PIBIO_SENSOR_FINISH_CAPTURE_FN回调函数 (winbio_adapter.h)

项目
03/03/2024

由 Windows 生物识别框架调用，以等待由 SensorAdapterStartCapture 函数启动的捕获操作完成。

语法

PIBIO_SENSOR_FINISH_CAPTURE_FN PibioSensorFinishCaptureFn;

HRESULT PibioSensorFinishCaptureFn(
  [in, out] PWINBIO_PIPELINE Pipeline,
  [out]     PWINBIO_REJECT_DETAIL RejectDetail
)
{...}

参数

[in, out] Pipeline

指向与执行操作的生物识别单元关联的 WINBIO_PIPELINE 结构的指针。

[out] RejectDetail

指向 WINBIO_REJECT_DETAIL 值的指针，该值接收有关捕获生物识别样本失败的其他信息。如果操作成功，则此参数设置为零。为指纹样本定义了以下值：

WINBIO_FP_TOO_HIGH
WINBIO_FP_TOO_LOW
WINBIO_FP_TOO_LEFT
WINBIO_FP_TOO_RIGHT
WINBIO_FP_TOO_FAST
WINBIO_FP_TOO_SLOW
WINBIO_FP_POOR_QUALITY
WINBIO_FP_TOO_SKEWED
WINBIO_FP_TOO_SHORT
WINBIO_FP_MERGE_FAILURE

返回值

如果函数成功，则返回S_OK。如果函数失败，它将返回指示错误的 HRESULT 值。 Windows 生物识别框架将识别以下值。

返回代码	说明
WINBIO_E_BAD_CAPTURE	无法捕获示例。如果返回此错误代码，还必须在 RejectDetail 参数中指定一个指示问题性质的值。
WINBIO_E_CAPTURE_CANCELED	传感器驱动程序返回 ERROR_CANCELLED 或 ERROR_OPERATION_ABORTED。
WINBIO_E_DEVICE_FAILURE	设备发生故障。
WINBIO_E_INVALID_DEVICE_STATE	Pipeline 参数指向的 WINBIO_PIPELINE 结构的 SensorContext 成员为 NULL，或者 SensorHandle 成员设置为 INVALID_HANDLE_VALUE。

注解

Windows 生物识别框架在成功调用 SensorAdapterStartCapture 或调用 SensorAdapterCancel 后调用此函数。如果对 SensorAdapterStartCapture 的调用失败，它不会调用此函数。

当此函数的实现返回时，管道中的数据应已准备好，以便后续调用 SensorAdapterPushDataToEngine 或 SensorAdapterExportSensorData 等函数。

这是一个阻塞函数，仅在传感器 I/O 操作成功、失败或取消后才返回。通常，通过将传感器适配器上下文中的 OVERLAPPED 结构传递给 GetOverlappedResult 函数，使此函数成为块。当 SensorAdapterFinishCapture 返回时，必须向 OVERLAPPED 结构中的 hEvent 句柄发出信号。 GetOverlappedResult 函数在检测到传感器 I/O 操作结束时自动设置此句柄。如果适配器使用其他某种机制来检测 I/O 完成，则必须自行发出事件信号。

示例

以下伪代码显示了此函数的一种可能实现。该示例不编译。必须根据自己的目的调整它。

//////////////////////////////////////////////////////////////////////////////////////////
//
// SensorAdapterFinishCapture
//
// Purpose:
//      Waits for the completion of a capture operation initiated by the 
//      SensorAdapterStartCapture function.
//      
// Parameters:
//      Pipeline     -  Pointer to a WINBIO_PIPELINE structure associated with 
//                      the biometric unit.
//      RejectDetail -  Pointer to a WINBIO_REJECT_DETAIL value that receives 
//                      additional information about the failure to capture a 
//                      biometric sample.
//
static HRESULT
WINAPI
SensorAdapterFinishCapture(
    __inout PWINBIO_PIPELINE Pipeline,
    __out PWINBIO_REJECT_DETAIL RejectDetail
    )
{
    HRESULT hr = S_OK;
    WINBIO_SENSOR_STATUS sensorStatus = WINBIO_SENSOR_FAILURE;
    WINBIO_CAPTURE_PARAMETERS captureParameters = {0};
    BOOL result = TRUE;
    DWORD bytesReturned = 0;

