| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Ouroboros.Consensus.Util.NormalForm.StrictMVar
Description
StrictMVars with NoThunks invariants.
Custom invariants can still be specified in addition to the default
NoThunks invariant. See newMVarWithInvariant and
newEmptyMVarWithInvariant.
Use the checkmvarinvariants cabal flag from the strict-checked-vars
package to enable or disable invariant checks at compile time.
The exports of this module (should) mirror the exports of the
Control.Concurrent.Class.MonadMVar.Strict.Checked module from the
strict-checked-vars package.
Synopsis
- newEmptyMVar ∷ (MonadMVar m, NoThunks a) ⇒ m (StrictMVar m a)
- newEmptyMVarWithInvariant ∷ (MonadMVar m, NoThunks a) ⇒ (a → Maybe String) → m (StrictMVar m a)
- newMVar ∷ (HasCallStack, MonadMVar m, NoThunks a) ⇒ a → m (StrictMVar m a)
- newMVarWithInvariant ∷ (HasCallStack, MonadMVar m, NoThunks a) ⇒ (a → Maybe String) → a → m (StrictMVar m a)
- noThunksInvariant ∷ NoThunks a ⇒ a → Maybe String
- uncheckedNewEmptyMVar ∷ MonadMVar m ⇒ m (StrictMVar m a)
- uncheckedNewMVar ∷ MonadMVar m ⇒ a → m (StrictMVar m a)
- class Monad m ⇒ MonadMVar (m ∷ Type → Type)
- type LazyMVar (m ∷ Type → Type) = MVar m
- data StrictMVar (m ∷ Type → Type) a
- takeMVar ∷ MonadMVar m ⇒ StrictMVar m a → m a
- readMVar ∷ MonadMVar m ⇒ StrictMVar m a → m a
- putMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m ()
- tryTakeMVar ∷ MonadMVar m ⇒ StrictMVar m a → m (Maybe a)
- tryPutMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m Bool
- tryReadMVar ∷ MonadMVar m ⇒ StrictMVar m a → m (Maybe a)
- isEmptyMVar ∷ MonadMVar m ⇒ StrictMVar m a → m Bool
- withMVar ∷ MonadMVar m ⇒ StrictMVar m a → (a → m b) → m b
- modifyMVar_ ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m a) → m ()
- swapMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m a
- withMVarMasked ∷ MonadMVar m ⇒ StrictMVar m a → (a → m b) → m b
- modifyMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m (a, b)) → m b
- modifyMVarMasked_ ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m a) → m ()
- modifyMVarMasked ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m (a, b)) → m b
- checkInvariant ∷ HasCallStack ⇒ Maybe String → a → a
- castStrictMVar ∷ ∀ (m ∷ Type → Type) (n ∷ Type → Type) a. LazyMVar m ~ LazyMVar n ⇒ StrictMVar m a → StrictMVar n a
- toLazyMVar ∷ ∀ (m ∷ Type → Type) a. StrictMVar m a → LazyMVar m a
- fromLazyMVar ∷ ∀ (m ∷ Type → Type) a. LazyMVar m a → StrictMVar m a
- unsafeToUncheckedStrictMVar ∷ ∀ (m ∷ Type → Type) a. StrictMVar m a → StrictMVar m a
StrictMVar
newEmptyMVar ∷ (MonadMVar m, NoThunks a) ⇒ m (StrictMVar m a) Source #
Create an empty StrictMVar with a NoThunks invariant.
newEmptyMVarWithInvariant ∷ (MonadMVar m, NoThunks a) ⇒ (a → Maybe String) → m (StrictMVar m a) Source #
Create an empty StrictMVar with a custom invariant and a NoThunks
invariant.
When both the custom and NoThunks invariants are broken, only the error
related to the custom invariant is reported.
newMVar ∷ (HasCallStack, MonadMVar m, NoThunks a) ⇒ a → m (StrictMVar m a) Source #
Create a StrictMVar with a NoThunks invariant.
newMVarWithInvariant ∷ (HasCallStack, MonadMVar m, NoThunks a) ⇒ (a → Maybe String) → a → m (StrictMVar m a) Source #
Create a StrictMVar with a custom invariant and a NoThunks invariant.
When both the custom and NoThunks invariants are broken, only the error
related to the custom invariant is reported.
Invariant
Unchecked
uncheckedNewEmptyMVar ∷ MonadMVar m ⇒ m (StrictMVar m a) Source #
Like newEmptyMVar, but without a NoThunks invariant.
uncheckedNewMVar ∷ MonadMVar m ⇒ a → m (StrictMVar m a) Source #
Re-exports
class Monad m ⇒ MonadMVar (m ∷ Type → Type) Source #
Minimal complete definition
newEmptyMVar, takeMVar, tryTakeMVar, putMVar, tryPutMVar, readMVar, tryReadMVar, isEmptyMVar
Instances
data StrictMVar (m ∷ Type → Type) a Source #
A strict MVar with invariant checking.
There is a weaker invariant for a StrictMVar than for a StrictTVar:
although all functions that modify the StrictMVar check the invariant, we
do not guarantee that the value inside the StrictMVar always satisfies
the invariant. Instead, we do guarantee that if the StrictMVar is updated
with a value that does not satisfy the invariant, an exception is thrown. The
reason for this weaker guarantee is that leaving an MVar empty can lead to
very hard to debug "blocked indefinitely" problems.
takeMVar ∷ MonadMVar m ⇒ StrictMVar m a → m a Source #
readMVar ∷ MonadMVar m ⇒ StrictMVar m a → m a Source #
putMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m () Source #
tryTakeMVar ∷ MonadMVar m ⇒ StrictMVar m a → m (Maybe a) Source #
tryPutMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m Bool Source #
tryReadMVar ∷ MonadMVar m ⇒ StrictMVar m a → m (Maybe a) Source #
isEmptyMVar ∷ MonadMVar m ⇒ StrictMVar m a → m Bool Source #
withMVar ∷ MonadMVar m ⇒ StrictMVar m a → (a → m b) → m b Source #
modifyMVar_ ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m a) → m () Source #
modifyMVar_ is defined in terms of modifyMVar.
swapMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → a → m a Source #
withMVarMasked ∷ MonadMVar m ⇒ StrictMVar m a → (a → m b) → m b Source #
modifyMVar ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m (a, b)) → m b Source #
modifyMVarMasked_ ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m a) → m () Source #
modifyMVarMasked_ is defined in terms of modifyMVarMasked.
modifyMVarMasked ∷ (HasCallStack, MonadMVar m) ⇒ StrictMVar m a → (a → m (a, b)) → m b Source #
checkInvariant ∷ HasCallStack ⇒ Maybe String → a → a Source #
Check invariant (if enabled) before continuing
checkInvariant mErr x is equal to x if mErr == Nothing, and throws
an error err if mErr == Just err.
This is exported so that other code that wants to conditionally check invariants can reuse the same logic, rather than having to introduce new per-package flags.
castStrictMVar ∷ ∀ (m ∷ Type → Type) (n ∷ Type → Type) a. LazyMVar m ~ LazyMVar n ⇒ StrictMVar m a → StrictMVar n a Source #
toLazyMVar ∷ ∀ (m ∷ Type → Type) a. StrictMVar m a → LazyMVar m a Source #
Get the underlying MVar
Since we obviously can not guarantee that updates to this LazyMVar will be
strict, this should be used with caution.
Similarly, we can not guarantee that updates to this LazyMVar do not break
the original invariant that the StrictMVar held.
fromLazyMVar ∷ ∀ (m ∷ Type → Type) a. LazyMVar m a → StrictMVar m a Source #
Create a StrictMVar from a LazyMVar
It is not guaranteed that the LazyMVar contains a value that is in WHNF, so
there is no guarantee that the resulting StrictMVar contains a value that
is in WHNF. This should be used with caution.
The resulting StrictMVar has a trivial invariant.
unsafeToUncheckedStrictMVar ∷ ∀ (m ∷ Type → Type) a. StrictMVar m a → StrictMVar m a Source #
Create an unchecked reference to the given checked StrictMVar.
Note that the invariant is only guaranteed when modifying the checked MVar. Any modification to the unchecked reference might break the invariants.