From 98aff399047dac4e9d1cc7897920472312001738 Mon Sep 17 00:00:00 2001
From: Alexandre Bury <alexandre.bury@gmail.com>
Date: Mon, 22 Jan 2018 11:50:25 -0800
Subject: [PATCH] Move `View::as_any` to separate trait `AnyView`

---
 examples/key_codes.rs      |  2 --
 examples/logs.rs           |  2 --
 src/cursive.rs             |  4 ++--
 src/view/mod.rs            | 31 +++++++++++++++++--------------
 src/view/view_wrapper.rs   | 18 ++++++++++++------
 src/views/button.rs        |  2 --
 src/views/canvas.rs        |  2 --
 src/views/checkbox.rs      |  2 --
 src/views/dialog.rs        |  6 ++----
 src/views/dummy.rs         |  2 --
 src/views/edit_view.rs     |  2 --
 src/views/linear_layout.rs | 13 +++++--------
 src/views/list_view.rs     | 25 +++++++++++++------------
 src/views/menu_popup.rs    |  2 --
 src/views/menubar.rs       |  2 --
 src/views/progress_bar.rs  |  2 --
 src/views/radio.rs         |  3 ---
 src/views/select_view.rs   |  2 --
 src/views/slider_view.rs   |  2 --
 src/views/stack_view.rs    | 14 +++++---------
 src/views/text_area.rs     |  2 --
 src/views/text_view.rs     |  2 --
 22 files changed, 56 insertions(+), 86 deletions(-)

diff --git a/examples/key_codes.rs b/examples/key_codes.rs
index 2b345b4..f628583 100644
--- a/examples/key_codes.rs
+++ b/examples/key_codes.rs
@@ -31,8 +31,6 @@ impl KeyCodeView {
 }
 
 impl View for KeyCodeView {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         // We simply draw every event from the history.
         for (y, line) in self.history.iter().enumerate() {
diff --git a/examples/logs.rs b/examples/logs.rs
index c1f33a0..83463dd 100644
--- a/examples/logs.rs
+++ b/examples/logs.rs
@@ -81,8 +81,6 @@ impl BufferView {
 }
 
 impl View for BufferView {
-    view_any!();
-
     fn layout(&mut self, _: Vec2) {
         // Before drawing, we'll want to update the buffer
         self.update();
diff --git a/src/cursive.rs b/src/cursive.rs
index e317498..7cb3286 100644
--- a/src/cursive.rs
+++ b/src/cursive.rs
@@ -9,7 +9,7 @@ use std::path::Path;
 use std::sync::mpsc;
 use theme;
 use vec::Vec2;
-use view::{self, Finder, View};
+use view::{self, AnyView, Finder, View};
 use views;
 
 /// Identifies a screen in the cursive root.
@@ -418,7 +418,7 @@ impl Cursive {
     }
 
     /// Convenient method to remove a layer from the current screen.
-    pub fn pop_layer(&mut self) -> Option<Box<View>> {
+    pub fn pop_layer(&mut self) -> Option<Box<AnyView>> {
         let result = self.screen_mut().pop_layer();
         self.clear();
         result
diff --git a/src/view/mod.rs b/src/view/mod.rs
index ca21b01..91fd629 100644
--- a/src/view/mod.rs
+++ b/src/view/mod.rs
@@ -35,15 +35,6 @@
 //!   no matter what the request is. This means calling `View::layout()` with
 //!   a size returned by `required_size` is **never** an error.
 
