The Tor Browser: mobile/android/base/GeckoSharedPrefs.java@b8a032363ba2 (annotated)

mobile/android/base/GeckoSharedPrefs.java@b8a032363ba2 (annotated)

mobile/android/base/GeckoSharedPrefs.java

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 package org.mozilla.gecko;
 import org.mozilla.gecko.mozglue.RobocopTarget;
 import org.mozilla.gecko.util.ThreadUtils;
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.SharedPreferences.Editor;
 import android.os.Build;
 import android.os.StrictMode;
 import android.preference.PreferenceManager;
 import android.util.Log;
 import java.util.Arrays;
 import java.util.EnumSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 /**
  * {@code GeckoSharedPrefs} provides scoped SharedPreferences instances.
  * You should use this API instead of using Context.getSharedPreferences()
  * directly. There are three methods to get scoped SharedPreferences instances:
  *
  * forApp()
  *     Use it for app-wide, cross-profile pref keys.
  * forProfile()
  *     Use it to fetch and store keys for the current profile.
  * forProfileName()
  *     Use it to fetch and store keys from/for a specific profile.
  *
  * {@code GeckoSharedPrefs} has a notion of migrations. Migrations can used to
  * migrate keys from one scope to another. You can trigger a new migration by
  * incrementing PREFS_VERSION and updating migrateIfNecessary() accordingly.
  *
  * Migration history:
  *     1: Move all PreferenceManager keys to app/profile scopes
  */
 @RobocopTarget
 public final class GeckoSharedPrefs {
     private static final String LOGTAG = "GeckoSharedPrefs";
     // Increment it to trigger a new migration
     public static final int PREFS_VERSION = 1;
     // Name for app-scoped prefs
     public static final String APP_PREFS_NAME = "GeckoApp";
     // The prefs key that holds the current migration
     private static final String PREFS_VERSION_KEY = "gecko_shared_prefs_migration";
     // For disabling migration when getting a SharedPreferences instance
     private static final EnumSet<Flags> disableMigrations = EnumSet.of(Flags.DISABLE_MIGRATIONS);
     // Timeout for migration commits to be done (10 seconds)
     private static final int MIGRATION_COMMIT_TIMEOUT_MSEC = 10000;
     // The keys that have to be moved from ProfileManager's default
     // shared prefs to the profile from version 0 to 1.
     private static final String[] PROFILE_MIGRATIONS_0_TO_1 = {
         "home_panels",
         "home_locale"
     };
     // For optimizing the migration check in subsequent get() calls
     private static volatile boolean migrationDone = false;
     public enum Flags {
         DISABLE_MIGRATIONS
     }
     // Used when fetching profile-scoped prefs.
     private static final String PROFILE_PREFS_NAME_PREFIX = "GeckoProfile-";
     public static SharedPreferences forApp(Context context) {
         return forApp(context, EnumSet.noneOf(Flags.class));
     }
     /**
      * Returns an app-scoped SharedPreferences instance. You can disable
      * migrations by using the DISABLE_MIGRATIONS flag.
      */
     public static SharedPreferences forApp(Context context, EnumSet<Flags> flags) {
         if (flags != null && !flags.contains(Flags.DISABLE_MIGRATIONS)) {
             migrateIfNecessary(context);
         }
         return context.getSharedPreferences(APP_PREFS_NAME, 0);
     }
     public static SharedPreferences forProfile(Context context) {
         return forProfile(context, EnumSet.noneOf(Flags.class));
     }
     /**
      * Returns a SharedPreferences instance scoped to the current profile
      * in the app. You can disable migrations by using the DISABLE_MIGRATIONS
      * flag.
      */
     public static SharedPreferences forProfile(Context context, EnumSet<Flags> flags) {
         String profileName = GeckoProfile.get(context).getName();
         if (profileName == null) {
             throw new IllegalStateException("Could not get current profile name");
         }
         return forProfileName(context, profileName, flags);
     }
     public static SharedPreferences forProfileName(Context context, String profileName) {
         return forProfileName(context, profileName, EnumSet.noneOf(Flags.class));
     }
     /**
      * Returns an SharedPreferences instance scoped to the given profile name.
      * You can disable migrations by using the DISABLE_MIGRATION flag.
      */
     public static SharedPreferences forProfileName(Context context, String profileName,
             EnumSet<Flags> flags) {
         if (flags != null && !flags.contains(Flags.DISABLE_MIGRATIONS)) {
             migrateIfNecessary(context);
         }
         final String prefsName = PROFILE_PREFS_NAME_PREFIX + profileName;
         return context.getSharedPreferences(prefsName, 0);
     }
     /**
      * Returns the current version of the prefs.
      */
     public static int getVersion(Context context) {
         return forApp(context, disableMigrations).getInt(PREFS_VERSION_KEY, 0);
     }
     /**
      * Resets migration flag. Should only be used in tests.
