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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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.
*/
#ifndef _ASYNCIO_H
#define _ASYNCIO_H
#include <fcntl.h>
#include <linux/aio_abi.h>
#include <memory>
#include <signal.h>
#include <sys/cdefs.h>
#include <sys/types.h>
#include <time.h>
#include <thread>
#include <unistd.h>
/**
* Provides a subset of POSIX aio operations, as well
* as similar operations with splice and threadpools.
*/
struct aiocb {
int aio_fildes; // Assumed to be the source for splices
void *aio_buf; // Unused for splices
// Used for threadpool operations only, freed automatically
std::unique_ptr<char[]> aio_pool_buf;
off_t aio_offset;
size_t aio_nbytes;
int aio_sink; // Unused for non splice r/w
// Used internally
std::thread thread;
ssize_t ret;
int error;
~aiocb();
};
// Submit a request for IO to be completed
int aio_read(struct aiocb *);
int aio_write(struct aiocb *);
int aio_splice_read(struct aiocb *);
int aio_splice_write(struct aiocb *);
// Suspend current thread until given IO is complete, at which point
// its return value and any errors can be accessed
// All submitted requests must have a corresponding suspend.
// aiocb->aio_buf must refer to valid memory until after the suspend call
int aio_suspend(struct aiocb *[], int, const struct timespec *);
int aio_error(const struct aiocb *);
ssize_t aio_return(struct aiocb *);
// (Currently unimplemented)
int aio_cancel(int, struct aiocb *);
// Initialize a threadpool to perform IO. Only one pool can be
// running at a time.
void aio_pool_write_init();
void aio_pool_splice_init();
// Suspend current thread until all queued work is complete, then ends the threadpool
void aio_pool_end();
// Submit IO work for the threadpool to complete. Memory associated with the work is
// freed automatically when the work is complete.
int aio_pool_write(struct aiocb *);
#endif // ASYNCIO_H
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