nim-ffi/CHANGELOG.md

Changelog

All notable changes to this project are documented in this file.

[Unreleased]

Changed

• User event callbacks now run on a dedicated event thread fed by a bounded SPSC queue (default capacity 1024), so a slow listener can no longer block the FFI thread or concurrent add_event_listener / remove_event_listener calls (#6).
• Replaced the dedicated watchdog thread with a heartbeat check that runs on the event thread. The FFI thread advances an atomic heartbeat each loop iteration; if it stalls for more than 1s past the start-up grace window, the event thread emits the not_responding event.
• declareLibrary no longer emits the shared-library soname / install_name linker flags when building as an executable (--app:lib guard), so FFI code can be unit-tested as a plain binary — fatal on macOS, where -install_name requires -dynamiclib.

Added

• Per-interaction ABI-format annotations: declareLibrary now takes an optional defaultABIFormat ("cbor" default, or "c") that every {.ffi.} / {.ffiCtor.} / {.ffiDtor.} / {.ffiRaw.} / {.ffiEvent.} inherits, and each annotation can override it with an "abi = c" / "abi = cbor" spec (e.g. {.ffi: "abi = cbor".}). declareLibrary is now required before any FFI annotation (#78).
• c (flat C-struct) ABI codec: every {.ffi: "abi = c".} type gets a <T>_CWire companion plus cwirePack / cwireUnpack / cwireFree. This first slice covers the flat path — POD scalars and string (as cstring); composite fields follow. The c proc-dispatch path and the foreign (C++ / Rust) generators are still pending, so c remains rejected on proc/ctor/dtor/event annotations for now.
• tests/bench/bench_codec.nim (+ nimble bench_codec): a single-process microbenchmark comparing the cbor and c codecs across payload shapes, isolating codec cost from the (identical) thread/callback round-trip.
• Queue-overflow handling: when the bounded event queue is full, the library sets a sticky "stuck" flag, logs an error, fires not_responding from the event thread, and rejects subsequent sendRequestToFFIThread calls with event queue stuck - library cannot accept new requests.

[0.2.0] - 2026-06-04

Major release introducing the CBOR-based wire format, CBOR-backed FFI events with a multi-listener registry, multi-language binding generation (C++, Rust, CDDL), CI hardening with sanitizers, and several robustness fixes around context lifetime and memory safety.

Added

• CBOR serialization as the FFI wire format, replacing the previous JSON/string-based serial.nim (#23).
• CBOR-backed FFI events: event payloads are now serialized with CBOR (#39).
• Multi-listener event registry (FFIEventRegistry) and its wiring into FFIContext (#45, #49).
• Event-listener ABI with per-event typed listeners (#50).
• C++ typed per-event listeners in the generated bindings (#51).
• Rust per-event typed listeners (add_on_<x>_listener + wildcard add_event_listener) (#52) and Rust event example bindings/clients (#53).
• C++ binding generator with end-to-end tests driven by CMake/CTest (#27), later expanded with multi-context, cross-library, pipeline, and stress tests (#42).
• CDDL schema generator for the FFI types (#24).
• CI pipeline: parallel test execution (#26), AddressSanitizer / UndefinedBehaviorSanitizer / ThreadSanitizer jobs (#34), and a cross-platform OS matrix for the C++ e2e suite (#38).
• CBOR type-coverage tests (#41).

Changed

• Removed the redundant ffiType macro; the ffi macro is now the single authoring entry point (#22).
• Generated C++ avoids move constructors and assignment operators (#36) and no longer throws exceptions across the binding boundary (#46).
• Removed the wildcard event listener; event dispatch is now strictly per-event (#70).

Fixed

• Use-after-free in the event/context lifetime path (#47).

[0.1.4] - 2026-05-13

Full changelog

Added

• Simplified FFI authoring with auto-generated C++ and Rust language bindings, including new ffi/codegen/cpp.nim, ffi/codegen/rust.nim and shared ffi/codegen/meta.nim helpers (#15).
• Rust example bindings and clients under examples/nim_timer/ (rust_bindings and rust_client, the latter with a Tokio async variant) (#15).
• JSON/string-based FFI (de)serialization via ffi/serial.nim (ffiSerialize/ffiDeserialize), with tests/test_serial.nim coverage. (CBOR replaced this layer later, in 0.2.0.)
• FFI context pool (ffi/ffi_context_pool.nim) using a fixed array of contexts.
• Test suite expansion: test_alloc.nim, test_ctx_validation.nim, test_ffi_context.nim, test_gc_compat.nim.
• Continuous integration pipeline (#12).

Fixed

• Context buffer overflow (#21).
• Use a fixed array of contexts to avoid consuming all file descriptors (#14).
• Memory leaks (#11).
• Add install_name for macOS shared libraries (#8).

Changed

• Run tests with the refc garbage collector (#20).
• Remove CatchableError usage (#19).
• Update license files to comply with Logos licensing requirements.

[0.1.3] - 2026-01-23

Fixed

• Properly import and re-export chronicles so downstream packages get the logging macros transitively.

[0.1.2] - 2026-01-23

Fixed

• Re-export chronicles and std/tables when the ffi module is imported, so generated code resolves these symbols at the call site.

[0.1.1] - 2026-01-23

Initial tagged release.

Added

• Core ffi macro for declaring procs exposed across the FFI boundary.
• FFIContext with a dedicated worker thread, request dispatch, and a watchdog with configurable timeout (#7).
• License files updated to comply with Logos licensing requirements.