dir.[ch]: expose 'get_dtype'

Move 'get_dtype()' from 'diagnose.c' to 'dir.c' and add its declaration to
'dir.h' so that it is accessible to callers in other files. The function and
its documentation are moved verbatim except for a small addition to the
description clarifying what the 'path' arg represents.

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

diagnose.c

@@ -71,42 +71,6 @@ static int dir_file_stats(struct object_directory *object_dir, void *data)
 	return 0;
 }
 
-/*
- * Get the d_type of a dirent. If the d_type is unknown, derive it from
- * stat.st_mode.
- *
- * 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.
- */
-static unsigned char get_dtype(struct dirent *e, struct strbuf *path)
-{
-	struct stat st;
-	unsigned char dtype = DTYPE(e);
-	size_t base_path_len;
-
-	if (dtype != DT_UNKNOWN)
-		return dtype;
-
-	/* d_type unknown in dirent, try to fall back on lstat results */
-	base_path_len = path->len;
-	strbuf_addstr(path, e->d_name);
-	if (lstat(path->buf, &st))
-		goto cleanup;
-
-	/* determine d_type from st_mode */
-	if (S_ISREG(st.st_mode))
-		dtype = DT_REG;
-	else if (S_ISDIR(st.st_mode))
-		dtype = DT_DIR;
-	else if (S_ISLNK(st.st_mode))
-		dtype = DT_LNK;
-
-cleanup:
-	strbuf_setlen(path, base_path_len);
-	return dtype;
-}
-
 static int count_files(struct strbuf *path)
 {
 	DIR *dir = opendir(path->buf);

dir.c

@@ -2235,6 +2235,34 @@ static int get_index_dtype(struct index_state *istate,
 	return DT_UNKNOWN;
 }
 
+unsigned char get_dtype(struct dirent *e, struct strbuf *path)
+{
+	struct stat st;
+	unsigned char dtype = DTYPE(e);
+	size_t base_path_len;
+
+	if (dtype != DT_UNKNOWN)
+		return dtype;
+
+	/* d_type unknown in dirent, try to fall back on lstat results */
+	base_path_len = path->len;
+	strbuf_addstr(path, e->d_name);
+	if (lstat(path->buf, &st))
+		goto cleanup;
+
+	/* determine d_type from st_mode */
+	if (S_ISREG(st.st_mode))
+		dtype = DT_REG;
+	else if (S_ISDIR(st.st_mode))
+		dtype = DT_DIR;
+	else if (S_ISLNK(st.st_mode))
+		dtype = DT_LNK;
+
+cleanup:
+	strbuf_setlen(path, base_path_len);
+	return dtype;
+}
+
 static int resolve_dtype(int dtype, struct index_state *istate,
 			 const char *path, int len)
 {

dir.h

@@ -363,6 +363,17 @@ struct dir_struct {
 
 struct dirent *readdir_skip_dot_and_dotdot(DIR *dirp);
 
+/*
+ * Get the d_type of a dirent. If the d_type is unknown, derive it from
+ * stat.st_mode using the path to the dirent's containing directory (path) and
+ * the name of the dirent itself.
+ *
+ * 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);
+
 /*Count the number of slashes for string s*/
 int count_slashes(const char *s);