collapse immediate children on '='

Summary:
It's often useful to collapse all children of the currently selected cgroup.
Currently, the only way to achieve that is to go manually through all of them and collapse them with `<Enter>`
Add a new hotkey '=' to do the same.

Reviewed By: dschatzberg

Differential Revision: D63396627

fbshipit-source-id: b022d83e52ab4359ca6c90e06e25cefa61b63178

below/model/src/cgroup.rs

@@ -108,11 +108,8 @@ impl QueriableContainer for CgroupModel {
         Some((&s[..idx_end + 1], &s[idx_end + 2..]))
     }
     fn get_item(&self, idx: &Self::Idx) -> Option<&SingleCgroupModel> {
-        let mut model = self;
-        for part in idx.path.iter() {
-            model = model.children.get(part.as_str())?;
-        }
-        Some(&model.data)
+        self.get_by_path_iter(idx.path.iter())
+            .map(|model| &model.data)
     }
 }
 
@@ -274,6 +271,17 @@ impl CgroupModel {
         });
         self
     }
+
+    fn get_by_path_iter(
+        &self,
+        mut path: impl Iterator<Item = impl AsRef<str>>,
+    ) -> Option<&CgroupModel> {
+        path.try_fold(self, |cur, p| cur.children.get(p.as_ref()))
+    }
+
+    pub fn get_by_path_str(&self, path: &str) -> Option<&CgroupModel> {
+        self.get_by_path_iter(path.split('/').filter(|x| !x.is_empty()))
+    }
 }
 
 impl Nameable for CgroupModel {

below/view/src/cgroup_view.rs

@@ -191,6 +191,17 @@ impl CgroupState {
         self.uncollapse_cgroup(cgroup.as_str());
         self.cgroup_to_focus = Some(cgroup);
     }
+
+    pub fn collapse_selected_cgroup_children(&mut self) {
+        if let Some(cur) = self
+            .get_model()
+            .get_by_path_str(&self.current_selected_cgroup)
+        {
+            self.collapsed_cgroups
+                .borrow_mut()
+                .extend(cur.children.iter().map(|c| &c.data.full_path).cloned());
+        }
+    }
 }
 
 // TODO: Make CgroupView a collection of CgroupTab
@@ -336,6 +347,11 @@ impl CgroupView {
             view.state.borrow_mut().set_reverse(true);
             view.refresh(c)
         })
+        .on_event('=', |c| {
+            let mut view = Self::get_cgroup_view(c);
+            view.state.borrow_mut().collapse_selected_cgroup_children();
+            view.refresh(c);
+        })
         .with_name(Self::get_view_name())
     }
 
@@ -394,14 +410,10 @@ impl ViewBridge for CgroupView {
         } else {
             view.get_tag_from_tab_idx(current_tab, selected_column)
         };
-        let field_str = selected_key
-            .split('/')
-            // Ignore leading slash
-            .skip(1)
-            // Traverse cgroup model tree to find matching model, or None
-            .try_fold(view.model.borrow(), |model, cgroup_name| {
-                Ref::filter_map(model, |model| model.children.get(cgroup_name)).ok()
-            })
+        let field_str = view
+            .model
+            .borrow()
+            .get_by_path_str(selected_key)
             .and_then(|model| model.data.query(&tag))
             .map_or("?".to_string(), |field| field.to_string());
         format!(" {} : {} ", tag, field_str)

below/view/src/help_menu.rs

@@ -195,6 +195,7 @@ fn fill_reserved(v: &mut LinearLayout) {
         " <Home>         - scroll to top of primary display\n",
         " <End>          - scroll to end of primary display\n",
         " <Enter>        - collapse/expand cgroup tree, submit command if command palette activated\n",
+        " '='            - collapse immediate children of selected cgroup\n",
         " <Ctrl>-r       - refresh the screen",
         " 'P'            - sort by pid (process view only)\n",
         " 'N'            - sort by name (process view only)\n",