When an object is garbage collected by Git, any notes that annotate that
object is not automatically garbage-collected, since all notes are trivially
reachable from a notes ref. In order to remove notes for non-existing objects,
we therefore need to add functionality for traversing the notes tree and
explicitly removing references to notes that annotate non-reachable objects.
Thus the notes objects themselves also become unreachable, and are removed
by a later GC.
gc_notes() performs this traversal (by using for_each_note() internally), and
removes the notes in question from the notes tree.
Note that the effect of gc_notes() is not persistent unless a subsequent call
to write_notes_tree() is made.
Signed-off-by: Johan Herland <johan@xxxxxxxxxxx>
---
notes.c | 39 +++++++++++++++++++++++++++++++++++++++
notes.h | 12 ++++++++++++
2 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/notes.c b/notes.c
index 4f260a5..880a306 100644
--- a/notes.c
+++ b/notes.c
@@ -747,6 +747,29 @@ static int write_each_note(const unsigned char *object_sha1,
write_each_note_helper(d->root, note_path, mode, note_sha1);
}
+struct note_delete_list {
+ struct note_delete_list *next;
+ const unsigned char *sha1;
+};
+
+static int gc_notes_helper(const unsigned char *object_sha1,
+ const unsigned char *note_sha1, char *note_path,
+ void *cb_data)
+{
+ struct note_delete_list **l = (struct note_delete_list **) cb_data;
+ struct note_delete_list *n;
+
+ if (has_sha1_file(object_sha1))
+ return 0; /* nothing to do for this note */
+
+ /* failed to find object => GC this note */
+ n = (struct note_delete_list *) xmalloc(sizeof(*n));
+ n->next = *l;
+ n->sha1 = object_sha1;
+ *l = n;
+ return 0;
+}
+
int combine_notes_concatenate(unsigned char *cur_sha1,
const unsigned char *new_sha1)
{
@@ -920,6 +943,22 @@ int write_notes_tree(struct notes_tree *t, unsigned char *result)
return ret;
}
+void gc_notes(struct notes_tree *t)
+{
+ struct note_delete_list *l = NULL;
+
+ if (!t)
+ t = &default_notes_tree;
+ assert(t->initialized);
+
+ for_each_note(t, 0, gc_notes_helper, &l);
+
+ while (l) {
+ remove_note(t, l->sha1);
+ l = l->next;
+ }
+}
+
void free_notes(struct notes_tree *t)
{
if (!t)
diff --git a/notes.h b/notes.h
index f25643e..71d3fab 100644
--- a/notes.h
+++ b/notes.h
@@ -158,6 +158,18 @@ int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
int write_notes_tree(struct notes_tree *t, unsigned char *result);
/*
+ * Remove all notes annotating non-existing objects from the given notes tree
+ *
+ * All notes in the given notes_tree that are associated with objects that no
+ * longer exist in the database, are removed from the notes tree.
+ *
+ * IMPORTANT: The changes made by gc_notes() to the given notes_tree structure
+ * are not persistent until a subsequent call to write_notes_tree() returns
+ * zero.
+ */
+void gc_notes(struct notes_tree *t);
+
+/*
* Free (and de-initialize) the given notes_tree structure
*
* IMPORTANT: Changes made to the given notes_tree since the last, successful
--
1.6.6.rc1.321.g0496e
--
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