| 1 | eval '(exit $?0)' && eval 'exec perl -wST "$0" ${1+"$@"}'
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| 2 | & eval 'exec perl -wST "$0" $argv:q'
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| 3 | if 0;
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| 4 | # Detect instances of "if (p) free (p);".
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| 5 | # Likewise "if (p != 0)", "if (0 != p)", or with NULL; and with braces.
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| 6 |
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| 7 | my $VERSION = '2012-01-06 07:23'; # UTC
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| 8 | # The definition above must lie within the first 8 lines in order
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| 9 | # for the Emacs time-stamp write hook (at end) to update it.
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| 10 | # If you change this file with Emacs, please let the write hook
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| 11 | # do its job. Otherwise, update this string manually.
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| 12 |
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| 13 | # Copyright (C) 2008-2012 Free Software Foundation, Inc.
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| 14 |
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| 15 | # This program is free software: you can redistribute it and/or modify
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| 16 | # it under the terms of the GNU General Public License as published by
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| 17 | # the Free Software Foundation, either version 3 of the License, or
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| 18 | # (at your option) any later version.
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| 19 |
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| 20 | # This program is distributed in the hope that it will be useful,
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| 21 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 22 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 23 | # GNU General Public License for more details.
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| 24 |
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| 25 | # You should have received a copy of the GNU General Public License
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| 26 | # along with this program. If not, see <http://www.gnu.org/licenses/>.
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| 27 |
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| 28 | # Written by Jim Meyering
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| 29 |
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| 30 | use strict;
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| 31 | use warnings;
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| 32 | use Getopt::Long;
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| 33 |
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| 34 | (my $ME = $0) =~ s|.*/||;
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| 35 |
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| 36 | # use File::Coda; # http://meyering.net/code/Coda/
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| 37 | END {
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| 38 | defined fileno STDOUT or return;
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| 39 | close STDOUT and return;
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| 40 | warn "$ME: failed to close standard output: $!\n";
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| 41 | $? ||= 1;
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| 42 | }
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| 43 |
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| 44 | sub usage ($)
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| 45 | {
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| 46 | my ($exit_code) = @_;
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| 47 | my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR);
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| 48 | if ($exit_code != 0)
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| 49 | {
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| 50 | print $STREAM "Try '$ME --help' for more information.\n";
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| 51 | }
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| 52 | else
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| 53 | {
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| 54 | print $STREAM <<EOF;
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| 55 | Usage: $ME [OPTIONS] FILE...
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| 56 |
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| 57 | Detect any instance in FILE of a useless "if" test before a free call, e.g.,
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| 58 | "if (p) free (p);". Any such test may be safely removed without affecting
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| 59 | the semantics of the C code in FILE. Use --name=FOO --name=BAR to also
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| 60 | detect free-like functions named FOO and BAR.
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| 61 |
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| 62 | OPTIONS:
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| 63 |
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| 64 | --list print only the name of each matching FILE (\\0-terminated)
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| 65 | --name=N add name N to the list of \'free\'-like functions to detect;
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| 66 | may be repeated
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| 67 |
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| 68 | --help display this help and exit
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| 69 | --version output version information and exit
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| 70 |
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| 71 | Exit status:
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| 72 |
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| 73 | 0 one or more matches
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| 74 | 1 no match
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| 75 | 2 an error
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| 76 |
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| 77 | EXAMPLE:
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| 78 |
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| 79 | For example, this command prints all removable "if" tests before "free"
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| 80 | and "kfree" calls in the linux kernel sources:
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| 81 |
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| 82 | git ls-files -z |xargs -0 $ME --name=kfree
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| 83 |
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| 84 | EOF
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| 85 | }
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| 86 | exit $exit_code;
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| 87 | }
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| 88 |
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| 89 | sub is_NULL ($)
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| 90 | {
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| 91 | my ($expr) = @_;
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| 92 | return ($expr eq 'NULL' || $expr eq '0');
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| 93 | }
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| 94 |
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| 95 | {
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| 96 | sub EXIT_MATCH {0}
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| 97 | sub EXIT_NO_MATCH {1}
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| 98 | sub EXIT_ERROR {2}
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| 99 | my $err = EXIT_NO_MATCH;
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| 100 |
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| 101 | my $list;
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| 102 | my @name = qw(free);
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| 103 | GetOptions
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| 104 | (
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| 105 | help => sub { usage 0 },
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| 106 | version => sub { print "$ME version $VERSION\n"; exit },
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| 107 | list => \$list,
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| 108 | 'name=s@' => \@name,
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| 109 | ) or usage 1;
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| 110 |
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| 111 | # Make sure we have the right number of non-option arguments.
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| 112 | # Always tell the user why we fail.
