在connectHelper方法中的makeClient中创建 CameraDeviceClient

Status CameraService::makeClient(const sp<CameraService>& cameraService,
        const sp<IInterface>& cameraCb, const String16& packageName,
        const std::unique_ptr<String16>& featureId, const String8& cameraId, int api1CameraId,
        
    if (halVersion < 0 || halVersion == deviceVersion) {
    
         // Camera2 API route  走到了这里创建了CameraDeviceClient
                sp<hardware::camera2::ICameraDeviceCallbacks> tmp =
                        static_cast<hardware::camera2::ICameraDeviceCallbacks*>(cameraCb.get());
                *client = new CameraDeviceClient(cameraService, tmp, packageName, featureId,
                        cameraId, facing, clientPid, clientUid, servicePid);
            }
            break;
          default:
            // Should not be reachable
            ALOGE("Unknown camera device HAL version: %d", deviceVersion);
            return STATUS_ERROR_FMT(ERROR_INVALID_OPERATION,
                    "Camera device \"%s\" has unknown HAL version %d",
                    cameraId.string(), deviceVersion);
        }
    } 
    return Status::ok();
}

CameraDeviceClient 类中调用初始化了 Camera2ClientBase 的initialize方法

status_t CameraDeviceClient::initializeImpl(TProviderPtr providerPtr, const String8& monitorTags) {
    ATRACE_CALL();
    status_t res;
    // 初始化了 Camera2ClientBase  ,  模板 TProviderPtr 在此处即是 CameraProviderManager 类。
    res = Camera2ClientBase::initialize(providerPtr, monitorTags);
    if (res != OK) {
        return res;
    }

    String8 threadName;
  // 处理图像返回
    mFrameProcessor = new FrameProcessorBase(mDevice);
    threadName = String8::format("CDU-%s-FrameProc", mCameraIdStr.string());
    mFrameProcessor->run(threadName.string());

    mFrameProcessor->registerListener(camera2::FrameProcessorBase::FRAME_PROCESSOR_LISTENER_MIN_ID,
                                      camera2::FrameProcessorBase::FRAME_PROCESSOR_LISTENER_MAX_ID,
                                      /*listener*/this,
                                      /*sendPartials*/true);

    auto deviceInfo = mDevice->info();
    camera_metadata_entry_t physicalKeysEntry = deviceInfo.find(
            ANDROID_REQUEST_AVAILABLE_PHYSICAL_CAMERA_REQUEST_KEYS);
    if (physicalKeysEntry.count > 0) {
        mSupportedPhysicalRequestKeys.insert(mSupportedPhysicalRequestKeys.begin(),
                physicalKeysEntry.data.i32,
                physicalKeysEntry.data.i32 + physicalKeysEntry.count);
    }

    mProviderManager = providerPtr;
    return OK;
}

Camera2ClientBase 的 initializeImpl 方法

template <typename TClientBase>    //对应 CameraDeviceClientBase
template <typename TProviderPtr>  // CameraProviderManager
status_t Camera2ClientBase<TClientBase>::initializeImpl(TProviderPtr providerPtr,
        const String8& monitorTags) {
    ATRACE_CALL();
    ALOGV("%s: Initializing client for camera %s", __FUNCTION__,
          TClientBase::mCameraIdStr.string());
    status_t res;

    // 检查相机的ops 权限
    res = TClientBase::startCameraOps();
    if (res != OK) {
        return res;
    }

    if (mDevice == NULL) {
        ALOGE("%s: Camera %s: No device connected",
                __FUNCTION__, TClientBase::mCameraIdStr.string());
        return NO_INIT;
    }
    //  初始化 Camera3Device 的实例，注意此处传入了 CameraProviderManager。
    res = mDevice->initialize(providerPtr, monitorTags);
    if (res != OK) {
        ALOGE("%s: Camera %s: unable to initialize device: %s (%d)",
                __FUNCTION__, TClientBase::mCameraIdStr.string(), strerror(-res), res);
        return res;
    }

    wp<NotificationListener> weakThis(this);
    // Camera3Device  中设置回调通知
    res = mDevice->setNotifyCallback(weakThis);

    return OK;
}

Camera3Device 中的initialize方法

status_t Camera3Device::initialize(sp<CameraProviderManager> manager, const String8& monitorTags) {
    ATRACE_CALL();
    Mutex::Autolock il(mInterfaceLock);
    Mutex::Autolock l(mLock);

    ALOGV("%s: Initializing HIDL device for camera %s", __FUNCTION__, mId.string());
    if (mStatus != STATUS_UNINITIALIZED) {
        CLOGE("Already initialized!");
        return INVALID_OPERATION;
    }
    if (manager == nullptr) return INVALID_OPERATION;

    sp<ICameraDeviceSession> session;
    ATRACE_BEGIN("CameraHal::openSession");
  //  这里便进入到  CameraProviderManager 的openSession 中去了
    status_t res = manager->openSession(mId.string(), this,
            /*out*/ &session);
    ATRACE_END();
    if (res != OK) {
        SET_ERR_L("Could not open camera session: %s (%d)", strerror(-res), res);
        return res;
    }
}

