/// <summary>
/// If the visual is on channel, its reference count is increased.
/// Otherwise, a new resource is created on that channel.
/// </summary>
internal bool CreateOrAddRefOnChannel(
object instance,
DUCE.Channel channel,
DUCE.ResourceType resourceType)
{
int index = Find(channel);
int count = Count;
if (index == PROXY_NOT_FOUND)
{
//
// This is the case where we have to create a new resource.
//
if (_head.Channel == null)
{
//
// We're adding the first proxy.
//
// Before: [empty]
// After insert: [ head]
//
Debug.Assert(count == 0);
_head.Channel = channel;
_head.Flags = VisualProxyFlags.None;
channel.CreateOrAddRefOnChannel(
instance,
ref _head.Handle,
resourceType);
}
else
{
if (_tail == null)
{
//
// We're adding the second proxy.
//
// Before: [head]
// After resize: [head] [ empty] [empty]
// After insert: [head] [tail 0] [empty]
// ----------------
Debug.Assert(count == 1);
_tail = new Proxy[2];
}
else if (count > _tail.Length)
{
//
// Increase the tail size by 2.
//
// Before: [head] [tail 0] ... [tail c-2]
// After resize: [head] [tail 0] ... [tail c-2] [ empty] [empty]
// After insert: [head] [tail 0] ... [tail c-3] [tail c-2] [empty]
// ------------------------------------------
//
ResizeTail(2);
}
//
// Now that we have a tail, fill in the first free element.
//
Proxy proxy;
proxy.Channel = channel;
proxy.Flags = VisualProxyFlags.None;
proxy.Handle = DUCE.ResourceHandle.Null;
channel.CreateOrAddRefOnChannel(
instance,
ref proxy.Handle,
resourceType);
_tail[count - 1] = proxy;
}
return /* created */ true;
}
else if (index == PROXY_STORED_INLINE)
{
//
// We simply need to increase the reference count on head...
//
channel.CreateOrAddRefOnChannel(
instance,
ref _head.Handle,
resourceType);
}
else
{
//
// Increase the reference count on one of the tail proxies...
//
channel.CreateOrAddRefOnChannel(
instance,
ref _tail[index].Handle,
resourceType);
}
return /* not created */ false;
}