RFR: 8245194: Unix domain socket channel implementation [v13]

[Erik Joelsson]

On Fri, 2 Oct 2020 11:28:49 GMT, Michael McMahon <michaelm at openjdk.org> wrote:

>> 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.
>>> 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.
>>>
>>>
>>>
>>>
>>>
>>>
>
> Michael McMahon has updated the pull request incrementally with one additional commit since the last revision:
> 
>   unixdomainchannels: error in the last commit in make/modules/java.base/Copy.gmk

make/modules/java.base/Copy.gmk line 190:

> 188: NET_PROPERTIES_SRC +=
> $(TOPDIR)/src/java.base/$(OPENJDK_TARGET_OS_TYPE)/conf/net.properties.$(OPENJDK_TARGET_OS_TYPE) 189:
> 190: NET_PROPERTIES_SRC_LIST := $(NET_PROPERTIES_SRC)

This variable seems unnecessary as it's just a copy of NET_PROPERTIES_SRC. I would suggest just adding an S for plural
to the original variable.

make/modules/java.base/Copy.gmk line 195:

> 193: 	$(call MakeTargetDir)
> 194: 	$(RM) $@ $@.tmp
> 195: 	$(foreach f,$(NET_PROPERTIES_SRC_LIST),$(CAT) $(f) >> $@.tmp;)

This can be simplified. Cat takes multiple files as input, so no need for 'foreach'. Also no need to go via a temp
file. We have make configured to delete targets if a recipe fails, so the tmp dance isn't needed. (I know we still have
this pattern all over the place, but we are trying to quit the practice)

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