#! /usr/bin/perl
#
# trimrcs -- clean up trailing junk in RCS files
#
# Usage:  trimrcs [-n] [-v] file [ file ...]
#
# Options:
#
#    -n   no-op (don't modify any files) 
#    -v   verbose
#
# The simplest usage is:  trimrcs -v RCS/*,v
#
# Earlier versions of RCS (up throught 5.7) would sometimes leave
# trailing junk in a file when revisions were deleted with "rcs -o".
# This junk was silently ignored until RCS 5.8, which does more
# thorough validation, and will die with a warning like:
#
#   co: RCS/file.txt,v:783: junk at end of file: '1'
#
# This script will clean up trailing junk in RCS files.
# The original file is saved as "file,v.orig".
# This script requires RCS v5.8.
#
# $Id: trimrcs 5492 2013-01-17 21:20:04Z wjones $
# $URL: https://engsvnhost.tc.fluke.com/repos/sesg/linux/branches/SUSE_12_2/local/bin/trimrcs $

use strict;
use warnings;
use Getopt::Std;
use subs qw( trim_junk fatal usage );

$ENV{PATH} = '/bin:/usr/bin';

my %opts;

getopts( 'hnv', \%opts );
my $noop    = $opts{n} || 0;
my $verbose = $opts{v} || 0;

my $version = `rlog -V 2>&1`;
fatal "requires RCS version 5.8"
     unless $version =~ /^rlog \(GNU RCS\) 5.8/;

if ( ! @ARGV || $opts{h} ) {
    usage;
    exit;
}

foreach my $name ( @ARGV ) {
    my $rlog = `rlog -R $name 2>&1`;
    if ( $? == 0 ) {
        print "$name: OK\n" if $verbose;
    }
    elsif ( $rlog =~ m{^rlog: (.*,v):(\d+): junk at end of file:}m ) {
        printf "%s: truncate at line %d\n", $1, $2 if $verbose;
        trim_junk( $1, $2-1 ) unless $noop;
    }
    else {
        fatal $rlog;
    }
}

sub trim_junk {
    my ( $file, $last_line ) = @_;
    my $new  = "$file.new";
    my $orig = "$file.orig";
    fatal "$orig already exists" if -e $orig;
    open( FILE, '<', $file ) || fatal "cannot open $file.";
    open( NEW,  '>', $new  ) || fatal "cannot create $new.";
    while ( <FILE> ) {
        print NEW;
        last if $. == $last_line;
    }
    close FILE;
    close NEW;
    rename( $file, $orig ) || fatal "cannot rename $file.";
    rename( $new,  $file ) || fatal "cannot rename $new.";
    my $perm = (stat $orig)[2] & 07777;
    chmod $perm, $file;
}

sub fatal {
    $_ = $0;
    s|.*/||;
    die "$_: @_\n";
}

sub usage {
     print <<"USAGE";
Usage: trimrcs [-h] [-n] [-v] file [file ...]

Options:
    -h  help (this message)
    -n  no-op
    -v  verbose

USAGE
}