Changelog

All notable changes to xtils are documented here (reverse chronological order).

Format: type(scope): description — types: feat, fix, refactor, chore, tidy.

---

v2.0.0 2026-06

Major release. Tagged after the v1.x deprecation grace period; all snake_case wrappers and compat shims are gone.

💥 BREAKING CHANGES — deprecated APIs removed

Header	Removed	Replacement
xtils/app/app.h	App::registor/ins/run/run_daemon/init/is_running/spawn/spawn_async/every/delay/emit/connect/conf	App::Register/Ins/Run/RunDaemon/Init/IsRunning/Spawn/SpawnAsync/Every/Delay/Emit/Connect/Conf
xtils/app/service.h	Service::emit, xtils::isOk/init/shutdown/run_forever/run_daemon	Service::Emit, xtils::IsOk/Init/Shutdown/RunForever/RunDaemon
xtils/tasks/task_group.h	is_busy/size/stop/stop_wait_all/main_runner	IsBusy/Size/Stop/StopWaitAll/MainRunner
xtils/utils/thread_safe.h	pop_wait/try_pop/push/clear/size/quit	PopWait/TryPop/Push/Clear/Size/Quit
xtils/config/config_compat.h	entire file deleted	Use PascalCase API (Define/ParseArgs/LoadFile/ParseJson/Get/GetOr, ...)
xtils/fsm/fsm_compat.h	entire file deleted	Use PascalCase API
XTILS_ENABLE_DEPRECATED macro	no longer recognised	Remove from your build system

🌟 v2.0 highlights (cumulative since v1.2.1)

New modules

• xtils/metrics/ — lightweight metrics primitives: Counter/Gauge/Histogram with labelled families and PrometheusExporter text rendering
• xtils/scripting/ — embedded QuickJS-NG JavaScript engine, ScriptEngine/ScriptContext/ScriptValue, bidirectional Json ↔ ScriptValue conversion. Opt-in via SCRIPTING_ENABLE=ON
• xtils/net/ipc_channel.h — JSON-RPC 2.0 over filesystem Unix / abstract Unix / TCP sockets. IpcServer / IpcClient with sync call, async call, notifications and subscriptions
• xtils/net/http_client_pool.h — fixed-size HTTP client pool with RAII borrow handle and acquire timeout

Logging — structured logs

• xtils/logging/mdc.h — Mapped Diagnostic Context, thread-local key/value context auto-appended to structured output
• xtils/logging/log_builder.h — chained-field API: LOGI().Field("req_id", id).Field("status", code).Msg("done");
• Logging rewrite: atomic level checks (no mutex on hot path), LogEntry stores const char* literals (zero copy), raw timespec formatted lazily, new Formatter interface (PlainFormatter/ColorFormatter) per sink
• Assertion macros renamed to XTILS_CHECK/XTILS_DCHECK/XTILS_FATAL (opt-in short names via XTILS_LOG_SHORT_MACROS)

Net

• HTTP type cleanup: HttpClient::Request/Response/Listener/MultipartField/MultipartFile are now nested types; the synchronous entry point unifies into HttpClient::Send(). Server/router scoped names exposed as HttpServer::Request/Connection, HttpRouter::Context/Response. Old HttpRequest/HttpResponse public-header collisions removed
• Router: path parameters now support both Express-style :param and the existing {param} syntax
• HttpServer: new HttpServerConfig with configurable max_payload_size (default 4 MB) for memory-constrained devices
• Multipart parsing: MultipartParser plus lazy GetMultipartFields() / GetMultipartFiles() on the request context
• File streaming: HttpServerConnection::SendFileStreaming() chunked delivery (64 KB chunks)
• WebSocket: client owns its HTTP upgrade handshake directly — no more dependency on HttpClient / HttpClientEventListener. WSS supported
• TLS backends: TLS_BACKEND=openssl|mbedtls CMake option; backend-agnostic tls_factory.h
• HttpClient: single-flight start/cancel made explicit and atomic; timeout callbacks no longer touch destroyed clients

Tasks

• TaskRunner extensions: PostDelayedTaskWithHandle / CancelDelayedTask, PostTaskAt(time_point), virtual Now() for fake-clock tests
• CronScheduler::TaskInfo gains nextRun; triggerCheck() locks the task map
• TaskGroup PascalCased; perf: tasks moved into / out of queues to avoid extra std::function copies

Config

• Config::LoadEnv(prefix) — import <PREFIX>_<KEY> env vars into dot-notation paths
• Config::Short(name, alias) — single-character short flag (e.g. -p for --port)
• ConfigWatcher (xtils/config/config_watcher.h) — inotify-based hot reload
• GetOr<T> two overloads: explicit fallback / Defined default

App / Service

• IService::Dependencies() virtual — declare service deps; App initialises in topological order, deinitialises in reverse
• Cycles or unknown dependencies abort early
• App::TopoSortServices() exposed for unit tests

