onboarding: Remove feature flag and old welcome crate (#36110)

Release Notes:

- N/A

---------

Co-authored-by: MrSubidubi <dev@bahn.sh>
Co-authored-by: Anthony <anthony@zed.dev>

crates/onboarding/src/multibuffer_hint.rs

@@ -0,0 +1,184 @@
+use std::collections::HashSet;
+use std::sync::OnceLock;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use db::kvp::KEY_VALUE_STORE;
+use gpui::{App, EntityId, EventEmitter, Subscription};
+use ui::{IconButtonShape, Tooltip, prelude::*};
+use workspace::item::{ItemEvent, ItemHandle};
+use workspace::{ToolbarItemEvent, ToolbarItemLocation, ToolbarItemView};
+
+pub struct MultibufferHint {
+    shown_on: HashSet<EntityId>,
+    active_item: Option<Box<dyn ItemHandle>>,
+    subscription: Option<Subscription>,
+}
+
+const NUMBER_OF_HINTS: usize = 10;
+
+const SHOWN_COUNT_KEY: &str = "MULTIBUFFER_HINT_SHOWN_COUNT";
+
+impl Default for MultibufferHint {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl MultibufferHint {
+    pub fn new() -> Self {
+        Self {
+            shown_on: Default::default(),
+            active_item: None,
+            subscription: None,
+        }
+    }
+}
+
+impl MultibufferHint {
+    fn counter() -> &'static AtomicUsize {
+        static SHOWN_COUNT: OnceLock<AtomicUsize> = OnceLock::new();
+        SHOWN_COUNT.get_or_init(|| {
+            let value: usize = KEY_VALUE_STORE
+                .read_kvp(SHOWN_COUNT_KEY)
+                .ok()
+                .flatten()
+                .and_then(|v| v.parse().ok())
+                .unwrap_or(0);
+
+            AtomicUsize::new(value)
+        })
+    }
+
+    fn shown_count() -> usize {
+        Self::counter().load(Ordering::Relaxed)
+    }
+
+    fn increment_count(cx: &mut App) {
+        Self::set_count(Self::shown_count() + 1, cx)
+    }
+
+    pub(crate) fn set_count(count: usize, cx: &mut App) {
+        Self::counter().store(count, Ordering::Relaxed);
+
+        db::write_and_log(cx, move || {
+            KEY_VALUE_STORE.write_kvp(SHOWN_COUNT_KEY.to_string(), format!("{}", count))
+        });
+    }
+
+    fn dismiss(&mut self, cx: &mut App) {
+        Self::set_count(NUMBER_OF_HINTS, cx)
+    }
+
+    /// Determines the toolbar location for this [`MultibufferHint`].
+    fn determine_toolbar_location(&mut self, cx: &mut Context<Self>) -> ToolbarItemLocation {
+        if Self::shown_count() >= NUMBER_OF_HINTS {
+            return ToolbarItemLocation::Hidden;
+        }
+
+        let Some(active_pane_item) = self.active_item.as_ref() else {
+            return ToolbarItemLocation::Hidden;
+        };
+
+        if active_pane_item.is_singleton(cx)
+            || active_pane_item.breadcrumbs(cx.theme(), cx).is_none()
+            || !active_pane_item.can_save(cx)
+        {
+            return ToolbarItemLocation::Hidden;
+        }
+
+        if self.shown_on.insert(active_pane_item.item_id()) {
+            Self::increment_count(cx);
+        }
+
+        ToolbarItemLocation::Secondary
+    }
+}
+
+impl EventEmitter<ToolbarItemEvent> for MultibufferHint {}
+
+impl ToolbarItemView for MultibufferHint {
+    fn set_active_pane_item(
+        &mut self,
+        active_pane_item: Option<&dyn ItemHandle>,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) -> ToolbarItemLocation {
+        cx.notify();
+        self.active_item = active_pane_item.map(|item| item.boxed_clone());
+
+        let Some(active_pane_item) = active_pane_item else {
+            return ToolbarItemLocation::Hidden;
+        };
+
+        let this = cx.entity().downgrade();
+        self.subscription = Some(active_pane_item.subscribe_to_item_events(
+            window,
+            cx,
+            Box::new(move |event, _, cx| {
+                if let ItemEvent::UpdateBreadcrumbs = event {
+                    this.update(cx, |this, cx| {
+                        cx.notify();
+                        let location = this.determine_toolbar_location(cx);
+                        cx.emit(ToolbarItemEvent::ChangeLocation(location))
+                    })
+                    .ok();
+                }
+            }),
+        ));
+
+        self.determine_toolbar_location(cx)
+    }
+}
+
+impl Render for MultibufferHint {
+    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+        h_flex()
+            .px_2()
+            .py_0p5()
+            .justify_between()
+            .bg(cx.theme().status().info_background.opacity(0.5))
+            .border_1()
+            .border_color(cx.theme().colors().border_variant)
+            .rounded_sm()
+            .overflow_hidden()
+            .child(
+                h_flex()
+                    .gap_0p5()
+                    .child(
+                        h_flex()
+                            .gap_2()
+                            .child(
+                                Icon::new(IconName::Info)
+                                    .size(IconSize::XSmall)
+                                    .color(Color::Muted),
+                            )
+                            .child(Label::new(
+                                "Edit and save files directly in the results multibuffer!",
+                            )),
+                    )
+                    .child(
+                        Button::new("open_docs", "Learn More")
+                            .icon(IconName::ArrowUpRight)
+                            .icon_size(IconSize::Small)
+                            .icon_color(Color::Muted)
+                            .icon_position(IconPosition::End)
+                            .on_click(move |_event, _, cx| {
+                                cx.open_url("https://zed.dev/docs/multibuffers")
+                            }),
+                    ),
+            )
+            .child(
+                IconButton::new("dismiss", IconName::Close)
+                    .shape(IconButtonShape::Square)
+                    .icon_size(IconSize::Small)
+                    .on_click(cx.listener(|this, _event, _, cx| {
+                        this.dismiss(cx);
+                        cx.emit(ToolbarItemEvent::ChangeLocation(
+                            ToolbarItemLocation::Hidden,
+                        ))
+                    }))
+                    .tooltip(Tooltip::text("Dismiss Hint")),
+            )
+            .into_any_element()
+    }
+}