(Fread_file_name_internal): Added brute-force

speed up for using predicate file-directory-p.

1 files changed, 30 insertions, 9 deletions

diff --git a/src/fileio.c b/src/fileio.c
index dbc5c7d9a54..2f658f9bee0 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -5911,15 +5911,36 @@ DEFUN ("read-file-name-internal", Fread_file_name_internal, Sread_file_name_inte
       if (NILP (Vread_file_name_predicate)
           || EQ (Vread_file_name_predicate, Qfile_exists_p))
         return all;
-      GCPRO3 (all, comp, specdir);
-      count = specpdl_ptr - specpdl;
-      record_unwind_protect (read_file_name_cleanup, current_buffer->directory);
-      current_buffer->directory = realdir;
-      for (comp = Qnil; CONSP (all); all = XCDR (all))
-        if (!NILP (call1 (Vread_file_name_predicate, XCAR (all))))
-          comp = Fcons (XCAR (all), comp);
-      unbind_to (count, Qnil);
-      UNGCPRO;
+
+#ifndef VMS
+      if (EQ (Vread_file_name_predicate, Qfile_directory_p))
+        {
+          /* Brute-force speed up for directory checking: 
+             Discard strings which don't end in a slash.  */
+          for (comp = Qnil; CONSP (all); all = XCDR (all))
+            {
+              Lisp_Object tem = XCAR (all);
+              int len;
+              if (STRINGP (tem) &&
+                  (len = XSTRING (tem)->size, len > 0) &&
+                  IS_DIRECTORY_SEP (XSTRING (tem)->data[len-1]))
+                comp = Fcons (tem, comp);
+            }
+        }
+      else
+#endif
+        {
+          /* Must do it the hard (and slow) way.  */
+          GCPRO3 (all, comp, specdir);
+          count = specpdl_ptr - specpdl;
+          record_unwind_protect (read_file_name_cleanup, current_buffer->directory);
+          current_buffer->directory = realdir;
+          for (comp = Qnil; CONSP (all); all = XCDR (all))
+            if (!NILP (call1 (Vread_file_name_predicate, XCAR (all))))
+              comp = Fcons (XCAR (all), comp);
+          unbind_to (count, Qnil);
+          UNGCPRO;
+        }
       return Fnreverse (comp);
     }