[ADT] Add a sum type abstraction for pointer-like types.

[oota-llvm.git] / include / llvm / ADT / ilist_node.h

diff --git a/include/llvm/ADT/ilist_node.h b/include/llvm/ADT/ilist_node.h
index 9e6031170664001fb15b4ada1f72820b7b08b417..7e5a0e0e5ad81d5867ef6710e65d2649bb84cab4 100644 (file)
--- a/include/llvm/ADT/ilist_node.h
+++ b/include/llvm/ADT/ilist_node.h
@@ -1,10 +1,10 @@
 //==-- llvm/ADT/ilist_node.h - Intrusive Linked List Helper ------*- C++ -*-==//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
-// 
+//
 //===----------------------------------------------------------------------===//
 //
 // This file defines the ilist_node class template, which is a convenient
@@ -17,25 +17,105 @@
 
 namespace llvm {
 
+template<typename NodeTy>
+struct ilist_traits;
+template <typename NodeTy> struct ilist_embedded_sentinel_traits;
+template <typename NodeTy> struct ilist_half_embedded_sentinel_traits;
+
+/// ilist_half_node - Base class that provides prev services for sentinels.
+///
+template<typename NodeTy>
+class ilist_half_node {
+  friend struct ilist_traits<NodeTy>;
+  friend struct ilist_half_embedded_sentinel_traits<NodeTy>;
+  NodeTy *Prev;
+protected:
+  NodeTy *getPrev() { return Prev; }
+  const NodeTy *getPrev() const { return Prev; }
+  void setPrev(NodeTy *P) { Prev = P; }
+  ilist_half_node() : Prev(nullptr) {}
+};
+
 template<typename NodeTy>
 struct ilist_nextprev_traits;
 
+template <typename NodeTy> class ilist_iterator;
+
 /// ilist_node - Base class that provides next/prev services for nodes
 /// that use ilist_nextprev_traits or ilist_default_traits.
 ///
 template<typename NodeTy>
-class ilist_node {
-private:
+class ilist_node : private ilist_half_node<NodeTy> {
   friend struct ilist_nextprev_traits<NodeTy>;
-  NodeTy *Prev, *Next;
-  NodeTy *getPrev() { return Prev; }
+  friend struct ilist_traits<NodeTy>;
+  friend struct ilist_half_embedded_sentinel_traits<NodeTy>;
+  friend struct ilist_embedded_sentinel_traits<NodeTy>;
+  NodeTy *Next;
   NodeTy *getNext() { return Next; }
-  const NodeTy *getPrev() const { return Prev; }
   const NodeTy *getNext() const { return Next; }
-  void setPrev(NodeTy *N) { Prev = N; }
   void setNext(NodeTy *N) { Next = N; }
 protected:
-  ilist_node() : Prev(0), Next(0) {}
+  ilist_node() : Next(nullptr) {}
+
+public:
+  ilist_iterator<NodeTy> getIterator() {
+    // FIXME: Stop downcasting to create the iterator (potential UB).
+    return ilist_iterator<NodeTy>(static_cast<NodeTy *>(this));
+  }
+  ilist_iterator<const NodeTy> getIterator() const {
+    // FIXME: Stop downcasting to create the iterator (potential UB).
+    return ilist_iterator<const NodeTy>(static_cast<const NodeTy *>(this));
+  }
+};
+
+/// An ilist node that can access its parent list.
+///
+/// Requires \c NodeTy to have \a getParent() to find the parent node, and the
+/// \c ParentTy to have \a getSublistAccess() to get a reference to the list.
+template <typename NodeTy, typename ParentTy>
+class ilist_node_with_parent : public ilist_node<NodeTy> {
+protected:
+  ilist_node_with_parent() = default;
+
+private:
+  /// Forward to NodeTy::getParent().
+  ///
+  /// Note: do not use the name "getParent()".  We want a compile error
+  /// (instead of recursion) when the subclass fails to implement \a
+  /// getParent().
+  const ParentTy *getNodeParent() const {
+    return static_cast<const NodeTy *>(this)->getParent();
+  }
+
+public:
+  /// @name Adjacent Node Accessors
+  /// @{
+  /// \brief Get the previous node, or \c nullptr for the list head.
+  NodeTy *getPrevNode() {
+    // Should be separated to a reused function, but then we couldn't use auto
+    // (and would need the type of the list).
+    const auto &List =
+        getNodeParent()->*(ParentTy::getSublistAccess((NodeTy *)nullptr));
+    return List.getPrevNode(*static_cast<NodeTy *>(this));
+  }
+  /// \brief Get the previous node, or \c nullptr for the list head.
+  const NodeTy *getPrevNode() const {
+    return const_cast<ilist_node_with_parent *>(this)->getPrevNode();
+  }
+
+  /// \brief Get the next node, or \c nullptr for the list tail.
+  NodeTy *getNextNode() {
+    // Should be separated to a reused function, but then we couldn't use auto
+    // (and would need the type of the list).
+    const auto &List =
+        getNodeParent()->*(ParentTy::getSublistAccess((NodeTy *)nullptr));
+    return List.getNextNode(*static_cast<NodeTy *>(this));
+  }
+  /// \brief Get the next node, or \c nullptr for the list tail.
+  const NodeTy *getNextNode() const {
+    return const_cast<ilist_node_with_parent *>(this)->getNextNode();
+  }
+  /// @}
 };
 
 } // End llvm namespace