(file_name_completion): Install case-preserving changes from Emacs 18

for completion_ignore_case.
(completion_ignore_case): Declare.

1 files changed, 33 insertions, 3 deletions

diff --git a/src/dired.c b/src/dired.c
index ff51345183b..410729fe3dc 100644
--- a/src/dired.c
+++ b/src/dired.c
@@ -80,6 +80,7 @@ extern struct re_pattern_buffer searchbuf;
 #define lstat stat
 #endif
 
+extern int completion_ignore_case;
 extern Lisp_Object Ffind_file_name_handler ();
 
 Lisp_Object Vcompletion_ignored_extensions;
@@ -392,14 +393,43 @@ file_name_completion (file, dirname, all_flag, ver_flag)
                   matchsize = scmp(p1, p2, compare);
                   if (matchsize < 0)
                     matchsize = compare;
-                  /* If this dirname all matches,
-                     see if implicit following slash does too.  */
+                  if (completion_ignore_case)
+                    {
+                      /* If this is an exact match except for case,
+                         use it as the best match rather than one that is not
+                         an exact match.  This way, we get the case pattern
+                         of the actual match.  */
+                      if ((matchsize == len
+                           && matchsize + !!directoryp 
+                              < XSTRING (bestmatch)->size)
+                          ||
+                          /* If there is no exact match ignoring case,
+                             prefer a match that does not change the case
+                             of the input.  */
+                          (((matchsize == len)
+                            ==
+                            (matchsize + !!directoryp 
+                             == XSTRING (bestmatch)->size))
+                           /* If there is more than one exact match aside from
+                              case, and one of them is exact including case,
+                              prefer that one.  */
+                           && !bcmp (p2, XSTRING (file)->data, XSTRING (file)->size)
+                           && bcmp (p1, XSTRING (file)->data, XSTRING (file)->size)))
+                        {
+                          bestmatch = make_string (dp->d_name, len);
+                          if (directoryp)
+                            bestmatch = Ffile_name_as_directory (bestmatch);
+                        }
+                    }
+
+                  /* If this dirname all matches, see if implicit following
+                     slash does too.  */
                   if (directoryp
                       && compare == matchsize
                       && bestmatchsize > matchsize
                       && p1[matchsize] == '/')
                     matchsize++;
-                  bestmatchsize = min (matchsize, bestmatchsize);
+                  bestmatchsize = matchsize;
                 }
             }
         }