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af36942e1f
* Clarify use of cancel view in OfferCreate transactor * Reduce OfferStream public interface * Reduce severity of some developer-only logging from ERROR to DEBUG
95 lines
3.1 KiB
C++
95 lines
3.1 KiB
C++
//------------------------------------------------------------------------------
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/*
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This file is part of rippled: https://github.com/ripple/rippled
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Copyright (c) 2014 Ripple Labs Inc.
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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//==============================================================================
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#ifndef RIPPLE_APP_BOOK_OFFERSTREAM_H_INCLUDED
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#define RIPPLE_APP_BOOK_OFFERSTREAM_H_INCLUDED
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#include <ripple/app/tx/impl/BookTip.h>
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#include <ripple/app/tx/impl/Offer.h>
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#include <ripple/ledger/View.h>
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#include <ripple/protocol/Quality.h>
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#include <beast/utility/Journal.h>
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#include <beast/utility/noexcept.h>
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namespace ripple {
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/** Presents and consumes the offers in an order book.
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Two `ApplyView` objects accumulate changes to the ledger. `view`
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is applied when the calling transaction succeeds. If the calling
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transaction fails, then `view_cancel` is applied.
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Certain invalid offers are automatically removed:
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- Offers with missing ledger entries
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- Offers that expired
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- Offers found unfunded:
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An offer is found unfunded when the corresponding balance is zero
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and the caller has not modified the balance. This is accomplished
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by also looking up the balance in the cancel view.
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When an offer is removed, it is removed from both views. This grooms the
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order book regardless of whether or not the transaction is successful.
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*/
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class OfferStream
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{
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private:
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beast::Journal j_;
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ApplyView& view_;
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ApplyView& cancelView_;
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Book book_;
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Clock::time_point const expire_;
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BookTip tip_;
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Offer offer_;
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Config const& config_;
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void
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erase (ApplyView& view);
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public:
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OfferStream (ApplyView& view, ApplyView& cancelView,
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BookRef book, Clock::time_point when,
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Config const& config,
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beast::Journal journal);
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/** Returns the offer at the tip of the order book.
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Offers are always presented in decreasing quality.
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Only valid if step() returned `true`.
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*/
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Offer const&
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tip () const
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{
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return offer_;
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}
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/** Advance to the next valid offer.
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This automatically removes:
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- Offers with missing ledger entries
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- Offers found unfunded
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- expired offers
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@return `true` if there is a valid offer.
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*/
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bool
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step ();
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};
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}
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#endif
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