get rid of num_packed_objects()

The coming index format change doesn't allow for the number of objects
to be determined from the size of the index file directly.  Instead, Let's
initialize a field in the packed_git structure with the object count when
the index is validated since the count is always known at that point.

(based on commit 57059091fa)

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-count-objects.c

@@ -110,7 +110,7 @@ int cmd_count_objects(int ac, const char **av, const char *prefix)
 		for (p = packed_git; p; p = p->next) {
 			if (!p->pack_local)
 				continue;
-			packed += num_packed_objects(p);
+			packed += p->num_objects;
 		}
 		printf("count: %lu\n", loose);
 		printf("size: %lu\n", loose_size / 2);

builtin-pack-objects.c

@@ -168,7 +168,7 @@ static int cmp_offset(const void *a_, const void *b_)
 static void prepare_pack_revindex(struct pack_revindex *rix)
 {
 	struct packed_git *p = rix->p;
-	int num_ent = num_packed_objects(p);
+	int num_ent = p->num_objects;
 	int i;
 	const char *index = p->index_data;
 
@@ -202,7 +202,7 @@ static struct revindex_entry * find_packed_object(struct packed_git *p,
 		prepare_pack_revindex(rix);
 	revindex = rix->revindex;
 	lo = 0;
-	hi = num_packed_objects(p) + 1;
+	hi = p->num_objects + 1;
 	do {
 		int mi = (lo + hi) / 2;
 		if (revindex[mi].offset == ofs) {

cache.h

@@ -336,6 +336,7 @@ extern struct packed_git {
 	unsigned long pack_size;
 	const void *index_data;
 	void *pack_base;
+	unsigned int num_objects;
 	int index_version;
 	unsigned int pack_last_used;
 	unsigned int pack_use_cnt;
@@ -387,7 +388,6 @@ extern struct packed_git *find_sha1_pack(const unsigned char *sha1,
 extern int use_packed_git(struct packed_git *);
 extern void unuse_packed_git(struct packed_git *);
 extern struct packed_git *add_packed_git(char *, int, int);
-extern int num_packed_objects(const struct packed_git *p);
 extern const unsigned char *nth_packed_object_sha1(const struct packed_git *, unsigned int);
 extern unsigned long find_pack_entry_one(const unsigned char *, struct packed_git *);
 extern void *unpack_entry_gently(struct packed_git *, unsigned long, char *, unsigned long *);

fsck-objects.c

@@ -550,7 +550,7 @@ int main(int argc, char **argv)
 			verify_pack(p, 0);
 
 		for (p = packed_git; p; p = p->next) {
-			int num = num_packed_objects(p);
+			int num = p->num_objects;
 			for (i = 0; i < num; i++)
 				fsck_sha1(nth_packed_object_sha1(p, i));
 		}

pack-check.c

@@ -22,10 +22,10 @@ static int verify_packfile(struct packed_git *p)
 		return error("Packfile version %d unsupported",
 			     ntohl(hdr->hdr_version));
 	nr_objects = ntohl(hdr->hdr_entries);
-	if (num_packed_objects(p) != nr_objects)
+	if (p->num_objects != nr_objects)
 		return error("Packfile claims to have %d objects, "
 			     "while idx size expects %d", nr_objects,
-			     num_packed_objects(p));
+			     p->num_objects);
 
 	/* Check integrity of pack data with its SHA-1 checksum */
 	SHA1_Init(&ctx);

sha1_file.c

@@ -458,6 +458,7 @@ static int check_packed_git_idx(const char *path,  struct packed_git *p)
 	p->index_version = 1;
 	p->index_data = idx_map;
 	p->index_size = idx_size;
+	p->num_objects = nr;
 	return 0;
 }
 
@@ -1171,18 +1172,12 @@ void *unpack_entry_gently(struct packed_git *p, unsigned long offset,
 	}
 }
 
-int num_packed_objects(const struct packed_git *p)
-{
-	/* See check_packed_git_idx() */
-	return (p->index_size - 20 - 20 - 4*256) / 24;
-}
-
 const unsigned char *nth_packed_object_sha1(const struct packed_git *p,
 					    unsigned int n)
 {
 	const unsigned char *index = p->index_data;
 	index += 4 * 256;
-	if (num_packed_objects(p) <= n)
+	if (n >= p->num_objects)
 		return NULL;
 	return index + 24 * n + 4;
 }

sha1_name.c

@@ -76,7 +76,7 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 
 	prepare_packed_git();
 	for (p = packed_git; p && found < 2; p = p->next) {
-		unsigned num = num_packed_objects(p);
+		unsigned num = p->num_objects;
 		unsigned first = 0, last = num;
 		while (first < last) {
 			unsigned mid = (first + last) / 2;