-/// Helper macro to implement `View::as_any` and `View::as_any_mut`
-#[macro_export]
-macro_rules! view_any {
-    () => {
-        fn as_any(&self) -> &::std::any::Any { self }
-        fn as_any_mut(&mut self) -> &mut ::std::any::Any { self }
-    }
-}
-
 #[macro_use]
 mod view_wrapper;
 
@@ -73,6 +64,23 @@ use std::any::Any;
 use vec::Vec2;
 use views::IdView;
 
+/// A view that can be downcasted to its concrete type.
+pub trait AnyView: View {
+    /// Downcast self to a `Any`.
+    fn as_any(&self) -> &Any;
+
+    /// Downcast self to a mutable `Any`.
+    fn as_any_mut(&mut self) -> &mut Any;
+}
+
+impl <T: View> AnyView for T {
+    /// Downcast self to a `Any`.
+    fn as_any(&self) -> &Any { self }
+
+    /// Downcast self to a mutable `Any`.
+    fn as_any_mut(&mut self) -> &mut Any { self }
+}
+
 /// Main trait defining a view behaviour.
 pub trait View: Any {
     /// Called when a key was pressed.
@@ -82,11 +90,6 @@ pub trait View: Any {
         EventResult::Ignored
     }
 
-    /// Downcast self to a `Any`.
-    fn as_any(&self) -> &Any;
-
-    /// Downcast self to a mutable `Any`.
-    fn as_any_mut(&mut self) -> &mut Any;
 
     /// Returns the minimum size the view requires with the given restrictions.
     ///
diff --git a/src/view/view_wrapper.rs b/src/view/view_wrapper.rs
index 208649e..d0552b2 100644
--- a/src/view/view_wrapper.rs
+++ b/src/view/view_wrapper.rs
@@ -78,7 +78,9 @@ pub trait ViewWrapper: 'static {
 
     /// Wraps the `find` method.
     fn wrap_call_on_any<'a>(
-        &mut self, selector: &Selector, callback: Box<FnMut(&mut Any) + 'a>
+        &mut self,
+        selector: &Selector,
+        callback: Box<FnMut(&mut Any) + 'a>,
     ) {
         self.with_view_mut(|v| v.call_on_any(selector, callback));
     }
@@ -98,8 +100,12 @@ pub trait ViewWrapper: 'static {
 // Some types easily implement ViewWrapper.
 // This includes Box<T: View>
 use std::ops::{Deref, DerefMut};
-impl<U: View + ?Sized, T: Deref<Target = U> + DerefMut + 'static> ViewWrapper
-    for T {
+
+impl<U, T> ViewWrapper for T
+where
+    U: View + ?Sized,
+    T: Deref<Target = U> + DerefMut + 'static,
+{
     type V = U;
 
     fn with_view<F, R>(&self, f: F) -> Option<R>
@@ -119,8 +125,6 @@ impl<U: View + ?Sized, T: Deref<Target = U> + DerefMut + 'static> ViewWrapper
 
 // The main point of implementing ViewWrapper is to have View for free.
 impl<T: ViewWrapper> View for T {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         self.wrap_draw(printer);
     }
@@ -142,7 +146,9 @@ impl<T: ViewWrapper> View for 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>,
     ) {
         self.wrap_call_on_any(selector, callback)
     }
diff --git a/src/views/button.rs b/src/views/button.rs
index 9f5ab11..a0ec0fc 100644
--- a/src/views/button.rs
+++ b/src/views/button.rs
@@ -126,8 +126,6 @@ impl Button {
 }
 
 impl View for Button {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         if printer.size.x == 0 {
             return;
diff --git a/src/views/canvas.rs b/src/views/canvas.rs
index 5766079..8d5d7af 100644
--- a/src/views/canvas.rs
+++ b/src/views/canvas.rs
@@ -173,8 +173,6 @@ impl<T> Canvas<T> {
 }
 
 impl<T: 'static> View for Canvas<T> {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         (self.draw)(&self.state, printer);
     }
diff --git a/src/views/checkbox.rs b/src/views/checkbox.rs
index 3fd5ea8..6f8aef4 100644
--- a/src/views/checkbox.rs
+++ b/src/views/checkbox.rs
@@ -105,8 +105,6 @@ impl Checkbox {
 }
 
 impl View for Checkbox {
-    view_any!();
-
     fn required_size(&mut self, _: Vec2) -> Vec2 {
         Vec2::new(3, 1)
     }
diff --git a/src/views/dialog.rs b/src/views/dialog.rs
index 17cabc8..c76f277 100644
--- a/src/views/dialog.rs
+++ b/src/views/dialog.rs
@@ -10,7 +10,7 @@ use std::cmp::max;
 use theme::ColorStyle;
 use unicode_width::UnicodeWidthStr;
 use vec::{Vec2, Vec4};
-use view::{Selector, View};
+use view::{AnyView, Selector, View};
 use views::{Button, DummyView, SizedView, TextView};
 
