Struct wasmtime_runtime::VMExternRefActivationsTable

#[repr(C)]
pub struct VMExternRefActivationsTable { /* private fields */ }

A table that over-approximizes the set of VMExternRefs that any Wasm activation on this thread is currently using.

Under the covers, this is a simple bump allocator that allows duplicate entries. Deduplication happens at GC time.

Implementations

impl VMExternRefActivationsTable

pub fn new() -> Self

Create a new VMExternRefActivationsTable.

pub fn bump_capacity_remaining(&self) -> usize

Get the available capacity in the bump allocation chunk.

pub fn try_insert(&mut self, externref: VMExternRef) -> Result<(), VMExternRef>

Try and insert a VMExternRef into this table.

This is a fast path that only succeeds when the bump chunk has the capacity for the requested insertion.

If the insertion fails, then the VMExternRef is given back. Callers may attempt a GC to free up space and try again, or may call insert_slow_path to infallibly insert the reference (potentially allocating additional space in the table to hold it).

pub unsafe fn insert_with_gc( &mut self, externref: VMExternRef, module_info_lookup: &dyn ModuleInfoLookup )

Insert a reference into the table, falling back on a GC to clear up space if the table is already full.

Unsafety

The same as gc.

pub fn insert_without_gc(&mut self, externref: VMExternRef)

Insert a reference into the table, without ever performing GC.

pub fn set_gc_okay(&mut self, okay: bool) -> bool

Set whether it is okay to GC or not right now.

This is provided as a helper for enabling various debug-only assertions and checking places where the wasmtime-runtime user expects there not to be any GCs.