fast_io.rs: use splice if copy_file_range is not supported by Franklin-Qi · Pull Request #459 · uutils/sed

Franklin-Qi · 2026-06-05T07:29:13Z

fast_io.rs: use splice if copy_file_range is not supported

Prefer splice (via rustix) for file→pipe output, and enlarge the pipe buffer when possible.
Fall back in reliable_copy_file_range with copy_file_range → splice (middle pipe) → write, advancing in_ptr correctly after a partial copy.
Cover the paths with Linux unit tests and an end-to-end large-file pipe-through-sed test.
If splice becomes unsupported after some bytes were already sent, return Some(copied) so the write fallback only emits the remainder.

Closes: #443

codecov · 2026-06-05T07:33:57Z

Codecov Report

❌ Patch coverage is 85.14056% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.93%. Comparing base (f7fb0d7) to head (49fe557).

Files with missing lines	Patch %	Lines
src/sed/fast_io.rs	85.02%	37 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #459      +/-   ##
==========================================
+ Coverage   83.86%   83.93%   +0.06%     
==========================================
  Files          14       14              
  Lines        7203     7444     +241     
  Branches      424      438      +14     
==========================================
+ Hits         6041     6248     +207     
- Misses       1157     1191      +34     
  Partials        5        5

Flag	Coverage Δ
macos_latest	`85.00% <92.00%> (+0.02%)`	⬆️
ubuntu_latest	`85.20% <85.36%> (+0.03%)`	⬆️
windows_latest	`0.00% <0.00%> (ø)`

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

oech3 · 2026-06-12T03:32:38Z

sendfile is internally splice. So no worth to try it. splice with middler pipe is faster.

oech3 · 2026-06-12T03:52:20Z

Please use rustix instead of unsafe libc.

sylvestre · 2026-08-08T22:53:41Z

@Franklin-Qi sorry, it needs to be rebased

codspeed · 2026-08-12T00:46:16Z

Merging this PR will not alter performance

✅ 11 untouched benchmarks

_{Comparing Franklin-Qi:fix-#443-use-sendfile-or-splice-if-copy-file-range-is-not-supported (49fe557) with main (f7fb0d7)}

oech3 · 2026-08-15T10:12:11Z

remove sendfile from PR's title and the commit message.

sylvestre · 2026-08-29T21:24:46Z

@Franklin-Qi ping?

Franklin-Qi · 2026-08-31T05:54:11Z

@Franklin-Qi ping?

Yeah, I will deal with this issue soon. @sylvestre

- Prefer splice (via rustix) for file→pipe output, and enlarge the pipe buffer when possible. - Fall back in reliable_copy_file_range with copy_file_range → splice (middle pipe) → write, advancing in_ptr correctly after a partial copy. - Cover the paths with Linux unit tests and an end-to-end large-file pipe-through-sed test. Closes: uutils#443

If splice becomes unsupported after some bytes were already sent, return Some(copied) so the write fallback only emits the remainder.

Franklin-Qi force-pushed the fix-#443-use-sendfile-or-splice-if-copy-file-range-is-not-supported branch from cee18ce to 581e725 Compare June 5, 2026 07:57

oech3 reviewed Aug 5, 2026

View reviewed changes

Comment thread src/sed/fast_io.rs Outdated

Comment thread src/sed/fast_io.rs Outdated

Comment thread src/sed/fast_io.rs Outdated

Comment thread src/sed/fast_io.rs Outdated

Comment thread src/sed/fast_io.rs Outdated

Comment thread src/sed/fast_io.rs Outdated

Franklin-Qi force-pushed the fix-#443-use-sendfile-or-splice-if-copy-file-range-is-not-supported branch from 581e725 to bd5b0e2 Compare August 12, 2026 00:35

Franklin-Qi force-pushed the fix-#443-use-sendfile-or-splice-if-copy-file-range-is-not-supported branch 5 times, most recently from 7551756 to 1889db5 Compare August 12, 2026 01:34

oech3 reviewed Aug 12, 2026

View reviewed changes