From 8e4c10298489096ad106c8314a54c3f94db0bdac Mon Sep 17 00:00:00 2001
From: Louvenarde <louve@louve.systems>
Date: Sat, 14 Aug 2021 00:27:19 +0200
Subject: [PATCH] Sound mutex workaround

---
 src/Components/Loader.cpp                |  1 +
 src/Components/Loader.hpp                |  1 +
 src/Components/Modules/SoundMutexFix.cpp | 43 ++++++++++++++++++++++++
 src/Components/Modules/SoundMutexFix.hpp | 14 ++++++++
 4 files changed, 59 insertions(+)
 create mode 100644 src/Components/Modules/SoundMutexFix.cpp
 create mode 100644 src/Components/Modules/SoundMutexFix.hpp

diff --git a/src/Components/Loader.cpp b/src/Components/Loader.cpp
index 30819a9f..c6b86290 100644
--- a/src/Components/Loader.cpp
+++ b/src/Components/Loader.cpp
@@ -101,6 +101,7 @@ namespace Components
 		Loader::Register(new StructuredData());
 		Loader::Register(new ConnectProtocol());
 		Loader::Register(new StartupMessages());
+		Loader::Register(new SoundMutexFix());
 
 		Loader::Register(new Client());
 
diff --git a/src/Components/Loader.hpp b/src/Components/Loader.hpp
index 589f256a..998e71e8 100644
--- a/src/Components/Loader.hpp
+++ b/src/Components/Loader.hpp
@@ -130,5 +130,6 @@ namespace Components
 #include "Modules/ConnectProtocol.hpp"
 #include "Modules/StartupMessages.hpp"
 #include "Modules/Stats.hpp"
+#include "Modules/SoundMutexFix.hpp"
 
 #include "Modules/Client.hpp"
\ No newline at end of file
diff --git a/src/Components/Modules/SoundMutexFix.cpp b/src/Components/Modules/SoundMutexFix.cpp
new file mode 100644
index 00000000..b80f936c
--- /dev/null
+++ b/src/Components/Modules/SoundMutexFix.cpp
@@ -0,0 +1,43 @@
+#include "STDInclude.hpp"
+
+namespace Components
+{
+	/// This component is a workaround for issue https://github.com/XLabsProject/iw4x-client/issues/80
+	/// In case the link goes down, this is a "game hangs randomly" issue:
+	/// 
+	/// Investigations on the issue pointed out it comes from a situation on Intel processors where
+	///		WaitForSingleObjectA is ignored by a thread, for some (?) reason.
+	/// 
+	/// This locks up the game randomly, mostly at the end of rounds or when too many things happen at
+	///		once, due to trying to stop sounds (AIL_Stop_sounds) and playing streams at the same time,
+	///		rushing for the same resource via AIL_lock_mutex. 
+	/// 
+	/// This bug has been reproduced on	mp_terminal, mp_overgrown, mp_rust, with and without bots,
+	///		and so far this has been the only way to circumvent it afaik. This component wraps
+	///		miles' mutex into another mutex, created below, and for some reason (?) that mutex is 
+	///		respected when miles' is not.
+	/// 
+	/// As soon as a real fix is found, please discard this fix. In the meantime, it should not
+	///		have side effects too bad - worst case it might cause a slight performance drop during
+	///		team switch and intermission.
+	/// 
+
+	std::mutex SoundMutexFix::snd_mutex;
+
+	static void __stdcall LockSoundMutex(int unk)
+	{
+		std::lock_guard lock(SoundMutexFix::snd_mutex);
+
+		DWORD funcPtr = *reinterpret_cast<DWORD*>(0x6D7554); // AIL_close_stream
+		((void(__stdcall*)(int unk))(funcPtr))(unk);
+	}
+
+	SoundMutexFix::SoundMutexFix()
+	{
+		Utils::Hook(0x689EFE, &LockSoundMutex, HOOK_JUMP).install()->quick();
+	}
+
+	SoundMutexFix::~SoundMutexFix()
+	{
+	}
+}
\ No newline at end of file
diff --git a/src/Components/Modules/SoundMutexFix.hpp b/src/Components/Modules/SoundMutexFix.hpp
new file mode 100644
index 00000000..3e6e2b20
--- /dev/null
+++ b/src/Components/Modules/SoundMutexFix.hpp
@@ -0,0 +1,14 @@
+#pragma once
+
+namespace Components
+{
+	class SoundMutexFix : public Component
+	{
+	public:
+		SoundMutexFix();
+		~SoundMutexFix();
+
+		static void SND_StopStreamChannelHook(int channel);
+		static std::mutex snd_mutex;
+	};
+}