add `seqno` into iterator (#198)

.gitignore

@@ -6,6 +6,9 @@ titandb_bench
 titandb_stress
 
 build/
+rocksdb
+Makefile
+*.cmake
 .idea/
 .vscode/
 cmake-build-debug/

src/compaction_filter.h

@@ -31,15 +31,16 @@ class TitanCompactionFilter final : public CompactionFilter {
 
   const char *Name() const override { return filter_name_.c_str(); }
 
-  Decision FilterV2(int level, const Slice &key, ValueType value_type,
-                    const Slice &value, std::string *new_value,
+  Decision FilterV3(int level, const Slice &key, SequenceNumber seqno,
+                    ValueType value_type, const Slice &value,
+                    std::string *new_value,
                     std::string *skip_until) const override {
     if (skip_value_) {
-      return original_filter_->FilterV2(level, key, value_type, Slice(),
+      return original_filter_->FilterV3(level, key, seqno, value_type, Slice(),
                                         new_value, skip_until);
     }
     if (value_type != kBlobIndex) {
-      return original_filter_->FilterV2(level, key, value_type, value,
+      return original_filter_->FilterV3(level, key, seqno, value_type, value,
                                         new_value, skip_until);
     }
 
@@ -73,8 +74,8 @@ class TitanCompactionFilter final : public CompactionFilter {
       // TODO(yiwu): Tell the two cases apart.
       return Decision::kKeep;
     } else if (s.ok()) {
-      auto decision = original_filter_->FilterV2(
-          level, key, kValue, record.value, new_value, skip_until);
+      auto decision = original_filter_->FilterV3(
+          level, key, seqno, kValue, record.value, new_value, skip_until);
 
       // It would be a problem if it change the value whereas the value_type
       // is still kBlobIndex. For now, just returns kKeep.

src/db_iter.h

@@ -116,6 +116,10 @@ class TitanDBIterator : public Iterator {
     return record_.value;
   }
 
+  bool seqno(SequenceNumber* number) const override {
+    return iter_->seqno(number);
+  }
+
  private:
   bool ShouldGetBlobValue() {
     if (!iter_->Valid() || !iter_->IsBlob() || options_.key_only) {