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/****************************************************************************
* bfs *
* Copyright (C) 2015-2019 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
/**
* A file-walking API based on nftw().
*/
#ifndef BFS_BFTW_H
#define BFS_BFTW_H
#include "mtab.h"
#include "stat.h"
#include <stddef.h>
/**
* Possible file types.
*/
enum bftw_typeflag {
/** Unknown type. */
BFTW_UNKNOWN = 0,
/** Block device. */
BFTW_BLK = 1 << 0,
/** Character device. */
BFTW_CHR = 1 << 1,
/** Directory. */
BFTW_DIR = 1 << 2,
/** Solaris door. */
BFTW_DOOR = 1 << 3,
/** Pipe. */
BFTW_FIFO = 1 << 4,
/** Symbolic link. */
BFTW_LNK = 1 << 5,
/** Solaris event port. */
BFTW_PORT = 1 << 6,
/** Regular file. */
BFTW_REG = 1 << 7,
/** Socket. */
BFTW_SOCK = 1 << 8,
/** BSD whiteout. */
BFTW_WHT = 1 << 9,
/** An error occurred for this file. */
BFTW_ERROR = 1 << 10,
};
/**
* Convert a bfs_stat() mode to a bftw() typeflag.
*/
enum bftw_typeflag bftw_mode_typeflag(mode_t mode);
/**
* Possible visit occurrences.
*/
enum bftw_visit {
/** Pre-order visit. */
BFTW_PRE,
/** Post-order visit. */
BFTW_POST,
};
/**
* Data about the current file for the bftw() callback.
*/
struct BFTW {
/** The path to the file. */
const char *path;
/** The string offset of the filename. */
size_t nameoff;
/** The root path passed to bftw(). */
const char *root;
/** The depth of this file in the traversal. */
size_t depth;
/** Which visit this is. */
enum bftw_visit visit;
/** The file type. */
enum bftw_typeflag typeflag;
/** The errno that occurred, if typeflag == BFTW_ERROR. */
int error;
/** A bfs_stat() buffer; may be NULL if no stat() call was needed. */
const struct bfs_stat *statbuf;
/** A parent file descriptor for the *at() family of calls. */
int at_fd;
/** The path relative to atfd for the *at() family of calls. */
const char *at_path;
/** Appropriate flags (such as AT_SYMLINK_NOFOLLOW) for the *at() family of calls. */
int at_flags;
};
/**
* Walk actions returned by the bftw() callback.
*/
enum bftw_action {
/** Keep walking. */
BFTW_CONTINUE,
/** Skip this path's children. */
BFTW_SKIP_SUBTREE,
/** Stop walking. */
BFTW_STOP,
};
/**
* Callback function type for bftw().
*
* @param ftwbuf
* Data about the current file.
* @param ptr
* The pointer passed to bftw().
* @return
* An action value.
*/
typedef enum bftw_action bftw_callback(struct BFTW *ftwbuf, void *ptr);
/**
* Flags that control bftw() behavior.
*/
enum bftw_flags {
/** stat() each encountered file. */
BFTW_STAT = 1 << 0,
/** Attempt to recover from encountered errors. */
BFTW_RECOVER = 1 << 1,
/** Visit directories in post-order as well as pre-order. */
BFTW_DEPTH = 1 << 2,
/** If the initial path is a symbolic link, follow it. */
BFTW_COMFOLLOW = 1 << 3,
/** Follow all symbolic links. */
BFTW_LOGICAL = 1 << 4,
/** Detect directory cycles. */
BFTW_DETECT_CYCLES = 1 << 5,
/** Stay on the same filesystem. */
BFTW_XDEV = 1 << 6,
};
/**
* Structure for holding the arguments passed to bftw().
*/
struct bftw_args {
/** The callback to invoke. */
bftw_callback *callback;
/** A pointer which is passed to the callback. */
void *ptr;
/** The maximum number of file descriptors to keep open. */
int nopenfd;
/** Flags that control bftw() behaviour. */
enum bftw_flags flags;
/** The parsed mount table, if available. */
const struct bfs_mtab *mtab;
};
/**
* Breadth First Tree Walk (or Better File Tree Walk).
*
* Like ftw(3) and nftw(3), this function walks a directory tree recursively,
* and invokes a callback for each path it encounters. However, bftw() operates
* breadth-first.
*
* @param path
* The starting path.
* @param args
* The arguments that control the walk.
* @return
* 0 on success, or -1 on failure.
*/
int bftw(const char *path, const struct bftw_args *args);
#endif // BFS_BFTW_H
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