pack-revindex: store entries directly in packed_git

A pack_revindex struct has two elements: the revindex
entries themselves, and a pointer to the packed_git. We need
both to do lookups, because only the latter knows things
like the number of objects in the pack.

Now that packed_git contains the pack_revindex struct it's
just as easy to pass around the packed_git itself, and we do
not need the extra back-pointer.

We can instead just store the entries directly in the pack.
All functions which took a pack_revindex now just take a
packed_git. We still lazy-load in find_pack_revindex, so
most callers are unaffected.

The exception is the bitmap code, which computes the
revindex and caches the pointer when we load the bitmaps. We
can continue to load, drop the extra cache pointer, and just
access bitmap_git.pack.revindex directly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 22 insertions, 25 deletions

diff --git a/pack-revindex.c b/pack-revindex.c
index 8e63dbc..155a8a3 100644
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -115,14 +115,13 @@ static void sort_revindex(struct revindex_entry *entries, unsigned n, off_t max)
 /*
  * Ordered list of offsets of objects in the pack.
  */
-static void create_pack_revindex(struct pack_revindex *rix)
+static void create_pack_revindex(struct packed_git *p)
 {
-	struct packed_git *p = rix->p;
 	unsigned num_ent = p->num_objects;
 	unsigned i;
 	const char *index = p->index_data;
 
-	rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
+	p->revindex = xmalloc(sizeof(*p->revindex) * (num_ent + 1));
 	index += 4 * 256;
 
 	if (p->index_version > 1) {
@@ -132,46 +131,42 @@ static void create_pack_revindex(struct pack_revindex *rix)
 		for (i = 0; i < num_ent; i++) {
 			uint32_t off = ntohl(*off_32++);
 			if (!(off & 0x80000000)) {
-				rix->revindex[i].offset = off;
+				p->revindex[i].offset = off;
 			} else {
-				rix->revindex[i].offset =
+				p->revindex[i].offset =
 					((uint64_t)ntohl(*off_64++)) << 32;
-				rix->revindex[i].offset |=
+				p->revindex[i].offset |=
 					ntohl(*off_64++);
 			}
-			rix->revindex[i].nr = i;
+			p->revindex[i].nr = i;
 		}
 	} else {
 		for (i = 0; i < num_ent; i++) {
 			uint32_t hl = *((uint32_t *)(index + 24 * i));
-			rix->revindex[i].offset = ntohl(hl);
-			rix->revindex[i].nr = i;
+			p->revindex[i].offset = ntohl(hl);
+			p->revindex[i].nr = i;
 		}
 	}
 
 	/* This knows the pack format -- the 20-byte trailer
 	 * follows immediately after the last object data.
 	 */
-	rix->revindex[num_ent].offset = p->pack_size - 20;
-	rix->revindex[num_ent].nr = -1;
-	sort_revindex(rix->revindex, num_ent, p->pack_size);
+	p->revindex[num_ent].offset = p->pack_size - 20;
+	p->revindex[num_ent].nr = -1;
+	sort_revindex(p->revindex, num_ent, p->pack_size);
 }
 
-struct pack_revindex *revindex_for_pack(struct packed_git *p)
+void load_pack_revindex(struct packed_git *p)
 {
-	struct pack_revindex *rix = &p->reverse_index;
-	if (!rix->revindex) {
-		rix->p = p;
-		create_pack_revindex(rix);
-	}
-	return rix;
+	if (!p->revindex)
+		create_pack_revindex(p);
 }
 
-int find_revindex_position(struct pack_revindex *pridx, off_t ofs)
+int find_revindex_position(struct packed_git *p, off_t ofs)
 {
 	int lo = 0;
-	int hi = pridx->p->num_objects + 1;
-	struct revindex_entry *revindex = pridx->revindex;
+	int hi = p->num_objects + 1;
+	struct revindex_entry *revindex = p->revindex;
 
 	do {
 		unsigned mi = lo + (hi - lo) / 2;
@@ -189,11 +184,13 @@ int find_revindex_position(struct pack_revindex *pridx, off_t ofs)
 
 struct revindex_entry *find_pack_revindex(struct packed_git *p, off_t ofs)
 {
-	struct pack_revindex *pridx = revindex_for_pack(p);
-	int pos = find_revindex_position(pridx, ofs);
+	int pos;
+
+	load_pack_revindex(p);
+	pos = find_revindex_position(p, ofs);
 
 	if (pos < 0)
 		return NULL;
 
-	return pridx->revindex + pos;
+	return p->revindex + pos;
 }