#!/usr/bin/env perl

# A hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message
# if it wants to stop the commit.

use strict;
use File::Temp qw/ :mktemp  /;
use File::Copy;
use Cwd;

$ENV{LC_ALL} = "C";

sub check_whitespaces($)
{
    my ($h) = @_;

    my $found_bad = 0;
    my $filename;
    my $reported_filename = "";
    my $lineno;
    sub bad_line {
	my ($why, $line) = @_;
	if (!$found_bad) {
	    print STDERR "*\n";
	    print STDERR "* You have some suspicious patch lines:\n";
	    print STDERR "*\n";
	    $found_bad = 1;
	}
	if ($reported_filename ne $filename) {
	    print STDERR "* In $filename\n";
	    $reported_filename = $filename;
	}
	print STDERR "* $why (line $lineno)\n";
	print STDERR "$filename:$lineno:$line\n";
    }
    open( FILES, "git-diff-index -p -M --cached $h |" ) ||  die "Cannot run git diff-index.";
    while (<FILES>) {
	if (m|^diff --git a/(.*) b/\1$|) {
	    $filename = $1;
	    next;
	}
	if (/^@@ -\S+ \+(\d+)/) {
	    $lineno = $1 - 1;
	    next;
	}
	if (/^ /) {
	    $lineno++;
	    next;
	}
	if (s/^\+//) {
	    $lineno++;
	    chomp;
	    if (/^(?:[<>=]){7}/) {
		bad_line("unresolved merge conflict", $_);
	    }
	}
    }
    if ( $found_bad)
    {
	exit($found_bad);
    }
}

# Do the work :-)

# Initial commit: diff against an empty tree object
my $against="4b825dc642cb6eb9a060e54bf8d69288fbee4904";
if ( system( "git rev-parse --verify HEAD >/dev/null 2>&1" ) == 0 ) {
    $against="HEAD"
}

# fix whitespace in code
check_whitespaces( $against );

# all OK
exit( 0 );
# vi:set shiftwidth=4 expandtab: