dirdump.go

package main

import (
        "bufio"
        "fmt"
        "io/ioutil"
        "os"
        "sort"
        "syscall"
)

type byInode []os.FileInfo

func (this byInode) Len() int { return len(this) }
func (this byInode) Less(i, j int) bool {
        fstat_i := this[i].Sys().(*syscall.Stat_t)
        fstat_j := this[j].Sys().(*syscall.Stat_t)
        return fstat_i.Ino < fstat_j.Ino
}
func (this byInode) Swap(i, j int) { this[i], this[j] = this[j], this[i] }

func MyReadDir(dirname string) ([]os.FileInfo, error) {
        f, err := os.Open(dirname)
        if err != nil {
                return nil, err
        }
        list, err := f.Readdir(-1)
        f.Close()
        if err != nil {
                return nil, err
        }
        return list, nil
}

func MyReadDirSortByInode(dirname string) ([]os.FileInfo, error) {
        f, err := os.Open(dirname)
        if err != nil {
                return nil, err
        }
        list, err := f.Readdir(-1)
        f.Close()
        if err != nil {
                return nil, err
        }
        sort.Sort(byInode(list))
        return list, nil
}

func countLines(file string) (int, error) {
        var err error
        fp, err := os.Open(file)
        if err != nil {
                return -1, err
        }
        defer fp.Close()
        scanner := bufio.NewScanner(fp)
        cnt := 0
        for scanner.Scan() {
                cnt += 1
        }
        if err = scanner.Err(); err != nil {
                return -1, err
        }
        return cnt, err
}

func main() {
        var cnt int = 0
        var numFiles int = 0
        par := os.Args[1]
        switch os.Args[2] {
        case "1":
                fileinfos, _ := MyReadDirSortByInode(par)
                for _, fi := range fileinfos {
                        name := fmt.Sprintf("%s/%s", par, fi.Name())
                        c, err := countLines(name)
                        if err != nil {
                                panic(err)
                        }
                        cnt += c
                        numFiles += 1
                }
        case "2":
                fileinfos, _ := MyReadDir(par)
                for _, fi := range fileinfos {
                        name := fmt.Sprintf("%s/%s", par, fi.Name())
                        c, err := countLines(name)
                        if err != nil {
                                panic(err)
                        }
                        cnt += c
                        numFiles += 1
                }
        case "3":
                fileinfos, _ := ioutil.ReadDir(par)
                for _, fi := range fileinfos {
                        name := fmt.Sprintf("%s/%s", par, fi.Name())
                        c, err := countLines(name)
                        if err != nil {
                                panic(err)
                        }
                        cnt += c
                        numFiles += 1
                }
        }
        fmt.Println(os.Args[1], "num files", numFiles, "num lines", cnt)
}