fs: add c++ fast path for writeFileSync string utf8

[CanadaHonk]

Summary

Added fast path in almost entirely C++ for writeFileSync with UTF8 encoding and string data. Also improves appendFileSync as it just uses writeFileSync under the hood. Only string data as Buffer seems questionable in benchmarks for this so I'll just leave it for strings for now.

TL;DR: This makes writeFileSync(path, data: string) UTF8 up to ~2.5x faster depending on data size, especially when using file descriptors

Bench results

Benchmark in this PR

Note: running locally on Linux/i9/SSD

 confidence improvement accuracy (*) (**) (***) fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=1024 useFd='false' encoding='utf8' -0.37 % ±4.40% ±5.90% ±7.77% fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=1024 useFd='true' encoding='utf8' *** 49.15 % ±5.11% ±6.82% ±8.91% fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=102400 useFd='false' encoding='utf8' *** 6.69 % ±1.67% ±2.22% ±2.89% fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=102400 useFd='true' encoding='utf8' *** 74.52 % ±4.35% ±5.85% ±7.74% fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=1048576 useFd='false' encoding='utf8' *** 16.05 % ±1.60% ±2.14% ±2.81% fs/bench-writeFileSync.js n=1000 func='writeFile' useBuffer='false' length=1048576 useFd='true' encoding='utf8' *** 85.82 % ±3.58% ±4.77% ±6.23% 

Benchmark CI (old): https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1421/

Alternative benchmark

Alternative benchmark using Bun's bench for fs.copyFileSync (string data, using paths)

Current (main)

benchmark time (avg) (min … max) p75 p99 p995 ------------------------------------------------------ ----------------------------- 12 ascii 2.19 µs/iter (2.07 µs … 2.67 µs) 2.21 µs 2.67 µs 2.67 µs 12 utf8 2.23 µs/iter (2.08 µs … 2.32 µs) 2.26 µs 2.32 µs 2.32 µs 12288 ascii 6.14 µs/iter (5.97 µs … 6.62 µs) 6.14 µs 6.62 µs 6.62 µs 18432 utf8 40.02 µs/iter (36.13 µs … 204.16 µs) 40.05 µs 63.6 µs 69.01 µs 

This PR

Long ascii: 6.14µs -> 3.46µs (~1.8x speedup)
Long utf8: 40.02µs -> 18.25µs (~2.2x speedup)

benchmark time (avg) (min … max) p75 p99 p995 ------------------------------------------------------ ----------------------------- 12 ascii 1.97 µs/iter (1.9 µs … 2.03 µs) 1.98 µs 2.03 µs 2.03 µs 12 utf8 1.95 µs/iter (1.91 µs … 2 µs) 1.97 µs 2 µs 2 µs 12288 ascii 3.46 µs/iter (3.39 µs … 3.6 µs) 3.47 µs 3.6 µs 3.6 µs 18432 utf8 18.25 µs/iter (16.06 µs … 147.95 µs) 18.48 µs 21.77 µs 24.03 µs 

[github-actions]

The notable-changePRs with changes that should be highlighted in changelogs. label has been added by @anonrig.

Please suggest a text for the release notes if you'd like to include a more detailed summary, then proceed to update the PR description with the text or a link to the notable change suggested text comment.

[CanadaHonk]

Rebased on latest main and addressed various review comments. Should be good for review fully now.

[anonrig]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/1421/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/54266/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/54269/

[CanadaHonk]

@santigimeno and/or @bnoordhuis, would you mind checking/reviewing the latest revision? Uses a write loop like original JS source now. Thanks!

[jeremymeng]

Some of our tests using writeFileSync are now broken in 21.3.0 #50989

Is this related?

[ChALkeR]

Was flush option considered here?
This landed after #50009

[ChALkeR]

base64 writes are also a thing, as it covers binary writes when content is already in base64
and could also be optimized via a fast path (e.g. by adding an encoding parameter here)

7113870 selenium-webdriver-4.38.0.tgz/lib/webdriver.js:1742: fs.writeFileSync(zipFilePath, Buffer.from(base64Content, 'base64')) 1563070 cucumber-html-reporter-7.2.0.tgz/lib/reporter.js:320: fs.writeFileSync(filename, embedding.data, 'base64'); 1563070 cucumber-html-reporter-7.2.0.tgz/lib/reporter.js:334: fs.writeFileSync(filename, embedding.data, 'base64'); 313200 @loki/diff-looks-same-0.35.0.tgz/src/create-looks-same-differ.spec.js:13: fs.writeFileSync(outputPath, imageData,{encoding: 'base64' }); 307699 @loki/diff-pixelmatch-0.35.0.tgz/src/create-pixelmatch-differ.spec.js:13: fs.writeFileSync(outputPath, imageData,{encoding: 'base64' }); 204239 backstopjs-6.3.25.tgz/core/util/compare/store-failed-diff-stub.js:10: fs.writeFileSync(getFailedDiffFilename(testPath), BASE64_PNG_STUB, 'base64'); 195127 vscode-extension-tester-8.19.0.tgz/out/browser.js:233: fs.writeFileSync(path.join(dir, `${name}.png`), data, 'base64'); 82614 base64-img-1.0.4.tgz/base64-img.js:113: fs.writeFileSync(filepath, result.base64,{encoding: 'base64' }); 74527 remove.bg-1.3.0.tgz/index.js:77: fs.writeFileSync(options.outputFile, result.body.data.result_b64,{encoding: "base64" }); 73121 pxt-core-12.2.3.tgz/built/cli.js:2936: nodeutil.writeFileSync(p, contents,{encoding: "base64" }); 73121 pxt-core-12.2.3.tgz/built/pxt.js:165454: nodeutil.writeFileSync(p, contents,{encoding: "base64" }); ... 

Left column is downloads/month

selenium-webdriver needs a fix though: SeleniumHQ/selenium#16542