Optimize tree search with pre-built path index for O(1) vault lookup and eliminate filesystem traversal by indexing all directories and files during vault scan

backend/main.py

@@ -16,6 +16,7 @@ from backend.indexer import (
     build_index,
     reload_index,
     index,
+    path_index,
     get_vault_data,
     get_vault_names,
     find_file_in_index,
@@ -610,65 +611,40 @@ async def api_tree_search(
     q: str = Query("", description="Search query"),
     vault: str = Query("all", description="Vault filter"),
 ):
-    """Search for files and directories in the tree structure.
+    """Search for files and directories in the tree structure using pre-built index.
     
-    Searches through the file index for matching paths, returning
-    both files and their parent directories that match the query.
+    Uses the in-memory path index for instant filtering without filesystem access.
     
     Args:
         q: Search string to match against file/directory paths.
         vault: Vault name or "all" to search everywhere.
         
     Returns:
-        ``TreeSearchResponse`` with matching paths and their parent directories.
+        ``TreeSearchResponse`` with matching paths.
     """
     if not q:
         return {"query": q, "vault_filter": vault, "results": []}
     
     query_lower = q.lower()
     results = []
-    seen_paths = set()  # Avoid duplicates
     
-    vaults_to_search = [vault] if vault != "all" else list(index.keys())
+    vaults_to_search = [vault] if vault != "all" else list(path_index.keys())
     
     for vault_name in vaults_to_search:
-        vault_data = get_vault_data(vault_name)
-        if not vault_data:
-            continue
-            
-        vault_root = Path(vault_data["path"])
-        if not vault_root.exists():
-            continue
+        vault_paths = path_index.get(vault_name, [])
         
-        for fpath in vault_root.rglob("*"):
-            if fpath.name.startswith("."):
-                continue
-
-            try:
-                rel_path = str(fpath.relative_to(vault_root)).replace("\\", "/")
-                path_lower = rel_path.lower()
-                name_lower = fpath.name.lower()
-
-                if query_lower not in name_lower and query_lower not in path_lower:
-                    continue
-
-                entry_type = "directory" if fpath.is_dir() else "file"
-                entry_key = f"{vault_name}:{entry_type}:{rel_path}"
-                if entry_key in seen_paths:
-                    continue
-
-                seen_paths.add(entry_key)
+        for entry in vault_paths:
+            path_lower = entry["path"].lower()
+            name_lower = entry["name"].lower()
+            
+            if query_lower in name_lower or query_lower in path_lower:
                 results.append({
                     "vault": vault_name,
-                    "path": rel_path,
-                    "name": fpath.name,
-                    "type": entry_type,
-                    "matched_path": rel_path,
+                    "path": entry["path"],
+                    "name": entry["name"],
+                    "type": entry["type"],
+                    "matched_path": entry["path"],
                 })
-            except PermissionError:
-                continue
-            except Exception:
-                continue
     
     return {"query": q, "vault_filter": vault, "results": results}