[PATCH v2] [GSoC] remove_subtree(): reimplement using iterators

[Daniel Ferreira <bnmvco@gmail.com>]

Use dir_iterator to traverse through remove_subtree()'s directory tree,
avoiding the need for recursive calls to readdir(). Simplify
remove_subtree()'s code.

A conversion similar in purpose was previously done at 46d092a
("for_each_reflog(): reimplement using iterators", 2016-05-21).

Signed-off-by: Daniel Ferreira <bnmvco@gmail.com>
---

This is a second-version patch of the Google Summer of Code microproject for
refactoring recursive readdir() calls to use dir_iterator instead. v1 can be
found in:

https://public-inbox.org/git/CAGZ79kZwT-9mHTiOJ5CEjk2wDFkn6+NcogjX0=vjhsAh16ANYg@mail.gmail.com/T/#mae023e7a7d7626f00e0923833c4359f5af493730

Additionally, for debugging purposes I turned remove_subtree() into a no-op
and ran git tests. Some failures were at:

* t2000-checkout-cache-clash.sh
* t2003-checkout-cache-mkdir.sh

If you guys could check those files out and warn me if any additional tests
would be welcome, please let me know.

Thanks.

 entry.c | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/entry.c b/entry.c
index c6eea240b..3cb92592d 100644
--- a/entry.c
+++ b/entry.c
@@ -2,6 +2,8 @@
 #include "blob.h"
 #include "dir.h"
 #include "streaming.h"
+#include "iterator.h"
+#include "dir-iterator.h"

 static void create_directories(const char *path, int path_len,
 			       const struct checkout *state)
@@ -46,29 +48,13 @@ static void create_directories(const char *path, int path_len,

 static void remove_subtree(struct strbuf *path)
 {
-	DIR *dir = opendir(path->buf);
-	struct dirent *de;
-	int origlen = path->len;
-
-	if (!dir)
-		die_errno("cannot opendir '%s'", path->buf);
-	while ((de = readdir(dir)) != NULL) {
-		struct stat st;
-
-		if (is_dot_or_dotdot(de->d_name))
-			continue;
-
-		strbuf_addch(path, '/');
-		strbuf_addstr(path, de->d_name);
-		if (lstat(path->buf, &st))
-			die_errno("cannot lstat '%s'", path->buf);
-		if (S_ISDIR(st.st_mode))
-			remove_subtree(path);
-		else if (unlink(path->buf))
+	struct dir_iterator *diter = dir_iterator_begin(path->buf);
+
+	while (dir_iterator_advance(diter) == ITER_OK) {
+		if (unlink(diter->path.buf))
 			die_errno("cannot unlink '%s'", path->buf);
-		strbuf_setlen(path, origlen);
 	}
-	closedir(dir);
+
 	if (rmdir(path->buf))
 		die_errno("cannot rmdir '%s'", path->buf);
 }
--
2.12.1.433.g82305b74f.dirty