Source / Include Folder (#88)

Moved Source Files Into `src` Folder

1 files changed, 0 insertions, 1494 deletions

diff --git a/bftw.c b/bftw.c
deleted file mode 100644
index 6f97bf6..0000000
--- a/bftw.c
+++ /dev/null
@@ -1,1494 +0,0 @@
-/****************************************************************************
- * bfs                                                                      *
- * Copyright (C) 2015-2022 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.           *
- ****************************************************************************/
-
-/**
- * The bftw() implementation consists of the following components:
- *
- * - struct bftw_file: A file that has been encountered during the traversal.
- *   They have reference-counted links to their parents in the directory tree.
- *
- * - struct bftw_cache: An LRU list of bftw_file's with open file descriptors,
- *   used for openat() to minimize the amount of path re-traversals.
- *
- * - struct bftw_queue: The queue of bftw_file's left to explore.  Implemented
- *   as a simple circular buffer.
- *
- * - struct bftw_state: Represents the current state of the traversal, allowing
- *   various helper functions to take fewer parameters.
- */
-
-#include "bftw.h"
-#include "dir.h"
-#include "darray.h"
-#include "dstring.h"
-#include "mtab.h"
-#include "stat.h"
-#include "trie.h"
-#include "util.h"
-#include <assert.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-/**
- * A file.
- */
-struct bftw_file {
-	/** The parent directory, if any. */
-	struct bftw_file *parent;
-	/** The root under which this file was found. */
-	struct bftw_file *root;
-	/** The next file in the queue, if any. */
-	struct bftw_file *next;
-
-	/** The previous file in the LRU list. */
-	struct bftw_file *lru_prev;
-	/** The next file in the LRU list. */
-	struct bftw_file *lru_next;
-
-	/** This file's depth in the walk. */
-	size_t depth;
-	/** Reference count. */
-	size_t refcount;
-
-	/** An open descriptor to this file, or -1. */
-	int fd;
-
-	/** This file's type, if known. */
-	enum bfs_type type;
-	/** The device number, for cycle detection. */
-	dev_t dev;
-	/** The inode number, for cycle detection. */
-	ino_t ino;
-
-	/** The offset of this file in the full path. */
-	size_t nameoff;
-	/** The length of the file's name. */
-	size_t namelen;
-	/** The file's name. */
-	char name[];
-};
-
-/**
- * A cache of open directories.
- */
-struct bftw_cache {
-	/** The head of the LRU list. */
-	struct bftw_file *head;
-	/** The insertion target for the LRU list. */
-	struct bftw_file *target;
-	/** The tail of the LRU list. */
-	struct bftw_file *tail;
-	/** The remaining capacity of the LRU list. */
-	size_t capacity;
-};
-
-/** Initialize a cache. */
-static void bftw_cache_init(struct bftw_cache *cache, size_t capacity) {
-	cache->head = NULL;
-	cache->target = NULL;
-	cache->tail = NULL;
-	cache->capacity = capacity;
-}
-
-/** Destroy a cache. */
-static void bftw_cache_destroy(struct bftw_cache *cache) {
-	assert(!cache->tail);
-	assert(!cache->target);
-	assert(!cache->head);
-}
-
-/** Add a bftw_file to the cache. */
-static void bftw_cache_add(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(cache->capacity > 0);
-	assert(file->fd >= 0);
-	assert(!file->lru_prev);
-	assert(!file->lru_next);
-
-	if (cache->target) {
-		file->lru_prev = cache->target;
-		file->lru_next = cache->target->lru_next;
-	} else {
-		file->lru_next = cache->head;
-	}
-
-	if (file->lru_prev) {
-		file->lru_prev->lru_next = file;
-	} else {
-		cache->head = file;
-	}
-
-	if (file->lru_next) {
-		file->lru_next->lru_prev = file;
-	} else {
-		cache->tail = file;
-	}
-
-	// Prefer to keep the root paths open by keeping them at the head of the list
-	if (file->depth == 0) {
-		cache->target = file;
-	}
-
-	--cache->capacity;
-}
-
-/** Remove a bftw_file from the cache. */
-static void bftw_cache_remove(struct bftw_cache *cache, struct bftw_file *file) {
-	if (cache->target == file) {
-		cache->target = file->lru_prev;
-	}
-
-	if (file->lru_prev) {
-		assert(cache->head != file);
-		file->lru_prev->lru_next = file->lru_next;
-	} else {
-		assert(cache->head == file);
-		cache->head = file->lru_next;
-	}
-
-	if (file->lru_next) {
-		assert(cache->tail != file);
-		file->lru_next->lru_prev = file->lru_prev;
-	} else {
-		assert(cache->tail == file);
-		cache->tail = file->lru_prev;
-	}
-
-	file->lru_prev = NULL;
-	file->lru_next = NULL;
-	++cache->capacity;
-}
-
-/** Mark a cache entry as recently used. */
-static void bftw_cache_use(struct bftw_cache *cache, struct bftw_file *file) {
-	bftw_cache_remove(cache, file);
-	bftw_cache_add(cache, file);
-}
-
-/** Close a bftw_file. */
-static void bftw_file_close(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(file->fd >= 0);
-
-	bftw_cache_remove(cache, file);
-
-	xclose(file->fd);
-	file->fd = -1;
-}
-
-/** Pop a directory from the cache. */
-static void bftw_cache_pop(struct bftw_cache *cache) {
-	assert(cache->tail);
-	bftw_file_close(cache, cache->tail);
-}
-
-/**
- * Shrink the cache, to recover from EMFILE.
- *
- * @param cache
- *         The cache in question.
