#!/usr/bin/env perl

use warnings;
use strict;

our $VERSION   = '1.58';
our $COPYRIGHT = 'Copyright 2005-2007 Andy Lester, all rights reserved.';
# Check http://petdance.com/ack/ for updates

# These are all our globals.
my $is_windows;
my %opt;
my %type_wanted;
my $is_tty =  -t STDOUT;

BEGIN {
    $is_windows = ($^O =~ /MSWin32/);
    eval 'use Term::ANSIColor ();' unless $is_windows;

    $ENV{ACK_COLOR_MATCH}    ||= 'black on_yellow';
    $ENV{ACK_COLOR_FILENAME} ||= 'bold green';
}

use Getopt::Long;

MAIN: {
    if ( $App::Ack::VERSION ne $main::VERSION ) {
        App::Ack::die( "Program/library version mismatch\n\t$0 is $main::VERSION\n\t$INC{'App/Ack.pm'} is $App::Ack::VERSION" );
    }
    if ( exists $ENV{ACK_SWITCHES} ) {
        App::Ack::warn( 'ACK_SWITCHES is no longer supported.  Use ACK_OPTIONS.' );
    }

    # Priorities! Get the --thpppt checking out of the way.
    /^--th[bp]+t$/ && App::Ack::_thpppt($_) for @ARGV;

    my %defaults = (
        all     => 0,
        color   => $is_tty && !$is_windows,
        follow  => 0,
        group   => $is_tty,
        m       => 0,
    );

    my %options = (
        'A|after-context=i'     => \$opt{A},
        'B|before-context=i'    => \$opt{B},
        'C|context=i'           => sub { shift; $opt{A} = $opt{B} = shift; },
        a           => \$opt{all},
        'all!'      => \$opt{all},
        c           => \$opt{count},
        'color!'    => \$opt{color},
        count       => \$opt{count},
        f           => \$opt{f},
        'follow!'   => \$opt{follow},
        'group!'    => \$opt{group},
        h           => \$opt{h},
        H           => \$opt{H},
        'i|ignore-case'         => \$opt{i},
        'l|files-with-match'    => \$opt{l},
        'm|max-count=i'         => \$opt{m},
        n                       => \$opt{n},
        'o|output:s'            => \$opt{o},
        'Q|literal'             => \$opt{Q},
        'sort-files'            => \$opt{sort_files},
        'v|invert-match'        => \$opt{v},
        'w|word-regexp'         => \$opt{w},


        'version'   => sub { App::Ack::version_statement( $COPYRIGHT ); exit 1; },
        'help|?:s'  => sub { shift; App::Ack::show_help(@_); exit; },
        'help-types'=> sub { App::Ack::show_help_types(); exit; },
        'man'       => sub {require Pod::Usage; Pod::Usage::pod2usage({-verbose => 2}); exit},

        'type=s'    => sub {
            # Whatever --type=xxx they specify, set it manually in the hash
            my $dummy = shift;
            my $type = shift;
            my $wanted = ($type =~ s/^no//) ? 0 : 1; # must not be undef later

            if ( exists $type_wanted{ $type } ) {
                $type_wanted{ $type } = $wanted;
            }
            else {
                App::Ack::die( qq{Unknown --type "$type"} );
            }
        }, # type sub
    );

    my @filetypes_supported = App::Ack::filetypes_supported();
    for my $i ( @filetypes_supported ) {
        $options{ "$i!" } = \$type_wanted{ $i };
    }

    # Stick any default switches at the beginning, so they can be overridden
    # by the command line switches.
    unshift @ARGV, split( ' ', $ENV{ACK_OPTIONS} ) if defined $ENV{ACK_OPTIONS};

    Getopt::Long::Configure( 'bundling', 'no_ignore_case' );
    GetOptions( %options ) && App::Ack::options_sanity_check( %opt ) or
        App::Ack::die( 'See ack --help or ack --man for options.' );

    if ( $opt{A} || $opt{B} ) {
        App::Ack::die( q{Sorry, but the -A, -B and -C options haven't actually been implemented yet.} );
    }

