Remove sync::PoisonError from Error::PoisonError

Previously, the Error::PoisonError contained the sync::PoisonError that
caused the error.  This is problematic as sync::PoisonError does not
implement Send, making it impossible to use the Error enum with the
anyhow crate.  At the same time, storing the sync::PoisonError is not
very useful.  If a user wants to access the poisoned lock, they can call
the force_take function.

Therefore we remove the sync::PoisonError value from the Error::
PoisonError variant.  This also allows us to simplify the
From<sync::PoisonError<…>> and From<sync::TryLockError<…>>
implementations as we no longer need to know the type of the mutex that
caused the error.

For more information, see this thread:
	https://lists.sr.ht/~ireas/nitrokey-rs-dev/%3C68ed0f3f-d98f-63bc-04d2-81b6d6cde560%40posteo.net%3E

1 files changed, 4 insertions, 7 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 3fa3ae3..5b72d63 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -470,13 +470,10 @@ pub fn take() -> Result<sync::MutexGuard<'static, Manager>, Error> {
 /// [`ConcurrentAccessError`]: struct.Error.html#variant.ConcurrentAccessError
 /// [`Manager`]: struct.Manager.html
 pub fn force_take() -> Result<sync::MutexGuard<'static, Manager>, Error> {
-    match take() {
-        Ok(guard) => Ok(guard),
-        Err(err) => match err {
-            Error::PoisonError(err) => Ok(err.into_inner()),
-            err => Err(err),
-        },
-    }
+    MANAGER.try_lock().or_else(|err| match err {
+        sync::TryLockError::Poisoned(err) => Ok(err.into_inner()),
+        sync::TryLockError::WouldBlock => Err(Error::ConcurrentAccessError),
+    })
 }
 
 /// List all connected Nitrokey devices.