IFRDocumentEvents 接口

class CFRDocumentCallback: public IFRDocumentEvents {
public:
    CFRDocumentCallback() : startTime( 0 ) {}
    // 实现 IUnknown 方法
    ULONG STDMETHODCALLTYPE AddRef() { return 1; }
    ULONG STDMETHODCALLTYPE Release() { return 1; }
    HRESULT STDMETHODCALLTYPE QueryInterface( REFIID riid, void** ppObject );
    HRESULT STDMETHODCALLTYPE OnProgress( IFRDocument* document, int percentage, VARIANT_BOOL* ShouldContinue );
    HRESULT STDMETHODCALLTYPE OnWarning( IFRDocument* document, int pageNumber, BSTR recognizerTip, 
        VARIANT_BOOL* ShouldContinue );
    HRESULT STDMETHODCALLTYPE OnPageProcessed( IFRDocument* document, int pageNumber, PageProcessingStageEnum stage );
    void FlushTimer();
    void SetShouldTrackTime( bool _shouldTrackTime );
private:
    time_t startTime;
    bool shouldTrackTime = true;
};
 
// 调用 FlushTimer 方法以重置 startTime
void CFRDocumentCallback::FlushTimer() {
    time( &startTime );
}
 
// 此回调可能用于其他方法，
// 若不再需要超时功能，请将 shouldTrackTime 设置为 FALSE
void CFRDocumentCallback::SetShouldTrackTime( bool _shouldTrackTime ) {
    shouldTrackTime = _shouldTrackTime;
}
 
// 若当前时间与 "startTime" 之差超过某一阈值，
// 处理过程将被中止
HRESULT STDMETHODCALLTYPE CFRDocumentCallback::OnProgress( IFRDocument* frDocument, 
    int percentage, VARIANT_BOOL* shouldTerminate )
{
    if( shouldTrackTime ) {
        time_t currentTime;
        time( &currentTime );
        double seconds = difftime( currentTime, startTime );
        printf( "%f\n", seconds );
        *shouldTerminate = ( seconds > 100 ? VARIANT_TRUE : VARIANT_FALSE );
    }
    return S_OK;
}