Introduce the Error::UnexpectedError variant

The UnexpectedError variant is used when a libnitrokey function returns
a value that violates the function’s contract, for example if a function
returns a null pointer although it guarantees to never return null.
Previously, we returned a CommandError::Unspecified in these cases.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/error.rs b/src/error.rs
index ef9b149..b27124c 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -14,6 +14,8 @@ pub enum Error {
     LibraryError(LibraryError),
     /// An error that occured during random number generation.
     RandError(rand_core::Error),
+    /// An error that is caused by an unexpected value returned by libnitrokey.
+    UnexpectedError,
     /// An unknown error returned by libnitrokey.
     Unknown(i64),
 }
@@ -63,6 +65,7 @@ impl error::Error for Error {
             Error::CommunicationError(ref err) => Some(err),
             Error::LibraryError(ref err) => Some(err),
             Error::RandError(ref err) => Some(err),
+            Error::UnexpectedError => None,
             Error::Unknown(_) => None,
         }
     }
@@ -75,6 +78,7 @@ impl fmt::Display for Error {
             Error::CommunicationError(ref err) => write!(f, "Communication error: {}", err),
             Error::LibraryError(ref err) => write!(f, "Library error: {}", err),
             Error::RandError(ref err) => write!(f, "RNG error: {}", err),
+            Error::UnexpectedError => write!(f, "An unexpected error occurred"),
             Error::Unknown(ref err) => write!(f, "Unknown error: {}", err),
         }
     }