feat: DirectoryTree expand by path

Author: Kalebe16

src/textual/widgets/_directory_tree.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from asyncio import Queue
+from asyncio import Queue, sleep
 from dataclasses import dataclass
 from pathlib import Path
 from typing import TYPE_CHECKING, Callable, ClassVar, Iterable, Iterator
@@ -56,7 +56,7 @@ class DirectoryTree(Tree[DirEntry]):
 
     DEFAULT_CSS = """
     DirectoryTree {
-        
+
         & > .directory-tree--folder {
             text-style: bold;
         }
@@ -70,11 +70,11 @@ class DirectoryTree(Tree[DirEntry]):
         }
 
         &:ansi {
-        
+
             & > .tree--guides {
-               color: transparent;              
+               color: transparent;
             }
-        
+
             & > .directory-tree--folder {
                 text-style: bold;
             }
@@ -452,6 +452,37 @@ def filter_paths(self, paths: Iterable[Path]) -> Iterable[Path]:
         """
         return paths
 
+    async def expand_by_path(self, target_path: Path) -> None:
+        """
+        Expands the directory tree to reveal the target path.
+
+        Args:
+            target_path: The filesystem path to reveal in the tree.
+        """
+
+        async def expand_to_target_path_recursively(
+            current_node: TreeNode, target_path: Path
+        ) -> None:
+            for child_node in current_node.children:
+                child_path = child_node.data.path  # Current directory path
+
+                if (
+                    target_path.is_relative_to(child_path)
+                    or child_path == target_path
+                ):
+                    child_node.expand()
+                    await sleep(
+                        0.1
+                    )  # Hack to wait for children to populate
+                    self.move_cursor(node=child_node)
+                    await expand_to_target_path_recursively(
+                        current_node=child_node, target_path=target_path
+                    )
+                    return
+
+        # Start expanding from the root of the directory tree
+        await expand_to_target_path_recursively(self.root, target_path)
+
     @staticmethod
     def _safe_is_dir(path: Path) -> bool:
         """Safely check if a path is a directory.