Vector.h>

	namespace android {

	using DeviceStrategyMap = std::map<product_strategy_t, DeviceVector>;
	using StrategyVector = std::vector<product_strategy_t>;
	using VolumeGroupVector = std::vector<volume_group_t>;
	using CapturePresetDevicesRoleMap =
	std::map<std::pair<audio_source_t, device_role_t>, AudioDeviceTypeAddrVector>;

	/**
	* This interface is dedicated to the policy manager that a Policy Engine shall implement.
	*/
	class EngineInterface
	{
	public:
	/**
	* Checks if the engine was correctly initialized.
	*
	* @return NO_ERROR if initialization has been done correctly, error code otherwise..
	*/
	virtual status_t initCheck() = 0;

	/**
	* Sets the Manager observer that allows the engine to retrieve information on collection
	* of devices, streams, HwModules, ...
	*
	* @param[in] observer handle on the manager.
	*/
	virtual void setObserver(AudioPolicyManagerObserver *observer) = 0;

	/**
	* Set the Telephony Mode.
	*
	* @param[in] mode: Android Phone state (normal, ringtone, csv, in communication)
	*
	* @return NO_ERROR if Telephony Mode set correctly, error code otherwise.
	*/
	virtual status_t setPhoneState(audio_mode_t mode) = 0;

	/**
	* Get the telephony Mode
	*
	* @return the current telephony mode
	*/
	virtual audio_mode_t getPhoneState() const = 0;

	/**
	* Set Force Use config for a given usage.
	*
	* @param[in] usage for which a configuration shall be forced.
	* @param[in] config wished to be forced for the given usage.
	*
	* @return NO_ERROR if the Force Use config was set correctly, error code otherwise (e.g. config
	* not allowed a given usage...)
	*/
	virtual status_t setForceUse(audio_policy_force_use_t usage,
	audio_policy_forced_cfg_t config) = 0;

	/**
	* Get Force Use config for a given usage.
	*
	* @param[in] usage for which a configuration shall be forced.
	*
	* @return config wished to be forced for the given usage.
	*/
	virtual audio_policy_forced_cfg_t getForceUse(audio_policy_force_use_t usage) const = 0;

	/**
	* Set the connection state of device(s).
	*
	* @param[in] devDesc for which the state has changed.
	* @param[in] state of availability of this(these) device(s).
	*
	* @return NO_ERROR if devices criterion updated correctly, error code otherwise.
	*/
	virtual status_t setDeviceConnectionState(const android::sp<android::DeviceDescriptor> devDesc,
	audio_policy_dev_state_t state) = 0;

	/**
	* Get the strategy selected for a given audio attributes.
	*
	* @param[in] audio attributes to get the selected @product_strategy_t followed by.
	* @param fallbackOnDefault if true, will return the fallback strategy if the attributes
	* are not explicitly assigned to a given strategy.
	* @return @product_strategy_t to be followed.
	*/
	virtual product_strategy_t getProductStrategyForAttributes(
	const audio_attributes_t &attr, bool fallbackOnDefault = true) const = 0;

	/**
	* @brief getOutputDevicesForAttributes retrieves the devices to be used for given
	* audio attributes.
	* @param attributes of the output requesting Device(s) selection
	* @param preferedDevice valid reference if a prefered device is requested, nullptr otherwise.
	* @param fromCache if true, the device is returned from internal cache,
	* otherwise it is determined by current state (device connected,phone state,
	* force use, a2dp output...)
	* @return vector of selected device descriptors.
	* Appropriate device for streams handled by the specified audio attributes according
	* to current phone state, forced states, connected devices...
	* if fromCache is true, the device is returned from internal cache,
	* otherwise it is determined by current state (device connected,phone state, force use,
	* a2dp output...)
	* This allows to:
	* 1 speed up process when the state is stable (when starting or stopping an output)
	* 2 access to either current device selection (fromCache == true) or
	* "future" device selection (fromCache == false) when called from a context
	* where conditions are changing (setDeviceConnectionState(), setPhoneState()...) AND
	* before manager updates its outputs.
	*/
	virtual DeviceVector getOutputDevicesForAttributes(
	const audio_attributes_t &attributes,
	const sp<DeviceDescriptor> &preferedDevice = nullptr,
	bool fromCache = false) const = 0;

