bt90 05cc6b0f43 chore(fs): speed up case normalization (#10013) ...

### Purpose

Resurrecting https://github.com/syncthing/syncthing/pull/9365

### Testing

Current benchmark results:

```
goos: linux
goarch: amd64
pkg: github.com/syncthing/syncthing/lib/fs
cpu: AMD EPYC 7763 64-Core Processor                
                                           │  ../old.txt  │             ../new.txt              │
                                           │    sec/op    │   sec/op     vs base                │
UnicodeLowercase/ASCII_lowercase-4            43.68n ± 4%   12.19n ± 1%  -72.09% (p=0.000 n=10)
UnicodeLowercase/ASCII_mixedcase_start-4     200.65n ± 2%   59.49n ± 3%  -70.35% (p=0.000 n=10)
UnicodeLowercase/ASCII_mixedcase_end-4        95.50n ± 2%   59.10n ± 2%  -38.12% (p=0.000 n=10)
UnicodeLowercase/Latin1_lowercase-4           122.5n ± 1%   131.4n ± 1%   +7.27% (p=0.000 n=10)
UnicodeLowercase/Latin1_mixedcase_start-4     339.9n ± 2%   309.2n ± 1%   -9.05% (p=0.000 n=10)
UnicodeLowercase/Latin1_mixedcase_end-4       183.6n ± 2%   174.3n ± 1%   -5.04% (p=0.000 n=10)
UnicodeLowercase/Unicode_lowercase-4          456.6n ± 1%   440.5n ± 1%   -3.53% (p=0.000 n=10)
UnicodeLowercase/Unicode_mixedcase_start-4    625.9n ± 1%   595.6n ± 1%   -4.83% (p=0.000 n=10)
UnicodeLowercase/Unicode_mixedcase_end-4      516.2n ± 1%   495.5n ± 1%   -4.02% (p=0.000 n=10)
geomean                                       214.1n        150.4n       -29.72%

                                           │  ../old.txt  │             ../new.txt              │
                                           │     B/op     │    B/op     vs base                 │
UnicodeLowercase/ASCII_lowercase-4           0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/ASCII_mixedcase_start-4     24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/ASCII_mixedcase_end-4       24.00 ± 0%     24.00 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_lowercase-4          0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_mixedcase_start-4    32.00 ± 0%     32.00 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_mixedcase_end-4      32.00 ± 0%     32.00 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_lowercase-4         0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_mixedcase_start-4   48.00 ± 0%     48.00 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_mixedcase_end-4     48.00 ± 0%     48.00 ± 0%       ~ (p=1.000 n=10) ¹
geomean                                                 ²               +0.00%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                                           │  ../old.txt  │             ../new.txt              │
                                           │  allocs/op   │ allocs/op   vs base                 │
UnicodeLowercase/ASCII_lowercase-4           0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/ASCII_mixedcase_start-4     1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/ASCII_mixedcase_end-4       1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_lowercase-4          0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_mixedcase_start-4    1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Latin1_mixedcase_end-4      1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_lowercase-4         0.000 ± 0%     0.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_mixedcase_start-4   1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
UnicodeLowercase/Unicode_mixedcase_end-4     1.000 ± 0%     1.000 ± 0%       ~ (p=1.000 n=10) ¹
geomean                                                 ²               +0.00%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean
```

I think the `+7%` for the lowercase Latin1 testcase is easily outweighed
by the ASCII and unicode improvements 🙂

2025-04-01 13:41:57 +02:00

..

basicfs_copy_range_copyfilerange.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_copy_range_duplicateextents.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_copy_range_ioctl.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_copy_range_sendfile.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_copy_range.go

lib/fs: Unwrap mtimeFile, get fd the "correct" way (ref #6875) (#6877)

2020-08-07 07:47:48 +02:00

basicfs_fileinfo_bsdish.go

all: Support syncing extended attributes (fixes #2698) (#8513)

2022-09-14 09:50:55 +02:00

basicfs_fileinfo_linuxish.go

lib/fs: Ignore inode change time on Android (#9177)

2023-10-21 08:24:29 +02:00

basicfs_fileinfo_unix.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_fileinfo_windows.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

basicfs_lstat_broken.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_lstat_regular.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_lstat_windows.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

basicfs_platformdata_unix.go

refactor: use modern Protobuf encoder (#9817)

2024-12-01 16:50:17 +01:00

basicfs_platformdata_windows.go

all: Support syncing extended attributes (fixes #2698) (#8513)

2022-09-14 09:50:55 +02:00

basicfs_test.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

basicfs_unix.go

lib/fs: Try to remove read only Windows files (fixes #3744) (#8650)

2022-11-07 21:33:17 +01:00

basicfs_watch_errors_linux.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_watch_errors_others.go

refactor: use modern Protobuf encoder (#9817)

2024-12-01 16:50:17 +01:00

basicfs_watch_eventtypes_darwin.go

all: minimal set of changes for iOS app (#9619)

2024-07-31 07:31:14 +02:00

basicfs_watch_eventtypes_fen.go

lib/fs: Do not follow symlinks in watcher on solaris (fixes #8020) (#8223)