Utils

• xtils/utils/crypto.h — SHA-256, HMAC-SHA1/256, secure RNG, UUID v4 (reuses the selected TLS backend; no new deps)
• xtils/utils/result.h — Result<T,E> gains is_err(), unwrap_or_else(), expect(). Error model documented at docs/error-model.md in the source repo
• JSON: zero-copy find(key)/find(index), Json::object()/Json::array() factories; UTF-16 surrogate-pair fix; float round-trip precision (%.17g); operator[]/push_back type safety (only null may be promoted)

FSM / Behavior Tree

• FSM: HistoryEntry gains human-readable names, DumpHistory(), RegisterEvent/GetEventName. History is now a deque; recursive_mutex; GetHistory() returns by value; SetRecordFailedEvents(bool)
• BT: SubTree / WaitForEvent / EventGuard nodes; event queue (sendEvent/peekEvent/consumeEvent/hasEvent/clearEvents); pause/resume; LoadTreesFromDirectory; structured BtLogger (BtFileLogger/BtInspectLogger/BtCompositeLogger)

IPC (final v2.0 push)

• IpcServer / IpcClient reuse UnixSocketRaw and accept stream addresses beyond filesystem Unix sockets — abstract Unix and TCP IPv4/IPv6 also work
• TaskGroup is now the only IPC executor API; method/notification handlers dispatch through the server TaskGroup instead of running inline on per-client read threads
• Async calls no longer spawn one detached waiter thread each; callbacks complete from the read loop and are posted via the explicit / shared callback TaskGroup
• Pending callers and the read thread are correctly woken / joined when the peer disconnects before Disconnect()

Inspect

• Reimplementation: ~880 → ~330 lines
• Built-in two-pane web console (HTTP + WebSocket panels) embedded at build time via cmake/embed_file.cmake
• Handler signature: void(const Request&, Response&)
• New: PublishWithResult, GetSubscriberCount, GetRoutes, HasRoute

Notable fixes

• string_utils: rename misnamed parameter xtils back to base in every Int*ToString / StringToInt* overload
• App::Run(): replace broken heartbeat watchdog with proper monotonic deadline; accept threads=1
• EventManager::Stop: no longer shuts down a borrowed executor; default-constructed manager owns its own
• UnixSocketRaw::Receive/Send vs Shutdown race fixed with fd-validity check
• HttpRouter: per-request CORS reset on keep-alive; no dangling Origin string_view; no chunked trailer appended to response body

Migration

Item	How to migrate
All *_compat.h headers	Already removed — switch to PascalCase API
XTILS_ENABLE_DEPRECATED	Drop from CMake/build
HttpRequest/HttpResponse public types	Use HttpRouter::Context/Response (router) or HttpClient::Request/Response (client)
HttpClient::Request* sync entry points	Use HttpClient::Send()
WebSocketClient HttpClient dependency	No longer needed; client handles upgrade itself
IpcServer/IpcClient TaskRunner* ctor	Pass TaskGroup& (or rely on default shared TaskGroup)

---

v1.1.0 2025-10-16

First official tag. Includes all foundational modules built since project inception.

Module overview

Module	Status
App framework	✅ service lifecycle, events, timers
Config	✅ JSON config + CLI parsing
Logging	✅ async logger, console/file sinks, watchdog
Net	✅ TCP/UDP client/server, HTTP client/server, WebSocket client
FSM	✅ state machine + history + Graphviz export
Tasks	✅ event loop, thread pool, TaskGroup, timer, CronScheduler
Debug	✅ Inspect HTTP/WS debug server, Chrome Tracer
Utils	✅ JSON, strings, files, base64, SHA1, byte reader/writer

Highlights

• App framework: singleton context, Service<T> CRTP base, automatic config-section injection
• Event loop: epoll-backed UnixTaskRunner, ThreadTaskRunner dedicated-thread wrapper
• Networking: full TCP/UDP/HTTP/WebSocket stack, Express-style router, CORS, middleware
• Logging: printf-style macros, async ring buffer, size-rotated file sink, memory/CPU watchdog
• FSM: named states, event transitions, guards, history, DOT graph export
• CronScheduler: cron expressions + interval scheduling
• Custom JSON: zero-dependency, replaces nlohmann_json
• Inspect: runtime HTTP/WebSocket debug server, fully strippable at compile time
• Tracer: Chrome trace format profiling with RAII macros
• Build: single-static-library CMake target, automatic C++17 propagation, GitHub Actions CI

---

Project bootstrapping (2025-06 ~ 2025-09)

Initial phase, gradually building out core modules:

• 2025-06: HTTP / WebSocket server prototypes, JSON impl, Config class
• 2025-07: Inspect debug server, Tracer, WeakPtr, platform abstraction
• 2025-08: file utils, byte reader/writer, Service framework
• 2025-09: FSM debug enhancements, full HTTP/TCP/UDP impl