Read-tree extract tree from object

ugit/base.py

@@ -1,4 +1,4 @@
-from pathlib import Path
+from pathlib import Path, PurePath
 
 from . import data
 
@@ -24,5 +24,36 @@ def write_tree(directory="."):
     return data.hash_object(tree.encode(), "tree")
 
 
+def _iter_tree_entries(oid):
+    if not oid:
+        return
+    tree = data.get_object(oid, "tree")
+    for entry in tree.decode().splitlines():
+        type_, oid, name = entry.split(" ", 2)
+        yield type_, oid, name
+
+
+def get_tree(oid, base_path=""):
+    result = {}
+    for type_, oid, name in _iter_tree_entries(oid):
+        assert "/" not in name
+        assert name not in ("..", ".")
+        path = base_path + name
+        if type_ == "blob":
+            result[path] = oid
+        elif type_ == "tree":
+            result.update(get_tree(oid, f"{path}/"))
+        else:
+            assert False, f"Unknown tree entry {type_}"
+    return result
+
+
+def read_tree(tree_oid):
+    for path, oid in get_tree(tree_oid, base_path="./").items():
+        Path.mkdir(PurePath.parent(path), exist_ok=True)
+        with open(path, "wb") as f:
+            f.write(data.get_object(oid))
+
+
 def is_ignored(path):
     return ".ugit" in path.split("/")