From fa1dc98103344ad23d030885be34d0e6d2ab832a Mon Sep 17 00:00:00 2001
From: phosit <phosit@wildfiregames.com>
Date: Sun, 23 Jun 2024 17:26:03 +0000
Subject: [PATCH] Shutdown mongoose in rl-interface gracefully

When the `RL::Interface` is destroied but the engine isn't completely
shoutdown there was a dangling pointer. The time the dangling pointer is
accessable got expanded with 968e55704a.
Whith this patch there no dangling pointer (in that regard).

Accepted by: @vladislavbelov
Comments by: @Stan, @sera
Trac Tickets: #5989

Differential Revision: https://code.wildfiregames.com/D5254
This was SVN commit r28123.
---
 source/rlinterface/RLInterface.cpp | 13 +++++++++----
 source/rlinterface/RLInterface.h   |  7 +++++--
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/source/rlinterface/RLInterface.cpp b/source/rlinterface/RLInterface.cpp
index bd449c9a75..2a7f7a1510 100644
--- a/source/rlinterface/RLInterface.cpp
+++ b/source/rlinterface/RLInterface.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2023 Wildfire Games.
+/* Copyright (C) 2024 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -40,7 +40,7 @@
 
 namespace RL
 {
-Interface::Interface(const char* server_address) : m_GameMessage({GameMessageType::None})
+Interface::Interface(const char* server_address)
 {
 	LOGMESSAGERENDER("Starting RL interface HTTP server");
 
@@ -49,8 +49,13 @@ Interface::Interface(const char* server_address) : m_GameMessage({GameMessageTyp
 		"num_threads", "1",
 		nullptr
 	};
-	mg_context* mgContext = mg_start(MgCallback, this, options);
-	ENSURE(mgContext);
+	m_Context = mg_start(MgCallback, this, options);
+	ENSURE(m_Context);
+}
+
+Interface::~Interface()
+{
+	mg_stop(m_Context);
 }
 
 // Interactions with the game engine (g_Game) must be done in the main
diff --git a/source/rlinterface/RLInterface.h b/source/rlinterface/RLInterface.h
index adbc836a12..ef93885d99 100644
--- a/source/rlinterface/RLInterface.h
+++ b/source/rlinterface/RLInterface.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2023 Wildfire Games.
+/* Copyright (C) 2024 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -84,6 +84,7 @@ class Interface
 	NONCOPYABLE(Interface);
 public:
 	Interface(const char* server_address);
+	~Interface();
 
 	/**
 	 * Non-blocking call to process any pending messages from the RL client.
@@ -149,7 +150,7 @@ private:
 	std::string GetGameState() const;
 
 private:
-	GameMessage m_GameMessage;
+	GameMessage m_GameMessage{GameMessageType::None};
 	ScenarioConfig m_ScenarioConfig;
 	std::string m_ReturnValue;
 	bool m_NeedsGameState = false;
@@ -158,6 +159,8 @@ private:
 	std::mutex m_MsgLock;
 	std::condition_variable m_MsgApplied;
 	std::string m_Code;
+
+	mg_context* m_Context;
 };
 
 }