Move the code for Fedora support into its own file

This will reduce the size of the src/pkg/utils/utils.go file and make it
easier to specify which part of the code base is maintained by whom.

https://github.com/containers/toolbox/pull/1639

src/meson.build

@@ -33,6 +33,7 @@ sources = files(
   'pkg/utils/libsubid-wrappers.c',
   'pkg/utils/arch.go',
   'pkg/utils/errors.go',
+  'pkg/utils/fedora.go',
   'pkg/utils/utils.go',
   'pkg/utils/utils_cgo.go',
   'pkg/utils/utils_test.go',

src/pkg/utils/fedora.go

@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2021 – 2025 Red Hat Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package utils
+
+import (
+	"strconv"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+)
+
+func getDefaultReleaseFedora() (string, error) {
+	release, err := getHostVersionID()
+	if err != nil {
+		return "", err
+	}
+
+	return release, nil
+}
+
+func getFullyQualifiedImageFedora(image, release string) string {
+	imageFull := "registry.fedoraproject.org/" + image
+	return imageFull
+}
+
+func parseReleaseFedora(release string) (string, error) {
+	if strings.HasPrefix(release, "F") || strings.HasPrefix(release, "f") {
+		release = release[1:]
+	}
+
+	releaseN, err := strconv.Atoi(release)
+	if err != nil {
+		logrus.Debugf("Parsing release %s as an integer failed: %s", release, err)
+		return "", &ParseReleaseError{"The release must be a positive integer."}
+	}
+
+	if releaseN <= 0 {
+		return "", &ParseReleaseError{"The release must be a positive integer."}
+	}
+
+	return release, nil
+}

src/pkg/utils/utils.go

@@ -328,15 +328,6 @@ func getDefaultReleaseForDistro(distro string) (string, error) {
 	return release, nil
 }
 
-func getDefaultReleaseFedora() (string, error) {
-	release, err := getHostVersionID()
-	if err != nil {
-		return "", err
-	}
-
-	return release, nil
-}
-
 func getDefaultReleaseRHEL() (string, error) {
 	release, err := getHostVersionID()
 	if err != nil {
@@ -415,11 +406,6 @@ func GetFullyQualifiedImageFromDistros(image, release string) (string, error) {
 	return "", fmt.Errorf("failed to resolve image %s", image)
 }
 
-func getFullyQualifiedImageFedora(image, release string) string {
-	imageFull := "registry.fedoraproject.org/" + image
-	return imageFull
-}
-
 func getFullyQualifiedImageRHEL(image, release string) string {
 	i := strings.IndexRune(release, '.')
 	if i == -1 {
@@ -747,24 +733,6 @@ func parseRelease(distro, release string) (string, error) {
 	return release, err
 }
 
-func parseReleaseFedora(release string) (string, error) {
-	if strings.HasPrefix(release, "F") || strings.HasPrefix(release, "f") {
-		release = release[1:]
-	}
-
-	releaseN, err := strconv.Atoi(release)
-	if err != nil {
-		logrus.Debugf("Parsing release %s as an integer failed: %s", release, err)
-		return "", &ParseReleaseError{"The release must be a positive integer."}
-	}
-
-	if releaseN <= 0 {
-		return "", &ParseReleaseError{"The release must be a positive integer."}
-	}
-
-	return release, nil
-}
-
 func parseReleaseRHEL(release string) (string, error) {
 	if i := strings.IndexRune(release, '.'); i == -1 {
 		return "", &ParseReleaseError{"The release must be in the '<major>.<minor>' format."}