Struct FrameMetaSet 

pub struct FrameMetaSet(/* private fields */);

A list of typed FrameMeta attached to a frame. Empty (no allocation) on a freshly constructed frame.

Each entry is an Arc so a fan-out (tee) clone shares the metadata by refcount instead of deep-copying it (cheap, and the analytics graph is identical on both branches). A branch that mutates one entry pays a copy-on-write deep copy only then (see get_mut), so the other branch never observes the change.

Implementations

impl FrameMetaSet

pub fn new() -> Self

An empty metadata set with no backing allocation.

pub fn attach<T: FrameMeta + 'static>(&mut self, meta: T)

Attach one piece of metadata, replacing any entry of the same type (in place, so the order of the other entries is unchanged).

A set holds at most one meta per type: get / get_mut key by type, so a second entry of a type would be unreachable, and an empty one already on the frame would hide what an element attaches later.

pub fn get<T: FrameMeta + 'static>(&self) -> Option<&T>

The attached meta of type T, if any. At most one is ever attached (see attach).

pub fn get_mut<T: FrameMeta + 'static>(&mut self) -> Option<&mut T>

Mutable access to the attached meta of type T, if any (at most one is ever attached, see attach).

Copy-on-write: if the entry is shared with another frame (a tee branch holds the same Arc), it is first deep-copied via FrameMeta::clone_box so this mutation stays private to this frame. When the entry is uniquely owned no copy is made.

pub fn iter(&self) -> impl Iterator<Item = &dyn FrameMeta>

Iterate every attached meta as a trait object.

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn propagate(&mut self, transform: Transform)

Apply a Transform: retain only metas whose propagate returns Propagation::Keep. An element that resamples / re-encodes calls this so stale meta never rides a frame it no longer describes.

Trait Implementations

impl Clone for FrameMetaSet

fn clone(&self) -> FrameMetaSet

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FrameMetaSet

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

Formats the value using the given formatter.

impl Default for FrameMetaSet

fn default() -> FrameMetaSet

Returns the “default value” for a type.