RFR: 8286160: (fs) Files.exists returns unexpected results with C:\pagefile.sys because it's not readable

[Brian Burkhalter]

On Tue, 7 Jun 2022 09:29:37 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> If in `WindosFileSystemProvider.checkAccess(Path obj, AccessMode... modes)` the sub-test `checkReadAccess(WindowsPath)` fails and no modes are specified, then try to determine file existence by reading the file's attributes.
>
> src/java.base/windows/classes/sun/nio/fs/WindowsFileSystemProvider.java line 395:
> 
>> 393:                 }
>> 394:                 throw ioe;
>> 395:             }
> 
> Testing the existence of a file is performance issue in some usages and would be interesting to see if this would be a bit better.
> 
> 
>         // check file exists only
>         if (!r && !w && !x) {
>             file.checkRead();
>             try {
>                 WindowsFileAttributes.get(file, true);
>                 return;
>             } catch (WindowsException e) {
>                 exc.rethrowAsIOException(file);
>             }
>         }

That was actually my first draft version. What happened to `checkReadAccess()` here?

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PR: https://git.openjdk.java.net/jdk/pull/9045