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110 lines
3.9 KiB
C++
110 lines
3.9 KiB
C++
//------------------------------------------------------------------------------
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/*
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This file is part of clio: https://github.com/XRPLF/clio
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Copyright (c) 2024, the clio developers.
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Permission to use, copy, modify, and 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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#pragma once
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#include "data/BackendInterface.hpp"
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#include "data/Types.hpp"
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#include "etl/impl/BaseCursorProvider.hpp"
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#include "util/Assert.hpp"
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#include <xrpl/basics/base_uint.h>
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#include <algorithm>
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#include <cstddef>
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#include <cstdint>
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#include <iterator>
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#include <memory>
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#include <ranges>
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#include <set>
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#include <vector>
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namespace etl::impl {
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class CursorFromDiffProvider : public BaseCursorProvider {
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std::shared_ptr<BackendInterface> backend_;
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size_t numCursors_;
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public:
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CursorFromDiffProvider(std::shared_ptr<BackendInterface> const& backend, size_t numCursors)
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: backend_{backend}, numCursors_{numCursors}
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{
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}
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[[nodiscard]] std::vector<CursorPair>
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getCursors(uint32_t const seq) const override
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{
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namespace rg = std::ranges;
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namespace vs = std::views;
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auto const fetchDiff = [this, seq](uint32_t offset) {
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return data::synchronousAndRetryOnTimeout([this, seq, offset](auto yield) {
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return backend_->fetchLedgerDiff(seq - offset, yield);
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});
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};
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auto const range = backend_->fetchLedgerRange();
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ASSERT(range.has_value(), "Ledger range is not available when cache is loading");
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std::set<ripple::uint256> liveCursors;
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std::set<ripple::uint256> deletedCursors;
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auto i = 0;
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while (liveCursors.size() < numCursors_ and seq - i >= range->minSequence) {
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auto diffs = fetchDiff(i++);
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rg::copy(
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diffs //
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| vs::filter([&deletedCursors](auto const& obj) {
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return not obj.blob.empty() and !deletedCursors.contains(obj.key);
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}) //
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| vs::transform([](auto const& obj) { return obj.key; }),
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std::inserter(liveCursors, std::begin(liveCursors))
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);
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// track the deleted objects
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rg::copy(
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diffs //
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| vs::filter([](auto const& obj) { return obj.blob.empty(); }) //
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| vs::transform([](auto const& obj) { return obj.key; }),
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std::inserter(deletedCursors, std::begin(deletedCursors))
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);
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}
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std::vector<ripple::uint256> cursors{data::firstKey};
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rg::copy(liveCursors | vs::take(std::min(liveCursors.size(), numCursors_)), std::back_inserter(cursors));
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rg::sort(cursors);
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cursors.push_back(data::lastKey);
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std::vector<CursorPair> pairs;
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pairs.reserve(cursors.size());
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// FIXME: this should be `cursors | vs::pairwise` (C++23)
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std::transform(
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std::begin(cursors),
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std::prev(std::end(cursors)),
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std::next(std::begin(cursors)),
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std::back_inserter(pairs),
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[](auto&& a, auto&& b) -> CursorPair { return {a, b}; }
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);
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return pairs;
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}
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};
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} // namespace etl::impl
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