    # Apply defaults
    while ( my ($key,$value) = each %defaults ) {
        if ( not defined $opt{$key} ) {
            $opt{$key} = $value;
        }
    }

    if ( defined( my $val = $opt{o} ) ) {
        if ( $val eq '' ) {
            $val = q{$&};
        }
        else {
            $val = qq{"$val"};
        }
        $opt{o} = eval qq[ sub { $val } ];
    }

    my $filetypes_supported_set =   grep { defined $type_wanted{$_} && ($type_wanted{$_} == 1) } @filetypes_supported;
    my $filetypes_supported_unset = grep { defined $type_wanted{$_} && ($type_wanted{$_} == 0) } @filetypes_supported;

    # If anyone says --no-whatever, we assume all other types must be on.
    if ( !$filetypes_supported_set ) {
        for my $i ( keys %type_wanted ) {
            $type_wanted{$i} = 1 unless ( defined( $type_wanted{$i} ) || $i eq 'binary' );
        }
    }

    if ( !@ARGV && !$opt{f} ) {
        App::Ack::show_help();
        exit 1;
    }

    my $regex;

    if ( !$opt{f} ) {
        # REVIEW: This shouldn't be able to happen because of the help
        # check above.
        $regex = shift @ARGV or App::Ack::die( 'No regex specified' );

        $regex = quotemeta( $regex ) if $opt{Q};
        $regex = "\\b$regex\\b"      if $opt{w};

        $regex = $opt{i} ? qr/$regex/i : qr/$regex/;
    }

    my @what;
    if ( @ARGV ) {
        @what = $is_windows ? glob( @ARGV ) : @ARGV;

        # Show filenames unless we've specified one single file
        $opt{show_filename} = (@what > 1) || (!-f $what[0]);
    }
    else {
        my $is_filter = !-t STDIN;
        if ( $is_filter ) {
            # We're going into filter mode
            for ( qw( f l ) ) {
                $opt{$_} and App::Ack::die( "Can't use -$_ when acting as a filter." );
            }
            $opt{show_filename} = 0;
            search( '-', $regex, %opt );
            exit 0;
        }
        else {
            @what = '.'; # Assume current directory
            $opt{show_filename} = 1;
        }
    }
    $opt{show_filename} = 0 if $opt{h};
    $opt{show_filename} = 1 if $opt{H};
    $opt{show_filename} = 0 if $opt{o};

    my $file_filter = $opt{all} ? \&dash_a : \&is_interesting;
    my $descend_filter = $opt{n} ? sub {0} : \&App::Ack::skipdir_filter;

    my $iter =
        File::Next::files( {
            file_filter     => $file_filter,
            descend_filter  => $descend_filter,
            error_handler   => sub { my $msg = shift; App::Ack::warn( $msg ) },
            sort_files      => $opt{sort_files},
            follow_symlinks => $opt{follow},
        }, @what );


    while ( defined ( my $file = $iter->() ) ) {
        if ( $opt{f} ) {
            print "$file\n";
        }
        else {
            search( $file, $regex, %opt );
        }
    }
    exit 0;
}

sub is_interesting {
    return if /^\./;

    for my $type ( App::Ack::filetypes( $File::Next::name ) ) {
        return 1 if $type_wanted{$type};
    }
    return;
}

sub dash_a {
    return !App::Ack::should_ignore( $File::Next::name );
}

sub search {
    my $filename = shift;
    my $regex = shift;
    my %opt = @_;

    my $is_binary;

    my $fh;
    if ( $filename eq '-' ) {
        $fh = *STDIN;
        $is_binary = 0;
    }
    else {
        if ( !open( $fh, '<', $filename ) ) {
            App::Ack::warn( "$filename: $!" );
            return;
        }
        $is_binary = -B $filename;
    }

