Track both parent and children on instances

server/src/rbx.rs

@@ -19,4 +19,6 @@ pub struct RbxInstance {
 
     /// All of the children of this instance. Order is relevant to preserve!
     pub children: Vec<Id>,
+
+    pub parent: Option<Id>,
 }

server/src/rbx_session.rs

@@ -9,6 +9,12 @@ use session::SessionConfig;
 use vfs_session::{VfsSession, FileItem, FileChange};
 use message_session::{Message, MessageSession};
 
+fn insert_if_missing<T: PartialEq>(vec: &mut Vec<T>, value: T) {
+    if !vec.contains(&value) {
+        vec.push(value);
+    }
+}
+
 // TODO: Rethink data structure and insertion/update behavior. Maybe break some
 // pieces off into a new object?
 fn file_to_instances(
@@ -16,6 +22,7 @@ fn file_to_instances(
     partition: &Partition,
     output: &mut HashMap<Id, RbxInstance>,
     instances_by_route: &mut HashMap<FileRoute, Id>,
+    parent_id: Option<Id>,
 ) -> (Id, Vec<Id>) {
     match file_item {
         FileItem::File { contents, route } => {
@@ -37,6 +44,7 @@ fn file_to_instances(
                 class_name: "StringValue".to_string(),
                 properties,
                 children: Vec::new(),
+                parent: parent_id,
             });
 
             (primary_id, vec![primary_id])
@@ -57,7 +65,7 @@ fn file_to_instances(
             let mut changed_ids = vec![primary_id];
 
             for child_file_item in children.values() {
-                let (child_id, mut child_changed_ids) = file_to_instances(child_file_item, partition, output, instances_by_route);
+                let (child_id, mut child_changed_ids) = file_to_instances(child_file_item, partition, output, instances_by_route, Some(primary_id));
 
                 child_ids.push(child_id);
                 changed_ids.push(child_id);
@@ -73,6 +81,7 @@ fn file_to_instances(
                 class_name: "Folder".to_string(),
                 properties: HashMap::new(),
                 children: child_ids,
+                parent: parent_id,
             });
 
             (primary_id, changed_ids)
@@ -110,16 +119,56 @@ impl RbxSession {
         }
     }
 
-    pub fn retrieve_instance<'a, 'b>(&'a self, id: Id, output: &'b mut HashMap<Id, &'a RbxInstance>) {
+    pub fn delete_instance(&mut self, id: Id) -> Vec<Id> {
-        let requested_instance = match self.instances.get(&id) {
+        let mut ids_to_visit = vec![id];
-            Some(instance) => instance,
+        let mut ids_deleted = Vec::new();
-            None => return,
+
+        for instance in self.instances.values_mut() {
+            match instance.children.iter().position(|&v| v == id) {
+                Some(index) => {
+                    instance.children.remove(index);
+                },
+                None => {},
+            }
+        }
+
+        loop {
+            let id = match ids_to_visit.pop() {
+                Some(id) => id,
+                None => break,
             };
 
-        output.insert(id, requested_instance);
+            match self.instances.get(&id) {
+                Some(instance) => ids_to_visit.extend_from_slice(&instance.children),
+                None => continue,
+            }
 
-        for child_id in &requested_instance.children {
+            self.instances.remove(&id);
-            self.retrieve_instance(*child_id, output);
+            ids_deleted.push(id);
+        }
+
+        ids_deleted
+    }
+
+    pub fn get_instance<'a, 'b>(&'a self, id: Id, output: &'b mut HashMap<Id, &'a RbxInstance>) {
+        let mut ids_to_visit = vec![id];
+
+        loop {
+            let id = match ids_to_visit.pop() {
+                Some(id) => id,
+                None => break,
+            };
+
+            match self.instances.get(&id) {
+                Some(instance) => {
+                    output.insert(id, instance);
+
+                    for child_id in &instance.children {
+                        ids_to_visit.push(*child_id);
+                    }
+                },
+                None => continue,
+            }
         }
     }
 
