schematics/src/setup/runnable.rs

use super::SymbolRunner;
use crate::symbols::Symbol;
use async_trait::async_trait;
use slog::Logger;
use std::error::Error;
use std::fmt::Debug;

// A generalization over symbols and tuples of symbols
#[async_trait(?Send)]
pub trait Runnable {
  async fn run<R: SymbolRunner>(
    &self,
    runner: &R,
    logger: &Logger,
    force: bool,
  ) -> Result<bool, Box<dyn Error>>;
}

#[async_trait(?Send)]
#[allow(clippy::use_self)]
impl<S> Runnable for S
where
  Self: Symbol + Debug,
{
  async fn run<R: SymbolRunner>(
    &self,
    runner: &R,
    logger: &Logger,
    force: bool,
  ) -> Result<bool, Box<dyn Error>> {
    runner.run_symbol(self, logger, force).await
  }
}

macro_rules! runnable_for_tuple {
  ( $($name:ident)* ) => (
    #[allow(clippy::let_unit_value)]
    #[async_trait(?Send)]
    #[allow(non_snake_case)]
    impl<$($name: Symbol + Debug,)*> Runnable for ($($name,)*) {
      #[allow(unused)]
      async fn run<_R: SymbolRunner>(&self, runner: &_R, logger: &Logger, force: bool) -> Result<bool, Box<dyn Error>> {
        let ($($name,)*) = self;
        let mut result = false;
        $(result = runner.run_symbol($name, logger, force || result).await? || result;)*
        Ok(result)
      }
    }
  );
}

for_each_tuple!(runnable_for_tuple);

#[cfg(test)]
mod test {
  use super::super::symbol_runner::TestSymbolRunner;
  use super::Runnable;
  use crate::async_utils::run;
  use crate::symbols::Symbol;
  use async_trait::async_trait;
  use slog::{o, Discard, Logger};
  use std::cell::RefCell;
  use std::error::Error;
  use std::fmt::Debug;
  use std::rc::Rc;

  #[derive(Debug)]
  struct DummySymbol<T, E> {
    _target_reached: RefCell<T>,
    _execute: RefCell<E>,
  }

  #[async_trait(?Send)]
  impl<
      E: Iterator<Item = Result<(), Box<dyn Error>>>,
      T: Iterator<Item = Result<bool, Box<dyn Error>>>,
    > Symbol for DummySymbol<T, E>
  {
    async fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
      self._target_reached.borrow_mut().next().unwrap()
    }
    async fn execute(&self) -> Result<(), Box<dyn Error>> {
      self._execute.borrow_mut().next().unwrap()
    }
  }

  impl<
      E: Iterator<Item = Result<(), Box<dyn Error>>>,
      T: Iterator<Item = Result<bool, Box<dyn Error>>>,
    > DummySymbol<T, E>
  {
    fn new<
      IE: IntoIterator<IntoIter = E, Item = Result<(), Box<dyn Error>>>,
      IT: IntoIterator<IntoIter = T, Item = Result<bool, Box<dyn Error>>>,
    >(
      target_reached: IT,
      execute: IE,
    ) -> Self {
      Self {
        _target_reached: RefCell::new(target_reached.into_iter()),
        _execute: RefCell::new(execute.into_iter()),
      }
    }
  }

  fn run_symbol(
    runnable: impl Runnable,
    force: bool,
  ) -> (Rc<RefCell<usize>>, Result<bool, Box<dyn Error>>) {
    let (count, runner) = TestSymbolRunner::new();
    let res = run(runnable.run(&runner, &Logger::root(Discard, o!()), force));
    (count, res)
  }

  #[test]
  fn correctly_handles_symbol_tuples() {
    let (count, res) = run_symbol(
      (
        DummySymbol::new(vec![Ok(false)], vec![Ok(())]),
        DummySymbol::new(vec![Ok(false)], vec![Ok(())]),
      ),
      false,
    );
    res.unwrap();
    assert_eq!(*count.borrow(), 2);

    let (count, res) = run_symbol(
      (
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
        DummySymbol::new(vec![Ok(false)], vec![Ok(())]),
      ),
      false,
    );
    res.unwrap();
    assert_eq!(*count.borrow(), 1);

    // An unreached symbol forces all further symbols
    let (count, res) = run_symbol(
      (
        DummySymbol::new(vec![Ok(false)], vec![Ok(())]),
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
      ),
      false,
    );
    res.unwrap();
    assert_eq!(*count.borrow(), 2);

    let (count, res) = run_symbol(
      (
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
      ),
      false,
    );
    res.unwrap();
    assert_eq!(*count.borrow(), 0);

    let (count, res) = run_symbol(
      (
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
        DummySymbol::new(vec![Ok(true)], vec![Ok(())]),
      ),
      true,
    );
    res.unwrap();
    assert_eq!(*count.borrow(), 2);
  }
}