dir_iterator_advance() is a large function with two nested loops. Let's
improve its readability factoring out three functions and simplifying
its mechanics. The refactored model will no longer depend on
level.initialized and level.dir_state to keep track of the iteration
state and will perform on a single loop.
Also, dir_iterator_begin() currently does not check if the given string
represents a valid directory path. Since the refactored model will have
to stat() the given path at initialization, let's also check for this
kind of error and make dir_iterator_begin() return NULL, on failures,
with errno appropriately set. And add tests for this new behavior.
Improve documentation at dir-iteration.h and code comments at
dir-iterator.c to reflect the changes and eliminate possible
ambiguities.
Finally, adjust refs/files-backend.c to check for now possible
dir_iterator_begin() failures.
Original-patch-by: Daniel Ferreira <bnmvco@xxxxxxxxx>
Signed-off-by: Matheus Tavares <matheus.bernardino@xxxxxx>
---
When dir_iterator_begin() fails at refs/files-backend.c, I used the same
idea Daniel proposed, which is to initialize an empty iterator with
empty_ref_iterator_begin(). Still, I'm not sure wether we shouldn't
abort execution there instead of returning an empty iterator.
dir_iterator_begin() will fail if the give argument is an empty string,
NULL, an invalid path, a non directory path or on some other stat()
errors. Maybe, on these kind of errors, we don't want the users
of refs/files-backend.c, and therefore should call die() right there?
(Also, NULL and empty string arguments were considered a bug in the
previous version of dir_iterator_begin)
dir-iterator.c | 234 ++++++++++++++++++-----------------
dir-iterator.h | 15 ++-
refs/files-backend.c | 17 ++-
t/helper/test-dir-iterator.c | 5 +
t/t0066-dir-iterator.sh | 13 ++
5 files changed, 163 insertions(+), 121 deletions(-)
diff --git a/dir-iterator.c b/dir-iterator.c
index 0c8880868a..594fe4d67b 100644
--- a/dir-iterator.c
+++ b/dir-iterator.c
@@ -4,8 +4,6 @@
#include "dir-iterator.h"
struct dir_iterator_level {
- int initialized;
-
DIR *dir;
/*
@@ -13,16 +11,6 @@ struct dir_iterator_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;
};
/*
@@ -34,9 +22,11 @@ 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.
+ * 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;
@@ -50,113 +40,118 @@ struct dir_iterator_int {
struct dir_iterator_level *levels;
};
+/*
+ * 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, 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) {
+ if (errno != ENOENT) {
+ warning_errno("error opening directory '%s'",
+ iter->base.path.buf);
+ }
+ iter->levels_nr--;
+ 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.
+ */
+static int prepare_next_entry_data(struct dir_iterator_int *iter,
+ struct dirent *de)
+{
+ 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 (lstat(iter->base.path.buf, &iter->base.st)) {
+ if (errno != ENOENT)
+ warning_errno("failed to stat '%s'", iter->base.path.buf);
+ return -1;
+ }
+
+ return 0;
+}
+
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)) {
+ if (push_level(iter) && iter->levels_nr == 0) {
+ /* Pushing the first level failed */
+ return dir_iterator_abort(dir_iterator);
+ }
+ }
+
+ /* 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];
- 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_errno("error opening directory '%s'",
+ 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);
- /* 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.
- */
- }
+ else if (pop_level(iter) == 0)
+ return dir_iterator_abort(dir_iterator);
+ continue;
}
- 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);
+ if (is_dot_or_dotdot(de->d_name))
+ continue;
+ if (prepare_next_entry_data(iter, de))
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_errno("error reading directory '%s'",
- iter->base.path.buf);
- } else if (closedir(level->dir))
- warning_errno("error closing directory '%s'",
- iter->base.path.buf);
-
- 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_errno("failed to stat '%s'",
- iter->base.path.buf);
- 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;
- }
+ return ITER_OK;
}
}
@@ -187,17 +182,32 @@ 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)
- BUG("empty path passed to dir_iterator_begin()");
+ int saved_errno;
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->levels_nr = 1;
- iter->levels[0].initialized = 0;
+ /*
+ * Note: stat already checks for NULL or empty strings and
+ * inexistent paths.