	/**
	* @brief getOutputDevicesForStream Legacy function retrieving devices from a stream type.
	* @param stream type of the output requesting Device(s) selection
	* @param fromCache if true, the device is returned from internal cache,
	* otherwise it is determined by current state (device connected,phone state,
	* force use, a2dp output...)
	* @return appropriate device for streams handled by the specified audio attributes according
	* to current phone state, forced states, connected devices...
	* if fromCache is true, the device is returned from internal cache,
	* otherwise it is determined by current state (device connected,phone state, force use,
	* a2dp output...)
	* This allows to:
	* 1 speed up process when the state is stable (when starting or stopping an output)
	* 2 access to either current device selection (fromCache == true) or
	* "future" device selection (fromCache == false) when called from a context
	* where conditions are changing (setDeviceConnectionState(), setPhoneState()...) AND
	* before manager updates its outputs.
	*/
	virtual DeviceVector getOutputDevicesForStream(audio_stream_type_t stream,
	bool fromCache = false) const = 0;

	/**
	* Get the input device selected for given audio attributes.
	*
	* @param[in] attr audio attributes to consider
	* @param[out] mix to be used if a mix has been installed for the given audio attributes.
	* @return selected input device for the audio attributes, may be null if error.
	*/
	virtual sp<DeviceDescriptor> getInputDeviceForAttributes(
	const audio_attributes_t &attr,
	uid_t uid = 0,
	audio_session_t session = AUDIO_SESSION_NONE,
	sp<AudioPolicyMix> *mix = nullptr) const = 0;

	/**
	* Get the legacy stream type for a given audio attributes.
	*
	* @param[in] audio attributes to get the associated audio_stream_type_t.
	*
	* @return audio_stream_type_t associated to the attributes.
	*/
	virtual audio_stream_type_t getStreamTypeForAttributes(
	const audio_attributes_t &attr) const = 0;

	/**
	* @brief getAttributesForStream get the audio attributes from legacy stream type
	* Attributes returned might only be used to check upon routing decision, not volume decisions.
	* @param stream to consider
	* @return audio attributes matching the legacy stream type
	*/
	virtual audio_attributes_t getAttributesForStreamType(audio_stream_type_t stream) const = 0;

	/**
	* @brief getStreamTypesForProductStrategy retrieves the list of legacy stream type following
	* the given product strategy
	* @param ps product strategy to consider
	* @return associated legacy Stream Types vector of the given product strategy
	*/
	virtual StreamTypeVector getStreamTypesForProductStrategy(product_strategy_t ps) const = 0;

	/**
	* @brief getAllAttributesForProductStrategy retrieves all the attributes following the given
	* product strategy. Any attributes that "matches" with this one will follow the product
	* strategy.
	* "matching" means the usage shall match if reference attributes has a defined usage, AND
	* content type shall match if reference attributes has a defined content type AND
	* flags shall match if reference attributes has defined flags AND
	* tags shall match if reference attributes has defined tags.
	* @param ps product strategy to consider
	* @return vector of product strategy ids, empty if unknown strategy.
	*/
	virtual AttributesVector getAllAttributesForProductStrategy(product_strategy_t ps) const = 0;

	/**
	* @brief getOrderedAudioProductStrategies
	* @return priority ordered product strategies to help the AudioPolicyManager evaluating the
	* device selection per output according to the prioritized strategies.
	*/
	virtual StrategyVector getOrderedProductStrategies() const = 0;

	/**
	* @brief updateDeviceSelectionCache. Device selection for AudioAttribute / Streams is cached
	* in the engine in order to speed up process when the audio system is stable.
	* When a device is connected, the android mode is changed, engine is notified and can update
	* the cache.
	* When starting / stopping an output with a stream that can affect notification, the engine
	* needs to update the cache upon this function call.
	*/
	virtual void updateDeviceSelectionCache() = 0;

	/**
	* @brief listAudioProductStrategies. Introspection API to retrieve a collection of
	* AudioProductStrategyVector that allows to build AudioAttributes according to a
	* product_strategy which is just an index. It has also a human readable name to help the
	* Car/Oem/AudioManager identiying the use case.
	* @param strategies collection.
	* @return OK if the list has been retrieved, error code otherwise
	*/
	virtual status_t listAudioProductStrategies(AudioProductStrategyVector &strategies) const = 0;

	/**
	* @brief getVolumeCurvesForAttributes retrieves the Volume Curves interface for the
	* requested Audio Attributes.
	* @param attr to be considered
	* @return IVolumeCurves interface pointer if found, nullptr otherwise
	*/
	virtual IVolumeCurves *getVolumeCurvesForAttributes(const audio_attributes_t &attr) const = 0;

