#30 improved obsolete file handling

android/app/src/main/kotlin/deckers/thibault/aves/MainActivity.kt

@@ -13,6 +13,7 @@ import androidx.core.graphics.drawable.IconCompat
 import app.loup.streams_channel.StreamsChannel
 import deckers.thibault.aves.channel.calls.*
 import deckers.thibault.aves.channel.streams.*
+import deckers.thibault.aves.model.provider.MediaStoreImageProvider
 import deckers.thibault.aves.utils.LogUtils
 import deckers.thibault.aves.utils.PermissionManager
 import io.flutter.embedding.android.FlutterActivity
@@ -84,7 +85,8 @@ class MainActivity : FlutterActivity() {
     }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
-        if (requestCode == PermissionManager.VOLUME_ACCESS_REQUEST_CODE) {
+        when (requestCode) {
+            VOLUME_ACCESS_REQUEST -> {
                 val treeUri = data?.data
                 if (resultCode != RESULT_OK || treeUri == null) {
                     PermissionManager.onPermissionResult(requestCode, null)
@@ -100,6 +102,13 @@ class MainActivity : FlutterActivity() {
                 // resume pending action
                 PermissionManager.onPermissionResult(requestCode, treeUri)
             }
+            DELETE_PERMISSION_REQUEST -> {
+                // delete permission may be requested on Android 10+ only
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+                    MediaStoreImageProvider.pendingDeleteCompleter?.complete(resultCode == RESULT_OK)
+                }
+            }
+        }
     }
 
     private fun extractIntentData(intent: Intent?): MutableMap<String, Any?> {
@@ -174,5 +183,7 @@ class MainActivity : FlutterActivity() {
     companion object {
         private val LOG_TAG = LogUtils.createTag<MainActivity>()
         const val VIEWER_CHANNEL = "deckers.thibault/aves/viewer"
+        const val VOLUME_ACCESS_REQUEST = 1
+        const val DELETE_PERMISSION_REQUEST = 2
     }
 }

android/app/src/main/kotlin/deckers/thibault/aves/channel/streams/ImageOpStreamHandler.kt

@@ -1,6 +1,6 @@
 package deckers.thibault.aves.channel.streams
 
-import android.content.Context
+import android.app.Activity
 import android.net.Uri
 import android.os.Handler
 import android.os.Looper
@@ -18,7 +18,7 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
 import java.util.*
 
-class ImageOpStreamHandler(private val context: Context, private val arguments: Any?) : EventChannel.StreamHandler {
+class ImageOpStreamHandler(private val activity: Activity, private val arguments: Any?) : EventChannel.StreamHandler {
     private lateinit var eventSink: EventSink
     private lateinit var handler: Handler
 
@@ -103,7 +103,7 @@ class ImageOpStreamHandler(private val context: Context, private val arguments:
                     "uri" to uri.toString(),
                 )
                 try {
-                    provider.delete(context, uri, path)
+                    provider.delete(activity, uri, path)
                     result["success"] = true
                 } catch (e: Exception) {
                     Log.w(LOG_TAG, "failed to delete entry with path=$path", e)
@@ -138,7 +138,7 @@ class ImageOpStreamHandler(private val context: Context, private val arguments:
 
         destinationDir = StorageUtils.ensureTrailingSeparator(destinationDir)
         val entries = entryMapList.map(::AvesEntry)
-        provider.exportMultiple(context, mimeType, destinationDir, entries, object : ImageOpCallback {
+        provider.exportMultiple(activity, mimeType, destinationDir, entries, object : ImageOpCallback {
             override fun onSuccess(fields: FieldMap) = success(fields)
             override fun onFailure(throwable: Throwable) = error("export-failure", "failed to export entries", throwable)
         })
@@ -168,7 +168,7 @@ class ImageOpStreamHandler(private val context: Context, private val arguments:
 
         destinationDir = StorageUtils.ensureTrailingSeparator(destinationDir)
         val entries = entryMapList.map(::AvesEntry)
-        provider.moveMultiple(context, copy, destinationDir, entries, object : ImageOpCallback {
+        provider.moveMultiple(activity, copy, destinationDir, entries, object : ImageOpCallback {
             override fun onSuccess(fields: FieldMap) = success(fields)
             override fun onFailure(throwable: Throwable) = error("move-failure", "failed to move entries", throwable)
         })

android/app/src/main/kotlin/deckers/thibault/aves/model/provider/ImageProvider.kt

