+ SHA1Checksum block_hash;
+ block_hash.process(block_buf, bytes);
+ string block_csum = block_hash.checksum_str();
+
+ if (all_zero) {
+ ref = ObjectReference(ObjectReference::REF_ZERO);
+ ref.set_range(0, bytes);
+ } else {
+ ObjectReference ref = db->FindObject(block_csum, bytes);
+ }
+
+ // Store a copy of the object if one does not yet exist
+ if (ref.is_null()) {
+ LbsObject *o = new LbsObject;
+ int object_group;
+
+ /* We might still have seen this checksum before, if the object
+ * was stored at some time in the past, but we have decided to
+ * clean the segment the object was originally stored in
+ * (FindObject will not return such objects). When rewriting
+ * the object contents, put it in a separate group, so that old
+ * objects get grouped together. The hope is that these old
+ * objects will continue to be used in the future, and we
+ * obtain segments which will continue to be well-utilized.
+ * Additionally, keep track of the age of the data by looking
+ * up the age of the block which was expired and using that
+ * instead of the current time. */
+ if (db->IsOldObject(block_csum, bytes,
+ &block_age, &object_group)) {
+ if (object_group == 0) {
+ o->set_group("data");
+ } else {
+ char group[32];
+ sprintf(group, "compacted-%d", object_group);
+ o->set_group(group);
+ }
+ if (status == NULL)
+ status = "partial";
+ } else {
+ o->set_group("data");
+ status = "new";
+ }
+
+ o->set_data(block_buf, bytes);
+ o->write(tss);
+ ref = o->get_ref();
+ db->StoreObject(ref, block_csum, bytes, block_age);
+ ref.set_range(0, bytes);
+ delete o;
+ }
+
+ object_list.push_back(ref.to_string());
+ if (ref.is_normal())
+ add_segment(ref.get_segment());
+ db->UseObject(ref);
+ size += bytes;
+
+ if (status == NULL)
+ status = "old";