Perform preference schema upgrades at startup (#3186)

* Perform preference schema upgrades at startup

Over time it can be desirable to change how preferences are interpreted.

Preferences might be removed, or renamed. Or the default value for a
preference might be changed.

When this happens it's important that users upgrading from one version to
the next (or jumping from one version to several versions ahead) get a
consistent experience. In particular:

- Preferences that no longer exist should be deleted
- Preferences that have been renamed should have the old preference values
  copied over
- If the user used the default value for the preference, and the default has
  changed, the previous default value should be explicitly set as their
  value for the preference

To support this, store a SCHEMA_VERSION as a preference. This is not exposed
to the user, and corresponds to the app's VERSION_CODE.

If the version code does not match the schema version then this is a newer
version of the app with older preferences that may need to be changed.

Those changes will be implemented in `upgradeSharedPreferences`.

* Translated using Weblate (Hungarian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Gera, Zoltan <gerazo@manioka.hu>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/hu/
Translation: Tusky/Tusky

* Translated using Weblate (Chinese (Simplified))

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Eric <alchemillatruth@purelymail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/zh_Hans/
Translation: Tusky/Tusky

* Translated using Weblate (Ukrainian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Ihor Hordiichuk <igor_ck@outlook.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/uk/
Translation: Tusky/Tusky

* Translated using Weblate (Vietnamese)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Hồ Nhất Duy <mastoduy@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/vi/
Translation: Tusky/Tusky

* Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Mikalai <mikalai.hryb@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/be/
Translation: Tusky/Tusky

* Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Andrej Zabavin <andre.zabavin@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/be/
Translation: Tusky/Tusky

* Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Mikalai <mikalai.hryb@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/be/
Translation: Tusky/Tusky

* Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: xzFantom <xzfantom@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/be/
Translation: Tusky/Tusky

* Translated using Weblate (Japanese)

Currently translated at 91.3% (504 of 552 strings)

Co-authored-by: TAKAHASHI Shuuji <shuuji3@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/ja/
Translation: Tusky/Tusky

* Translated using Weblate (Icelandic)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Sveinn í Felli <sv1@fellsnet.is>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/is/
Translation: Tusky/Tusky

* Translated using Weblate (Belarusian)

Currently translated at 100.0% (552 of 552 strings)

Co-authored-by: Mikalai <mikalai.hryb@gmail.com>
Translate-URL: https://weblate.tusky.app/projects/tusky/tusky/be/
Translation: Tusky/Tusky

* Lint

---------

Co-authored-by: Gera, Zoltan <gerazo@manioka.hu>
Co-authored-by: Eric <alchemillatruth@purelymail.com>
Co-authored-by: Ihor Hordiichuk <igor_ck@outlook.com>
Co-authored-by: Hồ Nhất Duy <mastoduy@gmail.com>
Co-authored-by: Mikalai <mikalai.hryb@gmail.com>
Co-authored-by: Andrej Zabavin <andre.zabavin@gmail.com>
Co-authored-by: xzFantom <xzfantom@gmail.com>
Co-authored-by: TAKAHASHI Shuuji <shuuji3@gmail.com>
Co-authored-by: Sveinn í Felli <sv1@fellsnet.is>

app/src/main/java/com/keylesspalace/tusky/TuskyApplication.kt

@@ -16,12 +16,13 @@
 package com.keylesspalace.tusky
 
 import android.app.Application
+import android.content.SharedPreferences
 import android.util.Log
-import androidx.preference.PreferenceManager
 import androidx.work.WorkManager
 import autodispose2.AutoDisposePlugins
 import com.keylesspalace.tusky.components.notifications.NotificationWorkerFactory
 import com.keylesspalace.tusky.di.AppInjector
+import com.keylesspalace.tusky.settings.PrefKeys
 import com.keylesspalace.tusky.util.APP_THEME_DEFAULT
 import com.keylesspalace.tusky.util.LocaleManager
 import com.keylesspalace.tusky.util.setAppNightMode
@@ -36,7 +37,6 @@ import java.security.Security
 import javax.inject.Inject
 
 class TuskyApplication : Application(), HasAndroidInjector {
-
     @Inject
     lateinit var androidInjector: DispatchingAndroidInjector<Any>
 
@@ -46,6 +46,9 @@ class TuskyApplication : Application(), HasAndroidInjector {
     @Inject
     lateinit var localeManager: LocaleManager
 
+    @Inject
+    lateinit var sharedPreferences: SharedPreferences
+
     override fun onCreate() {
         // Uncomment me to get StrictMode violation logs
 //        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
@@ -65,7 +68,12 @@ class TuskyApplication : Application(), HasAndroidInjector {
 
         AppInjector.init(this)
 
-        val preferences = PreferenceManager.getDefaultSharedPreferences(this)
+        // Migrate shared preference keys and defaults from version to version. The last
+        // version that did not have a SCHEMA_VERSION was 97, so that's the default.
+        val oldVersion = sharedPreferences.getInt(PrefKeys.SCHEMA_VERSION, 97)
+        if (oldVersion != BuildConfig.VERSION_CODE) {
+            upgradeSharedPreferences(oldVersion, BuildConfig.VERSION_CODE)
+        }
 
         // In this case, we want to have the emoji preferences merged with the other ones
         // Copied from PreferenceManager.getDefaultSharedPreferenceName
@@ -73,7 +81,7 @@ class TuskyApplication : Application(), HasAndroidInjector {
         EmojiPackHelper.init(this, DefaultEmojiPackList.get(this), allowPackImports = false)
 
         // init night mode
-        val theme = preferences.getString("appTheme", APP_THEME_DEFAULT)
+        val theme = sharedPreferences.getString("appTheme", APP_THEME_DEFAULT)
         setAppNightMode(theme)
 
         localeManager.setLocale()
@@ -91,4 +99,18 @@ class TuskyApplication : Application(), HasAndroidInjector {
     }
 
     override fun androidInjector() = androidInjector
+
+    private fun upgradeSharedPreferences(oldVersion: Int, newVersion: Int) {
+        Log.d(TAG, "Upgrading shared preferences: $oldVersion -> $newVersion")
+        val editor = sharedPreferences.edit()
+
+        // Future upgrade code goes here
+
+        editor.putInt(PrefKeys.SCHEMA_VERSION, newVersion)
+        editor.apply()
+    }
+
+    companion object {
+        private const val TAG = "TuskyApplication"
+    }
 }

app/src/main/java/com/keylesspalace/tusky/settings/SettingsConstants.kt

@@ -16,6 +16,7 @@ object PrefKeys {
     // Note: not all of these keys are actually used as SharedPreferences keys but we must give
     // each preference a key for it to work.
 
+    const val SCHEMA_VERSION: String = "schema_version"
     const val APP_THEME = "appTheme"
     const val EMOJI = "selected_emoji_font"
     const val FAB_HIDE = "fabHide"