android: defer taildrop selector until first taildrop attempt

Move Taildrop directory selector out of onboarding
-Listen for Taildrop, and show selector if a directory has not been set

Remove LocalBackend re-initialization
-This is no longer necessary since the directory is set in FileOps

Updates tailscale/corp#29211

Signed-off-by: kari-ts <kari@tailscale.com>

android/src/main/java/com/tailscale/ipn/MainActivity.kt

@@ -48,6 +48,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.core.net.toUri
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
+import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavHostController
 import androidx.navigation.NavType
@@ -94,7 +95,6 @@ import com.tailscale.ipn.ui.view.TailnetLockSetupView
 import com.tailscale.ipn.ui.view.UserSwitcherNav
 import com.tailscale.ipn.ui.view.UserSwitcherView
 import com.tailscale.ipn.ui.viewModel.AppViewModel
-import com.tailscale.ipn.ui.viewModel.AppViewModelFactory
 import com.tailscale.ipn.ui.viewModel.ExitNodePickerNav
 import com.tailscale.ipn.ui.viewModel.MainViewModel
 import com.tailscale.ipn.ui.viewModel.MainViewModelFactory
@@ -112,12 +112,9 @@ import kotlinx.coroutines.launch
 class MainActivity : ComponentActivity() {
   private lateinit var navController: NavHostController
   private lateinit var vpnPermissionLauncher: ActivityResultLauncher<Intent>
-  private val appViewModel: AppViewModel by viewModels {
-    AppViewModelFactory(
-        application = this.application, taildropPrompt = ShareFileHelper.taildropPrompt)
-  }
 
-  private val viewModel: MainViewModel by viewModels { MainViewModelFactory(appViewModel) }
+  private lateinit var appViewModel: AppViewModel
+  private lateinit var viewModel: MainViewModel
 
   val permissionsViewModel: PermissionsViewModel by viewModels()
 
@@ -144,6 +141,11 @@ class MainActivity : ComponentActivity() {
     // grab app to make sure it initializes
     App.get()
 
+    appViewModel = (application as App).getAppScopedViewModel()
+
+    viewModel =
+        ViewModelProvider(this, MainViewModelFactory(appViewModel)).get(MainViewModel::class.java)
+
     val rm = getSystemService(Context.RESTRICTIONS_SERVICE) as RestrictionsManager
     MDMSettings.update(App.get(), rm)
 
@@ -232,6 +234,19 @@ class MainActivity : ComponentActivity() {
 
     appViewModel.directoryPickerLauncher = directoryPickerLauncher
 
+    lifecycleScope.launchWhenStarted {
+      appViewModel.triggerDirectoryPicker.collect {
+        AlertDialog.Builder(this@MainActivity)
+            .setTitle(R.string.taildrop_directory_picker_title)
+            .setMessage(R.string.taildrop_directory_picker_body)
+            .setPositiveButton(R.string.taildrop_directory_picker_button) { _, _ ->
+              appViewModel.directoryPickerLauncher?.launch(null)
+            }
+            .setNegativeButton(android.R.string.cancel, null)
+            .show()
+      }
+    }
+
     setContent {
       var showDialog by remember { mutableStateOf(false) }
 
@@ -242,10 +257,7 @@ class MainActivity : ComponentActivity() {
       if (showDialog) {
         AppTheme {
           AlertDialog(
-              onDismissRequest = {
+              onDismissRequest = { showDialog = false },
-                showDialog = false
-                appViewModel.directoryPickerLauncher?.launch(null)
-              },
               title = {
                 Text(text = stringResource(id = R.string.taildrop_directory_picker_title))
               },

android/src/main/java/com/tailscale/ipn/TaildropDirectoryStore.kt

@@ -16,14 +16,6 @@ object TaildropDirectoryStore {
   fun saveFileDirectory(directoryUri: Uri) {
     val prefs = App.get().getEncryptedPrefs()
     prefs.edit().putString(PREF_KEY_SAF_URI, directoryUri.toString()).commit()
-    try {
-      // Must restart Tailscale because a new LocalBackend with the new directory must be created.
-      App.get().startLibtailscale(directoryUri.toString())
-    } catch (e: Exception) {
-      TSLog.d(
-          "TaildropDirectoryStore",
-          "saveFileDirectory: Failed to restart Libtailscale with the new directory: $e")
-    }
   }
 
