6189230202
Summary: Closes https://github.com/facebook/rocksdb/pull/2589 Differential Revision: D5431502 Pulled By: siying fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75
107 lines
3.2 KiB
C++
107 lines
3.2 KiB
C++
// 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.
|
|
|
|
#pragma once
|
|
|
|
#include <set>
|
|
|
|
#include "table/internal_iterator.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
// A internal wrapper class with an interface similar to Iterator that caches
|
|
// the valid() and key() results for an underlying iterator.
|
|
// This can help avoid virtual function calls and also gives better
|
|
// cache locality.
|
|
class IteratorWrapper {
|
|
public:
|
|
IteratorWrapper() : iter_(nullptr), valid_(false) {}
|
|
explicit IteratorWrapper(InternalIterator* _iter) : iter_(nullptr) {
|
|
Set(_iter);
|
|
}
|
|
~IteratorWrapper() {}
|
|
InternalIterator* iter() const { return iter_; }
|
|
|
|
// Set the underlying Iterator to _iter and return
|
|
// previous underlying Iterator.
|
|
InternalIterator* Set(InternalIterator* _iter) {
|
|
InternalIterator* old_iter = iter_;
|
|
|
|
iter_ = _iter;
|
|
if (iter_ == nullptr) {
|
|
valid_ = false;
|
|
} else {
|
|
Update();
|
|
}
|
|
return old_iter;
|
|
}
|
|
|
|
void DeleteIter(bool is_arena_mode) {
|
|
if (iter_) {
|
|
if (!is_arena_mode) {
|
|
delete iter_;
|
|
} else {
|
|
iter_->~InternalIterator();
|
|
}
|
|
}
|
|
}
|
|
|
|
// Iterator interface methods
|
|
bool Valid() const { return valid_; }
|
|
Slice key() const { assert(Valid()); return key_; }
|
|
Slice value() const { assert(Valid()); return iter_->value(); }
|
|
// Methods below require iter() != nullptr
|
|
Status status() const { assert(iter_); return iter_->status(); }
|
|
void Next() { assert(iter_); iter_->Next(); Update(); }
|
|
void Prev() { assert(iter_); iter_->Prev(); Update(); }
|
|
void Seek(const Slice& k) { assert(iter_); iter_->Seek(k); Update(); }
|
|
void SeekForPrev(const Slice& k) {
|
|
assert(iter_);
|
|
iter_->SeekForPrev(k);
|
|
Update();
|
|
}
|
|
void SeekToFirst() { assert(iter_); iter_->SeekToFirst(); Update(); }
|
|
void SeekToLast() { assert(iter_); iter_->SeekToLast(); Update(); }
|
|
|
|
void SetPinnedItersMgr(PinnedIteratorsManager* pinned_iters_mgr) {
|
|
assert(iter_);
|
|
iter_->SetPinnedItersMgr(pinned_iters_mgr);
|
|
}
|
|
bool IsKeyPinned() const {
|
|
assert(Valid());
|
|
return iter_->IsKeyPinned();
|
|
}
|
|
bool IsValuePinned() const {
|
|
assert(Valid());
|
|
return iter_->IsValuePinned();
|
|
}
|
|
|
|
private:
|
|
void Update() {
|
|
valid_ = iter_->Valid();
|
|
if (valid_) {
|
|
key_ = iter_->key();
|
|
}
|
|
}
|
|
|
|
InternalIterator* iter_;
|
|
bool valid_;
|
|
Slice key_;
|
|
};
|
|
|
|
class Arena;
|
|
// Return an empty iterator (yields nothing) allocated from arena.
|
|
extern InternalIterator* NewEmptyInternalIterator(Arena* arena);
|
|
|
|
// Return an empty iterator with the specified status, allocated arena.
|
|
extern InternalIterator* NewErrorInternalIterator(const Status& status,
|
|
Arena* arena);
|
|
|
|
} // namespace rocksdb
|