Use dependency injection with Koin

app/build.gradle

@@ -109,6 +109,7 @@ dependencies {
 
     implementation 'commons-io:commons-io:2.6'
     implementation 'io.github.novacrypto:BIP39:2019.01.27'
+    implementation 'org.koin:koin-androidx-viewmodel:2.0.1'
 
     implementation 'androidx.core:core-ktx:1.1.0'
     implementation 'androidx.preference:preference-ktx:1.1.0'

app/src/androidTest/java/com/stevesoltys/seedvault/DocumentsStorageTest.kt

@@ -3,23 +3,26 @@ package com.stevesoltys.seedvault
 import androidx.documentfile.provider.DocumentFile
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.runner.AndroidJUnit4
-import com.stevesoltys.seedvault.transport.backup.plugins.DocumentsStorage
+import com.stevesoltys.seedvault.settings.SettingsManager
-import com.stevesoltys.seedvault.transport.backup.plugins.createOrGetFile
+import com.stevesoltys.seedvault.plugins.saf.DocumentsStorage
+import com.stevesoltys.seedvault.plugins.saf.createOrGetFile
 import org.junit.After
 import org.junit.Assert.assertArrayEquals
 import org.junit.Assert.assertNotNull
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.koin.core.KoinComponent
+import org.koin.core.inject
 import kotlin.random.Random
 
 private const val filename = "test-file"
 
 @RunWith(AndroidJUnit4::class)
-class DocumentsStorageTest {
+class DocumentsStorageTest : KoinComponent {
 
     private val context = InstrumentationRegistry.getInstrumentation().targetContext
-    private val settingsManager = (context.applicationContext as Backup).settingsManager
+    private val settingsManager by inject<SettingsManager>()
     private val storage = DocumentsStorage(context, settingsManager)
 
     private lateinit var file: DocumentFile

app/src/main/AndroidManifest.xml

@@ -25,7 +25,7 @@
         tools:ignore="ProtectedPermissions" />
 
     <application
-        android:name=".Backup"
+        android:name=".App"
         android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"

app/src/main/java/com/stevesoltys/seedvault/App.kt

@@ -0,0 +1,66 @@
+package com.stevesoltys.seedvault
+
+import android.app.Application
+import android.app.backup.BackupManager.PACKAGE_MANAGER_SENTINEL
+import android.app.backup.IBackupManager
+import android.content.Context.BACKUP_SERVICE
+import android.os.Build
+import android.os.ServiceManager.getService
+import com.stevesoltys.seedvault.crypto.cryptoModule
+import com.stevesoltys.seedvault.header.headerModule
+import com.stevesoltys.seedvault.metadata.metadataModule
+import com.stevesoltys.seedvault.restore.RestoreViewModel
+import com.stevesoltys.seedvault.settings.SettingsManager
+import com.stevesoltys.seedvault.settings.SettingsViewModel
+import com.stevesoltys.seedvault.transport.backup.backupModule
+import com.stevesoltys.seedvault.plugins.saf.documentsProviderModule
+import com.stevesoltys.seedvault.transport.restore.restoreModule
+import com.stevesoltys.seedvault.ui.recoverycode.RecoveryCodeViewModel
+import com.stevesoltys.seedvault.ui.storage.BackupStorageViewModel
+import com.stevesoltys.seedvault.ui.storage.RestoreStorageViewModel
+import org.koin.android.ext.koin.androidContext
+import org.koin.android.ext.koin.androidLogger
+import org.koin.androidx.viewmodel.dsl.viewModel
+import org.koin.core.context.startKoin
+import org.koin.dsl.module
+
+/**
+ * @author Steve Soltys
+ * @author Torsten Grote
+ */
+class App : Application() {
+
+    private val appModule = module {
+        single { SettingsManager(this@App) }
+        single { BackupNotificationManager(this@App) }
+        factory<IBackupManager> { IBackupManager.Stub.asInterface(getService(BACKUP_SERVICE)) }
+
+        viewModel { SettingsViewModel(this@App, get(), get()) }
+        viewModel { RecoveryCodeViewModel(this@App, get()) }
+        viewModel { BackupStorageViewModel(this@App, get(), get()) }
+        viewModel { RestoreStorageViewModel(this@App, get(), get()) }
+        viewModel { RestoreViewModel(this@App, get(), get(), get()) }
+    }
+
+    override fun onCreate() {
+        super.onCreate()
+        startKoin {
+            androidLogger()
+            androidContext(this@App)
+            modules(listOf(
+                    cryptoModule,
+                    headerModule,
+                    metadataModule,
+                    documentsProviderModule,  // storage plugin
+                    backupModule,
+                    restoreModule,
+                    appModule
+            ))
+        }
+    }
+
+}
+
+const val MAGIC_PACKAGE_MANAGER = PACKAGE_MANAGER_SENTINEL
+
+fun isDebugBuild() = Build.TYPE == "userdebug"

app/src/main/java/com/stevesoltys/seedvault/Backup.kt

@@ -1,39 +0,0 @@
-package com.stevesoltys.seedvault
-
-import android.app.Application
-import android.app.backup.BackupManager.PACKAGE_MANAGER_SENTINEL
-import android.app.backup.IBackupManager
-import android.content.Context.BACKUP_SERVICE
-import android.os.Build
-import android.os.ServiceManager.getService
-import com.stevesoltys.seedvault.crypto.KeyManager
-import com.stevesoltys.seedvault.crypto.KeyManagerImpl
-import com.stevesoltys.seedvault.settings.SettingsManager
-
-/**
- * @author Steve Soltys
- * @author Torsten Grote
- */
-class Backup : Application() {
-
-    companion object {
-        val backupManager: IBackupManager by lazy {
-            IBackupManager.Stub.asInterface(getService(BACKUP_SERVICE))
-        }
-        val keyManager: KeyManager by lazy {
-            KeyManagerImpl()
-        }
-    }
-
-    val settingsManager by lazy {
-        SettingsManager(this)
-    }
-    val notificationManager by lazy {
-        BackupNotificationManager(this)
-    }
-
-}
-
-const val MAGIC_PACKAGE_MANAGER = PACKAGE_MANAGER_SENTINEL
-
-fun isDebugBuild() = Build.TYPE == "userdebug"

app/src/main/java/com/stevesoltys/seedvault/NotificationBackupObserver.kt

@@ -7,13 +7,15 @@ import android.content.pm.PackageManager
 import android.util.Log
 import android.util.Log.INFO
 import android.util.Log.isLoggable
+import org.koin.core.KoinComponent
+import org.koin.core.inject
 
 private val TAG = NotificationBackupObserver::class.java.simpleName
 
-class NotificationBackupObserver(context: Context, private val userInitiated: Boolean) : IBackupObserver.Stub() {
+class NotificationBackupObserver(context: Context, private val userInitiated: Boolean) : IBackupObserver.Stub(), KoinComponent {
 
     private val pm = context.packageManager
-    private val nm = (context.applicationContext as Backup).notificationManager
+    private val nm: BackupNotificationManager by inject()
 
     /**
      * This method could be called several times for packages with full data backup.

app/src/main/java/com/stevesoltys/seedvault/UsbIntentReceiver.kt

@@ -12,19 +12,23 @@ import android.os.Handler
 import android.provider.DocumentsContract
 import android.util.Log
 import com.stevesoltys.seedvault.settings.FlashDrive
+import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.transport.requestBackup
 import com.stevesoltys.seedvault.ui.storage.AUTHORITY_STORAGE
+import org.koin.core.KoinComponent
+import org.koin.core.inject
 import java.util.*
 import java.util.concurrent.TimeUnit.HOURS
 
 private val TAG = UsbIntentReceiver::class.java.simpleName
 
-class UsbIntentReceiver : UsbMonitor() {
+class UsbIntentReceiver : UsbMonitor(), KoinComponent {
+
+    private val settingsManager by inject<SettingsManager>()
 
     override fun shouldMonitorStatus(context: Context, action: String, device: UsbDevice): Boolean {
         if (action != ACTION_USB_DEVICE_ATTACHED) return false
         Log.d(TAG, "Checking if this is the current backup drive.")
-        val settingsManager = (context.applicationContext as Backup).settingsManager
         val savedFlashDrive = settingsManager.getFlashDrive() ?: return false
         val attachedFlashDrive = FlashDrive.from(device)
         return if (savedFlashDrive == attachedFlashDrive) {

app/src/main/java/com/stevesoltys/seedvault/crypto/CipherFactory.kt

@@ -13,7 +13,7 @@ interface CipherFactory {
     fun createDecryptionCipher(iv: ByteArray): Cipher
 }
 
