#!/usr/bin/perl
use warnings;
use strict;

my $pattern = shift;

push @ARGV, "." unless (@ARGV);

for my $target (@ARGV) {
    open(my $svnlog_fh, '-|', 'svn', 'log', $target) or die "cannot invoke svn log $target: $!";
    my $atstart;
    while (<$svnlog_fh>) {
        if (/^------------------------------------------------------------------------$/) {
            $atstart = 1;
            next;
        }
        if ($atstart && /^r(\d+) \| /) {
            my $revline = $_;
            chomp $revline;
            my $revision = $1;
            open(my $svndiff_fh, '-|', 'svn', 'diff', "-c$revision", $target) or die "cannot invoke svn diff -c$revision $target: $!";
            local $/ = undef;
            my $diff = <$svndiff_fh>;
            if ($diff =~ m/$pattern/) {
                print "\n=== $revline ===\n$diff\n======\n\n";
            }
        }
        $atstart = 0;
    }
}

# vim: tw=0