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use Cursive;
use With;
use event::{Callback, Event, EventResult};
use std::collections::HashMap;
use std::rc::Rc;
use view::{View, ViewWrapper};
/// A simple wrapper view that catches some ignored event from its child.
///
/// If the event doesn't have a corresponding callback, it will stay ignored.
///
/// # Examples
///
/// ```
/// # use cursive::event;;
/// # use cursive::views::{OnEventView, TextView};
/// let view = OnEventView::new(TextView::new("This view has an event!"))
/// .on_event('q', |s| s.quit())
/// .on_event(event::Key::Esc, |s| s.quit());
/// ```
pub struct OnEventView<T: View> {
inner: T,
callbacks: HashMap<Event, Action<T>>,
}
type InnerCallback<T> = Rc<Box<Fn(&mut T) -> Option<EventResult>>>;
struct Action<T> {
phase: TriggerPhase,
callback: InnerCallback<T>,
}
impl<T> Clone for Action<T> {
fn clone(&self) -> Self {
Action {
phase: self.phase.clone(),
callback: Rc::clone(&self.callback),
}
}
}
#[derive(PartialEq, Clone)]
enum TriggerPhase {
BeforeChild,
AfterChild,
}
impl<T: View> OnEventView<T> {
/// Wraps the given view in a new OnEventView.
pub fn new(view: T) -> Self {
OnEventView {
inner: view,
callbacks: HashMap::new(),
}
}
/// Registers a callback when the given event is ignored by the child.
///
/// Chainable variant.
pub fn on_event<F, E>(self, event: E, cb: F) -> Self
where
E: Into<Event>,
F: Fn(&mut Cursive) + 'static,
{
self.with(|s| s.set_on_event(event, cb))
}
/// Registers a callback when the given event is received.
///
/// The child will never receive this event.
///
/// Chainable variant.
pub fn on_pre_event<F, E>(self, event: E, cb: F) -> Self
where
E: Into<Event>,
F: Fn(&mut Cursive) + 'static,
{
self.with(|s| s.set_on_pre_event(event, cb))
}
/// Registers a callback when the given event is received.
///
/// The given callback will be run before the child view sees the event.
/// If the result is `None`, then the child view is given the event as usual.
/// Otherwise, it bypasses the child view and directly processes the result.
///
/// Chainable variant.
pub fn on_pre_event_inner<F, E>(self, event: E, cb: F) -> Self
where
E: Into<Event>,
F: Fn(&mut T) -> Option<EventResult> + 'static,
{
self.with(|s| s.set_on_pre_event_inner(event, cb))
}
/// Registers a callback when the given event is ignored by the child.
///
/// If the child view ignores the event, `cb` will be called with the
/// child view as argument.
/// If the result is not `None`, it will be processed as well.
///
/// Chainable variant.
pub fn on_event_inner<F, E>(self, event: E, cb: F) -> Self
where
E: Into<Event>,
F: Fn(&mut T) -> Option<EventResult> + 'static,
{
self.with(|s| s.set_on_event_inner(event, cb))
}
/// Registers a callback when the given event is ignored by the child.
pub fn set_on_event<F, E>(&mut self, event: E, cb: F)
where
E: Into<Event>,
F: Fn(&mut Cursive) + 'static,
{
let cb = Callback::from_fn(cb);
let action =
move |_: &mut T| Some(EventResult::Consumed(Some(cb.clone())));
self.set_on_event_inner(event, action);
}
/// Registers a callback when the given event is received.
///
/// The child will never receive this event.
pub fn set_on_pre_event<F, E>(&mut self, event: E, cb: F)
where
E: Into<Event>,
F: Fn(&mut Cursive) + 'static,
{
let cb = Callback::from_fn(cb);
let action =
move |_: &mut T| Some(EventResult::Consumed(Some(cb.clone())));
self.set_on_pre_event_inner(event, action);
}
/// Registers a callback when the given event is received.
///
/// The given callback will be run before the child view sees the event.
/// If the result is `None`, then the child view is given the event as usual.
/// Otherwise, it bypasses the child view and directly processes the result.
pub fn set_on_pre_event_inner<F, E>(&mut self, event: E, cb: F)
where
E: Into<Event>,
F: Fn(&mut T) -> Option<EventResult> + 'static,
{
self.callbacks.insert(
event.into(),
Action {
phase: TriggerPhase::BeforeChild,
callback: Rc::new(Box::new(cb)),
},
);
}
/// Registers a callback when the given event is ignored by the child.
///
/// If the child view ignores the event, `cb` will be called with the
/// child view as argument.
/// If the result is not `None`, it will be processed as well.
pub fn set_on_event_inner<F, E>(&mut self, event: E, cb: F)
where
E: Into<Event>,
F: Fn(&mut T) -> Option<EventResult> + 'static,
{
self.callbacks.insert(
event.into(),
Action {
phase: TriggerPhase::AfterChild,
callback: Rc::new(Box::new(cb)),
},
);
}
}
impl<T: View> ViewWrapper for OnEventView<T> {
wrap_impl!(self.inner: T);
fn wrap_on_event(&mut self, event: Event) -> EventResult {
let action = self.callbacks.get(&event).cloned();
let pre_child = action
.as_ref()
.map(|a| a.phase == TriggerPhase::BeforeChild)
.unwrap_or(false);
if pre_child {
action
.and_then(|a| (*a.callback)(&mut self.inner))
.unwrap_or_else(|| self.inner.on_event(event))
} else {
self.inner.on_event(event).or_else(|| {
action
.and_then(|a| (*a.callback)(&mut self.inner))
.unwrap_or(EventResult::Ignored)
})
}
}
}