1 files changed, 48 insertions, 0 deletions
diff --git a/src/util/win32/w32_common.h b/src/util/win32/w32_common.h
new file mode 100644
index 000000000..c20b3e85e
--- /dev/null
+++ b/src/util/win32/w32_common.h
@@ -0,0 +1,48 @@
+/*
+ * 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_w32_common_h__
+#define INCLUDE_win32_w32_common_h__
+
+#include <git2/common.h>
+
+/*
+ * 4096 is the max allowed Git path. `MAX_PATH` (260) is the typical max allowed
+ * Windows path length, however win32 Unicode APIs generally allow up to 32,767
+ * if prefixed with "\\?\" (i.e. converted to an NT-style name).
+ */
+#define GIT_WIN_PATH_MAX GIT_PATH_MAX
+
+/*
+ * Provides a large enough buffer to support Windows Git paths:
+ * GIT_WIN_PATH_MAX is 4096, corresponding to a maximum path length of 4095
+ * characters plus a NULL terminator.  Prefixing with "\\?\" adds 4 characters,
+ * but if the original was a UNC path, then we turn "\\server\share" into
+ * "\\?\UNC\server\share".  So we replace the first two characters with
+ * 8 characters, a net gain of 6, so the maximum length is GIT_WIN_PATH_MAX+6.
+ */
+#define GIT_WIN_PATH_UTF16		GIT_WIN_PATH_MAX+6
+
+/* Maximum size of a UTF-8 Win32 Git path.  We remove the "\\?\" or "\\?\UNC\"
+ * prefixes for presentation, bringing us back to 4095 (non-NULL)
+ * characters.  UTF-8 does have 4-byte sequences, but they are encoded in
+ * UTF-16 using surrogate pairs, which takes up the space of two characters.
+ * Two characters in the range U+0800 -> U+FFFF take up more space in UTF-8
+ * (6 bytes) than one surrogate pair (4 bytes).
+ */
+#define GIT_WIN_PATH_UTF8		((GIT_WIN_PATH_MAX - 1) * 3 + 1)
+
+/*
+ * The length of a Windows "shortname", for 8.3 compatibility.
+ */
+#define GIT_WIN_PATH_SHORTNAME  13
+
+/* Win32 path types */
+typedef wchar_t git_win32_path[GIT_WIN_PATH_UTF16];
+typedef char git_win32_utf8_path[GIT_WIN_PATH_UTF8];
+
+#endif