Fix bug #13262 with crashes in completion on MS-Windows with non-ASCII filenames.

 src/fileio.c (file_name_as_directory, directory_file_name): Accept
 an additional argument MULTIBYTE to indicate whether the input C
 came from a multibyte or a unibyte Lisp string; all callers
 adjusted.  Don't assume the input string is always multibyte.
 (Ffile_name_directory) [DOS_NT]: Handle unibyte strings correctly:
 don't ENCODE_FILE them, and return a unibyte string if the input
 was unibyte.
 (Fexpand_file_name): Don't mix unibyte with multibyte strings, and
 don't assume the input strings will always be multibyte.  If the
 input strings are multibyte, decode strings obtained from C
 library functions.

2 files changed, 124 insertions, 47 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index e8d5449a99e..c8cc486a9de 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,18 @@
+2012-12-24  Eli Zaretskii  <eliz@gnu.org>
+
+        * fileio.c (file_name_as_directory, directory_file_name): Accept
+        an additional argument MULTIBYTE to indicate whether the input C
+        came from a multibyte or a unibyte Lisp string; all callers
+        adjusted.  Don't assume the input string is always multibyte.
+        (Bug#13262)
+        (Ffile_name_directory) [DOS_NT]: Handle unibyte strings correctly:
+        don't ENCODE_FILE them, and return a unibyte string if the input
+        was unibyte.
+        (Fexpand_file_name): Don't mix unibyte with multibyte strings, and
+        don't assume the input strings will always be multibyte.  If the
+        input strings are multibyte, decode strings obtained from C
+        library functions.
+
 2012-12-22  Martin Rudalics  <rudalics@gmx.at>
 
         * window.c (Fselect_window): Reword doc-string (Bug#13248).
diff --git a/src/fileio.c b/src/fileio.c
index b0c319cfa62..2d72583e506 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -373,12 +373,26 @@ Given a Unix syntax file name, returns a string ending in slash.  */)
             strcat (res, "/");
           beg = res;
           p = beg + strlen (beg);
+          dostounix_filename (beg);
+          tem_fn = make_specified_string (beg, -1, p - beg,
+                                          STRING_MULTIBYTE (filename));
         }
+      else
+        tem_fn = make_specified_string (beg - 2, -1, p - beg + 2,
+                                        STRING_MULTIBYTE (filename));
+    }
+  else if (STRING_MULTIBYTE (filename))
+    {
+      tem_fn = ENCODE_FILE (make_specified_string (beg, -1, p - beg, 1));
+      dostounix_filename (SSDATA (tem_fn));
+      tem_fn = DECODE_FILE (tem_fn);
+    }
+  else
+    {
+      dostounix_filename (beg);
+      tem_fn = make_specified_string (beg, -1, p - beg, 0);
     }
-  tem_fn = ENCODE_FILE (make_specified_string (beg, -1, p - beg,
-                                               STRING_MULTIBYTE (filename)));
-  dostounix_filename (SSDATA (tem_fn));
-  return DECODE_FILE (tem_fn);
+  return tem_fn;
 #else  /* DOS_NT */
   return make_specified_string (beg, -1, p - beg, STRING_MULTIBYTE (filename));
 #endif  /* DOS_NT */
@@ -453,12 +467,14 @@ get a current directory to run processes in.  */)
   return Ffile_name_directory (filename);
 }
 
-/* Convert from file name SRC of length SRCLEN to directory name
-   in DST.  On UNIX, just make sure there is a terminating /.
-   Return the length of DST in bytes.  */
+/* Convert from file name SRC of length SRCLEN to directory name in
+   DST.  MULTIBYTE non-zero means the file name in SRC is a multibyte
+   string.  On UNIX, just make sure there is a terminating /.  Return
+   the length of DST in bytes.  */
 
 static ptrdiff_t
-file_name_as_directory (char *dst, const char *src, ptrdiff_t srclen)
+file_name_as_directory (char *dst, const char *src, ptrdiff_t srclen,
+                        bool multibyte)
 {
   if (srclen == 0)
     {
@@ -477,14 +493,17 @@ file_name_as_directory (char *dst, const char *src, ptrdiff_t srclen)
       srclen++;
     }
 #ifdef DOS_NT
-  {
-    Lisp_Object tem_fn = make_specified_string (dst, -1, srclen, 1);
+  if (multibyte)
+    {
+      Lisp_Object tem_fn = make_specified_string (dst, -1, srclen, 1);
 
