graft awareness

Adds support for graft commits in rev-cache (w/ test), and slightly alters graft mechanism. Before, parse_commit() checked the graft list on every commit. Now register_commit_graft() preemptively loads graft commits into memory, and sets a new 'graft' flag in the object. This allows awareness of the commits' medical history without searching a (normally private) array upon each commit.

---

builtin/rev-cache.c       |   14 ++++++++++++--
commit.c                  |   34 +++++++++++++++++++++++++++++++---
object.h                  |    3 ++-
rev-cache.c               |   32 ++++++++++++++++++++++++++++++++
t/t6019-rev-cache-list.sh |    7 +++++++
5 files changed, 84 insertions(+), 6 deletions(-)

index 59fc833..404e48c 100644
@@ -102,8 +102,18 @@ static int test_rev_list(int argc, const char *argv[])

			flags ^= UNINTERESTING;
		else if (!strcmp(argv[i], "--objects"))
			revs.tree_objects = revs.blob_objects = 1;

- else
- handle_revision_arg(argv[i], &revs, flags, 1);
+ else {
+ struct commit_graft graft;
+
+ if (argv[i][0] == ':') {
+ handle_revision_arg(argv[i] + 1, &revs, flags, 1);
+
+ hashcpy(graft.sha1, revs.pending.objects[revs.pending.nr - 1].item->sha1);
+ graft.nr_parent = -1;
+ register_commit_graft(&graft, 0);
+ } else
+ handle_revision_arg(argv[i], &revs, flags, 1);
+ }

	}

	setup_revisions(0, 0, &revs, 0);

index 263dd74..23f3bb9 100644
@@ -100,6 +100,7 @@ static int commit_graft_pos(const unsigned char *sha1)
 

int register_commit_graft(struct commit_graft *graft, int ignore_dups) {

+	struct commit *commit;
	int pos = commit_graft_pos(graft->sha1);

	if (0 <= pos) {
@@ -124,6 +125,17 @@ int register_commit_graft(struct commit_graft *graft, int ignore_dups)
			(commit_graft_nr - pos - 1) *
			sizeof(*commit_graft));
	commit_graft[pos] = graft;

+
+ commit = lookup_commit(graft->sha1);
+ commit->object.graft = 1;
+ if (commit->object.parsed) {
+ /* we don't want to call this from a parse_commit(), but
+ * we should ensure commit's parents are "correct"
+ */
+ commit->object.parsed = 0;
+ parse_commit(commit);
+ }
+

	return 0;
}

@@ -220,6 +232,7 @@ int write_shallow_commits(struct strbuf *out, int use_pack_protocol)

int unregister_shallow(const unsigned char *sha1)
{

+	struct commit *commit;
	int pos = commit_graft_pos(sha1);
	if (pos < 0)
		return -1;

@@ -228,6 +241,12 @@ int unregister_shallow(const unsigned char *sha1)
sizeof(struct commit_graft *)
* (commit_graft_nr - pos - 1));
commit_graft_nr--;
+
+ commit = lookup_commit(sha1);
+ commit->object.graft = 0;
+ commit->object.parsed = 0;
+ parse_commit(commit);
+

	return 0;
}

@@ -241,7 +260,6 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)

	if (item->object.parsed)
		return 0;
-	item->object.parsed = 1;
	tail += size;
	if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
		return error("bogus commit object %s", sha1_to_hex(item->object.sha1));

@@ -254,7 +272,13 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
while (pop_commit(pptr))
; /* clear anything from cache */

- graft = lookup_commit_graft(item->object.sha1);
+ /* make sure .graft flag is initialized */
+ prepare_commit_graft();
+ if (item->object.graft)
+ graft = lookup_commit_graft(item->object.sha1);
+ else
+ graft = 0;
+

	while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
		struct commit *new_parent;

@@ -282,8 +306,12 @@ int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)

				continue;
			pptr = &commit_list_insert(new_parent, pptr)->next;
		}

- }
+ item->object.graft = 1;
+ } else
+ item->object.graft = 0;
+

	item->date = parse_commit_date(bufptr, tail);

+ item->object.parsed = 1;

	return 0;
}

index 82877c8..8123824 100644
@@ -22,7 +22,7 @@ struct object_array {

};

#define TYPE_BITS   3
-#define FLAG_BITS  27
+#define FLAG_BITS  26

/*
* The object type is stored in 3 bits.
@@ -30,6 +30,7 @@ struct object_array {

struct object {
	unsigned parsed : 1;
	unsigned used : 1;
+	unsigned graft : 1;
	unsigned type : TYPE_BITS;
	unsigned flags : FLAG_BITS;
	unsigned char sha1[20];

index 4f1ea34..dfb3212 100644
@@ -754,9 +754,41 @@ static int traverse_cache_slice_1(struct rc_slice_header *head, unsigned char *m

			}
		} else if (!ipath_nr && co->date <= date)
			slop--;
+		else if (!ipath_nr && !upath_nr)
+			break;
		else
			slop = SLOP;

+ /* before opening further topo-relations, check if the parenting has had medical attention */
+ if (obj->graft) {
+ struct commit_list *list;
+
+ parse_commit(co);
+ obj->flags &= ~FACE_VALUE;
+ last_objects[path] = 0;
+
+ /* we're only interested in its indirect influence */
+ for (list = co->parents; list; list = list->next) {
+ struct rc_index_entry *iep;
+ struct object *po = &list->item->object;
+
+ iep = search_index(po->sha1);
+ if (!iep || hashcmp(idx_caches + 20 * iep->cache_index, head->sha1)) {
+ if (!(obj->flags & UNINTERESTING) && !(po->flags & UNINTERESTING))
+ ioutside = 1;
+ }
+ }
+
+ /* an abrupt end */
+ myworkp = &commit_list_insert(co, myworkp)->next;
+ if (uninteresting)
+ upath_nr--;
+ else
+ ipath_nr--;
+ paths[path] = 0;
+ continue;
+ }
+

		/* open parents */
		if (entry->merge_nr) {
			int j, off = index + OBJECT_ENTRY_SIZE;

index b7eff3f..5664de7 100644
@@ -92,6 +92,7 @@ git rev-list --topo-order HEAD --not HEAD~2 >proper_commit_list_limited2

git rev-list --topo-order HEAD >proper_commit_list
git rev-list --objects HEAD >proper_object_list
git rev-list HEAD --max-age=$min_date --min-age=$max_date >proper_list_date_limited +git rev-cache test HEAD :HEAD~2 >proper_shallow_list 2>/dev/null

cache_sha1=git rev-cache add HEAD 2>output.err

@@ -252,5 +253,11 @@ test_expect_success 'test --ignore-size function in fuse' '
test -e .git/rev-cache/$cache_sha1
'

+#test graft handling
+test_expect_success 'check graft handling' '
+ git rev-cache test HEAD :HEAD~2 >list
+ test_cmp list proper_shallow_list
+'
+
test_done

tg: (68204ac..) t/rc/graft (depends on: t/rc/names)