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/*
*
* Copyright 2016 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/*
* wakeup_fd_cv uses condition variables to implement wakeup fds.
*
* It is intended for use only in cases when eventfd() and pipe() are not
* available. It can only be used with the "poll" engine.
*
* Implementation:
* A global table of cv wakeup fds is mantained. A cv wakeup fd is a negative
* file descriptor. poll() is then run in a background thread with only the
* real socket fds while we wait on a condition variable trigged by either the
* poll() completion or a wakeup_fd() call.
*
*/
#ifndef GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H
#define GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H
#include <grpc/support/sync.h>
#include "src/core/lib/iomgr/ev_posix.h"
#define FD_TO_IDX(fd) (-(fd)-1)
#define IDX_TO_FD(idx) (-(idx)-1)
typedef struct cv_node {
gpr_cv* cv;
struct cv_node* next;
struct cv_node* prev;
} cv_node;
typedef struct fd_node {
int is_set;
cv_node* cvs;
struct fd_node* next_free;
} fd_node;
typedef struct cv_fd_table {
gpr_mu mu;
gpr_refcount pollcount;
gpr_cv shutdown_cv;
fd_node* cvfds;
fd_node* free_fds;
unsigned int size;
grpc_poll_function_type poll;
} cv_fd_table;
#endif /* GRPC_CORE_LIB_IOMGR_WAKEUP_FD_CV_H */
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