Add a minimal logging interface and implementation.

Change-Id: Ie65dac4b9e2a77e5118231fde002f78dd33226c5
diff --git a/src/macros.h b/src/macros.h
new file mode 100644
index 0000000..d75f700
--- /dev/null
+++ b/src/macros.h
@@ -0,0 +1,33 @@
+// Copyright 2010 Google
+// 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 SRC_MACROS_H_
+#define SRC_MACROS_H_
+
+// DISALLOW_COPY_AND_ASSIGN disallows the copy and operator= functions.
+// It goes in the private: declarations in a class.
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);               \
+  void operator=(const TypeName&)
+
+// A macro to disallow all the implicit constructors, namely the
+// default constructor, copy constructor and operator= functions.
+//
+// This should be used in the private: declarations for a class
+// that wants to prevent anyone from instantiating it. This is
+// especially useful for classes containing only static methods.
+#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \
+  TypeName();                                    \
+  DISALLOW_COPY_AND_ASSIGN(TypeName)
+
+#endif  // SRC_MACROS_H_