- * @param saved
- *         A bftw_file that must be preserved.
- * @return
- *         0 if successfully shrunk, otherwise -1.
- */
-static int bftw_cache_shrink(struct bftw_cache *cache, const struct bftw_file *saved) {
-	struct bftw_file *file = cache->tail;
-	if (!file) {
-		return -1;
-	}
-
-	if (file == saved) {
-		file = file->lru_prev;
-		if (!file) {
-			return -1;
-		}
-	}
-
-	bftw_file_close(cache, file);
-	cache->capacity = 0;
-	return 0;
-}
-
-/** Compute the name offset of a child path. */
-static size_t bftw_child_nameoff(const struct bftw_file *parent) {
-	size_t ret = parent->nameoff + parent->namelen;
-	if (parent->name[parent->namelen - 1] != '/') {
-		++ret;
-	}
-	return ret;
-}
-
-/** Create a new bftw_file. */
-static struct bftw_file *bftw_file_new(struct bftw_file *parent, const char *name) {
-	size_t namelen = strlen(name);
-	size_t size = BFS_FLEX_SIZEOF(struct bftw_file, name, namelen + 1);
-
-	struct bftw_file *file = malloc(size);
-	if (!file) {
-		return NULL;
-	}
-
-	file->parent = parent;
-
-	if (parent) {
-		file->root = parent->root;
-		file->depth = parent->depth + 1;
-		file->nameoff = bftw_child_nameoff(parent);
-		++parent->refcount;
-	} else {
-		file->root = file;
-		file->depth = 0;
-		file->nameoff = 0;
-	}
-
-	file->next = NULL;
-
-	file->lru_prev = NULL;
-	file->lru_next = NULL;
-
-	file->refcount = 1;
-	file->fd = -1;
-
-	file->type = BFS_UNKNOWN;
-	file->dev = -1;
-	file->ino = -1;
-
-	file->namelen = namelen;
-	memcpy(file->name, name, namelen + 1);
-
-	return file;
-}
-
-/**
- * Open a bftw_file relative to another one.
- *
- * @param cache
- *         The cache to hold the file.
- * @param file
- *         The file to open.
- * @param base
- *         The base directory for the relative path (may be NULL).
- * @param at_fd
- *         The base file descriptor, AT_FDCWD if base == NULL.
- * @param at_path
- *         The relative path to the file.
- * @return
- *         The opened file descriptor, or negative on error.
- */
-static int bftw_file_openat(struct bftw_cache *cache, struct bftw_file *file, struct bftw_file *base, const char *at_path) {
-	assert(file->fd < 0);
-
-	int at_fd = AT_FDCWD;
-	if (base) {
-		bftw_cache_use(cache, base);
-		at_fd = base->fd;
-	}
-
-	int flags = O_RDONLY | O_CLOEXEC | O_DIRECTORY;
-	int fd = openat(at_fd, at_path, flags);
-
-	if (fd < 0 && errno == EMFILE) {
-		if (bftw_cache_shrink(cache, base) == 0) {
-			fd = openat(at_fd, at_path, flags);
-		}
-	}
-
-	if (fd >= 0) {
-		if (cache->capacity == 0) {
-			bftw_cache_pop(cache);
-		}
-
-		file->fd = fd;
-		bftw_cache_add(cache, file);
-	}
-
-	return fd;
-}
-
-/**
- * Open a bftw_file.
- *
- * @param cache
- *         The cache to hold the file.
- * @param file
- *         The file to open.
- * @param path
- *         The full path to the file.
- * @return
- *         The opened file descriptor, or negative on error.
- */
-static int bftw_file_open(struct bftw_cache *cache, struct bftw_file *file, const char *path) {
-	// Find the nearest open ancestor
-	struct bftw_file *base = file;
-	do {
-		base = base->parent;
-	} while (base && base->fd < 0);
-
-	const char *at_path = path;
-	if (base) {
-		at_path += bftw_child_nameoff(base);
-	}
-
-	int fd = bftw_file_openat(cache, file, base, at_path);
-	if (fd >= 0 || errno != ENAMETOOLONG) {
-		return fd;
-	}
-
-	// Handle ENAMETOOLONG by manually traversing the path component-by-component
-
-	// Use the ->next linked list to temporarily hold the reversed parent
-	// chain between base and file
-	struct bftw_file *cur;
-	for (cur = file; cur->parent != base; cur = cur->parent) {
-		cur->parent->next = cur;
-	}
-
-	// Open the files in the chain one by one
-	for (base = cur; base; base = base->next) {
-		fd = bftw_file_openat(cache, base, base->parent, base->name);
-		if (fd < 0 || base == file) {
-			break;
-		}
-	}
-
-	// Clear out the linked list
-	for (struct bftw_file *next = cur->next; cur != file; cur = next, next = next->next) {
-		cur->next = NULL;
-	}
-
-	return fd;
-}
-
-/**
- * Open a bftw_file as a directory.
- *
- * @param cache
- *         The cache to hold the file.
- * @param file
- *         The directory to open.
- * @param path
- *         The full path to the directory.
- * @return
- *         The opened directory, or NULL on error.
- */
-static struct bfs_dir *bftw_file_opendir(struct bftw_cache *cache, struct bftw_file *file, const char *path) {
-	int fd = bftw_file_open(cache, file, path);
-	if (fd < 0) {
-		return NULL;
-	}
-
-	return bfs_opendir(fd, NULL);
-}
-
-/** Free a bftw_file. */
-static void bftw_file_free(struct bftw_cache *cache, struct bftw_file *file) {
-	assert(file->refcount == 0);
-
-	if (file->fd >= 0) {
-		bftw_file_close(cache, file);
-	}
-
-	free(file);
-}
-
-/**
- * A queue of bftw_file's to examine.