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| 113 | @ARGV < 1
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| 114 | and (warn "$ME: missing FILE argument\n"), usage EXIT_ERROR;
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| 115 |
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| 116 | my $or = join '|', @name;
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| 117 | my $regexp = qr/(?:$or)/;
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| 118 |
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| 119 | # Set the input record separator.
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| 120 | # Note: this makes it impractical to print line numbers.
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| 121 | $/ = '"';
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| 122 |
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| 123 | my $found_match = 0;
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| 124 | FILE:
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| 125 | foreach my $file (@ARGV)
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| 126 | {
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| 127 | open FH, '<', $file
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| 128 | or (warn "$ME: can't open '$file' for reading: $!\n"),
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| 129 | $err = EXIT_ERROR, next;
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| 130 | while (defined (my $line = <FH>))
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| 131 | {
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| 132 | while ($line =~
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| 133 | /\b(if\s*\(\s*([^)]+?)(?:\s*!=\s*([^)]+?))?\s*\)
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| 134 | # 1 2 3
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| 135 | (?: \s*$regexp\s*\((?:\s*\([^)]+\))?\s*([^)]+)\)\s*;|
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| 136 | \s*\{\s*$regexp\s*\((?:\s*\([^)]+\))?\s*([^)]+)\)\s*;\s*\}))/sxg)
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| 137 | {
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| 138 | my $all = $1;
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| 139 | my ($lhs, $rhs) = ($2, $3);
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| 140 | my ($free_opnd, $braced_free_opnd) = ($4, $5);
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| 141 | my $non_NULL;
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| 142 | if (!defined $rhs) { $non_NULL = $lhs }
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| 143 | elsif (is_NULL $rhs) { $non_NULL = $lhs }
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| 144 | elsif (is_NULL $lhs) { $non_NULL = $rhs }
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| 145 | else { next }
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| 146 |
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| 147 | # Compare the non-NULL part of the "if" expression and the
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| 148 | # free'd expression, without regard to white space.
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| 149 | $non_NULL =~ tr/ \t//d;
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| 150 | my $e2 = defined $free_opnd ? $free_opnd : $braced_free_opnd;
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| 151 | $e2 =~ tr/ \t//d;
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| 152 | if ($non_NULL eq $e2)
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| 153 | {
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| 154 | $found_match = 1;
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| 155 | $list
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| 156 | and (print "$file\0"), next FILE;
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| 157 | print "$file: $all\n";
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| 158 | }
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| 159 | }
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| 160 | }
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| 161 | }
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| 162 | continue
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| 163 | {
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| 164 | close FH;
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| 165 | }
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| 166 |
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| 167 | $found_match && $err == EXIT_NO_MATCH
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| 168 | and $err = EXIT_MATCH;
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| 169 |
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| 170 | exit $err;
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| 171 | }
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| 172 |
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| 173 | my $foo = <<'EOF';
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| 174 | # The above is to *find* them.
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| 175 | # This adjusts them, removing the unnecessary "if (p)" part.
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| 176 |
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| 177 | # FIXME: do something like this as an option (doesn't do braces):
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| 178 | free=xfree
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| 179 | git grep -l -z "$free *(" \
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| 180 | | xargs -0 useless-if-before-free -l --name="$free" \
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| 181 | | xargs -0 perl -0x3b -pi -e \
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| 182 | 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*(?:0|NULL))?\s*\)\s+('"$free"'\s*\((?:\s*\([^)]+\))?\s*\1\s*\)\s*;)/$2/s'
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| 183 |
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| 184 | # Use the following to remove redundant uses of kfree inside braces.
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| 185 | # Note that -0777 puts perl in slurp-whole-file mode;
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| 186 | # but we have plenty of memory, these days...
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| 187 | free=kfree
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| 188 | git grep -l -z "$free *(" \
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| 189 | | xargs -0 useless-if-before-free -l --name="$free" \
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| 190 | | xargs -0 perl -0777 -pi -e \
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| 191 | 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*(?:0|NULL))?\s*\)\s*\{\s*('"$free"'\s*\((?:\s*\([^)]+\))?\s*\1\s*\);)\s*\}[^\n]*$/$2/gms'
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| 192 |
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| 193 | Be careful that the result of the above transformation is valid.
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| 194 | If the matched string is followed by "else", then obviously, it won't be.
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| 195 |
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| 196 | When modifying files, refuse to process anything other than a regular file.
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| 197 | EOF
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| 198 |
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| 199 | ## Local Variables:
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| 200 | ## mode: perl
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| 201 | ## indent-tabs-mode: nil
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| 202 | ## eval: (add-hook 'write-file-hooks 'time-stamp)
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| 203 | ## time-stamp-start: "my $VERSION = '"
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| 204 | ## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
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| 205 | ## time-stamp-time-zone: "UTC"
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| 206 | ## time-stamp-end: "'; # UTC"
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| 207 | ## End:
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