Generate shim headers for libpng

tools/generate_shim_headers/generate_shim_headers.py

Index: tools/generate_shim_headers/generate_shim_headers.py
diff --git a/tools/generate_shim_headers/generate_shim_headers.py b/tools/generate_shim_headers/generate_shim_headers.py
new file mode 100755
index 0000000000000000000000000000000000000000..068a2ac60c870ab0db1d47e06d34bbb93f3e68fa
--- /dev/null
+++ b/tools/generate_shim_headers/generate_shim_headers.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python
+# Copyright (c) 2012 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.
+
+"""
+Generates shim headers that mirror the directory structure of bundled headers,
+but just forward to the system ones.
+
+This allows seamless compilation against system headers with no changes
+to our source code.
+"""
+
+
+import optparse
+import os.path
+import sys
+
+
+SHIM_TEMPLATE = """
+#if defined(OFFICIAL_BUILD)
+#error shim headers must not be used in official builds!
+#endif
+
+#include <%s>
+"""
+
+
+def GeneratorMain(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('--headers-root')
+  parser.add_option('--output-directory')
+  parser.add_option('--outputs', action='store_true')
+  parser.add_option('--generate', action='store_true')
+
+  options, args = parser.parse_args(argv)
+
+  if not options.headers_root:
+    parser.error('Missing --headers-root parameter.')
+  if not options.output_directory:
+    parser.error('Missing --output-directory parameter.')
+  if not args:
+    parser.error('Missing arguments - header file names.')
+
+  source_tree_root = os.path.abspath(
+    os.path.join(os.path.dirname(__file__), '..', '..'))
+
+  target_directory = os.path.join(
+    options.output_directory,
+    os.path.relpath(options.headers_root, source_tree_root))
+  if options.generate and not os.path.exists(target_directory):
+    os.makedirs(target_directory)
+  for header_filename in args:
+    if options.outputs:
+      yield os.path.join(target_directory, header_filename)
+    if options.generate:
+      with open(os.path.join(target_directory, header_filename), 'w') as f:
+        f.write(SHIM_TEMPLATE % header_filename)
+
+
+def DoMain(argv):
+  return '\n'.join(GeneratorMain(argv))
+
+
+if __name__ == '__main__':
+  DoMain(sys.argv[1:])