ds: add a note about planned future changes

[public-inbox.git] / lib / PublicInbox / DS.pm

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 751ae410a5f0649a38fe371febe7c96916e31fe0..3b0cbe67ede9a146531a43f0d967d5a654cb0184 100644 (file)
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -5,19 +5,23 @@
 #
 # This is a fork of the (for now) unmaintained Danga::Socket 1.61.
 # Unused features will be removed, and updates will be made to take
-# advantage of newer kernels
-
+# advantage of newer kernels.
+#
+# API changes to diverge from Danga::Socket will happen to better
+# accomodate new features and improve scalability.  Do not expect
+# this to be a stable API like Danga::Socket.
+# Bugs encountered (and likely fixed) are reported to
+# bug-Danga-Socket@rt.cpan.org and visible at:
+# https://rt.cpan.org/Public/Dist/Display.html?Name=Danga-Socket
 package PublicInbox::DS;
 use strict;
 use bytes;
 use POSIX ();
 use Time::HiRes ();
-
-use vars qw{$VERSION};
-$VERSION = "1.61";
+use IO::Handle qw();
+use Fcntl qw(FD_CLOEXEC F_SETFD F_GETFD);
 
 use warnings;
-no  warnings qw(deprecated);
 
 use PublicInbox::Syscall qw(:epoll);
 
@@ -34,7 +38,6 @@ use fields ('sock',              # underlying socket
 
 use Errno  qw(EINPROGRESS EWOULDBLOCK EISCONN ENOTSOCK
               EPIPE EAGAIN EBADF ECONNRESET ENOPROTOOPT);
-use Socket qw(IPPROTO_TCP);
 use Carp   qw(croak confess);
 
 use constant DebugLevel => 0;
@@ -52,7 +55,8 @@ our (
      $HaveKQueue,
      %DescriptorMap,             # fd (num) -> PublicInbox::DS object
      $Epoll,                     # Global epoll fd (for epoll mode only)
-     $KQueue,                    # Global kqueue fd (for kqueue mode only)
+     $KQueue,                    # Global kqueue fd ref (for kqueue mode only)
+     $_io,                       # IO::Handle for Epoll
      @ToClose,                   # sockets to close when event loop is done
 
      $PostLoopCallback,          # subref to call at the end of each loop, if defined (global)
@@ -86,30 +90,17 @@ sub Reset {
     %PLCMap = ();
     $DoneInit = 0;
 
-    POSIX::close($Epoll)  if defined $Epoll  && $Epoll  >= 0;
-    POSIX::close($KQueue) if defined $KQueue && $KQueue >= 0;
+    # NOTE kqueue is close-on-fork, and we don't account for it, yet
+    # OTOH, we (public-inbox) don't need this sub outside of tests...
+    POSIX::close($$KQueue) if !$_io && $KQueue && $$KQueue >= 0;
+    $KQueue = undef;
 
-    *EventLoop = *FirstTimeEventLoop;
-}
+    $_io = undef; # close $Epoll
+    $Epoll = undef;
 
-=head2 C<< CLASS->HaveEpoll() >>
-
-Returns a true value if this class will use IO::Epoll for async IO.
-
-=cut
-sub HaveEpoll {
-    _InitPoller();
-    return $HaveEpoll;
+    *EventLoop = *FirstTimeEventLoop;
 }
 
-=head2 C<< CLASS->ToClose() >>
-
-Return the list of sockets that are awaiting close() at the end of the
-current event loop.
-
-=cut
-sub ToClose { return @ToClose; }
-
 =head2 C<< CLASS->SetLoopTimeout( $timeout ) >>
 
 Set the loop timeout for the event loop to some value in milliseconds.
@@ -169,6 +160,16 @@ sub AddTimer {
     die "Shouldn't get here.";
 }
 
+# keeping this around in case we support other FD types for now,
+# epoll_create1(EPOLL_CLOEXEC) requires Linux 2.6.27+...
+sub set_cloexec ($) {
+    my ($fd) = @_;
+
+    $_io = IO::Handle->new_from_fd($fd, 'r+') or return;
+    defined(my $fl = fcntl($_io, F_GETFD, 0)) or return;
+    fcntl($_io, F_SETFD, $fl | FD_CLOEXEC);
+}
+
 sub _InitPoller
 {
     return if $DoneInit;
@@ -176,7 +177,7 @@ sub _InitPoller
 
     if ($HAVE_KQUEUE) {
         $KQueue = IO::KQueue->new();
-        $HaveKQueue = $KQueue >= 0;
+        $HaveKQueue = defined $KQueue;
         if ($HaveKQueue) {
             *EventLoop = *KQueueEventLoop;
         }
@@ -185,6 +186,7 @@ sub _InitPoller
         $Epoll = eval { epoll_create(1024); };
         $HaveEpoll = defined $Epoll && $Epoll >= 0;
         if ($HaveEpoll) {
+            set_cloexec($Epoll);
             *EventLoop = *EpollEventLoop;
         }
     }