Notepad3/grepWinNP3/sktoolslib_mod/FormatMessageWrapper.h
2020-04-17 14:19:38 +02:00

73 lines
2.3 KiB
C++

// sktoolslib - common files for SK tools
// Copyright (C) 2012, 2017 - Stefan Kueng
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
#pragma once
/**
* A wrapper class for calling the FormatMessage() Win32 function and controlling
* the lifetime of the allocated error message buffer.
*/
class CFormatMessageWrapper
{
private:
LPTSTR buffer;
DWORD result;
void release();
void obtainMessage() { obtainMessage(::GetLastError()); }
void obtainMessage(DWORD errorCode);
public:
CFormatMessageWrapper() : buffer(nullptr), result(0) { obtainMessage(); }
CFormatMessageWrapper(DWORD lastError) : buffer(nullptr), result(0) { obtainMessage(lastError); }
~CFormatMessageWrapper() { release(); }
operator LPCTSTR() const { return buffer; }
operator bool() const { return result != 0; }
bool operator!() const { return result == 0; }
LPCTSTR c_str() const { return buffer; }
};
inline void CFormatMessageWrapper::obtainMessage(DWORD errorCode)
{
// First of all release the buffer to make it possible to call this
// method more than once on the same object.
release();
result = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
nullptr,
errorCode,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR)&buffer,
0,
nullptr
);
}
inline void CFormatMessageWrapper::release()
{
if (buffer != 0)
{
LocalFree(buffer);
buffer = 0;
}
result = 0;
}