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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H
#define GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H
#include "src/core/iomgr/wakeup_fd_posix.h"
#include <grpc/support/sync.h>
/* pollset kicking allows breaking a thread out of polling work for
a given pollset.
writing a byte to a pipe is used as a posix-ly portable base
mechanism, and eventfds are utilized on Linux for better performance. */
typedef struct grpc_kick_fd_info {
grpc_wakeup_fd_info wakeup_fd;
/* used for polling list and free list */
struct grpc_kick_fd_info *next;
/* only used when polling */
struct grpc_kick_fd_info *prev;
} grpc_kick_fd_info;
typedef struct grpc_pollset_kick_state {
gpr_mu mu;
int kicked;
struct grpc_kick_fd_info fd_list;
} grpc_pollset_kick_state;
#define GRPC_POLLSET_KICK_GET_FD(kick_fd_info) \
GRPC_WAKEUP_FD_GET_READ_FD(&(kick_fd_info)->wakeup_fd)
/* This is an abstraction around the typical pipe mechanism for waking up a
thread sitting in a poll() style call. */
void grpc_pollset_kick_global_init(void);
void grpc_pollset_kick_global_destroy(void);
void grpc_pollset_kick_init(grpc_pollset_kick_state *kick_state);
void grpc_pollset_kick_destroy(grpc_pollset_kick_state *kick_state);
/* Guarantees a pure posix implementation rather than a specialized one, if
* applicable. Intended for testing. */
void grpc_pollset_kick_global_init_fallback_fd(void);
/* Must be called before entering poll(). If return value is NULL, this consumed
an existing kick. Otherwise the return value is an FD to add to the poll set.
*/
grpc_kick_fd_info *grpc_pollset_kick_pre_poll(
grpc_pollset_kick_state *kick_state);
/* Consume an existing kick. Must be called after poll returns that the fd was
readable, and before calling kick_post_poll. */
void grpc_pollset_kick_consume(grpc_pollset_kick_state *kick_state,
grpc_kick_fd_info *fd_info);
/* Must be called after pre_poll, and after consume if applicable */
void grpc_pollset_kick_post_poll(grpc_pollset_kick_state *kick_state,
grpc_kick_fd_info *fd_info);
/* Actually kick */
void grpc_pollset_kick_kick(grpc_pollset_kick_state *kick_state);
#endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_KICK_POSIX_H */
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