142 lines
6.0 KiB
C
142 lines
6.0 KiB
C
/*-
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* Copyright (c) 2003-2007 Tim Kientzle
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD: src/usr.bin/tar/tree.h,v 1.4 2008/11/27 05:49:52 kientzle Exp $
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*/
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/*-
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* A set of routines for traversing directory trees.
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* Similar in concept to the fts library, but with a few
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* important differences:
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* * Uses less memory. In particular, fts stores an entire directory
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* in memory at a time. This package only keeps enough subdirectory
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* information in memory to track the traversal. Information
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* about non-directories is discarded as soon as possible.
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* * Supports very deep logical traversals. The fts package
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* uses "non-chdir" approach for logical traversals. This
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* package does use a chdir approach for logical traversals
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* and can therefore handle pathnames much longer than PATH_MAX.
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* * Supports deep physical traversals "out of the box."
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* Due to the memory optimizations above, there's no need to
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* limit dir names to 32k.
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*/
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#include <sys/stat.h>
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#include <stdio.h>
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struct tree;
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/* Initiate/terminate a tree traversal. */
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struct tree *tree_open(const char * /* pathname */);
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void tree_close(struct tree *);
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/*
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* tree_next() returns Zero if there is no next entry, non-zero if
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* there is. Note that directories are visited three times.
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* Directories are always visited first as part of enumerating their
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* parent; that is a "regular" visit. If tree_descend() is invoked at
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* that time, the directory is added to a work list and will
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* subsequently be visited two more times: once just after descending
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* into the directory ("postdescent") and again just after ascending
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* back to the parent ("postascent").
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*
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* TREE_ERROR_DIR is returned if the descent failed (because the
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* directory couldn't be opened, for instance). This is returned
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* instead of TREE_POSTDESCENT/TREE_POSTASCENT. TREE_ERROR_DIR is not a
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* fatal error, but it does imply that the relevant subtree won't be
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* visited. TREE_ERROR_FATAL is returned for an error that left the
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* traversal completely hosed. Right now, this is only returned for
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* chdir() failures during ascent.
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*/
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#define TREE_REGULAR 1
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#define TREE_POSTDESCENT 2
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#define TREE_POSTASCENT 3
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#define TREE_ERROR_DIR -1
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#define TREE_ERROR_FATAL -2
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int tree_next(struct tree *);
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/* Errno value associated with the last traversal error. */
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int tree_errno(struct tree *);
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/*
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* Request that current entry be visited. If you invoke it on every
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* directory, you'll get a physical traversal. This is ignored if the
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* current entry isn't a directory or a link to a directory. So, if
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* you invoke this on every returned path, you'll get a full logical
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* traversal.
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*/
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void tree_descend(struct tree *);
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/*
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* Return information about the current entry.
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*/
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/* Current depth in the traversal. */
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int tree_current_depth(struct tree *);
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/*
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* The current full pathname, length of the full pathname, and a name
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* that can be used to access the file. Because tree does use chdir
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* extensively, the access path is almost never the same as the full
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* current path.
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*
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* TODO: Flesh out this interface to provide other information. In
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* particular, Windows can provide file size, mode, and some permission
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* information without invoking stat() at all.
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*
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* TODO: On platforms that support it, use openat()-style operations
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* to eliminate the chdir() operations entirely while still supporting
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* arbitrarily deep traversals. This makes access_path troublesome to
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* support, of course, which means we'll need a rich enough interface
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* that clients can function without it. (In particular, we'll need
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* tree_current_open() that returns an open file descriptor.)
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*
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* TODO: Provide tree_current_archive_entry().
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*/
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const char *tree_current_path(struct tree *);
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size_t tree_current_pathlen(struct tree *);
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const char *tree_current_access_path(struct tree *);
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/*
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* Request the lstat() or stat() data for the current path. Since the
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* tree package needs to do some of this anyway, and caches the
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* results, you should take advantage of it here if you need it rather
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* than make a redundant stat() or lstat() call of your own.
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*/
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const struct stat *tree_current_stat(struct tree *);
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const struct stat *tree_current_lstat(struct tree *);
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/* The following functions use tricks to avoid a certain number of
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* stat()/lstat() calls. */
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/* "is_physical_dir" is equivalent to S_ISDIR(tree_current_lstat()->st_mode) */
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int tree_current_is_physical_dir(struct tree *);
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/* "is_physical_link" is equivalent to S_ISLNK(tree_current_lstat()->st_mode) */
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int tree_current_is_physical_link(struct tree *);
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/* "is_dir" is equivalent to S_ISDIR(tree_current_stat()->st_mode) */
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int tree_current_is_dir(struct tree *);
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/* For testing/debugging: Dump the internal status to the given filehandle. */
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void tree_dump(struct tree *, FILE *);
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