Enum memfile::Seal

#[repr(u32)]
#[non_exhaustive]
pub enum Seal {
    Seal,
    Shrink,
    Grow,
    Write,
    FutureWrite,
}

A seal that prevents certain actions from being performed on a file.

Note that seals apply to a file, not a file descriptor. If two file descriptors refer to the same file, they share the same set of seals.

Seals can not be removed from a file once applied.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Seal

Prevent adding more seals to the file.

Shrink

Prevent the file from being shrunk with truncate or similar.

Combine with Seal::Grow to prevent the file from being resized in any way.

Grow

Prevent the file from being extended with truncate, fallocate or simillar.

Combine with Seal::Shrink to prevent the file from being resized in any way.

Write

Prevent write to the file.

This will block all writes to the file and prevents any shared, writable memory mappings from being created.

If a shared, writable memory mapping already exists, adding this seal will fail.

FutureWrite

Similar to Seal::Write, but allows existing shared, writable memory mappings to modify the file contents.

This can be used to share a read-only view of the file with other processes, while still being able to modify the contents through an existing mapping.

Trait Implementations

impl BitAnd<Seal> for Seal

type Output = Seals

The resulting type after applying the & operator.

fn bitand(self, right: Seal) -> Seals

Performs the & operation.

impl BitAnd<Seals> for Seal

type Output = Seals

The resulting type after applying the & operator.

fn bitand(self, right: Seals) -> Seals

Performs the & operation.

impl BitOr<Seal> for Seal

type Output = Seals

The resulting type after applying the | operator.

fn bitor(self, right: Seal) -> Seals

Performs the | operation.

impl BitOr<Seals> for Seal

type Output = Seals

The resulting type after applying the | operator.

fn bitor(self, right: Seals) -> Seals

Performs the | operation.

impl BitXor<Seal> for Seal

type Output = Seals

The resulting type after applying the ^ operator.

fn bitxor(self, right: Seal) -> Seals

Performs the ^ operation.

impl BitXor<Seals> for Seal

type Output = Seals

The resulting type after applying the ^ operator.

fn bitxor(self, right: Seals) -> Seals

Performs the ^ operation.

impl Clone for Seal

fn clone(&self) -> Seal

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Seal

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

Formats the value using the given formatter.

impl From<Seal> for Seals

fn from(other: Seal) -> Self

Performs the conversion.

impl Hash for Seal

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, 

Feeds a slice of this type into the given Hasher.

impl Ord for Seal

fn cmp(&self, other: &Seal) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<Seal> for Seal

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialOrd<Seal> for Seal

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

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl Sub<Seal> for Seal

type Output = Seals

The resulting type after applying the - operator.

fn sub(self, right: Seal) -> Seals

Performs the - operation.

impl Sub<Seals> for Seal

type Output = Seals

The resulting type after applying the - operator.

fn sub(self, right: Seals) -> Seals

Performs the - operation.

impl Copy for Seal

impl Eq for Seal

impl StructuralEq for Seal

impl StructuralPartialEq for Seal