src/win32/error.c

   1 /*
   2  * Copyright (C) the libgit2 contributors. All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7
   8 #include "error.h"
   9
  10 #include "utf-conv.h"
  11
  12 #ifdef GIT_WINHTTP
  13 # include <winhttp.h>
  14 #endif
  15
  16 char *git_win32_get_error_message(DWORD error_code)
  17 {
  18         LPWSTR lpMsgBuf = NULL;
  19         HMODULE hModule = NULL;
  20         char *utf8_msg = NULL;
  21         DWORD dwFlags =
  22                 FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS;
  23
  24         if (!error_code)
  25                 return NULL;
  26
  27 #ifdef GIT_WINHTTP
  28         /* Errors raised by WinHTTP are not in the system resource table */
  29         if (error_code >= WINHTTP_ERROR_BASE &&
  30                 error_code <= WINHTTP_ERROR_LAST)
  31                 hModule = GetModuleHandleW(L"winhttp");
  32 #endif
  33
  34         GIT_UNUSED(hModule);
  35
  36         if (hModule)
  37                 dwFlags |= FORMAT_MESSAGE_FROM_HMODULE;
  38         else
  39                 dwFlags |= FORMAT_MESSAGE_FROM_SYSTEM;
  40
  41         if (FormatMessageW(dwFlags, hModule, error_code,
  42                 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
  43                 (LPWSTR)&lpMsgBuf, 0, NULL)) {
  44                 /* Convert the message to UTF-8. If this fails, we will
  45                  * return NULL, which is a condition expected by the caller */
  46                 if (git__utf16_to_8_alloc(&utf8_msg, lpMsgBuf) < 0)
  47                         utf8_msg = NULL;
  48
  49                 LocalFree(lpMsgBuf);
  50         }
  51
  52         return utf8_msg;
  53 }