-    tem_fn = ENCODE_FILE (tem_fn);
-    dostounix_filename (SSDATA (tem_fn));
-    tem_fn = DECODE_FILE (tem_fn);
-    memcpy (dst, SSDATA (tem_fn), (srclen = SBYTES (tem_fn)) + 1);
-  }
+      tem_fn = ENCODE_FILE (tem_fn);
+      dostounix_filename (SSDATA (tem_fn));
+      tem_fn = DECODE_FILE (tem_fn);
+      memcpy (dst, SSDATA (tem_fn), (srclen = SBYTES (tem_fn)) + 1);
+    }
+  else
+    dostounix_filename (dst);
 #endif
   return srclen;
 }
@@ -520,16 +539,18 @@ For a Unix-syntax file name, just appends a slash.  */)
     }
 
   buf = alloca (SBYTES (file) + 10);
-  length = file_name_as_directory (buf, SSDATA (file), SBYTES (file));
+  length = file_name_as_directory (buf, SSDATA (file), SBYTES (file),
+                                   STRING_MULTIBYTE (file));
   return make_specified_string (buf, -1, length, STRING_MULTIBYTE (file));
 }
 
-/* Convert from directory name SRC of length SRCLEN to
-   file name in DST.  On UNIX, just make sure there isn't
-   a terminating /.  Return the length of DST in bytes.  */
+/* Convert from directory name SRC of length SRCLEN to file name in
+   DST.  MULTIBYTE non-zero means the file name in SRC is a multibyte
+   string.  On UNIX, just make sure there isn't a terminating /.
+   Return the length of DST in bytes.  */
 
 static ptrdiff_t
-directory_file_name (char *dst, char *src, ptrdiff_t srclen)
+directory_file_name (char *dst, char *src, ptrdiff_t srclen, bool multibyte)
 {
   /* Process as Unix format: just remove any final slash.
      But leave "/" unchanged; do not change it to "".  */
@@ -545,14 +566,17 @@ directory_file_name (char *dst, char *src, ptrdiff_t srclen)
       srclen--;
     }
 #ifdef DOS_NT
-  {
-    Lisp_Object tem_fn = make_specified_string (dst, -1, srclen, 1);
+  if (multibyte)
+    {
+      Lisp_Object tem_fn = make_specified_string (dst, -1, srclen, 1);
 
-    tem_fn = ENCODE_FILE (tem_fn);
-    dostounix_filename (SSDATA (tem_fn));
-    tem_fn = DECODE_FILE (tem_fn);
-    memcpy (dst, SSDATA (tem_fn), (srclen = SBYTES (tem_fn)) + 1);
-  }
+      tem_fn = ENCODE_FILE (tem_fn);
+      dostounix_filename (SSDATA (tem_fn));
+      tem_fn = DECODE_FILE (tem_fn);
+      memcpy (dst, SSDATA (tem_fn), (srclen = SBYTES (tem_fn)) + 1);
+    }
+  else
+    dostounix_filename (dst);
 #endif
   return srclen;
 }
@@ -588,7 +612,8 @@ In Unix-syntax, this function just removes the final slash.  */)
     }
 
   buf = alloca (SBYTES (directory) + 20);
-  length = directory_file_name (buf, SSDATA (directory), SBYTES (directory));
+  length = directory_file_name (buf, SSDATA (directory), SBYTES (directory),
+                                STRING_MULTIBYTE (directory));
   return make_specified_string (buf, -1, length, STRING_MULTIBYTE (directory));
 }
 
