1 //==-- llvm/ADT/ilist.h - Intrusive Linked List Template ---------*- C++ -*-==//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file defines classes to implement an intrusive doubly linked list class
10 // (i.e. each node of the list must contain a next and previous field for the
13 // The ilist class itself should be a plug in replacement for list. This list
14 // replacement does not provide a constant time size() method, so be careful to
15 // use empty() when you really want to know if it's empty.
17 // The ilist class is implemented as a circular list. The list itself contains
18 // a sentinel node, whose Next points at begin() and whose Prev points at
19 // rbegin(). The sentinel node itself serves as end() and rend().
21 //===----------------------------------------------------------------------===//
23 #ifndef LLVM_ADT_ILIST_H
24 #define LLVM_ADT_ILIST_H
26 #include "llvm/ADT/simple_ilist.h"
33 /// Use delete by default for iplist and ilist.
35 /// Specialize this to get different behaviour for ownership-related API. (If
36 /// you really want ownership semantics, consider using std::list or building
37 /// something like \a BumpPtrList.)
39 /// \see ilist_noalloc_traits
40 template <typename NodeTy> struct ilist_alloc_traits {
41 static void deleteNode(NodeTy *V) { delete V; }
44 /// Custom traits to do nothing on deletion.
46 /// Specialize ilist_alloc_traits to inherit from this to disable the
47 /// non-intrusive deletion in iplist (which implies ownership).
49 /// If you want purely intrusive semantics with no callbacks, consider using \a
50 /// simple_ilist instead.
54 /// struct ilist_alloc_traits<MyType> : ilist_noalloc_traits<MyType> {};
56 template <typename NodeTy> struct ilist_noalloc_traits {
57 static void deleteNode(NodeTy *V) {}
60 /// Callbacks do nothing by default in iplist and ilist.
62 /// Specialize this for to use callbacks for when nodes change their list
64 template <typename NodeTy> struct ilist_callback_traits {
65 void addNodeToList(NodeTy *) {}
66 void removeNodeFromList(NodeTy *) {}
68 /// Callback before transferring nodes to this list. The nodes may already be
69 /// in this same list.
70 template <class Iterator>
71 void transferNodesFromList(ilist_callback_traits &OldList, Iterator /*first*/,
77 /// A fragment for template traits for intrusive list that provides default
78 /// node related operations.
80 /// TODO: Remove this layer of indirection. It's not necessary.
81 template <typename NodeTy>
82 struct ilist_node_traits : ilist_alloc_traits<NodeTy>,
83 ilist_callback_traits<NodeTy> {};
85 /// Template traits for intrusive list.
87 /// Customize callbacks and allocation semantics.
88 template <typename NodeTy>
89 struct ilist_traits : public ilist_node_traits<NodeTy> {};
91 /// Const traits should never be instantiated.
92 template <typename Ty> struct ilist_traits<const Ty> {};
94 namespace ilist_detail {
96 template <class T> T &make();
98 /// Type trait to check for a traits class that has a getNext member (as a
99 /// canary for any of the ilist_nextprev_traits API).
100 template <class TraitsT, class NodeT> struct HasGetNext {
103 template <size_t N> struct SFINAE {};
106 static Yes &test(U *I, decltype(I->getNext(&make<NodeT>())) * = 0);
107 template <class> static No &test(...);
110 static const bool value = sizeof(test<TraitsT>(nullptr)) == sizeof(Yes);
113 /// Type trait to check for a traits class that has a createSentinel member (as
114 /// a canary for any of the ilist_sentinel_traits API).
115 template <class TraitsT> struct HasCreateSentinel {
120 static Yes &test(U *I, decltype(I->createSentinel()) * = 0);
121 template <class> static No &test(...);
124 static const bool value = sizeof(test<TraitsT>(nullptr)) == sizeof(Yes);
127 /// Type trait to check for a traits class that has a createNode member.