-class CipherFactoryImpl(private val keyManager: KeyManager) : CipherFactory {
+internal class CipherFactoryImpl(private val keyManager: KeyManager) : CipherFactory {
 
     override fun createEncryptionCipher(): Cipher {
         return Cipher.getInstance(CIPHER_TRANSFORMATION).apply {

app/src/main/java/com/stevesoltys/seedvault/crypto/Crypto.kt

@@ -71,7 +71,7 @@ interface Crypto {
     fun decryptSegment(inputStream: InputStream): ByteArray
 }
 
-class CryptoImpl(
+internal class CryptoImpl(
         private val cipherFactory: CipherFactory,
         private val headerWriter: HeaderWriter,
         private val headerReader: HeaderReader) : Crypto {

app/src/main/java/com/stevesoltys/seedvault/crypto/CryptoModule.kt

@@ -0,0 +1,9 @@
+package com.stevesoltys.seedvault.crypto
+
+import org.koin.dsl.module
+
+val cryptoModule = module {
+    factory<CipherFactory> { CipherFactoryImpl(get()) }
+    single<KeyManager> { KeyManagerImpl() }
+    single<Crypto> { CryptoImpl(get(), get(), get()) }
+}

app/src/main/java/com/stevesoltys/seedvault/crypto/KeyManager.kt

@@ -35,7 +35,7 @@ interface KeyManager {
     fun getBackupKey(): SecretKey
 }
 
-class KeyManagerImpl : KeyManager {
+internal class KeyManagerImpl : KeyManager {
 
     private val keyStore by lazy {
         KeyStore.getInstance(ANDROID_KEY_STORE).apply {

app/src/main/java/com/stevesoltys/seedvault/header/HeaderModule.kt

@@ -0,0 +1,8 @@
+package com.stevesoltys.seedvault.header
+
+import org.koin.dsl.module
+
+val headerModule = module {
+    single<HeaderWriter> { HeaderWriterImpl() }
+    single<HeaderReader> { HeaderReaderImpl() }
+}

app/src/main/java/com/stevesoltys/seedvault/metadata/Metadata.kt

@@ -17,7 +17,7 @@ internal const val JSON_TOKEN = "token"
 internal const val JSON_ANDROID_VERSION = "androidVersion"
 internal const val JSON_DEVICE_NAME = "deviceName"
 
-class DecryptionFailedException(cause: Throwable) : Exception(cause)
+internal class DecryptionFailedException(cause: Throwable) : Exception(cause)
 
 class EncryptedBackupMetadata private constructor(val token: Long, val inputStream: InputStream?, val error: Boolean) {
     constructor(token: Long, inputStream: InputStream) : this(token, inputStream, false)

app/src/main/java/com/stevesoltys/seedvault/metadata/MetadataModule.kt

@@ -0,0 +1,8 @@
+package com.stevesoltys.seedvault.metadata
+
+import org.koin.dsl.module
+
+val metadataModule = module {
+    single<MetadataWriter> { MetadataWriterImpl(get()) }
+    single<MetadataReader> { MetadataReaderImpl(get()) }
+}

app/src/main/java/com/stevesoltys/seedvault/metadata/MetadataReader.kt

@@ -18,7 +18,7 @@ interface MetadataReader {
 
 }
 
-class MetadataReaderImpl(private val crypto: Crypto) : MetadataReader {
+internal class MetadataReaderImpl(private val crypto: Crypto) : MetadataReader {
 
     @Throws(SecurityException::class, DecryptionFailedException::class, UnsupportedVersionException::class, IOException::class)
     override fun readMetadata(inputStream: InputStream, expectedToken: Long): BackupMetadata {

app/src/main/java/com/stevesoltys/seedvault/metadata/MetadataWriter.kt

@@ -14,7 +14,7 @@ interface MetadataWriter {
 
 }
 
-class MetadataWriterImpl(private val crypto: Crypto): MetadataWriter {
+internal class MetadataWriterImpl(private val crypto: Crypto): MetadataWriter {
 
     @Throws(IOException::class)
     override fun write(outputStream: OutputStream, token: Long) {

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderBackupPlugin.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.seedvault.transport.backup.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.pm.PackageManager
 import com.stevesoltys.seedvault.transport.backup.BackupPlugin
@@ -7,7 +7,7 @@ import com.stevesoltys.seedvault.transport.backup.KVBackupPlugin
 import java.io.IOException
 import java.io.OutputStream
 
-class DocumentsProviderBackupPlugin(
+internal class DocumentsProviderBackupPlugin(
         private val storage: DocumentsStorage,
         packageManager: PackageManager) : BackupPlugin {
 

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderFullBackup.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.seedvault.transport.backup.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.pm.PackageInfo
 import android.util.Log
@@ -9,7 +9,7 @@ import java.io.OutputStream
 
 private val TAG = DocumentsProviderFullBackup::class.java.simpleName
 
-class DocumentsProviderFullBackup(
+internal class DocumentsProviderFullBackup(
         private val storage: DocumentsStorage) : FullBackupPlugin {
 
     override fun getQuota() = DEFAULT_QUOTA_FULL_BACKUP

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderFullRestorePlugin.kt

@@ -1,12 +1,11 @@
-package com.stevesoltys.seedvault.transport.restore.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.pm.PackageInfo
-import com.stevesoltys.seedvault.transport.backup.plugins.DocumentsStorage
 import com.stevesoltys.seedvault.transport.restore.FullRestorePlugin
 import java.io.IOException
 import java.io.InputStream
 
-class DocumentsProviderFullRestorePlugin(
+internal class DocumentsProviderFullRestorePlugin(
         private val documentsStorage: DocumentsStorage) : FullRestorePlugin {
 
     @Throws(IOException::class)

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderKVBackup.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.seedvault.transport.backup.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.pm.PackageInfo
 import androidx.documentfile.provider.DocumentFile
@@ -7,7 +7,7 @@ import com.stevesoltys.seedvault.transport.backup.KVBackupPlugin
 import java.io.IOException
 import java.io.OutputStream
 
-class DocumentsProviderKVBackup(private val storage: DocumentsStorage) : KVBackupPlugin {
+internal class DocumentsProviderKVBackup(private val storage: DocumentsStorage) : KVBackupPlugin {
 
     private var packageFile: DocumentFile? = null
 

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderKVRestorePlugin.kt

@@ -1,14 +1,12 @@
-package com.stevesoltys.seedvault.transport.restore.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.pm.PackageInfo
 import androidx.documentfile.provider.DocumentFile
-import com.stevesoltys.seedvault.transport.backup.plugins.DocumentsStorage
-import com.stevesoltys.seedvault.transport.backup.plugins.assertRightFile
 import com.stevesoltys.seedvault.transport.restore.KVRestorePlugin
 import java.io.IOException
 import java.io.InputStream
 
-class DocumentsProviderKVRestorePlugin(private val storage: DocumentsStorage) : KVRestorePlugin {
+internal class DocumentsProviderKVRestorePlugin(private val storage: DocumentsStorage) : KVRestorePlugin {
 
     private var packageDir: DocumentFile? = null
 

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderModule.kt

@@ -0,0 +1,12 @@
+package com.stevesoltys.seedvault.plugins.saf
+
+import com.stevesoltys.seedvault.transport.backup.BackupPlugin
+import com.stevesoltys.seedvault.transport.restore.RestorePlugin
+import org.koin.android.ext.koin.androidContext
+import org.koin.dsl.module
+
+val documentsProviderModule = module {
+    single { DocumentsStorage(androidContext(), get()) }
+    single<BackupPlugin> { DocumentsProviderBackupPlugin(get(), androidContext().packageManager) }
+    single<RestorePlugin> { DocumentsProviderRestorePlugin(androidContext(), get()) }
+}

