UniversalMachExcServer: eliminate multiple implementation inheritance

tools/catch_exception_tool.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // 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,
@@ skipping 29 matching lines @@
 
 struct Options {
   std::string file_path;
   std::string mach_service;
   FILE* file;
   int timeout_secs;
   MachMessageServer::Nonblocking nonblocking;
   MachMessageServer::Persistent persistent;
 };
 
-class ExceptionServer : public UniversalMachExcServer {
+class ExceptionServer : public UniversalMachExcServer::Interface {
  public:
   ExceptionServer(const Options& options,
                   const std::string& me,
                   int* exceptions_handled)
-      : UniversalMachExcServer(),
+      : UniversalMachExcServer::Interface(),
         options_(options),
         me_(me),
         exceptions_handled_(exceptions_handled) {}
 
+  // UniversalMachExcServer::Interface:
   virtual kern_return_t CatchMachException(
       exception_behavior_t behavior,
       exception_handler_t exception_port,
       thread_t thread,
       task_t task,
       exception_type_t exception,
       const mach_exception_data_type_t* code,
       mach_msg_type_number_t code_count,
       thread_state_flavor_t* flavor,
       const natural_t* old_state,
@@ skipping 198 matching lines @@
     file_owner.reset(fopen(options.file_path.c_str(), "a"));
     if (!file_owner.get()) {
       PLOG(ERROR) << "fopen " << options.file_path;
       return EXIT_FAILURE;
     }
     options.file = file_owner.get();
   }
 
   int exceptions_handled = 0;
   ExceptionServer exception_server(options, me, &exceptions_handled);
+  UniversalMachExcServer universal_mach_exc_server(&exception_server);
 
   // Assume that if persistent mode has been requested, it’s desirable to ignore
   // large messages and keep running.
   MachMessageServer::ReceiveLarge receive_large =
       (options.persistent == MachMessageServer::kPersistent)
           ? MachMessageServer::kReceiveLargeIgnore
           : MachMessageServer::kReceiveLargeError;
 
   mach_msg_timeout_t timeout_ms = options.timeout_secs
                                       ? options.timeout_secs * 1000
                                       : MACH_MSG_TIMEOUT_NONE;
 
-  mach_msg_return_t mr = MachMessageServer::Run(&exception_server,
+  mach_msg_return_t mr = MachMessageServer::Run(&universal_mach_exc_server,
                                                 service_port,
                                                 MACH_MSG_OPTION_NONE,
                                                 options.persistent,
                                                 options.nonblocking,
                                                 receive_large,
                                                 timeout_ms);
   if (mr == MACH_RCV_TIMED_OUT && options.timeout_secs && options.persistent &&
       exceptions_handled) {
     // This is not an error: when exiting on timeout during persistent
     // processing and at least one exception was handled, it’s considered a
     // success.
   } else if (mr != MACH_MSG_SUCCESS) {
     MACH_LOG(ERROR, mr) << "MachMessageServer::Run";
     return EXIT_FAILURE;
   }
 
   return EXIT_SUCCESS;
 }
 
 }  // namespace
 }  // namespace crashpad
 
 int main(int argc, char* argv[]) {
   return crashpad::CatchExceptionToolMain(argc, argv);
 }