GoHash/GoHash.go

package main

import (
	"bufio"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"runtime"
	"sync"
	"time"

	"code.cloudfoundry.org/bytefmt"

	flag "github.com/spf13/pflag"
)

// Fdhashes struct for holding all informations about one folder.
type Fdhashes struct {
	Path   string
	Hashes map[string]string
	Times  map[string]time.Time
	Dirty  bool
}

var hashes map[string]Fdhashes

var wg sync.WaitGroup
var mu sync.RWMutex
var driveLetter string

var rewrite bool
var compare bool

func init() {
	flag.BoolVarP(&rewrite, "rewrite", "r", false, "rewrite all fhhashes files.")
	flag.BoolVarP(&compare, "compare", "c", false, "compare all file hashes and writing a compartion report.")
}

func main() {
	log.Println("starting GoHash")
	runtime.GOMAXPROCS(5)
	hashes = make(map[string]Fdhashes)
	flag.Parse()
	myFile := flag.Arg(0)
	file, err := os.Stat(myFile)
	if os.IsNotExist(err) {
		log.Fatalln("File does not exists:", myFile)
	}
	if file.IsDir() {
		log.Println("start with folder:", myFile)
		driveLetter = ""
		if runtime.GOOS == "windows" {
			driveLetter = filepath.VolumeName(myFile) + "/"
		}
		if compare {
			compareFolder(myFile)
		} else {
			processFolder(myFile)
			fmt.Println("waiting")
			wg.Wait()
			saveAllHashFiles()
		}
	} else {
		log.Printf("file %s has hash %s\n", myFile, getSha256Hash(myFile))
	}

	log.Println("done")
}

func getSha256Hash(fileStr string) string {
	f, err := os.Open(fileStr)
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	h := sha256.New()
	if _, err := io.Copy(h, f); err != nil {
		log.Fatal(err)
	}
	return hex.EncodeToString(h.Sum(nil))
}

var lock1 = sync.RWMutex{}
var lock2 = sync.RWMutex{}

func outputHash(fileStr string) {
	var hashFile Fdhashes
	doHash := true
	defer wg.Done()
	dir, fileName := filepath.Split(fileStr)
	if fileName == ".fdhashes3" {
		return
	}
	// checking if hash is present
	mu.Lock()
	hashFile, ok := hashes[dir]
	if !ok {
		_, err := os.Stat(dir + ".fdhashes3")
		if os.IsNotExist(err) {
			hashFile = Fdhashes{Path: dir, Hashes: make(map[string]string), Times: make(map[string]time.Time), Dirty: true}
		} else {
			hashFile = loadHashfile(dir + ".fdhashes3")
		}
		hashes[dir] = hashFile
	}
	lock1.RLock()
	_, ok = hashFile.Hashes[fileName]
	lock1.RUnlock()
	mu.Unlock()
	doHash = !ok
	// checking if dattime is identically
	file, _ := os.Stat(fileStr)
	time := file.ModTime()
	lock2.RLock()
	savedTime, ok := hashFile.Times[fileName]
	lock2.RUnlock()
	if !time.Equal(savedTime) || !ok {
		doHash = true
	}
	if doHash {
		hash := getSha256Hash(fileStr)
		mu.Lock()
		lock1.Lock()
		hashFile.Hashes[fileName] = hash
		lock1.Unlock()

		lock2.Lock()
		hashFile.Times[fileName] = time
		lock2.Unlock()
		saveHashfile(&hashFile)
		hashes[dir] = hashFile
		mu.Unlock()
		log.Printf("file \"%s\" has hash \"%s\"\n", fileStr, hash)
	}
}

var count int
var addWork int

func processFolder(folder string) {
	count = 0
	addWork = 0
	err := filepath.Walk(folder, func(path string, info os.FileInfo, err error) error {
		count++
		if (count % 100) == 0 {
			fmt.Print(".")
		}
		if (count % 10000) == 0 {
			fmt.Println()
		}
		filename := info.Name()
		if filename[0:1] != "." {
			if info.IsDir() {
				fmt.Println(path)
			}
			if !info.IsDir() {
				addWork++
				wg.Add(1)
				go outputHash(path)
				if addWork > 1000 {
					fmt.Println("x")
					wg.Wait()
					saveAllHashFiles()
					addWork = 0
				}
			}
		}
		return nil
	})
	if err != nil {
		panic(err)
	}
}

func saveHashfile(hashFile *Fdhashes) {
	hashFile.Dirty = true
}

func saveAllHashFiles() {
	hashList := make([]Fdhashes, 0)

	for _, hashFile := range hashes {
		if hashFile.Dirty {
			hashFile.Dirty = false
			b, err := json.Marshal(hashFile)
			if err != nil {
				fmt.Println(err)
				return
			}
			err = ioutil.WriteFile(hashFile.Path+".fdhashes3", b, 0644)
			if err != nil {
				panic(err)
			}
			hashList = append(hashList, hashFile)
		}
	}

	hashes = make(map[string]Fdhashes)
	for _, hashFile := range hashList {
		hashes[hashFile.Path] = hashFile
	}

