Add LuaData, a reference type that restores itself over Lua resets. This

works only with static data types that can be restored: tables, strings,
numbers, and not functions, userdata, etc.

stepmania/src/LuaManager.cpp

@@ -202,7 +202,11 @@ LuaManager::~LuaManager()
 void LuaManager::ResetState()
 {
 	if( L != NULL )
+	{
+		LuaReference::BeforeResetAll();
+
 		lua_close( L );
+	}
 
 	L = lua_open();
 	ASSERT( L );
@@ -212,6 +216,7 @@ void LuaManager::ResetState()
 	luaopen_base( L );
 	luaopen_math( L );
 	luaopen_string( L );
+	luaopen_table( L );
 	lua_settop(L, 0); // luaopen_* pushes stuff onto the stack that we don't need
 
 	for( const LuaFunctionList *p = g_LuaFunctions; p; p=p->next )
@@ -226,7 +231,7 @@ void LuaManager::ResetState()
 		}
 	}
 
-	LuaReference::ReRegisterAll();
+	LuaReference::AfterResetAll();
 }
 
 void LuaManager::PrepareExpression( CString &sInOut )

stepmania/src/LuaReference.cpp

@@ -3,6 +3,7 @@
 #include "LuaManager.h"
 #include "LuaBinding.h"
 #include "Foreach.h"
+#include "RageLog.h"
 #include "SubscriptionManager.h"
 
 template<>
@@ -74,10 +75,6 @@ int LuaReference::GetLuaType() const
 	return iRet;
 }
 
-void LuaReference::Register()
-{
-}
-
 void LuaReference::Unregister()
 {
 	if( LUA == NULL )
@@ -87,7 +84,15 @@ void LuaReference::Unregister()
 	m_iReference = LUA_NOREF;
 }
 
-void LuaReference::ReRegisterAll()
+void LuaReference::BeforeResetAll()
+{
+	if( SubscriptionManager<LuaReference>::s_pSubscribers == NULL )
+		return;
+	FOREACHS( LuaReference*, *SubscriptionManager<LuaReference>::s_pSubscribers, p )
+		(*p)->BeforeReset();
+}
+
+void LuaReference::AfterResetAll()
 {
 	if( SubscriptionManager<LuaReference>::s_pSubscribers == NULL )
 		return;
@@ -120,6 +125,44 @@ void LuaExpression::Register()
 	this->SetFromStack();
 }
 
+void LuaData::BeforeReset()
+{
+	/* Call Serialize(t), where t is our referenced object. */
+	this->PushSelf( LUA->L );
+
+	lua_pushstring( LUA->L, "Serialize" );
+	lua_gettable( LUA->L, LUA_GLOBALSINDEX );
+
+	if( lua_isnil(LUA->L, -1) )
+		FAIL_M( "Serialize() missing" );
+
+	lua_call( LUA->L, 0, 1 );
+
+	/* The return value is a string, which we store in m_sSerializedData. */
+	const char *pString = lua_tostring( LUA->L, -1 );
+	if( pString == NULL )
+		FAIL_M( "Serialize() didn't return a string" );
+
+	m_sSerializedData = pString;
+}
+
+void LuaData::Register()
+{
+	/* Restore the serialized data by evaluating the serialized data. */
+	CString sError;
+	if( !LUA->RunScript( m_sSerializedData, "serialization", sError, 1 ) )
+	{
+		/* Serialize() should never return an invalid script.  Drop the failed
+		 * script into the log (it may be too big to pass to FAIL_M) and fail. */
+		LOG->Warn( "Unserialization of \"%s\" failed: %s", m_sSerializedData.c_str(), sError.c_str() );
+		FAIL_M( "Unserialization failed" );
+	}
+
+	this->SetFromStack();
+
+	m_sSerializedData.clear();
+}
+
 /*
  * (c) 2005 Glenn Maynard, Chris Danford
  * All rights reserved.

stepmania/src/LuaReference.h

@@ -29,13 +29,17 @@ public:
 	/* Return the referenced type, or LUA_TNONE if not set. */
 	int GetLuaType() const;
 
-	static void ReRegisterAll();	// call this after resetting Lua
+	static void BeforeResetAll();	// call this before resetting Lua
+	static void AfterResetAll();	// call this after resetting Lua
 
 protected:
+	/* If this object needs to store state to recreate itself, overload this. */
+	virtual void BeforeReset() { }
+
 	/* If this object is able to recreate itself, overload this, and ReRegisterAll
 	 * will work; the reference will still exist after a theme change.  If not
 	 * implemented, the reference will be unset after ReRegister. */
-	virtual void Register();
+	virtual void Register() { }
 
 private:
 	void Unregister();
@@ -57,6 +61,17 @@ private:
 	CString m_sExpression;
 };
 
+/* Reference a trivially restorable Lua object (any object that Serialize can handle).
+ * The object will be saved and restored across Lua resets. */
+class LuaData: public LuaReference
+{
+protected:
+	virtual void BeforeReset();
+	virtual void Register();
+
+	CString m_sSerializedData;
+};
+
 #endif
 
 /*