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// Copyright 2017 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// md5sum replicates the equivalent functionality of the unix tool of the same name.
package main
import (
"crypto/md5"
"flag"
"fmt"
"io"
"log"
"os"
"path/filepath"
)
func md5SumFile(filename string) ([]byte, error) {
var result []byte
f, err := os.Open(filename)
if err != nil {
return result, err
}
defer f.Close()
hash := md5.New()
if _, err := io.Copy(hash, f); err != nil {
return nil, err
}
return hash.Sum(result), nil
}
func run(args []string) error {
// Prepare our flags
flags := flag.NewFlagSet("md5sum", flag.ExitOnError)
output := flags.String("output", "", "If set, write the results to this file, instead of stdout.")
if err := flags.Parse(args); err != nil {
return err
}
// print the outputs if we need not
to := os.Stdout
if *output != "" {
f, err := os.Create(*output)
if err != nil {
return err
}
defer f.Close()
to = f
}
for _, path := range flags.Args() {
walkFn := func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
return nil
}
if b, err := md5SumFile(path); err != nil {
return err
} else {
fmt.Fprintf(to, "%s %x\n", path, b)
}
return nil
}
if err := filepath.Walk(path, walkFn); err != nil {
return err
}
}
return nil
}
func main() {
log.SetFlags(0)
log.SetPrefix("GoMd5sum: ")
if err := run(os.Args[1:]); err != nil {
log.Fatal(err)
}
}
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