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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
commit | e6918187568dbd01842d8d1d2c808ce16a894239 (patch) | |
tree | 64f88b554b444a49f656b6c656111a145cbbaa28 /src/rocksdb/db/lookup_key.h | |
parent | Initial commit. (diff) | |
download | ceph-upstream/18.2.2.tar.xz ceph-upstream/18.2.2.zip |
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/db/lookup_key.h | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/src/rocksdb/db/lookup_key.h b/src/rocksdb/db/lookup_key.h new file mode 100644 index 000000000..68851bddd --- /dev/null +++ b/src/rocksdb/db/lookup_key.h @@ -0,0 +1,68 @@ +// 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. + +#pragma once +#include <string> +#include <utility> + +#include "rocksdb/slice.h" +#include "rocksdb/types.h" + +namespace ROCKSDB_NAMESPACE { + +// A helper class useful for DBImpl::Get() +class LookupKey { + public: + // Initialize *this for looking up user_key at a snapshot with + // the specified sequence number. + LookupKey(const Slice& _user_key, SequenceNumber sequence, + const Slice* ts = nullptr); + + ~LookupKey(); + + // Return a key suitable for lookup in a MemTable. + Slice memtable_key() const { + return Slice(start_, static_cast<size_t>(end_ - start_)); + } + + // Return an internal key (suitable for passing to an internal iterator) + Slice internal_key() const { + return Slice(kstart_, static_cast<size_t>(end_ - kstart_)); + } + + // Return the user key. + // If user-defined timestamp is enabled, then timestamp is included in the + // result. + Slice user_key() const { + return Slice(kstart_, static_cast<size_t>(end_ - kstart_ - 8)); + } + + private: + // We construct a char array of the form: + // klength varint32 <-- start_ + // userkey char[klength] <-- kstart_ + // tag uint64 + // <-- end_ + // The array is a suitable MemTable key. + // The suffix starting with "userkey" can be used as an InternalKey. + const char* start_; + const char* kstart_; + const char* end_; + char space_[200]; // Avoid allocation for short keys + + // No copying allowed + LookupKey(const LookupKey&); + void operator=(const LookupKey&); +}; + +inline LookupKey::~LookupKey() { + if (start_ != space_) delete[] start_; +} + +} // namespace ROCKSDB_NAMESPACE |