+ // Sparse file processing: if we read a block of all zeroes, encode
+ // that explicitly.
+ bool all_zero = true;
+ for (int i = 0; i < bytes; i++) {
+ if (block_buf[i] != 0) {
+ all_zero = false;
+ break;
+ }
+ }
+
+ // Either find a copy of this block in an already-existing segment,
+ // or index it so it can be re-used in the future
+ double block_age = 0.0;
+ ObjectReference ref;
+
+ 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 {
+ ref = db->FindObject(block_csum, bytes);
+ }
+
+ list<ObjectReference> refs;
+
+ // 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";
+ }
+
+ subfile.analyze_new_block(block_buf, bytes);
+ refs = subfile.create_incremental(tss, o, block_age);
+ } else {
+ if (flag_rebuild_statcache && ref.is_normal()) {
+ subfile.analyze_new_block(block_buf, bytes);
+ subfile.store_analyzed_signatures(ref);
+ }
+ refs.push_back(ref);
+ }