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rocksdb/table/iterator.cc

130 lines
4.2 KiB

// 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 "rocksdb/iterator.h"
#include "memory/arena.h"
#include "table/internal_iterator.h"
#include "table/iterator_wrapper.h"
namespace ROCKSDB_NAMESPACE {
Status Iterator::GetProperty(std::string prop_name, std::string* prop) {
if (prop == nullptr) {
return Status::InvalidArgument("prop is nullptr");
}
if (prop_name == "rocksdb.iterator.is-key-pinned") {
*prop = "0";
return Status::OK();
}
return Status::InvalidArgument("Unidentified property.");
}
namespace {
class EmptyIterator : public Iterator {
public:
explicit EmptyIterator(const Status& s) : status_(s) {}
bool Valid() const override { return false; }
void Seek(const Slice& /*target*/) override {}
void SeekForPrev(const Slice& /*target*/) override {}
void SeekToFirst() override {}
void SeekToLast() override {}
void Next() override { assert(false); }
void Prev() override { assert(false); }
Slice key() const override {
assert(false);
return Slice();
}
Slice value() const override {
assert(false);
return Slice();
}
Status status() const override { return status_; }
private:
Status status_;
};
template <class TValue = Slice>
class EmptyInternalIterator : public InternalIteratorBase<TValue> {
public:
explicit EmptyInternalIterator(const Status& s) : status_(s) {}
bool Valid() const override { return false; }
void Seek(const Slice& /*target*/) override {}
void SeekForPrev(const Slice& /*target*/) override {}
void SeekToFirst() override {}
void SeekToLast() override {}
void Next() override { assert(false); }
void Prev() override { assert(false); }
Slice key() const override {
assert(false);
return Slice();
}
TValue value() const override {
assert(false);
return TValue();
}
Status status() const override { return status_; }
private:
Status status_;
};
} // namespace
Iterator* NewEmptyIterator() { return new EmptyIterator(Status::OK()); }
Iterator* NewErrorIterator(const Status& status) {
return new EmptyIterator(status);
}
template <class TValue>
InternalIteratorBase<TValue>* NewErrorInternalIterator(const Status& status) {
return new EmptyInternalIterator<TValue>(status);
}
template InternalIteratorBase<IndexValue>* NewErrorInternalIterator(
const Status& status);
template InternalIteratorBase<Slice>* NewErrorInternalIterator(
const Status& status);
template <class TValue>
InternalIteratorBase<TValue>* NewErrorInternalIterator(const Status& status,
Arena* arena) {
if (arena == nullptr) {
return NewErrorInternalIterator<TValue>(status);
} else {
auto mem = arena->AllocateAligned(sizeof(EmptyInternalIterator<TValue>));
return new (mem) EmptyInternalIterator<TValue>(status);
}
}
template InternalIteratorBase<IndexValue>* NewErrorInternalIterator(
const Status& status, Arena* arena);
template InternalIteratorBase<Slice>* NewErrorInternalIterator(
const Status& status, Arena* arena);
template <class TValue>
InternalIteratorBase<TValue>* NewEmptyInternalIterator() {
return new EmptyInternalIterator<TValue>(Status::OK());
}
template InternalIteratorBase<IndexValue>* NewEmptyInternalIterator();
template InternalIteratorBase<Slice>* NewEmptyInternalIterator();
template <class TValue>
InternalIteratorBase<TValue>* NewEmptyInternalIterator(Arena* arena) {
if (arena == nullptr) {
return NewEmptyInternalIterator<TValue>();
} else {
auto mem = arena->AllocateAligned(sizeof(EmptyInternalIterator<TValue>));
return new (mem) EmptyInternalIterator<TValue>(Status::OK());
}
}
template InternalIteratorBase<IndexValue>* NewEmptyInternalIterator(
Arena* arena);
template InternalIteratorBase<Slice>* NewEmptyInternalIterator(Arena* arena);
} // namespace ROCKSDB_NAMESPACE