Pull new version of protobuf sources.

third_party/protobuf/src/google/protobuf/proto_cast.h

 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Author: rennie@google.com (Jeffrey Rennie)
-
-#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
-#define GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
+#ifndef GOOGLE_PROTOBUF_UTIL_PROTO_CAST_H__
+#define GOOGLE_PROTOBUF_UTIL_PROTO_CAST_H__
 
 #include <string>
 
 #include <google/protobuf/stubs/common.h>
+
+// proto_cast<> is used to simulate over-the-wire conversion of one
+// proto message into another.  This is primarily useful for unit tests
+// which validate the version-compatibility semantics of protobufs.
+// Usage is similar to C++-style typecasts:
+//
+// OldMessage old_message = /*...*/;
+// NewMessage new_message = proto_cast<NewMessage>(old_message);
 namespace google {
-namespace protobuf {
-namespace compiler {
-namespace cpp {
+template<typename NewProto,
+         typename OldProto>
+NewProto proto_cast(const OldProto& old_proto) {
+  string wire_format;
+  GOOGLE_CHECK(old_proto.SerializeToString(&wire_format));
 
-// Generator options:
-struct Options {
-  Options() : safe_boundary_check(false) {
-  }
-  string dllexport_decl;
-  bool safe_boundary_check;
-};
-
-}  // namespace cpp
-}  // namespace compiler
-}  // namespace protobuf
-
+  NewProto new_proto;
+  GOOGLE_CHECK(new_proto.ParseFromString(wire_format));
+  return new_proto;
+}
 
 }  // namespace google
-#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_OPTIONS_H__
+#endif  // GOOGLE_PROTOBUF_UTIL_PROTO_CAST_H__