Add git_has_win32_version helper

src/common.h

@@ -29,9 +29,10 @@
 # include "win32/msvc-compat.h"
 # include "win32/mingw-compat.h"
 # include "win32/error.h"
+# include "win32/version.h"
 # ifdef GIT_THREADS
 #	include "win32/pthread.h"
-#endif
+# endif
 
 #else
 

src/transports/winhttp.c

@@ -509,11 +509,7 @@ replay:
 
 			/* Check for Windows 7. This workaround is only necessary on
 			 * Windows Vista and earlier. Windows 7 is version 6.1. */
-			DWORD dwVersion = GetVersion();
-
-			if (LOBYTE(LOWORD(dwVersion)) < 6 ||
-				(LOBYTE(LOWORD(dwVersion)) == 6 &&
-				 HIBYTE(LOWORD(dwVersion)) < 1)) {
+			if (!git_has_win32_version(6, 1)) {
 				wchar_t *location;
 				DWORD location_length;
 				int redirect_cmp;
@@ -991,7 +987,7 @@ static int winhttp_receivepack(
 {
 	/* WinHTTP only supports Transfer-Encoding: chunked
 	 * on Windows Vista (NT 6.0) and higher. */
-	s->chunked = LOBYTE(LOWORD(GetVersion())) >= 6;
+	s->chunked = git_has_win32_version(6, 0);
 
 	if (s->chunked)
 		s->parent.write = winhttp_stream_write_chunked;

src/win32/error.c

@@ -45,7 +45,7 @@ char *git_win32_get_error_message(DWORD error_code)
 		(LPWSTR)&lpMsgBuf, 0, NULL)) {
 
 		/* Invalid code point check supported on Vista+ only */
-		if (LOBYTE(LOWORD(GetVersion())) >= 6)
+		if (git_has_win32_version(6, 0))
 			dwFlags = WC_ERR_INVALID_CHARS;
 		else
 			dwFlags = 0;

src/win32/version.h

+/*
+ * 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.
+ */
+#ifndef INCLUDE_win32_version_h__
+#define INCLUDE_win32_version_h__
+
+#include <windows.h>
+
+GIT_INLINE(int)	git_has_win32_version(int major, int minor)
+{
+	WORD wVersion = LOWORD(GetVersion());
+
+	return LOBYTE(wVersion) > major ||
+		(LOBYTE(wVersion) == major && HIBYTE(wVersion) >= minor);
+}
+
+#endif
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