   @Throws(IOException::class, GeneralSecurityException::class)

android/src/main/java/com/tailscale/ipn/ui/view/MainView.kt

@@ -70,11 +70,13 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.repeatOnLifecycle
 import com.google.accompanist.permissions.ExperimentalPermissionsApi
+import com.tailscale.ipn.App
 import com.tailscale.ipn.R
 import com.tailscale.ipn.mdm.MDMSettings
 import com.tailscale.ipn.mdm.ShowHide
@@ -109,6 +111,7 @@ import com.tailscale.ipn.ui.viewModel.AppViewModel
 import com.tailscale.ipn.ui.viewModel.IpnViewModel.NodeState
 import com.tailscale.ipn.ui.viewModel.MainViewModel
 import com.tailscale.ipn.util.FeatureFlags
+import kotlinx.coroutines.flow.emptyFlow
 
 // Navigation actions for the MainView
 data class MainViewNavigation(
@@ -131,11 +134,11 @@ fun MainView(
   val healthIcon by viewModel.healthIcon.collectAsState()
   val showDirectoryPicker = appViewModel.showDirectoryPickerInterstitial.collectAsState(null)
 
-    LaunchedEffect(showDirectoryPicker.value) {
+  LaunchedEffect(showDirectoryPicker.value) {
-        if (showDirectoryPicker.value != null) {
+    if (showDirectoryPicker.value != null) {
-            appViewModel.directoryPickerLauncher?.launch(null)
+      appViewModel.directoryPickerLauncher?.launch(null)
-        }
     }
+  }
 
   LoadingIndicator.Wrap {
     Scaffold(contentWindowInsets = WindowInsets.Companion.statusBars) { paddingInsets ->
@@ -221,14 +224,6 @@ fun MainView(
                 LaunchVpnPermissionIfNeeded(viewModel)
                 PromptForMissingPermissions(viewModel)
 
-                if (!viewModel.skipPromptsForAuthKeyLogin()) {
-                  LaunchedEffect(state) {
-                    if (state == Ipn.State.Running && !isAndroidTV()) {
-                      appViewModel.checkIfTaildropDirectorySelected()
-                    }
-                  }
-                }
-
                 if (showKeyExpiry) {
                   ExpiryNotification(netmap = netmap, action = { viewModel.login() })
                 }
@@ -848,11 +843,12 @@ fun Search(
             }
       }
 }
-/*
+
 @Preview
 @Composable
 fun MainViewPreview() {
-  val appViewModel = AppViewModel(App.get())
+  val fakePrompt = emptyFlow<Unit>()
+  val appViewModel = AppViewModel(App.get(), fakePrompt)
   val vm = MainViewModel(appViewModel)
 
   MainView(
@@ -866,4 +862,3 @@ fun MainViewPreview() {
       vm,
       appViewModel)
 }
-*/

android/src/main/java/com/tailscale/ipn/ui/viewModel/AppViewModel.kt

@@ -57,6 +57,8 @@ class AppViewModel(application: Application, private val taildropPrompt: Flow<Un
   var directoryPickerLauncher: ActivityResultLauncher<Uri?>? = null
   private val _showDirectoryPickerInterstitial = MutableSharedFlow<Unit>(extraBufferCapacity = 1)
   val showDirectoryPickerInterstitial: SharedFlow<Unit> = _showDirectoryPickerInterstitial
+  private val _triggerDirectoryPicker = MutableSharedFlow<Unit>(extraBufferCapacity = 1)
+  val triggerDirectoryPicker: SharedFlow<Unit> = _triggerDirectoryPicker
   val TAG = "AppViewModel"
 
   init {
@@ -73,6 +75,10 @@ class AppViewModel(application: Application, private val taildropPrompt: Flow<Un
     }
   }
 
