Move from fmt.Errorf to errors.New

In many cases fmt.Errorf is good enough, but since
error is an interface, you can use arbitrary data
structures as error values, to allow callers to
inspect the details of the error.

pkg/api/minioapi/range.go

@@ -17,6 +17,7 @@
 package minioapi
 
 import (
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -58,28 +59,28 @@ func newRange(req *http.Request, size int64) (*httpRange, error) {
 // parseRange parses a Range header string as per RFC 2616.
 func (r *httpRange) parseRange(s string) error {
 	if s == "" {
-		return fmt.Errorf("header not present")
+		return errors.New("header not present")
 	}
 	if !strings.HasPrefix(s, b) {
-		return fmt.Errorf("invalid range")
+		return errors.New("invalid range")
 	}
 
 	ras := strings.Split(s[len(b):], ",")
 	if len(ras) == 0 {
-		return fmt.Errorf("invalid request")
+		return errors.New("invalid request")
 	}
 	// Just pick the first one and ignore the rest, we only support one range per object
 	if len(ras) > 1 {
-		return fmt.Errorf("multiple ranges specified")
+		return errors.New("multiple ranges specified")
 	}
 
 	ra := strings.TrimSpace(ras[0])
 	if ra == "" {
-		return fmt.Errorf("invalid range")
+		return errors.New("invalid range")
 	}
 	i := strings.Index(ra, "-")
 	if i < 0 {
-		return fmt.Errorf("invalid range")
+		return errors.New("invalid range")
 	}
 	start, end := strings.TrimSpace(ra[:i]), strings.TrimSpace(ra[i+1:])
 	if start == "" {
@@ -87,7 +88,7 @@ func (r *httpRange) parseRange(s string) error {
 		// range start relative to the end of the file.
 		i, err := strconv.ParseInt(end, 10, 64)
 		if err != nil {
-			return fmt.Errorf("invalid range")
+			return errors.New("invalid range")
 		}
 		if i > r.size {
 			i = r.size
@@ -97,7 +98,7 @@ func (r *httpRange) parseRange(s string) error {
 	} else {
 		i, err := strconv.ParseInt(start, 10, 64)
 		if err != nil || i > r.size || i < 0 {
-			return fmt.Errorf("invalid range")
+			return errors.New("invalid range")
 		}
 		r.start = i
 		if end == "" {
@@ -106,7 +107,7 @@ func (r *httpRange) parseRange(s string) error {
 		} else {
 			i, err := strconv.ParseInt(end, 10, 64)
 			if err != nil || r.start > i {
-				return fmt.Errorf("invalid range")
+				return errors.New("invalid range")
 			}
 			if i >= r.size {
 				i = r.size - 1