OpenLedger.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_APP_LEDGER_OPENLEDGER_H_INCLUDED
#define RIPPLE_APP_LEDGER_OPENLEDGER_H_INCLUDED
 
#include <xrpld/app/ledger/Ledger.h>
#include <xrpld/app/misc/CanonicalTXSet.h>
#include <xrpld/core/Config.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/UnorderedContainers.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/ledger/CachedSLEs.h>
#include <xrpl/ledger/OpenView.h>
 
#include <mutex>
 
namespace ripple {
 
// How many total extra passes we make
// We must ensure we make at least one non-retriable pass
#define LEDGER_TOTAL_PASSES 3
 
// How many extra retry passes we
// make if the previous retry pass made changes
#define LEDGER_RETRY_PASSES 1
 
using OrderedTxs = CanonicalTXSet;
 
//------------------------------------------------------------------------------
 
class OpenLedger
{
private:
    beast::Journal const j_;
    CachedSLEs& cache_;
    std::mutex mutable modify_mutex_;
    std::mutex mutable current_mutex_;
    std::shared_ptr<OpenView const> current_;
 
public:
    using modify_type = std::function<bool(OpenView&, beast::Journal)>;
 
    OpenLedger() = delete;
    OpenLedger(OpenLedger const&) = delete;
    OpenLedger&
    operator=(OpenLedger const&) = delete;
 
    explicit OpenLedger(
        std::shared_ptr<Ledger const> const& ledger,
        CachedSLEs& cache,
        beast::Journal journal);
 
    bool
    empty() const;
 
    std::shared_ptr<OpenView const>
    current() const;
 
    bool
    modify(modify_type const& f);
 
    void
    accept(
        Application& app,
        Rules const& rules,
        std::shared_ptr<Ledger const> const& ledger,
        OrderedTxs const& locals,
        bool retriesFirst,
        OrderedTxs& retries,
        ApplyFlags flags,
        std::string const& suffix = "",
        modify_type const& f = {});
 
private:
    template <class FwdRange>
    static void
    apply(
        Application& app,
        OpenView& view,
        ReadView const& check,
        FwdRange const& txs,
        OrderedTxs& retries,
        ApplyFlags flags,
        beast::Journal j);
 
    enum Result { success, failure, retry };
 
    std::shared_ptr<OpenView>
    create(Rules const& rules, std::shared_ptr<Ledger const> const& ledger);
 
    static Result
    apply_one(
        Application& app,
        OpenView& view,
        std::shared_ptr<STTx const> const& tx,
        bool retry,
        ApplyFlags flags,
        beast::Journal j);
};
 
//------------------------------------------------------------------------------
 
template <class FwdRange>
void
OpenLedger::apply(
    Application& app,
    OpenView& view,
    ReadView const& check,
    FwdRange const& txs,
    OrderedTxs& retries,
    ApplyFlags flags,
    beast::Journal j)
{
    for (auto iter = txs.begin(); iter != txs.end(); ++iter)
    {
        try
        {
            // Dereferencing the iterator can throw since it may be transformed.
            auto const tx = *iter;
            auto const txId = tx->getTransactionID();
            if (check.txExists(txId))
                continue;
            auto const result = apply_one(app, view, tx, true, flags, j);
            if (result == Result::retry)
                retries.insert(tx);
        }
        catch (std::exception const& e)
        {
            JLOG(j.error())
                << "OpenLedger::apply: Caught exception: " << e.what();
        }
    }
    bool retry = true;
    for (int pass = 0; pass < LEDGER_TOTAL_PASSES; ++pass)
    {
        int changes = 0;
        auto iter = retries.begin();
        while (iter != retries.end())
        {
            switch (apply_one(app, view, iter->second, retry, flags, j))
            {
                case Result::success:
                    ++changes;
                    [[fallthrough]];
                case Result::failure:
                    iter = retries.erase(iter);
                    break;
                case Result::retry:
                    ++iter;
            }
        }
        // A non-retry pass made no changes
        if (!changes && !retry)
            return;
        // Stop retriable passes
        if (!changes || (pass >= LEDGER_RETRY_PASSES))
            retry = false;
    }
 
    // If there are any transactions left, we must have
    // tried them in at least one final pass
    XRPL_ASSERT(
        retries.empty() || !retry, "ripple::OpenLedger::apply : valid retries");
}
 
//------------------------------------------------------------------------------
 
// For debug logging
 
std::string
debugTxstr(std::shared_ptr<STTx const> const& tx);
 
std::string
debugTostr(OrderedTxs const& set);
 
std::string
debugTostr(SHAMap const& set);
 
std::string
debugTostr(std::shared_ptr<ReadView const> const& view);
 
}  // namespace ripple
 
#endif