third_party/WebKit/Source/build/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:
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#     * Redistributions of source code must retain the above copyright
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import sys

import json5_generator
import name_utilities
from name_utilities import class_member_name
from name_utilities import lower_first
import template_expander


class RuntimeFeatureWriter(json5_generator.Writer):
    class_name = 'RuntimeEnabledFeatures'

    def __init__(self, json5_file_path):
        super(RuntimeFeatureWriter, self).__init__(json5_file_path)
        self._outputs = {(self.class_name + '.h'): self.generate_header,
                         (self.class_name + '.cpp'): self.generate_implementation,
                        }

        self._features = self.json5_file.name_dictionaries
        # Make sure the resulting dictionaries have all the keys we expect.
        for feature in self._features:
            feature['first_lowered_name'] = lower_first(feature['name'])
            feature['class_member_name'] = class_member_name(feature['name'])
            # Most features just check their isFooEnabled bool
            # but some depend on or are implied by other bools.
            enabled_condition = 'is_%senabled_' % feature['class_member_name']
            assert not feature['implied_by'] or not feature['depends_on'], 'Only one of implied_by and depends_on is allowed'
            for implied_by_name in feature['implied_by']:
                enabled_condition += ' || is_%senabled_' % class_member_name(implied_by_name)
            for dependant_name in feature['depends_on']:
                enabled_condition += ' && is_%senabled_' % class_member_name(dependant_name)
            feature['enabled_condition'] = enabled_condition
        self._standard_features = [feature for feature in self._features if not feature['custom']]
        self._origin_trial_features = [feature for feature in self._features if feature['origin_trial_feature_name']]

    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.json5_file.parameters['status']['valid_values']

    def _template_inputs(self):
        return {
            'features': self._features,
            'feature_sets': self._feature_sets(),
            'input_files': self._input_files,
            'standard_features': self._standard_features,
            'origin_trial_controlled_features': self._origin_trial_features,
        }

    @template_expander.use_jinja('templates/' + class_name + '.h.tmpl')
    def generate_header(self):
        return self._template_inputs()

    @template_expander.use_jinja('templates/' + class_name + '.cpp.tmpl')
    def generate_implementation(self):
        return self._template_inputs()


if __name__ == '__main__':
    json5_generator.Maker(RuntimeFeatureWriter).main()