/// <summary>Converts an <c>NSException</c> into a managed exception and throws it.</summary>
/// <param name = "instance">The <a href ="http://developer.apple.com/documentation/Cocoa/Reference/Foundation/Classes/nsexception_Class/Reference/Reference.html">NSException</a>
/// pointer.</param>
/// <remarks>If the <c>NSException</c> wraps a managed exception then
/// <c>TargetInvocationException</c> is thrown instead with the inner exception
/// set to the original exception.</remarks>
public static void Raise(IntPtr instance)
{
NSObject obj = new NSObject(instance);
if (obj.isMemberOfClass(new Class("NSException")))
{
// See if the userInfo contains a .NET exception.
NSObject userInfo = (NSObject)obj.Call("userInfo");
if (userInfo != null && (IntPtr)userInfo != IntPtr.Zero)
{
IntPtr keyBuffer = Marshal.StringToHGlobalAuto(".NET exception");
NSObject key = (NSObject) new Class("NSString").Call("alloc").Call("initWithUTF8String:", keyBuffer);
key.autorelease();
Marshal.FreeHGlobal(keyBuffer);
NSObject data = (NSObject)userInfo.Call("objectForKey:", key);
if (data != null && !data.IsNil())
{
// If it does then get the serialized exception bytes,
IntPtr ptr = (IntPtr)data.Call("bytes");
uint bytes = (uint)data.Call("length");
// copy them into a managed buffer,
byte[] buffer = new byte[bytes];
Marshal.Copy(ptr, buffer, 0, (int)bytes);
// and raise the original exception.
using (MemoryStream stream = new MemoryStream(buffer))
{
BinaryFormatter formatter = new BinaryFormatter();
Exception e = (Exception)formatter.Deserialize(stream);
throw new TargetInvocationException("Exception has been thrown by the (managed) target of an Objective-C method call.", e); // yes TargetInvocationException sucks, but it preserves the original stack crawl...
}
}
}
}
throw new CocoaException(obj);
}
