Struct ThreadLocalArena 

pub struct ThreadLocalArena;

Thread-local, BTreeMap-backed reference-counted GC protection arena.

This provides the lowest overhead for protection operations by eliminating RefCell borrow checking — each thread gets its own ThreadLocalState (private) accessed through an UnsafeCell.

use miniextendr_api::refcount_protect::ThreadLocalArena;
unsafe { ThreadLocalArena::protect(x) };

Implementations

impl ThreadLocalArena

fn with_state<R, F: FnOnce(&mut ThreadLocalState) -> R>(f: F) -> R

Access the thread-local state.

pub unsafe fn init()

Initialize the arena with default capacity (called automatically on first use).

Safety

Must be called from the R main thread.

pub unsafe fn init_with_capacity(capacity: usize)

Initialize the arena with specific capacity.

Use this when you know the expected number of distinct protected values to avoid backing VECSXP growth and map rehashing during operation.

If already initialized, this is a no-op.

Safety

Must be called from the R main thread.

pub unsafe fn protect(x: SEXP) -> SEXP

Protect a SEXP, incrementing its reference count.

Safety

Must be called from the R main thread.

pub unsafe fn unprotect(x: SEXP)

Unprotect a SEXP.

Safety

Must be called from the R main thread.

pub unsafe fn try_unprotect(x: SEXP) -> bool

Try to unprotect a SEXP.

Safety

Must be called from the R main thread.

pub unsafe fn protect_fast(x: SEXP) -> SEXP

Protect without checking initialization.

For hot loops where init() or init_with_capacity() has already been called.

Safety

• Must be called from the R main thread.
• The arena must have been initialized via init() or init_with_capacity().

pub unsafe fn unprotect_fast(x: SEXP)

Unprotect without checking initialization.

For hot loops where init() or init_with_capacity() has already been called.

Safety

• Must be called from the R main thread.
• The arena must have been initialized via init() or init_with_capacity().

pub unsafe fn try_unprotect_fast(x: SEXP) -> bool

Try to unprotect without checking initialization.

For hot loops where init() or init_with_capacity() has already been called.

Safety

• Must be called from the R main thread.
• The arena must have been initialized via init() or init_with_capacity().

pub fn is_protected(x: SEXP) -> bool

Check if a SEXP is protected.

pub fn ref_count(x: SEXP) -> usize

Get reference count.

pub fn len() -> usize

Number of protected SEXPs.

pub fn is_empty() -> bool

Check if empty.

pub fn capacity() -> usize

Get capacity.

pub unsafe fn clear()

Clear all protections.

Safety

Must be called from the R main thread.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 0 bytes