pgrep: use regex to replace stat_split function and add some tests

[Franklin-Qi]

Use regex to replace stat_split function and add some tests in test_stat_split function.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.19%. Comparing base (ee98c0a) to head (d7dbb2c).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/uu/pgrep/src/process.rs	0.00%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #663   +/-   ##
=======================================
  Coverage   19.19%   19.19%           
=======================================
  Files          68       68           
  Lines       10135    10135           
  Branches      545      545           
=======================================
  Hits         1945     1945           
  Misses       8190     8190           

Flag	Coverage Δ
macos_latest	6.74% <0.00%> (ø)
ubuntu_latest	19.54% <0.00%> (ø)
windows_latest	0.02% <0.00%> (ø)

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

☔ View full report in Codecov by Sentry.
📢 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.

[Franklin-Qi]

The codecov/patch is currently throwing an error, but I have already added different test cases to the unit tests. Do I need to add additional unit test cases in the test_stat_split function? @sylvestre @Krysztal112233

[Krysztal112233]

could you please use hyperfine to create a small benchmark to demonstrate the performance improvement? I'd like to see how much this change improves performance.

[Krysztal112233]

The codecov/patch is currently throwing an error, but I have already added different test cases to the unit tests. Do I need to add additional unit test cases in the test_stat_split function? @sylvestre @Krysztal112233

I don't think it's required, this pr doesn't involve any more changes to the implementation :)

[Franklin-Qi]

could you please use hyperfine to create a small benchmark to demonstrate the performance improvement? I'd like to see how much this change improves performance.

@Krysztal112233 Thanks for your review. Below are the performance tests I performed using hyperfine on the unmodified main branch and the modified use-regex-to-replace-stat_split-function for cargo test --package uu_pgrep.

$ LC_ALL=C hyperfine   --warmup 3   --runs 10 --show-output --command-name "main (old version)"   --prepare "git switch main"   "cargo test --package uu_pgrep"   --command-name "use-regex-to-replace-stat_split-function (new version)"   --prepare "git switch use-regex-to-replace-stat_split-function"   "cargo test --package uu_pgrep"
Benchmark 1: main (old version)
Switched to branch 'main'
Your branch is up to date with 'origin/main'.
   Compiling uu_pgrep v0.0.1 (/home/ysq/code/procps/src/uu/pgrep)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.81s
     Running unittests src/pgrep.rs (target/debug/deps/uu_pgrep-58e1985eaa5ab062)

running 13 tests
test process::tests::test_run_state_conversion ... ok
test process::tests::test_ids ... ok
test process::tests::test_cgroups ... ok
test process::tests::test_stat_split ... ok
test process::tests::test_environ ... ok
test process::tests::test_namespaces ... ok
test process::tests::test_root ... ok
test process::tests::test_thread_ids ... ok
test process::tests::test_uid_gid ... ok
test process::tests::test_pid_entry ... ok
test process::tests::test_tty_resolution ... ok
test process_matcher::test_parse_pidfile_content_valid ... ok
test process::tests::test_walk_pid ... ok

test result: ok. 13 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.04s

     Running unittests src/main.rs (target/debug/deps/pgrep-78957d45a885038f)

...

running 13 tests
test process::tests::test_cgroups ... ok
test process::tests::test_namespaces ... ok
test process::tests::test_root ... ok
test process::tests::test_run_state_conversion ... ok
test process::tests::test_thread_ids ... ok
test process::tests::test_uid_gid ... ok
test process::tests::test_environ ... ok
test process::tests::test_ids ... ok
test process::tests::test_stat_split ... ok
test process::tests::test_pid_entry ... ok
test process::tests::test_tty_resolution ... ok
test process_matcher::test_parse_pidfile_content_valid ... ok
test process::tests::test_walk_pid ... ok

test result: ok. 13 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.02s

     Running unittests src/main.rs (target/debug/deps/pgrep-78957d45a885038f)

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests uu_pgrep

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

  Time (mean ± σ):     240.5 ms ±  10.1 ms    [User: 201.5 ms, System: 79.1 ms]
  Range (min … max):   230.7 ms … 263.5 ms    10 runs
 
Summary
  use-regex-to-replace-stat_split-function (new version) ran
    1.06 ± 0.11 times faster than main (old version)