aboutsummaryrefslogtreecommitdiff
path: root/dir-iterator.c
blob: 34182a9a1c10244126e03a2b117bd8bc75bd9871 (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
#include "cache.h"
#include "dir.h"
#include "iterator.h"
#include "dir-iterator.h"

struct dir_iterator_level {
	int initialized;

	DIR *dir;

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

	/*
	 * The last action that has been taken with the current entry
	 * (needed for directories, which have to be included in the
	 * iteration and also iterated into):
	 */
	enum {
		DIR_STATE_ITER,
		DIR_STATE_RECURSE
	} dir_state;
};

/*
 * 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. This is always
	 * at least 1, because when it becomes 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;
};

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

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

		if (!level->initialized) {
			/*
			 * Note: dir_iterator_begin() ensures that
			 * path is not the empty string.
			 */
			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 && errno != ENOENT) {
				warning("error opening directory %s: %s",
					iter->base.path.buf, strerror(errno));
				/* Popping the level is handled below */
			}

			level->initialized = 1;
		} else if (S_ISDIR(iter->base.st.st_mode)) {
			if (level->dir_state == DIR_STATE_ITER) {
				/*
				 * The directory was just iterated
				 * over; now prepare to iterate into
				 * it.
				 */
				level->dir_state = DIR_STATE_RECURSE;
				ALLOC_GROW(iter->levels, iter->levels_nr + 1,
					   iter->levels_alloc);
				level = &iter->levels[iter->levels_nr++];
				level->initialized = 0;
				continue;
			} else {
				/*
				 * The directory has already been
				 * iterated over and iterated into;
				 * we're done with it.
				 */
			}
		}

		if (!level->dir) {
			/*
			 * This level is exhausted (or wasn't opened
			 * successfully); pop up a level.
			 */
			if (--iter->levels_nr == 0)
				return dir_iterator_abort(dir_iterator);

			continue;
		}

		/*
		 * Loop until we find an entry that we can give back
		 * to the caller:
		 */
		while (1) {
			strbuf_setlen(&iter->base.path, level->prefix_len);
			errno = 0;
			de = readdir(level->dir);

			if (!de) {
				/* This level is exhausted; pop up a level. */
				if (errno) {
					warning("error reading directory %s: %s",
						iter->base.path.buf, strerror(errno));
				} else if (closedir(level->dir))
					warning("error closing directory %s: %s",
						iter->base.path.buf, strerror(errno));

				level->dir = NULL;
				if (--iter->levels_nr == 0)
					return dir_iterator_abort(dir_iterator);
				break;
			}

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

			strbuf_addstr(&iter->base.path, de->d_name);
			if (lstat(iter->base.path.buf, &iter->base.st) < 0) {
				if (errno != ENOENT)
					warning("error reading path '%s': %s",
						iter->base.path.buf,
						strerror(errno));
				continue;
			}

			/*
			 * We have to set these each time because
			 * the path strbuf might have been realloc()ed.
			 */
			iter->base.relative_path =
				iter->base.path.buf + iter->levels[0].prefix_len;
			iter->base.basename =
				iter->base.path.buf + level->prefix_len;
			level->dir_state = DIR_STATE_ITER;

			return ITER_OK;
		}
	}
}

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)) {
			strbuf_setlen(&iter->base.path, level->prefix_len);
			warning("error closing directory %s: %s",
				iter->base.path.buf, strerror(errno));
		}
	}

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

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

	if (!path || !*path)
		die("BUG: empty path passed to dir_iterator_begin()");

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

	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);

	iter->levels_nr = 1;
	iter->levels[0].initialized = 0;

	return dir_iterator;
}