RFR: 8320971: Use BufferedInputStream.buf directly when param of implTransferTo() is trusted [v15]

[Markus KARG]

On Thu, 14 Dec 2023 08:47:03 GMT, Sergey Tsypanov <stsypanov at openjdk.org> wrote:

>> It looks like we can skip copying of `byte[]` in `BufferedInputStream.implTransferTo()` for `OutputStreams` residing in `java.io`.
>> 
>> See comment by @vlsi in https://github.com/openjdk/jdk/pull/10525/files#diff-e19c508d1bb6ee78697ecca66947c395adda0d9c49a85bf696e677ecbd977af1R612
>
> Sergey Tsypanov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8320971: Revert irrelevant changes

I know it is a bit disappointing to undo the nice changes you did just days ago, but to get this PR merged quickly it is best to follow Alan's proposal.

src/java.base/share/classes/java/io/BufferedInputStream.java line 677:

> 675:      * @see java.io.BufferedInputStream#implTransferTo(OutputStream)
> 676:      */
> 677:     private static boolean isTrusted(OutputStream os) {

Let's follow Alan's proposal and simply inline this. The solution is in sync with BAIS then, and we can merge it quickly.

test/jdk/java/io/BufferedInputStream/TransferToTrusted.java line 85:

> 83:     }
> 84: 
> 85:     private static void byteArrayOutputStream(BufferedInputStream bis, byte[] buf) throws IOException {

As we agreed that this PR shall only cover BIS, we can remove the additional classes' tests again.

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Changes requested by mkarg at github.com (no known OpenJDK username).

PR Review: https://git.openjdk.org/jdk/pull/16879#pullrequestreview-1785245773
PR Review Comment: https://git.openjdk.org/jdk/pull/16879#discussion_r1428872958
PR Review Comment: https://git.openjdk.org/jdk/pull/16879#discussion_r1428873231