1 files changed, 119 insertions, 0 deletions
diff --git a/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py b/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py
new file mode 100755
index 00000000..15f0e3ba
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+++ b/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py
@@ -0,0 +1,119 @@
+#!/usr/bin/env python
+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Downgrades *.mojom files to the old mojo types for remotes and receivers."""
+
+import argparse
+import fnmatch
+import os
+import re
+import shutil
+import sys
+import tempfile
+
+# List of patterns and replacements to match and use against the contents of a
+# mojo file. Each replacement string will be used with Python string's format()
+# function, so the '{}' substring is used to mark where the mojo type should go.
+_MOJO_REPLACEMENTS = {
+    r'pending_remote': r'{}',
+    r'pending_receiver': r'{}&',
+    r'pending_associated_remote': r'associated {}',
+    r'pending_associated_receiver': r'associated {}&',
+}
+
+# Pre-compiled regular expression that matches against any of the replacements.
+_REGEXP_PATTERN = re.compile(
+    r'|'.join(
+        ['{}\s*<\s*(.*?)\s*>'.format(k) for k in _MOJO_REPLACEMENTS.keys()]),
+    flags=re.DOTALL)
+
+
+def ReplaceFunction(match_object):
+  """Returns the right replacement for the string matched against the regexp."""
+  for index, (match, repl) in enumerate(_MOJO_REPLACEMENTS.items(), 1):
+    if match_object.group(0).startswith(match):
+      return repl.format(match_object.group(index))
+
+
+def DowngradeFile(path, output_dir=None):
+  """Downgrades the mojom file specified by |path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  # Use a temporary file to dump the new contents after replacing the patterns.
+  with open(path) as src_mojo_file:
+    with tempfile.NamedTemporaryFile(mode='w', delete=False) as tmp_mojo_file:
+      tmp_contents = _REGEXP_PATTERN.sub(ReplaceFunction, src_mojo_file.read())
+      tmp_mojo_file.write(tmp_contents)
+
+  # Files should be placed in the desired output directory
+  if output_dir:
+    output_filepath = os.path.join(output_dir, os.path.basename(path))
+    if not os.path.exists(output_dir):
+      os.makedirs(output_dir)
+  else:
+    output_filepath = path
+
+  # Write the new contents preserving the original file's attributes.
+  shutil.copystat(path, tmp_mojo_file.name)
+  shutil.move(tmp_mojo_file.name, output_filepath)
+
+  # Make sure to "touch" the new file so that access, modify and change times
+  # are always newer than the source file's, otherwise Modify time will be kept
+  # as per the call to shutil.copystat(), causing unnecessary generations of the
+  # output file in subsequent builds due to ninja considering it dirty.
+  os.utime(output_filepath, None)
+
+
+def DowngradeDirectory(path, output_dir=None):
+  """Downgrades mojom files inside directory |path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  # We don't have recursive glob.glob() nor pathlib.Path.rglob() in Python 2.7
+  mojom_filepaths = []
+  for dir_path, _, filenames in os.walk(path):
+    for filename in fnmatch.filter(filenames, "*mojom"):
+      mojom_filepaths.append(os.path.join(dir_path, filename))
+
+  for path in mojom_filepaths:
+    absolute_dirpath = os.path.dirname(os.path.abspath(path))
+    if output_dir:
+      dest_dirpath = output_dir + absolute_dirpath
+    else:
+      dest_dirpath = absolute_dirpath
+    DowngradeFile(path, dest_dirpath)
+
+
+def DowngradePath(src_path, output_dir=None):
+  """Downgrades the mojom files pointed by |src_path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  if os.path.isdir(src_path):
+    DowngradeDirectory(src_path, output_dir)
+  elif os.path.isfile(src_path):
+    DowngradeFile(src_path, output_dir)
+  else:
+    print(">>> {} not pointing to a valid file or directory".format(src_path))
+    sys.exit(1)
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Downgrade *.mojom files to use the old mojo types.")
+  parser.add_argument(
+      "srcpath", help="path to the file or directory to apply the conversion")
+  parser.add_argument(
+      "--outdir", help="the directory to place the converted file(s) under")
+  args = parser.parse_args()
+
+  DowngradePath(args.srcpath, args.outdir)
+
+
+if __name__ == "__main__":
+  sys.exit(main())