Struct Mutation

pub struct Mutation<'gc> { /* private fields */ }

Handle value given by arena callbacks during construction and mutation. Allows allocating new Gc pointers and internally mutating values held by Gc pointers.

Implementations

impl<'gc> Mutation<'gc>

pub fn metrics(&self) -> &Metrics

pub fn backward_barrier(&self, parent: Gc<'gc, ()>, child: Option<Gc<'gc, ()>>)

IF we are in the marking phase AND the parent pointer is colored black AND the child (if given) is colored white, then change the parent color to gray and enqueue it for tracing.

This operation is known as a “backwards write barrier”. Calling this method is one of the safe ways for the value in the parent pointer to use internal mutability to adopt the child pointer without invalidating the color invariant.

If the child parameter is given, then calling this method ensures that the parent pointer may safely adopt the child pointer. If no child is given, then calling this method is more general, and it ensures that the parent pointer may adopt any child pointer(s) before collection is next triggered.

pub fn forward_barrier(&self, parent: Option<Gc<'gc, ()>>, child: Gc<'gc, ()>)

IF we are in the marking phase AND the parent pointer (if given) is colored black, AND the child is colored white, then immediately change the child to gray and enqueue it for tracing.

This operation is known as a “forwards write barrier”. Calling this method is one of the safe ways for the value in the parent pointer to use internal mutability to adopt the child pointer without invalidating the color invariant.

If the parent parameter is given, then calling this method ensures that the parent pointer may safely adopt the child pointer. If no parent is given, then calling this method is more general, and it ensures that the child pointer may be adopted by any parent pointer(s) before collection is next triggered.