dir.[ch]: add 'follow_symlink' arg to 'get_dtype'

Add a 'follow_symlink' boolean option to 'get_type()'. If 'follow_symlink'
is enabled, DT_LNK (in addition to DT_UNKNOWN) d_types triggers the
stat-based d_type resolution, using 'stat' instead of 'lstat' to get the
type of the followed symlink. Note that symlinks are not followed
recursively, so a symlink pointing to another symlink will still resolve to
DT_LNK.

Update callers in 'diagnose.c' to specify 'follow_symlink = 0' to preserve
current behavior.

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/dir.h b/dir.h
index 28c630ce80..98aa85fcc0 100644
--- a/dir.h
+++ b/dir.h
@@ -368,11 +368,16 @@ struct dirent *readdir_skip_dot_and_dotdot(DIR *dirp);
  * stat.st_mode using the path to the dirent's containing directory (path) and
  * the name of the dirent itself.
  *
+ * If 'follow_symlink' is 1, this function will attempt to follow DT_LNK types
+ * using 'stat'. Links are *not* followed recursively, so a symlink pointing
+ * to another symlink will still resolve to 'DT_LNK'.
+ *
  * Note that 'path' is assumed to have a trailing slash. It is also modified
  * in-place during the execution of the function, but is then reverted to its
  * original value before returning.
  */
-unsigned char get_dtype(struct dirent *e, struct strbuf *path);
+unsigned char get_dtype(struct dirent *e, struct strbuf *path,
+			int follow_symlink);
 
 /*Count the number of slashes for string s*/
 int count_slashes(const char *s);