+ */
+ if (stat(iter->base.path.buf, &iter->base.st) < 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;
}
diff --git a/dir-iterator.h b/dir-iterator.h
index 970793d07a..0822821e56 100644
--- a/dir-iterator.h
+++ b/dir-iterator.h
@@ -8,19 +8,23 @@
*
* Iterate over a directory tree, recursively, including paths of all
* types and hidden paths. Skip "." and ".." entries and don't follow
- * symlinks except for the original path.
+ * symlinks except for the original path. Note that the original path
+ * is not included in the iteration.
*
* Every time dir_iterator_advance() is called, update the members of
* the dir_iterator structure to reflect the next path in the
* iteration. The order that paths are iterated over within a
- * directory is undefined, but directory paths are always iterated
- * over before the subdirectory contents.
+ * directory is undefined, directory paths are always given before
+ * their contents.
*
* A typical iteration looks like this:
*
* int ok;
* struct iterator *iter = dir_iterator_begin(path);
*
+ * if (!iter)
+ * goto error_handler;
+ *
* while ((ok = dir_iterator_advance(iter)) == ITER_OK) {
* if (want_to_stop_iteration()) {
* ok = dir_iterator_abort(iter);
@@ -59,8 +63,9 @@ struct dir_iterator {
};
/*
- * Start a directory iteration over path. Return a dir_iterator that
- * holds the internal state of the iteration.
+ * Start a directory iteration over path. On success, return a
+ * dir_iterator that holds the internal state of the iteration.
+ * In case of failure, return NULL and set errno accordingly.
*
* The iteration includes all paths under path, not including path
* itself and not including "." or ".." entries.
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 63e55e6773..97a54532e3 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2143,13 +2143,22 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = {
static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
const char *gitdir)
{
- struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
- struct ref_iterator *ref_iterator = &iter->base;
+ struct dir_iterator *diter;
+ struct files_reflog_iterator *iter;
+ struct ref_iterator *ref_iterator;
struct strbuf sb = STRBUF_INIT;
- base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
strbuf_addf(&sb, "%s/logs", gitdir);
- iter->dir_iterator = dir_iterator_begin(sb.buf);
+
+ diter = dir_iterator_begin(sb.buf);
+ if (!diter)
+ return empty_ref_iterator_begin();
+
+ iter = xcalloc(1, sizeof(*iter));
+ ref_iterator = &iter->base;
+
+ base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
+ iter->dir_iterator = diter;
iter->ref_store = ref_store;
strbuf_release(&sb);
diff --git a/t/helper/test-dir-iterator.c b/t/helper/test-dir-iterator.c
index 84f50bed8c..fab1ff6237 100644
--- a/t/helper/test-dir-iterator.c
+++ b/t/helper/test-dir-iterator.c
@@ -17,6 +17,11 @@ int cmd__dir_iterator(int argc, const char **argv)
diter = dir_iterator_begin(path.buf);
+ if (!diter) {
+ printf("dir_iterator_begin failure: %d\n", errno);
+ exit(EXIT_FAILURE);
+ }
+
while (dir_iterator_advance(diter) == ITER_OK) {
if (S_ISDIR(diter->st.st_mode))
printf("[d] ");
diff --git a/t/t0066-dir-iterator.sh b/t/t0066-dir-iterator.sh
index 6e06dc038d..c739ed7911 100755
--- a/t/t0066-dir-iterator.sh
+++ b/t/t0066-dir-iterator.sh
@@ -52,4 +52,17 @@ test_expect_success 'dir-iterator should list files in the correct order' '
test_cmp expected-pre-order-output actual-pre-order-output
'
+test_expect_success 'begin should fail upon inexistent paths' '
+ test_must_fail test-tool dir-iterator ./inexistent-path \
+ >actual-inexistent-path-output &&
+ echo "dir_iterator_begin failure: 2" >expected-inexistent-path-output &&
+ test_cmp expected-inexistent-path-output actual-inexistent-path-output
+'
+
+test_expect_success 'begin should fail upon non directory paths' '
+ test_must_fail test-tool dir-iterator ./dir/b >actual-non-dir-output &&
+ echo "dir_iterator_begin failure: 20" >expected-non-dir-output &&
+ test_cmp expected-non-dir-output actual-non-dir-output
+'
+
test_done
--
2.20.1
