Explorations in Go: A dupe checker in Go and Ruby

argument-parsing-nice

➜  dupe git:(master) ✗ ./dupe --help
Usage of ./dupe:
  -verbose=false: Print the list of duplicate files.

argument-parsing.go

var verbose *bool = flag.Bool("verbose", false, "Print the list of duplicate files.")
	
var rootDir string = "."

func ParseArgs() {
  flag.Parse()
  if (len(flag.Args()) > 0) { 
    rootDir = flag.Arg(0)
  } 
}

argument-parsing.rb

VERBOSE = ARGV.delete('--verbose')
ROOT_DIR = ARGV[0] ||= "."

filesystem-traversal-1.go

var fullPathsByFilename map[string][]string

type DupeChecker struct{}

func (dc DupeChecker) VisitDir(fullpath string, f *os.FileInfo) bool {
  return true
}

func (dc DupeChecker) VisitFile(fullpath string, f *os.FileInfo) {
  filename := path.Base(fullpath)
  fullPathsByFilename[filename] = append(fullPathsByFilename[filename], fullpath)
}

func FindDupes(root string) {
  fullPathsByFilename = make(map[string][]string)
  filepath.Walk(root, DupeChecker{}, nil)
}

filesystem-traversal-2.go

func Walk(root string, v Visitor, errors chan<- os Error)

filesystem-traversal-3.go

type Visitor interface {
    VisitDir(path string, f *os.FileInfo) bool
    VisitFile(path string, f *os.FileInfo)
}

filesystem-traversal.rb

@full_paths_by_filename = {}

def visit_file(fullpath)
  return if File.directory? fullpath
  return if File.symlink? fullpath
  basename = File.basename(fullpath)
  (@full_paths_by_filename[basename] ||= []) << fullpath
end

Find.find(ROOT_DIR) do |fullpath|
  visit_file(fullpath)
end

md5.go

func MD5OfFile(fullpath string) []byte {
  if contents, err := ioutil.ReadFile(fullpath); err == nil { 
    var md5sum hash.Hash = md5.New()
    md5sum.Write(contents)
    return md5sum.Sum()
  }
  return nil
}

md5.rb

def md5_of_file(fullpath)
  Digest::MD5.hexdigest(File.read(fullpath))
end

posix.c

fd = socket(PF_UNIX, SOCK_STREAM, 0);
if (fd == -1)
	return errno;