    // Verify that pointer arguments are not NULL.
    if (!ARGUMENT_PRESENT(Pipeline) ||
        !ARGUMENT_PRESENT(RejectDetail))
    {
        hr = E_POINTER;
        goto cleanup;
    }

    // Retrieve the context from the pipeline.
    PWINBIO_SENSOR_CONTEXT sensorContext = 
             (PWINBIO_SENSOR_CONTEXT)Pipeline->SensorContext;

    // Verify the state of the pipeline.
    if (sensorContext == NULL || 
        Pipeline->SensorHandle == INVALID_HANDLE_VALUE)
    {
        return WINBIO_E_INVALID_DEVICE_STATE;
    }

    // Initialize the RejectDetail argument.
    *RejectDetail = 0;

    // Wait for I/O completion. This sample assumes that the I/O operation was 
    // started using the code example shown in the SensorAdapterStartCapture
    // documentation.
    SetLastError(ERROR_SUCCESS);

    result = GetOverlappedResult(
                Pipeline->SensorHandle,
                &sensorContext->Overlapped,
                &bytesReturned,
                TRUE
                );
    if (!result)
    {
        // There was an I/O error.
        return _AdapterGetHresultFromWin32(GetLastError());
    }

    if (bytesReturned == sizeof (DWORD))
    {
        // The buffer is not large enough.  This can happen if a device needs a 
        // bigger buffer depending on the purpose. Allocate a larger buffer and 
        // force the caller to reissue their I/O request.
        DWORD allocationSize = sensorContext->CaptureBuffer->PayloadSize;

        // Allocate at least the minimum buffer size needed to retrieve the 
        // payload structure.
        if (allocationSize < sizeof(WINBIO_CAPTURE_DATA))
        {
            allocationSize = sizeof(WINBIO_CAPTURE_DATA);
        }

        // Free the old buffer and allocate a new one.
        _AdapterRelease(sensorContext->CaptureBuffer);
        sensorContext->CaptureBuffer = NULL;

        sensorContext->CaptureBuffer = 
            (PWINBIO_CAPTURE_DATA)_AdapterAlloc(allocationSize);
        if (sensorContext->CaptureBuffer == NULL)
        {
            sensorContext->CaptureBufferSize = 0;
            return E_OUTOFMEMORY;
        }
        sensorContext->CaptureBufferSize = allocationSize;
        return WINBIO_E_BAD_CAPTURE;
    }

    // Normalize the status value before sending it back to the biometric service.
    if (sensorContext->CaptureBuffer != NULL &&
        sensorContext->CaptureBufferSize >= sizeof (WINBIO_CAPTURE_DATA))
    {
        switch (sensorContext->CaptureBuffer->SensorStatus)
        {
            case WINBIO_SENSOR_ACCEPT:
                // The capture was acceptable.
                break;

            case WINBIO_SENSOR_REJECT:
                // The capture was not acceptable. Overwrite the WinBioHresult value
                // in case it has not been properly set.
                sensorContext->CaptureBuffer->WinBioHresult = WINBIO_E_BAD_CAPTURE;
                break;

            case WINBIO_SENSOR_BUSY:
                // The device is busy. Reset the WinBioHresult value in case it 
                // has not been properly set.
                sensorContext->CaptureBuffer->WinBioHresult = WINBIO_E_DEVICE_BUSY;
                break;

            case WINBIO_SENSOR_READY:
            case WINBIO_SENSOR_NOT_CALIBRATED:
            case WINBIO_SENSOR_FAILURE:
            default:
                // There has been a device failure. Reset the WinBioHresult value
                // in case it has not been properly set.
                sensorContext->CaptureBuffer->WinBioHresult = WINBIO_E_INVALID_DEVICE_STATE;
                break;
        }

        *RejectDetail = sensorContext->CaptureBuffer->RejectDetail;
        hr = sensorContext->CaptureBuffer->WinBioHresult;
    }
    else
    {
        // The buffer is not large enough or the buffer pointer is NULL.
        hr = WINBIO_E_INVALID_DEVICE_STATE;
    }
    return hr;
}

要求

要求	值
最低受支持的客户端	Windows 7 [仅限桌面应用]
最低受支持的服务器	Windows Server 2008 R2 [仅限桌面应用]
目标平台	Windows
标头	winbio_adapter.h (包括 Winbio_adapter.h)