On Tue, 27 Apr 2021 19:31:40 GMT, Roger Riggs <rri...@openjdk.org> wrote:
>> Please consider this request to modify `Reader.read(CharBuffer)` to check
>> whether the buffer is read-only before reading any characters from the
>> character stream. This can happen now if the buffer is read-only. Character
>> are first read thereby advancing the stream before an attempt is made to put
>> them in the `CharBuffer` thus incorrectly advancing the stream position.
>
> src/java.base/share/classes/java/io/Reader.java line 202:
>
>> 200: if (target.isReadOnly())
>> 201: throw new ReadOnlyBufferException();
>> 202: int len = target.remaining();
>
> It seems like the other branch of the if should also check for read-only and
> throw.
> Or can the target not have an array if it is readonly.
> It might return -1 for a readonly target if the source was used up. The
> always throw.
>
> Moving the `if (target.isReadOnly())` to the line 188: would be unambiguous.
It can't have an array if it is read-only.
Returns:
true if, and only if, this buffer is backed by an array and is not read-only
https://docs.oracle.com/en/java/javase/16/docs/api/java.base/java/nio/CharBuffer.html#hasArray()
> test/jdk/java/io/Reader/ReadIntoReadOnlyBuffer.java line 52:
>
>> 50: try {
>> 51: r.read(b);
>> 52: throw new RuntimeException();
>
> A helpful message would make it clearer what failed, when/if it fails.
Agreed.
-------------
PR: https://git.openjdk.java.net/jdk/pull/3725
