From 0fbf84e6bc9cd7ae06ab9b8fcaed44997bfb2144 Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Thu, 19 Oct 2023 22:28:42 +0200
Subject: [PATCH] Checkpoint

---
 crates/gpui3/src/element.rs      | 68 ++++++++++++++++++++++++++------
 crates/gpui3/src/elements/div.rs | 47 +++++++++++-----------
 crates/gpui3/src/elements/img.rs | 34 ++++++++--------
 crates/gpui3/src/elements/svg.rs | 34 ++++++++--------
 4 files changed, 115 insertions(+), 68 deletions(-)

diff --git a/crates/gpui3/src/element.rs b/crates/gpui3/src/element.rs
index 961a22a5f9..7e0e46cb26 100644
--- a/crates/gpui3/src/element.rs
+++ b/crates/gpui3/src/element.rs
@@ -5,7 +5,7 @@ use crate::{
 use derive_more::{Deref, DerefMut};
 use refineable::Refineable;
 pub(crate) use smallvec::SmallVec;
-use std::mem;
+use std::{marker::PhantomData, mem};
 
 pub trait Element: 'static + Send + Sync + IntoAnyElement<Self::ViewState> {
     type ViewState: 'static + Send + Sync;
@@ -39,22 +39,66 @@ pub trait Element: 'static + Send + Sync + IntoAnyElement<Self::ViewState> {
 #[derive(Deref, DerefMut, Default, Clone, Debug, Eq, PartialEq, Hash)]
 pub struct GlobalElementId(SmallVec<[ElementId; 32]>);
 
-pub trait ElementIdentity: 'static + Send + Sync {
-    fn id(&self) -> Option<ElementId>;
-}
+pub trait ElementInteractivity<V: 'static + Send + Sync>: 'static + Send + Sync {
+    fn as_stateful(&self) -> Option<&StatefulInteractivity<V>>;
 
-pub struct Identified(pub(crate) ElementId);
-
-impl ElementIdentity for Identified {
-    fn id(&self) -> Option<ElementId> {
-        Some(self.0.clone())
+    fn initialize<R>(
+        &self,
+        cx: &mut ViewContext<V>,
+        f: impl FnOnce(Option<GlobalElementId>, &mut ViewContext<V>) -> R,
+    ) -> R {
+        if let Some(identified) = self.as_stateful() {
+            cx.with_element_id(identified.id.clone(), |global_id, cx| {
+                f(Some(global_id), cx)
+            })
+        } else {
+            f(None, cx)
+        }
     }
 }
 
-pub struct Anonymous;
+#[derive(Deref, DerefMut)]
+pub struct StatefulInteractivity<V: 'static + Send + Sync> {
+    pub id: ElementId,
+    #[deref]
+    #[deref_mut]
+    common: StatelessInteractivity<V>,
+}
 
-impl ElementIdentity for Anonymous {
-    fn id(&self) -> Option<ElementId> {
+impl<V> ElementInteractivity<V> for StatefulInteractivity<V>
+where
+    V: 'static + Send + Sync,
+{
+    fn as_stateful(&self) -> Option<&StatefulInteractivity<V>> {
+        Some(self)
+    }
+}
+
+impl<V> From<ElementId> for StatefulInteractivity<V>
+where
+    V: 'static + Send + Sync,
+{
+    fn from(id: ElementId) -> Self {
+        Self {
+            id,
+            common: StatelessInteractivity::default(),
+        }
+    }
+}
+
+pub struct StatelessInteractivity<V>(PhantomData<V>);
+
+impl<V> Default for StatelessInteractivity<V> {
+    fn default() -> Self {
+        Self(PhantomData)
+    }
+}
+
+impl<V> ElementInteractivity<V> for StatelessInteractivity<V>
+where
+    V: 'static + Send + Sync,
+{
+    fn as_stateful(&self) -> Option<&StatefulInteractivity<V>> {
         None
     }
 }
diff --git a/crates/gpui3/src/elements/div.rs b/crates/gpui3/src/elements/div.rs
index 33dbe15671..5621ece1c5 100644
--- a/crates/gpui3/src/elements/div.rs
+++ b/crates/gpui3/src/elements/div.rs
@@ -1,9 +1,10 @@
 use crate::{
-    Active, Anonymous, AnyElement, AppContext, BorrowWindow, Bounds, Click, DispatchPhase, Element,
-    ElementFocusability, ElementId, ElementIdentity, Focus, FocusHandle, FocusListeners, Focusable,
-    GlobalElementId, Hover, Identified, Interactive, Interactivity, IntoAnyElement, KeyDownEvent,
+    Active, AnyElement, AppContext, BorrowWindow, Bounds, Click, DispatchPhase, Element,
+    ElementFocusability, ElementId, ElementInteractivity, Focus, FocusHandle, FocusListeners,
+    Focusable, GlobalElementId, Hover, Interactive, Interactivity, IntoAnyElement, KeyDownEvent,
     KeyMatch, LayoutId, MouseDownEvent, MouseMoveEvent, MouseUpEvent, NonFocusable, Overflow,
-    ParentElement, Pixels, Point, SharedString, Style, StyleRefinement, Styled, ViewContext,
+    ParentElement, Pixels, Point, SharedString, StatefulInteractivity, StatelessInteractivity,
+    Style, StyleRefinement, Styled, ViewContext,
 };
 use collections::HashMap;
 use parking_lot::Mutex;
@@ -62,7 +63,7 @@ impl ScrollState {
 
