From 002401c07eec06c5cbd1a5538c44d8781954e173 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Fri, 24 Feb 2012 01:59:50 -0600
Subject: initial implementation

mostly extracted out from App::Termcast
---
 lib/Term/Filter.pm | 208 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 208 insertions(+)

diff --git a/lib/Term/Filter.pm b/lib/Term/Filter.pm
index e69de29..08e5ab1 100644
--- a/lib/Term/Filter.pm
+++ b/lib/Term/Filter.pm
@@ -0,0 +1,208 @@
+package Term::Filter;
+use Moose;
+
+use IO::Pty::Easy;
+use Scope::Guard;
+use Term::ReadKey;
+
+has callbacks => (
+    is      => 'ro',
+    isa     => 'HashRef[CodeRef]',
+    default => sub { {} },
+);
+
+sub _callback {
+    my $self = shift;
+    my ($event) = @_;
+    my $callback = $self->callbacks->{$event};
+    return unless $callback;
+    return $callback->(@_);
+}
+
+sub _has_callback {
+    my $self = shift;
+    my ($event) = @_;
+    return exists $self->callbacks->{$event};
+}
+
+has pty => (
+    is      => 'ro',
+    isa     => 'IO::Pty::Easy',
+    lazy    => 1,
+    builder => '_build_pty',
+);
+
+sub _build_pty { IO::Pty::Easy->new(raw => 0) }
+
+has input => (
+    is      => 'ro',
+    isa     => 'FileHandle',
+    lazy    => 1,
+    builder => '_build_input',
+);
+
+sub _build_input { \*STDIN }
+
+has output => (
+    is      => 'ro',
+    isa     => 'FileHandle',
+    lazy    => 1,
+    builder => '_build_output',
+);
+
+sub _build_output { \*STDOUT }
+
+has input_handles => (
+    traits   => ['Array'],
+    isa      => 'ArrayRef[FileHandle]',
+    lazy     => 1,
+    init_arg => undef,
+    builder  => '_build_input_handles',
+    handles  => {
+        input_handles => 'elements',
+    },
+);
+
+sub _build_input_handles {
+    my $self = shift;
+    [ $self->input, $self->pty ]
+}
+
+sub _build_input_select_vec {
+    my $self = shift;
+
+    my $vec = '';
+    for my $handle ($self->input_handles) {
+        vec($vec, fileno($handle), 1) = 1;
+    }
+
+    return $vec;
+}
+
+has _got_winch => (
+    is       => 'rw',
+    isa      => 'Bool',
+    default  => 0,
+    init_arg => undef,
+);
+
+has _raw_mode => (
+    is       => 'rw',
+    isa      => 'Bool',
+    default  => 0,
+    init_arg => undef,
+    trigger  => sub {
+        my $self = shift;
+        my ($val) = @_;
+        if ($val) {
+            ReadMode 5;
+        }
+        else {
+            ReadMode 0;
+        }
+    },
+);
+
+sub read_from_handle {
+    my $self = shift;
+    my ($handle, $name) = @_;
+
+    my $buf;
+    sysread $handle, $buf, 4096;
+    if (!defined $buf || length $buf == 0) {
+        Carp::croak("Error reading from $name: $!")
+            unless defined $buf;
+        return;
+    }
+
+    return $buf;
+}
+
+sub write_to_handle {
+    my $self = shift;
+    my ($handle, $buf) = @_;
+
+    # XXX should i select here? or buffer?
+    syswrite $handle, $buf;
+}
+
+sub run {
+    my $self = shift;
+    my @cmd = @_;
+
+    my $guard = $self->_setup(@cmd);
+
+    while (1) {
+        my ($rout, $eout) = $self->_retry_select;
+
+        $self->_callback('error', $eout);
+
+        if (vec($rout, fileno($self->input), 1)) {
+            my $got = $self->read_from_handle($self->input, "STDIN");
+            last unless defined $got;
+            $got = $self->_callback('munge_input', $got)
+                if $self->_has_callback('munge_input');
+            $self->write_to_handle($self->pty, $got);
+        }
+
+        if (vec($rout, fileno($self->pty), 1)) {
+            my $got = $self->read_from_handle($self->pty, "pty");
+            last unless defined $got;
+            $got = $self->_callback('munge_output', $got)
+                if $self->_has_callback('munge_output');
+            $self->write_to_handle($self->output, $got);
+        }
+
+        $self->_callback('read', $rout);
+    }
+}
+
+sub _setup {
+    my $self = shift;
+    my (@cmd) = @_;
+
+    $self->pty->spawn(@cmd) || die "Couldn't spawn @cmd: $!";
+
+    $self->_raw_mode(1);
+
+    my $prev_winch = $SIG{WINCH};
+    $SIG{WINCH} = sub {
+        $self->_got_winch(1);
+        $self->pty->slave->clone_winsize_from(\*STDIN);
+
+        $self->pty->kill('WINCH', 1);
+
+        $self->_callback('winch');
+
+        $prev_winch->();
+    };
+
+    my $undo = $self->_callback('setup', @cmd);
+
+    return Scope::Guard->new(sub {
+        $SIG{WINCH} = $prev_winch;
+        $self->_raw_mode(0);
+        $undo->() if $undo;
+    });
+}
+
+sub _retry_select {
+    my $self = shift;
+
+    my ($rout, $eout);
+    my ($rin, $ein) = ($self->_build_input_select_vec) x 2;
+    my $res = select($rout = $rin, undef, $eout = $ein, undef);
+    my $again = $!{EAGAIN} || $!{EINTR};
+
+    if (($res == -1 && $again) || $self->_got_winch) {
+        $self->_got_winch(0);
+        return $self->_retry_select;
+    }
+
+    return ($rout, $eout);
+}
+
+__PACKAGE__->meta->make_immutable;
+no Moose;
+
+1;
-- 
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