pistoncore-event 0.0.1

A library for flexible generic event threading
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use std::intrinsics::TypeId;

use input;

use {
    RenderArgs,
    RenderEvent,
    UpdateArgs,
    UpdateEvent,
    GenericEvent,
};
use Event::{ Render, Update, Input };
use ptr::Ptr;
use events::EventMap;

/// Adds render and update events to input events
#[deriving(Clone, PartialEq, Show)]
pub enum Event<I = input::Input> {
    /// Render graphics.
    Render(RenderArgs),
    /// Update the state of the application.
    Update(UpdateArgs),
    /// Input event.
    Input(I),
}

impl<I> EventMap<I> for Event<I> {
    fn render(args: RenderArgs) -> Event<I> { Render(args) }
    fn update(args: UpdateArgs) -> Event<I> { Update(args) }
    fn input(args: I) -> Event<I> { Input(args) }
}

impl<I: GenericEvent> GenericEvent for Event<I> {
    #[inline(always)]
    fn from_event(event_trait_id: TypeId, ev: &Ptr) -> Option<Event<I>> {
        let update = TypeId::of::<Box<UpdateEvent>>();
        let render = TypeId::of::<Box<RenderEvent>>();
        match event_trait_id {
            x if x == update => {
                Some(Update(ev.expect::<UpdateArgs>().clone()))
            }
            x if x == render => {
                Some(Render(ev.expect::<RenderArgs>().clone()))
            }
            _ => {
                let input: Option<I> = GenericEvent::from_event(
                    event_trait_id, ev
                );
                match input {
                    Some(input) => Some(Input(input)),
                    None => None
                }
            }
        }
    }

    #[inline(always)]
    fn with_event<U>(&self, event_trait_id: TypeId, f: |&Ptr| -> U) -> Option<U> {
        let update = TypeId::of::<Box<UpdateEvent>>();
        let render = TypeId::of::<Box<RenderEvent>>();
        match event_trait_id {
            x if x == update => {
                match *self {
                    Update(ref args) => Some(Ptr::with_ref(args, |ptr| f(ptr))),
                    _ => None
                }
            }
            x if x == render => {
                match *self {
                    Render(ref args) => Some(Ptr::with_ref(args, |ptr| f(ptr))),
                    _ => None
                }
            }
            _ => {
                match *self {
                    Input(ref input) => input.with_event(event_trait_id, f),
                    _ => None
                }
            }
        }
    }
}

#[test]
fn test_event() {
    use assert_event_trait;
    use MouseCursorEvent;

    // Update.
    let ref e = UpdateEvent::from_update_args(&UpdateArgs { dt: 1.0 }).unwrap();
    assert_event_trait::<Event, Box<UpdateEvent>>(e);

    // Render.
    let ref e = RenderEvent::from_render_args(
        &RenderArgs { ext_dt: 1.0, width: 0, height: 0 }
    ).unwrap();
    assert_event_trait::<Event, Box<RenderEvent>>(e);

    let ref e = MouseCursorEvent::from_xy(1.0, 0.0).unwrap();
    assert_event_trait::<Event, Box<MouseCursorEvent>>(e);
}