124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
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*
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* Copyright (C) 2012 Colin Walters <walters@verbum.org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Author: Colin Walters <walters@verbum.org>
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*/
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#include "config.h"
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#include "otutil.h"
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#include <glib-unix.h>
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#include <string.h>
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#include <sys/eventfd.h>
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#include <errno.h>
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#include <unistd.h>
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struct OtWaitableQueue {
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volatile gint refcount;
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GMutex mutex;
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int fd;
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gboolean read_empty;
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GQueue queue;
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};
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OtWaitableQueue *
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ot_waitable_queue_new (void)
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{
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OtWaitableQueue *queue = g_new0 (OtWaitableQueue, 1);
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queue->refcount = 1;
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g_mutex_init (&queue->mutex);
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g_queue_init (&queue->queue);
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queue->fd = eventfd (0, EFD_CLOEXEC | EFD_NONBLOCK);
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g_assert (queue->fd >= 0);
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return queue;
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}
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void
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ot_waitable_queue_push (OtWaitableQueue *queue,
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gpointer data)
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{
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const guint64 val = 1;
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int rval;
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g_mutex_lock (&queue->mutex);
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g_queue_push_head (&queue->queue, data);
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do
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rval = write (queue->fd, &val, sizeof (val));
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while (G_UNLIKELY (rval == -1 && errno == EINTR));
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queue->read_empty = FALSE;
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g_mutex_unlock (&queue->mutex);
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}
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gboolean
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ot_waitable_queue_pop (OtWaitableQueue *queue,
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gpointer *out_data)
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{
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gpointer ret = NULL;
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gboolean empty = TRUE;
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int rval;
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guint64 val;
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g_mutex_lock (&queue->mutex);
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if (g_queue_peek_tail_link (&queue->queue) != NULL)
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{
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ret = g_queue_pop_tail (&queue->queue);
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empty = FALSE;
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}
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else if (!queue->read_empty)
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{
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do
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rval = read (queue->fd, &val, sizeof (val));
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while (G_UNLIKELY (rval == -1 && errno == EINTR));
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queue->read_empty = TRUE;
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}
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g_mutex_unlock (&queue->mutex);
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*out_data = ret;
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return !empty;
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}
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void
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ot_waitable_queue_ref (OtWaitableQueue *queue)
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{
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g_atomic_int_inc (&queue->refcount);
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}
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void
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ot_waitable_queue_unref (OtWaitableQueue *queue)
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{
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if (!g_atomic_int_dec_and_test (&queue->refcount))
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return;
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g_mutex_clear (&queue->mutex);
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g_queue_clear (&queue->queue);
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(void) close (queue->fd);
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g_free (queue);
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}
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GSource *
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ot_waitable_queue_create_source (OtWaitableQueue *queue)
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{
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GIOChannel *iochan = g_io_channel_unix_new (queue->fd);
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GSource *source = g_io_create_watch (iochan, G_IO_IN);
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g_io_channel_unref (iochan);
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return source;
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}
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