1 files changed, 57 insertions, 2 deletions

diff --git a/pack-objects.h b/pack-objects.h
index 62806ccc39..2ca39cfcfe 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -103,6 +103,7 @@ struct object_entry {
 	unsigned no_try_delta:1;
 	unsigned type_:TYPE_BITS;
 	unsigned in_pack_type:TYPE_BITS; /* could be delta */
+
 	unsigned preferred_base:1; /*
 				    * we do not pack this, but is available
 				    * to be used as the base object to delta
@@ -112,6 +113,7 @@ struct object_entry {
 	unsigned filled:1; /* assigned write-order */
 	unsigned dfs_state:OE_DFS_STATE_BITS;
 	unsigned depth:OE_DEPTH_BITS;
+	unsigned ext_base:1; /* delta_idx points outside packlist */
 
 	/*
 	 * pahole results on 64-bit linux (gcc and clang)
@@ -147,8 +149,20 @@ struct packing_data {
 	pthread_mutex_t lock;
 #endif
 
+	/*
+	 * This list contains entries for bases which we know the other side
+	 * has (e.g., via reachability bitmaps), but which aren't in our
+	 * "objects" list.
+	 */
+	struct object_entry *ext_bases;
+	uint32_t nr_ext, alloc_ext;
+
 	uintmax_t oe_size_limit;
 	uintmax_t oe_delta_size_limit;
+
+	/* delta islands */
+	unsigned int *tree_depth;
+	unsigned char *layer;
 };
 
 void prepare_packing_data(struct packing_data *pdata);
@@ -249,9 +263,12 @@ static inline struct object_entry *oe_delta(
 		const struct packing_data *pack,
 		const struct object_entry *e)
 {
-	if (e->delta_idx)
+	if (!e->delta_idx)
+		return NULL;
+	if (e->ext_base)
+		return &pack->ext_bases[e->delta_idx - 1];
+	else
 		return &pack->objects[e->delta_idx - 1];
-	return NULL;
 }
 
 static inline void oe_set_delta(struct packing_data *pack,
@@ -264,6 +281,10 @@ static inline void oe_set_delta(struct packing_data *pack,
 		e->delta_idx = 0;
 }
 
+void oe_set_delta_ext(struct packing_data *pack,
+		      struct object_entry *e,
+		      const unsigned char *sha1);
+
 static inline struct object_entry *oe_delta_child(
 		const struct packing_data *pack,
 		const struct object_entry *e)
@@ -384,4 +405,38 @@ static inline void oe_set_delta_size(struct packing_data *pack,
 	}
 }
 
+static inline unsigned int oe_tree_depth(struct packing_data *pack,
+					 struct object_entry *e)
+{
+	if (!pack->tree_depth)
+		return 0;
+	return pack->tree_depth[e - pack->objects];
+}
+
+static inline void oe_set_tree_depth(struct packing_data *pack,
+				     struct object_entry *e,
+				     unsigned int tree_depth)
+{
+	if (!pack->tree_depth)
+		ALLOC_ARRAY(pack->tree_depth, pack->nr_objects);
+	pack->tree_depth[e - pack->objects] = tree_depth;
+}
+
+static inline unsigned char oe_layer(struct packing_data *pack,
+				     struct object_entry *e)
+{
+	if (!pack->layer)
+		return 0;
+	return pack->layer[e - pack->objects];
+}
+
+static inline void oe_set_layer(struct packing_data *pack,
+				struct object_entry *e,
+				unsigned char layer)
+{
+	if (!pack->layer)
+		ALLOC_ARRAY(pack->layer, pack->nr_objects);
+	pack->layer[e - pack->objects] = layer;
+}
+
 #endif