CameraProviderManager

status_t CameraProviderManager::openSession(const std::string &id,
        const sp<device::V1_0::ICameraDeviceCallback>& callback,
        /*out*/
        sp<device::V1_0::ICameraDevice> *session) {

    std::lock_guard<std::mutex> lock(mInterfaceMutex);

    auto deviceInfo = findDeviceInfoLocked(id,
            /*minVersion*/ {1,0}, /*maxVersion*/ {2,0});
    if (deviceInfo == nullptr) return NAME_NOT_FOUND;

    auto *deviceInfo1 = static_cast<ProviderInfo::DeviceInfo1*>(deviceInfo);
    sp<ProviderInfo> parentProvider = deviceInfo->mParentProvider.promote();
    if (parentProvider == nullptr) {
        return DEAD_OBJECT;
    }
    const sp<provider::V2_4::ICameraProvider> provider = parentProvider->startProviderInterface();
    if (provider == nullptr) {
        return DEAD_OBJECT;
    }
    saveRef(DeviceMode::CAMERA, id, provider);

    auto interface = deviceInfo1->startDeviceInterface<
            CameraProviderManager::ProviderInfo::DeviceInfo1::InterfaceT>();
    if (interface == nullptr) {
        return DEAD_OBJECT;
    }

   // 在这一层调用到 HAl 层的  对应的CameraDevice2 的open
    hardware::Return<Status> status = interface->open(callback);
    if (!status.isOk()) {
        removeRef(DeviceMode::CAMERA, id);
        ALOGE("%s: Transaction error opening a session for camera device %s: %s",
                __FUNCTION__, id.c_str(), status.description().c_str());
        return DEAD_OBJECT;
    }
    if (status == Status::OK) {
        *session = interface;
    }
    return mapToStatusT(status);
}

HAL Service CameraDevice

CameraDevice 的实例实际上在初始化在HAL 层 LegacyCameraProviderImpl 初始化的时候，已经初始化相应的版本了

Return<void> CameraDevice::open(const sp<ICameraDeviceCallback>& callback,
        ICameraDevice::open_cb _hidl_cb)  {
    Status status = initStatus();
    sp<CameraDeviceSession> session = nullptr;

    if (callback == nullptr) {
        ALOGE("%s: cannot open camera %s. callback is null!",
                __FUNCTION__, mCameraId.c_str());
        _hidl_cb(Status::ILLEGAL_ARGUMENT, nullptr);
        return Void();
    }

    if (status != Status::OK) {
        // Provider will never pass initFailed device to client, so
        // this must be a disconnected camera
        ALOGE("%s: cannot open camera %s. camera is disconnected!",
                __FUNCTION__, mCameraId.c_str());
        _hidl_cb(Status::CAMERA_DISCONNECTED, nullptr);
        return Void();
    } else {
        mLock.lock();

        ALOGV("%s: Initializing device for camera %d", __FUNCTION__, mCameraIdInt);
        session = mSession.promote();
        if (session != nullptr && !session->isClosed()) {
            ALOGE("%s: cannot open an already opened camera!", __FUNCTION__);
            mLock.unlock();
            _hidl_cb(Status::CAMERA_IN_USE, nullptr);
            return Void();
        }

        /** Open HAL device */
        status_t res;
        camera3_device_t *device;

        ATRACE_BEGIN("camera3->open");
        // 这里就是拿到的驱动 对象封装，然后调用open 打开camera
        res = mModule->open(mCameraId.c_str(),
                reinterpret_cast<hw_device_t**>(&device));
        ATRACE_END();

        if (res != OK) {
            ALOGE("%s: cannot open camera %s!", __FUNCTION__, mCameraId.c_str());
            mLock.unlock();
            _hidl_cb(getHidlStatus(res), nullptr);
            return Void();
        }

        /** Cross-check device version */
        if (device->common.version < CAMERA_DEVICE_API_VERSION_3_2) {
            ALOGE("%s: Could not open camera: "
                    "Camera device should be at least %x, reports %x instead",
                    __FUNCTION__,
                    CAMERA_DEVICE_API_VERSION_3_2,
                    device->common.version);
            device->common.close(&device->common);
            mLock.unlock();
            _hidl_cb(Status::ILLEGAL_ARGUMENT, nullptr);
            return Void();
        }

        struct camera_info info;
        res = mModule->getCameraInfo(mCameraIdInt, &info);
        if (res != OK) {
            ALOGE("%s: Could not open camera: getCameraInfo failed", __FUNCTION__);
            device->common.close(&device->common);
            mLock.unlock();
            _hidl_cb(Status::ILLEGAL_ARGUMENT, nullptr);
            return Void();
        }
       // 创建了 CameraDeviceSession
        session = createSession(
                device, info.static_camera_characteristics, callback);
        if (session == nullptr) {
            ALOGE("%s: camera device session allocation failed", __FUNCTION__);
            mLock.unlock();
            _hidl_cb(Status::INTERNAL_ERROR, nullptr);
            return Void();
        }
        if (session->isInitFailed()) {
            ALOGE("%s: camera device session init failed", __FUNCTION__);
            session = nullptr;
            mLock.unlock();
            _hidl_cb(Status::INTERNAL_ERROR, nullptr);
            return Void();
        }
        mSession = session;

        IF_ALOGV() {
            session->getInterface()->interfaceChain([](
                ::android::hardware::hidl_vec<::android::hardware::hidl_string> interfaceChain) {
                    ALOGV("Session interface chain:");
                    for (const auto& iface : interfaceChain) {
                        ALOGV("  %s", iface.c_str());
                    }
                });
        }
        mLock.unlock();
    }
    _hidl_cb(status, session->getInterface());
    return Void();
}