Added EditRepository function

Author: cmaglie

repos.go

@@ -242,6 +242,50 @@ func RemoveRepository(repo *Repository, configFolderPath string) error {
 	return nil
 }
 
+// EditRepository replace the an old repo configuration with a new repo
+// configuration found in the specified APT config folder (usually /etc/apt).
+func EditRepository(old *Repository, new *Repository, configFolderPath string) error {
+	// Read all repos configurations
+	repos, err := ParseAPTConfigFolder(configFolderPath)
+	if err != nil {
+		return fmt.Errorf("parsing APT config: %s", err)
+	}
+
+	// Find the repo to edit
+	repoToEdit := repos.Find(old)
+	if repoToEdit == nil {
+		return fmt.Errorf("Repository doesn't exist")
+	}
+
+	// Read the config file that contains the repo configuration to edit
+	fileToEdit := repoToEdit.configFile
+	data, err := ioutil.ReadFile(fileToEdit)
+	if err != nil {
+		return fmt.Errorf("Reading config file %s: %s", fileToEdit, err)
+	}
+
+	// Create the new version of the file
+	scanner := bufio.NewScanner(bytes.NewReader(data))
+	newContent := ""
+	for scanner.Scan() {
+		line := scanner.Text()
+		r := parseAPTConfigLine(line)
+		if r.Equals(old) {
+			// Write the new config to replace the old one
+			newContent += new.APTConfigLine() + "\n"
+			continue
+		}
+		newContent += line + "\n"
+	}
+
+	err = replaceFile(fileToEdit, []byte(newContent))
+	if err != nil {
+		return fmt.Errorf("Writing of new config: %s", err)
+	}
+
+	return nil
+}
+
 func replaceFile(path string, newContent []byte) error {
 	newPath := path + ".new"
 	backupPath := path + ".save"

repos_test.go

@@ -95,4 +95,28 @@ func TestAddAndRemoveRepository(t *testing.T) {
 
 	err = RemoveRepository(repo2, "testdata/apt2")
 	require.Error(t, err, "Removing repository again")
+
+	// no changes should have happened
+	repos, err = ParseAPTConfigFolder("testdata/apt2")
+	require.NoError(t, err, "running List command")
+	require.True(t, repos.Contains(repo1), "Configuration contains: %#v", repo1)
+	require.False(t, repos.Contains(repo2), "Configuration contains: %#v", repo2)
+
+	err = EditRepository(repo1, repo2, "testdata/apt2")
+	require.NoError(t, err, "editing repository %#V -> %#V", repo1, repo2)
+
+	// repo2 should be changed to repo1
+	repos, err = ParseAPTConfigFolder("testdata/apt2")
+	require.NoError(t, err, "running List command")
+	require.False(t, repos.Contains(repo1), "Configuration contains: %#v", repo1)
+	require.True(t, repos.Contains(repo2), "Configuration contains: %#v", repo2)
+
+	err = EditRepository(repo1, repo2, "testdata/apt2")
+	require.Error(t, err, "editing again repository %#v -> %#v", repo1, repo2)
+
+	// no changes should have happened
+	repos, err = ParseAPTConfigFolder("testdata/apt2")
+	require.NoError(t, err, "running List command")
+	require.False(t, repos.Contains(repo1), "Configuration contains: %#v", repo1)
+	require.True(t, repos.Contains(repo2), "Configuration contains: %#v", repo2)
 }