      */
     public static synchronized void reset() {
         migrationDone = false;
     }
     /**
      * Performs all prefs migrations in the background thread to avoid StrictMode
      * exceptions from reading/writing in the UI thread. This method will block
      * the current thread until the migration is finished.
      */
     private static synchronized void migrateIfNecessary(final Context context) {
         if (migrationDone) {
             return;
         }
         // We deliberatly perform the migration in the current thread (which
         // is likely the UI thread) as this is actually cheaper than enforcing a
         // context switch to another thread (see bug 940575).
         if (Build.VERSION.SDK_INT < 9) {
             performMigration(context);
         } else {
             // Avoid strict mode warnings.
             final StrictMode.ThreadPolicy savedPolicy = StrictMode.allowThreadDiskReads();
             StrictMode.allowThreadDiskWrites();
             try {
                 performMigration(context);
             } finally {
                 StrictMode.setThreadPolicy(savedPolicy);
             }
         }
         migrationDone = true;
     }
     private static void performMigration(Context context) {
         final SharedPreferences appPrefs = forApp(context, disableMigrations);
         final int currentVersion = appPrefs.getInt(PREFS_VERSION_KEY, 0);
         Log.d(LOGTAG, "Current version = " + currentVersion + ", prefs version = " + PREFS_VERSION);
         if (currentVersion == PREFS_VERSION) {
             return;
         }
         Log.d(LOGTAG, "Performing migration");
         final Editor appEditor = appPrefs.edit();
         // The migration always moves prefs to the default profile, not
         // the current one. We might have to revisit this if we ever support
         // multiple profiles.
         final String defaultProfileName;
         try {
             defaultProfileName = GeckoProfile.getDefaultProfileName(context);
         } catch (Exception e) {
             throw new IllegalStateException("Failed to get default profile name for migration");
         }
         final Editor profileEditor = forProfileName(context, defaultProfileName, disableMigrations).edit();
         List<String> profileKeys;
         Editor pmEditor = null;
         for (int v = currentVersion + 1; v <= PREFS_VERSION; v++) {
             Log.d(LOGTAG, "Migrating to version = " + v);
             switch (v) {
                 case 1:
                     profileKeys = Arrays.asList(PROFILE_MIGRATIONS_0_TO_1);
                     pmEditor = migrateFromPreferenceManager(context, appEditor, profileEditor, profileKeys);
                     break;
             }
         }
         // Update prefs version accordingly.
         appEditor.putInt(PREFS_VERSION_KEY, PREFS_VERSION);
         appEditor.commit();
         profileEditor.commit();
         if (pmEditor != null) {
             pmEditor.commit();
         }
         Log.d(LOGTAG, "All keys have been migrated");
     }
     /**
      * Moves all preferences stored in PreferenceManager's default prefs
      * to either app or profile scopes. The profile-scoped keys are defined
      * in given profileKeys list, all other keys are moved to the app scope.
      */
     public static Editor migrateFromPreferenceManager(Context context, Editor appEditor,
             Editor profileEditor, List<String> profileKeys) {
         Log.d(LOGTAG, "Migrating from PreferenceManager");
         final SharedPreferences pmPrefs =
                 PreferenceManager.getDefaultSharedPreferences(context);
         for (Map.Entry<String, ?> entry : pmPrefs.getAll().entrySet()) {
             final String key = entry.getKey();
             final Editor to;
             if (profileKeys.contains(key)) {
                 to = profileEditor;
             } else {
                 to = appEditor;
             }
             putEntry(to, key, entry.getValue());
         }
         // Clear PreferenceManager's prefs once we're done
         // and return the Editor to be committed.
         return pmPrefs.edit().clear();
     }
     @SuppressWarnings("unchecked")
     private static void putEntry(Editor to, String key, Object value) {
         Log.d(LOGTAG, "Migrating key = " + key + " with value = " + value);
         if (value instanceof String) {
             to.putString(key, (String) value);
         } else if (value instanceof Boolean) {
             to.putBoolean(key, (Boolean) value);
         } else if (value instanceof Long) {
             to.putLong(key, (Long) value);
         } else if (value instanceof Float) {
             to.putFloat(key, (Float) value);
         } else if (value instanceof Integer) {
             to.putInt(key, (Integer) value);
         } else {
             throw new IllegalStateException("Unrecognized value type for key: " + key);
         }
     }
 }

The Tor Browser / annotate

mobile/android/base/GeckoSharedPrefs.java@b8a032363ba2 (annotated)

mobile/android/base/GeckoSharedPrefs.java