Add desktop navigation tree

crates/storage/src/read.rs

@@ -15,12 +15,49 @@ use crate::{
 
 const EXTENSIONS_DIRECTORY: &str = ".extensions";
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
 pub enum TreeNodeKind {
     Directory,
     Entry,
 }
 
+/// Stable storage-owned identity for a navigation tree object.
+///
+/// Frontends retain this value across refreshed [`TreeModel`] instances
+/// instead of reconstructing identity from rendered labels.
+#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum TreeNodeId {
+    Directory(DirectoryPath),
+    Entry(EntryPath),
+}
+
+impl TreeNodeId {
+    pub fn path(&self) -> &Path {
+        match self {
+            Self::Directory(path) => path.as_path(),
+            Self::Entry(path) => path.as_path(),
+        }
+    }
+
+    pub fn kind(&self) -> TreeNodeKind {
+        match self {
+            Self::Directory(_) => TreeNodeKind::Directory,
+            Self::Entry(_) => TreeNodeKind::Entry,
+        }
+    }
+
+    pub fn is_directory(&self) -> bool {
+        matches!(self, Self::Directory(_))
+    }
+
+    pub fn entry(&self) -> Option<&EntryPath> {
+        match self {
+            Self::Entry(path) => Some(path),
+            Self::Directory(_) => None,
+        }
+    }
+}
+
 /// Presentation-safe state calculated by storage services for a tree object.
 /// Frontends render these flags and never infer them from names or paths.
 #[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
@@ -55,8 +92,7 @@ impl TreeNodeIndicators {
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct TreeNode {
     name: String,
-    path: String,
-    kind: TreeNodeKind,
+    id: TreeNodeId,
     indicators: TreeNodeIndicators,
     children: Vec<TreeNode>,
 }
@@ -67,11 +103,18 @@ impl TreeNode {
     }
 
     pub fn path(&self) -> &str {
-        &self.path
+        self.id
+            .path()
+            .to_str()
+            .expect("tree construction rejects non-UTF-8 paths")
     }
 
     pub fn kind(&self) -> TreeNodeKind {
-        self.kind
+        self.id.kind()
+    }
+
+    pub fn id(&self) -> &TreeNodeId {
+        &self.id
     }
 
     pub fn indicators(&self) -> TreeNodeIndicators {
@@ -630,8 +673,10 @@ fn finalize_children(node: MutableNode, parent: &Path) -> Result<Vec<TreeNode>,
             let children = finalize_children(child, &path)?;
             Ok(TreeNode {
                 name,
-                path: path_text(&path)?,
-                kind,
+                id: match kind {
+                    TreeNodeKind::Directory => TreeNodeId::Directory(DirectoryPath::parse(&path)?),
+                    TreeNodeKind::Entry => TreeNodeId::Entry(EntryPath::parse(&path)?),
+                },
                 indicators: TreeNodeIndicators::default(),
                 children,
             })