Android Camera進程間通訊類總結

時間  2019-11-06
標籤 android camera 進程 通訊 總結 欄目 Android 简体版
原文   原文鏈接

《Android Camera架構》
《Android Camera進程間通訊類總結》
《Android Camera模塊解析之拍照》
《Android Camera模塊解析之視頻錄製》
《Android Camera原理之CameraDeviceCallbacks回調模塊》
《Android Camera原理之openCamera模塊(一)》
《Android Camera原理之openCamera模塊(二)》
《Android Camera原理之createCaptureSession模塊》
《Android Camera原理之setRepeatingRequest與capture模塊》
《Android Camera原理之編譯》
《Android Camera原理之camera provider啓動》
《Android Camera原理之cameraserver與cameraprovider是怎樣聯繫的》
《Android Camera原理之camera service與camera provider session會話與capture request輪轉》
《Android Camera原理之camera HAL底層數據結構與類總結》
《Android Camera原理之camera service類與接口關係》java

咱們直達camera模塊的代碼根據層次能夠分爲下面幾層，開發者直接接觸的是Camera api的部分，Camera api會經過Binder IPC方式調用到Camera服務部分，可是這部分代碼實在繁雜，須要將這部分IPC聯繫的方式總結一些，方便後來人方便的學習這一塊的內容。android

  • Camera api部分：
    frameworks/base/core/java/android/hardware/camera2
  • Camera JNI部分：
    frameworks/base/core/jni/android_hardware_Camera.cpp
    編譯選項在目錄下的Android.bp
    make libandroid_runtime -j1
  • Camera UI庫部分：
    frameworks/av/camera/
    編譯選項在目錄下的Android.bp
    make libcamera_client -j1
  • Camera服務部分：
    frameworks/av/services/camera/libcameraservice/
    編譯選項在目錄下的Android.mk
    make libcameraservice -j1
  • Camera HAL部分：
    hardware/qcom/camera/

首先你們關注一下這個代碼路徑：frameworks/av/camera/aidl/ 這裏是和cameraservice端交互的橋樑。api


cameraservice端的代碼在frameworks/av/services/camera/libcameraservice/下面。session

1.ICameraDeviceUser.aidl

這個aidl文件會自動生成：
./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/camera2/ICameraDeviceUser.h數據結構

#ifndef AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_I_CAMERA_DEVICE_USER_H_
#define AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_I_CAMERA_DEVICE_USER_H_

#include <binder/IBinder.h>
#include <binder/IInterface.h>
#include <binder/Status.h>
#include <camera/CameraMetadata.h>
#include <camera/camera2/CaptureRequest.h>
#include <camera/camera2/OutputConfiguration.h>
#include <camera/camera2/SubmitInfo.h>
#include <cstdint>
#include <gui/view/Surface.h>
#include <utils/StrongPointer.h>
#include <vector>