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsProviderRestorePlugin.kt

@@ -0,0 +1,89 @@
+package com.stevesoltys.seedvault.plugins.saf
+
+import android.content.Context
+import android.net.Uri
+import android.util.Log
+import androidx.annotation.WorkerThread
+import androidx.documentfile.provider.DocumentFile
+import com.stevesoltys.seedvault.metadata.EncryptedBackupMetadata
+import com.stevesoltys.seedvault.transport.restore.FullRestorePlugin
+import com.stevesoltys.seedvault.transport.restore.KVRestorePlugin
+import com.stevesoltys.seedvault.transport.restore.RestorePlugin
+import java.io.IOException
+
+private val TAG = DocumentsProviderRestorePlugin::class.java.simpleName
+
+internal class DocumentsProviderRestorePlugin(
+        private val context: Context,
+        private val storage: DocumentsStorage) : RestorePlugin {
+
+    override val kvRestorePlugin: KVRestorePlugin by lazy {
+        DocumentsProviderKVRestorePlugin(storage)
+    }
+
+    override val fullRestorePlugin: FullRestorePlugin by lazy {
+        DocumentsProviderFullRestorePlugin(storage)
+    }
+
+    @WorkerThread
+    override fun hasBackup(uri: Uri): Boolean {
+        val parent = DocumentFile.fromTreeUri(context, uri) ?: throw AssertionError()
+        val rootDir = parent.findFileBlocking(context, DIRECTORY_ROOT) ?: return false
+        val backupSets = getBackups(context, rootDir)
+        return backupSets.isNotEmpty()
+    }
+
+    override fun getAvailableBackups(): Sequence<EncryptedBackupMetadata>? {
+        val rootDir = storage.rootBackupDir ?: return null
+        val backupSets = getBackups(context, rootDir)
+        val iterator = backupSets.iterator()
+        return generateSequence {
+            if (!iterator.hasNext()) return@generateSequence null  // end sequence
+            val backupSet = iterator.next()
+            try {
+                val stream = storage.getInputStream(backupSet.metadataFile)
+                EncryptedBackupMetadata(backupSet.token, stream)
+            } catch (e: IOException) {
+                Log.e(TAG, "Error getting InputStream for backup metadata.", e)
+                EncryptedBackupMetadata(backupSet.token)
+            }
+        }
+    }
+
+    @WorkerThread
+    fun getBackups(context: Context, rootDir: DocumentFile): List<BackupSet> {
+        val backupSets = ArrayList<BackupSet>()
+        val files = try {
+            // block until the DocumentsProvider has results
+            rootDir.listFilesBlocking(context)
+        } catch (e: IOException) {
+            Log.e(TAG, "Error loading backups from storage", e)
+            return backupSets
+        }
+        for (set in files) {
+            if (!set.isDirectory || set.name == null) {
+                if (set.name != FILE_NO_MEDIA) {
+                    Log.w(TAG, "Found invalid backup set folder: ${set.name}")
+                }
+                continue
+            }
+            val token = try {
+                set.name!!.toLong()
+            } catch (e: NumberFormatException) {
+                Log.w(TAG, "Found invalid backup set folder: ${set.name}")
+                continue
+            }
+            // block until children of set are available
+            val metadata = set.findFileBlocking(context, FILE_BACKUP_METADATA)
+            if (metadata == null) {
+                Log.w(TAG, "Missing metadata file in backup set folder: ${set.name}")
+            } else {
+                backupSets.add(BackupSet(token, metadata))
+            }
+        }
+        return backupSets
+    }
+
+}
+
+class BackupSet(val token: Long, val metadataFile: DocumentFile)

app/src/main/java/com/stevesoltys/seedvault/plugins/saf/DocumentsStorage.kt

@@ -1,4 +1,4 @@
-package com.stevesoltys.seedvault.transport.backup.plugins
+package com.stevesoltys.seedvault.plugins.saf
 
 import android.annotation.SuppressLint
 import android.content.Context
@@ -26,7 +26,9 @@ private const val MIME_TYPE = "application/octet-stream"
 
 private val TAG = DocumentsStorage::class.java.simpleName
 
-class DocumentsStorage(private val context: Context, private val settingsManager: SettingsManager) {
+internal class DocumentsStorage(
+        private val context: Context,
+        private val settingsManager: SettingsManager) {
 
     private val storage: Storage? = settingsManager.getStorage()
     private val token: Long = settingsManager.getBackupToken()

app/src/main/java/com/stevesoltys/seedvault/restore/RestoreActivity.kt

@@ -3,19 +3,18 @@ package com.stevesoltys.seedvault.restore
 import android.os.Bundle
 import androidx.annotation.CallSuper
 import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.ui.RequireProvisioningActivity
 import com.stevesoltys.seedvault.ui.RequireProvisioningViewModel
+import org.koin.androidx.viewmodel.ext.android.viewModel
 
 class RestoreActivity : RequireProvisioningActivity() {
 
-    private lateinit var viewModel: RestoreViewModel
+    private val viewModel: RestoreViewModel by viewModel()
 
     override fun getViewModel(): RequireProvisioningViewModel = viewModel
 
     override fun onCreate(savedInstanceState: Bundle?) {
-        viewModel = ViewModelProviders.of(this).get(RestoreViewModel::class.java)
         super.onCreate(savedInstanceState)
 
         if (isSetupWizard) hideSystemUI()

app/src/main/java/com/stevesoltys/seedvault/restore/RestoreProgressFragment.kt

@@ -10,16 +10,18 @@ import android.view.ViewGroup
 import android.view.WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.getAppName
 import com.stevesoltys.seedvault.isDebugBuild
+import com.stevesoltys.seedvault.settings.SettingsManager
 import kotlinx.android.synthetic.main.fragment_restore_progress.*
+import org.koin.android.ext.android.inject
+import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 
 class RestoreProgressFragment : Fragment() {
 
-    private lateinit var viewModel: RestoreViewModel
+    private val viewModel: RestoreViewModel by sharedViewModel()
+    private val settingsManager: SettingsManager by inject()
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
@@ -32,8 +34,6 @@ class RestoreProgressFragment : Fragment() {
         // decryption will fail when the device is locked, so keep the screen on to prevent locking
         requireActivity().window.addFlags(FLAG_KEEP_SCREEN_ON)
 
-        viewModel = ViewModelProviders.of(requireActivity()).get(RestoreViewModel::class.java)
-
         viewModel.chosenRestoreSet.observe(this, Observer { set ->
             backupNameView.text = set.device
         })
@@ -50,7 +50,6 @@ class RestoreProgressFragment : Fragment() {
             if (finished == 0) {
                 // success
                 currentPackageView.text = getString(R.string.restore_finished_success)
-                val settingsManager = (requireContext().applicationContext as Backup).settingsManager
                 warningView.text = if (settingsManager.getStorage()?.isUsb == true) {
                     getString(R.string.restore_finished_warning_only_installed, getString(R.string.restore_finished_warning_ejectable))
                 } else {

app/src/main/java/com/stevesoltys/seedvault/restore/RestoreSetFragment.kt

@@ -9,13 +9,13 @@ import android.view.View.VISIBLE
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import kotlinx.android.synthetic.main.fragment_restore_set.*
+import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 
 class RestoreSetFragment : Fragment() {
 
