From 2151bb8f5bad91975010ab1022177fdb94cc2a3e Mon Sep 17 00:00:00 2001
From: madmaxoft <github@xoft.cz>
Date: Tue, 6 Aug 2013 08:01:00 +0200
Subject: [PATCH] cLuaState can now contain a detached LuaState, too.

This will be useful for cases when we get a lua_State * from the outside and are asked to perform operations on it.
---
 source/LuaState.cpp | 67 +++++++++++++++++++++++++++++++++++++++++++++
 source/LuaState.h   | 23 +++++++++++++++-
 2 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/source/LuaState.cpp b/source/LuaState.cpp
index da86a4b20..117023755 100644
--- a/source/LuaState.cpp
+++ b/source/LuaState.cpp
@@ -37,6 +37,7 @@ extern "C"
 
 cLuaState::cLuaState(const AString & a_SubsystemName) :
 	m_LuaState(NULL),
+	m_IsOwned(false),
 	m_SubsystemName(a_SubsystemName)
 {
 }
@@ -45,6 +46,17 @@ cLuaState::cLuaState(const AString & a_SubsystemName) :
 
 
 
+cLuaState::cLuaState(lua_State * a_AttachState) :
+	m_LuaState(a_AttachState),
+	m_IsOwned(false),
+	m_SubsystemName("<attached>")
+{
+}
+
+
+
+
+
 cLuaState::~cLuaState()
 {
 	if (IsValid())
@@ -70,6 +82,7 @@ void cLuaState::Create(void)
 	ManualBindings::Bind(m_LuaState);
 	luaopen_lsqlite3(m_LuaState);
 	luaopen_lxp(m_LuaState);
+	m_IsOwned = true;
 }
 
 
@@ -83,8 +96,62 @@ void cLuaState::Close(void)
 		LOGWARNING("%s: Trying to close an invalid LuaState, ignoring.", __FUNCTION__);
 		return;
 	}
+	if (!m_IsOwned)
+	{
+		LOGWARNING(
+			"%s: Detected mis-use, calling Close() on an attached state (0x%p). Detaching instead.",
+			__FUNCTION__, m_LuaState
+		);
+		Detach();
+		return;
+	}
 	lua_close(m_LuaState);
 	m_LuaState = NULL;
+	m_IsOwned = false;
+}
+
+
+
+
+
+void cLuaState::Attach(lua_State * a_State)
+{
+	if (m_LuaState != NULL)
+	{
+		LOGINFO("%s: Already contains a LuaState (0x%p), will be closed / detached.", __FUNCTION__, m_LuaState);
+		if (m_IsOwned)
+		{
+			Close();
+		}
+		else
+		{
+			Detach();
+		}
+	}
+	m_LuaState = a_State;
+	m_IsOwned = false;
+}
+
+
+
+
+
+void cLuaState::Detach(void)
+{
+	if (m_LuaState == NULL)
+	{
+		return;
+	}
+	if (m_IsOwned)
+	{
+		LOGWARNING(
+			"%s: Detected a mis-use, calling Detach() when the state is owned. Closing the owned state (0x%p).",
+			__FUNCTION__, m_LuaState
+		);
+		Close();
+		return;
+	}
+	m_LuaState = NULL;
 }
 
 
diff --git a/source/LuaState.h b/source/LuaState.h
index 10ff53911..fca532d89 100644
--- a/source/LuaState.h
+++ b/source/LuaState.h
@@ -3,6 +3,12 @@
 
 // Declares the cLuaState class representing the wrapper over lua_State *, provides associated helper functions
 
+/*
+The contained lua_State can be either owned or attached.
+Owned lua_State is created by calling Create() and the cLuaState automatically closes the state
+Or, lua_State can be attached by calling Attach(), the cLuaState doesn't close such a state
+Attaching a state will automatically close an owned state.
+*/
 
 
 
@@ -29,16 +35,28 @@ public:
 	*/
 	cLuaState(const AString & a_SubsystemName);
 	
+	/** Creates a new instance. The a_AttachState is attached.
+	Subsystem name is set to "<attached>".
+	*/
+	explicit cLuaState(lua_State * a_AttachState);
+	
 	~cLuaState();
 	
+	/// Allows this object to be used in the same way as a lua_State *, for example in the LuaLib functions
 	operator lua_State * (void) { return m_LuaState; }
 	
-	/// Creates the m_LuaState, if not closed already
+	/// Creates the m_LuaState, if not closed already. This state will be automatically closed in the destructor
 	void Create(void);
 	
 	/// Closes the m_LuaState, if not closed already
 	void Close(void);
 	
+	/// Attaches the specified state. Operations will be carried out on this state, but it will not be closed in the destructor
+	void Attach(lua_State * a_State);
+	
+	/// Detaches a previously attached state.
+	void Detach(void);
+	
 	/// Returns true if the m_LuaState is valid
 	bool IsValid(void) const { return (m_LuaState != NULL); }
 	
@@ -79,6 +97,9 @@ public:
 protected:
 	lua_State * m_LuaState;
 	
+	/// If true, the state is owned by this object and will be auto-Closed. False => attached state
+	bool m_IsOwned;
+	
 	/** The subsystem name is used for reporting errors to the console, it is either "plugin %s" or "LuaScript"
 	whatever is given to the constructor
 	*/