extract header from code

.cross_sync/generate.py

@@ -23,11 +23,27 @@
 """
 
 
+def extract_header_comments(file_path) -> str:
+    """
+    Extract the file header. Header is defined as the top-level
+    comments before any code or imports
+    """
+    header = []
+    with open(file_path, "r") as f:
+        for line in f:
+            if line.startswith("#") or line.strip() == "":
+                header.append(line)
+            else:
+                break
+    return "".join(header)
+
+
 class CrossSyncOutputFile:
 
-    def __init__(self, file_path: str, ast_tree):
-        self.file_path = file_path
+    def __init__(self, output_path: str, ast_tree, header: str | None = None):
+        self.output_path = output_path
         self.tree = ast_tree
+        self.header = header or ""
 
     def render(self, with_black=True, save_to_disk: bool = False) -> str:
         """
@@ -37,24 +53,7 @@ def render(self, with_black=True, save_to_disk: bool = False) -> str:
             with_black: whether to run the output through black before returning
             save_to_disk: whether to write the output to the file path
         """
-        header = (
-            "# Copyright 2024 Google LLC\n"
-            "#\n"
-            '# Licensed under the Apache License, Version 2.0 (the "License");\n'
-            "# you may not use this file except in compliance with the License.\n"
-            "# You may obtain a copy of the License at\n"
-            "#\n"
-            "#     http://www.apache.org/licenses/LICENSE-2.0\n"
-            "#\n"
-            "# Unless required by applicable law or agreed to in writing, software\n"
-            '# distributed under the License is distributed on an "AS IS" BASIS,\n'
-            "# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n"
-            "# See the License for the specific language governing permissions and\n"
-            "# limitations under the License.\n"
-            "#\n"
-            "# This file is automatically generated by CrossSync. Do not edit manually.\n"
-        )
-        full_str = header + ast.unparse(self.tree)
+        full_str = self.header + ast.unparse(self.tree)
         if with_black:
             import black  # type: ignore
             import autoflake  # type: ignore
@@ -65,8 +64,8 @@ def render(self, with_black=True, save_to_disk: bool = False) -> str:
             )
         if save_to_disk:
             import os
-            os.makedirs(os.path.dirname(self.file_path), exist_ok=True)
-            with open(self.file_path, "w") as f:
+            os.makedirs(os.path.dirname(self.output_path), exist_ok=True)
+            with open(self.output_path, "w") as f:
                 f.write(full_str)
         return full_str
 
@@ -87,7 +86,8 @@ def convert_files_in_dir(directory: str) -> set[CrossSyncOutputFile]:
         if output_path is not None:
             # contains __CROSS_SYNC_OUTPUT__ annotation
             converted_tree = file_transformer.visit(ast_tree)
-            artifacts.add(CrossSyncOutputFile(output_path, converted_tree))
+            header = extract_header_comments(file_path)
+            artifacts.add(CrossSyncOutputFile(output_path, converted_tree, header))
     # return set of output artifacts
     return artifacts