From 578e943afcd9c818f969502a94375b1a70548bf9 Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Sat, 23 Mar 2019 08:38:21 +0000
Subject: win32: share code to find root prefix of path

Move unc_root_len() from ash to mingw32.c and use it in the new
function root_len(), which can be used in make_directory().

This reduces changes to upstream code and saves a few bytes.
---
 include/mingw.h        |  3 +++
 libbb/make_directory.c | 25 ++-----------------------
 shell/ash.c            | 30 ++----------------------------
 win32/mingw.c          | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 51 deletions(-)

diff --git a/include/mingw.h b/include/mingw.h
index 36c2f6805..7c9423cad 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -522,3 +522,6 @@ ULONGLONG CompatGetTickCount64(void);
 ssize_t get_random_bytes(void *buf, ssize_t count);
 int enumerate_links(const char *file, char *name);
 void hide_console(void);
+
+int unc_root_len(const char *dir);
+int root_len(const char *path);
diff --git a/libbb/make_directory.c b/libbb/make_directory.c
index 9af5552d5..e0fd486d8 100644
--- a/libbb/make_directory.c
+++ b/libbb/make_directory.c
@@ -59,29 +59,8 @@ int FAST_FUNC bb_make_directory(char *path, long mode, int flags)
 
 		if (flags & FILEUTILS_RECUR) {  /* Get the parent */
 #if ENABLE_PLATFORM_MINGW32
-			if (s == path && *s && s[1] == ':') {
-				/* skip drive letter */
-				s += 2;
-			}
-			else if (s == path && s[0] == '/' && s[1] == '/' ) {
-				/* skip UNC server and share */
-				int count = 0;
-				s += 2;
-				while (*s) {
-					if (*s == '/') {
-						do {
-							++s;
-						} while (*s == '/');
-						if (++count == 2) {
-							--s;
-							break;
-						}
-					}
-					else {
-						++s;
-					}
-				}
-			}
+			if (s == path)
+				s += root_len(path);
 #endif
 			/* Bypass leading non-'/'s and then subsequent '/'s */
 			while (*s) {
diff --git a/shell/ash.c b/shell/ash.c
index cd6196640..34ddc14f1 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2860,34 +2860,6 @@ cdopt(void)
 	return flags;
 }
 
-#if ENABLE_PLATFORM_MINGW32
-#define is_path_sep(x) ((x) == '/' || (x) == '\\')
-#define is_unc_path(x) (is_path_sep(x[0]) && is_path_sep(x[1]))
-#define is_root(x) (is_path_sep(x[0]) && x[1] == '\0')
-
-/* Return the length of the root of a UNC path, i.e. the '//host/share'
- * component, or 0 if the path doesn't look like that. */
-static int
-unc_root_len(const char *dir)
-{
-	const char *s = dir + 2;
-	int len;
-
-	if (!is_unc_path(dir))
-		return 0;
-	len = strcspn(s, "/\\");
-	if (len == 0)
-		return 0;
-	s += len + 1;
-	len = strcspn(s, "/\\");
-	if (len == 0)
-		return 0;
-	s += len;
-
-	return s - dir;
-}
-#endif
-
 /*
  * Update curdir (the name of the current directory) in response to a
  * cd command.
@@ -2896,6 +2868,8 @@ static const char *
 updatepwd(const char *dir)
 {
 #if ENABLE_PLATFORM_MINGW32
+# define is_path_sep(x) ((x) == '/' || (x) == '\\')
+# define is_root(x) (is_path_sep(x[0]) && x[1] == '\0')
 	/*
 	 * Due to Windows drive notion, getting pwd is a completely
 	 * different thing. Handle it in a separate routine
diff --git a/win32/mingw.c b/win32/mingw.c
index 0206f6dca..3ee1a2496 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1609,3 +1609,38 @@ void hide_console(void)
 	}
 }
 #endif
+
+#define is_path_sep(x) ((x) == '/' || (x) == '\\')
+#define is_unc_path(x) (is_path_sep(x[0]) && is_path_sep(x[1]))
+
+/* Return the length of the root of a UNC path, i.e. the '//host/share'
+ * component, or 0 if the path doesn't look like that. */
+int unc_root_len(const char *dir)
+{
+	const char *s = dir + 2;
+	int len;
+
+	if (!is_unc_path(dir))
+		return 0;
+	len = strcspn(s, "/\\");
+	if (len == 0)
+		return 0;
+	s += len + 1;
+	len = strcspn(s, "/\\");
+	if (len == 0)
+		return 0;
+	s += len;
+
+	return s - dir;
+}
+
+/* Return the length of the root of a path, i.e. either the drive or
+ * UNC '//host/share', or 0 if the path doesn't look like that. */
+int root_len(const char *path)
+{
+	if (path == NULL)
+		return 0;
+	if (isalpha(*path) && path[1] == ':')
+		return 2;
+	return unc_root_len(path);
+}
-- 
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