Refactor mostly complete

server/src/snapshot_reconciler.rs

@@ -0,0 +1,308 @@
+use std::{
+    str,
+    borrow::Cow,
+    collections::{HashMap, HashSet},
+    fmt,
+    path::PathBuf,
+};
+
+use rbx_tree::{RbxTree, RbxId, RbxInstanceProperties, RbxValue};
+use serde_derive::{Serialize, Deserialize};
+
+use crate::{
+    path_map::PathMap,
+    project::InstanceProjectNodeMetadata,
+};
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct InstanceChanges {
+    pub added: HashSet<RbxId>,
+    pub removed: HashSet<RbxId>,
+    pub updated: HashSet<RbxId>,
+}
+
+impl fmt::Display for InstanceChanges {
+    fn fmt(&self, output: &mut fmt::Formatter) -> fmt::Result {
+        writeln!(output, "InstanceChanges {{")?;
+
+        if !self.added.is_empty() {
+            writeln!(output, "    Added:")?;
+            for id in &self.added {
+                writeln!(output, "        {}", id)?;
+            }
+        }
+
+        if !self.removed.is_empty() {
+            writeln!(output, "    Removed:")?;
+            for id in &self.removed {
+                writeln!(output, "        {}", id)?;
+            }
+        }
+
+        if !self.updated.is_empty() {
+            writeln!(output, "    Updated:")?;
+            for id in &self.updated {
+                writeln!(output, "        {}", id)?;
+            }
+        }
+
+        writeln!(output, "}}")
+    }
+}
+
+impl InstanceChanges {
+    pub fn is_empty(&self) -> bool {
+        self.added.is_empty() && self.removed.is_empty() && self.updated.is_empty()
+    }
+}
+
+#[derive(Debug)]
+pub struct RbxSnapshotInstance<'a> {
+    pub name: Cow<'a, str>,
+    pub class_name: Cow<'a, str>,
+    pub properties: HashMap<String, RbxValue>,
+    pub children: Vec<RbxSnapshotInstance<'a>>,
+    pub source_path: Option<PathBuf>,
+    pub metadata: Option<InstanceProjectNodeMetadata>,
+}
+
+pub fn snapshot_from_tree(tree: &RbxTree, id: RbxId) -> Option<RbxSnapshotInstance<'static>> {
+    let instance = tree.get_instance(id)?;
+
+    let mut children = Vec::new();
+    for &child_id in instance.get_children_ids() {
+        children.push(snapshot_from_tree(tree, child_id)?);
+    }
+
+    Some(RbxSnapshotInstance {
+        name: Cow::Owned(instance.name.to_owned()),
+        class_name: Cow::Owned(instance.class_name.to_owned()),
+        properties: instance.properties.clone(),
+        children,
+        source_path: None,
+        metadata: None,
+    })
+}
+
+pub fn reify_root(
+    snapshot: &RbxSnapshotInstance,
+    path_map: &mut PathMap<RbxId>,
+    instance_metadata_map: &mut HashMap<RbxId, InstanceProjectNodeMetadata>,
+    changes: &mut InstanceChanges,
+) -> RbxTree {
+    let instance = reify_core(snapshot);
+    let mut tree = RbxTree::new(instance);
+    let root_id = tree.get_root_id();
+
+    if let Some(source_path) = &snapshot.source_path {
+        path_map.insert(source_path.clone(), root_id);
+    }
+
+    if let Some(metadata) = &snapshot.metadata {
+        instance_metadata_map.insert(root_id, metadata.clone());
+    }
+
+    changes.added.insert(root_id);
+
+    for child in &snapshot.children {
+        reify_subtree(child, &mut tree, root_id, path_map, instance_metadata_map, changes);
+    }
+
+    tree
+}
+
+pub fn reify_subtree(
+    snapshot: &RbxSnapshotInstance,
+    tree: &mut RbxTree,
+    parent_id: RbxId,
+    path_map: &mut PathMap<RbxId>,
+    instance_metadata_map: &mut HashMap<RbxId, InstanceProjectNodeMetadata>,
+    changes: &mut InstanceChanges,
+) {
+    let instance = reify_core(snapshot);
+    let id = tree.insert_instance(instance, parent_id);
+
+    if let Some(source_path) = &snapshot.source_path {
+        path_map.insert(source_path.clone(), id);
+    }
+
+    if let Some(metadata) = &snapshot.metadata {
+        instance_metadata_map.insert(id, metadata.clone());
+    }
+
+    changes.added.insert(id);
+
+    for child in &snapshot.children {
+        reify_subtree(child, tree, id, path_map, instance_metadata_map, changes);
+    }
+}
+
+pub fn reconcile_subtree(
+    tree: &mut RbxTree,
+    id: RbxId,
+    snapshot: &RbxSnapshotInstance,
+    path_map: &mut PathMap<RbxId>,
