## CacheLockMode

# Enum CacheLockMode

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    pub enum CacheLockMode {
        DownloadExclusive,
        Shared,
        MutateExclusive,
    }

Expand description

The style of lock to acquire.

## Variants§

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### DownloadExclusive

A `DownloadExclusive` lock ensures that only one cargo is doing resolution and downloading new packages.

You should use this when downloading new packages or doing resolution.

If another cargo has a `MutateExclusive` lock, then an attempt to get a `DownloadExclusive` lock will block.

If another cargo has a `Shared` lock, then both can operate concurrently.

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### Shared

A `Shared` lock allows multiple cargos to read from the source files.

You should use this when cargo is reading source files from the package cache. This is typically done during the build phase, since cargo only needs to read files during that time. This allows multiple cargo processes to build concurrently without interfering with one another, while guarding against other cargos using `MutateExclusive`.

If another cargo has a `MutateExclusive` lock, then an attempt to get a `Shared` will block.

If another cargo has a `DownloadExclusive` lock, then they both can operate concurrently under the assumption that downloading does not modify existing source files.

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### MutateExclusive

A `MutateExclusive` lock ensures no other cargo is reading or writing from the package caches.

You should use this when modifying existing files in the package cache. For example, things like garbage collection want to avoid deleting files while other cargos are trying to read (`Shared`) or resolve or download (`DownloadExclusive`).

If another cargo has a `DownloadExclusive` or `Shared` lock, then this will block until they all release their locks.

## Trait Implementations§

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### impl Clone for CacheLockMode

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#### fn clone(&self) -> CacheLockMode

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for CacheLockMode

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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 PartialEq for CacheLockMode

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#### fn eq(&self, other: &CacheLockMode) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl Copy for CacheLockMode

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### impl StructuralPartialEq for CacheLockMode

## Auto Trait Implementations§

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### impl Freeze for CacheLockMode

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### impl RefUnwindSafe for CacheLockMode

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### impl Send for CacheLockMode

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### impl Sync for CacheLockMode

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### impl Unpin for CacheLockMode

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### impl UnwindSafe for CacheLockMode

## 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> 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> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. 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> IntoEither for T

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#### fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left` is `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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#### fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts `self` into a `Left` variant of `Either<Self, Self>` if `into_left(&self)` returns `true`. Converts `self` into a `Right` variant of `Either<Self, Self>` otherwise. Read more
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### impl<T> Pointable for T

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#### const ALIGN: usize

The alignment of pointer.
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#### type Init = T

The type for initializers.
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#### unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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#### unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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#### unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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#### unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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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<V, T> VZip<V> for T
where V: MultiLane<T>,

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#### fn vzip(self) -> V

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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

## Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain `repr(...)` attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 1 byte

Size for each variant:

- `DownloadExclusive`: 0 bytes
- `Shared`: 0 bytes
- `MutateExclusive`: 0 bytes