Pull useless-if-before-free from gnulib, and update.

* bootstrap (gnulib_tool): Add useless-if-before-free to
the list of modules.
* build-aux/useless-if-before-free: Update from gnulib.
* gnulib/lib/vasnprintf.c: Work around a bug in HPUX 10.20.
* gnulib/m4/vasnprintf.m4: Likewise.

1 files changed, 75 insertions, 21 deletions

diff --git a/build-aux/useless-if-before-free b/build-aux/useless-if-before-free
index 57040a3d8..eb1848378 100755
--- a/build-aux/useless-if-before-free
+++ b/build-aux/useless-if-before-free
@@ -1,24 +1,43 @@
 #!/usr/bin/perl -T
 # Detect instances of "if (p) free (p);".
-# Likewise for "if (p != NULL) free (p);".
+# Likewise for "if (p != NULL) free (p);".  And with braces.
 
-my $VERSION = '2008-02-04 22:25'; # UTC
+my $VERSION = '2008-02-11 08:08'; # UTC
 # The definition above must lie within the first 8 lines in order
 # for the Emacs time-stamp write hook (at end) to update it.
 # If you change this file with Emacs, please let the write hook
 # do its job.  Otherwise, update this string manually.
 
-# Exit status is like grep: 0 for no match. 1 for any number.
-# Note: giving line numbers isn't practical, since I've reset the
-# input record separator.
+# Copyright (C) 2008 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Written by Jim Meyering
+
 use strict;
 use warnings;
 use Getopt::Long;
 
 (my $ME = $0) =~ s|.*/||;
 
-my $debug = 0;
-my $verbose = 0;
+# use File::Coda; # http://meyering.net/code/Coda/
+END {
+  defined fileno STDOUT or return;
+  close STDOUT and return;
+  warn "$ME: failed to close standard output: $!\n";
+  $? ||= 1;
+}
 
 sub usage ($)
 {
@@ -33,18 +52,32 @@ sub usage ($)
       print $STREAM <<EOF;
 Usage: $ME [OPTIONS] FILE...
 
+Detect any instance in FILE of a useless "if" test before a free call, e.g.,
+"if (p) free (p);".  Any such test may be safely removed without affecting
+the semantics of the C code in FILE.  Use --name=FOO --name=BAR to also
+detect free-like functions named FOO and BAR.
+
 OPTIONS:
 
+   --list       print only the name of each matching FILE (\0-terminated)
    --name=N     add name N to the list of `free'-like functions to detect;
                   may be repeated
 
    --help       display this help and exit
    --version    output version information and exit
-   --verbose    generate verbose output
+
+Exit status:
+
+  0   no match
+  1   one or more matches
+  2   an error
 
 EXAMPLE:
 
-    git ls-files -z |xargs -0 $ME
+For example, this command prints all removable "if" tests before "free"
+and "kfree" calls in the linux kernel sources:
+
+    git ls-files -z |xargs -0 $ME --name=kfree
 
 EOF
     }
@@ -52,32 +85,40 @@ EOF
 }
 
 {
+  sub EXIT_MATCH {0}
+  sub EXIT_NO_MATCH {1}
+  sub EXIT_ERROR {2}
+  my $err = EXIT_NO_MATCH;
+
+  my $list;
   my @name = qw(free);
   GetOptions
     (
-     debug => \$debug,
-     verbose => \$verbose,
      help => sub { usage 0 },
      version => sub { print "$ME version $VERSION\n"; exit },
+     list => \$list,
      'name=s@' => \@name,
     ) or usage 1;
 
   # Make sure we have the right number of non-option arguments.
   # Always tell the user why we fail.
   @ARGV < 1
-    and (warn "$ME: missing FILE argument\n"), usage 1;
+    and (warn "$ME: missing FILE argument\n"), usage EXIT_ERROR;
 
   my $or = join '|', @name;
   my $regexp = qr/(?:$or)/;
 
   # Set the input record separator.
+  # Note: this makes it impractical to print line numbers.
   $/ = '"';
 
   my $found_match = 0;
+ FILE:
   foreach my $file (@ARGV)
     {
       open FH, '<', $file
-        or die "$ME: can't open `$file' for reading: $!\n";
+        or (warn "$ME: can't open `$file' for reading: $!\n"),
+          $err = EXIT_ERROR, next;
       while (defined (my $line = <FH>))
         {
           if ($line =~
@@ -85,27 +126,40 @@ EOF
                (?:   \s*$regexp\s*\(\s*\2\s*\)|
                 \s*\{\s*$regexp\s*\(\s*\2\s*\)\s*;\s*\}))/sx)
             {
-              print "$file: $1\n";
               $found_match = 1;
+              $list
+                and (print "$file\0"), next FILE;
+              print "$file: $1\n";
             }
         }
+    }
+  continue
+    {
       close FH;
     }
-  exit !$found_match;
+
+  $found_match && $err == EXIT_NO_MATCH
+    and $err = EXIT_MATCH;
+
+  exit $err;
 }
 
 my $foo = <<'EOF';
 # The above is to *find* them.
 # This adjusts them, removing the unnecessary "if (p)" part.
 
-# FIXME: do something like this as an option.
-git ls-files -z --exclude=$ME |xargs -0 \
-perl -0x3b -pi -e 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+((?:sexpr_)?free\s*\(\s*\1\s*\))/$2/s'
+# FIXME: do something like this as an option (doesn't do braces):
+git ls-files -z |xargs -0 \
+perl -0x3b -pi -e 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+(k?free\s*\(\s*\1\s*\))/$2/s'
 
-When modifying files, refuse to process anything other than a regular file.
+useless-if-before-free -l $(lid -knone free) | xargs -0 \
+  perl -0x3b -pi -e \
+   's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+(free\s*\(\s*\1\s*\))/$2/s'
 
-# Or this one-liner to detect them:
-git ls-files -z |xargs -0 perl -00 -ne '/\b(if\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)(?:\s*(?:sexpr_)?free\s*\(\s*\2\s*\)|\s*\{\s*(?:sexpr_)?free\s*\(\s*\2\s*\)\s*;\s*\}))/sx and print "$1\n"'
+Be careful that the result of the above transformation is valid.
+If the matched string is followed by "else", then obviously, it won't be.
+
+When modifying files, refuse to process anything other than a regular file.
 EOF
 
 ## Local Variables: