Dir.h

#pragma once
 
#include <xrpl/basics/base_uint.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/protocol/Keylet.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STVector256.h>
 
#include <cstddef>
#include <iterator>
#include <optional>
#include <vector>
 
namespace xrpl {

class Dir
{
private:
    ReadView const* view_ = nullptr;
    Keylet root_;
    SLE::const_pointer sle_;
    STVector256 const* indexes_ = nullptr;
 
public:
    class ConstIterator;
    using value_type = SLE::const_pointer;
 
    Dir(ReadView const&, Keylet const&);
 
    [[nodiscard]] ConstIterator
    begin() const;
 
    [[nodiscard]] ConstIterator
    end() const;
};
 
class Dir::ConstIterator
{
public:
    using value_type = Dir::value_type;
    using pointer = value_type const*;
    using reference = value_type const&;
    using difference_type = std::ptrdiff_t;
    using iterator_category = std::forward_iterator_tag;
 
    bool
    operator==(ConstIterator const& other) const;
 
    reference
    operator*() const;
 
    pointer
    operator->() const
    {
        return &**this;
    }
 
    ConstIterator&
    operator++();
 
    ConstIterator
    operator++(int);
 
    ConstIterator&
    nextPage();
 
    std::size_t
    pageSize();
 
    Keylet const&
    page() const
    {
        return page_;
    }
 
    UInt256
    index() const
    {
        return index_;
    }
 
private:
    friend class Dir;
 
    ConstIterator(ReadView const& view, Keylet const& root, Keylet const& page)
        : view_(&view), root_(root), page_(page)
    {
    }
 
    ReadView const* view_ = nullptr;
    Keylet root_;
    Keylet page_;
    UInt256 index_;
    std::optional<value_type> mutable cache_;
    SLE::const_pointer sle_;
    STVector256 const* indexes_ = nullptr;
    std::vector<UInt256>::const_iterator it_;
};
 
}  // namespace xrpl