-    private lateinit var viewModel: RestoreViewModel
+    private val viewModel: RestoreViewModel by sharedViewModel()
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
@@ -24,7 +24,6 @@ class RestoreSetFragment : Fragment() {
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
-        viewModel = ViewModelProviders.of(requireActivity()).get(RestoreViewModel::class.java)
 
         viewModel.restoreSets.observe(this, Observer { result -> onRestoreSetsLoaded(result) })
 

app/src/main/java/com/stevesoltys/seedvault/restore/RestoreViewModel.kt

@@ -1,6 +1,7 @@
 package com.stevesoltys.seedvault.restore
 
 import android.app.Application
+import android.app.backup.IBackupManager
 import android.app.backup.IRestoreObserver
 import android.app.backup.IRestoreSession
 import android.app.backup.RestoreSet
@@ -9,20 +10,25 @@ import android.util.Log
 import androidx.annotation.WorkerThread
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
-import com.stevesoltys.seedvault.Backup
-import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.BackupMonitor
+import com.stevesoltys.seedvault.R
+import com.stevesoltys.seedvault.crypto.KeyManager
+import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.transport.TRANSPORT_ID
+import com.stevesoltys.seedvault.transport.restore.RestorePlugin
 import com.stevesoltys.seedvault.ui.RequireProvisioningViewModel
 
 private val TAG = RestoreViewModel::class.java.simpleName
 
-class RestoreViewModel(app: Application) : RequireProvisioningViewModel(app), RestoreSetClickListener {
+internal class RestoreViewModel(
+        app: Application,
+        settingsManager: SettingsManager,
+        keyManager: KeyManager,
+        private val backupManager: IBackupManager
+) : RequireProvisioningViewModel(app, settingsManager, keyManager), RestoreSetClickListener {
 
     override val isRestoreOperation = true
 
-    private val backupManager = Backup.backupManager
-
     private var session: IRestoreSession? = null
     private var observer: RestoreObserver? = null
     private val monitor = BackupMonitor()

app/src/main/java/com/stevesoltys/seedvault/settings/BackupManagerSettings.kt

@@ -2,7 +2,6 @@ package com.stevesoltys.seedvault.settings
 
 import android.content.ContentResolver
 import android.provider.Settings
-import java.util.concurrent.TimeUnit
 import java.util.concurrent.TimeUnit.DAYS
 
 private val SETTING = Settings.Secure.BACKUP_MANAGER_CONSTANTS

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsActivity.kt

@@ -2,20 +2,21 @@ package com.stevesoltys.seedvault.settings
 
 import android.os.Bundle
 import androidx.annotation.CallSuper
-import androidx.lifecycle.ViewModelProviders
+import com.stevesoltys.seedvault.BackupNotificationManager
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.ui.RequireProvisioningActivity
 import com.stevesoltys.seedvault.ui.RequireProvisioningViewModel
+import org.koin.android.ext.android.inject
+import org.koin.androidx.viewmodel.ext.android.viewModel
 
 class SettingsActivity : RequireProvisioningActivity() {
 
-    private lateinit var viewModel: SettingsViewModel
+    private val viewModel: SettingsViewModel by viewModel()
+    private val notificationManager: BackupNotificationManager by inject()
 
     override fun getViewModel(): RequireProvisioningViewModel = viewModel
 
     override fun onCreate(savedInstanceState: Bundle?) {
-        viewModel = ViewModelProviders.of(this).get(SettingsViewModel::class.java)
         super.onCreate(savedInstanceState)
 
         setContentView(R.layout.activity_fragment_container)
@@ -36,7 +37,7 @@ class SettingsActivity : RequireProvisioningActivity() {
         } else if (!viewModel.validLocationIsSet()) {
             showStorageActivity()
             // remove potential error notifications
-            (application as Backup).notificationManager.onBackupErrorSeen()
+            notificationManager.onBackupErrorSeen()
         }
     }
 

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsFragment.kt

@@ -1,5 +1,6 @@
 package com.stevesoltys.seedvault.settings
 
+import android.app.backup.IBackupManager
 import android.content.Context
 import android.content.Context.BACKUP_SERVICE
 import android.content.Intent
@@ -17,26 +18,25 @@ import android.util.Log
 import android.view.Menu
 import android.view.MenuInflater
 import android.view.MenuItem
-import androidx.lifecycle.ViewModelProviders
 import androidx.preference.Preference
 import androidx.preference.Preference.OnPreferenceChangeListener
 import androidx.preference.PreferenceFragmentCompat
 import androidx.preference.TwoStatePreference
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.UsbMonitor
 import com.stevesoltys.seedvault.isMassStorage
 import com.stevesoltys.seedvault.restore.RestoreActivity
+import org.koin.android.ext.android.inject
+import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 import java.util.*
 
 private val TAG = SettingsFragment::class.java.name
 
 class SettingsFragment : PreferenceFragmentCompat() {
 
-    private val backupManager = Backup.backupManager
+    private val viewModel: SettingsViewModel by sharedViewModel()
-
+    private val settingsManager: SettingsManager by inject()
-    private lateinit var viewModel: SettingsViewModel
+    private val backupManager: IBackupManager by inject()
-    private lateinit var settingsManager: SettingsManager
 
     private lateinit var backup: TwoStatePreference
     private lateinit var autoRestore: TwoStatePreference
@@ -63,9 +63,6 @@ class SettingsFragment : PreferenceFragmentCompat() {
         setPreferencesFromResource(R.xml.settings, rootKey)
         setHasOptionsMenu(true)
 
-        viewModel = ViewModelProviders.of(requireActivity()).get(SettingsViewModel::class.java)
-        settingsManager = (requireContext().applicationContext as Backup).settingsManager
-
         backup = findPreference<TwoStatePreference>("backup")!!
         backup.onPreferenceChangeListener = OnPreferenceChangeListener { _, newValue ->
             val enabled = newValue as Boolean

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsManager.kt

@@ -18,12 +18,12 @@ private const val PREF_KEY_FLASH_DRIVE_PRODUCT_ID = "flashDriveProductId"
 
 private const val PREF_KEY_BACKUP_TOKEN = "backupToken"
 private const val PREF_KEY_BACKUP_TIME = "backupTime"
-private const val PREF_KEY_BACKUP_PASSWORD = "backupLegacyPassword"
 
 class SettingsManager(context: Context) {
 
     private val prefs = PreferenceManager.getDefaultSharedPreferences(context)
 
+    // FIXME Storage is currently plugin specific and not generic
     fun setStorage(storage: Storage) {
         prefs.edit()
                 .putString(PREF_KEY_STORAGE_URI, storage.uri.toString())
@@ -108,11 +108,6 @@ class SettingsManager(context: Context) {
         return prefs.getLong(PREF_KEY_BACKUP_TIME, 0L)
     }
 
-    @Deprecated("Replaced by KeyManager#getBackupKey()")
-    fun getBackupPassword(): String? {
-        return prefs.getString(PREF_KEY_BACKUP_PASSWORD, null)
-    }
-
 }
 
 data class Storage(

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsViewModel.kt

@@ -1,10 +1,15 @@
 package com.stevesoltys.seedvault.settings
 
 import android.app.Application
+import com.stevesoltys.seedvault.crypto.KeyManager
 import com.stevesoltys.seedvault.transport.requestBackup
 import com.stevesoltys.seedvault.ui.RequireProvisioningViewModel
 
-class SettingsViewModel(app: Application) : RequireProvisioningViewModel(app) {
+class SettingsViewModel(
+        app: Application,
+        settingsManager: SettingsManager,
+        keyManager: KeyManager
+) : RequireProvisioningViewModel(app, settingsManager, keyManager) {
 
     override val isRestoreOperation = false
 

app/src/main/java/com/stevesoltys/seedvault/transport/ConfigurableBackupTransport.kt

@@ -10,6 +10,10 @@ import android.content.pm.PackageInfo
 import android.os.ParcelFileDescriptor
 import android.util.Log
 import com.stevesoltys.seedvault.settings.SettingsActivity
+import com.stevesoltys.seedvault.transport.backup.BackupCoordinator
+import com.stevesoltys.seedvault.transport.restore.RestoreCoordinator
+import org.koin.core.KoinComponent
+import org.koin.core.inject
 
 val TRANSPORT_ID: String = ConfigurableBackupTransport::class.java.name
 
@@ -20,11 +24,10 @@ private val TAG = ConfigurableBackupTransport::class.java.simpleName
  * @author Steve Soltys
  * @author Torsten Grote
  */
-class ConfigurableBackupTransport internal constructor(private val context: Context) : BackupTransport() {
+class ConfigurableBackupTransport internal constructor(private val context: Context) : BackupTransport(), KoinComponent {
 
-    private val pluginManager = PluginManager(context)
+    private val backupCoordinator by inject<BackupCoordinator>()
-    private val backupCoordinator = pluginManager.backupCoordinator
+    private val restoreCoordinator by inject<RestoreCoordinator>()
-    private val restoreCoordinator = pluginManager.restoreCoordinator
 
     override fun transportDirName(): String {
         return TRANSPORT_DIRECTORY_NAME

app/src/main/java/com/stevesoltys/seedvault/transport/ConfigurableBackupTransportService.kt

