RFR: 8314569: (fs) Improve normalization of UnixPath for directories(fs) Improve normalization of UnixPath for input with trailing slashes [v2]

[Alan Bateman]

On Mon, 21 Aug 2023 10:50:47 GMT, Sergey Tsypanov <stsypanov at openjdk.org> wrote:

>> Sergey Tsypanov has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - Merge branch 'master' into unixpath-check-nn
>>  - Further improvement
>>  - Improve UnixPath normalization
>
> Updated the PR. Checked cases for normal path (requires no normalization) and root:
> 
> @BenchmarkMode(Mode.AverageTime)
> @OutputTimeUnit(TimeUnit.NANOSECONDS)
> @Warmup(time = 2, iterations = 5)
> @Measurement(time = 2, iterations = 5)
> @Fork(value = 4, jvmArgs = "-Xmx1g")
> public class FileToPathBenchmark {
> 
>     @Benchmark
>     public Path toDirectoryPath(Data data) {
>         return FileSystems.getDefault().getPath(data.directoryPath);
>     }
> 
> 
>     @Benchmark
>     public Path toDirectoryPathDoubleSlash(Data data) {
>         return FileSystems.getDefault().getPath(data.directoryPathWithDoubleSlash);
>     }
> 
>     @Benchmark
>     public Path toNormalPath(Data data) {
>         return FileSystems.getDefault().getPath(data.normalPath);
>     }
> 
>     @Benchmark
>     public Path toRootPath(Data data) {
>         return FileSystems.getDefault().getPath(data.rootPath);
>     }
> 
>     @State(Scope.Thread)
>     public static class Data {
>         private final String rootPath = "/";
>         private final String normalPath = "/tmp/tmp/tmp";
>         private final String directoryPath = "/tmp/tmp/tmp/";
>         private final String directoryPathWithDoubleSlash = "/tmp//tmp/tmp/";
>     }
> }
> 
> Results:
> 
> baseline
> 
> Benchmark                                                           Mode  Cnt     Score     Error   Units
> FileToPathBenchmark.toDirectoryPath                                 avgt   20    44.993 ±   1.676   ns/op
> FileToPathBenchmark.toDirectoryPath:·gc.alloc.rate                  avgt   20  3732.628 ± 137.446  MB/sec
> FileToPathBenchmark.toDirectoryPath:·gc.alloc.rate.norm             avgt   20   176.000 ±   0.001    B/op
> FileToPathBenchmark.toDirectoryPath:·gc.count                       avgt   20   234.000            counts
> FileToPathBenchmark.toDirectoryPath:·gc.time                        avgt   20  1129.000                ms
> FileToPathBenchmark.toDirectoryPathDoubleSlash                      avgt   20    58.963 ±   1.737   ns/op
> FileToPathBenchmark.toDirectoryPathDoubleSlash:·gc.alloc.rate       avgt   20  2717.169 ±  78.664  MB/sec
> FileToPathBenchmark.toDirectoryPathDoubleSlash:·gc.alloc.rate.norm  avgt   20   168.000 ±   0.001    B/op
> FileToPathBenchmark.toDirectoryPathDoubleSlash:·gc.count            avgt   20   190.000            counts
> FileToPathBenchmark.toDirectoryPathDoubleSlash:·gc.time             avgt   20   755.000                ms
> FileToPathBenchmark.toNormalPath                                    avgt   20    14.017 ±   0.367   ns/op
> FileToPathBenchmark.toNormalPath:·gc.alloc....

@stsypanov The title on the PR is currently:

"(fs) Improve normalization of UnixPath for directories(fs) Improve normalization of UnixPath for input with trailing slashes #15342"

Something got fat fingered somewhere. Can you fix it to match the JBS issue  "(fs) Improve normalization of UnixPath for input with trailing slashes" and then we can sponsor?

-------------

PR Comment: https://git.openjdk.org/jdk/pull/15342#issuecomment-1696931696