Update overlay_directories.py

utils/bazel/overlay_directories.py

@@ -4,8 +4,6 @@
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-# This is copied from llvm-project's utils/bazel/overlay_directories.py
-
 """Overlays two directories into a target directory using symlinks.
 
 Tries to minimize the number of symlinks created (that is, does not symlink
@@ -20,77 +18,77 @@
 import sys
 
 
-def _check_python_version():
-  if sys.version_info[0] < 3:
-    raise RuntimeError(
-        "Must be invoked with a python 3 interpreter but was %s" %
-        sys.executable)
+def check_python_version():
+    """Checks if the Python version is at least 3."""
+    if sys.version_info[0] < 3:
+        raise RuntimeError(
+            "Must be invoked with a python 3 interpreter but was %s" %
+            sys.executable)
 
 
-def _check_dir_exists(path):
-  if not os.path.isdir(path):
-    raise OSError(errno.ENOENT, os.strerror(errno.ENOENT), path)
+def check_dir_exists(path):
+    """Checks if the directory exists."""
+    if not os.path.isdir(path):
+        raise FileNotFoundError(errno.ENOENT, os.strerror(errno.ENOENT), path)
 
 
 def parse_arguments():
-  parser = argparse.ArgumentParser(description="""
+    """Parses command-line arguments."""
+    parser = argparse.ArgumentParser(description="""
     Overlays two directories into a target directory using symlinks.
 
     Tries to minimize the number of symlinks created (that is, does not symlink
     every single file). Symlinks every file in the overlay directory. Only
     symlinks individual files in the source directory if their parent directory
     is also contained in the overlay directory tree.
     """)
-  parser.add_argument(
-      "--src",
-      required=True,
-      help="Directory that contains most of the content to symlink.")
-  parser.add_argument(
-      "--overlay",
-      required=True,
-      help="Directory to overlay on top of the source directory.")
-  parser.add_argument(
-      "--target",
-      required=True,
-      help="Directory in which to place the fused symlink directories.")
+    parser.add_argument(
+        "--src",
+        required=True,
+        help="Directory that contains most of the content to symlink.")
+    parser.add_argument(
+        "--overlay",
+        required=True,
+        help="Directory to overlay on top of the source directory.")
+    parser.add_argument(
+        "--target",
+        required=True,
+        help="Directory in which to place the fused symlink directories.")
 
-  args = parser.parse_args()
+    args = parser.parse_args()
 
-  _check_dir_exists(args.target)
-  _check_dir_exists(args.overlay)
-  _check_dir_exists(args.src)
+    check_dir_exists(args.target)
+    check_dir_exists(args.overlay)
+    check_dir_exists(args.src)
 
-  return args
+    return args
 
 
-def _symlink_abs(from_path, to_path):
-  if not os.path.exists(to_path):
-    os.symlink(os.path.abspath(from_path), os.path.abspath(to_path))
+def symlink_abs(from_path, to_path):
+    """Creates an absolute symlink from 'from_path' to 'to_path'."""
+    if not os.path.exists(to_path):
+        os.symlink(os.path.abspath(from_path), os.path.abspath(to_path))
 
 
 def main(args):
-  for root, dirs, files in os.walk(args.overlay):
-    # We could do something more intelligent here and only symlink individual
-    # files if the directory is present in both overlay and src. This could also
-    # be generalized to an arbitrary number of directories without any
-    # "src/overlay" distinction. In the current use case we only have two and
-    # the overlay directory is always small, so putting that off for now.
-    rel_root = os.path.relpath(root, start=args.overlay)
-    if rel_root != ".":
-      os.mkdir(os.path.join(args.target, rel_root))
-
-    for file in files:
-      relpath = os.path.join(rel_root, file)
-      _symlink_abs(os.path.join(args.overlay, relpath),
-                   os.path.join(args.target, relpath))
-
-    for src_entry in os.listdir(os.path.join(args.src, rel_root)):
-      if src_entry not in dirs:
-        relpath = os.path.join(rel_root, src_entry)
-        _symlink_abs(os.path.join(args.src, relpath),
-                     os.path.join(args.target, relpath))
+    """Main function to overlay directories using symlinks."""
+    for root, dirs, files in os.walk(args.overlay):
+        rel_root = os.path.relpath(root, start=args.overlay)
+        if rel_root != ".":
+            os.mkdir(os.path.join(args.target, rel_root))
+
+        for file in files:
+            relpath = os.path.join(rel_root, file)
+            symlink_abs(os.path.join(args.overlay, relpath),
+                        os.path.join(args.target, relpath))
+
+        for src_entry in os.listdir(os.path.join(args.src, rel_root)):
+            if src_entry not in dirs:
+                relpath = os.path.join(rel_root, src_entry)
+                symlink_abs(os.path.join(args.src, relpath),
+                            os.path.join(args.target, relpath))
 
 
 if __name__ == "__main__":
-  _check_python_version()
-  main(parse_arguments())
+    check_python_version()
+    main(parse_arguments())