Enum PermissionPriv

enum PermissionPriv {
    ReservedFrz {
        conflicted: bool,
    },
    ReservedIM,
    Active,
    Frozen,
    Disabled,
}

The activation states of a pointer.

Variants

ReservedFrz

represents: a local mutable reference that has not yet been written to; allows: child reads, foreign reads; affected by: child writes (becomes Active), rejects: foreign writes (Disabled).

ReservedFrz is mostly for types that are Freeze (no interior mutability). If the type has interior mutability, see ReservedIM instead. (Note: since the discovery of tests/fail/tree_borrows/reservedim_spurious_write.rs, we also use ReservedFreeze for mutable references that were retagged with a protector independently of interior mutability)

special case: behaves differently when protected, which is where conflicted is relevant

• conflicted is set on foreign reads,
• conflicted must not be set on child writes (there is UB otherwise).

This is so that the behavior of Reserved adheres to the rules of noalias:

• foreign-read then child-write is UB due to conflicted,
• child-write then foreign-read is UB since child-write will activate and then foreign-read disables a protected Active, which is UB.

Fields

conflicted: bool

ReservedIM

Alternative version of ReservedFrz made for types with interior mutability. allows: child reads, foreign reads, foreign writes (extra); affected by: child writes (becomes Active); rejects: nothing.

Active

represents: a unique pointer; allows: child reads, child writes; rejects: foreign reads (Frozen), foreign writes (Disabled).

Frozen

represents: a shared pointer; allows: all read accesses; rejects child writes (UB), foreign writes (Disabled).

Disabled

represents: a dead pointer; allows: all foreign accesses; rejects: all child accesses (UB).

Implementations

impl PermissionPriv

fn is_initial(&self) -> bool

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

fn compatible_with_protector(&self) -> bool

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

fn strongest_idempotent_foreign_access( &self, prot: bool, ) -> IdempotentForeignAccess

See foreign_access_skipping.rs. Computes the SIFA of a permission.

Trait Implementations

impl Clone for PermissionPriv

fn clone(&self) -> PermissionPriv

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PermissionPriv

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

Formats the value using the given formatter.

impl Display for PermissionPriv

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

Formats the value using the given formatter.

impl Hash for PermissionPriv

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

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for PermissionPriv

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

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

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

impl PartialOrd for PermissionPriv

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

PermissionPriv is ordered by the reflexive transitive closure of Reserved(conflicted=false) < Reserved(conflicted=true) < Active < Frozen < Disabled. Reserved that have incompatible ty_is_freeze are incomparable to each other. This ordering matches the reachability by transitions, as asserted by the exhaustive test permissionpriv_partialord_is_reachability.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

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

impl Copy for PermissionPriv

impl Eq for PermissionPriv

impl StructuralPartialEq for PermissionPriv

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:

• ReservedFrz: 1 byte
• ReservedIM: 0 bytes
• Active: 0 bytes
• Frozen: 0 bytes
• Disabled: 0 bytes