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- /*
- * Tencent is pleased to support the open source community by making wwsearch
- * available.
- *
- * Copyright (C) 2018-present Tencent. All Rights Reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- * https://opensource.org/licenses/Apache-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OF ANY KIND, either express or implied. See the License for the
- * specific language governing permissions and limitations under the License.
- */
- // 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 "iterator_rocks.h"
- #include "search_slice.h"
- #include "search_status.h"
- namespace wwsearch {
- /* Notice : 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(Iterator* iter) : iter_(nullptr) { Set(iter); }
- ~IteratorWrapper() { delete iter_; }
- Iterator* iter() const { return iter_; }
- // Takes ownership of "iter" and will delete it when destroyed, or
- // when Set() is invoked again.
- void Set(Iterator* iter) {
- delete iter_;
- iter_ = iter;
- if (iter_ == nullptr) {
- valid_ = false;
- } else {
- Update();
- }
- }
- // 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
- SearchStatus 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();
- }
- private:
- void Update() {
- valid_ = iter_->Valid();
- if (valid_) {
- key_ = iter_->key();
- }
- }
- Iterator* iter_;
- bool valid_;
- Slice key_;
- };
- } // namespace wwsearch
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