Enum memfile::Seal

#[non_exhaustive]
#[repr(u32)]
pub enum Seal {
    Seal = 1,
    Shrink = 2,
    Grow = 4,
    Write = 8,
    FutureWrite = 16,
}

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 = 1

Prevent adding more seals to the file.

Shrink = 2

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 = 4

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 = 8

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 = 16

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<Seals> for Seal

type Output = Seals

The resulting type after applying the & operator.

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

Performs the & operation.

impl BitAnd for Seal

type Output = Seals

The resulting type after applying the & operator.

fn bitand(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 BitOr for Seal

type Output = Seals

The resulting type after applying the | operator.

fn bitor(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 BitXor for Seal

type Output = Seals

The resulting type after applying the ^ operator.

fn bitxor(self, right: Seal) -> 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

Converts to this type from the input type.

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, Self: Sized,

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

where Self: Sized,

Compares and returns the maximum of two values.

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

where Self: Sized,

Compares and returns the minimum of two values.

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

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

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

impl PartialOrd 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<Seals> for Seal

type Output = Seals

The resulting type after applying the - operator.

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

Performs the - operation.

impl Sub for Seal

type Output = Seals

The resulting type after applying the - operator.

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

Performs the - operation.

impl Copy for Seal

impl Eq for Seal

impl StructuralEq for Seal

impl StructuralPartialEq for Seal