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46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
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// Copyright (c) 2015, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#include "rocksdb/types.h"
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namespace rocksdb {
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class DB;
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// Abstract handle to particular state of a DB.
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// A Snapshot is an immutable object and can therefore be safely
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// accessed from multiple threads without any external synchronization.
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//
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// To Create a Snapshot, call DB::GetSnapshot().
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// To Destroy a Snapshot, call DB::ReleaseSnapshot(snapshot).
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class Snapshot {
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public:
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// returns Snapshot's sequence number
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virtual SequenceNumber GetSequenceNumber() const = 0;
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protected:
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virtual ~Snapshot();
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};
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// Simple RAII wrapper class for Snapshot.
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// Constructing this object will create a snapshot. Destructing will
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// release the snapshot.
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class ManagedSnapshot {
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public:
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explicit ManagedSnapshot(DB* db);
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~ManagedSnapshot();
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const Snapshot* snapshot();
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private:
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DB* db_;
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const Snapshot* snapshot_;
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};
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} // namespace rocksdb
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