filesystem: split out leading directory creation

Extract leading directory creation into its own private function
('createLeadingDirs()') in 'filesystem.go'. Although 'WriteFile()' is still
the only usage of this functionality, it could prove useful for functions
added to 'fileSystem' in the future.

Signed-off-by: Victoria Dye <[email protected]>

Author: vdye

internal/common/filesystem.go

@@ -31,6 +31,16 @@ func NewFileSystem() FileSystem {
 	return &fileSystem{}
 }
 
+func (f *fileSystem) createLeadingDirs(filename string) error {
+	parentDir := path.Dir(filename)
+	err := os.MkdirAll(parentDir, DefaultDirPermissions)
+	if err != nil {
+		return fmt.Errorf("error creating parent directories: %w", err)
+	}
+
+	return nil
+}
+
 func (f *fileSystem) GetLocalExecutable(name string) (string, error) {
 	thisExePath, err := os.Executable()
 	if err != nil {
@@ -64,11 +74,9 @@ func (f *fileSystem) FileExists(filename string) (bool, error) {
 }
 
 func (f *fileSystem) WriteFile(filename string, content []byte) error {
-	// Get filename parent path
-	parentDir := path.Dir(filename)
-	err := os.MkdirAll(parentDir, DefaultDirPermissions)
+	err := f.createLeadingDirs(filename)
 	if err != nil {
-		return fmt.Errorf("error creating parent directories: %w", err)
+		return err
 	}
 
 	err = os.WriteFile(filename, content, DefaultFilePermissions)