Move atomic file writes into its own package, use them inside quick and disk packages

pkg/donut/disk/disk.go

@@ -18,7 +18,6 @@ package disk
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -27,6 +26,7 @@ import (
 	"syscall"
 
 	"github.com/minio/minio/pkg/iodine"
+	"github.com/minio/minio/pkg/utils/atomic"
 )
 
 // Disk container for disk parameters
@@ -36,36 +36,6 @@ type Disk struct {
 	fsInfo map[string]string
 }
 
-// File container provided by disk for atomic file writes
-type File struct {
-	*os.File
-	path string
-}
-
-// Close the file replacing the configured file.
-func (f *File) Close() error {
-	if err := f.File.Close(); err != nil {
-		return err
-	}
-	if err := os.Rename(f.Name(), f.path); err != nil {
-		return err
-	}
-	return nil
-}
-
-// Abort closes the file and removes it instead of replacing the configured
-// file. This is useful if after starting to write to the file you decide you
-// don't want it anymore.
-func (f *File) Abort() error {
-	if err := f.File.Close(); err != nil {
-		return err
-	}
-	if err := os.Remove(f.Name()); err != nil {
-		return err
-	}
-	return nil
-}
-
 // New - instantiate new disk
 func New(diskPath string) (Disk, error) {
 	if diskPath == "" {
@@ -175,7 +145,7 @@ func (disk Disk) ListFiles(dirname string) ([]os.FileInfo, error) {
 }
 
 // CreateFile - create a file inside disk root path, replies with custome disk.File which provides atomic writes
-func (disk Disk) CreateFile(filename string) (*File, error) {
+func (disk Disk) CreateFile(filename string) (*atomic.File, error) {
 	disk.lock.Lock()
 	defer disk.lock.Unlock()
 
@@ -188,16 +158,13 @@ func (disk Disk) CreateFile(filename string) (*File, error) {
 	if err := os.MkdirAll(filepath.Dir(filePath), 0700); err != nil {
 		return nil, iodine.New(err, nil)
 	}
-	f, err := ioutil.TempFile(filepath.Dir(filePath), filepath.Base(filePath))
+
+	f, err := atomic.FileCreate(filePath)
 	if err != nil {
 		return nil, iodine.New(err, nil)
 	}
-	if err := os.Chmod(f.Name(), 0600); err != nil {
-		os.Remove(f.Name())
-		return nil, iodine.New(err, nil)
-	}
 
-	return &File{File: f, path: filePath}, nil
+	return f, nil
 }
 
 // OpenFile - read a file inside disk root path