RFR: 8264400: (fs) WindowsFileStore equality depends on how the FileStore was constructed [v3]

[Alan Bateman]

On Thu, 8 Apr 2021 16:15:23 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Please consider this change to make `sun.nio.fs.WindowsFileStore.equals()` return `true` if the root strings of the two objects are equal under case insensitive comparison, and the two `WindowsFileStore`s have the same volume information.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8264400: Remove hasHashCode and race on hashCode == 0

src/java.base/windows/classes/sun/nio/fs/WindowsFileStore.java line 234:

> 232:             return supportsFileAttributeView(FileOwnerAttributeView.class);
> 233:         if (name.equals("user"))
> 234:             return supportsFileAttributeView(UserDefinedFileAttributeView.class); return false;

Can you revert this change, it's not part of the fix and it makes this method harder to maintain.

src/java.base/windows/classes/sun/nio/fs/WindowsFileStore.java line 241:

> 239:         if (ob == this)
> 240:             return true;
> 241:         if (!(ob instanceof WindowsFileStore))

We can change this to
if (ob instanced WindowsFileStore other) { ... } and it will avoid the cast.

src/java.base/windows/classes/sun/nio/fs/WindowsFileStore.java line 254:

> 252:     public int hashCode() {
> 253:         if (hashCode == 0) { // Don't care about race
> 254:             hashCode = volType == DRIVE_FIXED ?

minor nit but would be a bit easier to read if changed to 
hashCode = (volType == DRIVE_FIXED) ? ...

test/jdk/java/nio/file/FileStore/Basic.java line 89:

> 87:             FileSystem fs = FileSystems.getDefault();
> 88:             FileStore upper = Files.getFileStore(fs.getPath("C:\\"));
> 89:             FileStore lower = Files.getFileStore(fs.getPath("c:\\"));

Path.of("c:\") can be used if you want.

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PR: https://git.openjdk.java.net/jdk/pull/3279