Flesh out reconciler routine

server/src/rbx_snapshot.rs

@@ -64,4 +64,73 @@ fn reify_child(snapshot: &RbxSnapshotInstance, tree: &mut RbxTree, parent_id: Rb
     for child in &snapshot.children {
         reify_child(child, tree, id);
     }
+}
+
+fn reconcile_instance_properties(instance: &mut RbxInstance, snapshot: &RbxSnapshotInstance) -> bool {
+    let mut has_diffs = false;
+
+    if instance.name != snapshot.name {
+        instance.name = snapshot.name.to_string();
+        has_diffs = true;
+    }
+
+    if instance.class_name != snapshot.class_name {
+        instance.class_name = snapshot.class_name.to_string();
+        has_diffs = true;
+    }
+
+    let mut property_updates = HashMap::new();
+
+    for (key, instance_value) in &instance.properties {
+        match snapshot.properties.get(key) {
+            Some(snapshot_value) => {
+                if &snapshot_value.to_rbx_value() != instance_value {
+                    property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+                }
+            },
+            None => {
+                property_updates.insert(key.clone(), None);
+            },
+        }
+    }
+
+    for (key, snapshot_value) in &snapshot.properties {
+        if property_updates.contains_key(key) {
+            continue;
+        }
+
+        match instance.properties.get(key) {
+            Some(instance_value) => {
+                if &snapshot_value.to_rbx_value() != instance_value {
+                    property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+                }
+            },
+            None => {
+                property_updates.insert(key.clone(), Some(snapshot_value.clone()));
+            },
+        }
+    }
+
+    has_diffs = has_diffs || !property_updates.is_empty();
+
+    for (key, change) in property_updates.drain() {
+        match change {
+            Some(value) => instance.properties.insert(key, value.to_rbx_value()),
+            None => instance.properties.remove(&key),
+        };
+    }
+
+    has_diffs
+}
+
+fn reconcile_instance_children(tree: &mut RbxTree, id: RbxId, snapshot: &RbxSnapshotInstance, changed_ids: &mut Vec<RbxId>) {
+    // TODO: enumerate and match up children, update props, construct and delete IDs
+}
+
+pub fn reconcile_subtree(tree: &mut RbxTree, id: RbxId, snapshot: &RbxSnapshotInstance, changed_ids: &mut Vec<RbxId>) {
+    if reconcile_instance_properties(tree.get_instance_mut().unwrap(), snapshot) {
+        changed_ids.push(id);
+    }
+
+    reconcile_instance_children(tree, id, snapshot, changed_ids);
 }