namespace android {

namespace hardware {

namespace camera2 {

class ICameraDeviceUser : public ::android::IInterface {
public:
  DECLARE_META_INTERFACE(CameraDeviceUser)
  enum  : int32_t {
    NO_IN_FLIGHT_REPEATING_FRAMES = -1,
    NORMAL_MODE = 0,
    CONSTRAINED_HIGH_SPEED_MODE = 1,
    VENDOR_MODE_START = 32768,
    TEMPLATE_PREVIEW = 1,
    TEMPLATE_STILL_CAPTURE = 2,
    TEMPLATE_RECORD = 3,
    TEMPLATE_VIDEO_SNAPSHOT = 4,
    TEMPLATE_ZERO_SHUTTER_LAG = 5,
    TEMPLATE_MANUAL = 6,
  };
  virtual ::android::binder::Status disconnect() = 0;
  virtual ::android::binder::Status submitRequest(const ::android::hardware::camera2::CaptureRequest& request, bool streaming, ::android::hardware::camera2::utils::SubmitInfo* _aidl_return) = 0;
  virtual ::android::binder::Status submitRequestList(const ::std::vector<::android::hardware::camera2::CaptureRequest>& requestList, bool streaming, ::android::hardware::camera2::utils::SubmitInfo* _aidl_return) = 0;
  virtual ::android::binder::Status cancelRequest(int32_t requestId, int64_t* _aidl_return) = 0;
  virtual ::android::binder::Status beginConfigure() = 0;
  virtual ::android::binder::Status endConfigure(int32_t operatingMode, const ::android::hardware::camera2::impl::CameraMetadataNative& sessionParams) = 0;
  virtual ::android::binder::Status deleteStream(int32_t streamId) = 0;
  virtual ::android::binder::Status createStream(const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration, int32_t* _aidl_return) = 0;
  virtual ::android::binder::Status createInputStream(int32_t width, int32_t height, int32_t format, int32_t* _aidl_return) = 0;
  virtual ::android::binder::Status getInputSurface(::android::view::Surface* _aidl_return) = 0;
  virtual ::android::binder::Status createDefaultRequest(int32_t templateId, ::android::hardware::camera2::impl::CameraMetadataNative* _aidl_return) = 0;
  virtual ::android::binder::Status getCameraInfo(::android::hardware::camera2::impl::CameraMetadataNative* _aidl_return) = 0;
  virtual ::android::binder::Status waitUntilIdle() = 0;
  virtual ::android::binder::Status flush(int64_t* _aidl_return) = 0;
  virtual ::android::binder::Status prepare(int32_t streamId) = 0;
  virtual ::android::binder::Status tearDown(int32_t streamId) = 0;
  virtual ::android::binder::Status prepare2(int32_t maxCount, int32_t streamId) = 0;
  virtual ::android::binder::Status updateOutputConfiguration(int32_t streamId, const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration) = 0;
  virtual ::android::binder::Status finalizeOutputConfigurations(int32_t streamId, const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration) = 0;
  enum Call {
    DISCONNECT = ::android::IBinder::FIRST_CALL_TRANSACTION + 0,
    SUBMITREQUEST = ::android::IBinder::FIRST_CALL_TRANSACTION + 1,
    SUBMITREQUESTLIST = ::android::IBinder::FIRST_CALL_TRANSACTION + 2,
    CANCELREQUEST = ::android::IBinder::FIRST_CALL_TRANSACTION + 3,
    BEGINCONFIGURE = ::android::IBinder::FIRST_CALL_TRANSACTION + 4,
    ENDCONFIGURE = ::android::IBinder::FIRST_CALL_TRANSACTION + 5,
    DELETESTREAM = ::android::IBinder::FIRST_CALL_TRANSACTION + 6,
    CREATESTREAM = ::android::IBinder::FIRST_CALL_TRANSACTION + 7,
    CREATEINPUTSTREAM = ::android::IBinder::FIRST_CALL_TRANSACTION + 8,
    GETINPUTSURFACE = ::android::IBinder::FIRST_CALL_TRANSACTION + 9,
    CREATEDEFAULTREQUEST = ::android::IBinder::FIRST_CALL_TRANSACTION + 10,
    GETCAMERAINFO = ::android::IBinder::FIRST_CALL_TRANSACTION + 11,
    WAITUNTILIDLE = ::android::IBinder::FIRST_CALL_TRANSACTION + 12,
    FLUSH = ::android::IBinder::FIRST_CALL_TRANSACTION + 13,
    PREPARE = ::android::IBinder::FIRST_CALL_TRANSACTION + 14,
    TEARDOWN = ::android::IBinder::FIRST_CALL_TRANSACTION + 15,
    PREPARE2 = ::android::IBinder::FIRST_CALL_TRANSACTION + 16,
    UPDATEOUTPUTCONFIGURATION = ::android::IBinder::FIRST_CALL_TRANSACTION + 17,
    FINALIZEOUTPUTCONFIGURATIONS = ::android::IBinder::FIRST_CALL_TRANSACTION + 18,
  };
};  // class ICameraDeviceUser

