Struct Id

pub struct Id<T> { /* private fields */ }

A struct representing IDs usable for various purposes.

Except for Debug and Display which are implemented unconditionally, the type will only implement Clone, Copy, Eq, Ord, PartialEq, PartialOrd, and Hash if the provided T implements them.

Examples

A commonly seen pattern for creating of a type Id that is unique may look as follows:

use uid::Id as IdT;

#[derive(Copy, Clone, Eq, PartialEq)]
struct T(());

type Id = IdT<T>;

let id1 = Id::new();
let id2 = Id::new();

assert_ne!(id1, id2)

In this example the type T is just an arbitrary type, but it allows us to create distinct ID types. For example, when another ID type is required for a different purpose, that can be easily created:

#[derive(Copy, Clone)]
struct U(());

type Key = IdT<U>;

// `Key` and `Id` are fundamentally different types, with no
// allowed interaction between each other. That is, Rust's type
// system will prevent accidental usage of one in place of the
// other. The same can be said about the relationship to built-in
// numeric types such as `usize` or `u64`.

Implementations

impl<T> Id<T>

pub unsafe fn new_unchecked(id: usize) -> Self

Create a new ID using the given value.

Panics

This constructor panics if an overflow of the underlying counter occurred.

Safety

• id must not be zero
• id should be unique with respect to other IDs created for this T to preserve the invariant that IDs are unique

pub fn new() -> Self

Create a new unique ID.

Panics

This constructor panics if an overflow of the underlying counter occurred.

pub fn get(self) -> usize

Retrieve the underlying integer value.

Trait Implementations

impl<T: Clone> Clone for Id<T>

fn clone(&self) -> Id<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Id<T>

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

Formats the value using the given formatter.

impl<T> Default for Id<T>

fn default() -> Self

Create a new unique ID.

impl<T> Display for Id<T>

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

Format the ID with the given formatter.

impl<T: Hash> Hash for Id<T>

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<T: Ord> Ord for Id<T>

fn cmp(&self, other: &Id<T>) -> 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<T: PartialEq> PartialEq for Id<T>

fn eq(&self, other: &Id<T>) -> 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<T: PartialOrd> PartialOrd for Id<T>

fn partial_cmp(&self, other: &Id<T>) -> 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<T: Copy> Copy for Id<T>

impl<T: Eq> Eq for Id<T>

impl<T> StructuralPartialEq for Id<T>