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#![feature(conservative_impl_trait)]
extern crate failure;
use failure::Error;
use std::marker::PhantomData;
use std::sync::{Arc, Weak, Mutex};
use std::thread;
pub trait Emitter: Send {
type input;
fn emit_arc(&mut self, Arc<Self::input>);
fn emit(&mut self, Self::input);
}
type Am<T> = Arc<Mutex<T>>;
type Wm<T> = Weak<Mutex<T>>;
pub trait SigFn<I, O>: Fn(&I) -> Result<O, Error> {}
impl<F, I, O> SigFn<I, O> for F where F: Fn(&I) -> Result<O, Error> {}
impl<I,O,F> Emitter for Signal<I,O,F>
where F: SigFn<I, O> + Send,
O: 'static + PartialEq + Send + Sync,
I: Send
{
type input = I;
fn emit(&mut self, data: Self::input) {
self.emit_arc(Arc::new(data));
}
fn emit_arc(&mut self, data: Arc<Self::input> ) {
let data_copy = data.clone();
let output = self.arc_wrapper_func(data_copy);
match output {
Ok(output) => {
if *self.output != *output {
self.output = output;
self.emit_children();
}
},
Err(e) => println!("Error: {:?}", e),
};
}
}
pub struct Signal<I, O, F>
where F: SigFn<I, O>
{
input: PhantomData<I>,
output: Arc<O>,
func: F,
listeners: Vec< Wm<Emitter<input=O>> >,
threaded_listeners: Vec< Wm<Emitter<input=O>> >,
}
impl<I,O,F> Signal<I,O,F>
where F: SigFn<I, O>,
O: 'static + Send + Sync
{
pub fn new(f: F) -> Am<Signal<I, O, impl SigFn<I, O>>>
where F: SigFn<I, O>,
O: Default
{
Arc::new(Mutex::new(Signal {
input: PhantomData,
output: Default::default(),
func: move |i: &_| f(i),
listeners: Vec::new(),
threaded_listeners: Vec::new(),
}))
}
fn arc_wrapper_func(&self, input: Arc<I>) -> Result<Arc<O>, Error> {
Ok(Arc::new((self.func)(&(*input))?))
}
fn emit_children(&mut self) {
for signal in self.listeners.iter_mut() {
if let Some(signal) = signal.upgrade() {
let output_copy = self.output.clone();
if let Ok(mut signal) = signal.lock() {
signal.emit_arc(output_copy);
}
}
}
for signal in self.threaded_listeners.iter_mut() {
let weak_sig = signal.clone();
let output_copy = self.output.clone();
thread::spawn( move || {
if let Some(signal) = weak_sig.upgrade() {
if let Ok(mut signal) = signal.lock() {
signal.emit_arc(output_copy);
}
}
});
}
}
pub fn create_listener<Q, G>(&mut self, f: G) -> Arc<Mutex<Signal<O, Q, impl SigFn<O,Q>>>>
where G: 'static + SigFn<O,Q> + Send,
Q: 'static + Default + PartialEq + Send + Sync,
O: 'static
{
let ret = Signal::new(f);
self.register_listener(&ret);
ret
}
pub fn create_threaded_listener<Q, G>(&mut self, f: G) -> Arc<Mutex<Signal<O, Q, impl SigFn<O,Q>>>>
where G: 'static + SigFn<O,Q> + Send,
Q: 'static + Default + PartialEq + Send + Sync,
O: 'static
{
let ret = Signal::new(f);
self.register_threaded_listener(&ret);
ret
}
pub fn register_listener<S>(&mut self, strong: &Arc<Mutex<S>>)
where S: 'static + Emitter<input=O>
{
let weak = Arc::downgrade(&strong);
self.listeners.push(weak);
}
pub fn register_threaded_listener<S>(&mut self, strong: &Arc<Mutex<S>>)
where S: 'static + Emitter<input=O>
{
let weak = Arc::downgrade(&strong);
self.threaded_listeners.push(weak);
}
pub fn get(&self) -> Arc<O> { self.output.clone() }
}
#[cfg(test)]
mod tests {
#[test]
fn it_works() {
assert_eq!(2 + 2, 4);
}
}