}

func loadHashfile(fileStr string) Fdhashes {
	dir, _ := filepath.Split(fileStr)
	data := Fdhashes{Path: dir, Hashes: make(map[string]string), Times: make(map[string]time.Time), Dirty: false}
	if !rewrite {
		file, err := ioutil.ReadFile(fileStr)
		if err != nil {
			panic(err)
		}
		err = json.Unmarshal([]byte(file), &data)
		if err != nil {
			log.Printf("can't read file %s", fileStr)
		}
	}
	if data.Path != dir {
		data.Path = dir
		data.Dirty = true
	}
	return data
}

func compareFolder(folder string) {
	loadAllHashFiles(folder)

	index := make(map[string][]string)

	for _, hashFile := range hashes {
		for filename, hash := range hashFile.Hashes {
			values := index[hash]
			if values == nil {
				values = make([]string, 0)
			}
			values = append(values, fmt.Sprintf("%s/%s", hashFile.Path, filename))
			index[hash] = values
		}
	}

	size := len(index)
	f, err := os.Create("report.txt")
	check(err)
	w := bufio.NewWriter(f)
	count := 0
	var filesize int64
	fileCount := 0
	for _, values := range index {
		count++
		if count%100 == 0 {
			fmt.Printf("%d (%d) checking\n", count, size)
		}
		if len(values) > 1 {
			info, err := os.Stat(values[0])
			if err == nil {
				w.WriteString(fmt.Sprintf("found identically hash: size: %d\n", info.Size()))
				filesize += int64(len(values)-1) * info.Size()
			}
			fileCount += len(values) - 1
			for _, filename := range values {
				w.WriteString(fmt.Sprintf("  %s\n", filename))
			}
			w.Flush()
		}
	}
	w.WriteString(fmt.Sprintf("can save up to %s on %d files\n", bytefmt.ByteSize(uint64(filesize)), fileCount))
	w.Flush()
}

func compareFolder2(folder string) {
	loadAllHashFiles(folder)
	size := len(hashes)
	f, err := os.Create("report.txt")
	check(err)
	w := bufio.NewWriter(f)
	count := 0
	for _, hashFile := range hashes {
		count++
		fmt.Printf("%d (%d) checking: %s\n", count, size, hashFile.Path)
		//		fmt.Printf("checking: %s\n", hashFile.Path)
		for filename, hash := range hashFile.Hashes {
			if value, found := search(hash, filename, hashFile.Path); found {
				w.WriteString("found identically hash\n")
				w.WriteString(fmt.Sprintf("  src:  %s/%s\n", hashFile.Path, filename))
				w.WriteString(fmt.Sprintf("  dest: %s\n", value))
				w.Flush()
			}
		}
	}
}

func search(srcHash string, exFilename string, exFilepath string) (value string, found bool) {
	for _, hashFile := range hashes {
		for filename, hash := range hashFile.Hashes {
			if (filename != exFilename) && (hashFile.Path != exFilepath) {
				if hash == srcHash {
					value += fmt.Sprintf("%s/%s;", hashFile.Path, filename)
					found = true
				}
			}
		}
	}
	return
}

func loadAllHashFiles(folder string) {
	count = 0
	addWork = 0
	err := filepath.Walk(folder, func(path string, info os.FileInfo, err error) error {
		//filename := info.Name()
		if info.IsDir() {
			fmt.Print(".")
			hashFile, ok := hashes[path]
			if !ok {
				_, err := os.Stat(path + "/.fdhashes3")
				if os.IsNotExist(err) {
					hashFile = Fdhashes{Path: path, Hashes: make(map[string]string), Times: make(map[string]time.Time), Dirty: true}
				} else {
					hashFile = loadHashfile(path + "/.fdhashes3")
				}
				hashes[path] = hashFile
			}
		}
		return nil
	})
	if err != nil {
		panic(err)
	}
	fmt.Printf("\nfound %d hash files.\n", len(hashes))
}

func check(e error) {
	if e != nil {
		panic(e)
	}
}