    # Negated counting is a pain, so I'm putting it in its own
    # optimizable subroutine.
    if ( $opt{v} ) {
        return _search_v( $fh, $is_binary, $filename, $regex, %opt );
    }

    my $nmatches = 0;
    local $_ = undef;
    while (<$fh>) {
        next unless /$regex/;
        ++$nmatches;
        next if $opt{count}; # Counting means no lines

        # No point in searching more if we only want a list,
        # and don't want a count.
        last if $opt{l};

        if ( $is_binary ) {
            print "Binary file $filename matches\n";
            last;
        }

        my $out;
        if ( $opt{o} ) {
            $out = $opt{o}->() . "\n";
        }
        else {
            $out = $_;
            $out =~ s/($regex)/Term::ANSIColor::colored($1,$ENV{ACK_COLOR_MATCH})/eg if $opt{color};
        }

        if ( $opt{show_filename} ) {
            my $display_filename =
                $opt{color}
                    ? Term::ANSIColor::colored( $filename, $ENV{ACK_COLOR_FILENAME} )
                    : $filename;
            if ( $opt{group} ) {
                print "$display_filename\n" if $nmatches == 1;
                print "$.:";
            }
            else {
                print "${display_filename}:$.:";
            }
        }
        print $out;

        last if $opt{m} && ( $nmatches >= $opt{m} );
    } # while
    close $fh;

    if ( $opt{count} ) {
        if ( $nmatches || !$opt{l} ) {
            print "${filename}:" if $opt{show_filename};
            print "${nmatches}\n";
        }
    }
    elsif ( $opt{l} ) {
        print "$filename\n" if $nmatches;
    }
    else {
        print "\n" if $nmatches && $opt{show_filename} && $opt{group};
    }

    return;
}   # search()


sub _search_v {
    my $fh = shift;
    my $is_binary = shift;
    my $filename = shift;
    my $regex = shift;
    my %opt = @_;

    my $nmatches = 0; # Although in here, it's really $n_non_matches. :-)

    my $show_lines = !($opt{l} || $opt{count});
    local $_ = undef;
    while (<$fh>) {
        if ( /$regex/ ) {
            return if $opt{l}; # For list mode, any match means we can bail
            next;
        }
        else {
            ++$nmatches;
            if ( $show_lines ) {
                if ( $is_binary ) {
                    print "Binary file $filename matches\n";
                    last;
                }
                print "${filename}:" if $opt{show_filename};
                print $_;
                last if $opt{m} && ( $nmatches >= $opt{m} );
            }
        }
    } # while
    close $fh;

    if ( $opt{count} ) {
        print "${filename}:" if $opt{show_filename};
        print "${nmatches}\n";
    }
    else {
        print "$filename\n" if $opt{l};
    }

    return;
} # _search_v()


=head1 NAME

ack - grep-like text finder

=head1 SYNOPSIS

    ack [options] PATTERN [FILE...]
    ack -f [options] [DIRECTORY...]

=head1 DESCRIPTION

Ack is designed as a replacement for F<grep>.

Ack searches the named input FILEs (or standard input if no files are
named, or the file name - is given) for lines containing a match to the
given PATTERN.  By default, ack prints the matching lines.

Ack can also list files that would be searched, without actually searching
them, to let you take advantage of ack's file-type filtering capabilities.

=head1 FILE SELECTION

I<ack> is intelligent about the files it searches.  It knows about
certain file types, based on both the extension on the file and,
in some cases, the contents of the file.  These selections can be
made with the B<--type> option.

With no file selections, I<ack> only searches files of types that
it recognizes.  If you have a file called F<foo.wango>, and I<ack>
doesn't know what a .wango file is, I<ack> won't search it.

The B<-a> option tells I<ack> to select all files, regardless of
type.

Some files will never be selected by I<ack>, even with B<-a>,
including:

=over 4

=item * Backup files: Files ending with F<~>, or F<#*#>

=item * Coredumps: Files matching F<core.\d+>

=back

=head1 DIRECTORY SELECTION

I<ack> descends through the directory tree of the starting directories
specified.  However, it will ignore the shadow directories used by
many version control systems, and the build directories used by the
Perl MakeMaker system.

