init

pub fn init(ev: *Evented, backing_allocator: Allocator, options: InitOptions) !void {
    const threads_size = @sizeOf(Thread) * if (options.thread_limit) |thread_limit|
        1 + thread_limit
    else
        @max(std.Thread.getCpuCount() catch 1, 1);
    const idle_stack_end_offset =
        std.mem.alignForward(usize, threads_size + idle_stack_size, std.heap.pageSize());
    const allocated_slice = try backing_allocator.alignedAlloc(u8, .of(Thread), idle_stack_end_offset);
    errdefer backing_allocator.free(allocated_slice);
    ev.* = .{
        .backing_allocator_needs_mutex = options.backing_allocator_needs_mutex,
        .backing_allocator_mutex = .init,
        .backing_allocator = backing_allocator,
        .main_fiber_buffer = undefined,
        .log2_ring_entries = options.log2_ring_entries,
        .threads = .{
            .allocated = @ptrCast(allocated_slice[0..threads_size]),
            .reserved = 1,
            .active = 1,
        },
        .sync_limit = if (options.sync_limit.toInt()) |sync_limit| .{ .permits = sync_limit } else null,

        .stderr_writer_initialized = false,
        .stderr_mutex = .init,
        .stderr_writer = .{
            .io = ev.io(),
            .interface = Io.File.Writer.initInterface(&.{}),
            .file = .stderr(),
            .mode = .streaming,
        },
        .stderr_mode = .no_color,

        .environ_mutex = .init,
        .environ_initialized = options.environ.block.isEmpty(),
        .environ = .{ .process_environ = options.environ },

        .null_fd = .init,
        .random_fd = .init,

        .csprng_mutex = .init,
        .csprng = .uninitialized,
    };
    const main_fiber: *Fiber = @ptrCast(&ev.main_fiber_buffer);
    main_fiber.* = .{
        .required_align = {},
        .context = undefined,
        .link = .{ .awaiter = null },
        .status = .{ .queue_next = null },
        .cancel_status = .unrequested,
        .cancel_protection = .unblocked,
        .name = if (tracy.enable) "main task",
    };
    const main_thread = &ev.threads.allocated[0];
    Thread.self = main_thread;
    main_thread.* = .{
        .required_align = {},
        .thread = undefined,
        .idle_context = switch (builtin.cpu.arch) {
            .aarch64 => .{
                .sp = @intFromPtr(allocated_slice[idle_stack_end_offset..].ptr),
                .fp = @intFromPtr(ev),
                .pc = @intFromPtr(&mainIdleEntry),
            },
            .riscv64 => .{
                .sp = @intFromPtr(allocated_slice[idle_stack_end_offset..].ptr),
                .fp = @intFromPtr(ev),
                .pc = @intFromPtr(&mainIdleEntry),
            },
            .x86_64 => .{
                .rsp = @intFromPtr(allocated_slice[idle_stack_end_offset..].ptr),
                .rbp = @intFromPtr(ev),
                .rip = @intFromPtr(&mainIdleEntry),
            },
            else => @compileError("unimplemented architecture"),
        },
        .current_context = &main_fiber.context,
        .ready_queue = null,
        .free_queue = null,
        .io_uring = try .init(
            @as(u16, 1) << ev.log2_ring_entries,
            linux.IORING_SETUP_COOP_TASKRUN | linux.IORING_SETUP_SINGLE_ISSUER,
        ),
        .idle_search_index = 1,
        .steal_ready_search_index = 1,
        .steal_free_search_index = 1,
        .name_arena = .{},
        .csprng = .uninitialized,
    };
    errdefer main_thread.io_uring.deinit();
    if (tracy.enable) tracy.fiberEnter(main_fiber.name);
}