2022-03-24 08:36:43 +01:00

basicfs_watch_eventtypes_inotify.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_watch_eventtypes_kqueue.go

chore(fs): build kqueue instead of fsevents watcher on iOS (#9950)

2025-02-07 15:40:53 +00:00

basicfs_watch_eventtypes_other.go

all: minimal set of changes for iOS app (#9619)

2024-07-31 07:31:14 +02:00

basicfs_watch_eventtypes_readdcw.go

all: Update build constraints to Go 1.17 style (#7894)

2021-08-17 10:10:41 +02:00

basicfs_watch_notkqueue.go

chore(fs): build kqueue instead of fsevents watcher on iOS (#9950)

2025-02-07 15:40:53 +00:00

basicfs_watch_test.go

lib/ignore: Refactor out result type (#9343)

2024-01-13 18:58:23 +01:00

basicfs_watch_unsupported.go

chore(fs): build kqueue instead of fsevents watcher on iOS (#9950)

2025-02-07 15:40:53 +00:00

basicfs_watch.go

chore(fs): build kqueue instead of fsevents watcher on iOS (#9950)

2025-02-07 15:40:53 +00:00

basicfs_windows_test.go

build: Tests should run with Go 1.20 on Windows (#8924)

2023-06-05 10:19:47 +02:00

basicfs_windows.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

basicfs_xattr_bsdish.go

all: Fix typos found by codespell (#8833)

2023-03-21 08:07:28 +01:00

basicfs_xattr_linuxish.go

all: Support syncing extended attributes (fixes #2698) (#8513)

2022-09-14 09:50:55 +02:00

basicfs_xattr_unix.go

lib/fs: Reduce memory usage in xattrs handling (#9251)

2023-12-04 12:48:17 +01:00

basicfs_xattr_unsupported.go

refactor: use modern Protobuf encoder (#9817)

2024-12-01 16:50:17 +01:00

basicfs.go

lib/upgrade: Send OS version header to upgrade server (#9663)

2024-08-28 08:31:10 +02:00

casefs_test.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

casefs.go

chore(fs): add debug logging for case cache registry (#9869)

2024-12-16 12:04:24 +01:00

copyrangemethod.go

refactor: use modern Protobuf encoder (#9817)

2024-12-01 16:50:17 +01:00

debug.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

errorfs.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

fakefs_test.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

fakefs.go

lib/fs: Add test reproducing missing mtimefs issue (ref #9677) (#9687)

2024-09-10 13:36:17 +02:00

filesystem_copy_range_allwithfallback.go

lib/fs: Add support for Windows duplicate extents (#6764)

2020-06-18 22:32:26 +01:00

filesystem_copy_range_standard.go

all: Add copy-on-write filesystem support (fixes #4271) (#6746)

2020-06-18 08:15:47 +02:00

filesystem_copy_range_test.go

all: Add Prometheus-style metrics to expose some internal performance counters (fixes #5175) (#9003)

2023-08-04 19:57:30 +02:00

filesystem_copy_range.go

all: Add copy-on-write filesystem support (fixes #4271) (#6746)

2020-06-18 08:15:47 +02:00

filesystem_test.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

filesystem.go

chore(fs): put the caseFS as the outermost layer again (#9716)

2024-09-18 20:31:19 +02:00

folding_test.go

chore(fs): speed up case normalization (#10013)

2025-04-01 13:41:57 +02:00

folding.go

chore(fs): speed up case normalization (#10013)

2025-04-01 13:41:57 +02:00

logfs.go

chore(fs): put the caseFS as the outermost layer again (#9716)

2024-09-18 20:31:19 +02:00

metrics.go

lib/fs, lib/model: Be careful about potentially negative durations (fixes #9112) (#9113)

2023-09-20 09:04:47 +02:00

mtimefs_test.go

all: Add Prometheus-style metrics to expose some internal performance counters (fixes #5175) (#9003)

2023-08-04 19:57:30 +02:00

mtimefs.go

lib/fs: Better equality comparison in mtimefs

2023-12-03 16:01:46 +01:00

platform_common.go

all: Support syncing extended attributes (fixes #2698) (#8513)

2022-09-14 09:50:55 +02:00

tempname_test.go

lib/fs: Optimize TempName + some cosmetic changes (#7911)

2021-08-29 10:47:53 +02:00

tempname.go

lib/sha256: Remove it (#9643)

2024-08-10 12:58:20 +01:00

types.go

refactor: use modern Protobuf encoder (#9817)

2024-12-01 16:50:17 +01:00

util_test.go

lib/fs: Clarify errors for Windows filenames (fixes #8968) (#8969)

2023-07-07 11:00:40 +00:00

util.go

lib/fs: Clarify errors for Windows filenames (fixes #8968) (#8969)

2023-07-07 11:00:40 +00:00

walkfs_test.go

style: gofumpt all the things (#9829)

2024-11-19 11:32:56 +01:00

walkfs.go

all: Remove unused method receivers (#8462)

2022-07-28 17:32:45 +02:00