129 lines
2.8 KiB
C++
129 lines
2.8 KiB
C++
/*
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* Copyright (C) 2014-2016 Paul Davis <paul@linuxaudiosystems.com>
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* Copyright (C) 2015-2016 Robin Gareus <robin@gareus.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <poll.h>
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CrossThreadChannel::CrossThreadChannel (bool non_blocking)
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: receive_channel (0)
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, receive_source (0)
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{
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fds[0] = -1;
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fds[1] = -1;
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if (pipe (fds)) {
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error << "cannot create x-thread pipe for read (%2)" << ::strerror (errno) << endmsg;
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return;
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}
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if (non_blocking) {
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if (fcntl (fds[0], F_SETFL, O_NONBLOCK)) {
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error << "cannot set non-blocking mode for x-thread pipe (read) (" << ::strerror (errno) << ')' << endmsg;
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return;
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}
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if (fcntl (fds[1], F_SETFL, O_NONBLOCK)) {
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error << "cannot set non-blocking mode for x-thread pipe (write) (%2)" << ::strerror (errno) << ')' << endmsg;
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return;
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}
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}
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receive_channel = g_io_channel_unix_new (fds[0]);
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}
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CrossThreadChannel::~CrossThreadChannel ()
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{
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if (receive_source) {
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/* this disconnects it from any main context it was attached in
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in ::attach(), this prevent its callback from being invoked
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after the destructor has finished.
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*/
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g_source_destroy (receive_source);
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}
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if (receive_channel) {
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g_io_channel_unref (receive_channel);
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receive_channel = 0;
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}
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if (fds[0] >= 0) {
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close (fds[0]);
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fds[0] = -1;
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}
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if (fds[1] >= 0) {
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close (fds[1]);
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fds[1] = -1;
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}
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}
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void
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CrossThreadChannel::wakeup ()
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{
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char c = 0;
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(void) ::write (fds[1], &c, 1);
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}
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void
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CrossThreadChannel::drain ()
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{
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char buf[64];
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while (::read (fds[0], buf, sizeof (buf)) > 0) {};
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}
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int
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CrossThreadChannel::deliver (char msg)
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{
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return ::write (fds[1], &msg, 1);
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}
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bool
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CrossThreadChannel::poll_for_request()
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{
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struct pollfd pfd[1];
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pfd[0].fd = fds[0];
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pfd[0].events = POLLIN|POLLERR|POLLHUP;
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while(true) {
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if (poll (pfd, 1, -1) < 0) {
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if (errno == EINTR) {
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continue;
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}
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break;
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}
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if (pfd[0].revents & ~POLLIN) {
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break;
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}
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if (pfd[0].revents & POLLIN) {
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return true;
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}
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}
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return false;
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}
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int
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CrossThreadChannel::receive (char& msg, bool wait)
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{
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if (wait) {
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if (!poll_for_request ()) {
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return -1;
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}
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}
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return ::read (fds[0], &msg, 1);
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}
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