RFR: 8245194: Unix domain socket channel implementation

[Michael McMahon]

Continuing this review as a PR on github with the comments below incorporated. I expect there will be a few more
iterations before integrating.

On 06/09/2020 19:47, Alan Bateman wrote:
> On 26/08/2020 15:24, Michael McMahon wrote:
>>
>> As I mentioned the other day, I wasn't able to use the suggested method on Windows which returns an absolute path. So,
>> I added a method to WindowsPath which returns the path in the expected UTF-8 encoding as a byte[]. Let me know what you
>> think of that.
>>
>> There is a fair bit of other refactoring and simplification done also. Next version is at:
>>
>> http://cr.openjdk.java.net/~michaelm/8245194/impl.webrev/webrev.9/
>>
> Adding a method to WindowsPath to encode the path using UTF-8 is okay but I don't think we should be caching it as the
> encoding for sun_path is an outlier on Windows. I'm also a bit dubious about encoding a relative path when the resolved
> path (before encoding) is > 247 chars. The documentation on the MS site isn't very completely and I think there are a
> number points that require clarification to fully understand how this will work with relative, directly relative and
> drive relative paths.
>

Maybe it would be better to just use the path returned from toString() and do the conversion to UTF-8 externally. That
would leave WindowsPath unchanged. I also changed the

> In the same area, the new PathUtil is a bit inconsistent with the existing provider code. One suggestion is to add a
> method to AbstractFileSystemProvider instead. That is the base class the platform providers and would be a better place
> to get the file path in bytes.
>

Okay, I gave the method a name that is specific to Unix domain sockets because this UTF-8 strangeness is not likely to
be useful by other components.

> One other comment on the changes to the file system provider it should be okay to change UnixUserPrinipals ad its
> fromUid and fromGid method to be public. This would mean that the patch shouldn't need to add UnixUserGroup (the main
> issue is that class is that it means we end up with two classes with static factory methods doing the same thing).

Okay, that does simplify it a bit.

Thanks,
Michael.

> -Alan.
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Commit messages:
 - unixdomainchannels: fixing compile error on Windows and Alan's review comment this morning
 - unixdomainchannels: initial commit from hg sandbox with changes from Alan's email 06/09/2020

Changes: https://git.openjdk.java.net/jdk/pull/52/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=52&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8245194
  Stats: 6960 lines in 87 files changed: 5902 ins; 763 del; 295 mod
  Patch: https://git.openjdk.java.net/jdk/pull/52.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/52/head:pull/52

PR: https://git.openjdk.java.net/jdk/pull/52