 pub struct Div<
     V: 'static + Send + Sync,
-    I: ElementIdentity = Anonymous,
+    I: ElementInteractivity<V> = StatelessInteractivity<V>,
     F: ElementFocusability<V> = NonFocusable,
 > {
     identity: I,
@@ -77,12 +78,12 @@ pub struct Div<
     group_active: Option<GroupStyle>,
 }
 
-pub fn div<V>() -> Div<V, Anonymous, NonFocusable>
+pub fn div<V>() -> Div<V, StatelessInteractivity<V>, NonFocusable>
 where
     V: 'static + Send + Sync,
 {
     Div {
-        identity: Anonymous,
+        identity: StatelessInteractivity::default(),
         focusability: NonFocusable,
         interactivity: Interactivity::default(),
         children: SmallVec::new(),
@@ -100,14 +101,14 @@ struct GroupStyle {
     style: StyleRefinement,
 }
 
-impl<V, F> Div<V, Anonymous, F>
+impl<V, F> Div<V, StatelessInteractivity<V>, F>
 where
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
-    pub fn id(self, id: impl Into<ElementId>) -> Div<V, Identified, F> {
+    pub fn id(self, id: impl Into<ElementId>) -> Div<V, StatefulInteractivity<V>, F> {
         Div {
-            identity: Identified(id.into()),
+            identity: id.into().into(),
             focusability: self.focusability,
             interactivity: self.interactivity,
             children: self.children,
@@ -123,7 +124,7 @@ where
 
 impl<V, I, F> Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -271,7 +272,7 @@ where
 
 impl<V, I> Div<V, I, NonFocusable>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     V: 'static + Send + Sync,
 {
     pub fn focusable(self, handle: &FocusHandle) -> Div<V, I, Focusable<V>> {
@@ -292,7 +293,7 @@ where
 
 impl<V, I> Focus for Div<V, I, Focusable<V>>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     V: 'static + Send + Sync,
 {
     fn focus_listeners(&mut self) -> &mut FocusListeners<V> {
@@ -318,7 +319,7 @@ where
 
 impl<V, I, F> Element for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -326,7 +327,9 @@ where
     type ElementState = DivState;
 
     fn id(&self) -> Option<ElementId> {
-        self.identity.id()
+        self.identity
+            .as_stateful()
+            .map(|identified| identified.id.clone())
     }
 
     fn initialize(
@@ -456,7 +459,7 @@ where
 
 impl<V, I, F> IntoAnyElement<V> for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -467,7 +470,7 @@ where
 
 impl<V, I, F> ParentElement for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -478,7 +481,7 @@ where
 
 impl<V, I, F> Styled for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -489,7 +492,7 @@ where
 
 impl<V, I, F> Interactive for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -500,7 +503,7 @@ where
 
 impl<V, I, F> Hover for Div<V, I, F>
 where
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
@@ -513,14 +516,14 @@ where
     }
 }
 
