1 files changed, 48 insertions, 0 deletions
diff --git a/include/clang/Tooling/ASTDiff/ASTDiffInternal.h b/include/clang/Tooling/ASTDiff/ASTDiffInternal.h
new file mode 100644
index 000000000000..a76ad37336a6
--- /dev/null
+++ b/include/clang/Tooling/ASTDiff/ASTDiffInternal.h
@@ -0,0 +1,48 @@
+//===- ASTDiffInternal.h --------------------------------------*- C++ -*- -===//
+//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLING_ASTDIFF_ASTDIFFINTERNAL_H
+#define LLVM_CLANG_TOOLING_ASTDIFF_ASTDIFFINTERNAL_H
+
+#include "clang/AST/ASTTypeTraits.h"
+
+namespace clang {
+namespace diff {
+
+using DynTypedNode = ast_type_traits::DynTypedNode;
+
+class SyntaxTree;
+class SyntaxTreeImpl;
+struct ComparisonOptions;
+
+/// Within a tree, this identifies a node by its preorder offset.
+struct NodeId {
+private:
+  static constexpr int InvalidNodeId = -1;
+
+public:
+  int Id;
+
+  NodeId() : Id(InvalidNodeId) {}
+  NodeId(int Id) : Id(Id) {}
+
+  operator int() const { return Id; }
+  NodeId &operator++() { return ++Id, *this; }
+  NodeId &operator--() { return --Id, *this; }
+  // Support defining iterators on NodeId.
+  NodeId &operator*() { return *this; }
+
+  bool isValid() const { return Id != InvalidNodeId; }
+  bool isInvalid() const { return Id == InvalidNodeId; }
+};
+
+} // end namespace diff
+} // end namespace clang
+#endif