Struct CompactArc 

pub struct CompactArc<T: ?Sized + CompactArcDrop> { /* private fields */ }

A thread-safe reference-counted pointer without weak reference support.

CompactArc<T> provides shared ownership of a value of type T, allocated on the heap. It saves memory compared to std::sync::Arc:

• 8 bytes less per allocation (no weak count)
• Thin pointers for DSTs (8 bytes instead of 16 for str and [T])

Pointer Sizes

Type	Size
CompactArc<i64>	8 bytes
CompactArc<str>	8 bytes (thin!)
CompactArc<[T]>	8 bytes (thin!)

Implementations

impl<T: ?Sized + CompactArcDrop> CompactArc<T>

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

Returns true if the two CompactArcs point to the same allocation.

pub fn strong_count(this: &Self) -> usize

Returns the number of strong references to this allocation.

Note: This uses Relaxed ordering and should only be used for debugging/logging purposes, not for synchronization decisions.

pub fn meta(this: &Self) -> usize

Returns the metadata stored in the header (used for count).

impl<T: CompactArcDrop> CompactArc<T>

pub fn new(data: T) -> Self

Creates a new CompactArc<T> containing the given value.

pub fn new_with_meta(data: T, meta: usize) -> Self

Creates a new CompactArc<T> containing the given value and metadata. The metadata is stored in the header’s len field, which is unused for Sized types.

pub fn try_unwrap(this: Self) -> Result<T, Self>

Attempts to unwrap the CompactArc, returning the inner value if this is the only reference.

pub fn get_mut(this: &mut Self) -> Option<&mut T>

Gets a mutable reference to the inner value, if there are no other references.

Uses Acquire ordering to synchronize with other threads that may have dropped their references, ensuring all their modifications are visible.

pub fn make_mut(this: &mut Self) -> &mut T

where T: Clone,

Makes a mutable reference to the inner value (clone-on-write).

If there are other references, clones the data into a new allocation.

pub fn as_ptr(this: &Self) -> *const T

Returns a raw pointer to the contained data.

pub fn into_raw(this: Self) -> *const T

Converts a CompactArc<T> into a raw pointer.

pub unsafe fn from_raw(ptr: *const T) -> Self

Constructs a CompactArc<T> from a raw pointer.

Safety

The raw pointer must have been previously returned by CompactArc::into_raw.

impl CompactArc<str>

pub fn from_str_slice(s: &str) -> Self

Creates a new CompactArc<str> from a string slice.

The pointer is only 8 bytes (thin), with length stored in heap header.

pub fn len(&self) -> usize

Returns the length of the string in bytes.

pub fn is_empty(&self) -> bool

Returns true if the string is empty.

impl<T> CompactArc<[T]>

pub fn from_vec(vec: Vec<T>) -> Self

Creates a new CompactArc<[T]> by moving elements from a Vec.

This is more efficient than from_slice as it moves elements instead of cloning.

pub fn from_compact_vec(vec: CompactVec<T>) -> Self

Creates a new CompactArc<[T]> by moving elements from a CompactVec.

This is more efficient than from_slice as it moves elements instead of cloning. Avoids the intermediate Vec conversion compared to from_vec.

impl<T: Clone> CompactArc<[T]>

pub fn from_slice(slice: &[T]) -> Self

Creates a new CompactArc<[T]> from a slice by cloning elements.

The pointer is only 8 bytes (thin), with length stored in heap header.

Panic Safety

If T::clone() panics, all successfully cloned elements are dropped and the allocation is freed. No memory is leaked.

impl<T> CompactArc<[T]>

pub fn len(&self) -> usize

Returns the number of elements in the slice.

pub fn is_empty(&self) -> bool

Returns true if the slice is empty.

Trait Implementations

impl<T: CompactArcDrop> AsRef<T> for CompactArc<T>

fn as_ref(&self) -> &T

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

impl<T> AsRef<[T]> for CompactArc<[T]>

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

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

impl AsRef<str> for CompactArc<str>

fn as_ref(&self) -> &str

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

impl<T: CompactArcDrop> Borrow<T> for CompactArc<T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T> Borrow<[T]> for CompactArc<[T]>

fn borrow(&self) -> &[T]

Immutably borrows from an owned value.

impl Borrow<str> for CompactArc<str>

fn borrow(&self) -> &str

Immutably borrows from an owned value.

impl<T: ?Sized + CompactArcDrop> Clone for CompactArc<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: CompactArcDrop + Debug> Debug for CompactArc<T>

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

Formats the value using the given formatter.

impl Debug for CompactArc<str>

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

Formats the value using the given formatter.

impl<T: Debug> Debug for CompactArc<[T]>

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

Formats the value using the given formatter.

impl<T: CompactArcDrop + Default> Default for CompactArc<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: CompactArcDrop> Deref for CompactArc<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl Deref for CompactArc<str>

type Target = str

The resulting type after dereferencing.

fn deref(&self) -> &str

Dereferences the value.

impl<T> Deref for CompactArc<[T]>

type Target = [T]

The resulting type after dereferencing.

fn deref(&self) -> &[T]

Dereferences the value.

impl<T: CompactArcDrop + Display> Display for CompactArc<T>

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

Formats the value using the given formatter.

impl Display for CompactArc<str>

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

Formats the value using the given formatter.

impl<T: ?Sized + CompactArcDrop> Drop for CompactArc<T>

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl<T: CompactArcDrop + Eq> Eq for CompactArc<T>

impl Eq for CompactArc<str>

impl<T: Eq> Eq for CompactArc<[T]>

impl<T: Clone> From<&[T]> for CompactArc<[T]>

fn from(slice: &[T]) -> Self

Converts to this type from the input type.

impl From<&str> for CompactArc<str>

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<CompactArc<[Value]>> for Row

fn from(values: CompactArc<[Value]>) -> Self

Converts to this type from the input type.

impl From<String> for CompactArc<str>

fn from(s: String) -> Self

Converts to this type from the input type.

impl<T: CompactArcDrop> From<T> for CompactArc<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T> From<Vec<T>> for CompactArc<[T]>

fn from(vec: Vec<T>) -> Self

Converts to this type from the input type.

impl<T: CompactArcDrop + Hash> Hash for CompactArc<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 Hash for CompactArc<str>

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: Hash> Hash for CompactArc<[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: CompactArcDrop + Ord> Ord for CompactArc<T>

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,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl Ord for CompactArc<str>

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,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl<T: Ord> Ord for CompactArc<[T]>

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,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl<T: CompactArcDrop + PartialEq> PartialEq for CompactArc<T>

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

Equality operator ==.

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

Inequality operator !=.

impl PartialEq for CompactArc<str>

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

Equality operator ==.

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

Inequality operator !=.

impl<T: PartialEq> PartialEq for CompactArc<[T]>

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

Equality operator ==.

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

Inequality operator !=.

impl<T: CompactArcDrop + PartialOrd> PartialOrd for CompactArc<T>

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

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 PartialOrd for CompactArc<str>

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

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: PartialOrd> PartialOrd for CompactArc<[T]>

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

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: ?Sized + CompactArcDrop + Send + Sync> Send for CompactArc<T>

impl<T: ?Sized + CompactArcDrop + Send + Sync> Sync for CompactArc<T>