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.

1 files changed, 25 insertions, 3 deletions

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 $@;