Add new api's to IObjectReference to safely use the underlying pointer. #1474
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jlaanstra
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| if (__return_value__ != IntPtr.Zero) | ||
| { | ||
| (*(global::WinRT.Interop.IUnknownVftbl**)__return_value__)->Release(__return_value__); | ||
| MarshalInspectable<object>.DisposeAbi(__return_value__); |
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Why MarshalInspectable<object> rather than just the Release call like before? It's more efficient.
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This is pretty much how this is done everywhere else. I can revert but consistency is nice.
| @@ -303,13 +314,13 @@ internal abstract class State : IDisposable | |||
| public System.Delegate del; | |||
| public System.Delegate eventInvoke; | |||
| private bool disposedValue; | |||
| private readonly IntPtr obj; | |||
| private readonly IObjectReference obj; | |||
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This is potentially a semantics change, as the event source state wasn't previously keeping the RCW instance alive (unless indirectly captured by the wrapped delegate), but only the pointer to the native object. Are we sure changing this is not going to introduce some unwanted side effects and/or potentially any leaks anywhere?
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It's possible that this case isn't right, but without it how can we guarantee that the IntPtr is valid? I'll check it once the other changes are done.
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I don't think we need to. Looking at the state type, the pointer is only being used as object identity (as in, as a key in the internal cache). But it's never actually used to access the native COM object and interact with it. So even if the object did go away, this code would still be fine. There's some delicate GC stuff going on between the event source and the event state and I'm inclined to think the object reference wasn't being rooted by the state on purpose 😅
Add a pattern similar to SafeHandle to safely access the pointer of an ObjectReference.
Depends on #1458