io: add helper module for creating watches on FDs
A number of the channel implementations will require the ability to create watches on file descriptors / sockets. To avoid duplicating this code in each channel, provide a helper API for dealing with file descriptor watches. There are two watch implementations provided. The first is useful for bi-directional file descriptors such as sockets, regular files, character devices, etc. The second works with a pair of unidirectional file descriptors such as pipes. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
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Daniel P. Berrange
parent
666a3af9c8
commit
1c809fa01d
72
include/io/channel-watch.h
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72
include/io/channel-watch.h
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/*
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* QEMU I/O channels watch helper APIs
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*
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* Copyright (c) 2015 Red Hat, Inc.
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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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef QIO_CHANNEL_WATCH_H__
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#define QIO_CHANNEL_WATCH_H__
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#include "io/channel.h"
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/*
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* This module provides helper functions that will be needed by
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* the various QIOChannel implementations, for creating watches
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* on file descriptors / sockets
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*/
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/**
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* qio_channel_create_fd_watch:
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* @ioc: the channel object
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* @fd: the file descriptor
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* @condition: the I/O condition
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*
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* Create a new main loop source that is able to
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* monitor the file descriptor @fd for the
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* I/O conditions in @condition. This is able
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* monitor block devices, character devices,
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* sockets, pipes but not plain files.
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*
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* Returns: the new main loop source
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*/
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GSource *qio_channel_create_fd_watch(QIOChannel *ioc,
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int fd,
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GIOCondition condition);
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/**
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* qio_channel_create_fd_pair_watch:
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* @ioc: the channel object
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* @fdread: the file descriptor for reading
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* @fdwrite: the file descriptor for writing
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* @condition: the I/O condition
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*
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* Create a new main loop source that is able to
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* monitor the pair of file descriptors @fdread
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* and @fdwrite for the I/O conditions in @condition.
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* This is intended for monitoring unidirectional
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* file descriptors such as pipes, where a pair
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* of descriptors is required for bidirectional
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* I/O
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*
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* Returns: the new main loop source
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*/
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GSource *qio_channel_create_fd_pair_watch(QIOChannel *ioc,
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int fdread,
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int fdwrite,
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GIOCondition condition);
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#endif /* QIO_CHANNEL_WATCH_H__ */
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@ -1 +1,2 @@
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io-obj-y = channel.o
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io-obj-y += channel-watch.o
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198
io/channel-watch.c
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198
io/channel-watch.c
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@ -0,0 +1,198 @@
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/*
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* QEMU I/O channels watch helper APIs
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*
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* Copyright (c) 2015 Red Hat, Inc.
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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, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "io/channel-watch.h"
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typedef struct QIOChannelFDSource QIOChannelFDSource;
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struct QIOChannelFDSource {
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GSource parent;
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GPollFD fd;
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QIOChannel *ioc;
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GIOCondition condition;
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};
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typedef struct QIOChannelFDPairSource QIOChannelFDPairSource;
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struct QIOChannelFDPairSource {
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GSource parent;
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GPollFD fdread;
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GPollFD fdwrite;
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QIOChannel *ioc;
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GIOCondition condition;
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};
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static gboolean
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qio_channel_fd_source_prepare(GSource *source G_GNUC_UNUSED,
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gint *timeout)
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{
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*timeout = -1;
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return FALSE;
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}
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static gboolean
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qio_channel_fd_source_check(GSource *source)
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{
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QIOChannelFDSource *ssource = (QIOChannelFDSource *)source;
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return ssource->fd.revents & ssource->condition;
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}
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static gboolean
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qio_channel_fd_source_dispatch(GSource *source,
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GSourceFunc callback,
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gpointer user_data)
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{
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QIOChannelFunc func = (QIOChannelFunc)callback;
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QIOChannelFDSource *ssource = (QIOChannelFDSource *)source;
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return (*func)(ssource->ioc,
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ssource->fd.revents & ssource->condition,
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user_data);
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}
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static void
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qio_channel_fd_source_finalize(GSource *source)
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{
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QIOChannelFDSource *ssource = (QIOChannelFDSource *)source;
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object_unref(OBJECT(ssource->ioc));
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}
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static gboolean
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qio_channel_fd_pair_source_prepare(GSource *source G_GNUC_UNUSED,
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gint *timeout)
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{
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*timeout = -1;
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return FALSE;
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}
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static gboolean
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qio_channel_fd_pair_source_check(GSource *source)
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{
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QIOChannelFDPairSource *ssource = (QIOChannelFDPairSource *)source;
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GIOCondition poll_condition = ssource->fdread.revents |
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ssource->fdwrite.revents;
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return poll_condition & ssource->condition;
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}
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static gboolean
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qio_channel_fd_pair_source_dispatch(GSource *source,
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GSourceFunc callback,
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gpointer user_data)
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{
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QIOChannelFunc func = (QIOChannelFunc)callback;
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QIOChannelFDPairSource *ssource = (QIOChannelFDPairSource *)source;
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GIOCondition poll_condition = ssource->fdread.revents |
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ssource->fdwrite.revents;
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return (*func)(ssource->ioc,
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poll_condition & ssource->condition,
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user_data);
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}
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static void
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qio_channel_fd_pair_source_finalize(GSource *source)
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{
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QIOChannelFDPairSource *ssource = (QIOChannelFDPairSource *)source;
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object_unref(OBJECT(ssource->ioc));
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}
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GSourceFuncs qio_channel_fd_source_funcs = {
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qio_channel_fd_source_prepare,
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qio_channel_fd_source_check,
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qio_channel_fd_source_dispatch,
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qio_channel_fd_source_finalize
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};
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GSourceFuncs qio_channel_fd_pair_source_funcs = {
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qio_channel_fd_pair_source_prepare,
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qio_channel_fd_pair_source_check,
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qio_channel_fd_pair_source_dispatch,
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qio_channel_fd_pair_source_finalize
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};
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GSource *qio_channel_create_fd_watch(QIOChannel *ioc,
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int fd,
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GIOCondition condition)
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{
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GSource *source;
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QIOChannelFDSource *ssource;
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source = g_source_new(&qio_channel_fd_source_funcs,
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sizeof(QIOChannelFDSource));
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ssource = (QIOChannelFDSource *)source;
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ssource->ioc = ioc;
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object_ref(OBJECT(ioc));
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ssource->condition = condition;
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ssource->fd.fd = fd;
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ssource->fd.events = condition;
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g_source_add_poll(source, &ssource->fd);
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return source;
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}
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GSource *qio_channel_create_fd_pair_watch(QIOChannel *ioc,
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int fdread,
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int fdwrite,
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GIOCondition condition)
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{
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GSource *source;
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QIOChannelFDPairSource *ssource;
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source = g_source_new(&qio_channel_fd_pair_source_funcs,
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sizeof(QIOChannelFDPairSource));
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ssource = (QIOChannelFDPairSource *)source;
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ssource->ioc = ioc;
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object_ref(OBJECT(ioc));
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ssource->condition = condition;
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ssource->fdread.fd = fdread;
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ssource->fdread.events = condition & G_IO_IN;
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ssource->fdwrite.fd = fdwrite;
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ssource->fdwrite.events = condition & G_IO_OUT;
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g_source_add_poll(source, &ssource->fdread);
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g_source_add_poll(source, &ssource->fdwrite);
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return source;
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}
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