public static bool TryGetFunction(
FieldInfo field,
Func <string, IntPtr> methodHandleFactory,
out Delegate @delegate)
{
if (field == null)
{
throw new ArgumentNullException(nameof(field));
}
if (methodHandleFactory == null)
{
throw new ArgumentNullException(nameof(methodHandleFactory));
}
LoadFunctionAttribute attribute = field.GetCustomAttribute <LoadFunctionAttribute>();
IntPtr methodHandle = methodHandleFactory.Invoke(attribute.EntryPoint);
if (methodHandle != IntPtr.Zero)
{
@delegate = Marshal.GetDelegateForFunctionPointer(methodHandle, field.FieldType);
return(true);
}
@delegate = null;
return(false);
}
public static bool TryGetFunction(
FieldInfo field,
Func <string, IntPtr> methodHandleFactory,
Expression <Func <object> > onFunctionCall,
out Delegate @delegate)
{
if (field == null)
{
throw new ArgumentNullException(nameof(field));
}
if (methodHandleFactory == null)
{
throw new ArgumentNullException(nameof(methodHandleFactory));
}
LoadFunctionAttribute attribute = field.GetCustomAttribute <LoadFunctionAttribute>();
IntPtr methodHandle = methodHandleFactory.Invoke(attribute.EntryPoint);
if (methodHandle == IntPtr.Zero && onFunctionCall != null)
{
@delegate = field.FieldType.GetEmptyDebugDelegate(onFunctionCall);
return(false);
}
else if (!attribute.DisableOnFunctionCall)
{
// TODO:
// @delegate = ptr.GetDebugDelegate(field.FieldType, onFunctionCall);
// return true;
}
@delegate = Marshal.GetDelegateForFunctionPointer(methodHandle, field.FieldType);
return(true);
}
/// <summary>
/// Loads all unmanaged functions of provided type and binding flags.
/// </summary>
/// <param name="type">The type</param>
/// <param name="methodHandleFactory">The function that retrieves the handle</param>
/// <returns>returns a collection of error string</returns>
public static ICollection <string> LoadFunctions(
this Type type,
Func <string, IntPtr> methodHandleFactory)
{
if (type == null)
{
throw new ArgumentNullException(nameof(type));
}
if (methodHandleFactory == null)
{
throw new ArgumentNullException(nameof(methodHandleFactory));
}
var errors = new List <string>();
IEnumerable <FieldInfo> fields = type
.GetFields(DefaultBindingFlags)
.Where(i => i.IsDefined(typeof(LoadFunctionAttribute)));
foreach (FieldInfo field in fields)
{
if (!UnmanagedHelper.TryGetFunction(field, methodHandleFactory, out Delegate @delegate))
{
LoadFunctionAttribute attribute = field.GetCustomAttribute <LoadFunctionAttribute>();
errors.Add($"Failed to load `{type.Name}` function `{attribute.EntryPoint}`.");
}
field.SetValue(null, @delegate);
}
return(errors);
}