The following directories will never be descended into: F<_darcs>,
F<CVS>, F<RCS>, F<SCCS>, F<.svn>, F<blib>, F<.git>

=head1 WHEN TO USE GREP

I<ack> trumps I<grep> as an everyday tool 99% of the time, but don't
throw I<grep> away, because there are times you'll still need it.

I<ack> only searches through files of types that it recognizes.  If
it can't tell what type a file is, then it won't look.  If that's
annoying to you, use I<grep>.

If you truly want to search every file and every directory, I<ack>
won't do it.  You'll need to rely on I<grep>.

If you need context around your matches, use I<grep>, but check
back in on I<ack> in the near future, because I'm adding it.

=head1 OPTIONS

=over 4

=item B<-a>, B<--all>

Operate on all files, regardless of type (but still skip directories
like F<blib>, F<CVS>, etc.

=item B<-A I<NUM>>, B<--after-context=I<NUM>>

Print I<NUM> lines of trailing context after matching lines.  Places
a line containing -- between contiguous groups of matches.

=item B<-B I<NUM>>, B<--before-context=I<NUM>>

Print I<NUM> lines of leading context before matching lines.  Places
a line containing -- between contiguous groups of matches.

=item B<-C I<NUM>>, B<--context=I<NUM>>

Print I<NUM> lines of context before and after matching lines.
Places a line containing -- between contiguous groups of matches.

=item B<-c>, B<--count>

Suppress normal output; instead print a count of matching lines for
each input file.  If B<-l> is in effect, it will only show the
number of lines for each file that has lines matching.  Without
B<-l>, some line counts may be zeroes.

=item B<--color>, B<--nocolor>

B<--color> highlights the matching text.  B<--nocolor> supresses
the color.  This is on by default unless the output is redirected,
or running under Windows.

=item B<-f>

Only print the files that would be searched, without actually doing
any searching.  PATTERN must not be specified, or it will be taken as
a path to search.

=item B<--follow>, B<--nofollow>

Follow or don't follow symlinks, other than whatever starting files
or directories were specified on the command line.

This is off by default.

=item B<--group>, B<--nogroup>

B<--group> groups matches by file name with.  This is the default when
used interactively.

B<--nogroup> prints one result per line, like grep.  This is the default
when output is redirected.

=item B<-H>, B<--with-filename>

Print the filename for each match.

=item B<-h>, B<--no-filename>

Suppress the prefixing of filenames on output when multiple files are
searched.

=item B<--help>

Print a short help statement.

=item B<-i>, B<--ignore-case>

Ignore case in the search strings.

=item B<-l>, B<--files-with-matches>

Only print the filenames of matching files, instead of the matching text.

=item B<-m=I<NUM>>, B<--max-count=I<NUM>>

Stop reading a file after I<NUM> matches.

=item B<--man>

Print this manual page.

=item B<-n>

No descending into subdirectories.

=item B<-o>

Show only the part of each line matching PATTERN (turns off text
highlighting)

=item B<--output=I<expr>>

Output the evaluation of I<expr> for each line (turns off text
highlighting)

=item B<-Q>

Quote all metacharacters.  PATTERN is treated as a literal.

=item B<--sort-files>

Sorts the found files lexically.  Use this if you want your file
listings to be deterministic between runs of I<ack>.

=item B<--thpppt>

Display the crucial Bill The Cat logo.  Note that the exact spelling
of B<--thpppppt> is not important.  It's checked against a regular
expression.

=item B<--type=TYPE>, B<--type=noTYPE>

Specify the types of files to include or exclude from a search.
TYPE is a filetype, like I<perl> or I<xml>.  B<--type=perl> can
also be specified as B<--perl>, and B<--type=noperl> can be done
as B<--noperl>.

Type specifications can be repeated and are ORed together.

