audio DevicesFactory
xref: /hardware/interfaces/audio/common/all-versions/default/service/service.cpp
int main(int /* argc */, char* /* argv */ []) {
android::ProcessState::initWithDriver("/dev/vndbinder");
// start a threadpool for vndbinder interactions
android::ProcessState::self()->startThreadPool();
configureRpcThreadpool(16, true /*callerWillJoin*/);
bool fail = registerPassthroughServiceImplementation<audio::V4_0::IDevicesFactory>() != OK &&
registerPassthroughServiceImplementation<audio::V2_0::IDevicesFactory>() != OK; LOG_ALWAYS_FATAL_IF(fail, "Could not register audio core API 2.0 nor 4.0"); fail = registerPassthroughServiceImplementation<audio::effect::V4_0::IEffectsFactory>() != OK && registerPassthroughServiceImplementation<audio::effect::V2_0::IEffectsFactory>() != OK, LOG_ALWAYS_FATAL_IF(fail, "Could not register audio effect API 2.0 nor 4.0"); fail = registerPassthroughServiceImplementation<soundtrigger::V2_1::ISoundTriggerHw>() != OK && registerPassthroughServiceImplementation<soundtrigger::V2_0::ISoundTriggerHw>() != OK, ALOGW_IF(fail, "Could not register soundtrigger API 2.0 nor 2.1"); fail = registerPassthroughServiceImplementation<bluetooth::a2dp::V1_0::IBluetoothAudioOffload>() != OK; ALOGW_IF(fail, "Could not register Bluetooth audio offload 1.0"); joinRpcThreadpool(); }
registerPassthroughServiceImplementation()
xref: /system/libhidl/transport/include/hidl/LegacySupport.h
template<class Interface>
__attribute__((warn_unused_result))
status_t registerPassthroughServiceImplementation(
std::string name = "default") {
sp<Interface> service = Interface::getService(name, true /* getStub */);
if (service == nullptr) {
ALOGE("Could not get passthrough implementation for %s/%s.",
Interface::descriptor, name.c_str());
return EXIT_FAILURE; } LOG_FATAL_IF(service->isRemote(), "Implementation of %s/%s is remote!", Interface::descriptor, name.c_str()); status_t status = service->registerAsService(name); if (status == OK) { ALOGI("Registration complete for %s/%s.", Interface::descriptor, name.c_str()); } else { ALOGE("Could not register service %s/%s (%d).", Interface::descriptor, name.c_str(), status); } return status; }
上面Interface::getService()中的getStub参数为true，所以在ServiceManagement.cpp中的getRawServiceInternal()中，会直接走下面的pm = getPassthroughServiceManager(); pm->get()
所以会执行PassthroughServiceManager::get()，这个函数也在ServiceManagement.cpp里。这个函数会去open so库，以IDevicesFactory为例，会去open [email protected]。open后会call这个so里的HIDL_FETCH_IDevicesFactory()，而这个函数会new一个DevicesFactory对象，如下：
hardware\interfaces\audio\core\all-versions\default\include\core\all-versions\default\DevicesFactory.impl.h
IDevicesFactory* HIDL_FETCH_IDevicesFactory(const char* /* name */) {
return new DevicesFactory();
}
DevicesFactory继承了IDevicesFactory(这个类在soong/.intermediates下)
继续PassthroughServiceManager::get()，这个函数接下来会call RegisterReference(actualFqName, name)，这个actualFqName就是在DevicesFactoryAll.cpp里的IDevicesFactory::descriptor，它的值为[email protected]::IDevicesFactory
所以getRawServiceInternal() return了一个DevicesFactory对象，回到getServiceInternal()，因为DevicesFactory是继承IDevicesFactory，而IDevicesFactory::isRemote()会返回false，所以会执行下面的IType::castFrom(base)，这个函数是直接return parent，即是return base参数，也就是DevicesFactory对象。
然后返回到registerPassthroughServiceImplementation()，然后执行service->registerAsService()，即为执行IDevicesFactory::registerAsService()
上面会去open [email protected]，这个so的查找路径在：
xref: /system/libhidl/base/include/hidl/HidlInternal.h
#define HAL_LIBRARY_PATH_SYSTEM_64BIT "/system/lib64/hw/" #define HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION "/system/lib64/vndk-sp%s/hw/" #define HAL_LIBRARY_PATH_VENDOR_64BIT "/vendor/lib64/hw/" #define HAL_LIBRARY_PATH_ODM_64BIT "/odm/lib64/hw/" #define HAL_LIBRARY_PATH_SYSTEM_32BIT "/system/lib/hw/" #define HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION "/system/lib/vndk-sp%s/hw/" #define HAL_LIBRARY_PATH_VENDOR_32BIT "/vendor/lib/hw/" #define HAL_LIBRARY_PATH_ODM_32BIT "/odm/lib/hw/" #if defined(__LP64__) #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_64BIT #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_64BIT_FOR_VERSION #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_64BIT #define HAL_LIBRARY_PATH_ODM HAL_LIBRARY_PATH_ODM_64BIT #else #define HAL_LIBRARY_PATH_SYSTEM HAL_LIBRARY_PATH_SYSTEM_32BIT #define HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION HAL_LIBRARY_PATH_VNDK_SP_32BIT_FOR_VERSION #define HAL_LIBRARY_PATH_VENDOR HAL_LIBRARY_PATH_VENDOR_32BIT #define HAL_LIBRARY_PATH_ODM HAL_LIBRARY_PATH_ODM_32BIT #endif
那这个[email protected]是哪个makefile去build它的呢？如下：
cc_library_shared { name: "[email protected]", relative_install_path: "hw", proprietary: true, vendor: true, srcs: [ "Conversions.cpp", "Device.cpp", "DevicesFactory.cpp", "ParametersUtil.cpp", "PrimaryDevice.cpp", "Stream.cpp", "StreamIn.cpp", "StreamOut.cpp", ], cflags: [ "-DAUDIO_HAL_VERSION_4_0", ], defaults: ["hidl_defaults"], export_include_dirs: ["include"], shared_libs: [ "libbase", "libcutils", "libfmq", "libhardware", "libhidlbase", "libhidltransport", "liblog", "libutils", "[email protected]", "[email protected]", "[email protected]", "android.hardware.audio.common-util", ], header_libs: [ "android.hardware.audio.common.util@all-versions", "android.hardware.audio.core@all-versions-impl", "libaudioclient_headers", "libaudio_system_headers", "libhardware_headers", "libmedia_headers", ], whole_static_libs: [ "libmedia_helper", ], }