ReadView.h

#pragma once
 
#include <xrpl/basics/chrono.h>
#include <xrpl/beast/hash/uhash.h>
#include <xrpl/ledger/detail/ReadViewFwdRange.h>
#include <xrpl/protocol/Fees.h>
#include <xrpl/protocol/IOUAmount.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/LedgerHeader.h>
#include <xrpl/protocol/Protocol.h>
#include <xrpl/protocol/Rules.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STTx.h>
 
#include <cstdint>
#include <optional>
#include <unordered_set>
 
namespace xrpl {
 
//------------------------------------------------------------------------------
 
class ReadView
{
public:
    using tx_type = std::pair<std::shared_ptr<STTx const>, std::shared_ptr<STObject const>>;
 
    using key_type = uint256;
 
    using mapped_type = std::shared_ptr<SLE const>;
 
    struct sles_type : detail::ReadViewFwdRange<std::shared_ptr<SLE const>>
    {
        explicit sles_type(ReadView const& view);
        iterator
        begin() const;
        iterator
        end() const;
        iterator
        upper_bound(key_type const& key) const;
    };
 
    struct txs_type : detail::ReadViewFwdRange<tx_type>
    {
        explicit txs_type(ReadView const& view);
        bool
        empty() const;
        iterator
        begin() const;
        iterator
        end() const;
    };
 
    virtual ~ReadView() = default;
 
    ReadView&
    operator=(ReadView&& other) = delete;
    ReadView&
    operator=(ReadView const& other) = delete;
 
    ReadView() : sles(*this), txs(*this)
    {
    }
 
    ReadView(ReadView const& other) : sles(*this), txs(*this)
    {
    }
 
    ReadView(ReadView&& other) : sles(*this), txs(*this)
    {
    }
 
    virtual LedgerHeader const&
    header() const = 0;
 
    virtual bool
    open() const = 0;
 
    NetClock::time_point
    parentCloseTime() const
    {
        return header().parentCloseTime;
    }
 
    LedgerIndex
    seq() const
    {
        return header().seq;
    }
 
    virtual Fees const&
    fees() const = 0;
 
    virtual Rules const&
    rules() const = 0;
 
    virtual bool
    exists(Keylet const& k) const = 0;
 
    virtual std::optional<key_type>
    succ(key_type const& key, std::optional<key_type> const& last = std::nullopt) const = 0;
 
    virtual std::shared_ptr<SLE const>
    read(Keylet const& k) const = 0;
 
    // Accounts in a payment are not allowed to use assets acquired during that
    // payment. The PaymentSandbox tracks the debits, credits, and owner count
    // changes that accounts make during a payment. `balanceHook` adjusts
    // balances so newly acquired assets are not counted toward the balance.
    // This is required to support PaymentSandbox.
    virtual STAmount
    balanceHook(AccountID const& account, AccountID const& issuer, STAmount const& amount) const
    {
        return amount;
    }
 
    // Accounts in a payment are not allowed to use assets acquired during that
    // payment. The PaymentSandbox tracks the debits, credits, and owner count
    // changes that accounts make during a payment. `ownerCountHook` adjusts the
    // ownerCount so it returns the max value of the ownerCount so far.
    // This is required to support PaymentSandbox.
    virtual std::uint32_t
    ownerCountHook(AccountID const& account, std::uint32_t count) const
    {
        return count;
    }
 
    // used by the implementation
    virtual std::unique_ptr<sles_type::iter_base>
    slesBegin() const = 0;
 
    // used by the implementation
    virtual std::unique_ptr<sles_type::iter_base>
    slesEnd() const = 0;
 
    // used by the implementation
    virtual std::unique_ptr<sles_type::iter_base>
    slesUpperBound(key_type const& key) const = 0;
 
    // used by the implementation
    virtual std::unique_ptr<txs_type::iter_base>
    txsBegin() const = 0;
 
    // used by the implementation
    virtual std::unique_ptr<txs_type::iter_base>
    txsEnd() const = 0;
 
    virtual bool
    txExists(key_type const& key) const = 0;
 
    virtual tx_type
    txRead(key_type const& key) const = 0;
 
    //
    // Memberspaces
    //
 
    sles_type sles;
 
    // The range of transactions
    txs_type txs;
};
 
//------------------------------------------------------------------------------
 
class DigestAwareReadView : public ReadView
{
public:
    using digest_type = uint256;
 
    DigestAwareReadView() = default;
    DigestAwareReadView(DigestAwareReadView const&) = default;
 
    virtual std::optional<digest_type>
    digest(key_type const& key) const = 0;
};
 
//------------------------------------------------------------------------------
 
Rules
makeRulesGivenLedger(DigestAwareReadView const& ledger, Rules const& current);
 
Rules
makeRulesGivenLedger(DigestAwareReadView const& ledger, std::unordered_set<uint256, beast::uhash<>> const& presets);
 
}  // namespace xrpl
 
#include <xrpl/ledger/detail/ReadViewFwdRange.ipp>