Struct TagSetMutView 

pub struct TagSetMutView<'a, 'b> { /* private fields */ }

A lazy copy-on-write mutable view over a Context’s tag sets.

Operations on this view (e.g. retain_tags) are recorded but not applied immediately. The actual Arc clone, mutation, and context key recomputation only occur when finish is called, and only if changes were recorded.

Implementations

impl<'a, 'b> TagSetMutView<'a, 'b>

pub fn retain_tags(&mut self, f: impl FnMut(&Tag) -> bool)

Scan instrumented tags with the given predicate.

Tags for which f returns false are flagged for removal. This is a read-only scan; no mutation occurs until finish is called.

pub fn retain_origin_tags(&mut self, f: impl FnMut(&Tag) -> bool)

Scan origin tags with the given predicate.

Tags for which f returns false are flagged for removal. This is a read-only scan; no mutation occurs until finish is called.

pub fn finish(self) -> usize

Apply all recorded changes and return the total number of tags affected.

If no changes were recorded, this is a no-op: no Arc clone, no rehash, returns 0. Otherwise, triggers Arc::make_mut on the context, applies the changes to both tag sets, and recomputes the context key.

Returns the number of tags removed.

Trait Implementations

impl Drop for TagSetMutView<'_, '_>

fn drop(&mut self)

Executes the destructor for this type.