ReadView.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_LEDGER_READVIEW_H_INCLUDED
#define RIPPLE_LEDGER_READVIEW_H_INCLUDED
 
#include <ripple/basics/FeeUnits.h>
#include <ripple/basics/IOUAmount.h>
#include <ripple/basics/XRPAmount.h>
#include <ripple/basics/chrono.h>
#include <ripple/beast/hash/uhash.h>
#include <ripple/beast/utility/Journal.h>
#include <ripple/ledger/detail/ReadViewFwdRange.h>
#include <ripple/protocol/Indexes.h>
#include <ripple/protocol/Protocol.h>
#include <ripple/protocol/STAmount.h>
#include <ripple/protocol/STLedgerEntry.h>
#include <ripple/protocol/STTx.h>
#include <boost/optional.hpp>
#include <cassert>
#include <cstdint>
#include <memory>
#include <unordered_set>
 
namespace ripple {
 
struct Fees
{
    XRPAmount base{0};       // Reference tx cost (drops)
    FeeUnit32 units{0};      // Reference fee units
    XRPAmount reserve{0};    // Reserve base (drops)
    XRPAmount increment{0};  // Reserve increment (drops)
 
    explicit Fees() = default;
    Fees(Fees const&) = default;
    Fees&
    operator=(Fees const&) = default;
 
    XRPAmount
    accountReserve(std::size_t ownerCount) const
    {
        return reserve + ownerCount * increment;
    }
 
    XRPAmount
    toDrops(FeeUnit64 const& fee) const
    {
        if (auto const resultPair = mulDiv(base, fee, units); resultPair.first)
            return resultPair.second;
 
        return XRPAmount(STAmount::cMaxNativeN);
    }
};
 
//------------------------------------------------------------------------------
 
struct LedgerInfo
{
    explicit LedgerInfo() = default;
 
    //
    // For all ledgers
    //
 
    LedgerIndex seq = 0;
    NetClock::time_point parentCloseTime = {};
 
    //
    // For closed ledgers
    //
 
    // Closed means "tx set already determined"
    uint256 hash = beast::zero;
    uint256 txHash = beast::zero;
    uint256 accountHash = beast::zero;
    uint256 parentHash = beast::zero;
 
    XRPAmount drops = beast::zero;
 
    // If validated is false, it means "not yet validated."
    // Once validated is true, it will never be set false at a later time.
    // VFALCO TODO Make this not mutable
    bool mutable validated = false;
    bool accepted = false;
 
    // flags indicating how this ledger close took place
    int closeFlags = 0;
 
    // the resolution for this ledger close time (2-120 seconds)
    NetClock::duration closeTimeResolution = {};
 
    // For closed ledgers, the time the ledger
    // closed. For open ledgers, the time the ledger
    // will close if there's no transactions.
    //
    NetClock::time_point closeTime = {};
};
 
//------------------------------------------------------------------------------
 
class DigestAwareReadView;
 
class Rules
{
private:
    class Impl;
 
    std::shared_ptr<Impl const> impl_;
 
public:
    Rules(Rules const&) = default;
    Rules&
    operator=(Rules const&) = default;
 
    Rules() = delete;
 
    explicit Rules(std::unordered_set<uint256, beast::uhash<>> const& presets);
 
    explicit Rules(
        DigestAwareReadView const& ledger,
        std::unordered_set<uint256, beast::uhash<>> const& presets);
 
    bool
    enabled(uint256 const& id) const;
 
    bool
    changed(DigestAwareReadView const& ledger) const;
 
    bool
    operator==(Rules const&) const;
 
    bool
    operator!=(Rules const& other) const
    {
        return !(*this == other);
    }
};
 
//------------------------------------------------------------------------------
 
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 LedgerInfo const&
    info() const = 0;
 
    virtual bool
    open() const = 0;
 
    NetClock::time_point
    parentCloseTime() const
    {
        return info().parentCloseTime;
    }
 
    LedgerIndex
    seq() const
    {
        return info().seq;
    }
 
    virtual Fees const&
    fees() const = 0;
 
    virtual Rules const&
    rules() const = 0;
 
    virtual bool
    exists(Keylet const& k) const = 0;
 
    virtual boost::optional<key_type>
    succ(
        key_type const& key,
        boost::optional<key_type> const& last = boost::none) 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(const DigestAwareReadView&) = default;
 
    virtual boost::optional<digest_type>
    digest(key_type const& key) const = 0;
};
 
//------------------------------------------------------------------------------
 
// ledger close flags
static std::uint32_t const sLCF_NoConsensusTime = 0x01;
 
inline bool
getCloseAgree(LedgerInfo const& info)
{
    return (info.closeFlags & sLCF_NoConsensusTime) == 0;
}
 
void
addRaw(LedgerInfo const&, Serializer&);
 
}  // namespace ripple
 
#include <ripple/ledger/detail/ReadViewFwdRange.ipp>
 
#endif