#!/usr/bin/perl
#
# NAME
#    supplant - replace files with authoritative version.
#
# SYNOPSIS
#    supplant file... [dir]...
#
# DESCRIPTION
#   This program scans the named directories ("."  by  default)  looking  for
#   files  named  the  same as the "file" in $ARGV[1]; if any are found, they
#   are replaced by the named file. The replacing is done via Lc, so:  (1) ln
#   will  be  used if possible, and cp if ln fails; and (2) The old file will
#   be renamed to a backup copy.
#
#   You must give at least one file.  If you list more than one file, we will
#   do  each  of  them in turn, searching all the listed directories for each
#   file, and doing a supplant for each.
#
#   This program shows its actions via the messages:
#     ++++> file        successful supplant.
#     ----> file        didn't supplant (already linked).
#   Note that only "plain files" are noticed; directories are not supplanted.
#
# BUGS:
#   For different file systems, supplanting will always be  done.   We  might
#   insert  a  check  for  this situation; doing it right will then require a
#   full compare of the files.
#
# STATUS:
#   0 if at least one file supplanted; 1 if not.
#
# AUTHOR:
#   John Chambers <jc@trillian.mit.edu>
#
# PERMISSIONS:
#   You may use this program freely as long as you don't claim that you wrote
#   it, and you agree to pass it along to anyone else who asks for it. If you
#   come up with any useful additions, you might email me a copy.

($me = $0) =~ s".*/"";
$V = $ENV{"V_$me"} || $ENV{"D_$me"} || 1;
$| = 1;

for $x (@ARGV) {	# Run thru the args, building @file and @dir lists.
	if ( -d $x) {
		push @dir, $x unless -l $x;
	} elsif ( -f $x) {
		push @file, $x unless -l $x;
	} else {
		print STDERR "$0: \"$x\" does not exist.\n";
	}
}
@dir = ('.') if !@dir;
die "Usage: $0 file... [dir]...\n" if !@file;

for $F (@file) {	# Run thru the file names.
	($f = $F) =~ s".*/"";	# Remove directories from filename.
	if (($fdev,$fino,$fm,$fnl,$fu,$fg,$frd,$fsize) = stat($F)) {
		print "Supplanting $f in @dir ...\n";
		for $d (@dir) {	# Run thru the directory list recursively.
			&supplant($f,$d);
		}
	} else {
		print STDERR "$0: Can't stat \"$F\"\n";
	}
}
exit ($files == 0);	# Success if at least one file supplanted.

sub supplant {
	local($f,$d) = @_;
#	printf STDERR "Dir : \"$d\"\n";
	if (opendir(D,$d)) {
		local(@list) = grep(!/\.\.?$/, readdir(D));
#		printf STDERR "Close \"$d\"\n";
		closedir(D);
		$p = "$d/$f";
		$p =~ s/^\.\///;
		if (-f $p) {	# Only look at "files", not directories.
#			printf STDERR "File: \"$p\"\n";
			if (($pdev,$pino,$pm,$pnl,$pu,$pg,$prd,$psize) = stat($p)) {
				if ($pdev == $fdev && $pino == $fino) {
					printf STDERR "----> \"$p\"\n";
				} else {
					printf STDERR "++++> \"$p\"\n";
					system "Lc '$F' '$d/$f'";
					++$files;
				}
			} else {
				printf STDERR "$0: Can't stat \"$f\"\n";
			}
		} elsif (-l $p) {
			printf STDERR "(lnk) \"$p\"\n";
		} elsif (-d $p) {
			printf STDERR "(dir) \"$p\"\n";
		}
		for $x (@list) {
#			printf STDERR "Try : \"$d/$x\"\n";
			next if ($x eq "." || $x eq "..");
			if (-d "$d/$x") {
#				printf STDERR "Sub : \"$d/$x\"\n";
				&supplant($f,"$d/$x") unless -l "$d/$x";
			}
		}
	} else {
		printf STDERR "$0: Can't access \"$d\"\n";
	}
}