summaryrefslogtreecommitdiffstats
path: root/dir-iterator.c
blob: 3764dd81a185b296a5d4c0a9fc8c0ae2bd4085ec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
#include "cache.h"
#include "dir.h"
#include "iterator.h"
#include "dir-iterator.h"

struct dir_iterator_level {
	DIR *dir;

	/*
	 * The length of the directory part of path at this level
	 * (including a trailing '/'):
	 */
	size_t prefix_len;
};

/*
 * The full data structure used to manage the internal directory
 * iteration state. It includes members that are not part of the
 * public interface.
 */
struct dir_iterator_int {
	struct dir_iterator base;

	/*
	 * The number of levels currently on the stack. After the first
	 * call to dir_iterator_begin(), if it succeeds to open the
	 * first level's dir, this will always be at least 1. Then,
	 * when it comes to zero the iteration is ended and this
	 * struct is freed.
	 */
	size_t levels_nr;

	/* The number of levels that have been allocated on the stack */
	size_t levels_alloc;

	/*
	 * A stack of levels. levels[0] is the uppermost directory
	 * that will be included in this iteration.
	 */
	struct dir_iterator_level *levels;

	/* Combination of flags for this dir-iterator */
	unsigned int flags;
};

/*
 * Push a level in the iter stack and initialize it with information from
 * the directory pointed by iter->base->path. It is assumed that this
 * strbuf points to a valid directory path. Return 0 on success and -1
 * otherwise, setting errno accordingly and leaving the stack unchanged.
 */
static int push_level(struct dir_iterator_int *iter)
{
	struct dir_iterator_level *level;

	ALLOC_GROW(iter->levels, iter->levels_nr + 1, iter->levels_alloc);
	level = &iter->levels[iter->levels_nr++];

	if (!is_dir_sep(iter->base.path.buf[iter->base.path.len - 1]))
		strbuf_addch(&iter->base.path, '/');
	level->prefix_len = iter->base.path.len;

	level->dir = opendir(iter->base.path.buf);
	if (!level->dir) {
		int saved_errno = errno;
		if (errno != ENOENT) {
			warning_errno("error opening directory '%s'",
				      iter->base.path.buf);
		}
		iter->levels_nr--;
		errno = saved_errno;
		return -1;
	}

	return 0;
}

/*
 * Pop the top level on the iter stack, releasing any resources associated
 * with it. Return the new value of iter->levels_nr.
 */
static int pop_level(struct dir_iterator_int *iter)
{
	struct dir_iterator_level *level =
		&iter->levels[iter->levels_nr - 1];

	if (level->dir && closedir(level->dir))
		warning_errno("error closing directory '%s'",
			      iter->base.path.buf);
	level->dir = NULL;

	return --iter->levels_nr;
}

/*
 * Populate iter->base with the necessary information on the next iteration
 * entry, represented by the given dirent de. Return 0 on success and -1
 * otherwise, setting errno accordingly.
 */
static int prepare_next_entry_data(struct dir_iterator_int *iter,
				   struct dirent *de)
{
	int err, saved_errno;

	strbuf_addstr(&iter->base.path, de->d_name);
	/*
	 * We have to reset these because the path strbuf might have
	 * been realloc()ed at the previous strbuf_addstr().
	 */
	iter->base.relative_path = iter->base.path.buf +
				   iter->levels[0].prefix_len;
	iter->base.basename = iter->base.path.buf +
			      iter->levels[iter->levels_nr - 1].prefix_len;

	if (iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS)
		err = stat(iter->base.path.buf, &iter->base.st);
	else
		err = lstat(iter->base.path.buf, &iter->base.st);

	saved_errno = errno;
	if (err && errno != ENOENT)
		warning_errno("failed to stat '%s'", iter->base.path.buf);

	errno = saved_errno;
	return err;
}

int dir_iterator_advance(struct dir_iterator *dir_iterator)
{
	struct dir_iterator_int *iter =
		(struct dir_iterator_int *)dir_iterator;

	if (S_ISDIR(iter->base.st.st_mode) && push_level(iter)) {
		if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
			goto error_out;
		if (iter->levels_nr == 0)
			goto error_out;
	}

	/* Loop until we find an entry that we can give back to the caller. */
	while (1) {
		struct dirent *de;
		struct dir_iterator_level *level =
			&iter->levels[iter->levels_nr - 1];

		strbuf_setlen(&iter->base.path, level->prefix_len);
		errno = 0;
		de = readdir(level->dir);

		if (!de) {
			if (errno) {
				warning_errno("error reading directory '%s'",
					      iter->base.path.buf);
				if (iter->flags & DIR_ITERATOR_PEDANTIC)
					goto error_out;
			} else if (pop_level(iter) == 0) {
				return dir_iterator_abort(dir_iterator);
			}
			continue;
		}

		if (is_dot_or_dotdot(de->d_name))
			continue;

		if (prepare_next_entry_data(iter, de)) {
			if (errno != ENOENT && iter->flags & DIR_ITERATOR_PEDANTIC)
				goto error_out;
			continue;
		}

		return ITER_OK;
	}

error_out:
	dir_iterator_abort(dir_iterator);
	return ITER_ERROR;
}

int dir_iterator_abort(struct dir_iterator *dir_iterator)
{
	struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;

	for (; iter->levels_nr; iter->levels_nr--) {
		struct dir_iterator_level *level =
			&iter->levels[iter->levels_nr - 1];

		if (level->dir && closedir(level->dir)) {
			int saved_errno = errno;
			strbuf_setlen(&iter->base.path, level->prefix_len);
			errno = saved_errno;
			warning_errno("error closing directory '%s'",
				      iter->base.path.buf);
		}
	}

	free(iter->levels);
	strbuf_release(&iter->base.path);
	free(iter);
	return ITER_DONE;
}

struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags)
{
	struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
	struct dir_iterator *dir_iterator = &iter->base;
	int saved_errno, err;

	strbuf_init(&iter->base.path, PATH_MAX);
	strbuf_addstr(&iter->base.path, path);

	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
	iter->levels_nr = 0;
	iter->flags = flags;

	/*
	 * Note: stat/lstat already checks for NULL or empty strings and
	 * nonexistent paths.
	 */
	if (iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS)
		err = stat(iter->base.path.buf, &iter->base.st);
	else
		err = lstat(iter->base.path.buf, &iter->base.st);

	if (err < 0) {
		saved_errno = errno;
		goto error_out;
	}

	if (!S_ISDIR(iter->base.st.st_mode)) {
		saved_errno = ENOTDIR;
		goto error_out;
	}

	return dir_iterator;

error_out:
	dir_iterator_abort(dir_iterator);
	errno = saved_errno;
	return NULL;
}