- */
-struct bftw_queue {
-	/** The head of the queue. */
-	struct bftw_file *head;
-	/** The insertion target. */
-	struct bftw_file **target;
-};
-
-/** Initialize a bftw_queue. */
-static void bftw_queue_init(struct bftw_queue *queue) {
-	queue->head = NULL;
-	queue->target = &queue->head;
-}
-
-/** Add a file to a bftw_queue. */
-static void bftw_queue_push(struct bftw_queue *queue, struct bftw_file *file) {
-	assert(file->next == NULL);
-
-	file->next = *queue->target;
-	*queue->target = file;
-	queue->target = &file->next;
-}
-
-/** Pop the next file from the head of the queue. */
-static struct bftw_file *bftw_queue_pop(struct bftw_queue *queue) {
-	struct bftw_file *file = queue->head;
-	queue->head = file->next;
-	file->next = NULL;
-	if (queue->target == &file->next) {
-		queue->target = &queue->head;
-	}
-	return file;
-}
-
-/** The split phase of mergesort. */
-static struct bftw_file **bftw_sort_split(struct bftw_file **head, struct bftw_file **tail) {
-	struct bftw_file **tortoise = head, **hare = head;
-
-	while (*hare != *tail) {
-		tortoise = &(*tortoise)->next;
-		hare = &(*hare)->next;
-		if (*hare != *tail) {
-			hare = &(*hare)->next;
-		}
-	}
-
-	return tortoise;
-}
-
-/** The merge phase of mergesort. */
-static struct bftw_file **bftw_sort_merge(struct bftw_file **head, struct bftw_file **mid, struct bftw_file **tail) {
-	struct bftw_file *left = *head, *right = *mid, *end = *tail;
-	*mid = NULL;
-	*tail = NULL;
-
-	while (left || right) {
-		struct bftw_file *next;
-		if (left && (!right || strcoll(left->name, right->name) <= 0)) {
-			next = left;
-			left = left->next;
-		} else {
-			next = right;
-			right = right->next;
-		}
-
-		*head = next;
-		head = &next->next;
-	}
-
-	*head = end;
-	return head;
-}
-
-/**
- * Sort a (sub-)list of files.
- *
- * @param head
- *         The head of the (sub-)list to sort.
- * @param tail
- *         The tail of the (sub-)list to sort.
- * @return
- *         The new tail of the (sub-)list.
- */
-static struct bftw_file **bftw_sort_files(struct bftw_file **head, struct bftw_file **tail) {
-	struct bftw_file **mid = bftw_sort_split(head, tail);
-	if (*mid == *head || *mid == *tail) {
-		return tail;
-	}
-
-	mid = bftw_sort_files(head, mid);
-	tail = bftw_sort_files(mid, tail);
-
-	return bftw_sort_merge(head, mid, tail);
-}
-
-/**
- * Holds the current state of the bftw() traversal.
- */
-struct bftw_state {
-	/** bftw() callback. */
-	bftw_callback *callback;
-	/** bftw() callback data. */
-	void *ptr;
-	/** bftw() flags. */
-	enum bftw_flags flags;
-	/** Search strategy. */
-	enum bftw_strategy strategy;
-	/** The mount table. */
-	const struct bfs_mtab *mtab;
-
-	/** The appropriate errno value, if any. */
-	int error;
-
-	/** The cache of open directories. */
-	struct bftw_cache cache;
-	/** The queue of directories left to explore. */
-	struct bftw_queue queue;
-	/** The start of the current batch of files. */
-	struct bftw_file **batch;
-
-	/** The current path. */
-	char *path;
-	/** The current file. */
-	struct bftw_file *file;
-	/** The previous file. */
-	struct bftw_file *previous;
-
-	/** The currently open directory. */
-	struct bfs_dir *dir;
-	/** The current directory entry. */
-	struct bfs_dirent *de;
-	/** Storage for the directory entry. */
-	struct bfs_dirent de_storage;
-	/** Any error encountered while reading the directory. */
-	int direrror;
-
-	/** Extra data about the current file. */
-	struct BFTW ftwbuf;
-};
-
-/**
- * Initialize the bftw() state.
