RFR: 8343342: java/io/File/GetXSpace.java fails on Windows with CD-ROM drive [v6]

[Brian Burkhalter]

On Mon, 9 Dec 2024 10:55:13 GMT, Taizo Kurashige <duke at openjdk.org> wrote:

>> To resolve java/io/File/GetXSpace.java failure, I fix libGetXSpace.c to use  Cygwin’s `df` to get the size for comparison if the test target drive is a CD-ROM drive.
>> 
>> As described in JDK-8343342, GetDiskSpaceInformationW can't get information about the size of the CD-ROM drive. 
>> GetDiskFreeSpaceExW can also get information about the size of the CD-ROM drive. However, because GetDiskFreeSpaceExW is called by the File.get-X-Space methods, it seems more reasonable to compare the size got by other way than GetDiskFreeSpaceExW as a test. For this reason, I use Cygwin's `df`.
>> In JDK-8298619, GetDiskSpaceInformationW was adopted instead of `df` because the size got by File.get-X-Space methods may not match the size got by `df` when per-user quotas are used. I don't think this problem applies to CD-ROM  drive, so I think we can use Cygwin's `df` for CD-ROM drive.
>> 
>> After fix, I ran a test on Windows Server 2019 where drive C is a normal local disk, drive D is an unmounted iso CD-ROM  drive, and drive F is an iso mounted CD-ROM drive and confirmed that it passes.
>> 
>> I think this fix may also resolves the similar failure reported at https://github.com/openjdk/jdk/pull/12397#issuecomment-1705164515.
>> 
>> Thanks
>
> Taizo Kurashige has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add ifdef WINDOWS

test/jdk/java/io/File/libGetXSpace.c line 165:

> 163: #ifdef WINDOWS
> 164: JNIEXPORT jboolean JNICALL
> 165: Java_GetXSpace_isCDDrive

The native `GetXSpace` method needs to be defined on all platforms, otherwise we get the following on Unix:

java.lang.UnsatisfiedLinkError: 'boolean GetXSpace.isCDDrive(java.lang.String)'
	at GetXSpace.isCDDrive(Native Method)
	at GetXSpace$Space.<init>(GetXSpace.java:109)
	at GetXSpace.testVolumes(GetXSpace.java:353)
	at GetXSpace.main(GetXSpace.java:384)

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PR Review Comment: https://git.openjdk.org/jdk/pull/21799#discussion_r1880724106