Add a generic "object decorator" interface, and make object refs use it

This allows you to add an arbitrary "decoration" of your choice to any
object.  It's a space- and time-efficient way to add information to
arbitrary objects, especially if most objects probably do not have the
decoration.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 7 insertions, 62 deletions

diff --git a/object-refs.c b/object-refs.c
index 98ea10005a..022e8d841c 100644
--- a/object-refs.c
+++ b/object-refs.c
@@ -1,75 +1,20 @@
 #include "cache.h"
 #include "object.h"
+#include "decorate.h"
 
 int track_object_refs = 0;
 
-static unsigned int refs_hash_size, nr_object_refs;
-static struct object_refs **refs_hash;
+static struct decoration ref_decorate;
 
-static unsigned int hash_obj(struct object *obj, unsigned int n)
+struct object_refs *lookup_object_refs(struct object *base)
 {
-	unsigned int hash = *(unsigned int *)obj->sha1;
-	return hash % n;
+	return lookup_decoration(&ref_decorate, base);
 }
 
-static void insert_ref_hash(struct object_refs *ref, struct object_refs **hash, unsigned int size)
+static void add_object_refs(struct object *obj, struct object_refs *refs)
 {
-	int j = hash_obj(ref->base, size);
-
-	while (hash[j]) {
-		j++;
-		if (j >= size)
-			j = 0;
-	}
-	hash[j] = ref;
-}
-
-static void grow_refs_hash(void)
-{
-	int i;
-	int new_hash_size = (refs_hash_size + 1000) * 3 / 2;
-	struct object_refs **new_hash;
-
-	new_hash = xcalloc(new_hash_size, sizeof(struct object_refs *));
-	for (i = 0; i < refs_hash_size; i++) {
-		struct object_refs *ref = refs_hash[i];
-		if (!ref)
-			continue;
-		insert_ref_hash(ref, new_hash, new_hash_size);
-	}
-	free(refs_hash);
-	refs_hash = new_hash;
-	refs_hash_size = new_hash_size;
-}
-
-static void add_object_refs(struct object *obj, struct object_refs *ref)
-{
-	int nr = nr_object_refs + 1;
-
-	if (nr > refs_hash_size * 2 / 3)
-		grow_refs_hash();
-	ref->base = obj;
-	insert_ref_hash(ref, refs_hash, refs_hash_size);
-	nr_object_refs = nr;
-}
-
-struct object_refs *lookup_object_refs(struct object *obj)
-{
-	struct object_refs *ref;
-	int j;
-
-	/* nothing to lookup */
-	if (!refs_hash_size)
-		return NULL;
-	j = hash_obj(obj, refs_hash_size);
-	while ((ref = refs_hash[j]) != NULL) {
-		if (ref->base == obj)
-			break;
-		j++;
-		if (j >= refs_hash_size)
-			j = 0;
-	}
-	return ref;
+	if (add_decoration(&ref_decorate, obj, refs))
+		die("object %s tried to add refs twice!", sha1_to_hex(obj->sha1));
 }
 
 struct object_refs *alloc_object_refs(unsigned count)