See I<ack --help=types> for a list of valid types.

=item B<-v>, B<--invert-match>

Invert match: select non-matching lines

=item B<--version>

Display version and copyright information.

=item B<-w>, B<--word-regexp>

Force PATTERN to match only whole words.  The PATTERN is wrapped with
C<\b> metacharacters.

=back

=head1 ENVIRONMENT VARIABLES

=over 4

=item ACK_OPTIONS

This variable specifies default options to be placed in front of
any explicit options on the command line.

=item ACK_COLOR_FILENAME

Specifies the color of the filename when it's printed in B<--group>
mode.  By default, it's "bold green".

The recognized attributes are clear, reset, dark, bold, underline,
underscore, blink, reverse, concealed black, red, green, yellow,
blue, magenta, on_black, on_red, on_green, on_yellow, on_blue,
on_magenta, on_cyan, and on_white.  Case is not significant.
Underline and underscore are equivalent, as are clear and reset.
The color alone sets the foreground color, and on_color sets the
background color.

=item ACK_COLOR_MATCH

Specifies the color of the matching text when printed in B<--color>
mode.  By default, it's "black on_yellow".

See B<ACK_COLOR_FILENAME> for the color specifications.

=back

=head1 GOTCHAS

Note that FILES must still match valid selection rules.  For example,

    ack something --perl foo.rb

will search nothing, because I<foo.rb> is a Ruby file.

=head1 AUTHOR

Andy Lester, C<< <andy at petdance.com> >>

=head1 BUGS

Please report any bugs or feature requests to
C<bug-ack at rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ack>.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.

=head1 SUPPORT

Support for and information about F<ack> can be found at:

=over 4

=item * The ack homepage

L<http://petdance.com/ack/>

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/ack>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/ack>

=item * RT: CPAN's request tracker

L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=ack>

=item * Search CPAN

L<http://search.cpan.org/dist/ack>

=item * Subversion repository

L<http://ack.googlecode.com/svn/>

=back

=head1 ACKNOWLEDGEMENTS

How appropriate to have I<ack>nowledgements!

Thanks to everyone who has contributed to ack in any way, including
Matt Diephouse,
Christian Jaeger,
Bill Sully,
Bill Ricker,
David Golden,
Nilson Santos F. Jr,
Elliot Shank,
Merijn Broeren,
Uwe Voelker,
Rick Scott,
Ask Bjørn Hansen,
Jerry Gay,
Will Coleda,
Mike O'Regan,
Slaven Rezic,
Mark Stosberg,
David Alan Pisoni,
Adriano Ferreira,
James Keenan,
Leland Johnson,
Ricardo Signes
and Pete Krawczyk.

=head1 COPYRIGHT & LICENSE

Copyright 2005-2007 Andy Lester, all rights reserved.

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=cut
package File::Next;

use strict;
use warnings;


our $VERSION = '0.38';



use File::Spec ();


our $name; # name of the current file
our $dir;  # dir of the current file

our %files_defaults;
our %skip_dirs;

BEGIN {
    %files_defaults = (
        file_filter     => undef,
        descend_filter  => undef,
        error_handler   => sub { CORE::die @_ },
        sort_files      => undef,
        follow_symlinks => 1,
    );
    %skip_dirs = map {($_,1)} (File::Spec->curdir, File::Spec->updir);
}

sub files {
    my ($parms,@queue) = _setup( \%files_defaults, @_ );

    return sub {
        while (@queue) {
            my ($dir,$file,$fullpath) = splice( @queue, 0, 3 );
            if (-f $fullpath) {
                if ( $parms->{file_filter} ) {
                    local $_ = $file;
                    local $File::Next::dir = $dir;
                    local $File::Next::name = $fullpath;
                    next if not $parms->{file_filter}->();
                }
                return wantarray ? ($dir,$file,$fullpath) : $fullpath;
            }
            elsif (-d $fullpath) {
                unshift( @queue, _candidate_files( $parms, $fullpath ) );
            }
        } # while