128 /// Allocation should be managed in a wrapper class, instead of in
130 template <class TraitsT, class NodeT> struct HasCreateNode {
133 template <size_t N> struct SFINAE {};
136 static Yes &test(U *I, decltype(I->createNode(make<NodeT>())) * = 0);
137 template <class> static No &test(...);
140 static const bool value = sizeof(test<TraitsT>(nullptr)) == sizeof(Yes);
143 template <class TraitsT, class NodeT> struct HasObsoleteCustomization {
144 static const bool value = HasGetNext<TraitsT, NodeT>::value ||
145 HasCreateSentinel<TraitsT>::value ||
146 HasCreateNode<TraitsT, NodeT>::value;
149 } // end namespace ilist_detail
151 //===----------------------------------------------------------------------===//
153 /// A wrapper around an intrusive list with callbacks and non-intrusive
156 /// This wraps a purely intrusive list (like simple_ilist) with a configurable
157 /// traits class. The traits can implement callbacks and customize the
158 /// ownership semantics.
160 /// This is a subset of ilist functionality that can safely be used on nodes of
161 /// polymorphic types, i.e. a heterogeneous list with a common base class that
162 /// holds the next/prev pointers. The only state of the list itself is an
163 /// ilist_sentinel, which holds pointers to the first and last nodes in the
165 template <class IntrusiveListT, class TraitsT>
166 class iplist_impl : public TraitsT, IntrusiveListT {
167 typedef IntrusiveListT base_list_type;
170 typedef typename base_list_type::pointer pointer;
171 typedef typename base_list_type::const_pointer const_pointer;
172 typedef typename base_list_type::reference reference;
173 typedef typename base_list_type::const_reference const_reference;
174 typedef typename base_list_type::value_type value_type;
175 typedef typename base_list_type::size_type size_type;
176 typedef typename base_list_type::difference_type difference_type;
177 typedef typename base_list_type::iterator iterator;
178 typedef typename base_list_type::const_iterator const_iterator;
179 typedef typename base_list_type::reverse_iterator reverse_iterator;
181 typename base_list_type::const_reverse_iterator const_reverse_iterator;
184 // TODO: Drop this assertion and the transitive type traits anytime after
185 // v4.0 is branched (i.e,. keep them for one release to help out-of-tree code
188 !ilist_detail::HasObsoleteCustomization<TraitsT, value_type>::value,
189 "ilist customization points have changed!");
191 static bool op_less(const_reference L, const_reference R) { return L < R; }
192 static bool op_equal(const_reference L, const_reference R) { return L == R; }
195 iplist_impl() = default;
197 iplist_impl(const iplist_impl &) = delete;
198 iplist_impl &operator=(const iplist_impl &) = delete;
200 iplist_impl(iplist_impl &&X)
201 : TraitsT(std::move(static_cast<TraitsT &>(X))),
202 IntrusiveListT(std::move(static_cast<IntrusiveListT &>(X))) {}
203 iplist_impl &operator=(iplist_impl &&X) {
204 *static_cast<TraitsT *>(this) = std::move(static_cast<TraitsT &>(X));
205 *static_cast<IntrusiveListT *>(this) =
206 std::move(static_cast<IntrusiveListT &>(X));
210 ~iplist_impl() { clear(); }
212 // Miscellaneous inspection routines.
213 size_type max_size() const { return size_type(-1); }
215 using base_list_type::begin;
216 using base_list_type::end;
217 using base_list_type::rbegin;
218 using base_list_type::rend;
219 using base_list_type::empty;
220 using base_list_type::front;
221 using base_list_type::back;
223 void swap(iplist_impl &RHS) {
224 assert(0 && "Swap does not use list traits callback correctly yet!");
225 base_list_type::swap(RHS);
228 iterator insert(iterator where, pointer New) {
229 this->addNodeToList(New); // Notify traits that we added a node...
230 return base_list_type::insert(where, *New);
233 iterator insert(iterator where, const_reference New) {
234 return this->insert(where, new value_type(New));
237 iterator insertAfter(iterator where, pointer New) {
239 return insert(begin(), New);
241 return insert(++where, New);
244 /// Clone another list.
245 template <class Cloner> void cloneFrom(const iplist_impl &L2, Cloner clone) {
247 for (const_reference V : L2)
251 pointer remove(iterator &IT) {
252 pointer Node = &*IT++;
253 this->removeNodeFromList(Node); // Notify traits that we removed a node...
254 base_list_type::remove(*Node);
258 pointer remove(const iterator &IT) {
260 return remove(MutIt);
263 pointer remove(pointer IT) { return remove(iterator(IT)); }
264 pointer remove(reference IT) { return remove(iterator(IT)); }
266 // erase - remove a node from the controlled sequence... and delete it.
