Add migration concept for shared preferences

app/src/main/java/org/schabi/newpipe/report/UserAction.java

@@ -20,7 +20,8 @@ public enum UserAction {
     DELETE_FROM_HISTORY("delete from history"),
     PLAY_STREAM("Play stream"),
     DOWNLOAD_POSTPROCESSING("download post-processing"),
-    DOWNLOAD_FAILED("download failed");
+    DOWNLOAD_FAILED("download failed"),
+    PREFERENCES_MIGRATION("migration of preferences");
 
 
     private final String message;

app/src/main/java/org/schabi/newpipe/settings/NewPipeSettings.java

@@ -10,6 +10,7 @@ import androidx.preference.PreferenceManager;
 import org.schabi.newpipe.R;
 
 import java.io.File;
+import java.util.Set;
 
 /*
  * Created by k3b on 07.01.2016.
@@ -38,6 +39,22 @@ public final class NewPipeSettings {
     private NewPipeSettings() { }
 
     public static void initSettings(final Context context) {
+        // check if there are entries in the prefs to determine whether this is the first app run
+        Boolean isFirstRun = null;
+        final Set<String> prefsKeys = PreferenceManager.getDefaultSharedPreferences(context)
+                .getAll().keySet();
+        for (final String key: prefsKeys) {
+            // ACRA stores some info in the prefs during app initialization
+            // which happens before this method is called. Therefore ignore ACRA-related keys.
+            if (!key.toLowerCase().startsWith("acra")) {
+                isFirstRun = false;
+                break;
+            }
+        }
+        if (isFirstRun == null) {
+            isFirstRun = true;
+        }
+
         PreferenceManager.setDefaultValues(context, R.xml.appearance_settings, true);
         PreferenceManager.setDefaultValues(context, R.xml.content_settings, true);
         PreferenceManager.setDefaultValues(context, R.xml.download_settings, true);
@@ -48,6 +65,8 @@ public final class NewPipeSettings {
 
         getVideoDownloadFolder(context);
         getAudioDownloadFolder(context);
+
+        SettingMigrations.initMigrations(context, isFirstRun);
     }
 
     private static void getVideoDownloadFolder(final Context context) {

app/src/main/java/org/schabi/newpipe/settings/SettingMigrations.java

@@ -0,0 +1,106 @@
+package org.schabi.newpipe.settings;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.util.Log;
+
+import androidx.preference.PreferenceManager;
+
+import org.schabi.newpipe.R;
+import org.schabi.newpipe.report.ErrorActivity;
+import org.schabi.newpipe.report.ErrorActivity.ErrorInfo;
+import org.schabi.newpipe.report.UserAction;
+
+import static org.schabi.newpipe.MainActivity.DEBUG;
+
+public final class SettingMigrations {
+    private static final String TAG = SettingMigrations.class.toString();
+    /**
+     * Version number for preferences. Must be incremented every time a migration is necessary.
+     */
+    public static final int VERSION = 0;
+    private static SharedPreferences sp;
+
+    /**
+     * List of all implemented migrations.
+     * <p>
+     * <b>Append new migrations to the end of the list</b> to keep it sorted ascending.
+     * If not sorted correctly, migrations which depend on each other, may fail.
+     */
+    private static final Migration[] SETTING_MIGRATIONS = {
+
+    };
+
+
+    public static void initMigrations(final Context context, final boolean isFirstRun) {
+        // setup migrations and check if there is something to do
+        sp = PreferenceManager.getDefaultSharedPreferences(context);
+        final String lastPrefVersionKey = context.getString(R.string.last_used_preferences_version);
+        final int lastPrefVersion = sp.getInt(lastPrefVersionKey, 0);
+
+        // no migration to run, already up to date
+        if (isFirstRun) {
+            sp.edit().putInt(lastPrefVersionKey, VERSION).apply();
+            return;
+        } else if (lastPrefVersion == VERSION) {
+            return;
+        }
+
+        // run migrations
+        int currentVersion = lastPrefVersion;
+        for (final Migration currentMigration : SETTING_MIGRATIONS) {
+            try {
+                if (currentMigration.shouldMigrate(currentVersion)) {
+                    if (DEBUG) {
+                        Log.d(TAG, "Migrating preferences from version "
+                                + currentVersion + " to " + currentMigration.newVersion);
+                    }
+                    currentMigration.migrate(context);
+                    currentVersion = currentMigration.newVersion;
+                }
+            } catch (final Exception e) {
+                // save the version with the last successful migration and report the error
+                sp.edit().putInt(lastPrefVersionKey, currentVersion).apply();
+                final ErrorInfo errorInfo = ErrorInfo.make(
+                        UserAction.PREFERENCES_MIGRATION,
+                        "none",
+                        "Migrating preferences from version " + lastPrefVersion + " to "
+                                + VERSION + ". "
+                                + "Error at " + currentVersion  + " => " + ++currentVersion,
+                        0
+                );
+                ErrorActivity.reportError(context, e, SettingMigrations.class, null, errorInfo);
+                return;
+            }
+        }
+
+        // store the current preferences version
+        sp.edit().putInt(lastPrefVersionKey, currentVersion).apply();
+    }
+
+    private SettingMigrations() { }
+
+    abstract static class Migration {
+        public final int oldVersion;
+        public final int newVersion;
+
+        protected Migration(final int oldVersion, final int newVersion) {
+            this.oldVersion = oldVersion;
+            this.newVersion = newVersion;
+        }
+
+        /**
+         * @param currentVersion current settings version
+         * @return Returns whether this migration should be run.
+         * A migration is necessary if the old version of this migration is lower than or equal to
+         * the current settings version.
+         */
+        private boolean shouldMigrate(final int currentVersion) {
+            return oldVersion >= currentVersion;
+        }
+
+        protected abstract void migrate(Context context);
+
+    }
+
+}

app/src/main/res/values/settings_keys.xml

@@ -1,5 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources translatable="false">
+    <!-- App versioning -->
+    <string name="last_used_version" translatable="false">last_used_version</string>
+    <string name="last_used_preferences_version" translatable="false">last_used_preferences_version</string>
+
     <!-- Service -->
     <string-array name="service_list" translatable="false">
         <item>@string/youtube</item>