@@ -1,5 +1,6 @@
 package deckers.thibault.aves.model.provider
 
+import android.app.Activity
 import android.content.ContentUris
 import android.content.Context
 import android.graphics.Bitmap
@@ -40,11 +41,11 @@ abstract class ImageProvider {
         callback.onFailure(UnsupportedOperationException())
     }
 
-    open suspend fun delete(context: Context, uri: Uri, path: String?) {
+    open suspend fun delete(activity: Activity, uri: Uri, path: String?) {
         throw UnsupportedOperationException()
     }
 
-    open suspend fun moveMultiple(context: Context, copy: Boolean, destinationDir: String, entries: List<AvesEntry>, callback: ImageOpCallback) {
+    open suspend fun moveMultiple(activity: Activity, copy: Boolean, destinationDir: String, entries: List<AvesEntry>, callback: ImageOpCallback) {
         callback.onFailure(UnsupportedOperationException())
     }
 

android/app/src/main/kotlin/deckers/thibault/aves/model/provider/MediaStoreImageProvider.kt

@@ -1,6 +1,8 @@
 package deckers.thibault.aves.model.provider
 
 import android.annotation.SuppressLint
+import android.app.Activity
+import android.app.RecoverableSecurityException
 import android.content.ContentUris
 import android.content.Context
 import android.net.Uri
@@ -8,6 +10,7 @@ import android.os.Build
 import android.provider.MediaStore
 import android.util.Log
 import com.commonsware.cwac.document.DocumentFileCompat
+import deckers.thibault.aves.MainActivity.Companion.DELETE_PERMISSION_REQUEST
 import deckers.thibault.aves.model.AvesEntry
 import deckers.thibault.aves.model.FieldMap
 import deckers.thibault.aves.model.SourceEntry
@@ -22,6 +25,7 @@ import deckers.thibault.aves.utils.StorageUtils.requireAccessPermission
 import deckers.thibault.aves.utils.UriUtils.tryParseId
 import java.io.File
 import java.util.*
+import java.util.concurrent.CompletableFuture
 import kotlin.collections.ArrayList
 
 class MediaStoreImageProvider : ImageProvider() {
@@ -205,31 +209,55 @@ class MediaStoreImageProvider : ImageProvider() {
     private fun needSize(mimeType: String) = MimeTypes.SVG != mimeType
 
     // `uri` is a media URI, not a document URI
-    override suspend fun delete(context: Context, uri: Uri, path: String?) {
+    override suspend fun delete(activity: Activity, uri: Uri, path: String?) {
         path ?: throw Exception("failed to delete file because path is null")
 
-        if (File(path).exists() && requireAccessPermission(context, path)) {
+        if (File(path).exists() && requireAccessPermission(activity, path)) {
             // if the file is on SD card, calling the content resolver `delete()` removes the entry from the Media Store
             // but it doesn't delete the file, even if the app has the permission
-            val df = getDocumentFile(context, path, uri)
+            val df = getDocumentFile(activity, path, uri)
 
             @Suppress("BlockingMethodInNonBlockingContext")
             if (df != null && df.delete()) return
             throw Exception("failed to delete file with df=$df")
         }
 
-        if (context.contentResolver.delete(uri, null, null) > 0) return
+        try {
+            if (activity.contentResolver.delete(uri, null, null) > 0) return
+        } catch (securityException: SecurityException) {
+            // even if the app has access permission granted on the containing directory,
+            // the delete request may yield a `RecoverableSecurityException` on Android 10+
+            // when the underlying file no longer exists and this is an orphaned entry in the Media Store
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                val rse = securityException as? RecoverableSecurityException ?: throw securityException
+                val intentSender = rse.userAction.actionIntent.intentSender
+
+                // request user permission for this item
+                pendingDeleteCompleter = CompletableFuture<Boolean>()
+                activity.startIntentSenderForResult(intentSender, DELETE_PERMISSION_REQUEST, null, 0, 0, 0, null)
+                val granted = pendingDeleteCompleter!!.join()
+
+                pendingDeleteCompleter = null
+                if (granted) {
+                    delete(activity, uri, path)
+                } else {
+                    throw Exception("failed to get delete permission")
+                }
+            } else {
+                throw securityException
+            }
+        }
         throw Exception("failed to delete row from content provider")
     }
 
