Script: Improve 6560518

The Unicode state is not tracked using a stack instead of a raw boolean. This means that a Unicode script that e.g. updates a non-Unicode script measure will now work properly.

Library/lua/LuaManager.h

@@ -26,15 +26,25 @@ extern "C"
 #include "lauxlib.h"
 }
 
+#include <vector>
+
 class LuaManager
 {
 public:
+	class ScopedLuaState
+	{
+	public:
+		ScopedLuaState(bool unicode) { LuaManager::c_UnicodeStateStack.push_back(unicode); }
+		~ScopedLuaState() { LuaManager::c_UnicodeStateStack.pop_back(); }
+		operator lua_State*() { return LuaManager::c_State; }
+	};
+
 	static void Initialize();
 	static void Finalize();
 
-	static lua_State* GetState(bool unicode) { c_UnicodeState = unicode; return c_State; }
+	static ScopedLuaState GetState(bool unicode) { return ScopedLuaState(unicode); }
 
-	static bool IsUnicodeState() { return c_UnicodeState; }
+	static bool IsUnicodeState() { return c_UnicodeStateStack.back(); }
 
 	static void ReportErrors(const std::wstring& file);
 
@@ -53,9 +63,10 @@ private:
 	static void RegisterMeterWindow(lua_State* L);
 	static void RegisterMeterString(lua_State* L);
 
-	// If set true |true|, Lua strings converted to/from as if they were encoded in UTF-8. Otherwise
-	// Lua strings are treated as if they are encoded in the default system encoding.
-	static bool c_UnicodeState;
+	// If the back of the vector is |true|, Lua strings converted to/from as if they were encoded
+	// in UTF-8. Otherwise Lua strings are treated as if they are encoded in the default system
+	// encoding.
+	static std::vector<bool> c_UnicodeStateStack;
 };
 
 #endif