binutils-gdb/gdb/run-on-main-thread.c
Tom Tromey 9411c49ecc Introduce run_on_main_thread
This introduces a way for a callback to be run on the main thread.

gdb/ChangeLog
2019-11-26  Tom Tromey  <tom@tromey.com>

	* run-on-main-thread.c: New file.
	* run-on-main-thread.h: New file.
	* unittests/main-thread-selftests.c: New file.
	* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
	main-thread-selftests.c.
	(HFILES_NO_SRCDIR): Add run-on-main-thread.h.
	(COMMON_SFILES): Add run-on-main-thread.c.

Change-Id: I16ef82f0564e9f8a524bdc64cb31df79a988ad9f
2019-11-26 14:02:57 -07:00

98 lines
2.4 KiB
C

/* Run a function on the main thread
Copyright (C) 2019 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "run-on-main-thread.h"
#include "ser-event.h"
#if CXX_STD_THREAD
#include <mutex>
#endif
#include "event-loop.h"
/* The serial event used when posting runnables. */
static struct serial_event *runnable_event;
/* Runnables that have been posted. */
static std::vector<std::function<void ()>> runnables;
#if CXX_STD_THREAD
/* Mutex to hold when handling RUNNABLE_EVENT or RUNNABLES. */
static std::mutex runnable_mutex;
#endif
/* Run all the queued runnables. */
static void
run_events (int error, gdb_client_data client_data)
{
std::vector<std::function<void ()>> local;
/* Hold the lock while changing the globals, but not while running
the runnables. */
{
#if CXX_STD_THREAD
std::lock_guard<std::mutex> lock (runnable_mutex);
#endif
/* Clear the event fd. Do this before flushing the events list,
so that any new event post afterwards is sure to re-awaken the
event loop. */
serial_event_clear (runnable_event);
/* Move the vector in case running a runnable pushes a new
runnable. */
local = std::move (runnables);
}
for (auto &item : local)
{
try
{
item ();
}
catch (...)
{
/* Ignore exceptions in the callback. */
}
}
}
/* See run-on-main-thread.h. */
void
run_on_main_thread (std::function<void ()> &&func)
{
#if CXX_STD_THREAD
std::lock_guard<std::mutex> lock (runnable_mutex);
#endif
runnables.emplace_back (std::move (func));
serial_event_set (runnable_event);
}
void
_initialize_run_on_main_thread ()
{
runnable_event = make_serial_event ();
add_file_handler (serial_event_fd (runnable_event), run_events, nullptr);
}