RFR: 8264774: Implementation of Foreign Function and Memory API (Incubator)
chegar at openjdk.java.net
Wed Apr 28 08:22:52 UTC 2021
On Tue, 27 Apr 2021 18:40:24 GMT, Alan Bateman <alanb at openjdk.org> wrote:
>> This PR contains the API and implementation changes for JEP-412 . A more detailed description of such changes, to avoid repetitions during the review process, is included as a separate comment.
>>  - https://openjdk.java.net/jeps/412
> src/java.base/share/classes/sun/nio/ch/IOUtil.java line 466:
>> 464: }
>> 466: private static final JavaNioAccess NIO_ACCESS = SharedSecrets.getJavaNioAccess();
> It might be cleaner to move to acquire/release methods to their own supporting class as it's not really IOUtil.
I went back and forth on this a number of times already. I think where we landed is a reasonable place, given the current shape of the code.
Scope is a private property of Buffer, and as such should be consulted anywhere where a buffer's address is being accessed. In fact, a prior prototype would not allow access to the underlying address value without the caller passing a valid handle for the buffer view's scope. It's hard to find the sweet-spot here between code reuse and safety, but the high-order bit is that the code accessing the address is auditable and testable to avoid accessing memory unsafely. Maybe there is a better alternative implementation code structure (at the cost of some duplication), but it is not obvious to me what that is (and I have given it some thought). Suggestions welcome.
Note, there is a little more follow-on work to be done in this area, if we are to expand support to other non-TCP channel implementations. Maybe investigation into possible code refactorings could be done as part of that?
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