3becc9409e
Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/13113 The patch makes some small improvements related to `allow_unprepared_value` and multi-CF iterators as groundwork for further changes: 1) Similarly to `BaseDeltaIterator`'s base iterator, `MultiCfIteratorImpl` gets passed its child iterators by the client. Even though they are currently guaranteed to have been created using the same read options as each other and the multi-CF iterator, it is safer to not assume this and call `PrepareValue` unconditionally before using any child iterator's `value()` or `columns()`. 2) Again similarly to `BaseDeltaIterator`, it makes sense to pass the entire `ReadOptions` structure to `MultiCfIteratorImpl` in case it turns out to require other read options in the future. 3) The constructors of the various multi-CF iterator classes now take an rvalue reference to a vector of column family handle + `unique_ptr` to child iterator pairs and use move semantics to take ownership of this vector (instead of taking two separate vectors of column family handles and raw iterator pointers). 4) Constructor arguments and the members of `MultiCfIteratorImpl` are reordered for consistency. Reviewed By: jowlyzhang Differential Revision: D65407521 fbshipit-source-id: 66c2c689ec8b036740bd98641b7b5c0ff7e777f2
108 lines
3.3 KiB
C++
108 lines
3.3 KiB
C++
// Copyright (c) Meta Platforms, Inc. and affiliates.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#include "db/multi_cf_iterator_impl.h"
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#include "rocksdb/attribute_groups.h"
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namespace ROCKSDB_NAMESPACE {
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class AttributeGroupIteratorImpl : public AttributeGroupIterator {
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public:
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AttributeGroupIteratorImpl(
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const ReadOptions& read_options, const Comparator* comparator,
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std::vector<std::pair<ColumnFamilyHandle*, std::unique_ptr<Iterator>>>&&
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cfh_iter_pairs)
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: impl_(read_options, comparator, std::move(cfh_iter_pairs),
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ResetFunc(this), PopulateFunc(this)) {}
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~AttributeGroupIteratorImpl() override {}
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// No copy allowed
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AttributeGroupIteratorImpl(const AttributeGroupIteratorImpl&) = delete;
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AttributeGroupIteratorImpl& operator=(const AttributeGroupIteratorImpl&) =
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delete;
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bool Valid() const override { return impl_.Valid(); }
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void SeekToFirst() override { impl_.SeekToFirst(); }
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void SeekToLast() override { impl_.SeekToLast(); }
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void Seek(const Slice& target) override { impl_.Seek(target); }
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void SeekForPrev(const Slice& target) override { impl_.SeekForPrev(target); }
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void Next() override { impl_.Next(); }
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void Prev() override { impl_.Prev(); }
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Slice key() const override { return impl_.key(); }
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Status status() const override { return impl_.status(); }
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const IteratorAttributeGroups& attribute_groups() const override {
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assert(Valid());
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return attribute_groups_;
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}
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void Reset() { attribute_groups_.clear(); }
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bool PrepareValue() override { return impl_.PrepareValue(); }
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private:
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class ResetFunc {
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public:
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explicit ResetFunc(AttributeGroupIteratorImpl* iter) : iter_(iter) {}
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void operator()() const {
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assert(iter_);
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iter_->Reset();
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}
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private:
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AttributeGroupIteratorImpl* iter_;
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};
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class PopulateFunc {
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public:
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explicit PopulateFunc(AttributeGroupIteratorImpl* iter) : iter_(iter) {}
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void operator()(const autovector<MultiCfIteratorInfo>& items) const {
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assert(iter_);
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iter_->AddToAttributeGroups(items);
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}
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private:
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AttributeGroupIteratorImpl* iter_;
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};
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MultiCfIteratorImpl<ResetFunc, PopulateFunc> impl_;
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IteratorAttributeGroups attribute_groups_;
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void AddToAttributeGroups(const autovector<MultiCfIteratorInfo>& items);
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};
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class EmptyAttributeGroupIterator : public AttributeGroupIterator {
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public:
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explicit EmptyAttributeGroupIterator(const Status& s) : status_(s) {}
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bool Valid() const override { return false; }
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void Seek(const Slice& /*target*/) override {}
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void SeekForPrev(const Slice& /*target*/) override {}
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void SeekToFirst() override {}
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void SeekToLast() override {}
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void Next() override { assert(false); }
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void Prev() override { assert(false); }
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Slice key() const override {
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assert(false);
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return Slice();
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}
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Status status() const override { return status_; }
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const IteratorAttributeGroups& attribute_groups() const override {
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return kNoIteratorAttributeGroups;
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}
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private:
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Status status_;
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};
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inline std::unique_ptr<AttributeGroupIterator> NewAttributeGroupErrorIterator(
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const Status& status) {
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return std::make_unique<EmptyAttributeGroupIterator>(status);
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}
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} // namespace ROCKSDB_NAMESPACE
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