3 files changed, 61 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a5d049c..e256fc6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,8 @@ SPDX-License-Identifier: MIT
   - Add the `force_take` function that ignores a `PoisonError` when accessing
     the manager instance.
 - Internally refactor the `device` module into submodules.
+- Refactor authentication:
+  - Add `AuthenticationError`.
 
 # v0.3.4 (2019-01-20)
 - Fix authentication methods that assumed that `char` is signed.
diff --git a/src/error.rs b/src/error.rs
index 9e6adc0..1b0edd4 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -3,6 +3,7 @@
 
 use std::error;
 use std::fmt;
+use std::marker;
 use std::os::raw;
 use std::str;
 use std::sync;
@@ -46,6 +47,12 @@ impl From<raw::c_int> for Error {
     }
 }
 
+impl<'a, T: crate::Device<'a>> From<AuthenticationError<'a, T>> for Error {
+    fn from(err: AuthenticationError<'a, T>) -> Self {
+        err.error
+    }
+}
+
 impl From<CommandError> for Error {
     fn from(err: CommandError) -> Self {
         Error::CommandError(err)
@@ -267,3 +274,52 @@ impl fmt::Display for LibraryError {
         })
     }
 }
+
+#[derive(Debug)]
+pub struct AuthenticationError<'a, T: device::Device<'a>> {
+    error: Error,
+    device: T,
+    marker: marker::PhantomData<dyn device::Device<'a>>,
+}
+
+impl<'a, T: device::Device<'a>> AuthenticationError<'a, T> {
+    pub fn new(error: Error, device: T) -> Self {
+        AuthenticationError {
+            error,
+            device,
+            marker: marker::PhantomData,
+        }
+    }
+
+    pub fn as_error(&self) -> &Error {
+        &self.error
+    }
+
+    pub fn into_device(self) -> T {
+        self.device
+    }
+
+    pub fn map_device<'b, U, F>(self, op: F) -> AuthenticationError<'b, U>
+    where
+        U: device::Device<'b>,
+        F: Fn(T) -> U,
+    {
+        AuthenticationError {
+            error: self.error,
+            device: op(self.device),
+            marker: marker::PhantomData,
+        }
+    }
+}
+
+impl<'a, T: device::Device<'a>> error::Error for AuthenticationError<'a, T> {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        Some(&self.error)
+    }
+}
+
+impl<'a, T: device::Device<'a>> fmt::Display for AuthenticationError<'a, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.error.fmt(f)
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index a4402c5..e3a2bc3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -121,7 +121,9 @@ pub use crate::device::{
     Device, DeviceWrapper, Model, Pro, SdCardData, Storage, StorageProductionInfo, StorageStatus,
     VolumeMode, VolumeStatus,
 };
-pub use crate::error::{CommandError, CommunicationError, Error, LibraryError};
+pub use crate::error::{
+    AuthenticationError, CommandError, CommunicationError, Error, LibraryError,
+};
 pub use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData};
 pub use crate::pws::{GetPasswordSafe, PasswordSafe, SLOT_COUNT};
 pub use crate::util::LogLevel;