        return;
    }; # iterator
}

sub dirs {
    my ($parms,@queue) = _setup( \%files_defaults, @_ );

    return sub {
        while (@queue) {
            my ($dir,$file,$fullpath) = splice( @queue, 0, 3 );
            if (-d $fullpath) {
                unshift( @queue, _candidate_files( $parms, $fullpath ) );
                return $fullpath;
            }
        } # while

        return;
    }; # iterator
}

sub sort_standard($$)   { return $_[0]->[1] cmp $_[1]->[1] };
sub sort_reverse($$)    { return $_[1]->[1] cmp $_[0]->[1] };

sub reslash {
    my $path = shift;

    my @parts = split( /\//, $path );

    return $path if @parts < 2;

    return File::Spec->catfile( @parts );
}



sub _setup {
    my $defaults = shift;
    my $passed_parms = ref $_[0] eq 'HASH' ? {%{+shift}} : {}; # copy parm hash

    my %passed_parms = %{$passed_parms};

    my $parms = {};
    for my $key ( keys %$defaults ) {
        $parms->{$key} =
            exists $passed_parms{$key}
                ? delete $passed_parms{$key}
                : $defaults->{$key};
    }

    # Any leftover keys are bogus
    for my $badkey ( keys %passed_parms ) {
        my $sub = (caller(1))[3];
        $parms->{error_handler}->( "Invalid parameter passed to $sub(): $badkey" );
    }

    # If it's not a code ref, assume standard sort
    if ( $parms->{sort_files} && ( ref($parms->{sort_files}) ne 'CODE' ) ) {
        $parms->{sort_files} = \&sort_standard;
    }
    my @queue;

    for ( @_ ) {
        my $start = reslash( $_ );
        if (-d $start) {
            push @queue, ($start,undef,$start);
        }
        else {
            push @queue, (undef,$start,$start);
        }
    }

    return ($parms,@queue);
}


sub _candidate_files {
    my $parms = shift;
    my $dir = shift;

    my $dh;
    if ( !opendir $dh, $dir ) {
        $parms->{error_handler}->( "$dir: $!" );
        return;
    }

    my @newfiles;
    while ( my $file = readdir $dh ) {
        next if $skip_dirs{$file};

        # Only do directory checking if we have a descend_filter
        my $fullpath = File::Spec->catdir( $dir, $file );
        if ( !$parms->{follow_symlinks} ) {
            next if -l $fullpath;
        }

        if ( $parms->{descend_filter} && -d $fullpath ) {
            local $File::Next::dir = $fullpath;
            local $_ = $file;
            next if not $parms->{descend_filter}->();
        }
        push( @newfiles, $dir, $file, $fullpath );
    }
    if ( my $sub = $parms->{sort_files} ) {
        my @triplets;
        while ( @newfiles ) {
            push @triplets, [splice( @newfiles, 0, 3 )];
        }
        @newfiles = map { @{$_} } sort $sub @triplets;
    }

    return @newfiles;
}


1; # End of File::Next
package App::Ack;

use warnings;
use strict;


our $VERSION;
BEGIN {
    $VERSION = '1.58';
}

our %types;
our %mappings;
our @ignore_dirs;
our %ignore_dirs;
our $path_sep;
our $is_cygwin;

