[PATCH 11/12] dir.c: provide free_directory() for reclaiming dir_struct memory

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

From: Adam Spiers <git@adamspiers.org>

Signed-off-by: Adam Spiers <git@adamspiers.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/technical/api-directory-listing.txt |  2 ++
 dir.c                                             | 28 +++++++++++++++++++++--
 dir.h                                             |  1 +
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt
index add6f43..ca571a8 100644
--- a/Documentation/technical/api-directory-listing.txt
+++ b/Documentation/technical/api-directory-listing.txt
@@ -76,4 +76,6 @@ marked. If you to exclude files, make sure you have loaded index first.
 
 * Use `dir.entries[]`.
 
+* Call `free_directory()` when none of the contained elements are no longer in use.
+
 (JC)
diff --git a/dir.c b/dir.c
index 81a5dd5..d50634d 100644
--- a/dir.c
+++ b/dir.c
@@ -481,6 +481,16 @@ void add_excludes_from_file(struct dir_struct *dir, const char *fname)
 		die("cannot use %s as an exclude file", fname);
 }
 
+static void free_exclude_stack(struct exclude_stack *stk)
+{
+	free(stk->filebuf);
+	free(stk);
+}
+
+/*
+ * Loads the per-directory exclude list for the substring of base
+ * which has a char length of baselen.
+ */
 static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 {
 	struct exclude_list *el;
@@ -502,8 +512,7 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
 			struct exclude *exclude = el->excludes[--el->nr];
 			free(exclude);
 		}
-		free(stk->filebuf);
-		free(stk);
+		free_exclude_stack(stk);
 	}
 
 	/* Read from the parent directories and push them down. */
@@ -1521,3 +1530,18 @@ void free_pathspec(struct pathspec *pathspec)
 	free(pathspec->items);
 	pathspec->items = NULL;
 }
+
+void free_directory(struct dir_struct *dir)
+{
+	struct exclude_stack *stk;
+	int st;
+	for (st = EXC_CMDL; st <= EXC_FILE; st++)
+		free_excludes(&dir->exclude_list[st]);
+
+	stk = dir->exclude_stack;
+	while (stk) {
+		struct exclude_stack *prev = stk->prev;
+		free_exclude_stack(stk);
+		stk = prev;
+	}
+}
diff --git a/dir.h b/dir.h
index 3921aa9..fb57c66 100644
--- a/dir.h
+++ b/dir.h
@@ -117,6 +117,7 @@ extern void parse_exclude_pattern(const char **string, int *patternlen, int *fla
 extern void add_exclude(const char *string, const char *base,
 			int baselen, struct exclude_list *el, const char *src, int srcpos);
 extern void free_excludes(struct exclude_list *el);
+extern void free_directory(struct dir_struct *dir);
 extern int file_exists(const char *);
 
 extern int is_inside_dir(const char *dir);
-- 
1.8.0.rc0.29.g1fdd78f