Source/core/scripts/make_runtime_features.py

#!/usr/bin/env python
# Copyright (C) 2013 Google Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#     * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
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# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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import os.path
import sys

from in_file import InFile
import in_generator
import template_expander


class RuntimeFeatureWriter(in_generator.Writer):
    class_name = 'RuntimeEnabledFeatures'

    # FIXME: valid_values and defaults should probably roll into one object.
    valid_values = {
        'status': ['stable', 'experimental', 'test'],
    }
    defaults = {
        'condition' : None,
        'depends_on' : [],
        'custom': False,
        'status': None,
    }

    def __init__(self, in_file_path, enabled_conditions):
        super(RuntimeFeatureWriter, self).__init__(in_file_path, enabled_conditions)
        self._outputs = {(self.class_name + ".h"): self.generate_header,
                         (self.class_name + ".cpp"): self.generate_implementation,
                        }

        self._features = self.in_file.name_dictionaries
        # Make sure the resulting dictionaries have all the keys we expect.
        for feature in self._features:
            feature['first_lowered_name'] = self._lower_first(feature['name'])
            # Most features just check their isFooEnabled bool
            # but some depend on more than one bool.
            enabled_condition = "is%sEnabled" % feature['name']
            for dependant_name in feature['depends_on']:
                enabled_condition += " && is%sEnabled" % dependant_name
            feature['enabled_condition'] = enabled_condition
        self._non_custom_features = filter(lambda feature: not feature['custom'], self._features)

    def _lower_first(self, string):
        lowered = string[0].lower() + string[1:]
        lowered = lowered.replace("cSS", "css")
        lowered = lowered.replace("iME", "ime")
        lowered = lowered.replace("hTML", "html")
        lowered = lowered.replace("wOFF", "woff")
        return lowered

    def _feature_sets(self):
        # Another way to think of the status levels is as "sets of features"
        # which is how we're referring to them in this generator.
        return self.valid_values['status']

    @template_expander.use_jinja(class_name + ".h.tmpl")
    def generate_header(self):
        return {
            'features': self._features,
            'feature_sets': self._feature_sets(),
        }

    @template_expander.use_jinja(class_name + ".cpp.tmpl")
    def generate_implementation(self):
        return {
            'features': self._features,
            'feature_sets': self._feature_sets(),
        }


if __name__ == "__main__":
    in_generator.Maker(RuntimeFeatureWriter).main(sys.argv)