- */
-static int bftw_state_init(struct bftw_state *state, const struct bftw_args *args) {
-	state->callback = args->callback;
-	state->ptr = args->ptr;
-	state->flags = args->flags;
-	state->strategy = args->strategy;
-	state->mtab = args->mtab;
-
-	state->error = 0;
-
-	if (args->nopenfd < 1) {
-		errno = EMFILE;
-		return -1;
-	}
-
-	state->path = dstralloc(0);
-	if (!state->path) {
-		return -1;
-	}
-
-	bftw_cache_init(&state->cache, args->nopenfd);
-	bftw_queue_init(&state->queue);
-	state->batch = NULL;
-
-	state->file = NULL;
-	state->previous = NULL;
-
-	state->dir = NULL;
-	state->de = NULL;
-	state->direrror = 0;
-
-	return 0;
-}
-
-/** Cached bfs_stat(). */
-static const struct bfs_stat *bftw_stat_impl(struct BFTW *ftwbuf, struct bftw_stat *cache, enum bfs_stat_flags flags) {
-	if (!cache->buf) {
-		if (cache->error) {
-			errno = cache->error;
-		} else if (bfs_stat(ftwbuf->at_fd, ftwbuf->at_path, flags, &cache->storage) == 0) {
-			cache->buf = &cache->storage;
-		} else {
-			cache->error = errno;
-		}
-	}
-
-	return cache->buf;
-}
-
-const struct bfs_stat *bftw_stat(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
-	struct BFTW *mutbuf = (struct BFTW *)ftwbuf;
-	const struct bfs_stat *ret;
-
-	if (flags & BFS_STAT_NOFOLLOW) {
-		ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
-		if (ret && !S_ISLNK(ret->mode) && !mutbuf->stat_cache.buf) {
-			// Non-link, so share stat info
-			mutbuf->stat_cache.buf = ret;
-		}
-	} else {
-		ret = bftw_stat_impl(mutbuf, &mutbuf->stat_cache, BFS_STAT_FOLLOW);
-		if (!ret && (flags & BFS_STAT_TRYFOLLOW) && is_nonexistence_error(errno)) {
-			ret = bftw_stat_impl(mutbuf, &mutbuf->lstat_cache, BFS_STAT_NOFOLLOW);
-		}
-	}
-
-	return ret;
-}
-
-const struct bfs_stat *bftw_cached_stat(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
-	if (flags & BFS_STAT_NOFOLLOW) {
-		return ftwbuf->lstat_cache.buf;
-	} else if (ftwbuf->stat_cache.buf) {
-		return ftwbuf->stat_cache.buf;
-	} else if ((flags & BFS_STAT_TRYFOLLOW) && is_nonexistence_error(ftwbuf->stat_cache.error)) {
-		return ftwbuf->lstat_cache.buf;
-	} else {
-		return NULL;
-	}
-}
-
-enum bfs_type bftw_type(const struct BFTW *ftwbuf, enum bfs_stat_flags flags) {
-	if (flags & BFS_STAT_NOFOLLOW) {
-		if (ftwbuf->type == BFS_LNK || (ftwbuf->stat_flags & BFS_STAT_NOFOLLOW)) {
-			return ftwbuf->type;
-		}
-	} else if (flags & BFS_STAT_TRYFOLLOW) {
-		if (ftwbuf->type != BFS_LNK || (ftwbuf->stat_flags & BFS_STAT_TRYFOLLOW)) {
-			return ftwbuf->type;
-		}
-	} else {
-		if (ftwbuf->type != BFS_LNK) {
-			return ftwbuf->type;
-		} else if (ftwbuf->stat_flags & BFS_STAT_TRYFOLLOW) {
-			return BFS_ERROR;
-		}
-	}
-
-	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, flags);
-	if (statbuf) {
-		return bfs_mode_to_type(statbuf->mode);
-	} else {
-		return BFS_ERROR;
-	}
-}
-
-/**
- * Update the path for the current file.
- */
-static int bftw_update_path(struct bftw_state *state, const char *name) {
-	const struct bftw_file *file = state->file;
-	size_t length = file ? file->nameoff + file->namelen : 0;
-
-	assert(dstrlen(state->path) >= length);
-	dstresize(&state->path, length);
-
-	if (name) {
-		if (length > 0 && state->path[length - 1] != '/') {
-			if (dstrapp(&state->path, '/') != 0) {
-				return -1;
-			}
-		}
-		if (dstrcat(&state->path, name) != 0) {
-			return -1;
-		}
-	}
-
-	return 0;
-}
-
-/** Check if a stat() call is needed for this visit. */
-static bool bftw_need_stat(const struct bftw_state *state) {
-	if (state->flags & BFTW_STAT) {
-		return true;
-	}
-
-	const struct BFTW *ftwbuf = &state->ftwbuf;
-	if (ftwbuf->type == BFS_UNKNOWN) {
-		return true;
-	}
-
-	if (ftwbuf->type == BFS_LNK && !(ftwbuf->stat_flags & BFS_STAT_NOFOLLOW)) {
-		return true;
-	}
-
-	if (ftwbuf->type == BFS_DIR) {
-		if (state->flags & (BFTW_DETECT_CYCLES | BFTW_SKIP_MOUNTS | BFTW_PRUNE_MOUNTS)) {
-			return true;
-		}
-#if __linux__
-	} else if (state->mtab) {
-		// Linux fills in d_type from the underlying inode, even when
-		// the directory entry is a bind mount point.  In that case, we
-		// need to stat() to get the correct type.  We don't need to
-		// check for directories because they can only be mounted over
-		// by other directories.
-		if (bfs_might_be_mount(state->mtab, ftwbuf->path)) {
-			return true;
-		}
-#endif
-	}
-
-	return false;
-}
-
-/** Initialize bftw_stat cache. */
-static void bftw_stat_init(struct bftw_stat *cache) {
-	cache->buf = NULL;
-	cache->error = 0;
-}
-
-/**
- * Open a file if necessary.
- *
- * @param file
- *         The file to open.
- * @param path
- *         The path to that file or one of its descendants.
- * @return
- *         The opened file descriptor, or -1 on error.
- */
-static int bftw_ensure_open(struct bftw_cache *cache, struct bftw_file *file, const char *path) {
-	int ret = file->fd;
-
-	if (ret < 0) {
-		char *copy = strndup(path, file->nameoff + file->namelen);
-		if (!copy) {
-			return -1;
-		}
-
-		ret = bftw_file_open(cache, file, copy);
-		free(copy);
-	}
-
-	return ret;
-}
-
-/**
- * Initialize the buffers with data about the current path.
