lei: prefer IO::FDPass over our Inline::C recv_3fds

While our recv_3fds() implementation is more efficient
syscall-wise, loading Inline takes nearly 50ms on my machine
even after Inline::C memoizes the build.  The current ~20ms in
the fast path is barely acceptable to me, and 50ms would be
unusable.

Eventually, script/lei may invoke tcc(1) or cc(1) directly in
the fast path, but it needs @INC for the slow path, at least.

We'll encode the number of FDs into the socket name allow
parallel installations, for now.

1 files changed, 12 insertions, 6 deletions

diff --git a/script/lei b/script/lei
index 029881f8..2ea98da4 100755
--- a/script/lei
+++ b/script/lei
@@ -4,11 +4,17 @@
 use strict;
 use v5.10.1;
 use Socket qw(AF_UNIX SOCK_STREAM pack_sockaddr_un);
-my $send_3fds;
+my ($send_3fds, $nfd);
 if (my ($sock, $pwd) = eval {
-        require PublicInbox::Spawn;
-        $send_3fds = PublicInbox::Spawn->can('send_3fds') or die
-                "Inline::C not installed/configured or IO::FDPass missing\n";
+        $send_3fds = eval {
+                require IO::FDPass;
+                $nfd = 1; # 1 FD per-sendmsg
+                sub { IO::FDPass::send($_[0], $_[$_]) for (1..3) }
+        } // do {
+                require PublicInbox::Spawn; # takes ~50ms even if built *sigh*
+                $nfd = 3; # 3 FDs per-sendmsg(2)
+                PublicInbox::Spawn->can('send_3fds');
+        } // die "IO::FDPass missing or Inline::C not installed/configured\n";
         my $path = do {
                 my $runtime_dir = ($ENV{XDG_RUNTIME_DIR} // '') . '/lei';
                 if ($runtime_dir eq '/lei') {
@@ -19,7 +25,7 @@ if (my ($sock, $pwd) = eval {
                         require File::Path;
                         File::Path::mkpath($runtime_dir, 0, 0700);
                 }
-                "$runtime_dir/sock";
+                "$runtime_dir/$nfd.sock";
         };
         my $addr = pack_sockaddr_un($path);
         socket(my $sock, AF_UNIX, SOCK_STREAM, 0) or die "socket: $!";
@@ -27,7 +33,7 @@ if (my ($sock, $pwd) = eval {
                 local $ENV{PERL5LIB} = join(':', @INC);
                 open(my $daemon, '-|', $^X, qw[-MPublicInbox::LEI
                         -E PublicInbox::LEI::lazy_start(@ARGV)],
-                        $path, $! + 0) or die "popen: $!";
+                        $path, $! + 0, $nfd) or die "popen: $!";
                 while (<$daemon>) { warn $_ } # EOF when STDERR is redirected
                 close($daemon) or warn <<"";
 lei-daemon could not start, exited with \$?=$?