atproto relay implementation in zig
zlay.waow.tech
force Io.Threaded backend — fix SIGSEGV on startup
Evented (io_uring) futexWait/Wake dispatch through fiber-local
Thread.current() state. Frame pool workers are plain std.Thread —
they lack that state, so Io.Mutex contention segfaults immediately.
Threaded backend uses direct kernel futex syscalls that work from
any execution context. io.concurrent still spawns real OS threads
(same concurrency model as 0.15, just 0.16 APIs).
Evented can be revisited once frame workers either move to
io.concurrent or cross-boundary mutexes get a dedicated Threaded
sync_io.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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src/main.zig
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src/main.zig
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pub const default_stack_size = 8 * 1024 * 1024;
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// -- Io backend selection --
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// Evented = Io.Uring (linux) | Io.Dispatch (macOS) | Io.Kqueue (BSD) | void
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// Falls back to Io.Threaded on platforms without fiber support.
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const Backend = if (Io.Evented != void) Io.Evented else Io.Threaded;
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// Evented backends (Io.Uring, Io.Dispatch, Io.Kqueue) use fiber-local state
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// for futex wait/wake. Plain std.Thread workers (frame pool) calling
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// Io.Mutex with an Evented io segfault because they lack that state.
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// Use Threaded until frame workers are migrated to io.concurrent or
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// cross-boundary mutexes get a dedicated Threaded sync_io.
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const Backend = Io.Threaded;
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var backend: Backend = undefined;
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var debug_threaded_io: Io.Threaded = undefined;