Unity - Scripting API:

public static function IsOpenForEdit(assetObject: Object): bool;

public static bool IsOpenForEdit(Object assetObject);

public static function IsOpenForEdit(assetOrMetaFilePath: string): bool;

public static bool IsOpenForEdit(string assetOrMetaFilePath);

public static function IsOpenForEdit(assetObject: Object, out message: string): bool;

public static bool IsOpenForEdit(Object assetObject, out string message);

public static function IsOpenForEdit(assetOrMetaFilePath: string, out message: string): bool;

public static bool IsOpenForEdit(string assetOrMetaFilePath, out string message);

Parameters

assetPath	Is the path to the asset on disk relative to project folder.
message	Used to give reason for not open.

bool True is the asset can be edited.

Use IsOpenForEdit to determine if the asset is open for edit by the version control.

Used to disable editor controls.