From: Charlie Vieth <charlie.vieth@gmail.com>
Date: Sat, 12 Mar 2022 22:27:42 +0000 (-0500)
Subject: go/build: replace ioutil.ReadDir with os.ReadDir
X-Git-Tag: go1.19beta1~306
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=536282763f7357edd81d85993c12fd977fecd378;p=gostls13.git

go/build: replace ioutil.ReadDir with os.ReadDir

Change go/build.readDir to use os.ReadDir instead of ioutil.ReadDir.
This addresses a TODO and improves performance on Darwin and Linux.

Darwin: Apple M1
name              old time/op    new time/op    delta
ImportVendor-10     39.8µs ± 1%    37.0µs ± 1%  -6.91%  (p=0.000 n=10+10)

Linux: Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
name              old time/op    new time/op    delta
ImportVendor-16     22.9µs ±11%    21.2µs ± 5%  -7.47%  (p=0.001 n=10+9)

Updates #45557

Change-Id: Ib1bd2e66210e714e499a035847d6261b61b7e2c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/392074
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
---

diff --git a/src/go/build/build.go b/src/go/build/build.go
index 836e279d92..039b422dab 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -17,7 +17,6 @@ import (
 	"internal/goversion"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	pathpkg "path"
@@ -186,13 +185,21 @@ func hasSubdir(root, dir string) (rel string, ok bool) {
 	return filepath.ToSlash(dir[len(root):]), true
 }
 
-// readDir calls ctxt.ReadDir (if not nil) or else ioutil.ReadDir.
-func (ctxt *Context) readDir(path string) ([]fs.FileInfo, error) {
+// readDir calls ctxt.ReadDir (if not nil) or else os.ReadDir.
+func (ctxt *Context) readDir(path string) ([]fs.DirEntry, error) {
+	// TODO: add a fs.DirEntry version of Context.ReadDir
 	if f := ctxt.ReadDir; f != nil {
-		return f(path)
+		fis, err := f(path)
+		if err != nil {
+			return nil, err
+		}
+		des := make([]fs.DirEntry, len(fis))
+		for i, fi := range fis {
+			des[i] = fs.FileInfoToDirEntry(fi)
+		}
+		return des, nil
 	}
-	// TODO: use os.ReadDir
-	return ioutil.ReadDir(path)
+	return os.ReadDir(path)
 }
 
 // openFile calls ctxt.OpenFile (if not nil) or else os.Open.
@@ -836,7 +843,7 @@ Found:
 		if d.IsDir() {
 			continue
 		}
-		if d.Mode()&fs.ModeSymlink != 0 {
+		if d.Type() == fs.ModeSymlink {
 			if ctxt.isDir(ctxt.joinPath(p.Dir, d.Name())) {
 				// Symlinks to directories are not source files.
 				continue
diff --git a/src/go/build/build_test.go b/src/go/build/build_test.go
index 36bcae179e..8fa17c7343 100644
--- a/src/go/build/build_test.go
+++ b/src/go/build/build_test.go
@@ -567,6 +567,27 @@ func TestImportVendor(t *testing.T) {
 	}
 }
 
+func BenchmarkImportVendor(b *testing.B) {
+	testenv.MustHaveGoBuild(b) // really must just have source
+
+	b.Setenv("GO111MODULE", "off")
+
+	ctxt := Default
+	wd, err := os.Getwd()
+	if err != nil {
+		b.Fatal(err)
+	}
+	ctxt.GOPATH = filepath.Join(wd, "testdata/withvendor")
+	dir := filepath.Join(ctxt.GOPATH, "src/a/b")
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := ctxt.Import("c/d", dir, 0)
+		if err != nil {
+			b.Fatalf("cannot find vendored c/d from testdata src/a/b directory: %v", err)
+		}
+	}
+}
+
 func TestImportVendorFailure(t *testing.T) {
 	testenv.MustHaveGoBuild(t) // really must just have source