UINT64 GetDynamicPartitionSize()

in IORequestGenerator/IORequestGenerator.cpp [61:171]
102 lines of code
15 McCabe index (conditional complexity)

UINT64 GetDynamicPartitionSize(HANDLE hFile)
{
    assert(NULL != hFile && INVALID_HANDLE_VALUE != hFile);

    UINT64 size = 0;
    VOLUME_DISK_EXTENTS diskExt = {0};
    PVOLUME_DISK_EXTENTS pDiskExt = &diskExt;
    DWORD bytesReturned;

    DWORD status = ERROR_SUCCESS;
    BOOL rslt;

    OVERLAPPED ovlp = {0};
    ovlp.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
    if (ovlp.hEvent == nullptr)
    {
        PrintError("ERROR: Failed to create event (error code: %u)\n", GetLastError());
        return 0;
    }

    rslt = DeviceIoControl(hFile,
                            IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,
                            NULL,
                            0,
                            pDiskExt,
                            sizeof(VOLUME_DISK_EXTENTS),
                            &bytesReturned,
                            &ovlp);
    if (!rslt) {
        status = GetLastError();
        if (status == ERROR_MORE_DATA) {
            status = ERROR_SUCCESS;

            bytesReturned = sizeof(VOLUME_DISK_EXTENTS) + ((pDiskExt->NumberOfDiskExtents - 1) * sizeof(DISK_EXTENT));
            pDiskExt = (PVOLUME_DISK_EXTENTS)LocalAlloc(LPTR, bytesReturned);

            if (pDiskExt)
            {
                rslt = DeviceIoControl(hFile,
                                    IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,
                                    NULL,
                                    0,
                                    pDiskExt,
                                    bytesReturned,
                                    &bytesReturned,
                                    &ovlp);
                if (!rslt)
                {
                    status = GetLastError();
                    if (status == ERROR_IO_PENDING)
                    {
                        if (WAIT_OBJECT_0 != WaitForSingleObject(ovlp.hEvent, INFINITE))
                        {
                            status = GetLastError();
                            PrintError("ERROR: Failed while waiting for event to be signaled (error code: %u)\n", status);
                        }
                        else
                        {
                            status = ERROR_SUCCESS;
                            assert(pDiskExt->NumberOfDiskExtents <= 1);
                        }
                    }
                    else
                    {
                        PrintError("ERROR: Could not obtain dynamic volume extents (error code: %u)\n", status);
                    }
                }
            }
            else
            {
                status = GetLastError();
                PrintError("ERROR: Could not allocate memory (error code: %u)\n", status);
            }
        }
        else if (status == ERROR_IO_PENDING)
        {
            if (WAIT_OBJECT_0 != WaitForSingleObject(ovlp.hEvent, INFINITE))
            {
                status = GetLastError();
                PrintError("ERROR: Failed while waiting for event to be signaled (error code: %u)\n", status);
            }
            else
            {
                status = ERROR_SUCCESS;
                assert(pDiskExt->NumberOfDiskExtents <= 1);
            }
        }
        else
        {
            PrintError("ERROR: Could not obtain dynamic volume extents (error code: %u)\n", status);
        }
    }
    else
    {
        assert(pDiskExt->NumberOfDiskExtents <= 1);
    }

    if (status == ERROR_SUCCESS)
    {
        for (DWORD n = 0; n < pDiskExt->NumberOfDiskExtents; n++) {
            size += pDiskExt->Extents[n].ExtentLength.QuadPart;
        }
    }

    if (pDiskExt && (pDiskExt != &diskExt)) {
        LocalFree(pDiskExt);
    }
    CloseHandle(ovlp.hEvent);

    return size;
}