	/**
	* @brief getVolumeCurvesForStreamType retrieves the Volume Curves interface for the stream
	* @param stream to be considered
	* @return IVolumeCurves interface pointer if found, nullptr otherwise
	*/
	virtual IVolumeCurves *getVolumeCurvesForStreamType(audio_stream_type_t stream) const = 0;

	/**
	* @brief getVolumeCurvesForVolumeGroup retrieves the Volume Curves interface for volume group
	* @param group to be considered
	* @return IVolumeCurves interface pointer if found, nullptr otherwise
	*/
	virtual IVolumeCurves *getVolumeCurvesForVolumeGroup(volume_group_t group) const = 0;

	/**
	* @brief getVolumeGroups retrieves the collection of volume groups.
	* @return vector of volume groups
	*/
	virtual VolumeGroupVector getVolumeGroups() const = 0;

	/**
	* @brief getVolumeGroupForAttributes gets the appropriate volume group to be used for a given
	* Audio Attributes.
	* @param attr to be considered
	* @param fallbackOnDefault if true, will return the fallback volume group if the attributes
	* are not associated to any volume group.
	* @return volume group associated to the given audio attributes, default group if none
	* applicable, VOLUME_GROUP_NONE if no default group defined.
	*/
	virtual volume_group_t getVolumeGroupForAttributes(
	const audio_attributes_t &attr, bool fallbackOnDefault = true) const = 0;

	/**
	* @brief getVolumeGroupForStreamType gets the appropriate volume group to be used for a given
	* legacy stream type
	* @param stream type to be considered
	* @param fallbackOnDefault if true, will return the fallback volume group if the stream type
	* is not associated to any volume group.
	* @return volume group associated to the given stream type, default group if none applicable,
	* VOLUME_GROUP_NONE if no default group defined.
	*/
	virtual volume_group_t getVolumeGroupForStreamType(
	audio_stream_type_t stream, bool fallbackOnDefault = true) const = 0;

	/**
	* @brief listAudioVolumeGroups introspection API to get the Audio Volume Groups, aka
	* former stream aliases in Audio Service, defining volume curves attached to one or more
	* Audio Attributes.
	* @param groups
	* @return NO_ERROR if the volume groups were retrieved successfully, error code otherwise
	*/
	virtual status_t listAudioVolumeGroups(AudioVolumeGroupVector &groups) const = 0;

	/**
	* @brief setDevicesRoleForStrategy sets devices role for a strategy when available. To remove
	* devices role, removeDevicesRoleForStrategy must be called. When devices role is set
	* successfully, previously set devices for the same role and strategy will be removed.
	* @param strategy the audio strategy whose routing will be affected
	* @param role the role of the devices for the strategy. All device roles are defined at
	* system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
	* for setting.
	* @param devices the audio devices to be set
	* @return BAD_VALUE if the strategy or role is invalid,
	* or NO_ERROR if the role of the devices for strategy was set
	*/
	virtual status_t setDevicesRoleForStrategy(product_strategy_t strategy, device_role_t role,
	const AudioDeviceTypeAddrVector &devices) = 0;

	/**
	* @brief removeDevicesRoleForStrategy removes the role of device(s) previously set
	* for the given strategy
	* @param strategy the audio strategy whose routing will be affected
	* @param role the role of the devices for strategy
	* @param devices the audio devices to be removed
	* @return BAD_VALUE if the strategy or role is invalid,
	* or NO_ERROR if the devices for this role was removed
	*/
	virtual status_t removeDevicesRoleForStrategy(product_strategy_t strategy, device_role_t role,
	const AudioDeviceTypeAddrVector &devices) = 0;

	/**
	* @brief clearDevicesRoleForStrategy removes the role of all devices previously set
	* for the given strategy
	* @param strategy the audio strategy whose routing will be affected
	* @param role the role of the devices for strategy
	* @return BAD_VALUE if the strategy or role is invalid,
	* or NO_ERROR if the devices for this role was removed
	*/
	virtual status_t clearDevicesRoleForStrategy(product_strategy_t strategy,
	device_role_t role) = 0;

