//! Stage 20: timerfd (timerfd_create / settime / gettime), checked by a
//! musl program (user/timerfdtest.c): one-shot, interval counts adding up,
//! non-blocking EAGAIN, poll/select/epoll wake-ups, and closing timerfds
//! leaves no timer and no memory behind.
#![no_std]
#![no_main]
#![feature(custom_test_frameworks)]
#![test_runner(rustbelt::test_runner)]
#![reexport_test_harness_main = "test_main"]

extern crate alloc;

use alloc::string::String;
use alloc::sync::Arc;
use alloc::vec::Vec;
use bootloader::{BootInfo, entry_point};
use core::panic::PanicInfo;
use rustbelt::fs::file::File;
use rustbelt::process::{self, ExitStatus, SpawnArgs};
use rustbelt::{fs, memory, thread, timer};

entry_point!(main);

fn main(boot_info: &'static BootInfo) -> ! {
    rustbelt::init();
    rustbelt::init_memory(boot_info);
    rustbelt::init_smp();
    fs::init();
    rustbelt::init_storage();
    test_main();
    rustbelt::hlt_loop();
}

/// Run /mnt/disk0/bin/`name` with `args`; its exit status and stdout.
fn run(name: &str, args: &[&str]) -> (ExitStatus, String) {
    let (reader, writer) = fs::pipe::new();
    let mut spawn = SpawnArgs::kernel(name);
    spawn.args.extend(args.iter().map(|a| String::from(*a)));
    spawn.stdio[1] = Arc::new(writer);
    let p = process::spawn_path(&alloc::format!("/mnt/disk0/bin/{}", name), spawn).expect("spawn failed");
    let mut out = Vec::new();
    let mut buf = [0u8; 256];
    loop {
        match reader.read(&mut buf).unwrap() {
            0 => break,
            n => out.extend_from_slice(&buf[..n]),
        }
    }
    (process::wait(&p), String::from_utf8_lossy(&out).into_owned())
}

fn counts() -> (usize, usize, usize) {
    thread::sleep_ticks(3);
    (thread::thread_count(), process::count(), memory::frames_in_use())
}

/// Everything in timerfdtest passes, twice; the second run leaves exactly
/// what was there before (the first one starts timerd, a kernel thread).
#[test_case]
fn timerfd_program_passes() {
    let (status, out) = run("timerfdtest", &[]);
    assert_eq!(status, ExitStatus::Exited(0), "output: {}", out);
    assert!(out.contains("timerfdtest: 0 failed"), "output: {}", out);
    let (timers, before) = (timer::count(), counts());
    let (status, out) = run("timerfdtest", &[]);
    assert_eq!(status, ExitStatus::Exited(0), "output: {}", out);
    assert_eq!(timer::count(), timers, "a closed timerfd left its timer behind");
    assert_eq!(counts(), before, "timerfdtest leaked something");
}

/// Kernel side: a timerfd's timer lives exactly as long as the file.
#[test_case]
fn timerfd_timer_goes_with_the_file() {
    let before = timer::count();
    let fd = timer::timerfd_new(timer::CLOCK_MONOTONIC, true);
    assert_eq!(timer::count(), before + 1);
    fd.settime(false, 60_000, 60_000);
    let mut buf = [0u8; 8];
    assert_eq!(fd.read(&mut buf[..4]), Err(rustbelt::errno::Errno::EINVAL));
    thread::sleep_ticks(6); // ~330 ms: several periods
    assert_eq!(fd.read(&mut buf), Ok(8));
    assert!(u64::from_le_bytes(buf) >= 2, "count {}", u64::from_le_bytes(buf));
    drop(fd);
    assert_eq!(timer::count(), before);
}

#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    rustbelt::test_panic_handler(info)
}