Implement --ozone-platform flag to select OzonePlatform implementation at runtime

ui/ozone/generate_ozone_platform_list.py

Index: ui/ozone/generate_ozone_platform_list.py
diff --git a/ui/ozone/generate_ozone_platform_list.py b/ui/ozone/generate_ozone_platform_list.py
new file mode 100755
index 0000000000000000000000000000000000000000..a73ead719a04453869ccef39782fce6b735b9299
--- /dev/null
+++ b/ui/ozone/generate_ozone_platform_list.py
@@ -0,0 +1,101 @@
+#!/usr/bin/env python
+# Copyright (c) 2013 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.
+
+"""Code generator for Ozone platform list.
+
+This script takes as arguments a list of platform names and generates a C++
+source file containing a list of those platforms. Each list entry contains the
+name and a function pointer to the initializer for that platform.
+
+Example Output: ./generate_ozone_platform_list.py --default wayland dri wayland
+
+  #include "ui/ozone/ozone_platform_list.h"
+
+  namespace ui {
+
+  OzonePlatform* CreateOzonePlatformDri();
+  OzonePlatform* CreateOzonePlatformWayland();
+
+  const OzonePlatformListEntry kOzonePlatforms[] = {
+    { "wayland", &CreateOzonePlatformWayland },
+    { "dri", &CreateOzonePlatformDri },
+  };
+
+  const int kOzonePlatformCount = 2;
+
+  }  // namespace ui
+"""
+
+import optparse
+import os
+import collections
+import re
+import sys
+import string
+
+
+def GetConstructorName(name):
+  """Determine name of static constructor function from platform name.
+
+  We just capitalize the platform name and prepend "CreateOzonePlatform".
+  """
+
+  return 'CreateOzonePlatform' + string.capitalize(name)
+
+
+def GeneratePlatformList(out, platforms):
+  """Generate static array containing a list of ozone platforms."""
+
+  out.write('#include "ui/ozone/ozone_platform_list.h"\n')
+  out.write('\n')
+
+  out.write('namespace ui {\n')
+  out.write('\n')
+
+  # Prototypes for platform initializers.
+  for platform in platforms:
+    out.write('OzonePlatform* %s();\n' % GetConstructorName(platform))
+  out.write('\n')
+
+  # List of platform names and initializers.
+  out.write('const OzonePlatformListEntry kOzonePlatforms[] = {\n')
+  for platform in platforms:
+    out.write('  { "%s", &%s },\n' % (platform, GetConstructorName(platform)))
+  out.write('};\n')
+  out.write('\n')
+
+  out.write('const int kOzonePlatformCount = %d;\n' % len(platforms))
+  out.write('\n')
+
+  out.write('}  // namespace ui\n')
+
+
+def main(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('--output_file')
+  parser.add_option('--default')
+  options, platforms = parser.parse_args(argv)
+
+  # Write to standard output or file specified by --output_file.
+  out = sys.stdout
+  if options.output_file:
+    out = open(options.output_file, 'wb')
+
+  # Reorder the platforms when --default is specified.
+  # The default platform must appear first in the platform list.
+  if options.default and options.default in platforms:
+    platforms.remove(options.default)
+    platforms.insert(0, options.default)
+
+  GeneratePlatformList(out, platforms)
+
+  if options.output_file:
+    out.close()
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))