Return view on pop_layer

Callbacks now often allow (and ignore) a return type.

src/cursive.rs

@@ -394,9 +394,10 @@ impl Cursive {
     }
 
     /// Convenient method to remove a layer from the current screen.
-    pub fn pop_layer(&mut self) {
-        self.screen_mut().pop_layer();
+    pub fn pop_layer(&mut self) -> Option<Box<View>> {
+        let result = self.screen_mut().pop_layer();
         self.clear();
+        result
     }
 
     // Handles a key event when it was ignored by the current view

src/event.rs

@@ -27,8 +27,13 @@ pub struct Callback(Rc<Box<Fn(&mut Cursive)>>);
 
 impl Callback {
     /// Wraps the given function into a `Callback` object.
-    pub fn from_fn<F: Fn(&mut Cursive) + 'static>(f: F) -> Self {
-        Callback(Rc::new(Box::new(f)))
+    pub fn from_fn<F, R>(f: F) -> Self
+    where
+        F: 'static + Fn(&mut Cursive) -> R,
+    {
+        Callback(Rc::new(Box::new(move |siv| {
+            f(siv);
+        })))
     }
 }
 
@@ -68,7 +73,10 @@ pub enum EventResult {
 
 impl EventResult {
     /// Convenient method to create `Consumed(Some(f))`
-    pub fn with_cb<F: 'static + Fn(&mut Cursive)>(f: F) -> Self {
+    pub fn with_cb<F, R>(f: F) -> Self
+    where
+        F: 'static + Fn(&mut Cursive) -> R,
+    {
         EventResult::Consumed(Some(Callback::from_fn(f)))
     }
 
@@ -245,9 +253,9 @@ impl MouseEvent {
     /// Returns `None` if `self` is `WheelUp` or `WheelDown`.
     pub fn button(&self) -> Option<MouseButton> {
         match *self {
-            MouseEvent::Press(btn) |
-            MouseEvent::Release(btn) |
-            MouseEvent::Hold(btn) => Some(btn),
+            MouseEvent::Press(btn)
+            | MouseEvent::Release(btn)
+            | MouseEvent::Hold(btn) => Some(btn),
             _ => None,
         }
     }
@@ -257,9 +265,9 @@ impl MouseEvent {
     /// This includes `Press`, `WheelUp` and `WheelDown`.
     pub fn grabs_focus(self) -> bool {
         match self {
-            MouseEvent::Press(_) |
-            MouseEvent::WheelUp |
-            MouseEvent::WheelDown => true,
+            MouseEvent::Press(_)
+            | MouseEvent::WheelUp
+            | MouseEvent::WheelDown => true,
             _ => false,
         }
     }

src/views/button.rs

@@ -27,18 +27,18 @@ pub struct Button {
 
 impl Button {
     /// Creates a new button with the given content and callback.
-    pub fn new<F, S: Into<String>>(label: S, cb: F) -> Self
+    pub fn new<F, R, S: Into<String>>(label: S, cb: F) -> Self
     where
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         let label = label.into();
         Self::new_raw(format!("<{}>", label), cb)
     }
 
     /// Creates a new button without angle brackets.
-    pub fn new_raw<F, S: Into<String>>(label: S, cb: F) -> Self
+    pub fn new_raw<F, R, S: Into<String>>(label: S, cb: F) -> Self
     where
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         Button {
             label: label.into(),

src/views/dialog.rs

@@ -25,9 +25,9 @@ struct ChildButton {
 }
 
 impl ChildButton {
-    pub fn new<F, S: Into<String>>(label: S, cb: F) -> Self
+    pub fn new<F, R, S: Into<String>>(label: S, cb: F) -> Self
     where
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         ChildButton {
             button: SizedView::new(Button::new(label, cb)),
@@ -125,9 +125,9 @@ impl Dialog {
     /// Adds a button to the dialog with the given label and callback.
     ///
     /// Consumes and returns self for easy chaining.
-    pub fn button<F, S: Into<String>>(mut self, label: S, cb: F) -> Self
+    pub fn button<F, R, S: Into<String>>(mut self, label: S, cb: F) -> Self
     where
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         self.buttons.push(ChildButton::new(label, cb));
 
@@ -158,7 +158,7 @@ impl Dialog {
 
     /// Shortcut method to add a button that will dismiss the dialog.
     pub fn dismiss_button<S: Into<String>>(self, label: S) -> Self {
-        self.button(label, |s| s.screen_mut().pop_layer())
+        self.button(label, |s| s.pop_layer())
     }
 
     /// Sets the title of the dialog.
@@ -226,9 +226,9 @@ impl Dialog {
         ) {
             EventResult::Ignored if !self.buttons.is_empty() => {
                 match event {
-                    Event::Key(Key::Down) |
-                    Event::Key(Key::Tab) |
-                    Event::Shift(Key::Tab) => {
+                    Event::Key(Key::Down)
+                    | Event::Key(Key::Tab)
+                    | Event::Shift(Key::Tab) => {
                         // Default to leftmost button when going down.
                         self.focus = Focus::Button(0);
                         EventResult::Consumed(None)
@@ -365,7 +365,9 @@ impl Dialog {
                 return;
             }
             let spacing = 3; //minimum distance to borders
-            let x = spacing + self.title_position.get_offset(len, printer.size.x - 2 * spacing);
+            let x = spacing
+                + self.title_position
+                    .get_offset(len, printer.size.x - 2 * spacing);
             printer.with_high_border(false, |printer| {
                 printer.print((x - 2, 0), "┤ ");
                 printer.print((x + len, 0), " ├");