- */
-static void bftw_init_ftwbuf(struct bftw_state *state, enum bftw_visit visit) {
-	struct bftw_file *file = state->file;
-	const struct bfs_dirent *de = state->de;
-
-	struct BFTW *ftwbuf = &state->ftwbuf;
-	ftwbuf->path = state->path;
-	ftwbuf->root = file ? file->root->name : ftwbuf->path;
-	ftwbuf->depth = 0;
-	ftwbuf->visit = visit;
-	ftwbuf->type = BFS_UNKNOWN;
-	ftwbuf->error = state->direrror;
-	ftwbuf->at_fd = AT_FDCWD;
-	ftwbuf->at_path = ftwbuf->path;
-	ftwbuf->stat_flags = BFS_STAT_NOFOLLOW;
-	bftw_stat_init(&ftwbuf->lstat_cache);
-	bftw_stat_init(&ftwbuf->stat_cache);
-
-	struct bftw_file *parent = NULL;
-	if (de) {
-		parent = file;
-		ftwbuf->depth = file->depth + 1;
-		ftwbuf->type = de->type;
-		ftwbuf->nameoff = bftw_child_nameoff(file);
-	} else if (file) {
-		parent = file->parent;
-		ftwbuf->depth = file->depth;
-		ftwbuf->type = file->type;
-		ftwbuf->nameoff = file->nameoff;
-	}
-
-	if (parent) {
-		// Try to ensure the immediate parent is open, to avoid ENAMETOOLONG
-		if (bftw_ensure_open(&state->cache, parent, state->path) >= 0) {
-			ftwbuf->at_fd = parent->fd;
-			ftwbuf->at_path += ftwbuf->nameoff;
-		} else {
-			ftwbuf->error = errno;
-		}
-	}
-
-	if (ftwbuf->depth == 0) {
-		// Compute the name offset for root paths like "foo/bar"
-		ftwbuf->nameoff = xbasename(ftwbuf->path) - ftwbuf->path;
-	}
-
-	if (ftwbuf->error != 0) {
-		ftwbuf->type = BFS_ERROR;
-		return;
-	}
-
-	int follow_flags = BFTW_FOLLOW_ALL;
-	if (ftwbuf->depth == 0) {
-		follow_flags |= BFTW_FOLLOW_ROOTS;
-	}
-	bool follow = state->flags & follow_flags;
-	if (follow) {
-		ftwbuf->stat_flags = BFS_STAT_TRYFOLLOW;
-	}
-
-	const struct bfs_stat *statbuf = NULL;
-	if (bftw_need_stat(state)) {
-		statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
-		if (statbuf) {
-			ftwbuf->type = bfs_mode_to_type(statbuf->mode);
-		} else {
-			ftwbuf->type = BFS_ERROR;
-			ftwbuf->error = errno;
-			return;
-		}
-	}
-
-	if (ftwbuf->type == BFS_DIR && (state->flags & BFTW_DETECT_CYCLES)) {
-		for (const struct bftw_file *ancestor = parent; ancestor; ancestor = ancestor->parent) {
-			if (ancestor->dev == statbuf->dev && ancestor->ino == statbuf->ino) {
-				ftwbuf->type = BFS_ERROR;
-				ftwbuf->error = ELOOP;
-				return;
-			}
-		}
-	}
-}
-
-/** Check if the current file is a mount point. */
-static bool bftw_is_mount(struct bftw_state *state, const char *name) {
-	const struct bftw_file *file = state->file;
-	if (!file) {
-		return false;
-	}
-
-	const struct bftw_file *parent = name ? file : file->parent;
-	if (!parent) {
-		return false;
-	}
-
-	const struct BFTW *ftwbuf = &state->ftwbuf;
-	const struct bfs_stat *statbuf = bftw_stat(ftwbuf, ftwbuf->stat_flags);
-	return statbuf && statbuf->dev != parent->dev;
-}
-
-/** Fill file identity information from an ftwbuf. */
-static void bftw_fill_id(struct bftw_file *file, const struct BFTW *ftwbuf) {
-	const struct bfs_stat *statbuf = ftwbuf->stat_cache.buf;
-	if (!statbuf || (ftwbuf->stat_flags & BFS_STAT_NOFOLLOW)) {
-		statbuf = ftwbuf->lstat_cache.buf;
-	}
-	if (statbuf) {
-		file->dev = statbuf->dev;
-		file->ino = statbuf->ino;
-	}
-}
-
-/**
- * Visit a path, invoking the callback.
- */
-static enum bftw_action bftw_visit(struct bftw_state *state, const char *name, enum bftw_visit visit) {
-	if (bftw_update_path(state, name) != 0) {
-		state->error = errno;
-		return BFTW_STOP;
-	}
-
-	const struct BFTW *ftwbuf = &state->ftwbuf;
-	bftw_init_ftwbuf(state, visit);
-
-	// Never give the callback BFS_ERROR unless BFTW_RECOVER is specified
-	if (ftwbuf->type == BFS_ERROR && !(state->flags & BFTW_RECOVER)) {
-		state->error = ftwbuf->error;
-		return BFTW_STOP;
-	}
-
-	if ((state->flags & BFTW_SKIP_MOUNTS) && bftw_is_mount(state, name)) {
-		return BFTW_PRUNE;
-	}
-
-	enum bftw_action ret = state->callback(ftwbuf, state->ptr);
-	switch (ret) {
-	case BFTW_CONTINUE:
-		break;
-	case BFTW_PRUNE:
-	case BFTW_STOP:
-		goto done;
-	default:
-		state->error = EINVAL;
-		return BFTW_STOP;
-	}
-
-	if (visit != BFTW_PRE || ftwbuf->type != BFS_DIR) {
-		ret = BFTW_PRUNE;
-		goto done;
-	}
-
-	if ((state->flags & BFTW_PRUNE_MOUNTS) && bftw_is_mount(state, name)) {
-		ret = BFTW_PRUNE;
-		goto done;
-	}
-
-done:
-	if (state->file && !name) {
-		bftw_fill_id(state->file, ftwbuf);
-	}
-
-	return ret;
-}
-
-/**
- * Push a new file onto the queue.
