Re: Emacs 23 Mac port

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

>>>>> On Wed, 28 Apr 2010 09:57:15 +0100, Leo <sdl.web@gmail.com> said:

> I sometimes run into alias files in dired and emacs treat them like
> a normal file. Do you think this can be fixed? Thank you.

Perhaps do-applescript can be used for resolving an alias file like:

(do-applescript "tell application \"Finder\" to get POSIX path of (the
 original item of (the POSIX file \"SOME_ALIAS_FILE\" as alias) as alias)")

but this requires quoting and unquoting file name strings.

I'll add `mac-file-alias-p', which is supposed to be parallel to
`file-symlink-p', to the next release.  This would enable you to
advise some dired function, I guess.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp

=== modified file 'src/mac.c'
*** src/mac.c	2010-04-15 00:55:57 +0000
--- src/mac.c	2010-04-29 03:18:20 +0000
***************
*** 1826,1831 ****
--- 1826,1833 ----
  }
  
  \f
+ Lisp_Object Qmac_file_alias_p;
+ 
  void
  initialize_applescript ()
  {
***************
*** 2044,2049 ****
--- 2046,2103 ----
    return Qt;
  }
  
+ DEFUN ("mac-file-alias-p", Fmac_file_alias_p, Smac_file_alias_p, 1, 1, 0,
+        doc: /* Return non-nil if file FILENAME is the name of an alias file.
+ The value is the file referred to by the alias file, as a string.
+ Otherwise it returns nil.
+ 
+ This function returns t when given the name of an alias file
+ containing a unresolvable alias.  */)
+      (filename)
+      Lisp_Object filename;
+ {
+   OSStatus err;
+   Lisp_Object handler, result = Qnil;
+   FSRef fref;
+ 
+   CHECK_STRING (filename);
+   filename = Fexpand_file_name (filename, Qnil);
+ 
+   /* If the file name has special constructs in it,
+      call the corresponding file handler.  */
+   handler = Ffind_file_name_handler (filename, Qmac_file_alias_p);
+   if (!NILP (handler))
+     return call2 (handler, Qmac_file_alias_p, filename);
+ 
+   BLOCK_INPUT;
+   err = FSPathMakeRef (SDATA (ENCODE_FILE (filename)), &fref, NULL);
+   if (err == noErr)
+     {
+       Boolean alias_p = false, folder_p;
+ 
+       err = FSResolveAliasFileWithMountFlags (&fref, false,
+ 					      &folder_p, &alias_p,
+ 					      kResolveAliasFileNoUI);
+       if (err != noErr)
+ 	result = Qt;
+       else if (alias_p)
+ 	{
+ 	  char buf[MAXPATHLEN];
+ 
+ 	  err = FSRefMakePath (&fref, buf, sizeof (buf));
+ 	  if (err == noErr)
+ 	    {
+ 	      result = make_unibyte_string (buf, strlen (buf));
+ 	      if (buf[0] == '/' && index (buf, ':'))
+ 		result = concat2 (build_string ("/:"), result);
+ 	      result = DECODE_FILE (result);
+ 	    }
+ 	}
+     }
+   UNBLOCK_INPUT;
+ 
+   return result;
+ }
  
  /* Moving files to the system recycle bin.
     Used by `move-file-to-trash' instead of the default moving to ~/.Trash  */
***************
*** 3790,3795 ****
--- 3844,3852 ----
    Qdictionary = intern_c_string ("dictionary");	staticpro (&Qdictionary);
    Qdescription = intern_c_string ("description"); staticpro (&Qdescription);
  
+   Qmac_file_alias_p = intern_c_string ("mac-file-alias-p");
+   staticpro (&Qmac_file_alias_p);
+ 
    Qxml = intern_c_string ("xml");
    staticpro (&Qxml);
  
***************
*** 3823,3828 ****
--- 3880,3886 ----
    defsubr (&Smac_set_file_type);
    defsubr (&Smac_get_file_creator);
    defsubr (&Smac_get_file_type);
+   defsubr (&Smac_file_alias_p);
    defsubr (&Ssystem_move_file_to_trash);
    defsubr (&Sdo_applescript);