src/views/menu_popup.rs

@@ -1,5 +1,3 @@
-
-
 use Cursive;
 use Printer;
 use With;
@@ -376,8 +374,8 @@ impl View for MenuPopup {
                     }
                 }
             }
-            Event::Key(Key::Esc) |
-            Event::Mouse {
+            Event::Key(Key::Esc)
+            | Event::Mouse {
                 event: MouseEvent::Press(_),
                 ..
             } => {

src/views/on_event_view.rs

@@ -77,10 +77,10 @@ impl<T: View> OnEventView<T> {
     /// 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
+    pub fn on_event<F, R, E>(self, event: E, cb: F) -> Self
     where
         E: Into<Event>,
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         self.with(|s| s.set_on_event(event, cb))
     }
@@ -90,10 +90,10 @@ impl<T: View> OnEventView<T> {
     /// The child will never receive this event.
     ///
     /// Chainable variant.
-    pub fn on_pre_event<F, E>(self, event: E, cb: F) -> Self
+    pub fn on_pre_event<F, R, E>(self, event: E, cb: F) -> Self
     where
         E: Into<Event>,
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         self.with(|s| s.set_on_pre_event(event, cb))
     }
@@ -132,10 +132,10 @@ impl<T: View> OnEventView<T> {
     }
 
     /// 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)
+    pub fn set_on_event<F, R, E>(&mut self, event: E, cb: F)
     where
         E: Into<Event>,
-        F: Fn(&mut Cursive) + 'static,
+        F: Fn(&mut Cursive) -> R + 'static,
     {
         let cb = Callback::from_fn(cb);
         let action =
@@ -147,12 +147,13 @@ impl<T: View> OnEventView<T> {
     /// 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)
+    pub fn set_on_pre_event<F, R, E>(&mut self, event: E, cb: F)
     where
         E: Into<Event>,
-        F: Fn(&mut Cursive) + 'static,
+        F: 'static + Fn(&mut Cursive) -> R,
     {
         let cb = Callback::from_fn(cb);
+        // We want to clone the Callback every time we call the closure
         let action =
             move |_: &mut T| Some(EventResult::Consumed(Some(cb.clone())));
 

src/views/select_view.rs

@@ -152,12 +152,14 @@ impl<T: 'static> SelectView<T> {
     /// The item currently selected will be given to the callback.
     ///
     /// Here, `V` can be `T` itself, or a type that can be borrowed from `T`.
-    pub fn set_on_submit<F, V: ?Sized>(&mut self, cb: F)
+    pub fn set_on_submit<F, R, V: ?Sized>(&mut self, cb: F)
     where
-        F: Fn(&mut Cursive, &V) + 'static,
+        F: 'static + Fn(&mut Cursive, &V) -> R,
         T: Borrow<V>,
     {
-        self.on_submit = Some(Rc::new(move |s, t| cb(s, t.borrow())));
+        self.on_submit = Some(Rc::new(move |s, t| {
+            cb(s, t.borrow());
+        }));
     }
 
     /// Sets a callback to be used when `<Enter>` is pressed.

src/views/stack_view.rs

@@ -6,7 +6,7 @@ use std::any::Any;
 use std::ops::Deref;
 use theme::ColorStyle;
 use vec::Vec2;
-use view::{Offset, Position, Selector, View};
+use view::{Offset, Position, Selector, View, ViewWrapper};
 use views::{Layer, ShadowView};
 
 /// Simple stack of views.
@@ -47,9 +47,20 @@ enum ChildWrapper<T: View> {
     Plain(Layer<T>),
 }
 
+impl<T: View> ChildWrapper<T> {
+    fn unwrap(self) -> T {
+        match self {
+            // ShadowView::into_inner and Layer::into_inner can never fail.
+            ChildWrapper::Shadow(shadow) => {
+                shadow.into_inner().ok().unwrap().into_inner().ok().unwrap()
+            }
+            ChildWrapper::Plain(layer) => layer.into_inner().ok().unwrap(),
+        }
+    }
+}
+
 // TODO: use macros to make this less ugly?
 impl<T: View> View for ChildWrapper<T> {
-
     fn draw(&self, printer: &Printer) {
         match *self {
             ChildWrapper::Shadow(ref v) => v.draw(printer),
@@ -86,12 +97,15 @@ impl <T: View> View for ChildWrapper<T> {
     }
 
     fn call_on_any<'a>(
-        &mut self, selector: &Selector,
-        callback: Box<FnMut(&mut Any) + 'a>,
+        &mut self, selector: &Selector, callback: Box<FnMut(&mut Any) + 'a>
     ) {
         match *self {
-            ChildWrapper::Shadow(ref mut v) => v.call_on_any(selector, callback),
-            ChildWrapper::Plain(ref mut v) => v.call_on_any(selector, callback),
+            ChildWrapper::Shadow(ref mut v) => {
+                v.call_on_any(selector, callback)
+            }
+            ChildWrapper::Plain(ref mut v) => {
+                v.call_on_any(selector, callback)
+            }
         }
     }
 
@@ -101,7 +115,6 @@ impl <T: View> View for ChildWrapper<T> {
             ChildWrapper::Plain(ref mut v) => v.focus_view(selector),
         }
     }
-
 }
 
 struct Child {
@@ -201,8 +214,8 @@ impl StackView {
     }
 
     /// Remove the top-most layer.
-    pub fn pop_layer(&mut self) {
-        self.layers.pop();
+    pub fn pop_layer(&mut self) -> Option<Box<View>> {
+        self.layers.pop().map(|child| child.view.unwrap())
     }
 
     /// Computes the offset of the current top view.