     override suspend fun moveMultiple(
-        context: Context,
+        activity: Activity,
         copy: Boolean,
         destinationDir: String,
         entries: List<AvesEntry>,
         callback: ImageOpCallback,
     ) {
-        val destinationDirDocFile = createDirectoryIfAbsent(context, destinationDir)
+        val destinationDirDocFile = createDirectoryIfAbsent(activity, destinationDir)
         if (destinationDirDocFile == null) {
             callback.onFailure(Exception("failed to create directory at path=$destinationDir"))
             return
@@ -262,7 +290,7 @@ class MediaStoreImageProvider : ImageProvider() {
                 // - the Media Store only allows inserting in specific primary directories ("DCIM", "Pictures") when using scoped storage
                 try {
                     val newFields = moveSingleByTreeDocAndScan(
-                        context, sourcePath, sourceUri, destinationDir, destinationDirDocFile, mimeType, copy,
+                        activity, sourcePath, sourceUri, destinationDir, destinationDirDocFile, mimeType, copy,
                     )
                     result["newFields"] = newFields
                     result["success"] = true
@@ -275,7 +303,7 @@ class MediaStoreImageProvider : ImageProvider() {
     }
 
     private suspend fun moveSingleByTreeDocAndScan(
-        context: Context,
+        activity: Activity,
         sourcePath: String,
         sourceUri: Uri,
         destinationDir: String,
@@ -303,12 +331,12 @@ class MediaStoreImageProvider : ImageProvider() {
         // note that `DocumentFile.getParentFile()` returns null if we did not pick a tree first
         @Suppress("BlockingMethodInNonBlockingContext")
         val destinationTreeFile = destinationDirDocFile.createFile(mimeType, desiredNameWithoutExtension)
-        val destinationDocFile = DocumentFileCompat.fromSingleUri(context, destinationTreeFile.uri)
+        val destinationDocFile = DocumentFileCompat.fromSingleUri(activity, destinationTreeFile.uri)
 
         // `DocumentsContract.moveDocument()` needs `sourceParentDocumentUri`, which could be different for each entry
         // `DocumentsContract.copyDocument()` yields "Unsupported call: android:copyDocument"
         // when used with entry URI as `sourceDocumentUri`, and destinationDirDocFile URI as `targetParentDocumentUri`
-        val source = DocumentFileCompat.fromSingleUri(context, sourceUri)
+        val source = DocumentFileCompat.fromSingleUri(activity, sourceUri)
         @Suppress("BlockingMethodInNonBlockingContext")
         source.copyTo(destinationDocFile)
 
@@ -322,14 +350,14 @@ class MediaStoreImageProvider : ImageProvider() {
         if (!copy) {
             // delete original entry
             try {
-                delete(context, sourceUri, sourcePath)
+                delete(activity, sourceUri, sourcePath)
                 deletedSource = true
             } catch (e: Exception) {
                 Log.w(LOG_TAG, "failed to delete entry with path=$sourcePath", e)
             }
         }
 
-        return scanNewPath(context, destinationFullPath, mimeType).apply {
+        return scanNewPath(activity, destinationFullPath, mimeType).apply {
             put("deletedSource", deletedSource)
         }
     }
@@ -366,6 +394,8 @@ class MediaStoreImageProvider : ImageProvider() {
                 MediaStore.MediaColumns.ORIENTATION,
             ) else emptyArray()
         )
+
+        var pendingDeleteCompleter: CompletableFuture<Boolean>? = null
     }
 }
 

android/app/src/main/kotlin/deckers/thibault/aves/utils/PermissionManager.kt

@@ -9,6 +9,7 @@ import android.os.Environment
 import android.os.storage.StorageManager
 import android.util.Log
 import androidx.annotation.RequiresApi
+import deckers.thibault.aves.MainActivity.Companion.VOLUME_ACCESS_REQUEST
 import deckers.thibault.aves.utils.StorageUtils.PathSegments
 import java.io.File
 import java.util.*
@@ -18,8 +19,6 @@ import kotlin.collections.ArrayList
 object PermissionManager {
     private val LOG_TAG = LogUtils.createTag<PermissionManager>()
 
