1 files changed, 106 insertions, 0 deletions
diff --git a/src/rocksdb/db/arena_wrapped_db_iter.cc b/src/rocksdb/db/arena_wrapped_db_iter.cc
new file mode 100644
index 000000000..f43282a75
--- /dev/null
+++ b/src/rocksdb/db/arena_wrapped_db_iter.cc
@@ -0,0 +1,106 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/arena_wrapped_db_iter.h"
+#include "memory/arena.h"
+#include "rocksdb/env.h"
+#include "rocksdb/iterator.h"
+#include "rocksdb/options.h"
+#include "table/internal_iterator.h"
+#include "table/iterator_wrapper.h"
+#include "util/user_comparator_wrapper.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+Status ArenaWrappedDBIter::GetProperty(std::string prop_name,
+                                       std::string* prop) {
+  if (prop_name == "rocksdb.iterator.super-version-number") {
+    // First try to pass the value returned from inner iterator.
+    if (!db_iter_->GetProperty(prop_name, prop).ok()) {
+      *prop = ToString(sv_number_);
+    }
+    return Status::OK();
+  }
+  return db_iter_->GetProperty(prop_name, prop);
+}
+
+void ArenaWrappedDBIter::Init(Env* env, const ReadOptions& read_options,
+                              const ImmutableCFOptions& cf_options,
+                              const MutableCFOptions& mutable_cf_options,
+                              const SequenceNumber& sequence,
+                              uint64_t max_sequential_skip_in_iteration,
+                              uint64_t version_number,
+                              ReadCallback* read_callback, DBImpl* db_impl,
+                              ColumnFamilyData* cfd, bool allow_blob,
+                              bool allow_refresh) {
+  auto mem = arena_.AllocateAligned(sizeof(DBIter));
+  db_iter_ = new (mem) DBIter(env, read_options, cf_options, mutable_cf_options,
+                              cf_options.user_comparator, nullptr, sequence,
+                              true, max_sequential_skip_in_iteration,
+                              read_callback, db_impl, cfd, allow_blob);
+  sv_number_ = version_number;
+  allow_refresh_ = allow_refresh;
+}
+
+Status ArenaWrappedDBIter::Refresh() {
+  if (cfd_ == nullptr || db_impl_ == nullptr || !allow_refresh_) {
+    return Status::NotSupported("Creating renew iterator is not allowed.");
+  }
+  assert(db_iter_ != nullptr);
+  // TODO(yiwu): For last_seq_same_as_publish_seq_==false, this is not the
+  // correct behavior. Will be corrected automatically when we take a snapshot
+  // here for the case of WritePreparedTxnDB.
+  SequenceNumber latest_seq = db_impl_->GetLatestSequenceNumber();
+  uint64_t cur_sv_number = cfd_->GetSuperVersionNumber();
+  if (sv_number_ != cur_sv_number) {
+    Env* env = db_iter_->env();
+    db_iter_->~DBIter();
+    arena_.~Arena();
+    new (&arena_) Arena();
+
+    SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_);
+    if (read_callback_) {
+      read_callback_->Refresh(latest_seq);
+    }
+    Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
+         latest_seq, sv->mutable_cf_options.max_sequential_skip_in_iterations,
+         cur_sv_number, read_callback_, db_impl_, cfd_, allow_blob_,
+         allow_refresh_);
+
+    InternalIterator* internal_iter = db_impl_->NewInternalIterator(
+        read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator(),
+        latest_seq);
+    SetIterUnderDBIter(internal_iter);
+  } else {
+    db_iter_->set_sequence(latest_seq);
+    db_iter_->set_valid(false);
+  }
+  return Status::OK();
+}
+
+ArenaWrappedDBIter* NewArenaWrappedDbIterator(
+    Env* env, const ReadOptions& read_options,
+    const ImmutableCFOptions& cf_options,
+    const MutableCFOptions& mutable_cf_options, const SequenceNumber& sequence,
+    uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
+    ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
+    bool allow_blob, bool allow_refresh) {
+  ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
+  iter->Init(env, read_options, cf_options, mutable_cf_options, sequence,
+             max_sequential_skip_in_iterations, version_number, read_callback,
+             db_impl, cfd, allow_blob, allow_refresh);
+  if (db_impl != nullptr && cfd != nullptr && allow_refresh) {
+    iter->StoreRefreshInfo(read_options, db_impl, cfd, read_callback,
+                           allow_blob);
+  }
+
+  return iter;
+}
+
+}  // namespace ROCKSDB_NAMESPACE