Merge pull request #50 from kolyshkin/go120

modernize with go1.20 features

Author: thaJeztah

size.go

@@ -89,21 +89,16 @@ func RAMInBytes(size string) (int64, error) {
 
 // Parses the human-readable size string into the amount it represents.
 func parseSize(sizeStr string, uMap unitMap) (int64, error) {
-	// TODO: rewrite to use strings.Cut if there's a space
-	// once Go < 1.18 is deprecated.
-	sep := strings.LastIndexAny(sizeStr, "01234567890. ")
-	if sep == -1 {
-		// There should be at least a digit.
-		return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
-	}
-	var num, sfx string
-	if sizeStr[sep] != ' ' {
+	num, sfx, ok := strings.Cut(sizeStr, " ")
+	if !ok {
+		// No space between number and suffix. Find the suffix.
+		sep := strings.LastIndexAny(sizeStr, "01234567890.")
+		if sep == -1 {
+			// There should be at least a digit.
+			return -1, fmt.Errorf("invalid size: '%s'", sizeStr)
+		}
 		num = sizeStr[:sep+1]
 		sfx = sizeStr[sep+1:]
-	} else {
-		// Omit the space separator.
-		num = sizeStr[:sep]
-		sfx = sizeStr[sep+1:]
 	}
 
 	size, err := strconv.ParseFloat(num, 64)

size_test.go

@@ -256,7 +256,7 @@ func BenchmarkParseSize(b *testing.B) {
 	}
 }
 
-func assertEquals(t *testing.T, expected, actual interface{}) {
+func assertEquals(t *testing.T, expected, actual any) {
 	t.Helper()
 	if expected != actual {
 		t.Errorf("Expected '%v' but got '%v'", expected, actual)

ulimit.go

@@ -64,13 +64,13 @@ var ulimitNameMapping = map[string]int{
 
 // ParseUlimit parses and returns a Ulimit from the specified string.
 func ParseUlimit(val string) (*Ulimit, error) {
-	parts := strings.SplitN(val, "=", 2)
-	if len(parts) != 2 {
+	name, val, ok := strings.Cut(val, "=")
+	if !ok {
 		return nil, fmt.Errorf("invalid ulimit argument: %s", val)
 	}
 
-	if _, exists := ulimitNameMapping[parts[0]]; !exists {
-		return nil, fmt.Errorf("invalid ulimit type: %s", parts[0])
+	if _, exists := ulimitNameMapping[name]; !exists {
+		return nil, fmt.Errorf("invalid ulimit type: %s", name)
 	}
 
 	var (
@@ -79,21 +79,19 @@ func ParseUlimit(val string) (*Ulimit, error) {
 		temp int64
 		err  error
 	)
-	switch limitVals := strings.Split(parts[1], ":"); len(limitVals) {
-	case 2:
-		temp, err = strconv.ParseInt(limitVals[1], 10, 64)
+	switch softStr, hardStr, ok := strings.Cut(val, ":"); ok {
+	case true:
+		temp, err = strconv.ParseInt(hardStr, 10, 64)
 		if err != nil {
 			return nil, err
 		}
 		hard = &temp
 		fallthrough
-	case 1:
-		soft, err = strconv.ParseInt(limitVals[0], 10, 64)
+	case false:
+		soft, err = strconv.ParseInt(softStr, 10, 64)
 		if err != nil {
 			return nil, err
 		}
-	default:
-		return nil, fmt.Errorf("too many limit value arguments - %s, can only have up to two, `soft[:hard]`", parts[1])
 	}
 
 	if *hard != -1 {
@@ -105,7 +103,7 @@ func ParseUlimit(val string) (*Ulimit, error) {
 		}
 	}
 
-	return &Ulimit{Name: parts[0], Soft: soft, Hard: *hard}, nil
+	return &Ulimit{Name: name, Soft: soft, Hard: *hard}, nil
 }
 
 // GetRlimit returns the RLimit corresponding to Ulimit.

ulimit_test.go

@@ -51,6 +51,12 @@ func TestParseUlimitBadFormat(t *testing.T) {
 	if _, err := ParseUlimit("nofile=:1024"); err == nil {
 		t.Fatal("expected error on bad syntax")
 	}
+	if _, err := ParseUlimit("nofile=1024=512"); err == nil {
+		t.Fatal("expected error on bad syntax")
+	}
+	if _, err := ParseUlimit("nofile=1024:512=extra"); err == nil {
+		t.Fatal("expected error on bad syntax")
+	}
 }
 
 func TestParseUlimitHardLessThanSoft(t *testing.T) {