	/**
	* @brief getDevicesForRoleAndStrategy queries which devices have the specified role for the
	* specified strategy
	* @param strategy the strategy to query
	* @param role the role of the devices to query
	* @param devices returns list of devices with matching role for the specified strategy.
	* DEVICE_ROLE_NONE is invalid as input.
	* @return BAD_VALUE if the strategy or role is invalid,
	* or NAME_NOT_FOUND if no device for the role and strategy was set
	* or NO_ERROR if the devices parameter contains a list of devices
	*/
	virtual status_t getDevicesForRoleAndStrategy(product_strategy_t strategy, device_role_t role,
	AudioDeviceTypeAddrVector &devices) const = 0;

	/**
	* @brief setDevicesRoleForCapturePreset sets devices role for a capture preset when available.
	* To remove devices role, removeDevicesRoleForCapturePreset must be called. Calling
	* clearDevicesRoleForCapturePreset will remove all devices as role. When devices role is set
	* successfully, previously set devices for the same role and capture preset will be removed.
	* @param audioSource the audio capture preset whose routing will be affected
	* @param role the role of the devices for the capture preset. All device roles are defined at
	* system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
	* for setting.
	* @param devices the audio devices to be set
	* @return BAD_VALUE if the capture preset or role is invalid,
	* or NO_ERROR if the role of the devices for capture preset was set
	*/
	virtual status_t setDevicesRoleForCapturePreset(audio_source_t audioSource, device_role_t role,
	const AudioDeviceTypeAddrVector &devices) = 0;

	/**
	* @brief addDevicesRoleForCapturePreset adds devices role for a capture preset when available.
	* To remove devices role, removeDevicesRoleForCapturePreset must be called. Calling
	* clearDevicesRoleForCapturePreset will remove all devices as role.
	* @param audioSource the audio capture preset whose routing will be affected
	* @param role the role of the devices for the capture preset. All device roles are defined at
	* system/media/audio/include/system/audio_policy.h. DEVICE_ROLE_NONE is invalid
	* for setting.
	* @param devices the audio devices to be added
	* @return BAD_VALUE if the capture preset or role is invalid,
	* or NO_ERROR if the role of the devices for capture preset was added
	*/
	virtual status_t addDevicesRoleForCapturePreset(audio_source_t audioSource, device_role_t role,
	const AudioDeviceTypeAddrVector &devices) = 0;

	/**
	* @brief removeDevicesRoleForCapturePreset removes the role of device(s) previously set
	* for the given capture preset
	* @param audioSource the audio capture preset whose routing will be affected
	* @param role the role of the devices for the capture preset
	* @param devices the devices to be removed
	* @return BAD_VALUE if 1) the capture preset is invalid, 2) role is invalid or 3) the list of
	* devices to be removed are not all present as role for a capture preset
	* or NO_ERROR if the devices for this role was removed
	*/
	virtual status_t removeDevicesRoleForCapturePreset(audio_source_t audioSource,
	device_role_t role, const AudioDeviceTypeAddrVector& devices) = 0;

	/**
	* @brief clearDevicesRoleForCapturePreset removes the role of all device(s) previously set
	* for the given capture preset
	* @param audioSource the audio capture preset whose routing will be affected
	* @param role the role of the devices for the capture preset
	* @return BAD_VALUE if the capture preset or role is invalid,
	* or NO_ERROR if the devices for this role was removed
	*/
	virtual status_t clearDevicesRoleForCapturePreset(audio_source_t audioSource,
	device_role_t role);

	/**
	* @brief getDevicesForRoleAndCapturePreset queries which devices have the specified role for
	* the specified capture preset
	* @param audioSource the capture preset to query
	* @param role the role of the devices to query
	* @param devices returns list of devices with matching role for the specified capture preset.
	* DEVICE_ROLE_NONE is invalid as input.
	* @return BAD_VALUE if the capture preset or role is invalid,
	* or NAME_NOT_FOUND if no device for the role and capture preset was set
	* or NO_ERROR if the devices parameter contains a list of devices
	*/
	virtual status_t getDevicesForRoleAndCapturePreset(audio_source_t audioSource,
	device_role_t role, AudioDeviceTypeAddrVector &devices) const = 0;

	/**
	* @brief getActiveMediaDevices returns which devices will most likely to be used for media
	* @param availableDevices all available devices
	* @return collection of active devices
	*/
	virtual DeviceVector getActiveMediaDevices(const DeviceVector& availableDevices) const = 0;

	virtual void dump(String8 *dst) const = 0;

	protected:
	virtual ~EngineInterface() {}
	};

	__attribute__((visibility("default")))
	extern "C" EngineInterface* createEngineInstance();

	__attribute__((visibility("default")))
	extern "C" void destroyEngineInstance(EngineInterface *engine);

	} // namespace android