merged previous stuffs on master

crates/ui/src/menu/dropdown_menu.rs

@@ -0,0 +1,142 @@
+use std::rc::Rc;
+
+use gpui::{
+    Context, Corner, DismissEvent, ElementId, Entity, Focusable, InteractiveElement, IntoElement,
+    RenderOnce, SharedString, StyleRefinement, Styled, Window,
+};
+
+use crate::button::Button;
+use crate::menu::PopupMenu;
+use crate::popover::Popover;
+use crate::Selectable;
+
+/// A dropdown menu trait for buttons and other interactive elements
+pub trait DropdownMenu: Styled + Selectable + InteractiveElement + IntoElement + 'static {
+    /// Create a dropdown menu with the given items, anchored to the TopLeft corner
+    fn dropdown_menu(
+        self,
+        f: impl Fn(PopupMenu, &mut Window, &mut Context<PopupMenu>) -> PopupMenu + 'static,
+    ) -> DropdownMenuPopover<Self> {
+        self.dropdown_menu_with_anchor(Corner::TopLeft, f)
+    }
+
+    /// Create a dropdown menu with the given items, anchored to the given corner
+    fn dropdown_menu_with_anchor(
+        mut self,
+        anchor: impl Into<Corner>,
+        f: impl Fn(PopupMenu, &mut Window, &mut Context<PopupMenu>) -> PopupMenu + 'static,
+    ) -> DropdownMenuPopover<Self> {
+        let style = self.style().clone();
+        let id = self.interactivity().element_id.clone();
+
+        DropdownMenuPopover::new(id.unwrap_or(0.into()), anchor, self, f).trigger_style(style)
+    }
+}
+
+impl DropdownMenu for Button {}
+
+#[derive(IntoElement)]
+pub struct DropdownMenuPopover<T: Selectable + IntoElement + 'static> {
+    id: ElementId,
+    style: StyleRefinement,
+    anchor: Corner,
+    trigger: T,
+    #[allow(clippy::type_complexity)]
+    builder: Rc<dyn Fn(PopupMenu, &mut Window, &mut Context<PopupMenu>) -> PopupMenu>,
+}
+
+impl<T> DropdownMenuPopover<T>
+where
+    T: Selectable + IntoElement + 'static,
+{
+    fn new(
+        id: ElementId,
+        anchor: impl Into<Corner>,
+        trigger: T,
+        builder: impl Fn(PopupMenu, &mut Window, &mut Context<PopupMenu>) -> PopupMenu + 'static,
+    ) -> Self {
+        Self {
+            id: SharedString::from(format!("dropdown-menu:{:?}", id)).into(),
+            style: StyleRefinement::default(),
+            anchor: anchor.into(),
+            trigger,
+            builder: Rc::new(builder),
+        }
+    }
+
+    /// Set the anchor corner for the dropdown menu popover.
+    pub fn anchor(mut self, anchor: impl Into<Corner>) -> Self {
+        self.anchor = anchor.into();
+        self
+    }
+
+    /// Set the style refinement for the dropdown menu trigger.
+    fn trigger_style(mut self, style: StyleRefinement) -> Self {
+        self.style = style;
+        self
+    }
+}
+
+#[derive(Default)]
+struct DropdownMenuState {
+    menu: Option<Entity<PopupMenu>>,
+}
+
+impl<T> RenderOnce for DropdownMenuPopover<T>
+where
+    T: Selectable + IntoElement + 'static,
+{
+    fn render(self, window: &mut Window, cx: &mut gpui::App) -> impl IntoElement {
+        let builder = self.builder.clone();
+        let menu_state =
+            window.use_keyed_state(self.id.clone(), cx, |_, _| DropdownMenuState::default());
+
+        Popover::new(SharedString::from(format!("popover:{}", self.id)))
+            .appearance(false)
+            .overlay_closable(false)
+            .trigger(self.trigger)
+            .trigger_style(self.style)
+            .anchor(self.anchor)
+            .content(move |_, window, cx| {
+                // Here is special logic to only create the PopupMenu once and reuse it.
+                // Because this `content` will called in every time render, so we need to store the menu
+                // in state to avoid recreating at every render.
+                //
+                // And we also need to rebuild the menu when it is dismissed, to rebuild menu items
+                // dynamically for support `dropdown_menu` method, so we listen for DismissEvent below.
+                let menu = match menu_state.read(cx).menu.clone() {
+                    Some(menu) => menu,
+                    None => {
+                        let builder = builder.clone();
+                        let menu = PopupMenu::build(window, cx, move |menu, window, cx| {
+                            builder(menu, window, cx)
+                        });
+                        menu_state.update(cx, |state, _| {
+                            state.menu = Some(menu.clone());
+                        });
+                        menu.focus_handle(cx).focus(window, cx);
+
+                        // Listen for dismiss events from the PopupMenu to close the popover.
+                        let popover_state = cx.entity();
+                        window
+                            .subscribe(&menu, cx, {
+                                let menu_state = menu_state.clone();
+                                move |_, _: &DismissEvent, window, cx| {
+                                    popover_state.update(cx, |state, cx| {
+                                        state.dismiss(window, cx);
+                                    });
+                                    menu_state.update(cx, |state, _| {
+                                        state.menu = None;
+                                    });
+                                }
+                            })
+                            .detach();
+
+                        menu.clone()
+                    }
+                };
+
+                menu.clone()
+            })
+    }
+}