@@ -2,19 +2,21 @@ package com.stevesoltys.seedvault.transport
 
 import android.app.Service
 import android.app.backup.BackupManager
-import android.content.Context
-import android.content.Context.BACKUP_SERVICE
 import android.app.backup.BackupManager.FLAG_NON_INCREMENTAL_BACKUP
 import android.app.backup.BackupTransport.FLAG_USER_INITIATED
+import android.app.backup.IBackupManager
+import android.content.Context
+import android.content.Context.BACKUP_SERVICE
 import android.content.Intent
 import android.os.IBinder
 import android.os.RemoteException
 import android.util.Log
 import androidx.annotation.WorkerThread
-import com.stevesoltys.seedvault.Backup
+import com.stevesoltys.seedvault.BackupMonitor
+import com.stevesoltys.seedvault.BackupNotificationManager
 import com.stevesoltys.seedvault.NotificationBackupObserver
 import com.stevesoltys.seedvault.R
-import com.stevesoltys.seedvault.BackupMonitor
+import org.koin.core.context.GlobalContext.get
 
 private val TAG = ConfigurableBackupTransportService::class.java.simpleName
 
@@ -50,17 +52,18 @@ class ConfigurableBackupTransportService : Service() {
 @WorkerThread
 fun requestBackup(context: Context) {
     // show notification
-    val nm = (context.applicationContext as Backup).notificationManager
+    val nm: BackupNotificationManager = get().koin.get()
     nm.onBackupUpdate(context.getString(R.string.notification_backup_starting), 0, 1, true)
 
     val observer = NotificationBackupObserver(context, true)
     val flags = FLAG_NON_INCREMENTAL_BACKUP or FLAG_USER_INITIATED
-    val packages = PackageService().eligiblePackages
+    val packages = PackageService.eligiblePackages
     val result = try {
-        Backup.backupManager.requestBackup(packages, observer, BackupMonitor(), flags)
+        val backupManager: IBackupManager = get().koin.get()
+        backupManager.requestBackup(packages, observer, BackupMonitor(), flags)
     } catch (e: RemoteException) {
-        // TODO show notification on backup error
         Log.e(TAG, "Error during backup: ", e)
+        nm.onBackupError()
     }
     if (result == BackupManager.SUCCESS) {
         Log.i(TAG, "Backup succeeded ")

app/src/main/java/com/stevesoltys/seedvault/transport/PackageService.kt

@@ -1,5 +1,6 @@
 package com.stevesoltys.seedvault.transport
 
+import android.app.backup.IBackupManager
 import android.content.pm.IPackageManager
 import android.content.pm.PackageInfo
 import android.os.RemoteException
@@ -7,8 +8,9 @@ import android.os.ServiceManager.getService
 import android.os.UserHandle
 import android.util.Log
 import com.google.android.collect.Sets.newArraySet
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.MAGIC_PACKAGE_MANAGER
+import org.koin.core.KoinComponent
+import org.koin.core.inject
 import java.util.*
 
 private val TAG = PackageService::class.java.simpleName
@@ -27,9 +29,9 @@ private val IGNORED_PACKAGES = newArraySet(
  * @author Steve Soltys
  * @author Torsten Grote
  */
-internal class PackageService {
+internal object PackageService : KoinComponent {
 
-    private val backupManager = Backup.backupManager
+    private val backupManager: IBackupManager by inject()
     private val packageManager: IPackageManager = IPackageManager.Stub.asInterface(getService("package"))
 
     val eligiblePackages: Array<String>

app/src/main/java/com/stevesoltys/seedvault/transport/PluginManager.kt

@@ -1,54 +0,0 @@
-package com.stevesoltys.seedvault.transport
-
-import android.content.Context
-import com.stevesoltys.seedvault.Backup
-import com.stevesoltys.seedvault.crypto.CipherFactoryImpl
-import com.stevesoltys.seedvault.crypto.CryptoImpl
-import com.stevesoltys.seedvault.header.HeaderReaderImpl
-import com.stevesoltys.seedvault.header.HeaderWriterImpl
-import com.stevesoltys.seedvault.metadata.MetadataReaderImpl
-import com.stevesoltys.seedvault.metadata.MetadataWriterImpl
-import com.stevesoltys.seedvault.transport.backup.BackupCoordinator
-import com.stevesoltys.seedvault.transport.backup.FullBackup
-import com.stevesoltys.seedvault.transport.backup.InputFactory
-import com.stevesoltys.seedvault.transport.backup.KVBackup
-import com.stevesoltys.seedvault.transport.backup.plugins.DocumentsProviderBackupPlugin
-import com.stevesoltys.seedvault.transport.backup.plugins.DocumentsStorage
-import com.stevesoltys.seedvault.transport.restore.FullRestore
-import com.stevesoltys.seedvault.transport.restore.KVRestore
-import com.stevesoltys.seedvault.transport.restore.OutputFactory
-import com.stevesoltys.seedvault.transport.restore.RestoreCoordinator
-import com.stevesoltys.seedvault.transport.restore.plugins.DocumentsProviderRestorePlugin
-
-class PluginManager(context: Context) {
-
-    // We can think about using an injection framework such as Dagger, Koin or Kodein to simplify this.
-
-    private val settingsManager = (context.applicationContext as Backup).settingsManager
-    private val storage = DocumentsStorage(context, settingsManager)
-
-    private val headerWriter = HeaderWriterImpl()
-    private val headerReader = HeaderReaderImpl()
-    private val cipherFactory = CipherFactoryImpl(Backup.keyManager)
-    private val crypto = CryptoImpl(cipherFactory, headerWriter, headerReader)
-    private val metadataWriter = MetadataWriterImpl(crypto)
-    private val metadataReader = MetadataReaderImpl(crypto)
-
-
-    private val backupPlugin = DocumentsProviderBackupPlugin(storage, context.packageManager)
-    private val inputFactory = InputFactory()
-    private val kvBackup = KVBackup(backupPlugin.kvBackupPlugin, inputFactory, headerWriter, crypto)
-    private val fullBackup = FullBackup(backupPlugin.fullBackupPlugin, inputFactory, headerWriter, crypto)
-    private val notificationManager = (context.applicationContext as Backup).notificationManager
-
-    internal val backupCoordinator = BackupCoordinator(context, backupPlugin, kvBackup, fullBackup, metadataWriter, settingsManager, notificationManager)
-
-
-    private val restorePlugin = DocumentsProviderRestorePlugin(storage)
-    private val outputFactory = OutputFactory()
-    private val kvRestore = KVRestore(restorePlugin.kvRestorePlugin, outputFactory, headerReader, crypto)
-    private val fullRestore = FullRestore(restorePlugin.fullRestorePlugin, outputFactory, headerReader, crypto)
-
-    internal val restoreCoordinator = RestoreCoordinator(context, settingsManager, restorePlugin, kvRestore, fullRestore, metadataReader)
-
-}

app/src/main/java/com/stevesoltys/seedvault/transport/backup/BackupCoordinator.kt

@@ -18,7 +18,7 @@ private val TAG = BackupCoordinator::class.java.simpleName
  * @author Steve Soltys
  * @author Torsten Grote
  */
-class BackupCoordinator(
+internal class BackupCoordinator(
         private val context: Context,
         private val plugin: BackupPlugin,
         private val kv: KVBackup,

app/src/main/java/com/stevesoltys/seedvault/transport/backup/BackupModule.kt

@@ -0,0 +1,11 @@
+package com.stevesoltys.seedvault.transport.backup
+
+import org.koin.android.ext.koin.androidContext
+import org.koin.dsl.module
+
+val backupModule = module {
+    single { InputFactory() }
+    single { KVBackup(get<BackupPlugin>().kvBackupPlugin, get(), get(), get()) }
+    single { FullBackup(get<BackupPlugin>().fullBackupPlugin, get(), get(), get()) }
+    single { BackupCoordinator(androidContext(), get(), get(), get(), get(), get(), get()) }
+}

app/src/main/java/com/stevesoltys/seedvault/transport/backup/FullBackup.kt

@@ -26,7 +26,7 @@ const val DEFAULT_QUOTA_FULL_BACKUP = (2 * (25 * 1024 * 1024)).toLong()
 
 private val TAG = FullBackup::class.java.simpleName
 
-class FullBackup(
+internal class FullBackup(
         private val plugin: FullBackupPlugin,
         private val inputFactory: InputFactory,
         private val headerWriter: HeaderWriter,

