| # Copyright 2019 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. |
| |
| import json5 |
| |
| |
| class RuntimeEnabledFeatures(object): |
| """Represents a set of definitions of runtime enabled features.""" |
| |
| _REQUIRE_INIT_MESSAGE = ( |
| "RuntimeEnabledFeatures.init must be called in advance.") |
| _is_initialized = False |
| |
| @classmethod |
| def init(cls, filepaths): |
| """ |
| Args: |
| filepaths: Paths to the definition files of runtime-enabled features |
| ("runtime_enabled_features.json5"). |
| """ |
| assert not cls._is_initialized |
| assert isinstance(filepaths, list) |
| assert all(isinstance(filepath, str) for filepath in filepaths) |
| |
| cls._features = {} |
| |
| for filepath in filepaths: |
| with open(filepath) as file_obj: |
| datastore = json5.load(file_obj) |
| |
| for entry in datastore["data"]: |
| assert entry["name"] not in cls._features |
| cls._features[entry["name"]] = entry |
| |
| cls._is_initialized = True |
| |
| @classmethod |
| def is_context_dependent(cls, feature_name): |
| """Returns True if the feature may be enabled per-context.""" |
| assert cls._is_initialized, cls._REQUIRE_INIT_MESSAGE |
| assert isinstance(feature_name, str) |
| assert feature_name in cls._features, ( |
| "Unknown runtime-enabled feature: {}".format(feature_name)) |
| return cls._features[feature_name].get( |
| "origin_trial_feature_name") is not None |