BEGIN {
    @ignore_dirs = qw( blib CVS RCS SCCS .svn _darcs .git );
    %ignore_dirs = map { ($_,1) } @ignore_dirs;
    %mappings = (
        asm         => [qw( s S )],
        binary      => q{Binary files, as defined by Perl's -B op (default: off)},
        cc          => [qw( c h xs )],
        cpp         => [qw( cpp m h C H )],
        csharp      => [qw( cs )],
        css         => [qw( css )],
        elisp       => [qw( el )],
        haskell     => [qw( hs lhs )],
        html        => [qw( htm html shtml )],
        lisp        => [qw( lisp )],
        java        => [qw( java )],
        js          => [qw( js )],
        mason       => [qw( mas )],
        ocaml       => [qw( ml mli )],
        parrot      => [qw( pir pasm pmc ops pod pg tg )],
        perl        => [qw( pl pm pod tt ttml t )],
        php         => [qw( php phpt )],
        python      => [qw( py )],
        ruby        => [qw( rb rhtml rjs )],
        scheme      => [qw( scm )],
        shell       => [qw( sh bash csh ksh zsh )],
        sql         => [qw( sql ctl )],
        tcl         => [qw( tcl )],
        tex         => [qw( tex cls sty )],
        tt          => [qw( tt tt2 )],
        vim         => [qw( vim )],
        yaml        => [qw( yaml yml )],
        xml         => [qw( xml dtd xslt )],
    );

    use File::Spec ();
    $path_sep = File::Spec->catfile( '', '' );
    $path_sep = quotemeta( $path_sep );

    while ( my ($type,$exts) = each %mappings ) {
        if ( ref $exts ) {
            for my $ext ( @{$exts} ) {
                push( @{$types{$ext}}, $type );
            }
        }
    }

    $is_cygwin = ($^O eq 'cygwin');
}


sub skipdir_filter {
    return !exists $ignore_dirs{$_};
}


sub filetypes {
    my $filename = shift;

    return '-ignore' if should_ignore( $filename );

    # If there's an extension, look it up
    if ( $filename =~ m{\.([^\.$path_sep]+)$} ) {
        my $ref = $types{lc $1};
        return @{$ref} if $ref;
    }

    return unless -e $filename;

    # From Elliot Shank:
    #     I can't see any reason that -r would fail on these-- the ACLs look
    #     fine, and no program has any of them open, so the busted Windows
    #     file locking model isn't getting in there.  If I comment the if
    #     statement out, everything works fine
    # So, for cygwin, don't bother trying to check for readability.
    if ( !$is_cygwin ) {
        if ( !-r $filename ) {
            App::Ack::warn( "$filename: Permission denied" );
            return;
        }
    }

    return 'binary' if -B $filename;

    # If there's no extension, or we don't recognize it, check the shebang line
    my $fh;
    if ( !open( $fh, '<', $filename ) ) {
        App::Ack::warn( "$filename: $!" );
        return;
    }
    my $header = <$fh>;
    close $fh;
    return unless defined $header;
    if ( $header =~ /^#!/ ) {
        return 'perl'   if $header =~ /\bperl/;
        return 'php'    if $header =~ /\bphp\b/;
        return 'python' if $header =~ /\bpython\b/;
        return 'ruby'   if $header =~ /\bruby\b/;
        return 'shell'  if $header =~ /\b(ba|c|k|z)?sh\b/;
    }
    return 'xml' if $header =~ /<\?xml /;

    return;
}


sub should_ignore {
    my $filename = shift;

    return 1 if $filename =~ /~$/;
    return 1 if $filename =~ m{$path_sep?#.+#$};
    return 1 if $filename =~ m{$path_sep?core\.\d+$};

    return;
}


sub options_sanity_check {
    my %opts = @_;
    my $ok = 1;

    $ok = 0 if _option_conflict( \%opts, 'l', [qw( A B C o group )] );
    $ok = 0 if _option_conflict( \%opts, 'l', [qw( m )] );
    $ok = 0 if _option_conflict( \%opts, 'f', [qw( A B C o m group )] );

    return $ok;
}

sub _option_conflict {
    my $opts = shift;
    my $used = shift;
    my $exclusives = shift;

    return if not defined $opts->{$used};

    my $bad = 0;
    for ( @$exclusives ) {
        if ( defined $opts->{$_} ) {
            print "The ", _opty($_), " option cannot be used with the ", _opty($used), " option.\n";
            $bad = 1;
        }
    }

    return $bad;
}

sub _opty {
    my $opt = shift;
    return length($opt)>1 ? "--$opt" : "-$opt";
}


