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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_METRICS_STRUCTURED_LIB_ARENA_PERSISTENT_PROTO_H_
#define COMPONENTS_METRICS_STRUCTURED_LIB_ARENA_PERSISTENT_PROTO_H_
#include <concepts>
#include <memory>
#include <type_traits>
#include "components/metrics/structured/lib/persistent_proto_internal.h"
#include "third_party/protobuf/src/google/protobuf/message_lite.h"
namespace metrics::structured {
// A PersistentProto that stores T in an arena.
//
// The provided arena must live longer than |this| and doesn't
// take ownership.
//
// See comment in persistent_proto.h and persistent_proto_internal.h for more
// details.
template <class T>
requires(std::derived_from<T, google::protobuf::MessageLite>)
class ArenaPersistentProto : public internal::PersistentProtoInternal {
public:
ArenaPersistentProto(const base::FilePath& path,
base::TimeDelta write_delay,
PersistentProtoInternal::ReadCallback on_read,
PersistentProtoInternal::WriteCallback on_write)
: internal::PersistentProtoInternal(path,
write_delay,
std::move(on_read),
std::move(on_write)) {}
~ArenaPersistentProto() override { DeallocProto(); }
T* get() { return static_cast<T*>(internal::PersistentProtoInternal::get()); }
const T* get() const {
return static_cast<T*>(internal::PersistentProtoInternal::get());
}
T* operator->() { return get(); }
const T* operator->() const { return get(); }
T& operator*() { return *get(); }
const T& operator*() const { return *get(); }
const google::protobuf::Arena* arena() const { return &arena_; }
private:
google::protobuf::MessageLite* GetProto() override {
return google::protobuf::Arena::Create<T>(&arena_);
}
google::protobuf::Arena arena_;
};
} // namespace metrics::structured
#endif // COMPONENTS_METRICS_STRUCTURED_LIB_ARENA_PERSISTENT_PROTO_H_
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