app/src/main/java/com/stevesoltys/seedvault/transport/backup/InputFactory.kt

@@ -8,7 +8,7 @@ import java.io.InputStream
 /**
  * This class exists for easier testing, so we can mock it and return custom data inputs.
  */
-class InputFactory {
+internal class InputFactory {
 
     fun getBackupDataInput(inputFileDescriptor: ParcelFileDescriptor): BackupDataInput {
         return BackupDataInput(inputFileDescriptor.fileDescriptor)

app/src/main/java/com/stevesoltys/seedvault/transport/backup/KVBackup.kt

@@ -17,7 +17,7 @@ const val DEFAULT_QUOTA_KEY_VALUE_BACKUP = (2 * (5 * 1024 * 1024)).toLong()
 
 private val TAG = KVBackup::class.java.simpleName
 
-class KVBackup(
+internal class KVBackup(
         private val plugin: KVBackupPlugin,
         private val inputFactory: InputFactory,
         private val headerWriter: HeaderWriter,

app/src/main/java/com/stevesoltys/seedvault/transport/restore/OutputFactory.kt

@@ -8,7 +8,7 @@ import java.io.OutputStream
 /**
  * This class exists for easier testing, so we can mock it and return custom data outputs.
  */
-class OutputFactory {
+internal class OutputFactory {
 
     fun getBackupDataOutput(outputFileDescriptor: ParcelFileDescriptor): BackupDataOutput {
         return BackupDataOutput(outputFileDescriptor.fileDescriptor)

app/src/main/java/com/stevesoltys/seedvault/transport/restore/RestoreCoordinator.kt

@@ -5,7 +5,6 @@ import android.app.backup.BackupTransport.TRANSPORT_OK
 import android.app.backup.RestoreDescription
 import android.app.backup.RestoreDescription.*
 import android.app.backup.RestoreSet
-import android.content.Context
 import android.content.pm.PackageInfo
 import android.os.ParcelFileDescriptor
 import android.util.Log
@@ -23,7 +22,6 @@ private class RestoreCoordinatorState(
 private val TAG = RestoreCoordinator::class.java.simpleName
 
 internal class RestoreCoordinator(
-        private val context: Context,
         private val settingsManager: SettingsManager,
         private val plugin: RestorePlugin,
         private val kv: KVRestore,
@@ -39,7 +37,7 @@ internal class RestoreCoordinator(
      *   or null if an error occurred (the attempt should be rescheduled).
      **/
     fun getAvailableRestoreSets(): Array<RestoreSet>? {
-        val availableBackups = plugin.getAvailableBackups(context) ?: return null
+        val availableBackups = plugin.getAvailableBackups() ?: return null
         val restoreSets = ArrayList<RestoreSet>()
         for (encryptedMetadata in availableBackups) {
             if (encryptedMetadata.error) continue

app/src/main/java/com/stevesoltys/seedvault/transport/restore/RestoreModule.kt

@@ -0,0 +1,10 @@
+package com.stevesoltys.seedvault.transport.restore
+
+import org.koin.dsl.module
+
+val restoreModule = module {
+    single { OutputFactory() }
+    single { KVRestore(get<RestorePlugin>().kvRestorePlugin, get(), get(), get()) }
+    single { FullRestore(get<RestorePlugin>().fullRestorePlugin, get(), get(), get()) }
+    single { RestoreCoordinator(get(), get(), get(), get(), get()) }
+}

app/src/main/java/com/stevesoltys/seedvault/transport/restore/RestorePlugin.kt

@@ -1,6 +1,7 @@
 package com.stevesoltys.seedvault.transport.restore
 
-import android.content.Context
+import android.net.Uri
+import androidx.annotation.WorkerThread
 import com.stevesoltys.seedvault.metadata.EncryptedBackupMetadata
 
 interface RestorePlugin {
@@ -15,6 +16,15 @@ interface RestorePlugin {
      * @return metadata for the set of restore images available,
      * or null if an error occurred (the attempt should be rescheduled).
      **/
-    fun getAvailableBackups(context: Context): Sequence<EncryptedBackupMetadata>?
+    fun getAvailableBackups(): Sequence<EncryptedBackupMetadata>?
+
+    /**
+     * Searches if there's really a backup available in the given location.
+     * Returns true if at least one was found and false otherwise.
+     *
+     * FIXME: Passing a Uri is maybe too plugin-specific?
+     */
+    @WorkerThread
+    fun hasBackup(uri: Uri): Boolean
 
 }

app/src/main/java/com/stevesoltys/seedvault/transport/restore/plugins/DocumentsProviderRestorePlugin.kt

@@ -1,81 +0,0 @@
-package com.stevesoltys.seedvault.transport.restore.plugins
-
-import android.content.Context
-import android.util.Log
-import androidx.annotation.WorkerThread
-import androidx.documentfile.provider.DocumentFile
-import com.stevesoltys.seedvault.metadata.EncryptedBackupMetadata
-import com.stevesoltys.seedvault.transport.backup.plugins.*
-import com.stevesoltys.seedvault.transport.restore.FullRestorePlugin
-import com.stevesoltys.seedvault.transport.restore.KVRestorePlugin
-import com.stevesoltys.seedvault.transport.restore.RestorePlugin
-import java.io.IOException
-
-private val TAG = DocumentsProviderRestorePlugin::class.java.simpleName
-
-class DocumentsProviderRestorePlugin(private val storage: DocumentsStorage) : RestorePlugin {
-
-    override val kvRestorePlugin: KVRestorePlugin by lazy {
-        DocumentsProviderKVRestorePlugin(storage)
-    }
-
-    override val fullRestorePlugin: FullRestorePlugin by lazy {
-        DocumentsProviderFullRestorePlugin(storage)
-    }
-
-    override fun getAvailableBackups(context: Context): Sequence<EncryptedBackupMetadata>? {
-        val rootDir = storage.rootBackupDir ?: return null
-        val backupSets = getBackups(context, rootDir)
-        val iterator = backupSets.iterator()
-        return generateSequence {
-            if (!iterator.hasNext()) return@generateSequence null  // end sequence
-            val backupSet = iterator.next()
-            try {
-                val stream = storage.getInputStream(backupSet.metadataFile)
-                EncryptedBackupMetadata(backupSet.token, stream)
-            } catch (e: IOException) {
-                Log.e(TAG, "Error getting InputStream for backup metadata.", e)
-                EncryptedBackupMetadata(backupSet.token)
-            }
-        }
-    }
-
-    companion object {
-        @WorkerThread
-        fun getBackups(context: Context, rootDir: DocumentFile): List<BackupSet> {
-            val backupSets = ArrayList<BackupSet>()
-            val files = try {
-                // block until the DocumentsProvider has results
-                rootDir.listFilesBlocking(context)
-            } catch (e: IOException) {
-                Log.e(TAG, "Error loading backups from storage", e)
-                return backupSets
-            }
-            for (set in files) {
-                if (!set.isDirectory || set.name == null) {
-                    if (set.name != FILE_NO_MEDIA) {
-                        Log.w(TAG, "Found invalid backup set folder: ${set.name}")
-                    }
-                    continue
-                }
-                val token = try {
-                    set.name!!.toLong()
-                } catch (e: NumberFormatException) {
-                    Log.w(TAG, "Found invalid backup set folder: ${set.name}")
-                    continue
-                }
-                // block until children of set are available
-                val metadata = set.findFileBlocking(context, FILE_BACKUP_METADATA)
-                if (metadata == null) {
-                    Log.w(TAG, "Missing metadata file in backup set folder: ${set.name}")
-                } else {
-                    backupSets.add(BackupSet(token, metadata))
-                }
-            }
-            return backupSets
-        }
-    }
-
-}
-
-class BackupSet(val token: Long, val metadataFile: DocumentFile)

app/src/main/java/com/stevesoltys/seedvault/ui/RequireProvisioningViewModel.kt

@@ -2,10 +2,15 @@ package com.stevesoltys.seedvault.ui
 
 import android.app.Application
 import androidx.lifecycle.AndroidViewModel
-import com.stevesoltys.seedvault.Backup
+import com.stevesoltys.seedvault.crypto.KeyManager
+import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.ui.storage.StorageViewModel
 
