Struct calloop::generic::NoIoDrop

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pub struct NoIoDrop<T>(/* private fields */);
Expand description

A wrapper around a type that doesn’t expose it mutably safely.

The EventSource trait’s Metadata type demands mutable access to the inner I/O source. However, the inner polling source used by calloop keeps the handle-based equivalent of an immutable pointer to the underlying object’s I/O handle. Therefore, if the inner source is dropped, this leaves behind a dangling pointer which immediately invokes undefined behavior on the next poll of the event loop.

In order to prevent this from happening, the Generic I/O source must not directly expose a mutable reference to the underlying handle. This type wraps around the underlying handle and easily allows users to take immutable (&) references to the type, but makes mutable (&mut) references unsafe to get. Therefore, it prevents the source from being moved out and dropped while it is still registered in the event loop.

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impl<T> NoIoDrop<T>

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pub unsafe fn get_mut(&mut self) -> &mut T

Get a mutable reference.

§Safety

The inner type’s I/O source must not be dropped.

Trait Implementations§

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impl<T: AsFd> AsFd for NoIoDrop<T>

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fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor. Read more
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impl<T> AsRef<T> for NoIoDrop<T>

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fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.
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impl<T> Borrow<T> for NoIoDrop<T>

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T: Debug> Debug for NoIoDrop<T>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<T> Deref for NoIoDrop<T>

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type Target = T

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.

Auto Trait Implementations§

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impl<T> Freeze for NoIoDrop<T>
where T: Freeze,

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impl<T> RefUnwindSafe for NoIoDrop<T>
where T: RefUnwindSafe,

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impl<T> Send for NoIoDrop<T>
where T: Send,

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impl<T> Sync for NoIoDrop<T>
where T: Sync,

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impl<T> Unpin for NoIoDrop<T>
where T: Unpin,

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impl<T> UnwindSafe for NoIoDrop<T>
where T: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> AsSource for T
where T: AsFd,

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fn source(&self) -> BorrowedFd<'_>

Returns the borrowed file descriptor.
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more