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use crate::event::{Callback, Event, EventResult, EventTrigger}; use crate::view::{View, ViewWrapper}; use crate::Cursive; use crate::With; use std::rc::Rc; /// A wrapper view that can react to events. /// /// This view registers a set of callbacks tied to specific events, to be run /// in certain conditions. /// /// * Some callbacks are called only for events ignored by the wrapped view. /// /// (those registered by [`on_event`] or [`on_event_inner`]) /// * Others are processed first, and can control whether the child view should /// be given the event (those registered by [`on_pre_event`] or /// [`on_pre_event_inner`]). /// /// "Inner" callbacks ([`on_event_inner`] and [`on_pre_event_inner`]) are given /// a reference to the inner wrapped view (but not to the `Cursive` root). They /// can then return another callback, taking only a `&mut Cursive` root as /// argument. /// /// "Simple" callbacks ([`on_event`] and [`on_pre_event`]) skip this first /// phase and are only called with a `&mut Cursive`. /// /// [`on_event`]: OnEventView::on_event /// [`on_pre_event`]: OnEventView::on_pre_event /// [`on_event_inner`]: OnEventView::on_event_inner /// [`on_pre_event_inner`]: OnEventView::on_pre_event_inner /// /// # Examples /// /// ``` /// # use cursive_core::event;; /// # use cursive_core::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: T, callbacks: Vec<(EventTrigger, Action<T>)>, } new_default!(OnEventView<T: Default>); type InnerCallback<T> = Rc<Box<dyn Fn(&mut T, &Event) -> 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> OnEventView<T> { /// Wraps the given view in a new OnEventView. pub fn new(view: T) -> Self { OnEventView { view, callbacks: Vec::new(), } } /// Remove all callbacks associated with the given event. pub fn clear_event<E>(&mut self, event: E) where E: Into<Event>, { let event = event.into(); self.callbacks .retain(move |&(ref trigger, _)| !trigger.has_tag(&event)); } /// Registers a callback when the given event is ignored by the child. /// /// Chainable variant. /// /// # Examples /// /// /// ```rust /// # use cursive_core::views::{OnEventView, DummyView}; /// # use cursive_core::event::{Key, EventTrigger}; /// let view = OnEventView::new(DummyView) /// .on_event('q', |s| s.quit()) /// .on_event(Key::Esc, |s| { /// s.pop_layer(); /// }) /// .on_event(EventTrigger::mouse(), |s| { /// s.add_layer(DummyView); /// }); /// ``` pub fn on_event<F, E>(self, trigger: E, cb: F) -> Self where E: Into<EventTrigger>, F: 'static + Fn(&mut Cursive), { self.with(|s| s.set_on_event(trigger, 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, trigger: E, cb: F) -> Self where E: Into<EventTrigger>, F: 'static + Fn(&mut Cursive), { self.with(|s| s.set_on_pre_event(trigger, 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, trigger: E, cb: F) -> Self where E: Into<EventTrigger>, F: Fn(&mut T, &Event) -> Option<EventResult> + 'static, { self.with(|s| s.set_on_pre_event_inner(trigger, cb)) } /// Registers a callback when the given event is ignored by the child. /// /// This is an advanced method to get more control. /// [`on_event`] may be easier to use. /// /// 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. /// /// [`on_event`]: OnEventView::on_event() /// /// # Examples /// /// ```rust /// # use cursive_core::views::{DummyView, OnEventView}; /// # use cursive_core::event::{Event, EventTrigger, MouseEvent, EventResult}; /// let view = OnEventView::new(DummyView) /// .on_event_inner( /// EventTrigger::mouse(), /// |d: &mut DummyView, e: &Event| { /// if let &Event::Mouse { event: MouseEvent::Press(_), .. } = e { /// // Do something on mouse press /// Some(EventResult::with_cb(|s| { /// s.pop_layer(); /// })) /// } else { /// // Otherwise, don't do anything /// None /// } /// } /// ); /// ``` pub fn on_event_inner<F, E>(self, trigger: E, cb: F) -> Self where E: Into<EventTrigger>, F: Fn(&mut T, &Event) -> Option<EventResult> + 'static, { self.with(|s| s.set_on_event_inner(trigger, cb)) } /// Registers a callback when the given event is ignored by the child. pub fn set_on_event<F, E>(&mut self, trigger: E, cb: F) where E: Into<EventTrigger>, F: Fn(&mut Cursive) + 'static, { let cb = Callback::from_fn(cb); let action = move |_: &mut T, _: &Event| { Some(EventResult::Consumed(Some(cb.clone()))) }; self.set_on_event_inner(trigger, 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, trigger: E, cb: F) where E: Into<EventTrigger>, F: 'static + Fn(&mut Cursive), { let cb = Callback::from_fn(cb); // We want to clone the Callback every time we call the closure let action = move |_: &mut T, _: &Event| { Some(EventResult::Consumed(Some(cb.clone()))) }; self.set_on_pre_event_inner(trigger, 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, trigger: E, cb: F) where E: Into<EventTrigger>, F: Fn(&mut T, &Event) -> Option<EventResult> + 'static, { self.callbacks.push(( trigger.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, trigger: E, cb: F) where E: Into<EventTrigger>, F: Fn(&mut T, &Event) -> Option<EventResult> + 'static, { self.callbacks.push(( trigger.into(), Action { phase: TriggerPhase::AfterChild, callback: Rc::new(Box::new(cb)), }, )); } /// Remove any callbacks defined for this view. pub fn clear_callbacks(&mut self) { self.callbacks.clear(); } inner_getters!(self.view: T); } impl<T: View> ViewWrapper for OnEventView<T> { wrap_impl!(self.view: T); fn wrap_on_event(&mut self, event: Event) -> EventResult { // Until we have better closure capture, define captured members separately. let callbacks = &self.callbacks; let view = &mut self.view; // * First, check all pre-child callbacks. Combine them. // If any gets triggered and returns Some(...), stop right there. // * Otherwise, give the event to the child view. // If it returns EventResult::Consumed, stop right there. // * Finally, check all post-child callbacks. Combine them. // And just return the result. // First step: check pre-child callbacks .iter() .filter(|&(_, action)| action.phase == TriggerPhase::BeforeChild) .filter(|&(trigger, _)| trigger.apply(&event)) .filter_map(|(_, action)| (*action.callback)(view, &event)) .fold(None, |s, r| match s { // Return `Some()` if any pre-callback was present. None => Some(r), Some(c) => Some(c.and(r)), }) .unwrap_or_else(|| { // If it was None, it means no pre-callback was triggered. // So let's give the view a chance! view.on_event(event.clone()) }) .or_else(|| { // No pre-child, and the child itself ignored the event? // Let's have a closer look then, shall we? callbacks .iter() .filter(|&(_, action)| { action.phase == TriggerPhase::AfterChild }) .filter(|&(trigger, _)| trigger.apply(&event)) .filter_map(|(_, action)| (*action.callback)(view, &event)) .fold(EventResult::Ignored, EventResult::and) }) } }