Index: cvsdo.pl
===================================================================
RCS file: /usr/local/cvs/cvsutils/cvsdo.pl,v
retrieving revision 1.3
diff -u -r1.3 cvsdo.pl
--- cvsdo.pl
+++ cvsdo.pl
@@ -8,7 +8,7 @@
 use Getopt::Long;
 use strict;
 
-use vars qw($force_mode $entries_tmp);
+use vars qw($force_mode $entries_tmp $cvs_root $path);
 
 # Print message and exit (like "die", but without raising an exception).
 # Newline is added at the end.
@@ -118,7 +118,14 @@
 sub handle_added ($)
 {
 	my $file = shift(@_);
-	open(DIFFOUT, "diff -u -L /dev/null -L $file /dev/null $file |") ||
+	my $nullfile;
+	if ($^O =~ m!win|os/2!i) {
+		$nullfile = 'nul';
+	} else {
+		$nullfile = '/dev/null';
+	}
+	my $diff_opts = $ENV{'DIFFCMD'}||'-u';
+	open(DIFFOUT, "diff $diff_opts -L $nullfile -L $file $nullfile $file |") ||
 		error ("Cannot read output of diff: $!");
 	unix_print ("Index: $file");
 	while (<DIFFOUT>) {
@@ -161,10 +168,12 @@
 	# Lookup the original timestamp in CVS/Entries.
 	open (ENTRIES, "< ${dir}CVS/Entries")
 		|| error ("couldn't open ${dir}CVS/Entries: $!");
+	my $cvs_rev;
 	my $date_str;
 	while (<ENTRIES>) {
-		if ( m{^/$short_file/[^/]*/([^/]+)/} ) {
-			$date_str = $1;
+		if ( m{^/$short_file/([^/]*)/([^/]+)/} ) {
+			$cvs_rev = $1;
+			$date_str = $2;
 			last;
 		}
 	}
@@ -173,6 +182,7 @@
 	}
 	close (ENTRIES);
 
+        $date_str = 'Unk Jan 01 01:01:01 1970' if $date_str eq 'Result of merge';
 	unless ($date_str =~ m{^(...) (...) (..) (..):(..):(..) (....)$}) {
 		error ("Invalid timestamp for $file: $date_str");
 	}
@@ -195,11 +205,21 @@
 	closedir (DIR);
 
 	unless (defined $backup_file) {
-		warning ("Backup file for $file not found");
-		return;
+		my $cvs_rev2 = $cvs_rev; $cvs_rev2 =~ tr/\./_/;
+		if ($file eq $short_file) {
+			$backup_file = ".#$file.$cvs_rev2";
+		} else {
+			$backup_file = "$dir.#$short_file.$cvs_rev2";
+		}
+		if (-f $backup_file) {
+			warning ("Using $backup_file for $file");
+		} else {
+			warning ("Backup file for $file not found; retrieving from cvs as $backup_file");
+			`cvs up -p -r $cvs_rev $file 2>&1 > $backup_file`;
+		}
 	}
 
-	my $diff_opts = "-u";
+	my $diff_opts = $ENV{'DIFFCMD'}||'-u';
 	if ($short_file eq "ChangeLog") {
 		$diff_opts = "-u1";
 	}
@@ -208,6 +228,11 @@
 	     "diff $diff_opts -L $file -L $file $backup_file $file |") ||
 		error ("Cannot read output of diff: $!");
 	unix_print ("Index: $file");
+	unix_print ("===================================================================");
+	unix_print ("RCS file: $cvs_root/$path/$file,v");
+	unix_print ("retrieving revision $cvs_rev");
+	unix_print ("diff $diff_opts -r$cvs_rev $file");
+
 	while (<DIFFOUT>) {
 		unix_print ($_);
 	}
@@ -216,21 +241,41 @@
 # Handle `diff' command.
 sub handle_diff ()
 {
+	my %file_list;
 	if ($#ARGV >= 0)
 	{
-		usage ();
+		usage () if $ARGV[0] eq '--help';
+		$file_list{$_}=1 foreach (@ARGV);
 	}
 
-	open(CVSADM, "cvsu --ignore --types AMRO |") ||
+	# Lookup the cvsroot in CVS/Root.
+	open (ROOT, "< CVS/Root")
+		|| error ("couldn't open CVS/Root: $!");
+	<ROOT> =~ m!:([^:]+?)\n?$!; $cvs_root=$1;
+	close(ROOT);
+
+	# Lookup the path in CVS/Repository.
+	open (REPOSITORY, "< CVS/Repository")
+		|| error ("couldn't open CVS/Repository: $!");
+	<REPOSITORY> =~ m|(\S+)|; $path = $1;
+	close(REPOSITORY);
+
+	open(CVSADM, "cvsu --ignore --types AMROG |") ||
 		error ("Cannot read output of cvsu: $!");
 
 	while (<CVSADM>) {
 		chomp;
-		if ($_ !~ m{^([AMRO]) (.*)$}) {
+		if ($_ !~ m{^([AMROG]) (.*)$}) {
 			error ("Unrecognized output from cvsu");
 		}
 		my $type = $1;
 		my $file = $2;
+
+		if ($#ARGV >= 0) {
+			next unless $file_list{$file};
+			delete $file_list{$file};
+		}
+
 		if ($type eq "A") {
 			handle_added ($file);
 		}