Struct miri::borrow_tracker::tree_borrows::perms::Permission

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pub struct Permission {
    inner: PermissionPriv,
}
Expand description

Public interface to the state machine that controls read-write permissions. This is the “private enum” pattern.

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§inner: PermissionPriv

Implementations§

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impl Permission

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pub fn short_name(self) -> &'static str

Abbreviated name of the permission (uniformly 3 letters for nice alignment).

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impl Permission

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pub fn is_initial(&self) -> bool

Check if self can be the initial state of a pointer.

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pub fn is_disabled(&self) -> bool

Check if self is the terminal state of a pointer (is Disabled).

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pub fn is_active(&self) -> bool

Check if self is the post-child-write state of a pointer (is Active).

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pub fn new_active() -> Self

Default initial permission of the root of a new tree at inbounds positions. Must only be used for the root, this is not in general an “initial” permission!

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fn new_reserved_frz() -> Self

Default initial permission of a reborrowed mutable reference that is either protected or not interior mutable.

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fn new_reserved_im() -> Self

Default initial permission of an unprotected interior mutable reference.

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pub fn new_reserved(ty_is_freeze: bool, protected: bool) -> Self

Wrapper around new_reserved_frz and new_reserved_im that decides which to call based on the interior mutability and the retag kind (whether there is a protector is relevant because being protected takes priority over being interior mutable)

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pub fn new_frozen() -> Self

Default initial permission of a reborrowed shared reference.

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pub fn new_disabled() -> Self

Default initial permission of the root of a new tree at out-of-bounds positions. Must only be used for the root, this is not in general an “initial” permission!

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pub fn compatible_with_protector(&self) -> bool

Reject ReservedIM that cannot exist in the presence of a protector.

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pub fn perform_access( kind: AccessKind, rel_pos: AccessRelatedness, old_perm: Self, protected: bool, ) -> Option<PermTransition>

Apply the transition to the inner PermissionPriv.

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pub fn can_be_replaced_by_child(self, child: Self) -> bool

During a provenance GC, we want to compact the tree. For this, we want to merge nodes upwards if they have a singleton parent. But we need to be careful: If the parent is Frozen, and the child is Reserved, we can not do such a merge. In general, such a merge is possible if the parent allows similar accesses, and in particular if the parent never causes UB on its own. This is enforced by a test, namely tree_compacting_is_sound. See that test for more information. This method is only sound if the parent is not protected. We never attempt to remove protected parents.

Trait Implementations§

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impl Clone for Permission

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fn clone(&self) -> Permission

Returns a copy 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 Permission

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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 Display for Permission

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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 Hash for Permission

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl PartialEq for Permission

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fn eq(&self, other: &Permission) -> 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 PartialOrd for Permission

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fn partial_cmp(&self, other: &Permission) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Copy for Permission

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impl Eq for Permission

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impl StructuralPartialEq for Permission

Auto Trait Implementations§

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, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. 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, 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> 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> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. 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

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