Send errors from child process to parent and print to Irssi

We previously `die`d in the child process when we encountered an error,
but this didn't kill the child process. Instead, we needed to
`POSIX::_exit(1);` in order to really exit. When `die`ing, the `print`
messages in the child would actally get up to the parent, but now that
we exit correctly they no longer do.

In order to get the messages to the parent so the parent can print them
to Irssi, I tried a couple things. First I tried creating a new pipe
between the parent and child, but this didn't get me the messages
printing.

Asked on Freenode#irssi, and Nei suggested using the same pipe I'm
already using but with a distinguishing prefix for 'ok' and 'error'.
Gave it a try and this time it worked! Yay!

1 files changed, 85 insertions, 16 deletions

diff --git a/vimput.pl b/vimput.pl
index c325a71..01a90bf 100644
--- a/vimput.pl
+++ b/vimput.pl
@@ -17,7 +17,10 @@ our %IRSSI = {
 
 
 use constant CTRL_X => 24;
+use constant ERROR_PREFIX => 'ERROR: ';
+use constant OK_PREFIX => 'OK: ';
 
+my $child;
 my $forked = 0;
 
 
@@ -39,34 +42,48 @@ sub write_input {
 
 # Open a Tmux split containing a Vim instance editing the vimput_file.
 sub open_tmux_split {
-	my ($fifo) = @_;
+	my ($fifo, $error_handle) = @_;
+	# my ($fifo) = @_;
 
 	if (!$ENV{TMUX}) {
-		print 'no tmux'; # TODO: Replace with Irssi print
-						 # MSGLEVEL_CLIENTERROR
-		return;
+		# Irssi::print('Not running in tmux.', MSGLEVEL_CLIENTERROR);
+		print $error_handle ERROR_PREFIX . 'Not running in tmux.';
+
+		return 0;
 	}
 
 	my $random_unused_filename = tmpnam();
 
 	my $command = "vim -c 'set buftype=acwrite' -c 'read ${\vimput_file}' -c '1 delete _' -c 'autocmd BufWriteCmd <buffer> :write $fifo | set nomodified' $random_unused_filename";
 	system('tmux', 'split-window', $command);
+
+	return 1;
 }
 
 
 sub update_input_line_when_finished {
 	return if $forked;
 
-	my ($read_handle, $write_handle);
+	my ($read_handle, $write_handle, $err_read_handle, $err_write_handle);
 
 	pipe($read_handle, $write_handle);
+	# pipe($err_read_handle, $err_write_handle);
+
+	sub cleanup {
+		close $read_handle;
+		close $write_handle;
+		# close $err_read_handle;
+		# close $err_write_handle;
+	}
 
 	my $pid = fork();
+	$child = $pid;
 
 	if (!defined $pid) {
-		print "Failed to fork: $!";  # TODO: Irssi print
-		close $read_handle;
-		close $write_handle;
+		Irssi::print("Failed to fork: $!", MSGLEVEL_CLIENTERROR);
+
+		cleanup();
+
 		return;
 	}
 
@@ -75,15 +92,31 @@ sub update_input_line_when_finished {
 	if (is_child_fork($pid)) {
 		my $fifo_path = tmpnam();
 
-		open_tmux_split($fifo_path);
-
-		mkfifo($fifo_path, 0600) or die $!;
-
-		open my $fifo, '<', $fifo_path or die $!;
+		open_tmux_split($fifo_path, $write_handle) or do {
+		# print $err_write_handle 'Not running in tmux.';
+			# print 'fuck';
+			# Irssi::print('fuck');
+			# print $write_handle 'ERROR: Not running in tmux.';
+			cleanup();
+			# die;
+			POSIX::_exit(1);
+		};
+
+		mkfifo($fifo_path, 0600) or do {
+			cleanup();
+			# die $!;
+			POSIX::_exit(1);
+		};
+
+		open my $fifo, '<', $fifo_path or do {
+			cleanup();
+			# die $!;
+			POSIX::_exit(1);
+		};
 		$fifo->autoflush(1);
 
 		while (<$fifo>) {
-			print $write_handle $_;
+			print $write_handle OK_PREFIX . $_;
 		}
 
 		close $fifo;
@@ -105,6 +138,15 @@ sub update_input_line_when_finished {
 			\&pipe_input,
 			\@args,
 		);
+
+		# my $err_pipe_tag;
+		# my @err_args = ($err_read_handle, \$err_pipe_tag);
+		# $err_pipe_tag = Irssi::input_add(
+		# 	fileno $err_read_handle,
+		# 	Irssi::INPUT_READ,
+		# 	\&pipe_error,
+		# 	\@err_args,
+		# );
 	}
 }
 
@@ -114,9 +156,18 @@ sub pipe_input {
 	my ($read_handle, $pipe_tag) = @$args;
 
 	my $input = <$read_handle>;
-	chomp $input;
 
-	Irssi::gui_input_set($input);
+	if (index($input, ERROR_PREFIX) == 0) {
+		$input = substr($input, length(ERROR_PREFIX));
+
+		Irssi::print($input, MSGLEVEL_CLIENTERROR);
+	}
+	elsif (index($input, OK_PREFIX) == 0) {
+		$input = substr($input, length(OK_PREFIX));
+		chomp $input;
+
+		Irssi::gui_input_set($input);
+	}
 
 	$forked = 0;
 
@@ -125,6 +176,24 @@ sub pipe_input {
 }
 
 
+sub pipe_error {
+	my ($args) = @_;
+	my ($err_read_handle, $err_pipe_tag) = @$args;
+
+	my $input = <$err_read_handle>;
+
+	Irssi::print($input, MSGLEVEL_CLIENTERROR);
+
+	$forked = 0;
+
+	close $err_read_handle;
+	Irssi::input_remove($$err_pipe_tag);
+
+	kill 'TERM', $child;
+	undef $child;
+}
+
+
 sub is_child_fork {
 	my ($pid) = @_;