RFR: 8271186: Add UL option to replace newline char [v7]

[David Holmes]

On Wed, 25 Aug 2021 07:39:54 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

>> Most of UL entries would print log in one line, however some categories (e.g. `exceptions`) have multiline entries as following:
>> 
>> 
>> [0.157s][info][exceptions] Exception <a 'java/lang/NullPointerException'{0x000000008b918f70}: test>
>>  thrown in interpreter method <{method} {0x00007f8335000248} 'main' '([Ljava/lang/String;)V' in 'Test'>
>>  at bci 9 for thread 0x00007f8330017160 (main)
>> 
>> 
>> It is ease to parse with log shipper (Fluent Bit, Logstash, and more) if UL can print all logs in one line.
>> Famous log shippers support multiline logs of course, but its configuration tends to be complex, and also some input plugins (e.g. TCP on Fluent Bit) do not support multiline logs.
>> 
>> So I want to introduce new UL option `foldmultilines` to replace all of newline char (`\n`) in the log entry will be replaced to 2 chars `\\n`. In addition, all of backslashes (`\` in C) are also replaced to 2 chars `\\\`.
>> 
>> After this patch, we can get following logs with `foldmultilines=true`:
>> 
>> 
>> [0.166s][info][exceptions] Exception <a 'java/lang/NullPointerException'{0x000000008b918f70}: test>\n thrown in interpreter method <{method} {0x00007fbc81000248} 'main' '([Ljava/lang/String;)V' in 'Test'>\n at bci 9 for thread 0x00007fbc9c0171a0 (main)
>> 
>> 
>> I've also filed [CSR](https://bugs.openjdk.java.net/browse/JDK-8271188) for this issue, please review it.
>
> Yasumasa Suenaga has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update manpage of java

Seems okay now.

Thanks,
David

-------------

Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4885