//
// trampoline must be static, and someone else needs to keep a ref to it
//
public unsafe void SetupBlock(Delegate trampoline, Delegate userDelegate)
{
isa = block_class;
invoke = Marshal.GetFunctionPointerForDelegate(trampoline);
local_handle = (IntPtr)GCHandle.Alloc(userDelegate);
global_handle = IntPtr.Zero;
flags = BlockFlags.BLOCK_HAS_COPY_DISPOSE | BlockFlags.BLOCK_HAS_SIGNATURE;
/* FIXME: support stret blocks */
// we allocate one big block of memory, the first part is the BlockDescriptor,
// the second part is the signature string (no need to allocate a second time
// for the signature if we can avoid it). One descriptor is allocated for every
// Block; this is potentially something the static registrar can fix, since it
// should know every possible trampoline signature.
var signature = Runtime.ComputeSignature(trampoline.Method);
var bytes = System.Text.Encoding.UTF8.GetBytes(signature);
var desclen = sizeof(XamarinBlockDescriptor) + bytes.Length + 1 /* null character */;
var descptr = Marshal.AllocHGlobal(desclen);
block_descriptor = descptr;
var xblock_descriptor = (XamarinBlockDescriptor *)block_descriptor;
xblock_descriptor->descriptor = *(BlockDescriptor *)xamarin_get_block_descriptor();
xblock_descriptor->descriptor.signature = descptr + sizeof(BlockDescriptor) + 4 /* signature_length */;
xblock_descriptor->xamarin_size = desclen;
Marshal.Copy(bytes, 0, xblock_descriptor->descriptor.signature, bytes.Length);
Marshal.WriteByte(xblock_descriptor->descriptor.signature + bytes.Length, 0); // null terminate string
}
//
// trampoline must be static, and someone else needs to keep a ref to it
//
public unsafe void SetupBlock(Delegate trampoline, Delegate userDelegate)
{
isa = block_class;
invoke = Marshal.GetFunctionPointerForDelegate(trampoline);
local_handle = (IntPtr)GCHandle.Alloc(userDelegate);
global_handle = IntPtr.Zero;
flags = BlockFlags.BLOCK_HAS_COPY_DISPOSE | BlockFlags.BLOCK_HAS_SIGNATURE;
/* FIXME: support stret blocks */
// We need to get the signature of the target method, so that we can compute
// the ObjC signature correctly (the generated method that's actually
// invoked by native code does not have enough type information to compute
// the correct signature).
// This attribute might not exist for third-party libraries created
// with earlier versions of Xamarin.iOS, so make sure to cope with
// the attribute not being available.
var userDelegateType = trampoline.GetType().GetCustomAttribute <UserDelegateTypeAttribute> ()?.UserDelegateType;
bool blockSignature;
MethodInfo userMethod;
if (userDelegateType != null)
{
userMethod = userDelegateType.GetMethod("Invoke");
blockSignature = true;
}
else
{
userMethod = trampoline.Method;
blockSignature = false;
}
// we allocate one big block of memory, the first part is the BlockDescriptor,
// the second part is the signature string (no need to allocate a second time
// for the signature if we can avoid it). One descriptor is allocated for every
// Block; this is potentially something the static registrar can fix, since it
// should know every possible trampoline signature.
var signature = Runtime.ComputeSignature(userMethod, blockSignature);
var bytes = System.Text.Encoding.UTF8.GetBytes(signature);
var desclen = sizeof(XamarinBlockDescriptor) + bytes.Length + 1 /* null character */;
var descptr = Marshal.AllocHGlobal(desclen);
block_descriptor = descptr;
var xblock_descriptor = (XamarinBlockDescriptor *)block_descriptor;
xblock_descriptor->descriptor = *(BlockDescriptor *)xamarin_get_block_descriptor();
xblock_descriptor->descriptor.signature = descptr + sizeof(BlockDescriptor) + 4 /* signature_length */;
xblock_descriptor->ref_count = 1;
Marshal.Copy(bytes, 0, xblock_descriptor->descriptor.signature, bytes.Length);
Marshal.WriteByte(xblock_descriptor->descriptor.signature + bytes.Length, 0); // null terminate string
}
