dir: add generic "walk all files" helper

There is sometimes a need to visit every file within a directory,
recursively. The main example is remove_dir_recursively(), though it has
some extra flags that make it want to iterate over paths in a custom
way. There is also the fill_directory() approach but that involves an
index and a pathspec.

This change adds a new for_each_file_in_dir() method that will be
helpful in the next change.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/dir.c b/dir.c
index dfb4d40103..7731f7b9d3 100644
--- a/dir.c
+++ b/dir.c
@@ -30,6 +30,7 @@
 #include "read-cache-ll.h"
 #include "setup.h"
 #include "sparse-index.h"
+#include "strbuf.h"
 #include "submodule-config.h"
 #include "symlinks.h"
 #include "trace2.h"
@@ -87,6 +88,33 @@ struct dirent *readdir_skip_dot_and_dotdot(DIR *dirp)
 	return e;
 }
 
+int for_each_file_in_dir(struct strbuf *path, file_iterator fn, const void *data)
+{
+	struct dirent *e;
+	int res = 0;
+	size_t baselen = path->len;
+	DIR *dir = opendir(path->buf);
+
+	if (!dir)
+		return 0;
+
+	while (!res && (e = readdir_skip_dot_and_dotdot(dir)) != NULL) {
+		unsigned char dtype = get_dtype(e, path, 0);
+		strbuf_setlen(path, baselen);
+		strbuf_addstr(path, e->d_name);
+
+		if (dtype == DT_REG) {
+			res = fn(path->buf, data);
+		} else if (dtype == DT_DIR) {
+			strbuf_addch(path, '/');
+			res = for_each_file_in_dir(path, fn, data);
+		}
+	}
+
+	closedir(dir);
+	return res;
+}
+
 int count_slashes(const char *s)
 {
 	int cnt = 0;