Allow to mark preferences as immutable or deprecated

- Deprecated: The option is read from the settings, but not written back
  when saving. This can be used for migrating options to a new name or
  format. (Not used yet.)
- Immutable: The option can not be changed from Lua. Used for
  security-relevant options that should not be changable by the theme or
  mod charts. Currently that's networking and some file system access
  options.

src/MemoryCardManager.cpp

@@ -42,14 +42,14 @@ static Preference<bool>	g_bMemoryCards( "MemoryCards", false );
 static Preference<bool>	g_bMemoryCardProfiles( "MemoryCardProfiles", true );
 
 // if set, always use the device that mounts to this point
-Preference1D<RString>		MemoryCardManager::m_sMemoryCardOsMountPoint( MemoryCardOsMountPointInit,	NUM_PLAYERS );
+Preference1D<RString>	MemoryCardManager::m_sMemoryCardOsMountPoint( MemoryCardOsMountPointInit, NUM_PLAYERS, PreferenceType::Immutable );
 
 // Look for this level, bus, port when assigning cards. -1 = match any
-Preference1D<int>		MemoryCardManager::m_iMemoryCardUsbBus( MemoryCardUsbBusInit,			NUM_PLAYERS );
-Preference1D<int>		MemoryCardManager::m_iMemoryCardUsbPort( MemoryCardUsbPortInit,			NUM_PLAYERS );
-Preference1D<int>		MemoryCardManager::m_iMemoryCardUsbLevel( MemoryCardUsbLevelInit,		NUM_PLAYERS );
+Preference1D<int>	MemoryCardManager::m_iMemoryCardUsbBus( MemoryCardUsbBusInit, NUM_PLAYERS, PreferenceType::Immutable );
+Preference1D<int>	MemoryCardManager::m_iMemoryCardUsbPort( MemoryCardUsbPortInit, NUM_PLAYERS, PreferenceType::Immutable );
+Preference1D<int>	MemoryCardManager::m_iMemoryCardUsbLevel( MemoryCardUsbLevelInit, NUM_PLAYERS, PreferenceType::Immutable );
 
-Preference<RString>		MemoryCardManager::m_sEditorMemoryCardOsMountPoint( "EditorMemoryCardOsMountPoint",	"" );
+Preference<RString>	MemoryCardManager::m_sEditorMemoryCardOsMountPoint( "EditorMemoryCardOsMountPoint", "", nullptr, PreferenceType::Immutable );
 
 const RString MEM_CARD_MOUNT_POINT[NUM_PLAYERS] =
 {

src/NetworkManager.cpp

@@ -17,8 +17,8 @@
 
 NetworkManager*	NETWORK = nullptr;	// global and accessible from anywhere in our program
 
-Preference<bool> NetworkManager::httpEnabled("HttpEnabled", false);
-Preference<RString> NetworkManager::httpAllowHosts("HttpAllowHosts", "");
+Preference<bool> NetworkManager::httpEnabled("HttpEnabled", false, nullptr, PreferenceType::Immutable);
+Preference<RString> NetworkManager::httpAllowHosts("HttpAllowHosts", "", nullptr, PreferenceType::Immutable);
 
 static const char *HttpErrorCodeNames[] = {
 	"Blocked",

src/Preference.cpp

@@ -9,9 +9,10 @@
 
 static SubscriptionManager<IPreference> m_Subscribers;
 
-IPreference::IPreference( const RString& sName ):
+IPreference::IPreference( const RString& sName, PreferenceType type ):
 	m_sName( sName ),
-	m_bIsStatic( false )
+	m_bDoNotWrite( type == PreferenceType::Deprecated ),
+	m_bImmutable( type == PreferenceType::Immutable )
 {
 	m_Subscribers.Subscribe( this );
 }
@@ -81,14 +82,17 @@ void IPreference::ReadFrom( const XNode* pNode, bool bIsStatic )
 	if( pNode->GetAttrValue(m_sName, sVal) )
 	{
 		FromString( sVal );
-		m_bIsStatic = bIsStatic;
+		if (bIsStatic)
+			m_bDoNotWrite = true;
 	}
 }
 
 void IPreference::WriteTo( XNode* pNode ) const
 {
-	if( !m_bIsStatic )
-		pNode->AppendAttr( m_sName, ToString() );
+	if (m_bDoNotWrite)
+		return;
+
+	pNode->AppendAttr( m_sName, ToString() );
 }
 
 /* Load our value from the node, and make it the new default. */

src/Preference.h

@@ -8,11 +8,28 @@
 #include "RageUtil.h"
 class XNode;
 
+enum class PreferenceType
+{
+	// Allow reading and writing of the preference through Lua.
+	// This is the default behavior.
+	Mutable,
+
+	// Mark the preference as read-only i.e. don't allow setting of the 
+	// preference through Lua.
+	Immutable,
+
+	// The preference is deprecated.
+	// This deprecated flag will not be written to the Preferences file.
+	// If this preference was deprecated in favor of a new one, see
+	// TranslateDeprecatedFlags() to see the what it was deprecated in favor of.
+	Deprecated,
+};
+
 struct lua_State;
 class IPreference
 {
 public:
-	IPreference( const RString& sName );
+	IPreference( const RString& sName, PreferenceType type );
 	virtual ~IPreference();
 	void ReadFrom( const XNode* pNode, bool bIsStatic );
 	void WriteTo( XNode* pNode ) const;
@@ -36,10 +53,11 @@ public:
 	static void ReadAllDefaultsFromNode( const XNode* pNode );
 