 #[derive(PartialEq)]
@@ -53,7 +53,7 @@ pub struct Dialog {
     title_position: HAlign,
 
     // The actual inner view.
-    content: SizedView<Box<View>>,
+    content: SizedView<Box<AnyView>>,
 
     // Optional list of buttons under the main view.
     // Include the top-left corner.
@@ -423,8 +423,6 @@ impl Dialog {
 }
 
 impl View for Dialog {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         // This will be the buttons_height used by the buttons.
         let buttons_height = match self.draw_buttons(printer) {
diff --git a/src/views/dummy.rs b/src/views/dummy.rs
index 2123a50..5b88176 100644
--- a/src/views/dummy.rs
+++ b/src/views/dummy.rs
@@ -7,7 +7,5 @@ use view::View;
 pub struct DummyView;
 
 impl View for DummyView {
-    view_any!();
-
     fn draw(&self, _: &Printer) {}
 }
diff --git a/src/views/edit_view.rs b/src/views/edit_view.rs
index 4faee7c..4a2b775 100644
--- a/src/views/edit_view.rs
+++ b/src/views/edit_view.rs
@@ -434,8 +434,6 @@ fn make_small_stars(length: usize) -> &'static str {
 }
 
 impl View for EditView {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         assert_eq!(
             printer.size.x,
diff --git a/src/views/linear_layout.rs b/src/views/linear_layout.rs
index f88606c..e191a8a 100644
--- a/src/views/linear_layout.rs
+++ b/src/views/linear_layout.rs
@@ -7,8 +7,7 @@ use std::any::Any;
 use std::cmp::min;
 use std::ops::Deref;
 use vec::Vec2;
-use view::{Selector, SizeCache};
-use view::View;
+use view::{AnyView, View, Selector, SizeCache};
 
 /// Arranges its children linearly according to its orientation.
 pub struct LinearLayout {
@@ -20,7 +19,7 @@ pub struct LinearLayout {
 }
 
 struct Child {
-    view: Box<View>,
+    view: Box<AnyView>,
     // The last result from the child's required_size
     // Doesn't have to be what the child actually gets.
     size: Vec2,
@@ -34,7 +33,7 @@ impl Child {
         self.size
     }
 
-    fn as_view(&self) -> &View {
+    fn as_view(&self) -> &AnyView {
         &*self.view
     }
 }
@@ -161,12 +160,12 @@ impl LinearLayout {
     }
 
     /// Returns a reference to a child.
-    pub fn get_child(&self, i: usize) -> Option<&View> {
+    pub fn get_child(&self, i: usize) -> Option<&AnyView> {
         self.children.get(i).map(|child| &*child.view)
     }
 
     /// Returns a mutable reference to a child.
-    pub fn get_child_mut(&mut self, i: usize) -> Option<&mut View> {
+    pub fn get_child_mut(&mut self, i: usize) -> Option<&mut AnyView> {
         self.children.get_mut(i).map(|child| &mut *child.view)
     }
 
@@ -297,8 +296,6 @@ fn try_focus(
 }
 
 impl View for LinearLayout {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         // Use pre-computed sizes
         // eprintln!("Pre loop!");
diff --git a/src/views/list_view.rs b/src/views/list_view.rs
index e419cd2..4925d99 100644
--- a/src/views/list_view.rs
+++ b/src/views/list_view.rs
@@ -7,16 +7,14 @@ use std::any::Any;
 use std::rc::Rc;
 use unicode_width::UnicodeWidthStr;
 use vec::Vec2;
-use view::ScrollBase;
-use view::Selector;
-use view::View;
+use view::{AnyView, ScrollBase, Selector, View};
 
