RFR: 8320971: Use BufferedInputStream.buf directly when param of implTransferTo() is trusted [v2]

[Vladimir Sitnikov]

On Fri, 1 Dec 2023 14:05:37 GMT, Bernd <duke at openjdk.org> wrote:

>> Did you review if all Java.* streams are safe?
>> 
>> There are a few stream adapters in sun.nio.ch, which would benefit this optimization too, unfortunately they wrap the arrays with ByteBuffer.wrap, I guess that’s not safe, so the package can’t be allowed?
>
>> @ecki I've checked the streams in `java.*` and it looks like none of them modifies the incoming `byte[]`
> 
> i think modification is not the problem, the querstion is if they get exposed to user code. (but yes the readonly ByteBuffer wrapper looks like a good thing to use more).

@ecki , what do you think of using read-only `ByteBuffer` instead?

See https://github.com/openjdk/jdk/pull/16879#discussion_r1410416823

It looks like there might be `OutputStream extends WritableByteChannel`. Then we won't need to perform deep analysis.

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PR Comment: https://git.openjdk.org/jdk/pull/16879#issuecomment-1836180161