[OpenJDK 2D-Dev] RFR: 8254825: Monitoring available clipboard formats should be done via new Windows APIs

[Sergey Bylokhov]

On Sun, 11 Oct 2020 19:58:20 GMT, Daniel Kamil Kozar <github.com+127875+xavery at openjdk.org> wrote:

> This change replaces the usage of SetClipboardViewer with Add/RemoveClipboardFormatListener, introduced in Windows Vista. This makes OpenJDK immune to external applications failing to process clipboard messages properly.
> I have put this proposal forward in the [mailing list](https://mail.openjdk.java.net/pipermail/awt-dev/2020-July/015990.html), which was tentatively accepted by Mr. Sergey Bylokhov.
> 
> The deficiencies of the old APIs are well known and might result in some subscribed applications not receiving notifications from the operating system, as they rely on all the applications in the current clipboard chain processing clipboard messages properly. Porting the code to use the new APIs not only makes OpenJDK immune to these issues, but also results in slightly less code needed to support clipboard-related functionality.
> 
> As this is a change that's very platform-specific, I don't think providing a unit test is practical, as it would also require providing a native application that runs alongside the test and deliberately breaks the keyboard chain, resulting in OpenJDK not being able to receive clipboard format change notifications. This is a bug/limitation of the old Windows API, not OpenJDK itself. Anyhow, the already existing ClipboardInterVMTest passes, which shows that already existing functionality is not impacted by this change.
> 
> I have prepared a proof-of-concept test which illustrates the deficiencies of the old API, however it is not integrated with the test suite, as it requires compiling a native WinAPI application. I will gladly share the source if needed.

Please update the second date in the header of the changed files to 2020.

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Changes requested by serb (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/594