1 files changed, 66 insertions, 0 deletions
diff --git a/contrib/google-ced/util/varsetter.h b/contrib/google-ced/util/varsetter.h
new file mode 100644
index 0000000..8e8cbf2
--- /dev/null
+++ b/contrib/google-ced/util/varsetter.h
@@ -0,0 +1,66 @@
+// Copyright 2016 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef UTIL_VARSETTER_H_
+#define UTIL_VARSETTER_H_
+
+//
+// Use a VarSetter object to temporarily set an object of some sort to
+// a particular value.  When the VarSetter object is destructed, the
+// underlying object will revert to its former value.
+//
+// Sample code:
+//
+#if 0
+{
+  bool b = true;
+  {
+    VarSetter<bool> bool_setter(&b, false);
+    // Now b == false.
+  }
+  // Now b == true again.
+}
+#endif
+
+template <class C>
+class VarSetter {
+public:
+
+  // Constructor that just sets the object to a fixed value
+  VarSetter(C* object, const C& value) : object_(object), old_value_(*object) {
+    *object = value;
+  }
+
+  ~VarSetter() { *object_ = old_value_; }
+
+private:
+
+  C*const object_;
+  C old_value_;
+
+  // Disallow
+  VarSetter(const VarSetter&);
+  VarSetter& operator=(const VarSetter&);
+
+  // VarSetters always live on the stack
+  static void* operator new (size_t);
+  static void* operator new[](size_t);  // Redundant, no default ctor
+
+  static void operator delete (void*);
+  static void operator delete[](void*);
+};
+
+#endif  // UTIL_VARSETTER_H_