+    instance_metadata_map: &mut HashMap<RbxId, InstanceProjectNodeMetadata>,
+    changes: &mut InstanceChanges,
+) {
+    if let Some(source_path) = &snapshot.source_path {
+        path_map.insert(source_path.clone(), id);
+    }
+
+    if let Some(metadata) = &snapshot.metadata {
+        instance_metadata_map.insert(id, metadata.clone());
+    }
+
+    if reconcile_instance_properties(tree.get_instance_mut(id).unwrap(), snapshot) {
+        changes.updated.insert(id);
+    }
+
+    reconcile_instance_children(tree, id, snapshot, path_map, instance_metadata_map, changes);
+}
+
+fn reify_core(snapshot: &RbxSnapshotInstance) -> RbxInstanceProperties {
+    let mut properties = HashMap::new();
+
+    for (key, value) in &snapshot.properties {
+        properties.insert(key.clone(), value.clone());
+    }
+
+    let instance = RbxInstanceProperties {
+        name: snapshot.name.to_string(),
+        class_name: snapshot.class_name.to_string(),
+        properties,
+    };
+
+    instance
+}
+
+fn reconcile_instance_properties(instance: &mut RbxInstanceProperties, 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 != 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 != 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),
+            None => instance.properties.remove(&key),
+        };
+    }
+
+    has_diffs
+}
+
+fn reconcile_instance_children(
+    tree: &mut RbxTree,
+    id: RbxId,
+    snapshot: &RbxSnapshotInstance,
+    path_map: &mut PathMap<RbxId>,
+    instance_metadata_map: &mut HashMap<RbxId, InstanceProjectNodeMetadata>,
+    changes: &mut InstanceChanges,
+) {
+    let mut visited_snapshot_indices = HashSet::new();
+
+    let mut children_to_update: Vec<(RbxId, &RbxSnapshotInstance)> = Vec::new();
+    let mut children_to_add: Vec<&RbxSnapshotInstance> = Vec::new();
+    let mut children_to_remove: Vec<RbxId> = Vec::new();
+
+    let children_ids = tree.get_instance(id).unwrap().get_children_ids();
+
+    // Find all instances that were removed or updated, which we derive by
+    // trying to pair up existing instances to snapshots.
+    for &child_id in children_ids {
+        let child_instance = tree.get_instance(child_id).unwrap();
+
+        // Locate a matching snapshot for this instance
+        let mut matching_snapshot = None;
+        for (snapshot_index, child_snapshot) in snapshot.children.iter().enumerate() {
+            if visited_snapshot_indices.contains(&snapshot_index) {
+                continue;
+            }
+
+            // We assume that instances with the same name are probably pretty
+            // similar. This heuristic is similar to React's reconciliation
+            // strategy.
+            if child_snapshot.name == child_instance.name {
+                visited_snapshot_indices.insert(snapshot_index);
+                matching_snapshot = Some(child_snapshot);
+                break;
+            }
+        }
+
+        match matching_snapshot {
+            Some(child_snapshot) => {
+                children_to_update.push((child_instance.get_id(), child_snapshot));
+            },
+            None => {
+                children_to_remove.push(child_instance.get_id());
+            },
+        }
+    }
+
+    // Find all instancs that were added, which is just the snapshots we didn't
+    // match up to existing instances above.
+    for (snapshot_index, child_snapshot) in snapshot.children.iter().enumerate() {
+        if !visited_snapshot_indices.contains(&snapshot_index) {
+            children_to_add.push(child_snapshot);
+        }
+    }
+
+    for child_snapshot in &children_to_add {
+        reify_subtree(child_snapshot, tree, id, path_map, instance_metadata_map, changes);
+    }
+
+    for child_id in &children_to_remove {
+        if let Some(subtree) = tree.remove_instance(*child_id) {
+            for id in subtree.iter_all_ids() {
+                instance_metadata_map.remove(&id);
+                changes.removed.insert(id);
+            }
+        }
+    }
+
+    for (child_id, child_snapshot) in &children_to_update {
+        reconcile_subtree(tree, *child_id, child_snapshot, path_map, instance_metadata_map, changes);
+    }
+}