sub warn {
    CORE::warn( _my_program(), ": ", @_, "\n" );
}


sub die {
    CORE::die( _my_program(), ": ", @_, "\n" );
}

sub _my_program {
    require File::Basename;
    return File::Basename::basename( $0 );
}



sub filetypes_supported {
    return keys %mappings;
}

sub _thpppt {
    my $y = q{_   /|,\\'!.x',=(www)=,   U   };
    $y =~ tr/,x!w/\nOo_/;
    print "$y ack $_[0]!\n";
    exit 0;
}


sub show_help {
    my $help_arg = shift || 0;

    return show_help_types() if $help_arg =~ /^types?/;

    my $ignore_dirs = _listify( @ignore_dirs );

    print <<"END_OF_HELP";
Usage: ack [OPTION]... PATTERN [FILES]
Search for PATTERN in each source file in the tree from cwd on down.
If [FILES] is specified, then only those files/directories are checked.
ack may also search STDIN, but only if no FILES are specified, or if
one of FILES is "-".

Default switches may be specified in ACK_OPTIONS environment variable.

Example: ack -i select

Searching:
    -i              Ignore case distinctions
    -v              Invert match: select non-matching lines
    -w              Force PATTERN to match only whole words
    -Q              Quote all metacharacters; expr is literal

Search output:
    -l              Only print filenames containing matches
    -o              Show only the part of a line matching PATTERN
                    (turns off text highlighting)
    --output=expr   Output the evaluation of expr for each line
                    (turns off text highlighting)
    -m=NUM          Stop after NUM matches
    -H              Print the filename for each match
    -h              Suppress the prefixing filename on output
    -c, --count     Show number of lines matching per file

    --group         Group matches by file name.
                    (default: on when used interactively)
    --nogroup       One result per line, including filename, like grep
                    (default: on when the output is redirected)

    --[no]color     Highlight the matching text (default: on unless
                    output is redirected, or on Windows)

Context control:
    -B, --before-context=NUM
    -A, --after-context=NUM
    -C, --context=NUM
                    print NUM lines of context before and/or after
                    matching lines

File finding:
    -f              Only print the files found, without searching.
                    The PATTERN must not be specified.
    --sort-files    Sort the found files lexically.

File inclusion/exclusion:
    -n              No descending into subdirectories
    -a, --all       All files, regardless of extension (but still skips
                    $ignore_dirs dirs)
    --perl          Include only Perl files.
    --type=perl     Include only Perl files.
    --noperl        Exclude Perl files.
    --type=noperl   Exclude Perl files.
                    See "ack --help type" for supported filetypes.
    --[no]follow    Follow symlinks.  Default is off.

Miscellaneous:
    --help          This help
    --man           Man page
    --version       Display version & copyright
    --thpppt        Bill the Cat
END_OF_HELP

    return;
}



sub show_help_types {
    print <<'END_OF_HELP';
Usage: ack [OPTION]... PATTERN [FILES]

The following is the list of filetypes supported by ack.  You can
specify a file type with the --type=TYPE format, or the --TYPE
format.  For example, both --type=perl and --perl work.

Note that some extensions may appear in multiple types.  For example,
.pod files are both Perl and Parrot.

END_OF_HELP

    my @types = filetypes_supported();
    for my $type ( sort @types ) {
        next if $type =~ /^-/; # Stuff to not show
        my $ext_list = $mappings{$type};

        if ( ref $ext_list ) {
            $ext_list = join( ' ', map { ".$_" } @{$ext_list} );
        }
        printf( "    --[no]%-9.9s %s\n", $type, $ext_list );
    }

    return;
}

sub _listify {
    my @whats = @_;

    return '' if !@whats;

    my $end = pop @whats;
    return @whats ? join( ', ', @whats ) . " and $end" : $end;
}


sub version_statement {
    my $copyright = shift;
    print <<"END_OF_VERSION";
ack $App::Ack::VERSION

$copyright

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
END_OF_VERSION

    return;
}

1; # End of App::Ack