Merge pull request #1644 from nicksenger/fix/lazy-widget

Fix `overlay` implementation for `Lazy` widget

4 files changed, 212 insertions, 219 deletions

diff --git a/examples/cached/Cargo.toml b/examples/cached/Cargo.toml
deleted file mode 100644
index 2c7edde2..00000000
--- a/examples/cached/Cargo.toml
+++ /dev/null
@@ -1,10 +0,0 @@
-[package]
-name = "cached"
-version = "0.1.0"
-authors = ["Nick Senger <dev@nsenger.com>"]
-edition = "2021"
-publish = false
-
-[dependencies]
-iced = { path = "../..", features = ["debug"] }
-iced_lazy = { path = "../../lazy" }
diff --git a/examples/cached/src/main.rs b/examples/cached/src/main.rs
deleted file mode 100644
index 8845b874..00000000
--- a/examples/cached/src/main.rs
+++ /dev/null
@@ -1,139 +0,0 @@
-use iced::theme;
-use iced::widget::{
-    button, column, horizontal_space, row, scrollable, text, text_input,
-};
-use iced::{Element, Length, Sandbox, Settings};
-use iced_lazy::lazy;
-
-use std::collections::HashSet;
-
-pub fn main() -> iced::Result {
-    App::run(Settings::default())
-}
-
-struct App {
-    options: HashSet<String>,
-    input: String,
-    order: Order,
-}
-
-impl Default for App {
-    fn default() -> Self {
-        Self {
-            options: ["Foo", "Bar", "Baz", "Qux", "Corge", "Waldo", "Fred"]
-                .into_iter()
-                .map(ToString::to_string)
-                .collect(),
-            input: Default::default(),
-            order: Order::Ascending,
-        }
-    }
-}
-
-#[derive(Debug, Clone)]
-enum Message {
-    InputChanged(String),
-    ToggleOrder,
-    DeleteOption(String),
-    AddOption(String),
-}
-
-impl Sandbox for App {
-    type Message = Message;
-
-    fn new() -> Self {
-        Self::default()
-    }
-
-    fn title(&self) -> String {
-        String::from("Cached - Iced")
-    }
-
-    fn update(&mut self, message: Message) {
-        match message {
-            Message::InputChanged(input) => {
-                self.input = input;
-            }
-            Message::ToggleOrder => {
-                self.order = match self.order {
-                    Order::Ascending => Order::Descending,
-                    Order::Descending => Order::Ascending,
-                }
-            }
-            Message::AddOption(option) => {
-                self.options.insert(option);
-                self.input.clear();
-            }
-            Message::DeleteOption(option) => {
-                self.options.remove(&option);
-            }
-        }
-    }
-
-    fn view(&self) -> Element<Message> {
-        let options = lazy((&self.order, self.options.len()), || {
-            let mut options: Vec<_> = self.options.iter().collect();
-
-            options.sort_by(|a, b| match self.order {
-                Order::Ascending => a.to_lowercase().cmp(&b.to_lowercase()),
-                Order::Descending => b.to_lowercase().cmp(&a.to_lowercase()),
-            });
-
-            column(
-                options
-                    .into_iter()
-                    .map(|option| {
-                        row![
-                            text(option),
-                            horizontal_space(Length::Fill),
-                            button("Delete")
-                                .on_press(Message::DeleteOption(
-                                    option.to_string(),
-                                ),)
-                                .style(theme::Button::Destructive)
-                        ]
-                        .into()
-                    })
-                    .collect(),
-            )
-            .spacing(10)
-        });
-
-        column![
-            scrollable(options).height(Length::Fill),
-            row![
-                text_input(
-                    "Add a new option",
-                    &self.input,
-                    Message::InputChanged,
-                )
-                .on_submit(Message::AddOption(self.input.clone())),
-                button(text(format!("Toggle Order ({})", self.order)))
-                    .on_press(Message::ToggleOrder)
-            ]
-            .spacing(10)
-        ]
-        .spacing(20)
-        .padding(20)
-        .into()
-    }
-}
-
-#[derive(Debug, Hash)]
-enum Order {
-    Ascending,
-    Descending,
-}
-
-impl std::fmt::Display for Order {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(
-            f,
-            "{}",
-            match self {
-                Self::Ascending => "Ascending",
-                Self::Descending => "Descending",
-            }
-        )
-    }
-}
diff --git a/examples/lazy/src/main.rs b/examples/lazy/src/main.rs
index 8845b874..818c91bc 100644
--- a/examples/lazy/src/main.rs
+++ b/examples/lazy/src/main.rs
@@ -1,18 +1,21 @@
 use iced::theme;
 use iced::widget::{
-    button, column, horizontal_space, row, scrollable, text, text_input,
+    button, column, horizontal_space, pick_list, row, scrollable, text,
+    text_input,
 };
 use iced::{Element, Length, Sandbox, Settings};
 use iced_lazy::lazy;
 
