CL for perf tryjob on linux

third_party/cld/base/varsetter.h

+//
+// Copyright (C) 1999 and onwards Google, Inc.
+//
+// Author: Ray Sidney
+//
+#ifndef BASE_VARSETTER_H_
+#define BASE_VARSETTER_H_
+
+//#include "base/port.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  // BASE_VARSETTER_H_