 /// Represents a child from a [`ListView`].
 ///
 /// [`ListView`]: struct.ListView.html
 pub enum ListChild {
     /// A single row, with a label and a view.
-    Row(String, Box<View>),
+    Row(String, Box<AnyView>),
     /// A delimiter between groups.
     Delimiter,
 }
@@ -29,7 +27,7 @@ impl ListChild {
         }
     }
 
-    fn view(&mut self) -> Option<&mut View> {
+    fn view(&mut self) -> Option<&mut AnyView> {
         match *self {
             ListChild::Row(_, ref mut view) => Some(view.as_mut()),
             _ => None,
@@ -150,7 +148,9 @@ impl ListView {
     }
 
     fn iter_mut<'a>(
-        &'a mut self, from_focus: bool, source: direction::Relative
+        &'a mut self,
+        from_focus: bool,
+        source: direction::Relative,
     ) -> Box<Iterator<Item = (usize, &mut ListChild)> + 'a> {
         match source {
             direction::Relative::Front => {
@@ -174,7 +174,9 @@ impl ListView {
     }
 
     fn move_focus(
-        &mut self, n: usize, source: direction::Direction
+        &mut self,
+        n: usize,
+        source: direction::Direction,
     ) -> EventResult {
         let i = if let Some(i) = source
             .relative(direction::Orientation::Vertical)
@@ -248,7 +250,8 @@ impl ListView {
 }
 
 fn try_focus(
-    (i, child): (usize, &mut ListChild), source: direction::Direction
+    (i, child): (usize, &mut ListChild),
+    source: direction::Direction,
 ) -> Option<usize> {
     match *child {
         ListChild::Delimiter => None,
@@ -261,9 +264,6 @@ fn try_focus(
 }
 
 impl View for ListView {
-    view_any!();
-
-
     fn draw(&self, printer: &Printer) {
         if self.children.is_empty() {
             return;
@@ -454,7 +454,8 @@ impl View for ListView {
     }
 
     fn call_on_any<'a>(
-        &mut self, selector: &Selector,
+        &mut self,
+        selector: &Selector,
         mut callback: Box<FnMut(&mut Any) + 'a>,
     ) {
         for view in self.children.iter_mut().filter_map(ListChild::view) {
diff --git a/src/views/menu_popup.rs b/src/views/menu_popup.rs
index 7da673e..365ec13 100644
--- a/src/views/menu_popup.rs
+++ b/src/views/menu_popup.rs
@@ -199,8 +199,6 @@ impl MenuPopup {
 }
 
 impl View for MenuPopup {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         if !printer.size.fits((2, 2)) {
             return;
diff --git a/src/views/menubar.rs b/src/views/menubar.rs
index b39dee3..abb83fc 100644
--- a/src/views/menubar.rs
+++ b/src/views/menubar.rs
@@ -259,8 +259,6 @@ fn show_child(s: &mut Cursive, offset: Vec2, menu: Rc<MenuTree>) {
 }
 
 impl View for Menubar {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         // Draw the bar at the top
         printer.with_color(ColorStyle::primary(), |printer| {
diff --git a/src/views/progress_bar.rs b/src/views/progress_bar.rs
index b0f2bdb..44538e4 100644
--- a/src/views/progress_bar.rs
+++ b/src/views/progress_bar.rs
@@ -193,8 +193,6 @@ impl ProgressBar {
 }
 
 impl View for ProgressBar {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         // Now, the bar itself...
         let available = printer.size.x;
diff --git a/src/views/radio.rs b/src/views/radio.rs
index 0f5a247..15cd4e3 100644
--- a/src/views/radio.rs
+++ b/src/views/radio.rs
@@ -154,9 +154,6 @@ impl<T> RadioButton<T> {
 }
 