-impl<V, F> Click for Div<V, Identified, F>
+impl<V, F> Click for Div<V, StatefulInteractivity<V>, F>
 where
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
 {
 }
 
-impl<V, F> Active for Div<V, Identified, F>
+impl<V, F> Active for Div<V, StatefulInteractivity<V>, F>
 where
     F: ElementFocusability<V>,
     V: 'static + Send + Sync,
diff --git a/crates/gpui3/src/elements/img.rs b/crates/gpui3/src/elements/img.rs
index abc6e1f36a..cf3ceda614 100644
--- a/crates/gpui3/src/elements/img.rs
+++ b/crates/gpui3/src/elements/img.rs
@@ -1,15 +1,15 @@
 use crate::{
-    div, Active, Anonymous, AnyElement, BorrowWindow, Bounds, Click, Div, DivState, Element,
-    ElementFocusability, ElementId, ElementIdentity, Focus, FocusListeners, Focusable, Hover,
-    Identified, Interactive, Interactivity, IntoAnyElement, LayoutId, NonFocusable, Pixels,
-    SharedString, StyleRefinement, Styled, ViewContext,
+    div, Active, AnyElement, BorrowWindow, Bounds, Click, Div, DivState, Element,
+    ElementFocusability, ElementId, ElementInteractivity, Focus, FocusListeners, Focusable, Hover,
+    Interactive, Interactivity, IntoAnyElement, LayoutId, NonFocusable, Pixels, SharedString,
+    StatefulInteractivity, StatelessInteractivity, StyleRefinement, Styled, ViewContext,
 };
 use futures::FutureExt;
 use util::ResultExt;
 
 pub struct Img<
     V: 'static + Send + Sync,
-    I: ElementIdentity = Anonymous,
+    I: ElementInteractivity<V> = StatelessInteractivity<V>,
     F: ElementFocusability<V> = NonFocusable,
 > {
     base: Div<V, I, F>,
@@ -17,7 +17,7 @@ pub struct Img<
     grayscale: bool,
 }
 
-pub fn img<V>() -> Img<V, Anonymous, NonFocusable>
+pub fn img<V>() -> Img<V, StatelessInteractivity<V>, NonFocusable>
 where
     V: 'static + Send + Sync,
 {
@@ -31,7 +31,7 @@ where
 impl<V, I, F> Img<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     pub fn uri(mut self, uri: impl Into<SharedString>) -> Self {
@@ -45,12 +45,12 @@ where
     }
 }
 
-impl<V, F> Img<V, Anonymous, F>
+impl<V, F> Img<V, StatelessInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
 {
-    pub fn id(self, id: impl Into<ElementId>) -> Img<V, Identified, F> {
+    pub fn id(self, id: impl Into<ElementId>) -> Img<V, StatefulInteractivity<V>, F> {
         Img {
             base: self.base.id(id),
             uri: self.uri,
@@ -62,7 +62,7 @@ where
 impl<V, I, F> IntoAnyElement<V> for Img<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn into_any(self) -> AnyElement<V> {
@@ -73,7 +73,7 @@ where
 impl<V, I, F> Element for Img<V, I, F>
 where
     V: Send + Sync + 'static,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     type ViewState = V;
@@ -142,7 +142,7 @@ where
 impl<V, I, F> Styled for Img<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn style(&mut self) -> &mut StyleRefinement {
@@ -153,7 +153,7 @@ where
 impl<V, I, F> Interactive for Img<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn interactivity(&mut self) -> &mut Interactivity<V> {
@@ -164,7 +164,7 @@ where
 impl<V, I, F> Hover for Img<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn set_hover_style(&mut self, group: Option<SharedString>, style: StyleRefinement) {
@@ -172,14 +172,14 @@ where
     }
 }
 
-impl<V, F> Click for Img<V, Identified, F>
+impl<V, F> Click for Img<V, StatefulInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
 {
 }
 