-abstract class RequireProvisioningViewModel(protected val app: Application) : AndroidViewModel(app) {
+abstract class RequireProvisioningViewModel(
+        protected val app: Application,
+        private val settingsManager: SettingsManager,
+        private val keyManager: KeyManager
+) : AndroidViewModel(app) {
 
     abstract val isRestoreOperation: Boolean
 
@@ -13,8 +18,8 @@ abstract class RequireProvisioningViewModel(protected val app: Application) : An
     internal val chooseBackupLocation: LiveEvent<Boolean> get() = mChooseBackupLocation
     internal fun chooseBackupLocation() = mChooseBackupLocation.setEvent(true)
 
-    internal fun validLocationIsSet() = StorageViewModel.validLocationIsSet(app)
+    internal fun validLocationIsSet() = StorageViewModel.validLocationIsSet(app, settingsManager)
 
-    internal fun recoveryCodeIsSet() = Backup.keyManager.hasBackupKey()
+    internal fun recoveryCodeIsSet() = keyManager.hasBackupKey()
 
 }

app/src/main/java/com/stevesoltys/seedvault/ui/recoverycode/RecoveryCodeActivity.kt

@@ -2,16 +2,16 @@ package com.stevesoltys.seedvault.ui.recoverycode
 
 import android.os.Bundle
 import android.view.MenuItem
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.ui.BackupActivity
 import com.stevesoltys.seedvault.ui.INTENT_EXTRA_IS_RESTORE
 import com.stevesoltys.seedvault.ui.INTENT_EXTRA_IS_SETUP_WIZARD
 import com.stevesoltys.seedvault.ui.LiveEventHandler
+import org.koin.androidx.viewmodel.ext.android.viewModel
 
 class RecoveryCodeActivity : BackupActivity() {
 
-    private lateinit var viewModel: RecoveryCodeViewModel
+    private val viewModel: RecoveryCodeViewModel by viewModel()
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -20,7 +20,6 @@ class RecoveryCodeActivity : BackupActivity() {
 
         setContentView(R.layout.activity_recovery_code)
 
-        viewModel = ViewModelProviders.of(this).get(RecoveryCodeViewModel::class.java)
         viewModel.isRestore = isRestore()
         viewModel.confirmButtonClicked.observeEvent(this, LiveEventHandler { clicked ->
             if (clicked) showInput(true)

app/src/main/java/com/stevesoltys/seedvault/ui/recoverycode/RecoveryCodeInputFragment.kt

@@ -11,7 +11,6 @@ import android.widget.AutoCompleteTextView
 import android.widget.Toast
 import android.widget.Toast.LENGTH_LONG
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.isDebugBuild
 import io.github.novacrypto.bip39.Validation.InvalidChecksumException
@@ -19,10 +18,11 @@ import io.github.novacrypto.bip39.Validation.WordNotFoundException
 import io.github.novacrypto.bip39.wordlists.English
 import kotlinx.android.synthetic.main.fragment_recovery_code_input.*
 import kotlinx.android.synthetic.main.recovery_code_input.*
+import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 
 class RecoveryCodeInputFragment : Fragment() {
 
-    private lateinit var viewModel: RecoveryCodeViewModel
+    private val viewModel: RecoveryCodeViewModel by sharedViewModel()
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
@@ -31,7 +31,6 @@ class RecoveryCodeInputFragment : Fragment() {
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
-        viewModel = ViewModelProviders.of(requireActivity()).get(RecoveryCodeViewModel::class.java)
 
         if (viewModel.isRestore) {
             introText.setText(R.string.recovery_code_input_intro)

app/src/main/java/com/stevesoltys/seedvault/ui/recoverycode/RecoveryCodeOutputFragment.kt

@@ -6,15 +6,15 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
-import androidx.lifecycle.ViewModelProviders
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.stevesoltys.seedvault.R
 import kotlinx.android.synthetic.main.fragment_recovery_code_output.*
+import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 
 class RecoveryCodeOutputFragment : Fragment() {
 
-    private lateinit var viewModel: RecoveryCodeViewModel
+    private val viewModel: RecoveryCodeViewModel by sharedViewModel()
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                               savedInstanceState: Bundle?): View? {
@@ -23,7 +23,6 @@ class RecoveryCodeOutputFragment : Fragment() {
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
-        viewModel = ViewModelProviders.of(requireActivity()).get(RecoveryCodeViewModel::class.java)
 
         setGridParameters(wordList)
         wordList.adapter = RecoveryCodeAdapter(viewModel.wordList)

app/src/main/java/com/stevesoltys/seedvault/ui/recoverycode/RecoveryCodeViewModel.kt

@@ -1,8 +1,8 @@
 package com.stevesoltys.seedvault.ui.recoverycode
 
-import android.app.Application
 import androidx.lifecycle.AndroidViewModel
-import com.stevesoltys.seedvault.Backup
+import com.stevesoltys.seedvault.App
+import com.stevesoltys.seedvault.crypto.KeyManager
 import com.stevesoltys.seedvault.ui.LiveEvent
 import com.stevesoltys.seedvault.ui.MutableLiveEvent
 import io.github.novacrypto.bip39.*
@@ -17,7 +17,7 @@ import java.util.*
 internal const val WORD_NUM = 12
 internal const val WORD_LIST_SIZE = 2048
 
-class RecoveryCodeViewModel(application: Application) : AndroidViewModel(application) {
+class RecoveryCodeViewModel(app: App, private val keyManager: KeyManager) : AndroidViewModel(app) {
 
     internal val wordList: List<CharSequence> by lazy {
         val items: ArrayList<CharSequence> = ArrayList(WORD_NUM)
@@ -49,7 +49,7 @@ class RecoveryCodeViewModel(application: Application) : AndroidViewModel(applica
         }
         val mnemonic = input.joinToString(" ")
         val seed = SeedCalculator(JavaxPBKDF2WithHmacSHA512.INSTANCE).calculateSeed(mnemonic, "")
-        Backup.keyManager.storeBackupKey(seed)
+        keyManager.storeBackupKey(seed)
 
         mRecoveryCodeSaved.setEvent(true)
     }

app/src/main/java/com/stevesoltys/seedvault/ui/storage/BackupStorageViewModel.kt

@@ -2,19 +2,23 @@ package com.stevesoltys.seedvault.ui.storage
 
 import android.app.Application
 import android.app.backup.BackupProgress
+import android.app.backup.IBackupManager
 import android.app.backup.IBackupObserver
 import android.net.Uri
 import android.os.UserHandle
 import android.util.Log
 import androidx.annotation.WorkerThread
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.R
+import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.transport.TRANSPORT_ID
 import com.stevesoltys.seedvault.transport.requestBackup
 
 private val TAG = BackupStorageViewModel::class.java.simpleName
 
-internal class BackupStorageViewModel(private val app: Application) : StorageViewModel(app) {
+internal class BackupStorageViewModel(
+        private val app: Application,
+        private val backupManager: IBackupManager,
+        settingsManager: SettingsManager) : StorageViewModel(app, settingsManager) {
 
     override val isRestoreOperation = false
 
@@ -26,7 +30,7 @@ internal class BackupStorageViewModel(private val app: Application) : StorageVie
 
         // initialize the new location
         val observer = InitializationObserver()
-        Backup.backupManager.initializeTransportsForUser(UserHandle.myUserId(), arrayOf(TRANSPORT_ID), observer)
+        backupManager.initializeTransportsForUser(UserHandle.myUserId(), arrayOf(TRANSPORT_ID), observer)
 
         // if storage is on USB and this is not SetupWizard, do a backup right away
         if (isUsb && !isSetupWizard) Thread {

app/src/main/java/com/stevesoltys/seedvault/ui/storage/RestoreStorageViewModel.kt

