Fix case-insensitive completion of non-ASCII file names

* src/dired.c (scmp): Comment on (non)applicability to
comparisons of  non-ASCII strings case-insensitively.
(file_name_completion): Decode early the file names read from
the directory, and use the decoded names for comparison when
letter-case should be ignored.  (Bug#11339)

diff --git a/src/dired.c b/src/dired.c
index 3768b6dbb7cc912763b8fe1ea62015e3222eb7a4..0e1c88f03ce037581e185840759810f1d705973b 100644 (file)
--- a/src/dired.c
+++ b/src/dired.c
@@ -481,18 +481,32 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
   record_unwind_protect_ptr (directory_files_internal_unwind, d);
 
   /* Loop reading directory entries.  */
+  Lisp_Object zero = make_fixnum (0);
+  ptrdiff_t enc_file_len = SCHARS (encoded_file);
+  Lisp_Object file_len = make_fixnum (SCHARS (file));
   for (struct dirent *dp; (dp = read_dirent (d, dirname)); )
     {
       ptrdiff_t len = dirent_namelen (dp);
       bool canexclude = 0;
 
       maybe_quit ();
-      if (len < SCHARS (encoded_file)
-         || (scmp (dp->d_name, SSDATA (encoded_file),
-                   SCHARS (encoded_file))
-             >= 0))
+
+      if (len < enc_file_len
+         /* scmp cannot reliably compare non-ASCII strings while
+            ignoring letter-case.  */
+         || (!completion_ignore_case
+             && scmp (dp->d_name, SSDATA (encoded_file), enc_file_len) >= 0))
        continue;
 
+      name = make_unibyte_string (dp->d_name, len);
+      name = DECODE_FILE (name);
+      ptrdiff_t name_blen = SBYTES (name), name_len = SCHARS (name);
+      if (completion_ignore_case
+         && !EQ (Fcompare_strings (name, zero, file_len, file, zero, file_len,
+                                   Qt),
+                 Qt))
+           continue;
+
       switch (dirent_type (dp))
        {
        case DT_DIR:
@@ -515,6 +529,7 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
       if (!all_flag)
        {
          ptrdiff_t skip;
+         Lisp_Object cmp_len = make_fixnum (name_len);
 
 #if 0 /* FIXME: The `scmp' call compares an encoded and a decoded string. */
          /* If this entry matches the current bestmatch, the only
@@ -538,7 +553,7 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
                 actually in the way in a directory with only one file.  */
              if (TRIVIAL_DIRECTORY_ENTRY (dp->d_name))
                canexclude = 1;
-             else if (len > SCHARS (encoded_file))
+             else if (len > enc_file_len)
                /* Ignore directories if they match an element of
                   completion-ignored-extensions which ends in a slash.  */
                for (tem = Vcompletion_ignored_extensions;
@@ -550,21 +565,31 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
                    elt = XCAR (tem);
                    if (!STRINGP (elt))
                      continue;
-                   /* Need to encode ELT, since scmp compares unibyte
-                      strings only.  */
-                   elt = ENCODE_FILE (elt);
-                   elt_len = SCHARS (elt) - 1; /* -1 for trailing / */
+                   elt_len = SBYTES (elt) - 1; /* -1 for trailing / */
                    if (elt_len <= 0)
                      continue;
                    p1 = SSDATA (elt);
                    if (p1[elt_len] != '/')
                      continue;
-                   skip = len - elt_len;
+                   skip = name_blen - elt_len;
                    if (skip < 0)
                      continue;
 
