Shut down mapgen threads before other shutdown tasks (#6689)

Solves some issues with ModStorage functionality in mapgen threads
that occurred when mapgen threads continued to run after the main
server thread had stopped. Also shuts down mapgen threads before
shutdown callbacks are called.

diff --git a/src/server.cpp b/src/server.cpp
index 653441b54213b0233938bd544e79f3b7b4e6b9a8..26b3bb4b164eb35d052d4c86b7798993823cd147 100644 (file)
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -306,7 +306,7 @@ Server::Server(
 
 Server::~Server()
 {
-       infostream<<"Server destructing"<<std::endl;
+       infostream << "Server destructing" << std::endl;
 
        // Send shutdown message
        SendChatMessage(PEER_ID_INEXISTENT, ChatMessage(CHATMESSAGE_TYPE_ANNOUNCE,
@@ -314,10 +314,7 @@ Server::~Server()
 
        {
                MutexAutoLock envlock(m_env_mutex);
-
-               // Execute script shutdown hooks
-               m_script->on_shutdown();
-
+               
                infostream << "Server: Saving players" << std::endl;
                m_env->saveLoadedPlayers();
 
@@ -333,6 +330,20 @@ Server::~Server()
                }
                m_env->kickAllPlayers(SERVER_ACCESSDENIED_SHUTDOWN,
                        kick_msg, reconnect);
+       }
+
+       // Do this before stopping the server in case mapgen callbacks need to access
+       // server-controlled resources (like ModStorages). Also do them before
+       // shutdown callbacks since they may modify state that is finalized in a
+       // callback.
+       m_emerge->stopThreads();
+
+       {
+               MutexAutoLock envlock(m_env_mutex);
+
+               // Execute script shutdown hooks
+               infostream << "Executing shutdown hooks" << std::endl;
+               m_script->on_shutdown();
 
                infostream << "Server: Saving environment metadata" << std::endl;
                m_env->saveMeta();
@@ -342,10 +353,6 @@ Server::~Server()
        stop();
        delete m_thread;
 
-       // stop all emerge threads before deleting players that may have
-       // requested blocks to be emerged
-       m_emerge->stopThreads();
-
        // Delete things in the reverse order of creation
        delete m_emerge;
        delete m_env;
@@ -357,7 +364,7 @@ Server::~Server()
        delete m_craftdef;
 
        // Deinitialize scripting
-       infostream<<"Server: Deinitializing scripting"<<std::endl;
+       infostream << "Server: Deinitializing scripting" << std::endl;
        delete m_script;
 
        // Delete detached inventories