 	RString GetName() { return m_sName; }
-	void SetStatic( bool b ) { m_bIsStatic = b; }
+	bool IsImmutable() { return m_bImmutable; }
 private:
 	RString	m_sName;
-	bool m_bIsStatic;	// loaded from Static.ini?  If so, don't write to Preferences.ini
+	bool m_bDoNotWrite;
+	bool m_bImmutable;
 };
 
 void BroadcastPreferenceChanged( const RString& sPreferenceName );
@@ -48,8 +66,8 @@ template <class T>
 class Preference : public IPreference
 {
 public:
-	Preference( const RString& sName, const T& defaultValue, void (pfnValidate)(T& val) = nullptr ):
-		IPreference( sName ),
+	Preference( const RString& sName, const T& defaultValue, void (pfnValidate)(T& val) = nullptr, PreferenceType type = PreferenceType::Mutable ):
+		IPreference( sName, type ),
 		m_currentValue( defaultValue ),
 		m_defaultValue( defaultValue ),
 		m_pfnValidate( pfnValidate )
@@ -131,14 +149,14 @@ public:
 	typedef Preference<T> PreferenceT;
 	vector<PreferenceT*> m_v;
 	
-	Preference1D( void pfn(size_t i, RString &sNameOut, T &defaultValueOut ), size_t N )
+	Preference1D( void pfn(size_t i, RString &sNameOut, T &defaultValueOut ), size_t N, PreferenceType type = PreferenceType::Mutable )
 	{
 		for( size_t i=0; i<N; ++i )
 		{
 			RString sName;
 			T defaultValue;
 			pfn( i, sName, defaultValue );
-			m_v.push_back( new Preference<T>(sName, defaultValue) );
+			m_v.push_back( new Preference<T>(sName, defaultValue, nullptr, type) );
 		}
 	}
 

src/PrefsManager.cpp

@@ -264,9 +264,9 @@ PrefsManager::PrefsManager() :
 	m_CourseSortOrder		( "CourseSortOrder",			COURSE_SORT_SONGS ),
 	m_bSubSortByNumSteps		( "SubSortByNumSteps",			false ),
 	m_GetRankingName		( "GetRankingName",			RANKING_ON ),
-	m_sAdditionalSongFolders	( "AdditionalSongFolders",		"" ),
-	m_sAdditionalCourseFolders	( "AdditionalCourseFolders",		"" ),
-	m_sAdditionalFolders		( "AdditionalFolders",			"" ),
+	m_sAdditionalSongFolders	( "AdditionalSongFolders",		"", nullptr, PreferenceType::Immutable ),
+	m_sAdditionalCourseFolders	( "AdditionalCourseFolders",		"", nullptr, PreferenceType::Immutable ),
+	m_sAdditionalFolders		( "AdditionalFolders",			"", nullptr, PreferenceType::Immutable ),
 	m_sDefaultTheme			( "DefaultTheme",			"default" ),
 	m_sLastSeenVideoDriver		( "LastSeenVideoDriver",		"" ),
 	m_sVideoRenderers		( "VideoRenderers",			"" ),	// StepMania.cpp sets these on first run:
@@ -574,6 +574,11 @@ public:
 			LuaHelpers::ReportScriptErrorFmt( "SetPreference: unknown preference \"%s\"", sName.c_str() );
 			COMMON_RETURN_SELF;
 		}
+		else if (pPref->IsImmutable())
+		{
+			LuaHelpers::ReportScriptErrorFmt( "SetPreference: preference \"%s\" is immutable", sName.c_str() );
+			COMMON_RETURN_SELF;
+		}
 
 		lua_pushvalue( L, 2 );
 		pPref->SetFromStack( L );
@@ -589,6 +594,11 @@ public:
 			LuaHelpers::ReportScriptErrorFmt( "SetPreferenceToDefault: unknown preference \"%s\"", sName.c_str() );
 			COMMON_RETURN_SELF;
 		}
+		else if (pPref->IsImmutable())
+		{
+			LuaHelpers::ReportScriptErrorFmt( "SetPreference: preference \"%s\" is immutable", sName.c_str() );
+			COMMON_RETURN_SELF;
+		}
 
 		pPref->LoadDefault();
 		LOG->Trace( "Restored preference \"%s\" to default \"%s\"", sName.c_str(), pPref->ToString().c_str() );

src/arch/MemoryCard/MemoryCardDriver.cpp

@@ -22,7 +22,7 @@ XToString(MemoryCardDriverType);
 StringToX(MemoryCardDriverType);
 LuaXType(MemoryCardDriverType);
 
-Preference<MemoryCardDriverType> g_MemoryCardDriver("MemoryCardDriver", MemoryCardDriverType_Usb);
+Preference<MemoryCardDriverType> g_MemoryCardDriver("MemoryCardDriver", MemoryCardDriverType_Usb, nullptr, PreferenceType::Immutable);
 
 bool UsbStorageDevice::operator==(const UsbStorageDevice& other) const
 {