RFR: 8360025: (se) Convert kqueue Selector Implementation to use FFM APIs

[Alan Bateman]

On Wed, 15 Oct 2025 08:29:47 GMT, Andrey Turbanov <aturbanov at openjdk.org> wrote:

>> This PR was originally part of #25546, though that PR has been split in 2, the first chunk was https://github.com/openjdk/jdk/pull/27590.
>> 
>> This PR aims to convert KQueue to use FFM apis, the first PR in this area added all the jextract generated code needed, while this PR modifies some of the jextract code and then uses it with Kqueue.
>> 
>> A brief rundown of the changes:
>> - The files `errno_h$shared.java` , `kqueue_h$shared.java`, `timespec_h$shared.java` and `timespec_h.java` have all been deleted. This is because they all contained shared elements that could be moved into the Utility file `FFMUtils.java`
>> - `Kqueue.c` has been deleted, and all native methods in the other `KQueue` files have been replaced with references to the generated files kevent and kqueue. This is the bulk of the changes
>> - Both the `Kqueue()` and `Kevent()` methods in `kqueue_h.java`  were modified to use adapted method handles that will return the errno value
>
> src/java.base/macosx/classes/sun/nio/ch/KQueue.java line 134:
> 
>> 132:     }
>> 133: 
>> 134:     static public int poll(int kqfd, MemorySegment pollAddress, int nevents, long timeout) {
> 
> Let's use blessed modifiers order
> Suggestion:
> 
>     public static int poll(int kqfd, MemorySegment pollAddress, int nevents, long timeout) {

I assume "public" was added by mistake, this is not a public class, instead it's means to be a simpler wrapper on kqueue for the Selector, Port and Poller implementations in the macOS specific sun.nio.ch.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27796#discussion_r2431679711