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authorvitalyisaev <vitalyisaev@yandex-team.com>2023-06-29 10:00:50 +0300
committervitalyisaev <vitalyisaev@yandex-team.com>2023-06-29 10:00:50 +0300
commit6ffe9e53658409f212834330e13564e4952558f6 (patch)
tree85b1e00183517648b228aafa7c8fb07f5276f419 /contrib/libs/llvm14/include/llvm/ADT/BreadthFirstIterator.h
parent726057070f9c5a91fc10fde0d5024913d10f1ab9 (diff)
downloadydb-6ffe9e53658409f212834330e13564e4952558f6.tar.gz
YQ Connector: support managed ClickHouse
Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.
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+#pragma once
+
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+//===- llvm/ADT/BreadthFirstIterator.h - Breadth First iterator -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file builds on the ADT/GraphTraits.h file to build a generic breadth
+/// first graph iterator. This file exposes the following functions/types:
+///
+/// bf_begin/bf_end/bf_iterator
+/// * Normal breadth-first iteration - visit a graph level-by-level.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_BREADTHFIRSTITERATOR_H
+#define LLVM_ADT_BREADTHFIRSTITERATOR_H
+
+#include "llvm/ADT/GraphTraits.h"
+#include "llvm/ADT/None.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/iterator_range.h"
+#include <iterator>
+#include <queue>
+#include <utility>
+
+namespace llvm {
+
+// bf_iterator_storage - A private class which is used to figure out where to
+// store the visited set. We only provide a non-external variant for now.
+template <class SetType> class bf_iterator_storage {
+public:
+ SetType Visited;
+};
+
+// The visited state for the iteration is a simple set.
+template <typename NodeRef, unsigned SmallSize = 8>
+using bf_iterator_default_set = SmallPtrSet<NodeRef, SmallSize>;
+
+// Generic Breadth first search iterator.
+template <class GraphT,
+ class SetType =
+ bf_iterator_default_set<typename GraphTraits<GraphT>::NodeRef>,
+ class GT = GraphTraits<GraphT>>
+class bf_iterator : public bf_iterator_storage<SetType> {
+public:
+ using iterator_category = std::forward_iterator_tag;
+ using value_type = typename GT::NodeRef;
+ using difference_type = std::ptrdiff_t;
+ using pointer = value_type *;
+ using reference = value_type &;
+
+private:
+ using NodeRef = typename GT::NodeRef;
+ using ChildItTy = typename GT::ChildIteratorType;
+
+ // First element is the node reference, second is the next child to visit.
+ using QueueElement = std::pair<NodeRef, Optional<ChildItTy>>;
+
+ // Visit queue - used to maintain BFS ordering.
+ // Optional<> because we need markers for levels.
+ std::queue<Optional<QueueElement>> VisitQueue;
+
+ // Current level.
+ unsigned Level = 0;
+
+ inline bf_iterator(NodeRef Node) {
+ this->Visited.insert(Node);
+ Level = 0;
+
+ // Also, insert a dummy node as marker.
+ VisitQueue.push(QueueElement(Node, None));
+ VisitQueue.push(None);
+ }
+
+ inline bf_iterator() = default;
+
+ inline void toNext() {
+ Optional<QueueElement> Head = VisitQueue.front();
+ QueueElement H = Head.getValue();
+ NodeRef Node = H.first;
+ Optional<ChildItTy> &ChildIt = H.second;
+
+ if (!ChildIt)
+ ChildIt.emplace(GT::child_begin(Node));
+ while (*ChildIt != GT::child_end(Node)) {
+ NodeRef Next = *(*ChildIt)++;
+
+ // Already visited?
+ if (this->Visited.insert(Next).second)
+ VisitQueue.push(QueueElement(Next, None));
+ }
+ VisitQueue.pop();
+
+ // Go to the next element skipping markers if needed.
+ if (!VisitQueue.empty()) {
+ Head = VisitQueue.front();
+ if (Head != None)
+ return;
+ Level += 1;
+ VisitQueue.pop();
+
+ // Don't push another marker if this is the last
+ // element.
+ if (!VisitQueue.empty())
+ VisitQueue.push(None);
+ }
+ }
+
+public:
+ // Provide static begin and end methods as our public "constructors"
+ static bf_iterator begin(const GraphT &G) {
+ return bf_iterator(GT::getEntryNode(G));
+ }
+
+ static bf_iterator end(const GraphT &G) { return bf_iterator(); }
+
+ bool operator==(const bf_iterator &RHS) const {
+ return VisitQueue == RHS.VisitQueue;
+ }
+
+ bool operator!=(const bf_iterator &RHS) const { return !(*this == RHS); }
+
+ const NodeRef &operator*() const { return VisitQueue.front()->first; }
+
+ // This is a nonstandard operator-> that dereferences the pointer an extra
+ // time so that you can actually call methods on the node, because the
+ // contained type is a pointer.
+ NodeRef operator->() const { return **this; }
+
+ bf_iterator &operator++() { // Pre-increment
+ toNext();
+ return *this;
+ }
+
+ bf_iterator operator++(int) { // Post-increment
+ bf_iterator ItCopy = *this;
+ ++*this;
+ return ItCopy;
+ }
+
+ unsigned getLevel() const { return Level; }
+};
+
+// Provide global constructors that automatically figure out correct types.
+template <class T> bf_iterator<T> bf_begin(const T &G) {
+ return bf_iterator<T>::begin(G);
+}
+
+template <class T> bf_iterator<T> bf_end(const T &G) {
+ return bf_iterator<T>::end(G);
+}
+
+// Provide an accessor method to use them in range-based patterns.
+template <class T> iterator_range<bf_iterator<T>> breadth_first(const T &G) {
+ return make_range(bf_begin(G), bf_end(G));
+}
+
+} // end namespace llvm
+
+#endif // LLVM_ADT_BREADTHFIRSTITERATOR_H
+
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif