Struct AtomicInvariant

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pub struct AtomicInvariant<T>(/* private fields */);

Implementations§

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impl<T: Protocol> AtomicInvariant<T>

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pub fn new( value: Ghost<T>, public: Snapshot<T::Public>, namespace: Snapshot<Namespace>, ) -> Ghost<Self>

Construct a AtomicInvariant

§Parameters

value: the actual data contained in the invariant. Use Self::open to access it. Also called the ‘private’ part of the invariant.
public: the ‘public’ part of the invariant.
namespace: the namespace of the invariant. This is required to avoid opening the same invariant twice.

requires

value.protocol(*public)

ensures

result.public() == *public

ensures

result.namespace() == *namespace

terminates

ghost

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pub fn namespace(self) -> Namespace

Get the namespace associated with this invariant.

(opaque) ^⚠

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pub fn public(self) -> T::Public

Get the ‘public’ part of this invariant.

(opaque) ^⚠

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pub fn into_inner(self) -> T

Gives the actual invariant held by the AtomicInvariant.

ensures

result.protocol(self.public())

terminates

ghost

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pub fn open<A>( &self, tokens: Tokens<'_>, f: impl FnGhost + for<'a> FnOnce(&'a mut T) -> A, ) -> A

Open the invariant to get the data stored inside.

This will call the closure f with the inner data. You must restore the contained Protocol before returning from the closure.

NOTE: This function can only be called from ghost code, because atomic invariants are always wrapped in Ghost. This guarantees atomicity.

requires

tokens.contains(self.namespace())

requires

forall<t: &mut T> t.protocol(self.public()) && inv(t) ==>
        f.precondition((t,)) &&
        // f must restore the invariant
        (forall<res: A> f.postcondition_once((t,), res) ==> (^t).protocol(self.public()))

ensures

exists<t: &mut T> inv(t) && t.protocol(self.public()) && f.postcondition_once((t,), result)

terminates

ghost

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pub fn open_const<'a>(&'a self, tokens: &'a Tokens<'_>) -> &'a T

Open the invariant to get the data stored inside, immutably.

NOTE: This is the counterpart of NonAtomicInvariant::open_const, but it is not expected to be useful in practice as atomicity prevents re-entrancy anyway.

requires