- */
-static int bftw_push(struct bftw_state *state, const char *name, bool fill_id) {
-	struct bftw_file *parent = state->file;
-	struct bftw_file *file = bftw_file_new(parent, name);
-	if (!file) {
-		state->error = errno;
-		return -1;
-	}
-
-	if (state->de) {
-		file->type = state->de->type;
-	}
-
-	if (fill_id) {
-		bftw_fill_id(file, &state->ftwbuf);
-	}
-
-	bftw_queue_push(&state->queue, file);
-
-	return 0;
-}
-
-/**
- * Build the path to the current file.
- */
-static int bftw_build_path(struct bftw_state *state) {
-	const struct bftw_file *file = state->file;
-
-	size_t pathlen = file->nameoff + file->namelen;
-	if (dstresize(&state->path, pathlen) != 0) {
-		state->error = errno;
-		return -1;
-	}
-
-	// Try to find a common ancestor with the existing path
-	const struct bftw_file *ancestor = state->previous;
-	while (ancestor && ancestor->depth > file->depth) {
-		ancestor = ancestor->parent;
-	}
-
-	// Build the path backwards
-	while (file && file != ancestor) {
-		if (file->nameoff > 0) {
-			state->path[file->nameoff - 1] = '/';
-		}
-		memcpy(state->path + file->nameoff, file->name, file->namelen);
-
-		if (ancestor && ancestor->depth == file->depth) {
-			ancestor = ancestor->parent;
-		}
-		file = file->parent;
-	}
-
-	state->previous = state->file;
-	return 0;
-}
-
-/**
- * Pop the next file from the queue.
- */
-static int bftw_pop(struct bftw_state *state) {
-	if (!state->queue.head) {
-		return 0;
-	}
-
-	state->file = bftw_queue_pop(&state->queue);
-
-	if (bftw_build_path(state) != 0) {
-		return -1;
-	}
-
-	return 1;
-}
-
-/**
- * Open the current directory.
- */
-static void bftw_opendir(struct bftw_state *state) {
-	assert(!state->dir);
-	assert(!state->de);
-
-	state->direrror = 0;
-
-	state->dir = bftw_file_opendir(&state->cache, state->file, state->path);
-	if (!state->dir) {
-		state->direrror = errno;
-	}
-}
-
-/**
- * Read an entry from the current directory.
- */
-static int bftw_readdir(struct bftw_state *state) {
-	if (!state->dir) {
-		return -1;
-	}
-
-	int ret = bfs_readdir(state->dir, &state->de_storage);
-	if (ret > 0) {
-		state->de = &state->de_storage;
-	} else if (ret == 0) {
-		state->de = NULL;
-	} else {
-		state->de = NULL;
-		state->direrror = errno;
-	}
-
-	return ret;
-}
-
-/**
- * Flags controlling which files get visited when done with a directory.
- */
-enum bftw_gc_flags {
-	/** Don't visit anything. */
-	BFTW_VISIT_NONE = 0,
-	/** Visit the file itself. */
-	BFTW_VISIT_FILE = 1 << 0,
-	/** Visit the file's ancestors. */
-	BFTW_VISIT_PARENTS = 1 << 1,
-	/** Visit both the file and its ancestors. */
-	BFTW_VISIT_ALL = BFTW_VISIT_FILE | BFTW_VISIT_PARENTS,
-};
-
-/**
- * Close the current directory.
- */
-static enum bftw_action bftw_closedir(struct bftw_state *state, enum bftw_gc_flags flags) {
-	struct bftw_file *file = state->file;
-	enum bftw_action ret = BFTW_CONTINUE;
-
-	if (state->dir) {
-		assert(file->fd >= 0);
-
-		if (file->refcount > 1) {
-			// Keep the fd around if any subdirectories exist
-			file->fd = bfs_freedir(state->dir);
-		} else {
-			bfs_closedir(state->dir);
-			file->fd = -1;
-		}
-
-		if (file->fd < 0) {
-			bftw_cache_remove(&state->cache, file);
-		}
-	}
-
-	state->de = NULL;
-	state->dir = NULL;
-
-	if (state->direrror != 0) {
-		if (flags & BFTW_VISIT_FILE) {
-			ret = bftw_visit(state, NULL, BFTW_PRE);
-		} else {
-			state->error = state->direrror;
-		}
-		state->direrror = 0;
-	}
-
-	return ret;
-}
-
-/**
- * Finalize and free a file we're done with.
- */
-static enum bftw_action bftw_gc_file(struct bftw_state *state, enum bftw_gc_flags flags) {
-	enum bftw_action ret = BFTW_CONTINUE;
-
-	if (!(state->flags & BFTW_POST_ORDER)) {
-		flags = 0;
-	}
-	bool visit = flags & BFTW_VISIT_FILE;
-
-	while (state->file) {
-		struct bftw_file *file = state->file;
-		if (--file->refcount > 0) {
-			state->file = NULL;
-			break;
-		}
-
-		if (visit && bftw_visit(state, NULL, BFTW_POST) == BFTW_STOP) {
-			ret = BFTW_STOP;
-			flags &= ~BFTW_VISIT_PARENTS;
-		}
-		visit = flags & BFTW_VISIT_PARENTS;
-
-		struct bftw_file *parent = file->parent;
-		if (state->previous == file) {
-			state->previous = parent;
-		}
-		bftw_file_free(&state->cache, file);
-		state->file = parent;
-	}
-
-	return ret;
-}
-
-/**
- * Drain all the entries from a bftw_queue.