@@ -1038,7 +1063,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
           /* `egetenv' may return a unibyte string, which will bite us since
              we expect the directory to be multibyte.  */
           tem = build_string (newdir);
-          if (!STRING_MULTIBYTE (tem))
+          if (multibyte && !STRING_MULTIBYTE (tem))
             {
               hdir = DECODE_FILE (tem);
               newdir = SSDATA (hdir);
@@ -1060,7 +1085,18 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
           unblock_input ();
           if (pw)
             {
+              Lisp_Object tem;
+
               newdir = pw->pw_dir;
+              /* `getpwnam' may return a unibyte string, which will
+                 bite us since we expect the directory to be
+                 multibyte.  */
+              tem = build_string (newdir);
+              if (multibyte && !STRING_MULTIBYTE (tem))
+                {
+                  hdir = DECODE_FILE (tem);
+                  newdir = SSDATA (hdir);
+                }
               nm = p;
 #ifdef DOS_NT
               collapse_newdir = 0;
@@ -1084,6 +1120,13 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
           adir = alloca (MAXPATHLEN + 1);
           if (!getdefdir (c_toupper (drive) - 'A' + 1, adir))
             adir = NULL;
+          else if (multibyte)
+            {
+              Lisp_Object tem = build_string (adir);
+
+              tem = DECODE_FILE (tem);
+              memcpy (adir, SSDATA (tem), SBYTES (tem) + 1);
+            }
         }
       if (!adir)
         {
@@ -1142,6 +1185,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
              indirectly by prepending newdir to nm if necessary, and using
              cwd (or the wd of newdir's drive) as the new newdir.  */
           char *adir;
+
           if (IS_DRIVE (newdir[0]) && IS_DEVICE_SEP (newdir[1]))
             {
               drive = (unsigned char) newdir[0];
@@ -1151,7 +1195,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
             {
               ptrdiff_t newlen = strlen (newdir);
               char *tmp = alloca (newlen + strlen (nm) + 2);
-              file_name_as_directory (tmp, newdir, newlen);
+              file_name_as_directory (tmp, newdir, newlen, multibyte);
               strcat (tmp, nm);
               nm = tmp;
             }
@@ -1159,10 +1203,17 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
           if (drive)
             {
               if (!getdefdir (c_toupper (drive) - 'A' + 1, adir))
-                newdir = "/";
+                strcpy (adir, "/");
             }
           else
             getwd (adir);
+          if (multibyte)
+            {
+              Lisp_Object tem = build_string (adir);
+
+              tem = DECODE_FILE (tem);
+              memcpy (adir, SSDATA (tem), SBYTES (tem) + 1);
+            }
           newdir = adir;
         }
 
@@ -1249,7 +1300,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
             strcpy (target, newdir);
         }
       else
-        file_name_as_directory (target, newdir, length);
+        file_name_as_directory (target, newdir, length, multibyte);
     }
 
   strcat (target, nm);
@@ -1335,9 +1386,14 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
         target[1] = ':';
       }
     result = make_specified_string (target, -1, o - target, multibyte);
-    result = ENCODE_FILE (result);
-    dostounix_filename (SSDATA (result));
-    result = DECODE_FILE (result);
+    if (multibyte)
+      {
+        result = ENCODE_FILE (result);
+        dostounix_filename (SSDATA (result));
+        result = DECODE_FILE (result);
+      }
+    else
+      dostounix_filename (SSDATA (result));
 #else  /* !DOS_NT */
     result = make_specified_string (target, -1, o - target, multibyte);
 #endif /* !DOS_NT */
@@ -1619,18 +1675,24 @@ those `/' is discarded.  */)
   memcpy (nm, SDATA (filename), SBYTES (filename) + 1);
 
 #ifdef DOS_NT
-  {
-    Lisp_Object encoded_filename = ENCODE_FILE (filename);
-    Lisp_Object tem_fn;
-
-    dostounix_filename (SDATA (encoded_filename));
-    tem_fn = DECODE_FILE (encoded_filename);
-    nm = alloca (SBYTES (tem_fn) + 1);
-    memcpy (nm, SDATA (tem_fn), SBYTES (tem_fn) + 1);
-    substituted = (memcmp (nm, SDATA (filename), SBYTES (filename)) != 0);
-    if (substituted)
-      filename = tem_fn;
-  }
+  if (multibyte)
+    {
+      Lisp_Object encoded_filename = ENCODE_FILE (filename);
+      Lisp_Object tem_fn;
+
+      dostounix_filename (SDATA (encoded_filename));
+      tem_fn = DECODE_FILE (encoded_filename);
+      nm = alloca (SBYTES (tem_fn) + 1);
+      memcpy (nm, SDATA (tem_fn), SBYTES (tem_fn) + 1);
+      substituted = (memcmp (nm, SDATA (filename), SBYTES (filename)) != 0);
+      if (substituted)
+        filename = tem_fn;
+    }
+  else
+    {
+      dostounix_filename (nm);
+      substituted = (memcmp (nm, SDATA (filename), SBYTES (filename)) != 0);
+    }
 #endif
   endp = nm + SBYTES (filename);