From be4c6380de40fb19e83df44fe4532275d1d12067 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Sat, 11 Jul 2009 15:44:36 +0000
Subject: [PATCH] (logon_network_drive): Don't assume PATH is an absolute file
 name. (is_slow_fs): New function. (stat): Use it to determine whether to
 issue more system calls to get accurate file attributes, when
 w32-get-true-file-attributes is `local'.

---
 src/w32.c | 54 +++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 37 insertions(+), 17 deletions(-)

diff --git a/src/w32.c b/src/w32.c
index 2a7be366ae..7a414dd6bd 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -2555,12 +2555,23 @@ logon_network_drive (const char *path)
   char share[MAX_PATH];
   int i, n_slashes;
   char drive[4];
+  UINT drvtype;
 
-  sprintf (drive, "%c:\\", path[0]);
+  if (IS_DIRECTORY_SEP (path[0]) && IS_DIRECTORY_SEP (path[1]))
+    drvtype = DRIVE_REMOTE;
+  else if (path[0] == '\0' || path[1] != ':')
+    drvtype = GetDriveType (NULL);
+  else
+    {
+      drive[0] = path[0];
+      drive[1] = ':';
+      drive[2] = '\\';
+      drive[3] = '\0';
+      drvtype = GetDriveType (drive);
+    }
 
   /* Only logon to networked drives.  */
-  if ((!IS_DIRECTORY_SEP (path[0]) || !IS_DIRECTORY_SEP (path[1]))
-      && GetDriveType (drive) != DRIVE_REMOTE)
+  if (drvtype != DRIVE_REMOTE)
     return;
 
   n_slashes = 2;
@@ -3234,6 +3245,28 @@ get_file_owner_and_group (
     }
 }
 
+/* Return non-zero if NAME is a potentially slow filesystem.  */
+int
+is_slow_fs (const char *name)
+{
+  char drive_root[4];
+  UINT devtype;
+
+  if (IS_DIRECTORY_SEP (name[0]) && IS_DIRECTORY_SEP (name[1]))
+    devtype = DRIVE_REMOTE;	   /* assume UNC name is remote */
+  else if (!(strlen (name) >= 2 && IS_DEVICE_SEP (name[1])))
+    devtype = GetDriveType (NULL); /* use root of current drive */
+  else
+    {
+      /* GetDriveType needs the root directory of the drive.  */
+      strncpy (drive_root, name, 2);
+      drive_root[2] = '\\';
+      drive_root[3] = '\0';
+      devtype = GetDriveType (drive_root);
+    }
+  return !(devtype == DRIVE_FIXED || devtype == DRIVE_RAMDISK);
+}
+
 /* MSVC stat function can't cope with UNC names and has other bugs, so
    replace it with our own.  This also allows us to calculate consistent
    inode values without hacks in the main Emacs code. */
@@ -3347,21 +3380,8 @@ stat (const char * path, struct stat * buf)
 	}
     }
 
-  if (IS_DIRECTORY_SEP (name[0]) && IS_DIRECTORY_SEP (name[1]))
-    devtype = DRIVE_REMOTE;	   /* assume UNC name is remote */
-  else if (!(strlen (name) >= 2 && IS_DEVICE_SEP (name[1])))
-    devtype = GetDriveType (NULL); /* use root of current drive */
-  else
-    {
-      /* GetDriveType needs the root directory of NAME's drive.  */
-      strncpy (drive_root, name, 3);
-      drive_root[3] = '\0';
-      devtype = GetDriveType (drive_root);
-    }
-
   if (!(NILP (Vw32_get_true_file_attributes)
-	|| (EQ (Vw32_get_true_file_attributes, Qlocal)
-	    && devtype != DRIVE_FIXED && devtype != DRIVE_RAMDISK))
+	|| (EQ (Vw32_get_true_file_attributes, Qlocal) && !is_slow_fs (name)))
       /* No access rights required to get info.  */
       && (fh = CreateFile (name, 0, 0, NULL, OPEN_EXISTING,
 			   FILE_FLAG_BACKUP_SEMANTICS, NULL))
-- 
2.20.1