Struct ptr_meta::DynMetadata

#[repr(transparent)]
pub struct DynMetadata<Dyn: ?Sized> { /* private fields */ }

The metadata for a Dyn = dyn SomeTrait trait object type.

It is a pointer to a vtable (virtual call table) that represents all the necessary information to manipulate the concrete type stored inside a trait object. The vtable notably it contains:

• type size
• type alignment
• a pointer to the type’s drop_in_place impl (may be a no-op for plain-old-data)
• pointers to all the methods for the type’s implementation of the trait

Note that the first three are special because they’re necessary to allocate, drop, and deallocate any trait object.

It is possible to name this struct with a type parameter that is not a dyn trait object (for example DynMetadata<u64>) but not to obtain a meaningful value of that struct.

Implementations

impl<Dyn: ?Sized> DynMetadata<Dyn>

pub fn size_of(self) -> usize

Returns the size of the type associated with this vtable.

pub fn align_of(self) -> usize

Returns the alignment of the type associated with this vtable.

pub fn layout(self) -> Layout

Returns the size and alignment together as a Layout.

Trait Implementations

impl<Dyn: ?Sized> Clone for DynMetadata<Dyn>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<Dyn: ?Sized> Debug for DynMetadata<Dyn>

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

Formats the value using the given formatter.

impl<Dyn: ?Sized> Hash for DynMetadata<Dyn>

fn hash<H: Hasher>(&self, hasher: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl<Dyn: ?Sized> Ord for DynMetadata<Dyn>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

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

Compares and returns the maximum of two values.

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

Compares and returns the minimum of two values.

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

Restrict a value to a certain interval.

impl<Dyn: ?Sized> PartialEq<DynMetadata<Dyn>> for DynMetadata<Dyn>

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 !=.

impl<Dyn: ?Sized> PartialOrd<DynMetadata<Dyn>> for DynMetadata<Dyn>

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<Dyn: ?Sized> Copy for DynMetadata<Dyn>

impl<Dyn: ?Sized> Eq for DynMetadata<Dyn>

impl<Dyn: ?Sized> Send for DynMetadata<Dyn>

impl<Dyn: ?Sized> Sync for DynMetadata<Dyn>

impl<Dyn: ?Sized> Unpin for DynMetadata<Dyn>