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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <memory>
#include <shared_mutex>
namespace document { class DocumentTypeRepo; }
namespace storage::mbusprot { class ProtocolSerialization7; }
namespace storage::rpc {
class WrappedCodec {
const std::shared_ptr<const document::DocumentTypeRepo> _doc_type_repo;
std::unique_ptr<mbusprot::ProtocolSerialization7> _codec;
public:
explicit WrappedCodec(std::shared_ptr<const document::DocumentTypeRepo> doc_type_repo);
~WrappedCodec();
[[nodiscard]] const mbusprot::ProtocolSerialization7& codec() const noexcept { return *_codec; }
};
/**
* Thread-safe wrapper around a protocol serialization codec and its transitive
* dependencies. Effectively provides support for setting and getting an immutable
* codec snapshot that can be used for RPC (de-)serialization.
*/
class MessageCodecProvider {
// TODO replace with std::atomic<std::shared_ptr<WrappedCodec>> once on a sufficiently new
// C++20 STL that implements the P0718R2 proposal. We expect(tm) an implementation to use
// lock-free compiler-specific 128-bit CAS atomics instead of explicit locks there.
mutable std::shared_mutex _rw_mutex;
std::shared_ptr<WrappedCodec> _active_codec;
public:
explicit MessageCodecProvider(std::shared_ptr<const document::DocumentTypeRepo> doc_type_repo);
~MessageCodecProvider();
[[nodiscard]] std::shared_ptr<const WrappedCodec> wrapped_codec() const noexcept;
void update_atomically(std::shared_ptr<const document::DocumentTypeRepo> doc_type_repo);
};
}
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