pipe.h

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// MIT License
//
// Copyright (c) 2026 Christian Spoo
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
 
#ifndef _MINIOS_FS_PIPE_H_
#define _MINIOS_FS_PIPE_H_
 
#include <miniOS/types.h>
 
/* Forward-declare the ops struct to break the circular include with vfs.h.
 * vfs.h includes pipe.h (pipe_t in vfs_file_t); pipe.h uses struct vfs_ops *
 * to avoid needing the full vfs_ops_t typedef. The typedef and full definition
 * live in vfs.h which callers should include directly. */
struct vfs_ops;

#define PIPE_SIZE 4096

typedef struct {
    uint8_t  buf[PIPE_SIZE];
    uint32_t write_pos;    /* monotonically increasing; use % PIPE_SIZE to index */
    uint32_t read_pos;     /* monotonically increasing; use % PIPE_SIZE to index */
    uint32_t ref_count;    /* total number of fds (read + write ends) alive */
    uint8_t  write_closed; /* non-zero when all write-end fds have been closed */
} pipe_t;

pipe_t *pipe_create(void);

int pipe_read(uint32_t ino, uint64_t off, void *buf, uint32_t len);

int pipe_write(uint32_t ino, uint64_t off, const void *buf, uint32_t len);

void pipe_free(pipe_t *p);

extern struct vfs_ops pipe_ops;

int pipe_write_buf(pipe_t *p, const void *buf, uint32_t len);
int pipe_read_buf(pipe_t *p, void *buf, uint32_t len);
 
#endif /* _MINIOS_FS_PIPE_H_ */