[Patch] locate --non-existing (-E): New option.

[Bas van Gompel]

Hallo,

Here is a patch which implements a ``--non-existing'' (``-E'') option
on locate. It's effect is the inverse of ``--existing'' (``-e'').

Along the way I renamed visit_exists_[no]follow to
visit_existing_[no]follow for consistency, and fixed a a few typos in
the description of --nofollow (``treat broken symbolic links /count/
as if they were exi/s/ting'').


A possible ChangeLog-entry:

2005-03-08  Bas van Gompel  <address@hidden>

        *doc/find.texi: Document locate --non-existing (-E).
        *locate/locate.1: Ditto.
        *locate/locate.c: Implement --non-existing (-E).


diff -Ndrupb curr/findutils/doc/find.texi mine2/findutils/doc/find.texi
--- findutils/doc/find.texi     2005-03-01 21:19:26.000000000 +0100
+++ findutils/doc/find.texi     2005-03-08 00:58:56.000000000 +0100
@@ -2673,17 +2673,26 @@ down the program a lot, if there are man
 The way in which broken symbolic links are treated is affected by the
 @samp{-L}, @samp{-P} and @samp{-H} options.
 
address@hidden --non-existing
address@hidden -E
+Only print out such names which currently do not exist (instead of such
+names which existed when the database was created).
+Note that this may slow down the program a lot, if there are many matches
+in the database.
+The way in which broken symbolic links are treated is affected by the
address@hidden, @samp{-P} and @samp{-H} options.
+
 @item --follow
 @itemx -L
-If testing for the existence of files (with the @samp{-e} option),
-omit broken symbolic links.  This is the default.
+If testing for the existence of files (with the @samp{-e} or @samp(-E) 
options),
+consider broken symbolic links to be non-existing.  This is the default.
 
 
 @item --nofollow
 @itemx -P
 @itemx -H
-If testing for the existence of files (with the @samp{-e} option),
-treat broken symbolic links count as if they were exiting files.  The
+If testing for the existence of files (with the @samp{-e} or @samp(-E) 
options),
+treat broken symbolic links as if they were existing files.  The
 @samp{-H} form of this option is provided purely for similarity with
 @code{find}; the use of @samp{-P} is recommended over @samp{-H}.
 
diff -Ndrupb curr/findutils/locate/locate.1 mine2/findutils/locate/locate.1
--- findutils/locate/locate.1   2005-01-29 02:27:24.000000000 +0100
+++ findutils/locate/locate.1   2005-03-08 01:01:56.000000000 +0100
@@ -3,10 +3,11 @@
 locate \- list files in databases that match a pattern
 .SH SYNOPSIS
 .B locate
-[\-d path | \-\-database=path] [\-e | \-\-existing] [\-i | \-\-ignore-case]
-[\-0 | \-\-null] [\-c | \-\-count] [\-w | \-\-wholename] [\-b | \-\-basename] 
-[\-l N | \-\-limit=N] [\-S | \-\-statistics] [\-r | \-\-regex ]
-[\-P | \-H | \-\-nofollow] [\-L | \-\-follow] [\-\-version] [\-\-help] 
pattern...
+[\-d path | \-\-database=path] [\-e | \-E | \-\-[non\-]existing] [\-i
+| \-\-ignore-case] [\-0 | \-\-null] [\-c | \-\-count] [\-w | \-\-wholename]
+|\-b | \-\-basename] [\-l N | \-\-limit=N] [\-S | \-\-statistics] [\-r
+| \-\-regex ] [\-P | \-H | \-\-nofollow] [\-L | \-\-follow] [\-\-version]
+[\-\-help] pattern...
 .SH DESCRIPTION
 This manual page
 documents the GNU version of
@@ -80,13 +81,19 @@ please note that it is possible for the 
 .B locate 
 has checked that it exists, but before you use it.
 .TP
+.I "\-E, \-\-non\-existing"
+Only print out such names that currently do not exist (instead of such names
+that existed when the database was created).
+Note that this may slow down the program a lot, if there are many matches
+in the database.
+.TP
 .I "\-L, \-\-follow"
-If testing for the existence of files (with the \-e option), omit
-broken symbolic links.   This is the default.
+If testing for the existence of files (with the \-e or \-E options),
+consider broken symbolic links to be non-existing.   This is the default.
 .TP
 .I "\-P, \-H, \-\-nofollow"
-If testing for the existence of files (with the \-e option), treat
-broken symbolic links count as if they were exiting files.  The \-H
+If testing for the existence of files (with the \-e or \-E options), treat
+broken symbolic links as if they were existing files.  The \-H
 form of this option is provided purely for similarity with
 .BR find ;
 the use of \-P is recommended over \-H.
diff -Ndrupb curr/findutils/locate/locate.c mine2/findutils/locate/locate.c
--- findutils/locate/locate.c   2005-03-05 20:11:58.000000000 +0100
+++ findutils/locate/locate.c   2005-03-06 23:38:58.000000000 +0100
@@ -331,7 +331,7 @@ visit_justprint(const char *munged_filen
 }
 