 impl<T: 'static> View for RadioButton<T> {
-    view_any!();
-
-
     fn required_size(&mut self, _: Vec2) -> Vec2 {
         self.req_size()
     }
diff --git a/src/views/select_view.rs b/src/views/select_view.rs
index be529f6..dfd2897 100644
--- a/src/views/select_view.rs
+++ b/src/views/select_view.rs
@@ -570,8 +570,6 @@ impl SelectView<String> {
 }
 
 impl<T: 'static> View for SelectView<T> {
-    view_any!();
-
 
     fn draw(&self, printer: &Printer) {
         self.last_offset.set(printer.offset);
diff --git a/src/views/slider_view.rs b/src/views/slider_view.rs
index 13f7fce..01476ef 100644
--- a/src/views/slider_view.rs
+++ b/src/views/slider_view.rs
@@ -112,8 +112,6 @@ impl SliderView {
 }
 
 impl View for SliderView {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         match self.orientation {
             Orientation::Vertical => {
diff --git a/src/views/stack_view.rs b/src/views/stack_view.rs
index 63177dc..794c7bb 100644
--- a/src/views/stack_view.rs
+++ b/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, ViewWrapper};
+use view::{AnyView, Offset, Position, Selector, View, ViewWrapper};
 use views::{Layer, ShadowView};
 
 /// Simple stack of views.
@@ -71,8 +71,6 @@ impl<T: View> ChildWrapper<T> {
 
 // TODO: use macros to make this less ugly?
 impl<T: View> View for ChildWrapper<T> {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         match *self {
             ChildWrapper::Shadow(ref v) => v.draw(printer),
@@ -130,7 +128,7 @@ impl<T: View> View for ChildWrapper<T> {
 }
 
 struct Child {
-    view: ChildWrapper<Box<View>>,
+    view: ChildWrapper<Box<AnyView>>,
     size: Vec2,
     placement: Placement,
 
@@ -159,7 +157,7 @@ impl StackView {
     where
         T: 'static + View,
     {
-        let boxed: Box<View> = Box::new(view);
+        let boxed: Box<AnyView> = Box::new(view);
         self.layers.push(Child {
             view: ChildWrapper::Plain(Layer::new(boxed)),
             size: Vec2::zero(),
@@ -201,7 +199,7 @@ impl StackView {
     where
         T: 'static + View,
     {
-        let boxed: Box<View> = Box::new(view);
+        let boxed: Box<AnyView> = Box::new(view);
         self.layers.push(Child {
             // Skip padding for absolute/parent-placed views
             view: ChildWrapper::Shadow(
@@ -226,7 +224,7 @@ impl StackView {
     }
 
     /// Remove the top-most layer.
-    pub fn pop_layer(&mut self) -> Option<Box<View>> {
+    pub fn pop_layer(&mut self) -> Option<Box<AnyView>> {
         self.layers.pop().map(|child| child.view.unwrap())
     }
 
@@ -324,8 +322,6 @@ impl<R: Deref<Target = Child>, I: Iterator<Item = R>> Iterator
 }
 
 impl View for StackView {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         let last = self.layers.len();
         printer.with_color(ColorStyle::primary(), |printer| {
diff --git a/src/views/text_area.rs b/src/views/text_area.rs
index ea0a12c..3e72e43 100644
--- a/src/views/text_area.rs
+++ b/src/views/text_area.rs
@@ -396,8 +396,6 @@ impl TextArea {
 }
 
 impl View for TextArea {
-    view_any!();
-
     fn required_size(&mut self, constraint: Vec2) -> Vec2 {
         // Make sure our structure is up to date
         self.soft_compute_rows(constraint);
diff --git a/src/views/text_view.rs b/src/views/text_view.rs
index d175f3f..72c9c75 100644
--- a/src/views/text_view.rs
+++ b/src/views/text_view.rs
@@ -448,8 +448,6 @@ impl TextView {
 }
 
 impl View for TextView {
-    view_any!();
-
     fn draw(&self, printer: &Printer) {
         let h = self.rows.len();
         // If the content is smaller than the view, align it somewhere.