267 iterator erase(iterator where) {
268 this->deleteNode(remove(where));
272 iterator erase(pointer IT) { return erase(iterator(IT)); }
273 iterator erase(reference IT) { return erase(iterator(IT)); }
275 /// Remove all nodes from the list like clear(), but do not call
276 /// removeNodeFromList() or deleteNode().
278 /// This should only be used immediately before freeing nodes in bulk to
279 /// avoid traversing the list and bringing all the nodes into cache.
280 void clearAndLeakNodesUnsafely() { base_list_type::clear(); }
283 // transfer - The heart of the splice function. Move linked list nodes from
284 // [first, last) into position.
286 void transfer(iterator position, iplist_impl &L2, iterator first, iterator last) {
287 if (position == last)
290 // Notify traits we moved the nodes...
291 this->transferNodesFromList(L2, first, last);
293 base_list_type::splice(position, L2, first, last);
297 //===----------------------------------------------------------------------===
298 // Functionality derived from other functions defined above...
301 using base_list_type::size;
303 iterator erase(iterator first, iterator last) {
304 while (first != last)
305 first = erase(first);
309 void clear() { erase(begin(), end()); }
311 // Front and back inserters...
312 void push_front(pointer val) { insert(begin(), val); }
313 void push_back(pointer val) { insert(end(), val); }
315 assert(!empty() && "pop_front() on empty list!");
319 assert(!empty() && "pop_back() on empty list!");
320 iterator t = end(); erase(--t);
323 // Special forms of insert...
324 template<class InIt> void insert(iterator where, InIt first, InIt last) {
325 for (; first != last; ++first) insert(where, *first);
328 // Splice members - defined in terms of transfer...
329 void splice(iterator where, iplist_impl &L2) {
331 transfer(where, L2, L2.begin(), L2.end());
333 void splice(iterator where, iplist_impl &L2, iterator first) {
334 iterator last = first; ++last;
335 if (where == first || where == last) return; // No change
336 transfer(where, L2, first, last);
338 void splice(iterator where, iplist_impl &L2, iterator first, iterator last) {
339 if (first != last) transfer(where, L2, first, last);
341 void splice(iterator where, iplist_impl &L2, reference N) {
342 splice(where, L2, iterator(N));
344 void splice(iterator where, iplist_impl &L2, pointer N) {
345 splice(where, L2, iterator(N));
348 template <class Compare>
349 void merge(iplist_impl &Right, Compare comp) {
352 this->transferNodesFromList(Right, Right.begin(), Right.end());
353 base_list_type::merge(Right, comp);
355 void merge(iplist_impl &Right) { return merge(Right, op_less); }
357 using base_list_type::sort;
359 /// Get the previous node, or \c nullptr for the list head.
360 pointer getPrevNode(reference N) const {
361 auto I = N.getIterator();
364 return &*std::prev(I);
366 /// Get the previous node, or \c nullptr for the list head.
367 const_pointer getPrevNode(const_reference N) const {
368 return getPrevNode(const_cast<reference >(N));
371 /// Get the next node, or \c nullptr for the list tail.
372 pointer getNextNode(reference N) const {
373 auto Next = std::next(N.getIterator());
378 /// Get the next node, or \c nullptr for the list tail.
379 const_pointer getNextNode(const_reference N) const {
380 return getNextNode(const_cast<reference >(N));
384 /// An intrusive list with ownership and callbacks specified/controlled by
385 /// ilist_traits, only with API safe for polymorphic types.
387 /// The \p Options parameters are the same as those for \a simple_ilist. See
388 /// there for a description of what's available.
389 template <class T, class... Options>
391 : public iplist_impl<simple_ilist<T, Options...>, ilist_traits<T>> {
392 using iplist_impl_type = typename iplist::iplist_impl;
397 iplist(const iplist &X) = delete;
398 iplist &operator=(const iplist &X) = delete;
400 iplist(iplist &&X) : iplist_impl_type(std::move(X)) {}
401 iplist &operator=(iplist &&X) {
402 *static_cast<iplist_impl_type *>(this) = std::move(X);
407 template <class T, class... Options> using ilist = iplist<T, Options...>;
409 } // end namespace llvm
413 // Ensure that swap uses the fast list swap...
415 void swap(llvm::iplist<Ty> &Left, llvm::iplist<Ty> &Right) {
419 } // end namespace std
421 #endif // LLVM_ADT_ILIST_H