path: improve path.resolve() performance when used as process.cwd()

`path.resolve()` and `path.resolve('.')` is frequently called as alternative to process.cwd(). This minimized overhead for these specific cases. PR-URL: #58362 Reviewed-By: Jordan Harband <ljharb@gmail.com> Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com> Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>

Author: BridgeAR

benchmark/path/join-posix.js

@@ -16,8 +16,8 @@ function main({ n, paths }) {
 
  bench.start();
  for (let i = 0; i < n; i++) {
- if (i % 3 === 0) {
- copy[1] = `${orig}${i}`;
+ if (i % 5 === 0) {
+ copy[1] = `${orig}/${i}`;
  posix.join(...copy);
  } else {
  posix.join(...args);

benchmark/path/join-win32.js

@@ -16,8 +16,8 @@ function main({ n, paths }) {
 
  bench.start();
  for (let i = 0; i < n; i++) {
- if (i % 3 === 0) {
- copy[1] = `${orig}${i}`;
+ if (i % 5 === 0) {
+ copy[1] = `${orig}\\${i}`;
  win32.join(...copy);
  } else {
  win32.join(...args);

benchmark/path/normalize-posix.js

@@ -17,7 +17,7 @@ const bench = common.createBenchmark(main, {
 function main({ n, path }) {
  bench.start();
  for (let i = 0; i < n; i++) {
- posix.normalize(i % 3 === 0 ? `${path}${i}` : path);
+ posix.normalize(i % 5 === 0 ? `${path}/${i}` : path);
  }
  bench.end(n);
 }

benchmark/path/normalize-win32.js

@@ -17,7 +17,7 @@ const bench = common.createBenchmark(main, {
 function main({ n, path }) {
  bench.start();
  for (let i = 0; i < n; i++) {
- win32.normalize(i % 3 === 0 ? `${path}${i}` : path);
+ win32.normalize(i % 5 === 0 ? `${path}\\${i}` : path);
  }
  bench.end(n);
 }

benchmark/path/resolve-posix.js

@@ -4,23 +4,26 @@ const { posix } = require('path');
 
 const bench = common.createBenchmark(main, {
  paths: [
+ 'empty',
  '',
+ '.',
  ['', ''].join('|'),
  ['foo/bar', '/tmp/file/', '..', 'a/../subfile'].join('|'),
  ['a/b/c/', '../../..'].join('|'),
+ ['/a/b/c/', 'abc'].join('|'),
  ],
  n: [1e5],
 });
 
 function main({ n, paths }) {
- const args = paths.split('|');
+ const args = paths === 'empty' ? [] : paths.split('|');
  const copy = [...args];
- const orig = copy[0];
+ const orig = copy[0] ?? '';
 
  bench.start();
  for (let i = 0; i < n; i++) {
- if (i % 3 === 0) {
- copy[0] = `${orig}${i}`;
+ if (i % 5 === 0) {
+ copy[0] = `${orig}/${i}`;
  posix.resolve(...copy);
  } else {
  posix.resolve(...args);

benchmark/path/resolve-win32.js

@@ -4,7 +4,9 @@ const { win32 } = require('path');
 
 const bench = common.createBenchmark(main, {
  paths: [
+ 'empty',
  '',
+ '.',
  ['', ''].join('|'),
  ['c:/ignore', 'd:\\a/b\\c/d', '\\e.exe'].join('|'),
  ['c:/blah\\blah', 'd:/games', 'c:../a'].join('|'),
@@ -13,14 +15,14 @@ const bench = common.createBenchmark(main, {
 });
 
 function main({ n, paths }) {
- const args = paths.split('|');
+ const args = paths === 'empty' ? [] : paths.split('|');
  const copy = [...args];
- const orig = copy[0];
+ const orig = copy[0] ?? '';
 
  bench.start();
  for (let i = 0; i < n; i++) {
- if (i % 3 === 0) {
- copy[0] = `${orig}${i}`;
+ if (i % 5 === 0) {
+ copy[0] = `${orig}\\${i}`;
  win32.resolve(...copy);
  } else {
  win32.resolve(...args);

lib/path.js

@@ -95,7 +95,7 @@ function normalizeString(path, allowAboveRoot, separator, isPathSeparator) {
  StringPrototypeCharCodeAt(res, res.length - 1) !== CHAR_DOT ||
  StringPrototypeCharCodeAt(res, res.length - 2) !== CHAR_DOT) {
  if (res.length > 2) {
- const lastSlashIndex = StringPrototypeLastIndexOf(res, separator);
+ const lastSlashIndex = res.length - lastSegmentLength - 1;
  if (lastSlashIndex === -1) {
  res = '';
  lastSegmentLength = 0;
@@ -163,6 +163,8 @@ function _format(sep, pathObject) {
  return dir === pathObject.root ? `${dir}${base}` : `${dir}${sep}${base}`;
 }
 
+const forwardSlashRegExp = /\//g;
+
 const win32 = {
  /**
  * path.resolve([from ...], to)
@@ -186,6 +188,14 @@ const win32 = {
  }
  } else if (resolvedDevice.length === 0) {
  path = process.cwd();
+ // Fast path for current directory
+ if (args.length === 0 || ((args.length === 1 && (args[0] === '' || args[0] === '.')) &&
+ isPathSeparator(StringPrototypeCharCodeAt(path, 0)))) {
+ if (!isWindows) {
+ path = StringPrototypeReplace(path, forwardSlashRegExp, '\\');
+ }
+ return path;
+ }
  } else {
  // Windows has the concept of drive-specific current working
  // directories. If we've resolved a drive letter but not yet an
@@ -1171,6 +1181,12 @@ const posix = {
  * @returns {string}
  */
  resolve(...args) {
+ if (args.length === 0 || (args.length === 1 && (args[0] === '' || args[0] === '.'))) {
+ const cwd = posixCwd();
+ if (StringPrototypeCharCodeAt(cwd, 0) === CHAR_FORWARD_SLASH) {
+ return cwd;
+ }
+ }
  let resolvedPath = '';
  let resolvedAbsolute = false;
 

test/parallel/test-path-resolve.js

@@ -24,6 +24,8 @@ const resolveTests = [
  [['c:/ignore', 'd:\\a/b\\c/d', '\\e.exe'], 'd:\\e.exe'],
  [['c:/ignore', 'c:/some/file'], 'c:\\some\\file'],
  [['d:/ignore', 'd:some/dir//'], 'd:\\ignore\\some\\dir'],
+ [[], process.cwd()],
+ [[''], process.cwd()],
  [['.'], process.cwd()],
  [['//server/share', '..', 'relative\\'], '\\\\server\\share\\relative'],
  [['c:/', '//'], 'c:\\'],
@@ -42,6 +44,8 @@ const resolveTests = [
  [[['/var/lib', '../', 'file/'], '/var/file'],
  [['/var/lib', '/../', 'file/'], '/file'],
  [['a/b/c/', '../../..'], posixyCwd],
+ [[], posixyCwd],
+ [[''], posixyCwd],
  [['.'], posixyCwd],
  [['/some/dir', '.', '/absolute/'], '/absolute'],
  [['/foo/tmp.3/', '../tmp.3/cycles/root.js'], '/foo/tmp.3/cycles/root.js'],