mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-26 16:30:56 +00:00
c41f1e995c
Summary: scripted NULL to nullptr in * include/leveldb/ * db/ * table/ * util/ Test Plan: make all check Reviewers: dhruba, emayanke Reviewed By: emayanke CC: leveldb Differential Revision: https://reviews.facebook.net/D9003
64 lines
2 KiB
C++
64 lines
2 KiB
C++
// 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.
|
|
|
|
#ifndef STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
|
|
#define STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
|
|
|
|
namespace leveldb {
|
|
|
|
// 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
|
|
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 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 leveldb
|
|
|
|
#endif // STORAGE_LEVELDB_TABLE_ITERATOR_WRAPPER_H_
|