- */
-static void bftw_drain_queue(struct bftw_state *state, struct bftw_queue *queue) {
-	while (queue->head) {
-		state->file = bftw_queue_pop(queue);
-		bftw_gc_file(state, BFTW_VISIT_NONE);
-	}
-}
-
-/**
- * Dispose of the bftw() state.
- *
- * @return
- *         The bftw() return value.
- */
-static int bftw_state_destroy(struct bftw_state *state) {
-	dstrfree(state->path);
-
-	bftw_closedir(state, BFTW_VISIT_NONE);
-
-	bftw_gc_file(state, BFTW_VISIT_NONE);
-	bftw_drain_queue(state, &state->queue);
-
-	bftw_cache_destroy(&state->cache);
-
-	errno = state->error;
-	return state->error ? -1 : 0;
-}
-
-/** Start a batch of files. */
-static void bftw_batch_start(struct bftw_state *state) {
-	if (state->strategy == BFTW_DFS) {
-		state->queue.target = &state->queue.head;
-	}
-	state->batch = state->queue.target;
-}
-
-/** Finish adding a batch of files. */
-static void bftw_batch_finish(struct bftw_state *state) {
-	if (state->flags & BFTW_SORT) {
-		state->queue.target = bftw_sort_files(state->batch, state->queue.target);
-	}
-}
-
-/**
- * Streaming mode: visit files as they are encountered.
- */
-static int bftw_stream(const struct bftw_args *args) {
-	struct bftw_state state;
-	if (bftw_state_init(&state, args) != 0) {
-		return -1;
-	}
-
-	assert(!(state.flags & (BFTW_SORT | BFTW_BUFFER)));
-
-	bftw_batch_start(&state);
-	for (size_t i = 0; i < args->npaths; ++i) {
-		const char *path = args->paths[i];
-
-		switch (bftw_visit(&state, path, BFTW_PRE)) {
-		case BFTW_CONTINUE:
-			break;
-		case BFTW_PRUNE:
-			continue;
-		case BFTW_STOP:
-			goto done;
-		}
-
-		if (bftw_push(&state, path, true) != 0) {
-			goto done;
-		}
-	}
-	bftw_batch_finish(&state);
-
-	while (bftw_pop(&state) > 0) {
-		bftw_opendir(&state);
-
-		bftw_batch_start(&state);
-		while (bftw_readdir(&state) > 0) {
-			const char *name = state.de->name;
-
-			switch (bftw_visit(&state, name, BFTW_PRE)) {
-			case BFTW_CONTINUE:
-				break;
-			case BFTW_PRUNE:
-				continue;
-			case BFTW_STOP:
-				goto done;
-			}
-
-			if (bftw_push(&state, name, true) != 0) {
-				goto done;
-			}
-		}
-		bftw_batch_finish(&state);
-
-		if (bftw_closedir(&state, BFTW_VISIT_ALL) == BFTW_STOP) {
-			goto done;
-		}
-		if (bftw_gc_file(&state, BFTW_VISIT_ALL) == BFTW_STOP) {
-			goto done;
-		}
-	}
-
-done:
-	return bftw_state_destroy(&state);
-}
-
-/**
- * Batching mode: queue up all children before visiting them.
- */
-static int bftw_batch(const struct bftw_args *args) {
-	struct bftw_state state;
-	if (bftw_state_init(&state, args) != 0) {
-		return -1;
-	}
-
-	bftw_batch_start(&state);
-	for (size_t i = 0; i < args->npaths; ++i) {
-		if (bftw_push(&state, args->paths[i], false) != 0) {
-			goto done;
-		}
-	}
-	bftw_batch_finish(&state);
-
-	while (bftw_pop(&state) > 0) {
-		enum bftw_gc_flags gcflags = BFTW_VISIT_ALL;
-
-		switch (bftw_visit(&state, NULL, BFTW_PRE)) {
-		case BFTW_CONTINUE:
-			break;
-		case BFTW_PRUNE:
-			gcflags &= ~BFTW_VISIT_FILE;
-			goto next;
-		case BFTW_STOP:
-			goto done;
-		}
-
-		bftw_opendir(&state);
-
-		bftw_batch_start(&state);
-		while (bftw_readdir(&state) > 0) {
-			if (bftw_push(&state, state.de->name, false) != 0) {
-				goto done;
-			}
-		}
-		bftw_batch_finish(&state);
-
-		if (bftw_closedir(&state, gcflags) == BFTW_STOP) {
-			goto done;
-		}
-
-	next:
-		if (bftw_gc_file(&state, gcflags) == BFTW_STOP) {
-			goto done;
-		}
-	}
-
-done:
-	return bftw_state_destroy(&state);
-}
-
-/** Select bftw_stream() or bftw_batch() appropriately. */
-static int bftw_auto(const struct bftw_args *args) {
-	if (args->flags & (BFTW_SORT | BFTW_BUFFER)) {
-		return bftw_batch(args);
-	} else {
-		return bftw_stream(args);
-	}
-}
-
-/**
- * Iterative deepening search state.