 use std::collections::HashSet;
+use std::hash::Hash;
 
 pub fn main() -> iced::Result {
     App::run(Settings::default())
 }
 
 struct App {
-    options: HashSet<String>,
+    version: u8,
+    items: HashSet<Item>,
     input: String,
     order: Order,
 }
@@ -20,9 +23,10 @@ struct App {
 impl Default for App {
     fn default() -> Self {
         Self {
-            options: ["Foo", "Bar", "Baz", "Qux", "Corge", "Waldo", "Fred"]
+            version: 0,
+            items: ["Foo", "Bar", "Baz", "Qux", "Corge", "Waldo", "Fred"]
                 .into_iter()
-                .map(ToString::to_string)
+                .map(From::from)
                 .collect(),
             input: Default::default(),
             order: Order::Ascending,
@@ -30,12 +34,92 @@ impl Default for App {
     }
 }
 
+#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
+enum Color {
+    #[default]
+    Black,
+    Red,
+    Orange,
+    Yellow,
+    Green,
+    Blue,
+    Purple,
+}
+
+impl Color {
+    const ALL: &[Color] = &[
+        Color::Black,
+        Color::Red,
+        Color::Orange,
+        Color::Yellow,
+        Color::Green,
+        Color::Blue,
+        Color::Purple,
+    ];
+}
+
+impl std::fmt::Display for Color {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::Black => "Black",
+            Self::Red => "Red",
+            Self::Orange => "Orange",
+            Self::Yellow => "Yellow",
+            Self::Green => "Green",
+            Self::Blue => "Blue",
+            Self::Purple => "Purple",
+        })
+    }
+}
+
+impl From<Color> for iced::Color {
+    fn from(value: Color) -> Self {
+        match value {
+            Color::Black => iced::Color::from_rgb8(0, 0, 0),
+            Color::Red => iced::Color::from_rgb8(220, 50, 47),
+            Color::Orange => iced::Color::from_rgb8(203, 75, 22),
+            Color::Yellow => iced::Color::from_rgb8(181, 137, 0),
+            Color::Green => iced::Color::from_rgb8(133, 153, 0),
+            Color::Blue => iced::Color::from_rgb8(38, 139, 210),
+            Color::Purple => iced::Color::from_rgb8(108, 113, 196),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Eq)]
+struct Item {
+    name: String,
+    color: Color,
+}
+
+impl Hash for Item {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.name.hash(state);
+    }
+}
+
+impl PartialEq for Item {
+    fn eq(&self, other: &Self) -> bool {
+        self.name.eq(&other.name)
+    }
+}
+
+impl From<&str> for Item {
+    fn from(s: &str) -> Self {
+        Self {
+            name: s.to_owned(),
+            color: Default::default(),
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 enum Message {
     InputChanged(String),
     ToggleOrder,
-    DeleteOption(String),
-    AddOption(String),
+    DeleteItem(Item),
+    AddItem(String),
+    ItemColorChanged(Item, Color),
 }
 
 impl Sandbox for App {
@@ -46,7 +130,7 @@ impl Sandbox for App {
     }
 
     fn title(&self) -> String {
-        String::from("Cached - Iced")
+        String::from("Lazy - Iced")
     }
 
     fn update(&mut self, message: Message) {
@@ -55,43 +139,71 @@ impl Sandbox for App {
                 self.input = input;
             }
             Message::ToggleOrder => {
+                self.version = self.version.wrapping_add(1);
                 self.order = match self.order {
                     Order::Ascending => Order::Descending,
                     Order::Descending => Order::Ascending,
                 }
             }
-            Message::AddOption(option) => {
-                self.options.insert(option);
+            Message::AddItem(name) => {
+                self.version = self.version.wrapping_add(1);
+                self.items.insert(name.as_str().into());
                 self.input.clear();
             }
-            Message::DeleteOption(option) => {
-                self.options.remove(&option);
+            Message::DeleteItem(item) => {
+                self.version = self.version.wrapping_add(1);
+                self.items.remove(&item);
+            }
+            Message::ItemColorChanged(item, color) => {
+                self.version = self.version.wrapping_add(1);
+                if self.items.remove(&item) {
+                    self.items.insert(Item {
+                        name: item.name,
+                        color,
+                    });
+                }
             }
         }
     }
 
     fn view(&self) -> Element<Message> {
-        let options = lazy((&self.order, self.options.len()), || {
-            let mut options: Vec<_> = self.options.iter().collect();
+        let options = lazy(self.version, || {
+            let mut items: Vec<_> = self.items.iter().cloned().collect();
 
