Struct refuse::Root

pub struct Root<T>
where
    T: Collectable,
{ /* private fields */ }

A root reference to a T that has been allocated in the garbage collector.

This type behaves very similarly to Arc<T>. It implements Deref<Target = T>, and it is also cheap-to-clone, utilizing atomic reference counting to track the number of root references currently exist to the underlying value.

While any root references exist for a given allocation, the garbage collector will not collect the allocation.

Implementations

impl<T> Root<T>

where T: Collectable,

pub fn new<'a>(value: T, guard: impl AsRef<CollectionGuard<'a>>) -> Self

Stores value in the garbage collector, returning a root reference to the data.

Examples found in repository

examples/trace.rs (line 15)

fn main() {
    let mut guard = CollectionGuard::acquire();

    let message = Ref::new(String::from("Hello!"), &guard);
    let error = Root::new(Error { message }, &guard);

    // Because `error` is a Root and refers to the message,
    guard.collect();

    assert_eq!(message.load(&guard).expect("still alive"), "Hello!");

    // After we drop the Root, the message will be able to be collected.
    drop(error);
    guard.collect();
    assert_eq!(message.load(&guard), None);
}

examples/basic.rs (line 8)

fn main() {
    let guard = CollectionGuard::acquire();
    // Allocate a vec![Ref(1), Ref(2), Ref(3)].
    let values: Vec<Ref<u32>> = (1..=3).map(|value| Ref::new(value, &guard)).collect();
    let values = Root::new(values, &guard);
    drop(guard);

    // Manually execute the garbage collector. Our data will not be freed,
    // since `values` is a "root" reference.
    refuse::collect();

    // Root references allow direct access to their data, even when a
    // `CollectionGuard` isn't held.
    let (one, two, three) = (values[0], values[1], values[2]);

    // Accessing the data contained in a `Ref` requires a guard, however.
    let mut guard = CollectionGuard::acquire();
    assert_eq!(one.load(&guard), Some(&1));
    assert_eq!(two.load(&guard), Some(&2));
    assert_eq!(three.load(&guard), Some(&3));

    // Dropping our root will allow the collector to free our `Ref`s.
    drop(values);
    guard.collect();
    assert_eq!(one.load(&guard), None);
}

pub fn try_from_any<'a>( root: AnyRoot, guard: impl AsRef<CollectionGuard<'a>> ) -> Result<Self, AnyRoot>

Try to convert a typeless root reference into a Root<T>.

Errors

Returns Err(root) if root does not contain a T.

pub fn root_count(&self) -> u64

Returns the current number of root references to this value, including self.

pub const fn downgrade(&self) -> Ref<T>

Returns a “weak” reference to this root.

pub const fn downgrade_any(&self) -> AnyRef

Returns an untyped “weak” reference erased to this root.

pub fn to_any_root(&self) -> AnyRoot

Returns an untyped root reference.

pub fn into_any_root(self) -> AnyRoot

Returns this root as an untyped root.

pub fn ptr_eq(this: &Self, other: &Self) -> bool

Returns true if these two references point to the same underlying allocation.

Trait Implementations

impl<T> AsRef<Ref<T>> for Root<T>

where T: Collectable,

fn as_ref(&self) -> &Ref<T>

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

impl<T> Clone for Root<T>

where T: Collectable,

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Root<T>

where T: Collectable + Debug,

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

Formats the value using the given formatter.

impl<T> Deref for Root<T>

where T: Collectable,

type Target = T

The resulting type after dereferencing.

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

Dereferences the value.

impl<T> Drop for Root<T>

where T: Collectable,

fn drop(&mut self)

Executes the destructor for this type.

impl<T> From<&Root<T>> for AnyRef

where T: Collectable,

fn from(value: &Root<T>) -> Self

Converts to this type from the input type.

impl<T> From<Root<T>> for AnyRoot

where T: Collectable,

fn from(value: Root<T>) -> Self

Converts to this type from the input type.

impl<T> Hash for Root<T>

where T: Collectable + Hash,

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 for Root<T>

where T: Collectable + Ord,

fn cmp(&self, other: &Self) -> 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<T> PartialEq<&AnyRef> for Root<T>

where T: Collectable,

fn eq(&self, other: &&AnyRef) -> 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<T> PartialEq<&Ref<T>> for Root<T>

where T: Collectable,

fn eq(&self, other: &&Ref<T>) -> 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<T> PartialEq<&Root<T>> for Ref<T>

where T: Collectable,

fn eq(&self, other: &&Root<T>) -> 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<T> PartialEq<AnyRef> for Root<T>

where T: Collectable,

fn eq(&self, other: &AnyRef) -> 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<T> PartialEq<Ref<T>> for Root<T>

where T: Collectable,

fn eq(&self, other: &Ref<T>) -> 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<T> PartialEq<Root<T>> for Ref<T>

where T: Collectable,

fn eq(&self, other: &Root<T>) -> 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<T> PartialEq for Root<T>

where T: Collectable + PartialEq,

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

where T: Collectable + PartialOrd,

fn partial_cmp(&self, other: &Self) -> 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<T> Trace for Root<T>

where T: Collectable,

const MAY_CONTAIN_REFERENCES: bool = false

If true, this type may contain references and should have its trace() function invoked during the collector’s “mark” phase.

fn trace(&self, _tracer: &mut Tracer<'_>)

Traces all refrences that this value references.

impl<T> Eq for Root<T>

where T: Collectable + Eq,

impl<T> Send for Root<T>

where T: Collectable,

impl<T> Sync for Root<T>

where T: Collectable,