1 files changed, 53 insertions, 0 deletions
diff --git a/src/util/win32/error.c b/src/util/win32/error.c
new file mode 100644
index 000000000..3a52fb5a9
--- /dev/null
+++ b/src/util/win32/error.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "error.h"
+
+#include "utf-conv.h"
+
+#ifdef GIT_WINHTTP
+# include <winhttp.h>
+#endif
+
+char *git_win32_get_error_message(DWORD error_code)
+{
+	LPWSTR lpMsgBuf = NULL;
+	HMODULE hModule = NULL;
+	char *utf8_msg = NULL;
+	DWORD dwFlags =
+		FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS;
+
+	if (!error_code)
+		return NULL;
+
+#ifdef GIT_WINHTTP
+	/* Errors raised by WinHTTP are not in the system resource table */
+	if (error_code >= WINHTTP_ERROR_BASE &&
+		error_code <= WINHTTP_ERROR_LAST)
+		hModule = GetModuleHandleW(L"winhttp");
+#endif
+
+	GIT_UNUSED(hModule);
+
+	if (hModule)
+		dwFlags |= FORMAT_MESSAGE_FROM_HMODULE;
+	else
+		dwFlags |= FORMAT_MESSAGE_FROM_SYSTEM;
+
+	if (FormatMessageW(dwFlags, hModule, error_code,
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+		(LPWSTR)&lpMsgBuf, 0, NULL)) {
+		/* Convert the message to UTF-8. If this fails, we will
+		 * return NULL, which is a condition expected by the caller */
+		if (git__utf16_to_8_alloc(&utf8_msg, lpMsgBuf) < 0)
+			utf8_msg = NULL;
+
+		LocalFree(lpMsgBuf);
+	}
+
+	return utf8_msg;
+}