X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FProcessPipe.pm;h=1bc792c4bada77676916b10f330e87d1c0d9b98f;hb=refs%2Fheads%2Fmaster;hp=eade524caada14ae99d4815822ec9738bef1f7ce;hpb=617f35dacbd4e5972bf2d82411b45009bbc79a42;p=public-inbox.git

diff --git a/lib/PublicInbox/ProcessPipe.pm b/lib/PublicInbox/ProcessPipe.pm
index eade524c..1bc792c4 100644
--- a/lib/PublicInbox/ProcessPipe.pm
+++ b/lib/PublicInbox/ProcessPipe.pm
@@ -1,30 +1,72 @@
-# Copyright (C) 2016 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
-# a tied handle for auto reaping of children tied to a pipe, see perltie(1)
+# a tied handle for auto reaping of children tied to a read-only pipe, see perltie(1)
+# DO NOT use this as-is for bidirectional pipes/sockets (e.g. in PublicInbox::Git),
+# both ends of the pipe must be at the same level of the Perl object hierarchy
+# to ensure orderly destruction.
 package PublicInbox::ProcessPipe;
-use strict;
-use warnings;
+use v5.12;
+use PublicInbox::DS qw(awaitpid);
+
+sub waitcb { # awaitpid callback
+	my ($pid, $err_ref, $cb, @args) = @_;
+	$$err_ref = $?; # sets >{pp_chld_err} for _close
+	$cb->($pid, @args) if $cb;
+}
 
 sub TIEHANDLE {
-	my ($class, $pid, $fh) = @_;
-	bless { pid => $pid, fh => $fh }, $class;
+	my ($cls, $pid, $fh, @cb_arg) = @_;
+	my $self = bless { pid => $pid, fh => $fh, ppid => $$ }, $cls;
+	# we share $err (and not $self) with awaitpid to avoid a ref cycle
+	$self->{pp_chld_err} = \(my $err);
+	awaitpid($pid, \&waitcb, \$err, @cb_arg);
+	$self;
 }
 
-sub READ { sysread($_[0]->{fh}, $_[1], $_[2], $_[3] || 0) }
+sub BINMODE { binmode(shift->{fh}) } # for IO::Uncompress::Gunzip
+
+sub READ { read($_[0]->{fh}, $_[1], $_[2], $_[3] || 0) }
 
 sub READLINE { readline($_[0]->{fh}) }
 
-sub CLOSE { close($_[0]->{fh}) }
+sub WRITE {
+	use bytes qw(length);
+	syswrite($_[0]->{fh}, $_[1], $_[2] // length($_[1]), $_[3] // 0);
+}
+
+sub PRINT {
+	my $self = shift;
+	print { $self->{fh} } @_;
+}
 
 sub FILENO { fileno($_[0]->{fh}) }
 
-sub DESTROY {
-	my $fh = delete($_[0]->{fh});
-	close $fh if $fh;
-	waitpid($_[0]->{pid}, 0);
+sub _close ($;$) {
+	my ($self, $wait) = @_;
+	my ($fh, $pid) = delete(@$self{qw(fh pid)});
+	my $ret = defined($fh) ? close($fh) : '';
+	return $ret unless defined($pid) && $self->{ppid} == $$;
+	if ($wait) { # caller cares about the exit status:
+		# synchronous wait via defined(wantarray) on awaitpid:
+		defined(${$self->{pp_chld_err}}) or $wait = awaitpid($pid);
+		($? = ${$self->{pp_chld_err}}) and $ret = '';
+	} else {
+		awaitpid($pid); # depends on $in_loop or not
+	}
+	$ret;
 }
 
-sub pid { $_[0]->{pid} }
+# if caller uses close(), assume they want to check $? immediately so
+# we'll waitpid() synchronously.  n.b. wantarray doesn't seem to
+# propagate `undef' down to tied methods, otherwise I'd rely on that.
+sub CLOSE { _close($_[0], 1) }
+
+# if relying on DESTROY, assume the caller doesn't care about $? and
+# we can let the event loop call waitpid() whenever it gets SIGCHLD
+sub DESTROY {
+	_close($_[0]);
+	undef;
+}
 
 1;