destroyFFIContext stopped and joined the worker threads on every release,
and createFFIContext rebuilt them on the next acquire. Each cycle therefore
allocated a fresh worker — 4 ThreadSignalPtr socketpairs + the ffi/watchdog
thread chronos dispatcher kqueues — and never reclaimed the old ones (the
pool deliberately skips closing them, relying on slot reuse that never
actually reused the resources). A consumer that creates and destroys
contexts repeatedly (e.g. nim-sds ReliabilityManager) leaked ~10 fds per
cycle, unbounded.
Make the pool genuinely reuse a slot's worker:
- Track per-slot `initialized`; createFFIContext builds the worker once and
reuses it on every later acquisition of the same slot.
- Add releaseFFIContext: parks a context (returns its slot) WITHOUT stopping
the threads, so the next acquire reuses the same fds. It also drops the
stale C event callback so a watchdog tick on a parked slot cannot invoke a
callback whose user-data the consumer may already have freed. The caller is
responsible for quiescing its library object (on the FFI thread) first.
- destroyFFIContext keeps full-teardown semantics for error/non-pooling
paths and now marks the slot uninitialised so a later acquire rebuilds it.
Tests: add a park & reuse suite (same-slot live-worker reuse, callback/lib
pointer dropped on park, and fd usage bounded across 20 park/reuse cycles).
The fd test fails by ~10 fds/cycle against the pre-fix behaviour. Green
under both --mm:refc and --mm:orc.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* protect against mem leak in case of failures sending requests to ffi thread
* better cleanup if failures in createFFIContext
* avoid dangling cstring in handleRes under ARC/ORC
* better resource cleanup in destroyFFIContext
* invoke onNotResponding if failure in destroyFFIContext
* correct seq copy in alloc
* make sure the lock is init before cleanUpResources
* better possible exception handling in processReq
* guard allocSharedSeq if given seq is empty
* enhance error handling in ffi_context
* add new tests and some corrections
