[8u] RFR 8254631: Better support ALPN byte wire values in SunJSSE

[Martin Balao]

Hi Severin,

Thanks for having a look at this.

On 4/26/21 8:39 AM, Severin Gehwolf wrote:
>>  * AlpnGreaseTest.java uses a java.util.Arrays public API not available
>> in 8u (introduced by JDK-8033148 [2]).
>>   * Fixed creating copies of the arrays to compare.
> 
>   89             System.arraycopy(bytes, i, a1, 0, greaseBytes.length);
>   90             System.arraycopy(greaseBytes, 0, a2, 0, greaseBytes.length);
>   91             if (Arrays.equals(a1, a2)) {
> 
> I don't think we'd need to copy greaseBytes for this array comparison,
> do we? Can't we use 'Arrays.equals(a1, greaseBytes)'?
> 
> Better yet, don't do a copy at all and just do a simple search using a
> ByteBuffer like this:
> https://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8254631.test-fix.patch

Yes, I didn't put much thinking into this but you are right: performance
can be improved. In that regard, looks to me that wrapping with a
ByteBuffer may not be necessary when we consider the precondition that,
inside the outer loop [1], 'bytes' array will be equal or greater than
'grease' array.

Please have a look at this proposal:

 *
http://cr.openjdk.java.net/~mbalao/webrevs/8254631/8254631.webrev.jdk8u.jdk.01/

Kind regards,
Martin.-

--
[1] - 86         for (int i = 0; i < bytes.length - greaseBytes.length;
i++) {