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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.util;
     18 
     19 import android.content.Context;
     20 import android.os.SystemProperties;
     21 import android.provider.Settings;
     22 import android.text.TextUtils;
     23 
     24 import java.util.HashMap;
     25 import java.util.Map;
     26 
     27 /**
     28  * Util class to get feature flag information.
     29  *
     30  * @hide
     31  */
     32 public class FeatureFlagUtils {
     33 
     34     public static final String FFLAG_PREFIX = "sys.fflag.";
     35     public static final String FFLAG_OVERRIDE_PREFIX = FFLAG_PREFIX + "override.";
     36 
     37     private static final Map<String, String> DEFAULT_FLAGS;
     38     static {
     39         DEFAULT_FLAGS = new HashMap<>();
     40         DEFAULT_FLAGS.put("settings_battery_display_app_list", "false");
     41         DEFAULT_FLAGS.put("settings_zone_picker_v2", "true");
     42         DEFAULT_FLAGS.put("settings_about_phone_v2", "true");
     43         DEFAULT_FLAGS.put("settings_bluetooth_while_driving", "false");
     44         DEFAULT_FLAGS.put("settings_data_usage_v2", "true");
     45         DEFAULT_FLAGS.put("settings_audio_switcher", "true");
     46         DEFAULT_FLAGS.put("settings_systemui_theme", "true");
     47     }
     48 
     49     /**
     50      * Whether or not a flag is enabled.
     51      *
     52      * @param feature the flag name
     53      * @return true if the flag is enabled (either by default in system, or override by user)
     54      */
     55     public static boolean isEnabled(Context context, String feature) {
     56         // Override precedence:
     57         // Settings.Global -> sys.fflag.override.* -> static list
     58 
     59         // Step 1: check if feature flag is set in Settings.Global.
     60         String value;
     61         if (context != null) {
     62             value = Settings.Global.getString(context.getContentResolver(), feature);
     63             if (!TextUtils.isEmpty(value)) {
     64                 return Boolean.parseBoolean(value);
     65             }
     66         }
     67 
     68         // Step 2: check if feature flag has any override. Flag name: sys.fflag.override.<feature>
     69         value = SystemProperties.get(FFLAG_OVERRIDE_PREFIX + feature);
     70         if (!TextUtils.isEmpty(value)) {
     71             return Boolean.parseBoolean(value);
     72         }
     73         // Step 3: check if feature flag has any default value.
     74         value = getAllFeatureFlags().get(feature);
     75         return Boolean.parseBoolean(value);
     76     }
     77 
     78     /**
     79      * Override feature flag to new state.
     80      */
     81     public static void setEnabled(Context context, String feature, boolean enabled) {
     82         SystemProperties.set(FFLAG_OVERRIDE_PREFIX + feature, enabled ? "true" : "false");
     83     }
     84 
     85     /**
     86      * Returns all feature flags in their raw form.
     87      */
     88     public static Map<String, String> getAllFeatureFlags() {
     89         return DEFAULT_FLAGS;
     90     }
     91 }
     92