From f95ec6080725fcd85ad30903666b4b3091797840 Mon Sep 17 00:00:00 2001
From: Antoine Beyeler <antoine@rerun.io>
Date: Wed, 29 Jan 2025 16:20:42 +0100
Subject: [PATCH] Move `VisitorFlowControl` to some accessible place since it's
 generally useful

---
 .../re_blueprint_tree/src/blueprint_tree.rs   |  3 +-
 crates/viewer/re_blueprint_tree/src/data.rs   | 29 +-----------------
 crates/viewer/re_viewer_context/src/lib.rs    |  2 ++
 .../src/visitor_flow_control.rs               | 30 +++++++++++++++++++
 4 files changed, 34 insertions(+), 30 deletions(-)
 create mode 100644 crates/viewer/re_viewer_context/src/visitor_flow_control.rs

diff --git a/crates/viewer/re_blueprint_tree/src/blueprint_tree.rs b/crates/viewer/re_blueprint_tree/src/blueprint_tree.rs
index 55268507aebf..817c3c11a29c 100644
--- a/crates/viewer/re_blueprint_tree/src/blueprint_tree.rs
+++ b/crates/viewer/re_blueprint_tree/src/blueprint_tree.rs
@@ -12,13 +12,12 @@ use re_ui::{
 use re_viewer_context::{
     contents_name_style, icon_for_container_kind, CollapseScope, ContainerId, Contents,
     DragAndDropFeedback, DragAndDropPayload, HoverHighlight, Item, ItemContext,
-    SystemCommandSender, ViewId, ViewerContext,
+    SystemCommandSender, ViewId, ViewerContext, VisitorControlFlow,
 };
 use re_viewport_blueprint::{ui::show_add_view_or_container_modal, ViewportBlueprint};
 
 use crate::data::{
     BlueprintTreeData, ContainerData, ContentsData, DataResultData, DataResultKind, ViewData,
-    VisitorControlFlow,
 };
 
 /// Holds the state of the blueprint tree UI.
diff --git a/crates/viewer/re_blueprint_tree/src/data.rs b/crates/viewer/re_blueprint_tree/src/data.rs
index bb836be37b8d..86449bb86d2e 100644
--- a/crates/viewer/re_blueprint_tree/src/data.rs
+++ b/crates/viewer/re_blueprint_tree/src/data.rs
@@ -20,7 +20,7 @@ use re_types::blueprint::components::Visible;
 use re_ui::filter_widget::FilterMatcher;
 use re_viewer_context::{
     CollapseScope, ContainerId, Contents, ContentsName, DataQueryResult, DataResultNode, Item,
-    ViewId, ViewerContext,
+    ViewId, ViewerContext, VisitorControlFlow,
 };
 use re_viewport_blueprint::{ContainerBlueprint, ViewBlueprint, ViewportBlueprint};
 
@@ -589,33 +589,6 @@ fn default_open_for_data_result(num_children: usize) -> bool {
 
 // ---
 
-/// Returned by the visitor closure to control tree traversal.
-pub enum VisitorControlFlow<B> {
-    /// Continue tree traversal
-    Continue,
-
-    /// Continue tree traversal but skip the children of the current item.
-    SkipBranch,
-
-    /// Stop traversal and return this value.
-    Break(B),
-}
-
-impl<B> VisitorControlFlow<B> {
-    /// Indicates whether we should visit the children of the current node—or entirely stop
-    /// traversal.
-    ///
-    /// Returning a [`ControlFlow`] enables key ergonomics by allowing the use of the short circuit
-    /// operator (`?`) while extracting the flag to control traversal of children.
-    fn visit_children(self) -> ControlFlow<B, bool> {
-        match self {
-            Self::Break(val) => ControlFlow::Break(val),
-            Self::Continue => ControlFlow::Continue(true),
-            Self::SkipBranch => ControlFlow::Continue(false),
-        }
-    }
-}
-
 /// Wrapper structure used for the closure of [`BlueprintTreeData::visit`] and friends.
 #[derive(Debug, Clone, Copy)]
 pub enum BlueprintTreeItem<'a> {
diff --git a/crates/viewer/re_viewer_context/src/lib.rs b/crates/viewer/re_viewer_context/src/lib.rs
index c45f189f6b26..62709a407864 100644
--- a/crates/viewer/re_viewer_context/src/lib.rs
+++ b/crates/viewer/re_viewer_context/src/lib.rs
@@ -36,6 +36,7 @@ pub mod test_context;
 
 // TODO(andreas): Move to its own crate?
 pub mod gpu_bridge;
+mod visitor_flow_control;
 
 pub use self::{
     annotations::{AnnotationMap, Annotations, ResolvedAnnotationInfo, ResolvedAnnotationInfos},
@@ -87,6 +88,7 @@ pub use self::{
         VisualizableFilterContext, VisualizerCollection, VisualizerQueryInfo, VisualizerSystem,
     },
     viewer_context::{RecordingConfig, ViewerContext},
+    visitor_flow_control::VisitorControlFlow,
 };
 
 pub use re_ui::UiLayout; // Historical reasons
diff --git a/crates/viewer/re_viewer_context/src/visitor_flow_control.rs b/crates/viewer/re_viewer_context/src/visitor_flow_control.rs
new file mode 100644
index 000000000000..5d8b5602f109
--- /dev/null
+++ b/crates/viewer/re_viewer_context/src/visitor_flow_control.rs
@@ -0,0 +1,30 @@
+//! Companion to [`std::ops::ControlFlow`] useful to implement visitor patterns.
+
+use std::ops::ControlFlow;
+
+/// Type to be returned by visitor closure to control the tree traversal flow.
+pub enum VisitorControlFlow<B> {
+    /// Continue tree traversal
+    Continue,
+
+    /// Continue tree traversal but skip the children of the current item.
+    SkipBranch,
+
+    /// Stop traversal and return this value.
+    Break(B),
+}
+
+impl<B> VisitorControlFlow<B> {
+    /// Indicates whether we should visit the children of the current node—or entirely stop
+    /// traversal.
+    ///
+    /// Returning a [`ControlFlow`] enables key ergonomics by allowing the use of the short circuit
+    /// operator (`?`) while extracting the flag to control traversal of children.
+    pub fn visit_children(self) -> ControlFlow<B, bool> {
+        match self {
+            Self::Break(val) => ControlFlow::Break(val),
+            Self::Continue => ControlFlow::Continue(true),
+            Self::SkipBranch => ControlFlow::Continue(false),
+        }
+    }
+}