+  fun requestDirectoryPicker() {
+    _triggerDirectoryPicker.tryEmit(Unit)
+  }
+
   private fun prepareVpn() {
     // Check if the user has granted permission yet.
     if (!vpnPrepared.value) {
@@ -99,7 +105,7 @@ class AppViewModel(application: Application, private val taildropPrompt: Flow<Un
       TSLog.d(
           "MainViewModel",
           "Stored directory URI is invalid or inaccessible; launching directory picker.")
-      viewModelScope.launch { _showDirectoryPickerInterstitial.tryEmit(Unit) }
+      viewModelScope.launch { requestDirectoryPicker() }
     } else {
       TSLog.d("MainViewModel", "Using stored directory URI: $storedUri")
     }

android/src/main/java/com/tailscale/ipn/ui/viewModel/MainViewModel.kt

@@ -12,7 +12,6 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.platform.ClipboardManager
 import androidx.compose.ui.text.AnnotatedString
-import androidx.documentfile.provider.DocumentFile
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
@@ -23,7 +22,6 @@ import com.tailscale.ipn.ui.model.Ipn
 import com.tailscale.ipn.ui.model.Ipn.State
 import com.tailscale.ipn.ui.model.Tailcfg
 import com.tailscale.ipn.ui.notifier.Notifier
-import com.tailscale.ipn.ui.util.AndroidTVUtil
 import com.tailscale.ipn.ui.util.PeerCategorizer
 import com.tailscale.ipn.ui.util.PeerSet
 import com.tailscale.ipn.ui.util.TimeUtil
@@ -162,6 +160,10 @@ class MainViewModel(private val appViewModel: AppViewModel) : IpnViewModel() {
           }
     }
 
+    viewModelScope.launch {
+      isVpnActive.collect { active -> TSLog.d("KARI", "🏷️ isVpnActive changed: $active") }
+    }
+
     viewModelScope.launch {
       _searchTerm.debounce(250L).collect { term ->
         // run the search as a background task

android/src/main/java/com/tailscale/ipn/util/ShareFileHelper.kt

@@ -127,6 +127,8 @@ object ShareFileHelper : libtailscale.ShareFileHelper {
 
   @Throws(IOException::class)
   override fun openFileWriter(fileName: String, offset: Long): libtailscale.OutputStream {
+    TSLog.d("ShareFileHelper", "openFileWriter called for $fileName\n" +
+      Throwable().stackTraceToString())
     runBlocking { waitUntilTaildropDirReady() }
     val (uri, stream) = openWriterFD(fileName, offset)
     if (stream == null) {
@@ -218,6 +220,7 @@ object ShareFileHelper : libtailscale.ShareFileHelper {
 
   @Throws(IOException::class)
   override fun deleteFile(uri: String) {
+    runBlocking { waitUntilTaildropDirReady() }
     val ctx = appContext ?: throw IOException("DeleteFile: not initialized")
 
     val uri = Uri.parse(uri)
@@ -283,6 +286,7 @@ object ShareFileHelper : libtailscale.ShareFileHelper {
 
   @Throws(IOException::class)
   override fun openFileReader(name: String): libtailscale.InputStream {
+    runBlocking { waitUntilTaildropDirReady() }
     val context = appContext ?: throw IOException("app context not initialized")
     val rootUri = savedUri ?: throw IOException("SAF URI not initialized")
     val dir =

libtailscale/backend.go

@@ -58,8 +58,6 @@ type App struct {
 	backend         *ipnlocal.LocalBackend
 	ready           sync.WaitGroup
 	backendMu       sync.Mutex
-
-	backendRestartCh chan struct{}
 }
 
 func start(dataDir, directFileRoot string, appCtx AppContext) Application {

libtailscale/tailscale.go

@@ -32,10 +32,9 @@ const (
 
 func newApp(dataDir, directFileRoot string, appCtx AppContext) Application {
 	a := &App{
-		directFileRoot:   directFileRoot,
+		directFileRoot: directFileRoot,
-		dataDir:          dataDir,
+		dataDir:        dataDir,
-		appCtx:           appCtx,
+		appCtx:         appCtx,
-		backendRestartCh: make(chan struct{}, 1),
 	}
 	a.ready.Add(2)