Add checksum and move verifier

cmd/root.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/rpanchyk/fsync/internal/checksum"
 	"github.com/rpanchyk/fsync/internal/service"
-	"github.com/rpanchyk/fsync/internal/verify"
 	"github.com/spf13/cobra"
 )
 
@@ -38,7 +38,7 @@ Attention! Use this tool on your own risk! Author is not responsible of synced f
 			VerboseFlag: verboseFlag,
 			Source:      args[0],
 			Destination: args[1],
-			Verifier:    &verify.MD5Verifier{},
+			Verifier:    checksum.NewVerifier(checksum.MD5),
 		}
 		if err := syncer.Sync(); err != nil {
 			fmt.Println("Sync failed")

internal/checksum/checksum.go

@@ -0,0 +1,12 @@
+package checksum
+
+type CheckSum interface {
+	GetCheckSum(filePath string) (string, error)
+}
+
+type CheckSumType uint8
+
+const (
+	MD5 CheckSumType = iota
+	CRC32
+)

internal/checksum/crc32_checksum.go

@@ -0,0 +1,10 @@
+package checksum
+
+import "errors"
+
+type CRC32CheckSum struct {
+}
+
+func (c CRC32CheckSum) GetCheckSum(filePath string) (string, error) {
+	return "", errors.New("not implemented")
+}

internal/checksum/md5_checksum.go

@@ -0,0 +1,25 @@
+package checksum
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"os"
+)
+
+type MD5CheckSum struct {
+}
+
+func (c MD5CheckSum) GetCheckSum(filePath string) (string, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	hash := md5.New()
+	if _, err := io.Copy(hash, file); err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%x", hash.Sum(nil)), nil
+}

internal/checksum/verifier.go

@@ -0,0 +1,62 @@
+package checksum
+
+import (
+	"sync"
+)
+
+type Verifier struct {
+	checkSum CheckSum
+}
+
+func NewVerifier(checkSumType CheckSumType) *Verifier {
+	verifier := &Verifier{}
+	switch checkSumType {
+	case CRC32:
+		verifier.checkSum = &CRC32CheckSum{}
+	case MD5:
+		fallthrough
+	default:
+		verifier.checkSum = &MD5CheckSum{}
+	}
+	return verifier
+}
+
+func (v Verifier) Same(file1, file2 string) (bool, error) {
+	var wg sync.WaitGroup
+	outChan := make(chan string, 2)
+	errChan := make(chan error, 2)
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		v.getSum(file1, outChan, errChan)
+	}()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		v.getSum(file2, outChan, errChan)
+	}()
+
+	go func() {
+		wg.Wait()
+		close(outChan)
+		close(errChan)
+	}()
+
+	for err := range errChan {
+		return false, err
+	}
+
+	sumA := <-outChan
+	sumB := <-outChan
+	return sumA == sumB, nil
+}
+
+func (v Verifier) getSum(filePath string, outChan chan string, errChan chan error) {
+	if sum, err := v.checkSum.GetCheckSum(filePath); err != nil {
+		errChan <- err
+	} else {
+		outChan <- sum
+	}
+}

internal/service/syncer.go

@@ -7,14 +7,14 @@ import (
 	"path/filepath"
 	"strings"
 
-	"github.com/rpanchyk/fsync/internal/verify"
+	"github.com/rpanchyk/fsync/internal/checksum"
 )
 
 type Syncer struct {
 	VerboseFlag bool
 	Source      string
 	Destination string
-	Verifier    verify.Verifier
+	Verifier    *checksum.Verifier
 
 	// runtime
 	absoluteSourcePath      string