@@ -133,7 +182,21 @@ impl RbxSession {
                 route: Vec::new(),
             };
             let file_item = vfs_session.get_by_route(&route).unwrap();
-            let (root_id, _) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route);
+
+            let parent_id = match route.parent() {
+                Some(parent_route) => match self.instances_by_route.get(&parent_route) {
+                    Some(&parent_id) => Some(parent_id),
+                    None => None,
+                },
+                None => None,
+            };
+
+            let (root_id, _) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route, parent_id);
+
+            if let Some(parent_id) = parent_id {
+                insert_if_missing(&mut self.instances.get_mut(&parent_id).unwrap().children, root_id);
+            }
+
             self.partition_instances.insert(partition.name.clone(), root_id);
         }
     }
@@ -146,7 +209,20 @@ impl RbxSession {
             FileChange::Created(route) | FileChange::Updated(route) => {
                 let file_item = vfs_session.get_by_route(route).unwrap();
                 let partition = self.config.partitions.get(&route.partition).unwrap();
-                let (_, changed_ids) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route);
+
+                let parent_id = match route.parent() {
+                    Some(parent_route) => match self.instances_by_route.get(&parent_route) {
+                        Some(&parent_id) => Some(parent_id),
+                        None => None,
+                    },
+                    None => None,
+                };
+
+                let (root_id, changed_ids) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route, parent_id);
+
+                if let Some(parent_id) = parent_id {
+                    insert_if_missing(&mut self.instances.get_mut(&parent_id).unwrap().children, root_id);
+                }
 
                 let messages = changed_ids
                     .iter()
@@ -156,11 +232,11 @@ impl RbxSession {
                 self.message_session.push_messages(&messages);
             },
             FileChange::Deleted(route) => {
-                // TODO: Handle deletion of children here and in Moved case.
                 match self.instances_by_route.get(route) {
-                    Some(id) => {
+                    Some(&id) => {
-                        self.instances.remove(id);
+                        self.delete_instance(id);
-                        self.message_session.push_messages(&[Message::InstanceChanged { id: *id }]);
+                        self.instances_by_route.remove(route);
+                        self.message_session.push_messages(&[Message::InstanceChanged { id }]);
                     },
                     None => (),
                 }
@@ -169,16 +245,30 @@ impl RbxSession {
                 let mut messages = Vec::new();
 
                 match self.instances_by_route.get(from_route) {
-                    Some(id) => {
+                    Some(&id) => {
-                        self.instances.remove(id);
+                        self.delete_instance(id);
-                        messages.push(Message::InstanceChanged { id: *id });
+                        self.instances_by_route.remove(from_route);
+                        messages.push(Message::InstanceChanged { id });
                     },
                     None => (),
                 }
 
                 let file_item = vfs_session.get_by_route(to_route).unwrap();
                 let partition = self.config.partitions.get(&to_route.partition).unwrap();
-                let (_, changed_ids) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route);
+
+                let parent_id = match to_route.parent() {
+                    Some(parent_route) => match self.instances_by_route.get(&parent_route) {
+                        Some(&parent_id) => Some(parent_id),
+                        None => None,
+                    },
+                    None => None,
+                };
+
+                let (root_id, changed_ids) = file_to_instances(file_item, partition, &mut self.instances, &mut self.instances_by_route, parent_id);
+
+                if let Some(parent_id) = parent_id {
+                    insert_if_missing(&mut self.instances.get_mut(&parent_id).unwrap().children, root_id);
+                }
 
                 for id in changed_ids {
                     messages.push(Message::InstanceChanged { id });

server/src/web.rs

@@ -162,7 +162,7 @@ pub fn start(config: WebConfig) {
                 let mut instances = HashMap::new();
 
                 for requested_id in &requested_ids {
-                    rbx_session.retrieve_instance(*requested_id, &mut instances);
+                    rbx_session.get_instance(*requested_id, &mut instances);
                 }
 
                 Response::json(&ReadResponse {