notes: track whether notes_trees were changed at all

Currently, the notes copying is a bit wasteful since it always creates
new trees, even if no notes were copied at all.

Teach add_note() and remove_note() to flag the affected notes tree as
changed ('dirty').  Then teach builtin/notes.c to use this knowledge
and avoid committing trees that weren't changed.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-notes.c b/builtin-notes.c
index 2e45be9de7ba561f421e82516144ba6f182c5e99..e5046b98ed1bd086457562fd21d494259c765f45 100644 (file)
--- a/builtin-notes.c
+++ b/builtin-notes.c
@@ -249,6 +249,8 @@ int commit_notes(struct notes_tree *t, const char *msg)
                t = &default_notes_tree;
        if (!t->initialized || !t->ref || !*t->ref)
                die("Cannot commit uninitialized/unreferenced notes tree");
+       if (!t->dirty)
+               return 0; /* don't have to commit an unchanged tree */
 
        /* Prepare commit message and reflog message */
        strbuf_addstr(&buf, "notes: "); /* commit message starts at index 7 */

diff --git a/notes.c b/notes.c
index 2feeb7bb06ce5073d6813e447f13f1205e2d87c4..0261e7898a5ed6412f92a614818f75c53253b280 100644 (file)
--- a/notes.c
+++ b/notes.c
@@ -933,6 +933,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
        t->ref = notes_ref ? xstrdup(notes_ref) : NULL;
        t->combine_notes = combine_notes;
        t->initialized = 1;
+       t->dirty = 0;
 
        if (flags & NOTES_INIT_EMPTY || !notes_ref ||
            read_ref(notes_ref, object_sha1))
@@ -1011,6 +1012,7 @@ void add_note(struct notes_tree *t, const unsigned char *object_sha1,
        if (!t)
                t = &default_notes_tree;
        assert(t->initialized);
+       t->dirty = 1;
        if (!combine_notes)
                combine_notes = t->combine_notes;
        l = (struct leaf_node *) xmalloc(sizeof(struct leaf_node));
@@ -1026,6 +1028,7 @@ void remove_note(struct notes_tree *t, const unsigned char *object_sha1)
        if (!t)
                t = &default_notes_tree;
        assert(t->initialized);
+       t->dirty = 1;
        hashcpy(l.key_sha1, object_sha1);
        hashclr(l.val_sha1);
        return note_tree_remove(t, t->root, 0, &l);

diff --git a/notes.h b/notes.h
index b7fafb448b6b8e50878548e1b5f6fa2bfe18e6a2..ee65bd1a2430d4af53f03fd2cc9faa916863408c 100644 (file)
--- a/notes.h
+++ b/notes.h
@@ -40,6 +40,7 @@ extern struct notes_tree {
        char *ref;
        combine_notes_fn *combine_notes;
        int initialized;
+       int dirty;
 } default_notes_tree;
 
 /*