List files in a directory using golang

list_directory.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
)

func main() {
	var (
    		root string
    		files []string
    		err error
	  )	

	if len(os.Args) == 1 {
		log.Fatal("No path given, Please specify path.")
		return
	}
	if root = os.Args[1]; root == "" {
		log.Fatal("No path given, Please specify path.")
		return
	}
	// filepath.Walk
	 files, err = FilePathWalkDir(root)
	 if err != nil {
	 	panic(err)
	 }
	// ioutil.ReadDir
	 files, err = IOReadDir(root)
	 if err != nil {
	 	panic(err)
	 }
	//os.File.Readdir
	files, err = OSReadDir(root)
	if err != nil {
		panic(err)
	}

	for _, file := range files {
		fmt.Println(file)
	}
}

list_directory_filepath_walk.go

func FilePathWalkDir(root string) ([]string, error) {
	var files []string
	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if !info.IsDir() {
			files = append(files, path)
		}
		return nil
	})
	return files, err
}

list_directory_helpers.go

func FpW(n int, root string) {
	for i := 0; i < n; i++ {
		FilePathWalkDir(root)
	}
}
func IoRdir(n int, root string) {
	for i := 0; i < n; i++ {
		IOReadDir(root)
	}
}
func OsRdir(n int, root string) {
	for i := 0; i < n; i++ {
		OSReadDir(root)
	}
}

list_directory_ioutil_readdir.go

func IOReadDir(root string) ([]string, error) {
	var files []string
	fileInfo, err := ioutil.ReadDir(root)
	if err != nil {
		return files, err
	}

	for _, file := range fileInfo {
		files = append(files, file.Name())
	}
	return files, nil
}

list_directory_osfile_readdir.go

func OSReadDir(root string) ([]string, error) {
	var files []string
	f, err := os.Open(root)
	if err != nil {
		return files, err
	}
	fileInfo, err := f.Readdir(-1)
	f.Close()
	if err != nil {
		return files, err
	}

	for _, file := range fileInfo {
		files = append(files, file.Name())
	}
	return files, nil
}

list_directory_test.go

package main

import (
	"testing"
)

var root string = "/home/manigandan/Desktop/Manigandan/sample"

func BenchmarkFilePathWalkDir1(b *testing.B)  { benchmarkFilePathWalkDir(1, root, b) }
func BenchmarkFilePathWalkDir2(b *testing.B)  { benchmarkFilePathWalkDir(2, root, b) }
func BenchmarkFilePathWalkDir3(b *testing.B)  { benchmarkFilePathWalkDir(3, root, b) }
func BenchmarkFilePathWalkDir10(b *testing.B) { benchmarkFilePathWalkDir(10, root, b) }
func BenchmarkFilePathWalkDir20(b *testing.B) { benchmarkFilePathWalkDir(20, root, b) }
func BenchmarkFilePathWalkDir30(b *testing.B) { benchmarkFilePathWalkDir(30, root, b) }
func BenchmarkFilePathWalkDir40(b *testing.B) { benchmarkFilePathWalkDir(40, root, b) }
func BenchmarkFilePathWalkDir50(b *testing.B) { benchmarkFilePathWalkDir(50, root, b) }

func BenchmarkIOReadDir1(b *testing.B)  { benchmarkIOReadDir(1, root, b) }
func BenchmarkIOReadDir2(b *testing.B)  { benchmarkIOReadDir(2, root, b) }
func BenchmarkIOReadDir3(b *testing.B)  { benchmarkIOReadDir(3, root, b) }
func BenchmarkIOReadDir10(b *testing.B) { benchmarkIOReadDir(10, root, b) }
func BenchmarkIOReadDir20(b *testing.B) { benchmarkIOReadDir(20, root, b) }
func BenchmarkIOReadDir30(b *testing.B) { benchmarkIOReadDir(30, root, b) }
func BenchmarkIOReadDir40(b *testing.B) { benchmarkIOReadDir(40, root, b) }
func BenchmarkIOReadDir50(b *testing.B) { benchmarkIOReadDir(50, root, b) }

func BenchmarkOSReadDir1(b *testing.B)  { benchmarkOSReadDir(1, root, b) }
func BenchmarkOSReadDir2(b *testing.B)  { benchmarkOSReadDir(2, root, b) }
func BenchmarkOSReadDir3(b *testing.B)  { benchmarkOSReadDir(3, root, b) }
func BenchmarkOSReadDir10(b *testing.B) { benchmarkOSReadDir(10, root, b) }
func BenchmarkOSReadDir20(b *testing.B) { benchmarkOSReadDir(20, root, b) }
func BenchmarkOSReadDir30(b *testing.B) { benchmarkOSReadDir(30, root, b) }
func BenchmarkOSReadDir40(b *testing.B) { benchmarkOSReadDir(40, root, b) }
func BenchmarkOSReadDir50(b *testing.B) { benchmarkOSReadDir(50, root, b) }

func benchmarkFilePathWalkDir(i int, root string, b *testing.B) {
	// run the FilePathWalkDir function b.N times
	for n := 0; n < b.N; n++ {
		FpW(i, root)
	}
}

func benchmarkIOReadDir(i int, root string, b *testing.B) {
	// run the IOReadDir function b.N times
	for n := 0; n < b.N; n++ {
		IoRdir(i, root)
	}
}

func benchmarkOSReadDir(i int, root string, b *testing.B) {
	// run the OSReadDir function b.N times
	for n := 0; n < b.N; n++ {
		OsRdir(i, root)
	}
}