77 lines
3.2 KiB
C++
77 lines
3.2 KiB
C++
/*
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* IVersionedStore.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef FDBSERVER_IVERSIONEDSTORE_H
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#define FDBSERVER_IVERSIONEDSTORE_H
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#pragma once
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#include "fdbserver/IKeyValueStore.h"
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#include "flow/flow.h"
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#include "fdbclient/FDBTypes.h"
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class IStoreCursor {
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public:
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virtual Future<Void> findEqual(KeyRef key) = 0;
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virtual Future<Void> findFirstEqualOrGreater(KeyRef key, bool needValue, int prefetchNextBytes) = 0;
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virtual Future<Void> findLastLessOrEqual(KeyRef key, bool needValue, int prefetchPriorBytes) = 0;
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virtual Future<Void> next(bool needValue) = 0;
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virtual Future<Void> prev(bool needValue) = 0;
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virtual bool isValid() = 0;
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virtual KeyRef getKey() = 0;
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//virtual StringRef getCompressedKey() = 0;
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virtual ValueRef getValue() = 0;
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virtual void invalidateReturnedStrings() = 0;
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virtual void addref() = 0;
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virtual void delref() = 0;
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};
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class IVersionedStore : public IClosable {
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public:
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virtual KeyValueStoreType getType() = 0;
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virtual bool supportsMutation(int op) = 0; // If this returns true, then mutate(op, ...) may be called
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virtual StorageBytes getStorageBytes() = 0;
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// Writes are provided in an ordered stream.
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// A write is considered part of (a change leading to) the version determined by the previous call to setWriteVersion()
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// A write shall not become durable until the following call to commit() begins, and shall be durable once the following call to commit() returns
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virtual void set(KeyValueRef keyValue) = 0;
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virtual void clear(KeyRangeRef range) = 0;
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virtual void mutate(int op, StringRef param1, StringRef param2) = 0;
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virtual void setWriteVersion(Version) = 0; // The write version must be nondecreasing
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virtual void forgetVersions(Version begin, Version end) = 0; // Versions [begin, end) no longer readable
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virtual Future<Void> commit() = 0;
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virtual Future<Version> getLatestVersion() = 0;
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// readAtVersion() may only be called on a version which has previously been passed to setWriteVersion() and never previously passed
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// to forgetVersion. The returned results when violating this precondition are unspecified; the store is not required to be able to detect violations.
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// The returned read cursor provides a consistent snapshot of the versioned store, corresponding to all the writes done with write versions less
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// than or equal to the given version.
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// If readAtVersion() is called on the *current* write version, the given read cursor MAY reflect subsequent writes at the same
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// write version, OR it may represent a snapshot as of the call to readAtVersion().
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virtual Reference<IStoreCursor> readAtVersion(Version) = 0;
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};
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#endif
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