Struct ExclusiveId 

#[repr(transparent)]
pub struct ExclusiveId {
    pub id: Id,
    /* private fields */
}

Represents an ID that can only be used by a single writer at a time.

ExclusiveIds are associated with one owning context (typically a thread) at a time. Because they are Send and !Sync, they can be passed between contexts, but not used concurrently. This makes use of Rust’s borrow checker to enforce a weaker form of software transactional memory (STM) without rollbacks - as these are not an issue with the heavy use of copy-on-write data structures.

They are automatically associated with the thread they are dropped from, which can be used in queries via the local_ids constraint. You can also make use of explicit IdOwner containers to store them when not actively used in a transaction.

Most methods defined on ExclusiveId are low-level primitives meant to be used for the implementation of new ownership management strategies, such as a transactional database that tracks checked out IDs for ownership, or distributed ledgers like blockchains.

Fields

id: Id

The underlying identifier.

Implementations

impl ExclusiveId

pub fn force(id: Id) -> Self

Forces a regular (read-only) Id to become a writable ExclusiveId.

This is a low-level primitive that is meant to be used for the implementation of new ownership management strategies, such as a transactional database that tracks checked out IDs for ownership, or distributed ledgers like blockchains.

This should be done with care, as it allows scenarios where multiple writers can create conflicting information for the same ID. Similar caution should be applied when using the force_ref and forget methods.

Arguments

• id - The Id to be forced into an ExclusiveId.

pub fn force_ref(id: &Id) -> &Self

Safely transmutes a reference to an Id into a reference to an ExclusiveId.

Similar caution should be applied when using the force method.

Arguments

• id - A reference to the Id to be transmuted.

pub fn release(self) -> Id

Releases the ExclusiveId, returning the underlying Id.

Returns

The underlying Id.

pub fn forget(self) -> Id

Forgets the ExclusiveId, leaking ownership of the underlying Id, while returning it.

This is not as potentially problematic as force, because it prevents further writes with the ExclusiveId, thus avoiding potential conflicts.

Returns

The underlying Id.

Methods from Deref<Target = Id>

pub fn aquire(&self) -> Option<ExclusiveId>

Takes ownership of this Id from the current write context (i.e. thread). Returns None if this Id was not found, because it is not associated with this write context, or because it is currently aquired.

Trait Implementations

impl AsRef<[u8]> for ExclusiveId

fn as_ref(&self) -> &[u8]

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<[u8; 16]> for ExclusiveId

fn as_ref(&self) -> &RawId

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<ExclusiveId> for ExclusiveId

fn as_ref(&self) -> &ExclusiveId

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<ExclusiveId> for OwnedId<'_>

fn as_ref(&self) -> &ExclusiveId

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Id> for ExclusiveId

fn as_ref(&self) -> &Id

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<[u8; 16]> for ExclusiveId

fn borrow(&self) -> &RawId

Immutably borrows from an owned value.

impl Borrow<ExclusiveId> for OwnedId<'_>

fn borrow(&self) -> &ExclusiveId

Immutably borrows from an owned value.

impl Borrow<Id> for ExclusiveId

fn borrow(&self) -> &Id

Immutably borrows from an owned value.

impl Debug for ExclusiveId

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

Formats the value using the given formatter.

impl Deref for ExclusiveId

type Target = Id

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Display for ExclusiveId

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

Formats the value using the given formatter.

impl Drop for ExclusiveId

fn drop(&mut self)

Executes the destructor for this type.

impl Ord for ExclusiveId

fn cmp(&self, other: &ExclusiveId) -> 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,

Restrict a value to a certain interval.

impl PartialEq for ExclusiveId

fn eq(&self, other: &ExclusiveId) -> 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 ExclusiveId

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

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

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 ToValue<GenId> for &ExclusiveId

fn to_value(self) -> Value<GenId>

Convert the Rust type to a Value with a specific schema type. This might cause a panic if the conversion is not possible.

impl ToValue<GenId> for ExclusiveId

fn to_value(self) -> Value<GenId>

Convert the Rust type to a Value with a specific schema type. This might cause a panic if the conversion is not possible.

impl<'a> TryFromValue<'a, GenId> for ExclusiveId

type Error = ExclusiveIdError

The error type returned when the conversion fails.

fn try_from_value(value: &'a Value<GenId>) -> Result<Self, Self::Error>

Convert the Value with a specific schema type to the Rust type.

impl Eq for ExclusiveId

impl Send for ExclusiveId

impl StructuralPartialEq for ExclusiveId