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emacsclient: avoid background chatter

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* lib-src/emacsclient.c (process_grouping): New function.
(act_on_signals, main): Use it.
(main): Omit "Waiting for Emacs..." and later "\n" messages
if in background, since that messes up the screen.
This commit is contained in:
Paul Eggert 2018-12-06 10:46:06 -08:00
parent 2f985977f6
commit 46b8100811
1 changed files with 33 additions and 18 deletions
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51
lib-src/emacsclient.c
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@ -1095,6 +1095,26 @@ find_tty (const char **tty_type, const char **tty_name, bool noabort)
return true;
}
/* Return the process group if in the foreground, the negative of the
process group if in the background, and zero if there is no
foreground process group for the controlling terminal.
Unfortunately, use of this function introduces an unavoidable race,
since whether the process is in the foreground or background can
change at any time. */
static pid_t
process_grouping (void)
{
#ifdef SOCKETS_IN_FILE_SYSTEM
pid_t tcpgrp = tcgetpgrp (STDOUT_FILENO);
if (0 <= tcpgrp)
{
pid_t pgrp = getpgrp ();
return tcpgrp == pgrp ? pgrp : -pgrp;
}
#endif
return 0;
}
#ifdef SOCKETS_IN_FILE_SYSTEM
@ -1253,21 +1273,17 @@ act_on_signals (HSOCKET emacs_socket)
{
got_sigcont = 0;
took_action = true;
pid_t tcpgrp = tcgetpgrp (STDOUT_FILENO);
if (0 <= tcpgrp)
pid_t grouping = process_grouping ();
if (grouping < 0)
{
pid_t pgrp = getpgrp ();
if (tcpgrp == pgrp)
if (tty)
{
/* We are in the foreground. */
send_to_emacs (emacs_socket, "-resume \n");
}
else if (tty)
{
/* We are in the background; cancel the continue. */
kill (-pgrp, SIGTTIN);
/* Cancel the continue. */
kill (grouping, SIGTTIN);
}
}
else
send_to_emacs (emacs_socket, "-resume \n");
}
if (got_sigtstp)
@ -1767,13 +1783,12 @@ main (int argc, char **argv)
exit (EXIT_FAILURE);
}
#ifndef WINDOWSNT
#ifdef SOCKETS_IN_FILE_SYSTEM
if (tty)
{
pid_t pgrp = getpgrp ();
pid_t tcpgrp = tcgetpgrp (STDOUT_FILENO);
if (0 <= tcpgrp && tcpgrp != pgrp)
kill (-pgrp, SIGTTIN);
pid_t grouping = process_grouping ();
if (grouping < 0)
kill (grouping, SIGTTIN);
}
#endif
@ -1946,7 +1961,7 @@ main (int argc, char **argv)
send_to_emacs (emacs_socket, "\n");
/* Wait for an answer. */
if (!eval && !tty && !nowait && !quiet)
if (!eval && !tty && !nowait && !quiet && 0 <= process_grouping ())
{
printf ("Waiting for Emacs...");
skiplf = false;
@ -2052,7 +2067,7 @@ main (int argc, char **argv)
}
}
if (!skiplf)
if (!skiplf && 0 <= process_grouping ())
printf ("\n");
if (rl < 0)