reader.hpp

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// Copyright (c) 2025 Contributors to the Eclipse Foundation
//
// See the NOTICE file(s) distributed with this work for additional
// information regarding copyright ownership.
//
// This program and the accompanying materials are made available under the
// terms of the Apache Software License 2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0, or the MIT license
// which is available at https://opensource.org/licenses/MIT.
//
// SPDX-License-Identifier: Apache-2.0 OR MIT
 
#ifndef IOX2_READER_HPP
#define IOX2_READER_HPP
 
#include "iox2/bb/detail/assertions.hpp"
#include "iox2/bb/expected.hpp"
#include "iox2/entry_handle.hpp"
#include "iox2/entry_handle_error.hpp"
#include "iox2/internal/service_builder_internal.hpp"
#include "iox2/service_type.hpp"
#include "iox2/unique_port_id.hpp"
 
namespace iox2 {
template <ServiceType S, typename KeyType>
class Reader {
  public:
    Reader(Reader&& rhs) noexcept;
    auto operator=(Reader&& rhs) noexcept -> Reader&;
    ~Reader();
 
    Reader(const Reader&) = delete;
    auto operator=(const Reader&) -> Reader& = delete;
 
    auto id() const -> UniqueReaderId;
 
    template <typename ValueType>
    auto entry(const KeyType& key) -> bb::Expected<EntryHandle<S, KeyType, ValueType>, EntryHandleError>;
 
  private:
    template <ServiceType, typename>
    friend class PortFactoryReader;
 
    explicit Reader(iox2_reader_h handle);
    void drop();
 
    iox2_reader_h m_handle = nullptr;
};
 
template <ServiceType S, typename KeyType>
inline Reader<S, KeyType>::Reader(iox2_reader_h handle)
    : m_handle { handle } {
}
 
template <ServiceType S, typename KeyType>
inline void Reader<S, KeyType>::drop() {
    if (m_handle != nullptr) {
// NOTE: false positive; m_handle is initialized in the class itself
#if (defined(__GNUC__) && __GNUC__ == 13 && !defined(__clang__))
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
#endif
        iox2_reader_drop(m_handle);
#if (defined(__GNUC__) && __GNUC__ == 13 && !defined(__clang__))
#pragma GCC diagnostic pop
#endif
        m_handle = nullptr;
    }
}
 
template <ServiceType S, typename KeyType>
inline Reader<S, KeyType>::Reader(Reader&& rhs) noexcept {
    *this = std::move(rhs);
}
 
template <ServiceType S, typename KeyType>
inline auto Reader<S, KeyType>::operator=(Reader&& rhs) noexcept -> Reader& {
    if (this != &rhs) {
        drop();
        m_handle = rhs.m_handle;
        rhs.m_handle = nullptr;
    }
 
    return *this;
}
 
template <ServiceType S, typename KeyType>
inline Reader<S, KeyType>::~Reader() {
    drop();
}
 
template <ServiceType S, typename KeyType>
inline auto Reader<S, KeyType>::id() const -> UniqueReaderId {
    iox2_unique_reader_id_h id_handle = nullptr;
 
    iox2_reader_id(&m_handle, nullptr, &id_handle);
    return UniqueReaderId { id_handle };
}
 
template <ServiceType S, typename KeyType>
template <typename ValueType>
inline auto Reader<S, KeyType>::entry(const KeyType& key)
    -> bb::Expected<EntryHandle<S, KeyType, ValueType>, EntryHandleError> {
    iox2_entry_handle_h entry_handle {};
    const auto type_name = internal::get_type_name<ValueType>();
 
    auto result = iox2_reader_entry(&m_handle,
                                    nullptr,
                                    &entry_handle,
                                    &key,
                                    type_name.unchecked_access().c_str(),
                                    type_name.size(),
                                    sizeof(ValueType),
                                    alignof(ValueType));
 
    if (result == IOX2_OK) {
        return EntryHandle<S, KeyType, ValueType>(entry_handle);
    }
 
    return bb::err(bb::into<EntryHandleError>(result));
}
} // namespace iox2
 
#endif