path: remove unnecessary string copies #14438

tniessen · 2017-07-23T20:11:27Z

The length of path is known, so path.slice(0, len) === path. Unless I am missing something, these calls are unnecessary.

Partial CI: https://ci.nodejs.org/job/node-test-commit-linuxone/7511/

Checklist

make -j4 test (UNIX), or vcbuild test (Windows) passes
commit message follows commit guidelines

Affected core subsystem(s)

path

At this line, `path` has a length of 2, so `path.slice(0, 2) === path`.

mscdex · 2017-07-23T20:51:05Z

Could you add a test for the second change? It seems that line is not currently covered and it would be good to check that the same result is returned before and after this PR.

refack · 2017-07-23T21:14:22Z

@tniessen If you're adding new tests, see if you can cover the if (code === 47/*/*/ || code === 92/*\*/) from L1057

TimothyGu · 2017-07-24T06:05:30Z

lib/path.js

@@ -1049,7 +1049,7 @@ const win32 = {
          } else {
            // `path` contains just a drive root, exit early to avoid
            // unnecessary work
-            ret.root = ret.dir = path.slice(0, 2);
+            ret.root = ret.dir = path;
            return ret;
          }
        }


The

ret.root = ret.dir = path[0];

below can be simplified to

ret.root = ret.dir = path;

as well, AFAICT.

Anyway could you add a comment // `(len <= 1)`

cjihrig

LGTM with a test.

tniessen · 2017-07-24T14:26:17Z

@refack

tniessen · 2017-07-24T15:26:08Z

CI: https://ci.nodejs.org/job/node-test-pull-request/9322/

refack

💯

XadillaX

LGTM.

As the length of `path` is known at this point, there is no point in making an exact copy using `slice`. PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

tniessen · 2017-07-26T12:02:54Z

Landed in 2ac0aff f7f590c

CI on master: https://ci.nodejs.org/job/node-test-commit-linuxone/7567/

As the length of `path` is known at this point, there is no point in making an exact copy using `slice`. PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

addaleax · 2017-07-27T22:30:42Z

The second commit (f7f590c) doesn’t land cleanly on 8.x; if you can, please follow the guide and raise a backport PR, if you don’t think it’s worth it let me know/add the dont-land-on label.

PR-URL: nodejs#14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

Backport-PR-URL: #14521 Backport-Reviewed-By: Anna Henningsen <anna@addaleax.net> PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

TimothyGu · 2017-08-12T10:23:22Z

I'll handle backporting this to v6.x together with #14440.

Edit: done in #14787

As the length of `path` is known at this point, there is no point in making an exact copy using `slice`. PR-URL: nodejs#14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

Backport-PR-URL: #14787 PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

As the length of `path` is known at this point, there is no point in making an exact copy using `slice`. Backport-PR-URL: #14787 PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

Backport-PR-URL: #14787 PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

As the length of `path` is known at this point, there is no point in making an exact copy using `slice`. Backport-PR-URL: #14787 PR-URL: #14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

PR-URL: nodejs/node#14438 Reviewed-By: Refael Ackermann <refack@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Khaidi Chu <i@2333.moe>

tniessen added 2 commits July 23, 2017 21:48

path: remove unnecessary string copy

6aff340

At this line, `path` has a length of 2, so `path.slice(0, 2) === path`.

path: remove unnecessary string copy

530f300

tniessen added the path Issues and PRs related to the path subsystem. label Jul 23, 2017

tniessen self-assigned this Jul 23, 2017

tniessen requested a review from refack July 23, 2017 20:11

nodejs-github-bot added the path Issues and PRs related to the path subsystem. label Jul 23, 2017

addaleax approved these changes Jul 23, 2017

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refack approved these changes Jul 23, 2017

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jasnell approved these changes Jul 24, 2017

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lpinca approved these changes Jul 24, 2017

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TimothyGu reviewed Jul 24, 2017

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More optimizations

8a07118

cjihrig approved these changes Jul 24, 2017

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add tests

25d9601

add more detailed tests

fdbffaf

refack approved these changes Jul 24, 2017

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XadillaX approved these changes Jul 25, 2017

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TimothyGu approved these changes Jul 25, 2017

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tniessen closed this Jul 26, 2017

addaleax added the backport-requested-v8.x label Jul 27, 2017

tniessen mentioned this pull request Jul 27, 2017

[v8.x backport] test: increase coverage for path.parse #14521

Closed

addaleax added backported-to-v8.x and removed backport-requested-v8.x labels Jul 27, 2017

addaleax mentioned this pull request Aug 2, 2017

v8.3.0 proposal #14594

Merged

TimothyGu added the backport-requested-v6.x label Aug 12, 2017

TimothyGu mentioned this pull request Aug 12, 2017

[v6.x backport] path.win32 related fixes and tests #14787

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MylesBorins added backported-to-v6.x and removed backport-requested-v6.x labels Aug 14, 2017

MylesBorins mentioned this pull request Aug 16, 2017

v6.11.3-proposal #14852

Merged

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path: remove unnecessary string copies #14438

path: remove unnecessary string copies #14438

tniessen commented Jul 23, 2017

mscdex commented Jul 23, 2017

refack commented Jul 23, 2017 •

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path: remove unnecessary string copies #14438

path: remove unnecessary string copies #14438

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tniessen commented Jul 23, 2017

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Affected core subsystem(s)

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