Introduce legacy settings restore whitelists

On rare occasion we have settings keys that we no longer want to
back up, but which we *do* want to process at restore time for
support of legacy backup datasets.  We now have a little bit of
machinery for the idea of restore-only key whitelists, paralling
the SETTINGS_TO_BACKUP dual-purpose whitelists.

Bug 62263757
Test: manual

Change-Id: Ic32ad679bc4b5028dd52dc71e9ab5836a76307c4

diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 172ba89..3c4f946 100755 (executable)
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -3973,6 +3973,15 @@ public final class Settings {
         };
 
         /**
+         * Keys we no longer back up under the current schema, but want to continue to
+         * process when restoring historical backup datasets.
+         *
+         * @hide
+         */
+        public static final String[] LEGACY_RESTORE_SETTINGS = {
+        };
+
+        /**
          * These are all public system settings
          *
          * @hide
@@ -7085,6 +7094,10 @@ public final class Settings {
             NOTIFICATION_BADGING
         };
 
+        /** @hide */
+        public static final String[] LEGACY_RESTORE_SETTINGS = {
+        };
+
         /**
          * These entries are considered common between the personal and the managed profile,
          * since the managed profile doesn't get to change them.
@@ -10088,6 +10101,10 @@ public final class Settings {
             BLUETOOTH_ON
         };
 
+        /** @hide */
+        public static final String[] LEGACY_RESTORE_SETTINGS = {
+        };
+
         private static final ContentProviderHolder sProviderHolder =
                 new ContentProviderHolder(CONTENT_URI);
 

diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
index 533c52b..96f51c1 100644 (file)
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsBackupAgent.java
@@ -16,6 +16,7 @@
 
 package com.android.providers.settings;
 
+import android.annotation.Nullable;
 import android.annotation.UserIdInt;
 import android.app.backup.BackupAgentHelper;
 import android.app.backup.BackupDataInput;
@@ -30,7 +31,6 @@ import android.net.NetworkPolicyManager;
 import android.net.Uri;
 import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiManager;
-import android.os.Handler;
 import android.os.ParcelFileDescriptor;
 import android.os.UserHandle;
 import android.provider.Settings;
@@ -590,14 +590,18 @@ public class SettingsBackupAgent extends BackupAgentHelper {
             Log.i(TAG, "restoreSettings: " + contentUri);
         }
 
-        // Figure out the white list and redirects to the global table.
+        // Figure out the white list and redirects to the global table.  We restore anything
+        // in either the backup whitelist or the legacy-restore whitelist for this table.
         final String[] whitelist;
         if (contentUri.equals(Settings.Secure.CONTENT_URI)) {
-            whitelist = Settings.Secure.SETTINGS_TO_BACKUP;
+            whitelist = concat(Settings.Secure.SETTINGS_TO_BACKUP,
+                    Settings.Secure.LEGACY_RESTORE_SETTINGS);
         } else if (contentUri.equals(Settings.System.CONTENT_URI)) {
-            whitelist = Settings.System.SETTINGS_TO_BACKUP;
+            whitelist = concat(Settings.System.SETTINGS_TO_BACKUP,
+                    Settings.System.LEGACY_RESTORE_SETTINGS);
         } else if (contentUri.equals(Settings.Global.CONTENT_URI)) {
-            whitelist = Settings.Global.SETTINGS_TO_BACKUP;
+            whitelist = concat(Settings.Global.SETTINGS_TO_BACKUP,
+                    Settings.Global.LEGACY_RESTORE_SETTINGS);
         } else {
             throw new IllegalArgumentException("Unknown URI: " + contentUri);
         }
@@ -648,6 +652,18 @@ public class SettingsBackupAgent extends BackupAgentHelper {
         }
     }
 
+    private final String[] concat(String[] first, @Nullable String[] second) {
+        if (second == null || second.length == 0) {
+            return first;
+        }
+        final int firstLen = first.length;
+        final int secondLen = second.length;
+        String[] both = new String[firstLen + secondLen];
+        System.arraycopy(first, 0, both, 0, firstLen);
+        System.arraycopy(second, 0, both, firstLen, secondLen);
+        return both;
+    }
+
     /**
      * Restores the owner info enabled and other settings in LockSettings.
      *