-            options.sort_by(|a, b| match self.order {
-                Order::Ascending => a.to_lowercase().cmp(&b.to_lowercase()),
-                Order::Descending => b.to_lowercase().cmp(&a.to_lowercase()),
+            items.sort_by(|a, b| match self.order {
+                Order::Ascending => {
+                    a.name.to_lowercase().cmp(&b.name.to_lowercase())
+                }
+                Order::Descending => {
+                    b.name.to_lowercase().cmp(&a.name.to_lowercase())
+                }
             });
 
             column(
-                options
+                items
                     .into_iter()
-                    .map(|option| {
+                    .map(|item| {
+                        let button = button("Delete")
+                            .on_press(Message::DeleteItem(item.clone()))
+                            .style(theme::Button::Destructive);
+
                         row![
-                            text(option),
+                            text(&item.name)
+                                .style(theme::Text::Color(item.color.into())),
                             horizontal_space(Length::Fill),
-                            button("Delete")
-                                .on_press(Message::DeleteOption(
-                                    option.to_string(),
-                                ),)
-                                .style(theme::Button::Destructive)
+                            pick_list(
+                                Color::ALL,
+                                Some(item.color),
+                                move |color| {
+                                    Message::ItemColorChanged(
+                                        item.clone(),
+                                        color,
+                                    )
+                                }
+                            ),
+                            button
                         ]
+                        .spacing(20)
                         .into()
                     })
                     .collect(),
@@ -107,7 +219,7 @@ impl Sandbox for App {
                     &self.input,
                     Message::InputChanged,
                 )
-                .on_submit(Message::AddOption(self.input.clone())),
+                .on_submit(Message::AddItem(self.input.clone())),
                 button(text(format!("Toggle Order ({})", self.order)))
                     .on_press(Message::ToggleOrder)
             ]
diff --git a/lazy/src/lazy.rs b/lazy/src/lazy.rs
index ec35e8f0..16709f8d 100644
--- a/lazy/src/lazy.rs
+++ b/lazy/src/lazy.rs
@@ -9,16 +9,17 @@ use iced_native::Element;
 use iced_native::{Clipboard, Hasher, Length, Point, Rectangle, Shell, Size};
 
 use ouroboros::self_referencing;
-use std::cell::{Ref, RefCell, RefMut};
+use std::cell::RefCell;
 use std::hash::{Hash, Hasher as H};
-use std::marker::PhantomData;
 use std::rc::Rc;
 
 #[allow(missing_debug_implementations)]
 pub struct Lazy<'a, Message, Renderer, Dependency, View> {
     dependency: Dependency,
     view: Box<dyn Fn() -> View + 'a>,
-    element: RefCell<Option<Rc<RefCell<Element<'static, Message, Renderer>>>>>,
+    element: RefCell<
+        Option<Rc<RefCell<Option<Element<'static, Message, Renderer>>>>>,
+    >,
 }
 
 impl<'a, Message, Renderer, Dependency, View>
@@ -37,21 +38,35 @@ where
 
     fn with_element<T>(
         &self,
-        f: impl FnOnce(Ref<Element<Message, Renderer>>) -> T,
+        f: impl FnOnce(&Element<Message, Renderer>) -> T,
     ) -> T {
-        f(self.element.borrow().as_ref().unwrap().borrow())
+        f(self
+            .element
+            .borrow()
+            .as_ref()
+            .unwrap()
+            .borrow()
+            .as_ref()
+            .unwrap())
     }
 
     fn with_element_mut<T>(
         &self,
-        f: impl FnOnce(RefMut<Element<Message, Renderer>>) -> T,
+        f: impl FnOnce(&mut Element<Message, Renderer>) -> T,
     ) -> T {
-        f(self.element.borrow().as_ref().unwrap().borrow_mut())
+        f(self
+            .element
+            .borrow()
+            .as_ref()
+            .unwrap()
+            .borrow_mut()
+            .as_mut()
+            .unwrap())
     }
 }
 
 struct Internal<Message, Renderer> {
-    element: Rc<RefCell<Element<'static, Message, Renderer>>>,
+    element: Rc<RefCell<Option<Element<'static, Message, Renderer>>>>,
     hash: u64,
 }
 
@@ -73,7 +88,7 @@ where
         self.dependency.hash(&mut hasher);
         let hash = hasher.finish();
 
-        let element = Rc::new(RefCell::new((self.view)().into()));
+        let element = Rc::new(RefCell::new(Some((self.view)().into())));
 
         (*self.element.borrow_mut()) = Some(element.clone());
 
@@ -81,9 +96,7 @@ where
     }
 
     fn children(&self) -> Vec<Tree> {
-        vec![Tree::new(
-            self.element.borrow().as_ref().unwrap().borrow().as_widget(),
-        )]
+        self.with_element(|element| vec![Tree::new(element.as_widget())])
     }
 
     fn diff(&self, tree: &mut Tree) {
@@ -97,12 +110,12 @@ where
             current.hash = new_hash;
 
             let element = (self.view)().into();
-            current.element = Rc::new(RefCell::new(element));
+            current.element = Rc::new(RefCell::new(Some(element)));
 