- */
-struct bftw_ids_state {
-	/** The wrapped callback. */
-	bftw_callback *delegate;
-	/** The wrapped callback arguments. */
-	void *ptr;
-	/** Which visit this search corresponds to. */
-	enum bftw_visit visit;
-	/** Whether to override the bftw_visit. */
-	bool force_visit;
-	/** The current minimum depth (inclusive). */
-	size_t min_depth;
-	/** The current maximum depth (exclusive). */
-	size_t max_depth;
-	/** The set of pruned paths. */
-	struct trie pruned;
-	/** An error code to report. */
-	int error;
-	/** Whether the bottom has been found. */
-	bool bottom;
-	/** Whether to quit the search. */
-	bool quit;
-};
-
-/** Iterative deepening callback function. */
-static enum bftw_action bftw_ids_callback(const struct BFTW *ftwbuf, void *ptr) {
-	struct bftw_ids_state *state = ptr;
-
-	if (state->force_visit) {
-		struct BFTW *mutbuf = (struct BFTW *)ftwbuf;
-		mutbuf->visit = state->visit;
-	}
-
-	if (ftwbuf->type == BFS_ERROR) {
-		if (ftwbuf->depth + 1 >= state->min_depth) {
-			return state->delegate(ftwbuf, state->ptr);
-		} else {
-			return BFTW_PRUNE;
-		}
-	}
-
-	if (ftwbuf->depth < state->min_depth) {
-		if (trie_find_str(&state->pruned, ftwbuf->path)) {
-			return BFTW_PRUNE;
-		} else {
-			return BFTW_CONTINUE;
-		}
-	} else if (state->visit == BFTW_POST) {
-		if (trie_find_str(&state->pruned, ftwbuf->path)) {
-			return BFTW_PRUNE;
-		}
-	}
-
-	enum bftw_action ret = BFTW_CONTINUE;
-	if (ftwbuf->visit == state->visit) {
-		ret = state->delegate(ftwbuf, state->ptr);
-	}
-
-	switch (ret) {
-	case BFTW_CONTINUE:
-		if (ftwbuf->type == BFS_DIR && ftwbuf->depth + 1 >= state->max_depth) {
-			state->bottom = false;
-			ret = BFTW_PRUNE;
-		}
-		break;
-	case BFTW_PRUNE:
-		if (ftwbuf->type == BFS_DIR) {
-			if (!trie_insert_str(&state->pruned, ftwbuf->path)) {
-				state->error = errno;
-				state->quit = true;
-				ret = BFTW_STOP;
-			}
-		}
-		break;
-	case BFTW_STOP:
-		state->quit = true;
-		break;
-	}
-
-	return ret;
-}
-
-/** Initialize iterative deepening state. */
-static void bftw_ids_init(const struct bftw_args *args, struct bftw_ids_state *state, struct bftw_args *ids_args) {
-	state->delegate = args->callback;
-	state->ptr = args->ptr;
-	state->visit = BFTW_PRE;
-	state->force_visit = false;
-	state->min_depth = 0;
-	state->max_depth = 1;
-	trie_init(&state->pruned);
-	state->error = 0;
-	state->bottom = false;
-	state->quit = false;
-
-	*ids_args = *args;
-	ids_args->callback = bftw_ids_callback;
-	ids_args->ptr = state;
-	ids_args->flags &= ~BFTW_POST_ORDER;
-	ids_args->strategy = BFTW_DFS;
-}
-
-/** Finish an iterative deepening search. */
-static int bftw_ids_finish(struct bftw_ids_state *state) {
-	int ret = 0;
-
-	if (state->error) {
-		ret = -1;
-	} else {
-		state->error = errno;
-	}
-
-	trie_destroy(&state->pruned);
-
-	errno = state->error;
-	return ret;
-}
-
-/**
- * Iterative deepening bftw() wrapper.
- */
-static int bftw_ids(const struct bftw_args *args) {
-	struct bftw_ids_state state;
-	struct bftw_args ids_args;
-	bftw_ids_init(args, &state, &ids_args);
-
-	while (!state.quit && !state.bottom) {
-		state.bottom = true;
-
-		if (bftw_auto(&ids_args) != 0) {
-			state.error = errno;
-			state.quit = true;
-		}
-
-		++state.min_depth;
-		++state.max_depth;
-	}
-
-	if (args->flags & BFTW_POST_ORDER) {
-		state.visit = BFTW_POST;
-		state.force_visit = true;
-
-		while (!state.quit && state.min_depth > 0) {
-			--state.max_depth;
-			--state.min_depth;
-
-			if (bftw_auto(&ids_args) != 0) {
-				state.error = errno;
-				state.quit = true;
-			}
-		}
-	}
-
-	return bftw_ids_finish(&state);
-}
-
-/**
- * Exponential deepening bftw() wrapper.
- */
-static int bftw_eds(const struct bftw_args *args) {
-	struct bftw_ids_state state;
-	struct bftw_args ids_args;
-	bftw_ids_init(args, &state, &ids_args);
-
-	while (!state.quit && !state.bottom) {
-		state.bottom = true;
-
-		if (bftw_auto(&ids_args) != 0) {
-			state.error = errno;
-			state.quit = true;
-		}
-
-		state.min_depth = state.max_depth;
-		state.max_depth *= 2;
-	}
-
-	if (!state.quit && (args->flags & BFTW_POST_ORDER)) {
-		state.visit = BFTW_POST;
-		state.min_depth = 0;
-		ids_args.flags |= BFTW_POST_ORDER;
-
-		if (bftw_auto(&ids_args) != 0) {
-			state.error = errno;
-		}
-	}
-
-	return bftw_ids_finish(&state);
-}
-
-int bftw(const struct bftw_args *args) {
-	switch (args->strategy) {
-	case BFTW_BFS:
-		return bftw_auto(args);
-	case BFTW_DFS:
-		return bftw_batch(args);
-	case BFTW_IDS:
-		return bftw_ids(args);
-	case BFTW_EDS:
-		return bftw_eds(args);
-	}
-
-	errno = EINVAL;
-	return -1;
-}