qspawn: introduce new psgi_yield API

This is intended to replace psgi_return and HTTPD/Async
entirely, hopefully making our code less convoluted while
maintaining the ability to handle slow clients on
memory-constrained systems

This was made possible by the philosophy shift in commit 21a539a2df0c
(httpd/async: switch to buffering-as-fast-as-possible, 2019-06-28).

We'll still support generic PSGI via the `pull' model with a
GetlineResponse class which is similar to the old GetlineBody.

1 files changed, 7 insertions, 5 deletions

diff --git a/lib/PublicInbox/InputPipe.pm b/lib/PublicInbox/InputPipe.pm
index b38d8270..f4d57e7d 100644
--- a/lib/PublicInbox/InputPipe.pm
+++ b/lib/PublicInbox/InputPipe.pm
@@ -39,14 +39,16 @@ sub consume {
         if ($@) { # regular file (but not w/ select|IO::Poll backends)
                 $self->{-need_rq} = 1;
                 $self->requeue;
-        } elsif (-p $in || -S _) { # O_NONBLOCK for sockets and pipes
+        } elsif (do { no warnings 'unopened'; !stat($in) }) { # ProcessIONBF
+        } elsif (-p _ || -S _) { # O_NONBLOCK for sockets and pipes
                 $in->blocking(0);
         } elsif (-t $in) { # isatty(3) can't use `_' stat cache
                 unblock_tty($self);
         }
+        $self;
 }
 
-sub close {
+sub close { # idempotent
         my ($self) = @_;
         if (my $t = delete($self->{restore_termios})) {
                 my $fd = fileno($self->{sock} // return);
@@ -60,16 +62,16 @@ sub event_step {
         my $r = sysread($self->{sock} // return, my $rbuf, 65536);
         eval {
                 if ($r) {
-                        $self->{cb}->(@{$self->{args}}, $rbuf);
+                        $self->{cb}->($self, @{$self->{args}}, $rbuf);
                         $self->requeue if $self->{-need_rq};
                 } elsif (defined($r)) { # EOF
-                        $self->{cb}->(@{$self->{args}}, '');
+                        $self->{cb}->($self, @{$self->{args}}, '');
                         $self->close
                 } elsif ($!{EAGAIN}) { # rely on EPOLLIN
                 } elsif ($!{EINTR}) { # rely on EPOLLIN for sockets/pipes/tty
                         $self->requeue if $self->{-need_rq};
                 } else { # another error
-                        $self->{cb}->(@{$self->{args}}, undef);
+                        $self->{cb}->($self, @{$self->{args}}, undef);
                         $self->close;
                 }
         };