class ICameraDeviceUserDefault : public ICameraDeviceUser {
public:
  ::android::IBinder* onAsBinder() override;
  ::android::binder::Status disconnect() override;
  ::android::binder::Status submitRequest(const ::android::hardware::camera2::CaptureRequest& request, bool streaming, ::android::hardware::camera2::utils::SubmitInfo* _aidl_return) override;
  ::android::binder::Status submitRequestList(const ::std::vector<::android::hardware::camera2::CaptureRequest>& requestList, bool streaming, ::android::hardware::camera2::utils::SubmitInfo* _aidl_return) override;
  ::android::binder::Status cancelRequest(int32_t requestId, int64_t* _aidl_return) override;
  ::android::binder::Status beginConfigure() override;
  ::android::binder::Status endConfigure(int32_t operatingMode, const ::android::hardware::camera2::impl::CameraMetadataNative& sessionParams) override;
  ::android::binder::Status deleteStream(int32_t streamId) override;
  ::android::binder::Status createStream(const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration, int32_t* _aidl_return) override;
  ::android::binder::Status createInputStream(int32_t width, int32_t height, int32_t format, int32_t* _aidl_return) override;
  ::android::binder::Status getInputSurface(::android::view::Surface* _aidl_return) override;
  ::android::binder::Status createDefaultRequest(int32_t templateId, ::android::hardware::camera2::impl::CameraMetadataNative* _aidl_return) override;
  ::android::binder::Status getCameraInfo(::android::hardware::camera2::impl::CameraMetadataNative* _aidl_return) override;
  ::android::binder::Status waitUntilIdle() override;
  ::android::binder::Status flush(int64_t* _aidl_return) override;
  ::android::binder::Status prepare(int32_t streamId) override;
  ::android::binder::Status tearDown(int32_t streamId) override;
  ::android::binder::Status prepare2(int32_t maxCount, int32_t streamId) override;
  ::android::binder::Status updateOutputConfiguration(int32_t streamId, const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration) override;
  ::android::binder::Status finalizeOutputConfigurations(int32_t streamId, const ::android::hardware::camera2::params::OutputConfiguration& outputConfiguration) override;

};

}  // namespace camera2

}  // namespace hardware

}  // namespace android

#endif  // AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_I_CAMERA_DEVICE_USER_H_

./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/camera2/BnCameraDeviceUser.h繼承了ICameraDeviceUser.h架構

#ifndef AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_BN_CAMERA_DEVICE_USER_H_
#define AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_BN_CAMERA_DEVICE_USER_H_

#include <binder/IInterface.h>
#include <android/hardware/camera2/ICameraDeviceUser.h>

namespace android {

namespace hardware {

namespace camera2 {

class BnCameraDeviceUser : public ::android::BnInterface<ICameraDeviceUser> {
public:
  ::android::status_t onTransact(uint32_t _aidl_code, const ::android::Parcel& _aidl_data, ::android::Parcel* _aidl_reply, uint32_t _aidl_flags = 0) override;
};  // class BnCameraDeviceUser

}  // namespace camera2

}  // namespace hardware

}  // namespace android

#endif  // AIDL_GENERATED_ANDROID_HARDWARE_CAMERA2_BN_CAMERA_DEVICE_USER_H_

./frameworks/av/services/camera/libcameraservice/api2/CameraDeviceClient.h中又發現了繼承BnCameraDeviceUser.h的代碼。ide

struct CameraDeviceClientBase :
         public CameraService::BasicClient,
         public hardware::camera2::BnCameraDeviceUser
{
    typedef hardware::camera2::ICameraDeviceCallbacks TCamCallbacks;

    const sp<hardware::camera2::ICameraDeviceCallbacks>& getRemoteCallback() {
        return mRemoteCallback;
    }

protected:
    CameraDeviceClientBase(const sp<CameraService>& cameraService,
            const sp<hardware::camera2::ICameraDeviceCallbacks>& remoteCallback,
            const String16& clientPackageName,
            const String8& cameraId,
            int api1CameraId,
            int cameraFacing,
            int clientPid,
            uid_t clientUid,
            int servicePid);

    sp<hardware::camera2::ICameraDeviceCallbacks> mRemoteCallback;
};

class CameraDeviceClient :
        public Camera2ClientBase<CameraDeviceClientBase>,
        public camera2::FrameProcessorBase::FilteredListener
{
//......
}

這個IPC調用時爲了操做底層的Camera Device，獲取camera device重要信息，並操做Camera Device，提供了int createStream(in OutputConfiguration outputConfiguration);來建立captute session機制，Surface getInputSurface();來返回相應的輸入流。學習

