Move the CommandError::Unknown to Error

An error code can not only indiciate a command error, but also a library
or device communication error.  Therefore, the variant for an unknown
error code should be placed in the top-level Error enum instead of the
CommandError enum.

5 files changed, 40 insertions, 32 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5a78724..def5273 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,8 @@
   - Implement `std::error::Error` for `CommandError`.
   - Add the `Error` enum and the `Result` typedef.
   - Return `Error` instead of `CommandError` in all public functions.
-  - Move the `CommandError::RngError` variant to `Error::RandError`.
+  - Move the `CommandError::RngError` variant to `Error::RandError` and the
+    `CommandError::Unknown` variant to `Error::Unknown`.
 
 # v0.3.4 (2019-01-20)
 - Fix authentication methods that assumed that `char` is signed.
diff --git a/src/auth.rs b/src/auth.rs
index 509d3aa..e05f6b3 100644
--- a/src/auth.rs
+++ b/src/auth.rs
@@ -6,7 +6,7 @@ use nitrokey_sys;
 
 use crate::config::{Config, RawConfig};
 use crate::device::{Device, DeviceWrapper, Pro, Storage};
-use crate::error::{CommandError, Error};
+use crate::error::Error;
 use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData, RawOtpSlotData};
 use crate::util::{generate_password, get_command_result, get_cstring, result_from_string};
 
@@ -161,7 +161,7 @@ where
     let temp_password_ptr = temp_password.as_ptr() as *const c_char;
     return match callback(password_ptr, temp_password_ptr) {
         0 => Ok(A::new(device, temp_password)),
-        rv => Err((device, CommandError::from(rv).into())),
+        rv => Err((device, Error::from(rv))),
     };
 }
 
diff --git a/src/error.rs b/src/error.rs
index dfe1680..c5a975e 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -13,6 +13,18 @@ pub enum Error {
     CommunicationError(CommunicationError),
     /// An error that occured during random number generation.
     RandError(rand_core::Error),
+    /// An unknown error returned by libnitrokey.
+    Unknown(i64),
+}
+
+impl From<raw::c_int> for Error {
+    fn from(code: raw::c_int) -> Self {
+        if let Some(err) = CommandError::try_from(code) {
+            Error::CommandError(err)
+        } else {
+            Error::Unknown(code.into())
+        }
+    }
 }
 
 impl From<CommandError> for Error {
@@ -33,6 +45,7 @@ impl error::Error for Error {
             Error::CommandError(ref err) => Some(err),
             Error::CommunicationError(_) => None,
             Error::RandError(ref err) => Some(err),
+            Error::Unknown(_) => None,
         }
     }
 }
@@ -43,6 +56,7 @@ impl fmt::Display for Error {
             Error::CommandError(ref err) => write!(f, "Command error: {}", err),
             Error::CommunicationError(_) => write!(f, "Placeholder"),
             Error::RandError(ref err) => write!(f, "RNG error: {}", err),
+            Error::Unknown(ref err) => write!(f, "Unknown error: {}", err),
         }
     }
 }
@@ -74,8 +88,6 @@ pub enum CommandError {
     UnknownCommand,
     /// AES decryption failed.
     AesDecryptionFailed,
-    /// An unknown error occurred.
-    Unknown(i64),
     /// An unspecified error occurred.
     Undefined,
     /// You passed a string containing a null byte.
@@ -98,6 +110,26 @@ pub enum CommunicationError {
 }
 
 impl CommandError {
+    fn try_from(value: raw::c_int) -> Option<Self> {
+        match value {
+            1 => Some(CommandError::WrongCrc),
+            2 => Some(CommandError::WrongSlot),
+            3 => Some(CommandError::SlotNotProgrammed),
+            4 => Some(CommandError::WrongPassword),
+            5 => Some(CommandError::NotAuthorized),
+            6 => Some(CommandError::Timestamp),
+            7 => Some(CommandError::NoName),
+            8 => Some(CommandError::NotSupported),
+            9 => Some(CommandError::UnknownCommand),
+            10 => Some(CommandError::AesDecryptionFailed),
+            200 => Some(CommandError::StringTooLong),
+            201 => Some(CommandError::InvalidSlot),
+            202 => Some(CommandError::InvalidHexString),
+            203 => Some(CommandError::TargetBufferTooSmall),
+            _ => None,
+        }
+    }
+
     fn as_str(&self) -> borrow::Cow<'static, str> {
         match *self {
             CommandError::WrongCrc => {
@@ -116,9 +148,6 @@ impl CommandError {
             CommandError::NotSupported => "This command is not supported by this device".into(),
             CommandError::UnknownCommand => "This command is unknown".into(),
             CommandError::AesDecryptionFailed => "AES decryption failed".into(),
-            CommandError::Unknown(x) => {
-                borrow::Cow::from(format!("An unknown error occurred ({})", x))
-            }
             CommandError::Undefined => "An unspecified error occurred".into(),
             CommandError::InvalidString => "You passed a string containing a null byte".into(),
             CommandError::StringTooLong => "The supplied string is too long".into(),
@@ -138,25 +167,3 @@ impl fmt::Display for CommandError {
         write!(f, "{}", self.as_str())
     }
 }
-
-impl From<raw::c_int> for CommandError {
-    fn from(value: raw::c_int) -> Self {
-        match value {
-            1 => CommandError::WrongCrc,
-            2 => CommandError::WrongSlot,
-            3 => CommandError::SlotNotProgrammed,
-            4 => CommandError::WrongPassword,
-            5 => CommandError::NotAuthorized,
-            6 => CommandError::Timestamp,
-            7 => CommandError::NoName,
-            8 => CommandError::NotSupported,
-            9 => CommandError::UnknownCommand,
-            10 => CommandError::AesDecryptionFailed,
-            200 => CommandError::StringTooLong,
-            201 => CommandError::InvalidSlot,
-            202 => CommandError::InvalidHexString,
-            203 => CommandError::TargetBufferTooSmall,
-            x => CommandError::Unknown(x.into()),
-        }
-    }
-}
diff --git a/src/util.rs b/src/util.rs
index 06bb854..3b9904f 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -54,7 +54,7 @@ pub fn result_from_string(ptr: *const c_char) -> Result<String, Error> {
 pub fn get_command_result(value: c_int) -> Result<(), Error> {
     match value {
         0 => Ok(()),
-        other => Err(CommandError::from(other).into()),
+        other => Err(Error::from(other)),
     }
 }
 
diff --git a/tests/pws.rs b/tests/pws.rs
index f12af48..a4647bd 100644
--- a/tests/pws.rs
+++ b/tests/pws.rs
@@ -21,7 +21,7 @@ fn get_slot_name_direct(slot: u8) -> Result<String, Error> {
             let error = unsafe { nitrokey_sys::NK_get_last_command_status() } as c_int;
             match error {
                 0 => Ok(s),
-                other => Err(CommandError::from(other).into()),
+                other => Err(Error::from(other)),
             }
         }
         false => Ok(s),