MusxInstance.h

/*
 * Copyright (C) 2025, Robert Patterson
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#pragma once
 
#include <vector>
#include <memory>
#include <functional>
#include <optional>
#include <type_traits>
#include <utility>
 
#include "Fundamentals.h"
 
namespace musx {
namespace dom {
 
template <typename T>
using MusxInstance = std::shared_ptr<const T>;
 
template <typename T>
using MusxInstanceWeak = std::weak_ptr<const T>;
 
class Document;
class MusicRange;
class EntryInfoPtr;
 
namespace others {
class StaffUsed;
class Staff;
class StaffComposite;
}
 
template <typename T>
class MusxInstanceListBase : public std::vector<MusxInstance<T>>
{
    using VectorType = std::vector<MusxInstance<T>>;
 
public:
    explicit MusxInstanceListBase(const std::weak_ptr<Document>& document, Cmper partId)
        : m_document(document), m_partId(partId) {}
 
    Cmper getRequestedPartId() const { return m_partId; }
 
    std::shared_ptr<Document> getDocument() const
    {
        auto document = m_document.lock();
        MUSX_ASSERT_IF(!document) {
            throw std::logic_error("Document pointer is no longer valid.");
        }
        return document;
    }
 
private:
    std::weak_ptr<Document> m_document;
    Cmper m_partId;
};
 
template <typename T>
class MusxInstanceList : public MusxInstanceListBase<T>
{
public:
    using MusxInstanceListBase<T>::MusxInstanceListBase;
 
    // No helpers by default
};
 
template<>
class MusxInstanceList<others::StaffUsed> : public MusxInstanceListBase<others::StaffUsed>
{
public:
    using MusxInstanceListBase<others::StaffUsed>::MusxInstanceListBase;
 
    MusxInstance<others::Staff> getStaffInstanceAtIndex(size_t index) const;
 
    MusxInstance<others::StaffComposite> getStaffInstanceAtIndex(size_t index, MeasCmper measureId, Edu eduPosition = 0) const;
 
    std::optional<size_t> getIndexForStaff(StaffCmper staffId) const;
 
    StaffCmper getTopStaffId() const;
 
    StaffCmper getBottomStaffId() const;
 
    bool iterateEntries(size_t startIndex, size_t endIndex, const MusicRange& range, std::function<bool(const EntryInfoPtr&)> iterator) const;
};
 
template<class T>
class DeferredReference {
    static_assert(!std::is_reference_v<T>, "T must not be a reference");
    using OwnedT = std::remove_const_t<T>; 
 
public:
    DeferredReference() noexcept = default;
 
    DeferredReference(const T& ref) noexcept : m_ref(&ref) {}
 
    explicit DeferredReference(const T* ptr) noexcept : m_ref(ptr) {}
 
    const T& emplace(OwnedT&& value) noexcept(std::is_nothrow_move_constructible_v<OwnedT>) {
        m_owned.emplace(std::move(value));
        m_ref = std::addressof(*m_owned);
        return *m_ref;
    }
 
    explicit operator bool() const noexcept { return m_ref != nullptr; }
 
    const T& get() const noexcept { return *m_ref; }
 
    const T* operator->() const noexcept { return m_ref; }
 
    const T& operator*() const noexcept { return *m_ref; }
 
private:
    std::optional<OwnedT> m_owned{}; 
    const T* m_ref = nullptr;        
};
 
#ifndef DOXYGEN_SHOULD_IGNORE_THIS
template<class T> DeferredReference(const T&) -> DeferredReference<T>;
template<class T> DeferredReference(const T*) -> DeferredReference<T>;
#endif // DOXYGEN_SHOULD_IGNORE_THIS
 
} // namespace dom
} // namespace musx