rust/utils: Add functions to combine I/O arguments

Add functions to properly parse required and optional input/output
parameters that have to be combined into one.

Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

rust/utils/src/cli.rs

@@ -276,6 +276,29 @@ impl DeprecatedVerbosityOptions {
         )
     }
 }
+pub fn combined_path_opt<'a, N: AsRef<str>, P: AsRef<str>>(
+    named: &'a Option<N>,
+    positional: &'a Option<P>,
+    default: &'a str,
+) -> &'a str {
+    match (named, positional) {
+        (None, Some(i)) => i.as_ref(),
+        (Some(i), None) => i.as_ref(),
+        (Some(_), Some(_)) => unreachable!(),
+        (None, None) => default,
+    }
+}
+pub fn combined_path_req<'a, N: AsRef<str>, P: AsRef<str>>(
+    named: &'a Option<N>,
+    positional: &'a Option<P>,
+) -> &'a str {
+    match (named, positional) {
+        (None, Some(i)) => i.as_ref(),
+        (Some(i), None) => i.as_ref(),
+        (Some(_), Some(_)) => unreachable!(),
+        (None, None) => unreachable!(),
+    }
+}
 
 #[cfg(test)]
 mod test {

rust/utils/src/lib.rs

@@ -16,8 +16,9 @@ pub use ::log::LevelFilter;
 
 pub use crate::{
     cli::{
-        get_reader_from_cli_file_arg, get_writer_from_cli_file_arg, print_cli_error, print_error,
+        combined_path_opt, combined_path_req, get_reader_from_cli_file_arg,
-        CertificateOptions, DeprecatedVerbosityOptions, VerbosityOptions, STDIN, STDOUT,
+        get_writer_from_cli_file_arg, print_cli_error, print_error, CertificateOptions,
+        DeprecatedVerbosityOptions, VerbosityOptions, STDIN, STDOUT,
     },
     exit_code::{docstring, ExitCodeDoc, ExitCodeTrait, ExitCodeVariantDoc},
     file::{AtomicFile, AtomicFileOperation},