RFR: 8351339: WebSocket::sendBinary assume that user supplied buffers are BIG_ENDIAN [v5]

[Volkan Yazici]

On Sun, 23 Mar 2025 08:50:30 GMT, Chen Liang <liach at openjdk.org> wrote:

>> src/java.net.http/share/classes/jdk/internal/net/http/websocket/Frame.java line 147:
>> 
>>> 145:          * Positions the {@link #offset} at 0, which is needed for vectorized masking, by masking necessary amount of bytes.
>>> 146:          */
>>> 147:         private void initVectorMask(ByteBuffer src, ByteBuffer dst) {
>> 
>> This method and `applyPlainMask` uses big-endian `maskBytes` which can be wrong if `dst` is not big endian. Should we just assert `dst` is big endian everywhere, as it seems to be the case?
>
> Opened intellij and verified the `dst` is always big endian coming from `ByteBuffer.allocate` in both client and server contexts.

@liach, `initVectorMask()` operates byte-by-byte, that is, nothing vectorized, and, hence, no endianness concerns there. `applyVectorMask()` chooses the mask with correct endianness based on the input:


assert src.order() == dst.order() : "vectorized masking is only allowed on matching byte orders";
long maskLong = ByteOrder.LITTLE_ENDIAN == src.order() ? maskLongLe : maskLongBe;


AFAICT, both methods are ready to perform vectorization independent of the input endianness – granted `src` and `dst` endiannesses match. Am I missing something?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24033#discussion_r2009822775