-                   if (scmp (dp->d_name + skip, p1, elt_len) >= 0)
+                   if (!completion_ignore_case
+                       && scmp (SSDATA (name) + skip, p1, elt_len) >= 0)
                      continue;
+                   if (completion_ignore_case)
+                     {
+                       elt_len = SCHARS (elt) - 1;
+                       skip = name_len - elt_len;
+                       cmp_len = make_fixnum (elt_len);
+                       if (skip < 0
+                           || !EQ (Fcompare_strings (name, make_fixnum (skip),
+                                                     cmp_len,
+                                                     elt, zero, cmp_len, Qt),
+                                   Qt))
+                         continue;
+                     }
                    break;
                  }
            }
@@ -572,22 +597,33 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
            {
              /* Compare extensions-to-be-ignored against end of this file name */
              /* if name is not an exact match against specified string */
-             if (len > SCHARS (encoded_file))
+             if (len > enc_file_len)
                /* and exit this for loop if a match is found */
                for (tem = Vcompletion_ignored_extensions;
                     CONSP (tem); tem = XCDR (tem))
                  {
                    elt = XCAR (tem);
                    if (!STRINGP (elt)) continue;
-                   /* Need to encode ELT, since scmp compares unibyte
-                      strings only.  */
-                   elt = ENCODE_FILE (elt);
-                   skip = len - SCHARS (elt);
+                   ptrdiff_t elt_len = SBYTES (elt);
+                   skip = len - elt_len;
                    if (skip < 0) continue;
 
-                   if (scmp (dp->d_name + skip, SSDATA (elt), SCHARS (elt))
-                       >= 0)
+                   if (!completion_ignore_case
+                       && (scmp (SSDATA (name) + skip, SSDATA (elt), elt_len)
+                           >= 0))
                      continue;
+                   if (completion_ignore_case)
+                     {
+                       elt_len = SCHARS (elt);
+                       skip = name_len - elt_len;
+                       cmp_len = make_fixnum (elt_len);
+                       if (skip < 0
+                           || !EQ (Fcompare_strings (name, make_fixnum (skip),
+                                                     cmp_len,
+                                                     elt, zero, cmp_len, Qt),
+                                   Qt))
+                         continue;
+                     }
                    break;
                  }
            }
@@ -611,24 +647,18 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
              matchcount = 0;
            }
        }
-      /* FIXME: If we move this `decode' earlier we can eliminate
-        the repeated ENCODE_FILE on Vcompletion_ignored_extensions.  */
-      name = make_unibyte_string (dp->d_name, len);
-      name = DECODE_FILE (name);
 
-      {
-       Lisp_Object regexps, table = (completion_ignore_case
-                                     ? Vascii_canon_table : Qnil);
+      Lisp_Object regexps, table = (completion_ignore_case
+                                   ? Vascii_canon_table : Qnil);
 
-       /* Ignore this element if it fails to match all the regexps.  */
-       for (regexps = Vcompletion_regexp_list; CONSP (regexps);
-            regexps = XCDR (regexps))
-         if (fast_string_match_internal (XCAR (regexps), name, table) < 0)
-           break;
+      /* Ignore this element if it fails to match all the regexps.  */
+      for (regexps = Vcompletion_regexp_list; CONSP (regexps);
+          regexps = XCDR (regexps))
+       if (fast_string_match_internal (XCAR (regexps), name, table) < 0)
+         break;
 
-       if (CONSP (regexps))
-         continue;
-      }
+      if (CONSP (regexps))
+       continue;
 
       /* This is a possible completion */
       if (directoryp)
@@ -642,8 +672,6 @@ file_name_completion (Lisp_Object file, Lisp_Object dirname, bool all_flag,
       /* Reject entries where the encoded strings match, but the
          decoded don't.  For example, "a" should not match "a-ring" on
          file systems that store decomposed characters. */
-      Lisp_Object zero = make_fixnum (0);
-
       if (check_decoded && SCHARS (file) <= SCHARS (name))
        {
          /* FIXME: This is a copy of the code below.  */
@@ -757,6 +785,9 @@ scmp (const char *s1, const char *s2, ptrdiff_t len)
 
   if (completion_ignore_case)
     {
+      /* WARNING: This only works for pure ASCII strings, as we
+        compare bytes, not characters!  Use Fcompare_strings for
+        comparing non-ASCII strings case-insensitively.  */
       while (l
             && (downcase ((unsigned char) *s1++)
                 == downcase ((unsigned char) *s2++)))