be compatible with log4cxx 0.11 and 0.12/0.13

[`log4cxx` uses `std::shared_ptr`](https://issues.apache.org/jira/browse/LOGCXX-486)
since [version `0.12`](https://logging.apache.org/log4cxx/latest_stable/changelog.html)

Unfortunately Ubuntu 22.04 ships with
[`0.12`](https://packages.ubuntu.com/jammy/liblog4cxx12), which means
that rosconsole with the `log4cxx` backend wouldn't compile. This is
also a problem on other distros such as Arch or Gentoo.

I have carefully applied explicit construction/conversion and `&*`
instead of `.get()` to make the code compile with both versions of
`log4cxx`.

Author: dreuter

src/rosconsole/impl/rosconsole_log4cxx.cpp

@@ -166,7 +166,7 @@ void initialize()
   }
 
   log4cxx::LoggerPtr logger = log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME);
-  logger->addAppender(new ROSConsoleStdioAppender);
+  logger->addAppender(log4cxx::AppenderPtr(new ROSConsoleStdioAppender));
 #ifdef _MSC_VER
   if ( ros_root_cstr != NULL ) {
 	  free(ros_root_cstr);
@@ -200,7 +200,7 @@ bool isEnabledFor(void* handle, ::ros::console::Level level)
 
 void* getHandle(const std::string& name)
 {
-  return log4cxx::Logger::getLogger(name);
+  return &*log4cxx::Logger::getLogger(name);
 }
 
 std::string getName(void* handle)
@@ -216,7 +216,7 @@ std::string getName(void* handle)
 
 bool get_loggers(std::map<std::string, levels::Level>& loggers)
 {
-  log4cxx::spi::LoggerRepositoryPtr repo = log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME)->getLoggerRepository();
+  auto repo = log4cxx::spi::LoggerRepositoryPtr(log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME)->getLoggerRepository());
 
   log4cxx::LoggerList current_loggers = repo->getCurrentLoggers();
   log4cxx::LoggerList::iterator it = current_loggers.begin();
@@ -352,22 +352,21 @@ class Log4cxxAppender : public log4cxx::AppenderSkeleton
   ros::console::LogAppender* appender_;
 };
 
-Log4cxxAppender* g_log4cxx_appender = 0;
+log4cxx::AppenderPtr g_log4cxx_appender = {};
 
 void register_appender(LogAppender* appender)
 {
-  g_log4cxx_appender = new Log4cxxAppender(appender);
+  g_log4cxx_appender = log4cxx::AppenderPtr( new Log4cxxAppender(appender));
   const log4cxx::LoggerPtr& logger = log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME);
   logger->addAppender(g_log4cxx_appender);
 }
 
 void deregister_appender(LogAppender* appender){
-  if(g_log4cxx_appender->getAppender() == appender)
+  if(dynamic_cast<Log4cxxAppender*>(&*g_log4cxx_appender)->getAppender() == appender)
   {
     const log4cxx::LoggerPtr& logger = log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME);
     logger->removeAppender(g_log4cxx_appender);
-    delete g_log4cxx_appender;
-    g_log4cxx_appender = 0;
+    g_log4cxx_appender = log4cxx::AppenderPtr();
   }
 }
 void shutdown()
@@ -376,14 +375,14 @@ void shutdown()
   {
     const log4cxx::LoggerPtr& logger = log4cxx::Logger::getLogger(ROSCONSOLE_ROOT_LOGGER_NAME);
     logger->removeAppender(g_log4cxx_appender);
-    g_log4cxx_appender = 0;
+    g_log4cxx_appender = log4cxx::AppenderPtr();
   }
   // reset this so that the logger doesn't get crashily destroyed
   // again during global destruction.  
   //
   // See https://code.ros.org/trac/ros/ticket/3271
   //
-  log4cxx::Logger::getRootLogger()->getLoggerRepository()->shutdown();
+  static_cast<log4cxx::spi::LoggerRepositoryPtr>(log4cxx::Logger::getRootLogger()->getLoggerRepository())->shutdown();
 }
 
 } // namespace impl

test/thread_test.cpp

@@ -95,7 +95,7 @@ TEST(Rosconsole, threadedCalls)
 {
   log4cxx::LoggerPtr logger = log4cxx::Logger::getLogger(ROSCONSOLE_DEFAULT_NAME);
 
-  TestAppender* appender = new TestAppender;
+  auto appender = log4cxx::AppenderPtr(new TestAppender);
   logger->addAppender( appender );
 
   boost::thread_group tg;
@@ -106,7 +106,7 @@ TEST(Rosconsole, threadedCalls)
   }
   tg.join_all();
 
-  ASSERT_EQ(appender->info_.size(), 10ULL);
+  ASSERT_EQ(dynamic_cast<TestAppender*>(&*appender)->info_.size(), 10ULL);
 
   logger->removeAppender(appender);
 }