git/dir-iterator.c
Michael Haggerty 0fe5043dad dir_iterator: new API for iterating over a directory tree
The iterator interface is modeled on that for references, though no
vtable is necessary because there is (so far?) only one type of
dir_iterator.

There are obviously a lot of features that could easily be added to this
class:

* Skip/include directory paths in the iteration
* Shallow/deep iteration
* Letting the caller decide which subdirectories to recurse into (e.g.,
  via a dir_iterator_advance_into() function)
* Option to iterate in sorted order
* Option to iterate over directory paths before vs. after their contents

But these are not needed for the current patch series, so I refrain.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-20 11:38:21 -07:00

203 lines
4.8 KiB
C

#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;
}