@@ -3,21 +3,22 @@ package com.stevesoltys.seedvault.ui.storage
 import android.app.Application
 import android.net.Uri
 import android.util.Log
-import androidx.annotation.WorkerThread
-import androidx.documentfile.provider.DocumentFile
 import com.stevesoltys.seedvault.R
-import com.stevesoltys.seedvault.transport.backup.plugins.DIRECTORY_ROOT
+import com.stevesoltys.seedvault.settings.SettingsManager
-import com.stevesoltys.seedvault.transport.backup.plugins.findFileBlocking
+import com.stevesoltys.seedvault.plugins.saf.DIRECTORY_ROOT
-import com.stevesoltys.seedvault.transport.restore.plugins.DocumentsProviderRestorePlugin
+import com.stevesoltys.seedvault.transport.restore.RestorePlugin
 
 private val TAG = RestoreStorageViewModel::class.java.simpleName
 
-internal class RestoreStorageViewModel(private val app: Application) : StorageViewModel(app) {
+internal class RestoreStorageViewModel(
+        private val app: Application,
+        private val restorePlugin: RestorePlugin,
+        settingsManager: SettingsManager) : StorageViewModel(app, settingsManager) {
 
     override val isRestoreOperation = true
 
     override fun onLocationSet(uri: Uri) = Thread {
-        if (hasBackup(uri)) {
+        if (restorePlugin.hasBackup(uri)) {
             saveStorage(uri)
 
             mLocationChecked.postEvent(LocationResult())
@@ -30,21 +31,4 @@ internal class RestoreStorageViewModel(private val app: Application) : StorageVi
         }
     }.start()
 
-    /**
-     * Searches if there's really a backup available in the given location.
-     * Returns true if at least one was found and false otherwise.
-     *
-     * This method is not plugin-agnostic and breaks encapsulation.
-     * It is specific to the (currently only) DocumentsProvider plugin.
-     *
-     * TODO maybe move this to the RestoreCoordinator once we can inject it
-     */
-    @WorkerThread
-    private fun hasBackup(folderUri: Uri): Boolean {
-        val parent = DocumentFile.fromTreeUri(app, folderUri) ?: throw AssertionError()
-        val rootDir = parent.findFileBlocking(app, DIRECTORY_ROOT) ?: return false
-        val backupSets = DocumentsProviderRestorePlugin.getBackups(app, rootDir)
-        return backupSets.isNotEmpty()
-    }
-
 }

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageActivity.kt

@@ -5,12 +5,12 @@ import android.os.Bundle
 import android.util.Log
 import androidx.annotation.CallSuper
 import androidx.appcompat.app.AlertDialog
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.ui.BackupActivity
 import com.stevesoltys.seedvault.ui.INTENT_EXTRA_IS_RESTORE
 import com.stevesoltys.seedvault.ui.INTENT_EXTRA_IS_SETUP_WIZARD
 import com.stevesoltys.seedvault.ui.LiveEventHandler
+import org.koin.androidx.viewmodel.ext.android.getViewModel
 
 private val TAG = StorageActivity::class.java.name
 
@@ -27,9 +27,9 @@ class StorageActivity : BackupActivity() {
         setContentView(R.layout.activity_fragment_container)
 
         viewModel = if (isRestore()) {
-            ViewModelProviders.of(this).get(RestoreStorageViewModel::class.java)
+            getViewModel<RestoreStorageViewModel>()
         } else {
-            ViewModelProviders.of(this).get(BackupStorageViewModel::class.java)
+            getViewModel<BackupStorageViewModel>()
         }
         viewModel.isSetupWizard = isSetupWizard()
 

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageRootsFragment.kt

@@ -11,11 +11,11 @@ import android.view.ViewGroup
 import androidx.appcompat.app.AppCompatActivity.RESULT_OK
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
-import androidx.lifecycle.ViewModelProviders
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.ui.INTENT_EXTRA_IS_RESTORE
 import com.stevesoltys.seedvault.ui.REQUEST_CODE_OPEN_DOCUMENT_TREE
 import kotlinx.android.synthetic.main.fragment_storage_root.*
+import org.koin.androidx.viewmodel.ext.android.getSharedViewModel
 
 internal class StorageRootsFragment : Fragment(), StorageRootClickedListener {
 
@@ -42,9 +42,9 @@ internal class StorageRootsFragment : Fragment(), StorageRootClickedListener {
         super.onActivityCreated(savedInstanceState)
 
         viewModel = if (arguments!!.getBoolean(INTENT_EXTRA_IS_RESTORE)) {
-            ViewModelProviders.of(requireActivity()).get(RestoreStorageViewModel::class.java)
+            getSharedViewModel<RestoreStorageViewModel>()
         } else {
-            ViewModelProviders.of(requireActivity()).get(BackupStorageViewModel::class.java)
+            getSharedViewModel<BackupStorageViewModel>()
         }
 
         if (viewModel.isRestoreOperation) {

app/src/main/java/com/stevesoltys/seedvault/ui/storage/StorageViewModel.kt

@@ -12,11 +12,11 @@ import android.util.Log
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
-import com.stevesoltys.seedvault.Backup
 import com.stevesoltys.seedvault.R
 import com.stevesoltys.seedvault.isMassStorage
 import com.stevesoltys.seedvault.settings.BackupManagerSettings
 import com.stevesoltys.seedvault.settings.FlashDrive
+import com.stevesoltys.seedvault.settings.SettingsManager
 import com.stevesoltys.seedvault.settings.Storage
 import com.stevesoltys.seedvault.transport.ConfigurableBackupTransportService
 import com.stevesoltys.seedvault.ui.LiveEvent
@@ -24,9 +24,10 @@ import com.stevesoltys.seedvault.ui.MutableLiveEvent
 
 private val TAG = StorageViewModel::class.java.simpleName
 
-internal abstract class StorageViewModel(private val app: Application) : AndroidViewModel(app), RemovableStorageListener {
+internal abstract class StorageViewModel(
-
+        private val app: Application,
-    protected val settingsManager = (app as Backup).settingsManager
+        protected val settingsManager: SettingsManager
+) : AndroidViewModel(app), RemovableStorageListener {
 
     private val mStorageRoots = MutableLiveData<List<StorageRoot>>()
     internal val storageRoots: LiveData<List<StorageRoot>> get() = mStorageRoots
@@ -44,8 +45,7 @@ internal abstract class StorageViewModel(private val app: Application) : Android
     abstract val isRestoreOperation: Boolean
 
     companion object {
-        internal fun validLocationIsSet(context: Context): Boolean {
+        internal fun validLocationIsSet(context: Context, settingsManager: SettingsManager): Boolean {
-            val settingsManager = (context.applicationContext as Backup).settingsManager
             val storage = settingsManager.getStorage() ?: return false
             if (storage.isUsb) return true
             return storage.getDocumentFile(context).isDirectory

app/src/test/java/com/stevesoltys/seedvault/transport/CoordinatorIntegrationTest.kt

@@ -50,7 +50,7 @@ internal class CoordinatorIntegrationTest : TransportTest() {
     private val kvRestore = KVRestore(kvRestorePlugin, outputFactory, headerReader, cryptoImpl)
     private val fullRestorePlugin = mockk<FullRestorePlugin>()
     private val fullRestore = FullRestore(fullRestorePlugin, outputFactory, headerReader, cryptoImpl)
-    private val restore = RestoreCoordinator(context, settingsManager, restorePlugin, kvRestore, fullRestore, metadataReader)
+    private val restore = RestoreCoordinator(settingsManager, restorePlugin, kvRestore, fullRestore, metadataReader)
 
     private val backupDataInput = mockk<BackupDataInput>()
     private val fileDescriptor = mockk<ParcelFileDescriptor>(relaxed = true)

app/src/test/java/com/stevesoltys/seedvault/transport/restore/RestoreCoordinatorTest.kt

@@ -27,7 +27,7 @@ internal class RestoreCoordinatorTest : TransportTest() {
     private val full = mockk<FullRestore>()
     private val metadataReader = mockk<MetadataReader>()
 
-    private val restore = RestoreCoordinator(context, settingsManager, plugin, kv, full, metadataReader)
+    private val restore = RestoreCoordinator(settingsManager, plugin, kv, full, metadataReader)
 
     private val token = Random.nextLong()
     private val inputStream = mockk<InputStream>()
@@ -43,7 +43,7 @@ internal class RestoreCoordinatorTest : TransportTest() {
                 androidVersion = Random.nextInt(),
                 deviceName = getRandomString())
 
-        every { plugin.getAvailableBackups(context) } returns sequenceOf(encryptedMetadata, encryptedMetadata)
+        every { plugin.getAvailableBackups() } returns sequenceOf(encryptedMetadata, encryptedMetadata)
         every { metadataReader.readMetadata(inputStream, token) } returns metadata
         every { inputStream.close() } just Runs