-    const val VOLUME_ACCESS_REQUEST_CODE = 1
-
     // permission request code to pending runnable
     private val pendingPermissionMap = ConcurrentHashMap<Int, PendingPermissionHandler>()
 
@@ -39,8 +38,8 @@ object PermissionManager {
         }
 
         if (intent.resolveActivity(activity.packageManager) != null) {
-            pendingPermissionMap[VOLUME_ACCESS_REQUEST_CODE] = PendingPermissionHandler(path, onGranted, onDenied)
+            pendingPermissionMap[VOLUME_ACCESS_REQUEST] = PendingPermissionHandler(path, onGranted, onDenied)
-            activity.startActivityForResult(intent, VOLUME_ACCESS_REQUEST_CODE, null)
+            activity.startActivityForResult(intent, VOLUME_ACCESS_REQUEST, null)
         } else {
             Log.e(LOG_TAG, "failed to resolve activity for intent=$intent")
             onDenied()

lib/theme/icons.dart

@@ -8,6 +8,7 @@ class AIcons {
   static const IconData vector = Icons.code_outlined;
 
   static const IconData android = Icons.android;
+  static const IconData broken = Icons.broken_image_outlined;
   static const IconData checked = Icons.done_outlined;
   static const IconData date = Icons.calendar_today_outlined;
   static const IconData disc = Icons.fiber_manual_record;

lib/widgets/collection/thumbnail/error.dart

@@ -1,8 +1,13 @@
+import 'dart:io';
+
 import 'package:aves/model/entry.dart';
+import 'package:aves/theme/icons.dart';
 import 'package:aves/utils/mime_utils.dart';
+import 'package:aves/widgets/common/extensions/build_context.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 
-class ErrorThumbnail extends StatelessWidget {
+class ErrorThumbnail extends StatefulWidget {
   final AvesEntry entry;
   final double extent;
   final String tooltip;
@@ -13,23 +18,53 @@ class ErrorThumbnail extends StatelessWidget {
     @required this.tooltip,
   });
 
+  @override
+  _ErrorThumbnailState createState() => _ErrorThumbnailState();
+}
+
+class _ErrorThumbnailState extends State<ErrorThumbnail> {
+  Future<bool> _exists;
+
+  AvesEntry get entry => widget.entry;
+
+  double get extent => widget.extent;
+
+  @override
+  void initState() {
+    super.initState();
+    _exists = entry.path != null ? File(entry.path).exists() : SynchronousFuture(true);
+  }
+
   @override
   Widget build(BuildContext context) {
+    final color = Colors.blueGrey;
+    return FutureBuilder<bool>(
+        future: _exists,
+        builder: (context, snapshot) {
+          if (snapshot.connectionState != ConnectionState.done) return SizedBox();
+          final exists = snapshot.data;
           return Container(
             alignment: Alignment.center,
             color: Colors.black,
             child: Tooltip(
-        message: tooltip,
+              message: exists ? widget.tooltip : context.l10n.viewerErrorDoesNotExist,
               preferBelow: false,
-        child: Text(
+              child: exists
+                  ? Text(
                       MimeUtils.displayType(entry.mimeType),
                       style: TextStyle(
-            color: Colors.blueGrey,
+                        color: color,
                         fontSize: extent / 5,
                       ),
                       textAlign: TextAlign.center,
+                    )
+                  : Icon(
+                      AIcons.broken,
+                      size: extent / 2,
+                      color: color,
                     ),
             ),
           );
+        });
   }
 }

lib/widgets/viewer/visual/error.dart

@@ -45,7 +45,7 @@ class _ErrorViewState extends State<ErrorView> {
               if (snapshot.connectionState != ConnectionState.done) return SizedBox();
               final exists = snapshot.data;
               return EmptyContent(
-                icon: AIcons.error,
+                icon: exists ? AIcons.error : AIcons.broken,
                 text: exists ? context.l10n.viewerErrorUnknown : context.l10n.viewerErrorDoesNotExist,
                 alignment: Alignment.center,
               );