-impl<V, F> Active for Img<V, Identified, F>
+impl<V, F> Active for Img<V, StatefulInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
@@ -192,7 +192,7 @@ where
 impl<V, I> Focus for Img<V, I, Focusable<V>>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
 {
     fn focus_listeners(&mut self) -> &mut FocusListeners<Self::ViewState> {
         self.base.focus_listeners()
diff --git a/crates/gpui3/src/elements/svg.rs b/crates/gpui3/src/elements/svg.rs
index 7ed328a95f..d29e9fbdf3 100644
--- a/crates/gpui3/src/elements/svg.rs
+++ b/crates/gpui3/src/elements/svg.rs
@@ -1,21 +1,21 @@
 use crate::{
-    div, Active, Anonymous, AnyElement, Bounds, Click, Div, DivState, Element, ElementFocusability,
-    ElementId, ElementIdentity, Focus, FocusListeners, Focusable, Hover, Identified, Interactive,
-    Interactivity, IntoAnyElement, LayoutId, NonFocusable, Pixels, SharedString, StyleRefinement,
-    Styled, ViewContext,
+    div, Active, AnyElement, Bounds, Click, Div, DivState, Element, ElementFocusability, ElementId,
+    ElementInteractivity, Focus, FocusListeners, Focusable, Hover, Interactive, Interactivity,
+    IntoAnyElement, LayoutId, NonFocusable, Pixels, SharedString, StatefulInteractivity,
+    StatelessInteractivity, StyleRefinement, Styled, ViewContext,
 };
 use util::ResultExt;
 
 pub struct Svg<
     V: 'static + Send + Sync,
-    I: ElementIdentity = Anonymous,
+    I: ElementInteractivity<V> = StatelessInteractivity<V>,
     F: ElementFocusability<V> = NonFocusable,
 > {
     base: Div<V, I, F>,
     path: Option<SharedString>,
 }
 
-pub fn svg<V>() -> Svg<V, Anonymous, NonFocusable>
+pub fn svg<V>() -> Svg<V, StatelessInteractivity<V>, NonFocusable>
 where
     V: 'static + Send + Sync,
 {
@@ -28,7 +28,7 @@ where
 impl<V, I, F> Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     pub fn path(mut self, path: impl Into<SharedString>) -> Self {
@@ -37,12 +37,12 @@ where
     }
 }
 
-impl<V, F> Svg<V, Anonymous, F>
+impl<V, F> Svg<V, StatelessInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
 {
-    pub fn id(self, id: impl Into<ElementId>) -> Svg<V, Identified, F> {
+    pub fn id(self, id: impl Into<ElementId>) -> Svg<V, StatefulInteractivity<V>, F> {
         Svg {
             base: self.base.id(id),
             path: self.path,
@@ -53,7 +53,7 @@ where
 impl<V, I, F> IntoAnyElement<V> for Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn into_any(self) -> AnyElement<V> {
@@ -64,7 +64,7 @@ where
 impl<V, I, F> Element for Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     type ViewState = V;
@@ -116,7 +116,7 @@ where
 impl<V, I, F> Styled for Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn style(&mut self) -> &mut StyleRefinement {
@@ -127,7 +127,7 @@ where
 impl<V, I, F> Interactive for Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn interactivity(&mut self) -> &mut Interactivity<V> {
@@ -138,7 +138,7 @@ where
 impl<V, I, F> Hover for Svg<V, I, F>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
     F: ElementFocusability<V>,
 {
     fn set_hover_style(&mut self, group: Option<SharedString>, style: StyleRefinement) {
@@ -146,14 +146,14 @@ where
     }
 }
 
-impl<V, F> Click for Svg<V, Identified, F>
+impl<V, F> Click for Svg<V, StatefulInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
 {
 }
 
-impl<V, F> Active for Svg<V, Identified, F>
+impl<V, F> Active for Svg<V, StatefulInteractivity<V>, F>
 where
     V: 'static + Send + Sync,
     F: ElementFocusability<V>,
@@ -166,7 +166,7 @@ where
 impl<V, I> Focus for Svg<V, I, Focusable<V>>
 where
     V: 'static + Send + Sync,
-    I: ElementIdentity,
+    I: ElementInteractivity<V>,
 {
     fn focus_listeners(&mut self) -> &mut FocusListeners<Self::ViewState> {
         self.base.focus_listeners()