 static int
-visit_exists_follow(const char *munged_filename,
+visit_existing_follow(const char *munged_filename,
                    const char *original_filename, void *context)
 {
   struct stat st;
@@ -354,7 +354,30 @@ visit_exists_follow(const char *munged_f
 }
 
 static int
-visit_exists_nofollow(const char *munged_filename,
+visit_non_existing_follow(const char *munged_filename,
+                   const char *original_filename, void *context)
+{
+  struct stat st;
+  (void) context;
+  (void) munged_filename;
+
+  /* munged_filename has been converted in some way (to lower case,
+   * or is just the base name of the file), and original_filename has not.  
+   * Hence only original_filename is still actually the name of the file 
+   * whose existence we would need to check.
+   */
+  if (stat(original_filename, &st) == 0)
+    {
+      return VISIT_REJECTED;
+    }
+  else
+    {
+      return VISIT_CONTINUE;
+    }
+}
+
+static int
+visit_existing_nofollow(const char *munged_filename,
                      const char *original_filename, void *context)
 {
   struct stat st;
@@ -377,6 +400,29 @@ visit_exists_nofollow(const char *munged
 }
 
 static int
+visit_non_existing_nofollow(const char *munged_filename,
+                     const char *original_filename, void *context)
+{
+  struct stat st;
+  (void) context;
+  (void) munged_filename;
+
+  /* munged_filename has been converted in some way (to lower case,
+   * or is just the base name of the file), and original_filename has not.  
+   * Hence only original_filename is still actually the name of the file 
+   * whose existence we would need to check.
+   */
+  if (lstat(original_filename, &st) == 0)
+    {
+      return VISIT_REJECTED;
+    }
+  else
+    {
+      return VISIT_CONTINUE;
+    }
+}
+
+static int
 visit_substring_match_nocasefold(const char *munged_filename, const char 
*original_filename, void *context)
 {
   const char *pattern = context;
@@ -611,20 +657,20 @@ new_locate (char *pathpart,
            }
        }
 
-      /* We add visit_exists_*() as late as possible to reduce the
+      /* We add visit_existing_*() as late as possible to reduce the
        * number of stat() calls.
        */
-      if (check_existence)
-       {
-         visitfunc f;
+      if (check_existence==1)
          if (follow_symlinks)
-           f = visit_exists_follow;
+         add_visitor(visit_existing_follow, NULL);
          else
-           f = visit_exists_nofollow;
-         
-         add_visitor(f, NULL);
-       }
+         add_visitor(visit_existing_nofollow, NULL);
       
+      if (check_existence==2)
+       if (follow_symlinks)
+         add_visitor(visit_non_existing_follow, NULL);
+       else
+         add_visitor(visit_non_existing_nofollow, NULL);
 
       if (enable_print)
        add_visitor(visit_justprint, NULL);
@@ -778,7 +824,7 @@ usage (stream)
      FILE *stream;
 {
   fprintf (stream, _("\
-Usage: %s [-d path | --database=path] [-e | --existing]\n\
+Usage: %s [-d path | --database=path] [-e | -E | --[non-]existing]\n\
       [-i | --ignore-case] [-w | --wholename] [-b | --basename] \n\
       [--limit=N | -l N] [-S | --statistics] [-0 | --null] [-c | --count]\n\
       [-P | -H | --nofollow] [-L | --follow] [-m | --mmap ] [ -s | --stdio ]\n\
@@ -791,6 +837,7 @@ static struct option const longopts[] =
 {
   {"database", required_argument, NULL, 'd'},
   {"existing", no_argument, NULL, 'e'},
+  {"non-existing", no_argument, NULL, 'E'},
   {"ignore-case", no_argument, NULL, 'i'},
   {"help", no_argument, NULL, 'h'},
   {"version", no_argument, NULL, 'v'},
@@ -841,7 +888,7 @@ main (argc, argv)
 
   check_existence = 0;
 
-  while ((optc = getopt_long (argc, argv, "bcd:eil:rsm0SwHPL", longopts, (int 
*) 0)) != -1)
+  while ((optc = getopt_long (argc, argv, "bcd:eEil:rsm0SwHPL", longopts, (int 
*) 0)) != -1)
     switch (optc)
       {
       case '0':
@@ -865,6 +912,10 @@ main (argc, argv)
        check_existence = 1;
        break;
 
+      case 'E':
+       check_existence = 2;
+       break;
+
       case 'i':
        ignore_case = 1;
        break;


L8r,

Buzz.
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