From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 16 Oct 2018 07:16:00 +0000 (+0900)
Subject: Merge branch 'jk/delta-islands-with-bitmap-reuse-delta-fix'
X-Git-Tag: v2.20.0-rc0~190
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/73b9c6f58358c2d6167f7a51ac06eee2fab6f5d8?ds=inline;hp=-c

Merge branch 'jk/delta-islands-with-bitmap-reuse-delta-fix'

Fix interactions between two recent topics.

* jk/delta-islands-with-bitmap-reuse-delta-fix:
pack-objects: handle island check for "external" delta base
---

73b9c6f58358c2d6167f7a51ac06eee2fab6f5d8
diff --combined builtin/pack-objects.c
index e6316d294d,fb97bc5ae1..c6370f2716
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@@ -970,7 -970,8 +970,7 @@@ static int no_try_delta(const char *pat
  
  	if (!check)
  		check = attr_check_initl("delta", NULL);
 -	if (git_check_attr(&the_index, path, check))
 -		return 0;
 +	git_check_attr(&the_index, path, check);
  	if (ATTR_FALSE(check->items[0].value))
  		return 1;
  	return 0;
@@@ -1247,7 -1248,7 +1247,7 @@@ static struct pbase_tree_cache *pbase_t
  	 */
  	for (neigh = 0; neigh < 8; neigh++) {
  		ent = pbase_tree_cache[my_ix];
 -		if (ent && !oidcmp(&ent->oid, oid)) {
 +		if (ent && oideq(&ent->oid, oid)) {
  			ent->ref++;
  			return ent;
  		}
@@@ -1429,7 -1430,7 +1429,7 @@@ static void add_preferred_base(struct o
  		return;
  
  	for (it = pbase_tree; it; it = it->next) {
 -		if (!oidcmp(&it->pcache.oid, &tree_oid)) {
 +		if (oideq(&it->pcache.oid, &tree_oid)) {
  			free(data);
  			return;
  		}
@@@ -1469,6 -1470,57 +1469,57 @@@ static void cleanup_preferred_base(void
  	done_pbase_paths_num = done_pbase_paths_alloc = 0;
  }
  
+ /*
+  * Return 1 iff the object specified by "delta" can be sent
+  * literally as a delta against the base in "base_sha1". If
+  * so, then *base_out will point to the entry in our packing
+  * list, or NULL if we must use the external-base list.
+  *
+  * Depth value does not matter - find_deltas() will
+  * never consider reused delta as the base object to
+  * deltify other objects against, in order to avoid
+  * circular deltas.
+  */
+ static int can_reuse_delta(const unsigned char *base_sha1,
+ 			   struct object_entry *delta,
+ 			   struct object_entry **base_out)
+ {
+ 	struct object_entry *base;
+ 
+ 	if (!base_sha1)
+ 		return 0;
+ 
+ 	/*
+ 	 * First see if we're already sending the base (or it's explicitly in
+ 	 * our "excluded" list).
+ 	 */
+ 	base = packlist_find(&to_pack, base_sha1, NULL);
+ 	if (base) {
+ 		if (!in_same_island(&delta->idx.oid, &base->idx.oid))
+ 			return 0;
+ 		*base_out = base;
+ 		return 1;
+ 	}
+ 
+ 	/*
+ 	 * Otherwise, reachability bitmaps may tell us if the receiver has it,
+ 	 * even if it was buried too deep in history to make it into the
+ 	 * packing list.
+ 	 */
+ 	if (thin && bitmap_has_sha1_in_uninteresting(bitmap_git, base_sha1)) {
+ 		if (use_delta_islands) {
+ 			struct object_id base_oid;
+ 			hashcpy(base_oid.hash, base_sha1);
+ 			if (!in_same_island(&delta->idx.oid, &base_oid))
+ 				return 0;
+ 		}
+ 		*base_out = NULL;
+ 		return 1;
+ 	}
+ 
+ 	return 0;
+ }
+ 
  static void check_object(struct object_entry *entry)
  {
  	unsigned long canonical_size;
@@@ -1555,22 -1607,7 +1606,7 @@@
  			break;
  		}
  
- 		if (base_ref && (
- 		    (base_entry = packlist_find(&to_pack, base_ref, NULL)) ||
- 		    (thin &&
- 		     bitmap_has_sha1_in_uninteresting(bitmap_git, base_ref))) &&
- 		    in_same_island(&entry->idx.oid, &base_entry->idx.oid)) {
- 			/*
- 			 * If base_ref was set above that means we wish to
- 			 * reuse delta data, and either we found that object in
- 			 * the list of objects we want to pack, or it's one we
- 			 * know the receiver has.
- 			 *
- 			 * Depth value does not matter - find_deltas() will
- 			 * never consider reused delta as the base object to
- 			 * deltify other objects against, in order to avoid
- 			 * circular deltas.
- 			 */
+ 		if (can_reuse_delta(base_ref, entry, &base_entry)) {
  			oe_set_type(entry, entry->in_pack_type);
  			SET_SIZE(entry, in_pack_size); /* delta size */
  			SET_DELTA_SIZE(entry, in_pack_size);