2.ICameraDeviceCallbacks.aidl

./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/camera2/ICameraDeviceCallbacks.h
| |
| |
./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/camera2/BnCameraDeviceCallbacks.h
| |
| |
frameworks/av/camera/ndk/impl/ACameraDevice.hui

// Callbacks from camera service
    class ServiceCallback : public hardware::camera2::BnCameraDeviceCallbacks {
      public:
        explicit ServiceCallback(CameraDevice* device) : mDevice(device) {}
        binder::Status onDeviceError(int32_t errorCode,
                           const CaptureResultExtras& resultExtras) override;
        binder::Status onDeviceIdle() override;
        binder::Status onCaptureStarted(const CaptureResultExtras& resultExtras,
                              int64_t timestamp) override;
        binder::Status onResultReceived(const CameraMetadata& metadata,
                              const CaptureResultExtras& resultExtras,
                              const std::vector<PhysicalCaptureResultInfo>& physicalResultInfos) override;
        binder::Status onPrepared(int streamId) override;
        binder::Status onRequestQueueEmpty() override;
        binder::Status onRepeatingRequestError(int64_t lastFrameNumber,
                int32_t stoppedSequenceId) override;
      private:
        const wp<CameraDevice> mDevice;
    };

這是獲取當前Camera Device狀態的回調，在操做camera device以前須要判斷當前的camera是否可用。spa

3.ICameraService.aidl

./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/ICameraService.h
| |
| |
./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/BnCameraService.h
| |
| |
frameworks/av/services/camera/libcameraservice/CameraService.h

class CameraService :
    public BinderService<CameraService>,
    public virtual ::android::hardware::BnCameraService,
    public virtual IBinder::DeathRecipient,
    public virtual CameraProviderManager::StatusListener
{
//......
}

這個Camera Service的主類，用戶進程中操做camera核心功能：connectDevice、設置閃光燈等等操做都是經過IPC調用camera service實現的。

4.ICameraServiceProxy.aidl

./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/ICameraServiceProxy.h
| |
| |
./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/BnCameraServiceProxy.h
| |
| |
frameworks/base/services/core/java/com/android/server/camera/CameraServiceProxy.java

private final ICameraServiceProxy.Stub mCameraServiceProxy = new ICameraServiceProxy.Stub() {
        @Override
        public void pingForUserUpdate() {
            if (Binder.getCallingUid() != Process.CAMERASERVER_UID) {
                Slog.e(TAG, "Calling UID: " + Binder.getCallingUid() + " doesn't match expected " +
                        " camera service UID!");
                return;
            }
            notifySwitchWithRetries(30);
        }

        @Override
        public void notifyCameraState(String cameraId, int newCameraState, int facing,
                String clientName, int apiLevel) {
            if (Binder.getCallingUid() != Process.CAMERASERVER_UID) {
                Slog.e(TAG, "Calling UID: " + Binder.getCallingUid() + " doesn't match expected " +
                        " camera service UID!");
                return;
            }
            String state = cameraStateToString(newCameraState);
            String facingStr = cameraFacingToString(facing);
            if (DEBUG) Slog.v(TAG, "Camera " + cameraId + " facing " + facingStr + " state now " +
                    state + " for client " + clientName + " API Level " + apiLevel);

            updateActivityCount(cameraId, newCameraState, facing, clientName, apiLevel);
        }
    };

5.ICameraServiceListener.aidl

./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/ICameraServiceListener.h
| |
| |
./out/soong/.intermediates/frameworks/av/camera/libcamera_client/android_arm_armv7-a-neon_core_shared_platform/gen/aidl/android/hardware/BnCameraServiceListener.h
| |
| |
frameworks/base/core/java/android/hardware/camera2/CameraManager.java

private static final class CameraManagerGlobal extends ICameraServiceListener.Stub
            implements IBinder.DeathRecipient {
    }

6.其餘aidl文件

其餘的aidl文件都是IPC間傳輸的Parcelable類型的數據，例如CaptureRequest.aidl就是IPC中相機捕獲請求的數據，CameraInfo.aidl就是IPC中 camera數據的集合。

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