Save restore storage only when it had backups

Incidentally this gets rid of the need to pass an implementation-specific Uri to the StoragePlugin.

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

@@ -74,8 +74,8 @@ class PluginTest : KoinComponent {
     fun testInitializationAndRestoreSets() = runBlocking(Dispatchers.IO) {
         // no backups available initially
         assertEquals(0, storagePlugin.getAvailableBackups()?.toList()?.size)
-        val uri = settingsManager.getStorage()?.getDocumentFile(context)?.uri ?: error("no storage")
-        assertFalse(storagePlugin.hasBackup(uri))
+        val s = settingsManager.getStorage() ?: error("no storage")
+        assertFalse(storagePlugin.hasBackup(s))
 
         // prepare returned tokens requested when initializing device
         every { mockedSettingsManager.getToken() } returnsMany listOf(token, token + 1, token + 1)
@@ -90,7 +90,7 @@ class PluginTest : KoinComponent {
 
         // one backup available now
         assertEquals(1, storagePlugin.getAvailableBackups()?.toList()?.size)
-        assertTrue(storagePlugin.hasBackup(uri))
+        assertTrue(storagePlugin.hasBackup(s))
 
         // initializing again (with another restore set) does add a restore set
         storagePlugin.startNewRestoreSet(token + 1)
@@ -98,7 +98,7 @@ class PluginTest : KoinComponent {
         storagePlugin.getOutputStream(token + 1, FILE_BACKUP_METADATA)
             .writeAndClose(getRandomByteArray())
         assertEquals(2, storagePlugin.getAvailableBackups()?.toList()?.size)
-        assertTrue(storagePlugin.hasBackup(uri))
+        assertTrue(storagePlugin.hasBackup(s))
 
         // initializing again (without new restore set) doesn't change number of restore sets
         storagePlugin.initializeDevice()

app/src/main/java/com/stevesoltys/seedvault/plugins/StoragePlugin.kt

@@ -1,8 +1,8 @@
 package com.stevesoltys.seedvault.plugins
 
 import android.app.backup.RestoreSet
-import android.net.Uri
 import androidx.annotation.WorkerThread
+import com.stevesoltys.seedvault.settings.Storage
 import java.io.IOException
 import java.io.InputStream
 import java.io.OutputStream
@@ -48,14 +48,12 @@ interface StoragePlugin {
     suspend fun removeData(token: Long, name: String)
 
     /**
-     * Searches if there's really a backup available in the given location.
+     * Searches if there's really a backup available in the given storage location.
      * Returns true if at least one was found and false otherwise.
-     *
-     * FIXME: Passing a Uri is too plugin-specific and should be handled differently
      */
     @WorkerThread
     @Throws(IOException::class)
-    suspend fun hasBackup(uri: Uri): Boolean
+    suspend fun hasBackup(storage: Storage): Boolean
 
     /**
      * Get the set of all backups currently available for restore.

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

@@ -2,12 +2,12 @@ package com.stevesoltys.seedvault.plugins.saf
 
 import android.content.Context
 import android.content.pm.PackageManager
-import android.net.Uri
 import android.util.Log
 import androidx.documentfile.provider.DocumentFile
 import com.stevesoltys.seedvault.getSystemContext
 import com.stevesoltys.seedvault.plugins.EncryptedMetadata
 import com.stevesoltys.seedvault.plugins.StoragePlugin
+import com.stevesoltys.seedvault.settings.Storage
 import java.io.FileNotFoundException
 import java.io.IOException
 import java.io.InputStream
@@ -77,10 +77,12 @@ internal class DocumentsProviderStoragePlugin(
     }
 
     @Throws(IOException::class)
-    override suspend 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)
+    override suspend fun hasBackup(storage: Storage): Boolean {
+        // potentially get system user context if needed here
+        val c = appContext.getSystemContext { storage.isUsb }
+        val parent = DocumentFile.fromTreeUri(c, storage.uri) ?: throw AssertionError()
+        val rootDir = parent.findFileBlocking(c, DIRECTORY_ROOT) ?: return false
+        val backupSets = getBackups(c, rootDir)
         return backupSets.isNotEmpty()
     }
 

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

@@ -24,14 +24,15 @@ internal class RestoreStorageViewModel(
 
     override fun onLocationSet(uri: Uri) {
         viewModelScope.launch(Dispatchers.IO) {
-            saveStorage(uri)
+            val storage = createStorage(uri)
             val hasBackup = try {
-                storagePlugin.hasBackup(uri)
+                storagePlugin.hasBackup(storage)
             } catch (e: IOException) {
                 Log.e(TAG, "Error reading URI: $uri", e)
                 false
             }
             if (hasBackup) {
+                saveStorage(storage)
                 mLocationChecked.postEvent(LocationResult())
             } else {
                 Log.w(TAG, "Location was rejected: $uri")

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

@@ -98,13 +98,21 @@ internal abstract class StorageViewModel(
      */
     protected fun saveStorage(uri: Uri): Boolean {
         // store backup storage location in settings
+        val storage = createStorage(uri)
+        return saveStorage(storage)
+    }
+
+    protected fun createStorage(uri: Uri): Storage {
         val root = safOption ?: throw IllegalStateException("no storage root")
         val name = if (root.isInternal()) {
             "${root.title} (${app.getString(R.string.settings_backup_location_internal)})"
         } else {
             root.title
         }
-        val storage = Storage(uri, name, root.isUsb, root.requiresNetwork)
+        return Storage(uri, name, root.isUsb, root.requiresNetwork)
+    }
+
+    protected fun saveStorage(storage: Storage): Boolean {
         settingsManager.setStorage(storage)
 
         if (storage.isUsb) {
@@ -117,7 +125,7 @@ internal abstract class StorageViewModel(
         }
         BackupManagerSettings.resetDefaults(app.contentResolver)
 
-        Log.d(TAG, "New storage location saved: $uri")
+        Log.d(TAG, "New storage location saved: ${storage.uri}")
 
         return storage.isUsb
     }