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// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
/**
* Asynchronous I/O queues.
*/
#ifndef BFS_IOQ_H
#define BFS_IOQ_H
#include <stddef.h>
/**
* An queue of asynchronous I/O operations.
*/
struct ioq;
/**
* I/O queue operations.
*/
enum ioq_op {
/** ioq_close(). */
IOQ_CLOSE,
/** ioq_opendir(). */
IOQ_OPENDIR,
/** ioq_closedir(). */
IOQ_CLOSEDIR,
};
/**
* An I/O queue entry.
*/
struct ioq_ent {
/** The I/O operation. */
enum ioq_op op;
/** The return value of the operation. */
int ret;
/** The error code, if the operation failed. */
int error;
/** Arbitrary user data. */
void *ptr;
/** Operation-specific arguments. */
union {
/** ioq_close() args. */
struct ioq_close {
int fd;
} close;
/** ioq_opendir() args. */
struct ioq_opendir {
struct bfs_dir *dir;
int dfd;
const char *path;
} opendir;
/** ioq_closedir() args. */
struct ioq_closedir {
struct bfs_dir *dir;
} closedir;
};
};
/**
* Create an I/O queue.
*
* @param depth
* The maximum depth of the queue.
* @param nthreads
* The maximum number of background threads.
* @return
* The new I/O queue, or NULL on failure.
*/
struct ioq *ioq_create(size_t depth, size_t nthreads);
/**
* Check the remaining capacity of a queue.
*/
size_t ioq_capacity(const struct ioq *ioq);
/**
* Asynchronous close().
*
* @param ioq
* The I/O queue.
* @param fd
* The fd to close.
* @param ptr
* An arbitrary pointer to associate with the request.
* @return
* 0 on success, or -1 on failure.
*/
int ioq_close(struct ioq *ioq, int fd, void *ptr);
/**
* Asynchronous bfs_opendir().
*
* @param ioq
* The I/O queue.
* @param dir
* The allocated directory.
* @param dfd
* The base file descriptor.
* @param path
* The path to open, relative to dfd.
* @param ptr
* An arbitrary pointer to associate with the request.
* @return
* 0 on success, or -1 on failure.
*/
int ioq_opendir(struct ioq *ioq, struct bfs_dir *dir, int dfd, const char *path, void *ptr);
/**
* Asynchronous bfs_closedir().
*
* @param ioq
* The I/O queue.
* @param dir
* The directory to close.
* @param ptr
* An arbitrary pointer to associate with the request.
* @return
* 0 on success, or -1 on failure.
*/
int ioq_closedir(struct ioq *ioq, struct bfs_dir *dir, void *ptr);
/**
* Pop a response from the queue.
*
* @param ioq
* The I/O queue.
* @return
* The next response, or NULL.
*/
struct ioq_ent *ioq_pop(struct ioq *ioq);
/**
* Pop a response from the queue, without blocking.
*
* @param ioq
* The I/O queue.
* @return
* The next response, or NULL.
*/
struct ioq_ent *ioq_trypop(struct ioq *ioq);
/**
* Free a queue entry.
*
* @param ioq
* The I/O queue.
* @param ent
* The entry to free.
*/
void ioq_free(struct ioq *ioq, struct ioq_ent *ent);
/**
* Cancel any pending I/O operations.
*/
void ioq_cancel(struct ioq *ioq);
/**
* Stop and destroy an I/O queue.
*/
void ioq_destroy(struct ioq *ioq);
#endif // BFS_IOQ_H
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