             (*self.element.borrow_mut()) = Some(current.element.clone());
-            tree.diff_children(std::slice::from_ref(
-                &self.element.borrow().as_ref().unwrap().borrow().as_widget(),
-            ));
+            self.with_element(|element| {
+                tree.diff_children(std::slice::from_ref(&element.as_widget()))
+            });
         } else {
             (*self.element.borrow_mut()) = Some(current.element.clone());
         }
@@ -153,7 +166,7 @@ where
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
     ) -> event::Status {
-        self.with_element_mut(|mut element| {
+        self.with_element_mut(|element| {
             element.as_widget_mut().on_event(
                 &mut tree.children[0],
                 event,
@@ -214,23 +227,27 @@ where
         layout: Layout<'_>,
         renderer: &Renderer,
     ) -> Option<overlay::Element<'_, Message, Renderer>> {
-        let overlay = OverlayBuilder {
-            cached: self,
-            tree: &mut tree.children[0],
-            types: PhantomData,
-            overlay_builder: |cached, tree| {
-                Rc::get_mut(cached.element.get_mut().as_mut().unwrap())
+        let overlay = Overlay(Some(
+            InnerBuilder {
+                cell: self.element.borrow().as_ref().unwrap().clone(),
+                element: self
+                    .element
+                    .borrow()
+                    .as_ref()
                     .unwrap()
-                    .get_mut()
-                    .as_widget_mut()
-                    .overlay(tree, layout, renderer)
-            },
-        }
-        .build();
-
-        let has_overlay = overlay.with_overlay(|overlay| {
-            overlay.as_ref().map(overlay::Element::position)
-        });
+                    .borrow_mut()
+                    .take()
+                    .unwrap(),
+                tree: &mut tree.children[0],
+                overlay_builder: |element, tree| {
+                    element.as_widget_mut().overlay(tree, layout, renderer)
+                },
+            }
+            .build(),
+        ));
+
+        let has_overlay = overlay
+            .with_overlay_maybe(|overlay| overlay::Element::position(overlay));
 
         has_overlay
             .map(|position| overlay::Element::new(position, Box::new(overlay)))
@@ -238,37 +255,50 @@ where
 }
 
 #[self_referencing]
-struct Overlay<'a, 'b, Message, Renderer, Dependency, View> {
-    cached: &'a mut Lazy<'b, Message, Renderer, Dependency, View>,
+struct Inner<'a, Message, Renderer>
+where
+    Message: 'a,
+    Renderer: 'a,
+{
+    cell: Rc<RefCell<Option<Element<'static, Message, Renderer>>>>,
+    element: Element<'static, Message, Renderer>,
     tree: &'a mut Tree,
-    types: PhantomData<(Message, Dependency, View)>,
 
-    #[borrows(mut cached, mut tree)]
+    #[borrows(mut element, mut tree)]
     #[covariant]
     overlay: Option<overlay::Element<'this, Message, Renderer>>,
 }
 
-impl<'a, 'b, Message, Renderer, Dependency, View>
-    Overlay<'a, 'b, Message, Renderer, Dependency, View>
-{
+struct Overlay<'a, Message, Renderer>(Option<Inner<'a, Message, Renderer>>);
+
+impl<'a, Message, Renderer> Drop for Overlay<'a, Message, Renderer> {
+    fn drop(&mut self) {
+        let heads = self.0.take().unwrap().into_heads();
+        (*heads.cell.borrow_mut()) = Some(heads.element);
+    }
+}
+
+impl<'a, Message, Renderer> Overlay<'a, Message, Renderer> {
     fn with_overlay_maybe<T>(
         &self,
         f: impl FnOnce(&overlay::Element<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.borrow_overlay().as_ref().map(f)
+        self.0.as_ref().unwrap().borrow_overlay().as_ref().map(f)
     }
 
     fn with_overlay_mut_maybe<T>(
         &mut self,
         f: impl FnOnce(&mut overlay::Element<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.with_overlay_mut(|overlay| overlay.as_mut().map(f))
+        self.0
+            .as_mut()
+            .unwrap()
+            .with_overlay_mut(|overlay| overlay.as_mut().map(f))
     }
 }
 
-impl<'a, 'b, Message, Renderer, Dependency, View>
-    overlay::Overlay<Message, Renderer>
-    for Overlay<'a, 'b, Message, Renderer, Dependency, View>
+impl<'a, Message, Renderer> overlay::Overlay<Message, Renderer>
+    for Overlay<'a, Message, Renderer>
 where
     Renderer: iced_native::Renderer,
 {