Re: [PATCH 7/6 (v4)] support for commit grafts, slight change to general mechanism

[Nick Edelen <sirnot@gmail.com>]

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.

Signed-off-by: Nick Edelen <sirnot@gmail.com>

---
fixed bug in mechanism alteration, which was causing test t6001 to fail.

 builtin-rev-cache.c       |   14 ++++++++++++--
 commit.c                  |   27 +++++++++++++++++++++++++--
 object.h                  |    3 ++-
 rev-cache.c               |   32 ++++++++++++++++++++++++++++++++
 t/t6017-rev-cache-list.sh |    6 ++++++
 5 files changed, 77 insertions(+), 5 deletions(-)

diff --git a/builtin-rev-cache.c b/builtin-rev-cache.c
index 4c1766d..b36bc39 100644
--- a/builtin-rev-cache.c
+++ b/builtin-rev-cache.c
@@ -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);
diff --git a/commit.c b/commit.c
index 61d83c6..c227748 100644
--- a/commit.c
+++ b/commit.c
@@ -99,6 +99,7 @@ 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) {
@@ -123,6 +124,12 @@ 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;
+	commit->object.parsed = 0;
+	parse_commit(commit); /* in case commit was already parsed */
+
 	return 0;
 }
 
@@ -221,6 +228,7 @@ int write_shallow_commits(int fd, 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;
@@ -229,6 +237,12 @@ 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;
 }
 
@@ -255,7 +269,13 @@ 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;
 
@@ -283,7 +303,10 @@ 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);
 
 	return 0;
diff --git a/object.h b/object.h
index 89dd0c4..f848e0f 100644
--- a/object.h
+++ b/object.h
@@ -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];
diff --git a/rev-cache.c b/rev-cache.c
index 6c96297..f7b1cd2 100644
--- a/rev-cache.c
+++ b/rev-cache.c
@@ -664,9 +664,41 @@ 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 (entry->uninteresting)
+				upath_nr--;
+			else
+				ipath_nr--;
+			paths[path] = 0;
+			continue;
+		}
+
 		/* open parents */
 		if (entry->merge_nr) {
 			int j, off = index + sizeof(struct rc_object_entry_ondisk);
diff --git a/t/t6017-rev-cache-list.sh b/t/t6017-rev-cache-list.sh
index f0f3bcf..3e16949 100755
--- a/t/t6017-rev-cache-list.sh
+++ b/t/t6017-rev-cache-list.sh
@@ -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`
 
@@ -252,4 +253,9 @@ test_expect_success 'test --ignore-size function in fuse' '
 	test -e .git/rev-cache/$cache_sha1
 '
 
+test_expect_success 'check graft handling' '
+	git-rev-cache test HEAD :HEAD~2 >list
+	test_cmp list proper_shallow_list
+'
+
 test_done
-- 
tg: (52c9694..) t/revcache/graft (depends on: t/revcache/names)