Remove Editor::find_or_create

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

crates/workspace/src/workspace.rs

@@ -195,6 +195,16 @@ pub trait Item: View {
     }
 }
 
+pub trait ProjectItem: Item {
+    type Item: project::Item;
+
+    fn for_project_item(
+        project: ModelHandle<Project>,
+        item: ModelHandle<Self::Item>,
+        cx: &mut ViewContext<Self>,
+    ) -> Self;
+}
+
 pub trait ItemHandle: 'static {
     fn tab_content(&self, style: &theme::Tab, cx: &AppContext) -> ElementBox;
     fn project_path(&self, cx: &AppContext) -> Option<ProjectPath>;
@@ -833,6 +843,31 @@ impl Workspace {
         })
     }
 
+    pub fn open_project_item<T>(
+        &mut self,
+        project_item: ModelHandle<T::Item>,
+        cx: &mut ViewContext<Self>,
+    ) -> ViewHandle<T>
+    where
+        T: ProjectItem,
+    {
+        use project::Item as _;
+
+        if let Some(item) = project_item
+            .read(cx)
+            .entry_id(cx)
+            .and_then(|entry_id| self.active_pane().read(cx).item_for_entry(entry_id))
+            .and_then(|item| item.downcast())
+        {
+            self.activate_item(&item, cx);
+            return item;
+        }
+
+        let item = cx.add_view(|cx| T::for_project_item(self.project().clone(), project_item, cx));
+        self.add_item(Box::new(item.clone()), cx);
+        item
+    }
+
     pub fn activate_item(&mut self, item: &dyn ItemHandle, cx: &mut ViewContext<Self>) -> bool {
         let result = self.panes.iter().find_map(|pane| {
             if let Some(ix) = pane.read(cx).index_for_item(item) {