lei: run pager in client script

While most single keystrokes work fine when the pager is
launched from the background daemon, Ctrl-C and WINCH can cause
strangeness when connected to the wrong terminal.

3 files changed, 47 insertions, 12 deletions

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 1ef0cbec..d19fb311 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -26,7 +26,7 @@ use Text::Wrap qw(wrap);
 use File::Path qw(mkpath);
 use File::Spec;
 our $quit = \&CORE::exit;
-my $recv_cmd;
+my ($recv_cmd, $send_cmd);
 my $GLP = Getopt::Long::Parser->new;
 $GLP->configure(qw(gnu_getopt no_ignore_case auto_abbrev));
 my $GLP_PASS = Getopt::Long::Parser->new;
@@ -244,7 +244,8 @@ sub x_it ($$) { # pronounced "exit"
         my $sig = ($code & 127);
         $code >>= 8 unless $sig;
         if (my $sock = $self->{sock}) {
-                say $sock "exit=$code";
+                my $fds = [ map { fileno($_) } @$self{0..2} ];
+                $send_cmd->($sock, $fds, "exit=$code\n", 0);
         } else { # for oneshot
                 $quit->($code);
         }
@@ -635,15 +636,23 @@ sub start_pager {
         chomp(my $pager = <$fh> // '');
         close($fh) or warn "`git var PAGER' error: \$?=$?";
         return if $pager eq 'cat' || $pager eq '';
-        $env->{LESS} //= 'FRX';
-        $env->{LV} //= '-c';
-        $env->{COLUMNS} //= 80; # TODO TIOCGWINSZ
-        $env->{MORE} //= 'FRX' if $^O eq 'freebsd';
+        # TODO TIOCGWINSZ
+        my %new_env = (LESS => 'FRX', LV => '-c', COLUMNS => 80);
+        $new_env{MORE} = 'FRX' if $^O eq 'freebsd';
         pipe(my ($r, $wpager)) or return warn "pipe: $!";
         my $rdr = { 0 => $r, 1 => $self->{1}, 2 => $self->{2} };
+        my $pid;
+        if (my $sock = $self->{sock}) { # lei(1) process runs it
+                delete @new_env{keys %$env}; # only set iff unset
+                my $buf = "exec 1\0".$pager;
+                while (my ($k, $v) = each %new_env) { $buf .= "\0$k=$v" };
+                my $fds = [ map { fileno($_) } @$rdr{0..2} ];
+                $send_cmd->($sock, $fds, $buf .= "\n", 0);
+        } else {
+                $pid = spawn([$pager], $env, $rdr);
+        }
         $self->{1} = $wpager;
         $self->{2} = $wpager if -t $self->{2};
-        my $pid = spawn([$pager], $env, $rdr);
         $env->{GIT_PAGER_IN_USE} = 'true'; # we may spawn git
         [ $pid, @$rdr{1, 2} ];
 }
@@ -731,10 +740,13 @@ sub lazy_start {
         local $oldset = PublicInbox::DS::block_signals();
         if ($nfd == 1) {
                 require PublicInbox::CmdIPC1;
+                $send_cmd = PublicInbox::CmdIPC1->can('send_cmd1');
                 $recv_cmd = PublicInbox::CmdIPC1->can('recv_cmd1');
         } elsif ($nfd == 4) {
+                $send_cmd = PublicInbox::Spawn->can('send_cmd4');
                 $recv_cmd = PublicInbox::Spawn->can('recv_cmd4') // do {
                         require PublicInbox::CmdIPC4;
+                        $send_cmd = PublicInbox::CmdIPC4->can('send_cmd4');
                         PublicInbox::CmdIPC4->can('recv_cmd4');
                 };
         }
diff --git a/lib/PublicInbox/LeiQuery.pm b/lib/PublicInbox/LeiQuery.pm
index 9a383cef..6e778785 100644
--- a/lib/PublicInbox/LeiQuery.pm
+++ b/lib/PublicInbox/LeiQuery.pm
@@ -125,9 +125,10 @@ sub lei_q {
         # my $wcb = PublicInbox::LeiToMail->write_cb($out, $self);
         $self->{mset_opt} = \%mset_opt;
         $lxs->do_query($self, \@srcs);
-        if ($pid_old12) {
+        if ($pid_old12) { # [ pid, stdout, stderr ]
+                my $pid = $pid_old12->[0];
                 $self->{$_} = $pid_old12->[$_] for (1, 2);
-                dwaitpid($pid_old12->[0], undef, $self->{sock});
+                dwaitpid($pid, undef, $self->{sock}) if $pid;
         }
 }
 
diff --git a/script/lei b/script/lei
index bea06b2c..aac8fa94 100755
--- a/script/lei
+++ b/script/lei
@@ -6,16 +6,33 @@ use v5.10.1;
 use Socket qw(AF_UNIX SOCK_STREAM pack_sockaddr_un);
 use PublicInbox::CmdIPC4;
 my $narg = 4;
+my $recv_cmd = PublicInbox::CmdIPC4->can('recv_cmd4');
 my $send_cmd = PublicInbox::CmdIPC4->can('send_cmd4') // do {
         require PublicInbox::CmdIPC1; # 2nd choice
         $narg = 1;
+        $recv_cmd = PublicInbox::CmdIPC1->can('recv_cmd1');
         PublicInbox::CmdIPC1->can('send_cmd1');
 } // do {
         require PublicInbox::Spawn; # takes ~50ms even if built *sigh*
         $narg = 4;
+        $recv_cmd = PublicInbox::Spawn->can('recv_cmd4');
         PublicInbox::Spawn->can('send_cmd4');
 };
 
+sub exec_cmd {
+        my ($fds, $argc, @argv) = @_;
+        my %env = map { split(/=/, $_, 2) } splice(@argv, $argc);
+        my @m = (*STDIN{IO}, '<&=',  *STDOUT{IO}, '>&=',
+                *STDERR{IO}, '>&=');
+        for my $fd (@$fds) {
+                my ($old_io, $mode) = splice(@m, 0, 2);
+                open($old_io, $mode, $fd) or die "open $mode$fd: $!";
+        }
+        %ENV = (%ENV, %env);
+        exec(@argv);
+        die "exec: @argv: $!";
+}
+
 my ($sock, $pwd);
 if ($send_cmd && eval {
         my $path = do {
@@ -68,9 +85,14 @@ Falling back to (slow) one-shot mode
         select $sock;
         $| = 1; # unbuffer selected $sock
         $send_cmd->($sock, [ 0, 1, 2 ], $buf, 0);
-        while ($buf = <$sock>) {
-                $buf =~ /\Aexit=([0-9]+)\n\z/ and exit($1 + 0);
-                die $buf;
+        while (my (@fds) = $recv_cmd->($sock, $buf, 4096 * 33)) {
+                if ($buf =~ /\Aexit=([0-9]+)\n\z/) {
+                        exit($1);
+                } elsif ($buf =~ /\Aexec (.+)\n\z/) {
+                        exec_cmd(\@fds, split(/\0/, $1));
+                } else {
+                        die $buf;
+                }
         }
 } else { # for systems lacking Socket::MsgHdr, IO::FDPass or Inline::C
         warn $@ if $@;