Add get_file() to Namespace

devchat/engine/namespace.py

@@ -31,6 +31,27 @@ def is_valid_name(name: str) -> bool:
         pattern = r'^$|^(?!.*\.\.)[a-zA-Z0-9_-]+(\.[a-zA-Z0-9_-]+)*$'
         return bool(re.match(pattern, name))
 
+    def get_file(self, name: str, file: str) -> Optional[str]:
+        """
+        :param name: The command name in the namespace.
+        :param file: The target file name.
+        :return: The full path of the target file in the command directory.
+        """
+        if not self.is_valid_name(name):
+            return None
+        # Convert the dot-separated name to a path
+        path = os.path.join(*name.split('.'))
+        for branch in reversed(self.branches):
+            full_path = os.path.join(self.root_path, branch, path)
+            if os.path.isdir(full_path):
+                # If it exists and is a directory, check for the file
+                file_path = os.path.join(full_path, file)
+                if os.path.isfile(file_path):
+                    # If the file exists, return its path
+                    return file_path
+        # If no file is found, return None
+        return None
+
     def list_files(self, name: str) -> Optional[List[str]]:
         """
         :param name: The command name in the namespace.

tests/test_namespace.py

@@ -29,7 +29,44 @@ def test_is_valid_name():
     assert Namespace.is_valid_name('a>b') is False
 
 
-def test_get_files(tmp_path):
+def test_get_file(tmp_path):
+    # Create a Namespace instance with the temporary directory as the root path
+    namespace = Namespace(str(tmp_path))
+
+    # Test case 1: a file that exists
+    # Create a file in the 'usr' branch
+    os.makedirs(os.path.join(tmp_path, 'usr', 'a', 'b', 'c'), exist_ok=True)
+    file_path = os.path.join(tmp_path, 'usr', 'a', 'b', 'c', 'file1.txt')
+    with open(file_path, 'w', encoding='utf-8') as file:
+        file.write('test')
+    assert namespace.get_file('a.b.c', 'file1.txt') == file_path
+
+    # Test case 2: a file that doesn't exist
+    assert namespace.get_file('d.e.f', 'file2.txt') is None
+
+    # Test case 3: a file that exists in a later branch
+    # Create a file in the 'sys' branch
+    os.makedirs(os.path.join(tmp_path, 'usr', 'g', 'h', 'i'), exist_ok=True)
+    os.makedirs(os.path.join(tmp_path, 'sys', 'g', 'h', 'i'), exist_ok=True)
+    file_path = os.path.join(tmp_path, 'sys', 'g', 'h', 'i', 'file3.txt')
+    with open(file_path, 'w', encoding='utf-8') as file:
+        file.write('test')
+    assert namespace.get_file('g.h.i', 'file3.txt') == file_path
+
+    # Test case 4: a file in 'usr' overwrites the same in 'sys'
+    # Create the same file in the 'usr' and 'sys' branches
+    os.makedirs(os.path.join(tmp_path, 'usr', 'j', 'k', 'l'), exist_ok=True)
+    usr_file_path = os.path.join(tmp_path, 'usr', 'j', 'k', 'l', 'file4.txt')
+    os.makedirs(os.path.join(tmp_path, 'sys', 'j', 'k', 'l'), exist_ok=True)
+    sys_file_path = os.path.join(tmp_path, 'sys', 'j', 'k', 'l', 'file4.txt')
+    with open(usr_file_path, 'w', encoding='utf-8') as file:
+        file.write('test')
+    with open(sys_file_path, 'w', encoding='utf-8') as file:
+        file.write('test')
+    assert namespace.get_file('j.k.l', 'file4.txt') == usr_file_path
+
+
+def test_list_files(tmp_path):
     # Create a Namespace instance with the temporary directory as the root path
     namespace = Namespace(str(tmp_path))