RFR: 8294293: Remove unused _width and _newlines field in outputStream

[David Holmes]

On Fri, 23 Sep 2022 15:59:39 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

> 1. `_width` is unused so I deleted it
> 2. `_newlines` was used in one place, and only to check if any new lines had been seen. I removed `_newlines` and instead used `update_position`'s unused return value to indicate whether any newlines has been seen. This required expanding the call of `xmlTextStream::write` in `defaultStream`.
> 
> This removes some cruft from `outputStream` and saves us 8 bytes on the size of `outputStream`.
> 
> I also noted that `_position` isn't number of chars into a line, but rather a "visual position". It's a bit surprising, which is why I added this comment. This can be seen in the `\t` case in `update_position`.

Generally seems okay but a couple of queries.

Thanks.

src/hotspot/share/utilities/ostream.cpp line 904:

> 902:   if (has_log_file()) {
> 903:     int nl0 = _newlines;
> 904:     xmlTextStream::write(s, len);

xmlTextStream::write seems to be unused after this change.

src/hotspot/share/utilities/ostream.hpp line 32:

> 30: #include "utilities/globalDefinitions.hpp"
> 31: #include "utilities/macros.hpp"
> 32: #include <cstdint>

This std header doesn't seem to be used anywhere else in hotspot code - why do we need it here?

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PR: https://git.openjdk.org/jdk/pull/10411