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// Copyright (C) 2014 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package main
import (
"crypto/sha256"
"errors"
"flag"
"fmt"
"io"
"log"
"os"
"path/filepath"
_ "github.com/syncthing/syncthing/lib/automaxprocs"
)
func main() {
flag.Parse()
log.Println(compareDirectories(flag.Args()...))
}
// Compare a number of directories. Returns nil if the contents are identical,
// otherwise an error describing the first found difference.
func compareDirectories(dirs ...string) error {
chans := make([]chan fileInfo, len(dirs))
for i := range chans {
chans[i] = make(chan fileInfo)
}
errcs := make([]chan error, len(dirs))
abort := make(chan struct{})
for i := range dirs {
errcs[i] = startWalker(dirs[i], chans[i], abort)
}
res := make([]fileInfo, len(dirs))
for {
numDone := 0
for i := range chans {
fi, ok := <-chans[i]
if !ok {
err, hasError := <-errcs[i]
if hasError {
close(abort)
return err
}
numDone++
}
res[i] = fi
}
for i := 1; i < len(res); i++ {
if res[i] != res[0] {
close(abort)
if res[i].name < res[0].name {
return fmt.Errorf("%s missing %v (present in %s)", dirs[0], res[i], dirs[i])
} else if res[i].name > res[0].name {
return fmt.Errorf("%s missing %v (present in %s)", dirs[i], res[0], dirs[0])
}
return fmt.Errorf("mismatch; %v (%s) != %v (%s)", res[i], dirs[i], res[0], dirs[0])
}
}
if numDone == len(dirs) {
return nil
}
}
}
type fileInfo struct {
name string
mode os.FileMode
mod int64
hash [sha256.Size]byte
}
func (f fileInfo) String() string {
return fmt.Sprintf("%s %04o %d %x", f.name, f.mode, f.mod, f.hash)
}
func startWalker(dir string, res chan<- fileInfo, abort <-chan struct{}) chan error {
walker := func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
rn, _ := filepath.Rel(dir, path)
if rn == "." {
return nil
}
if rn == ".stversions" || rn == ".stfolder" {
return filepath.SkipDir
}
var f fileInfo
if info.Mode()&os.ModeSymlink != 0 {
f = fileInfo{
name: rn,
mode: os.ModeSymlink,
}
tgt, err := os.Readlink(path)
if err != nil {
return err
}
f.hash = sha256.Sum256([]byte(tgt))
} else if info.IsDir() {
f = fileInfo{
name: rn,
mode: info.Mode(),
// hash and modtime zero for directories
}
} else {
f = fileInfo{
name: rn,
mode: info.Mode(),
mod: info.ModTime().Unix(),
}
sum, err := sha256file(path)
if err != nil {
return err
}
f.hash = sum
}
select {
case res <- f:
return nil
case <-abort:
return errors.New("abort")
}
}
errc := make(chan error)
go func() {
err := filepath.Walk(dir, walker)
close(res)
if err != nil {
errc <- err
}
close(errc)
}()
return errc
}
func sha256file(fname string) (hash [sha256.Size]byte, err error) {
f, err := os.Open(fname)
if err != nil {
return
}
defer f.Close()
h := sha256.New()
io.Copy(h, f)
hb := h.Sum(nil)
copy(hash[:], hb)
return
}
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