fix(mobile): cancel share download when dialog is dismissed (#25466)

* fix(mobile): cancel share download when dialog is dismissed

* refactor: centralize temporary file cleanup logic

* refactor: replace `CancellationToken` with `Completer<void>` for asset sharing cancellation

---------

Co-authored-by: cmdpromptcritical <cmdpromptcritical@github.com>

mobile/lib/presentation/widgets/action_buttons/share_action_button.widget.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:io';
 
 import 'package:easy_localization/easy_localization.dart';
@@ -41,16 +42,20 @@ class ShareActionButton extends ConsumerWidget {
       return;
     }
 
+    final cancelCompleter = Completer<void>();
+    const preparingDialog = _SharePreparingDialog();
     await showDialog(
       context: context,
       builder: (BuildContext buildContext) {
-        ref.read(actionProvider.notifier).shareAssets(source, context).then((ActionResult result) {
-          ref.read(multiSelectProvider.notifier).reset();
-
-          if (!context.mounted) {
+        ref.read(actionProvider.notifier).shareAssets(source, context, cancelCompleter: cancelCompleter).then((
+          ActionResult result,
+        ) {
+          if (cancelCompleter.isCompleted || !context.mounted) {
             return;
           }
 
+          ref.read(multiSelectProvider.notifier).reset();
+
           if (!result.success) {
             ImmichToast.show(
               context: context,
@@ -64,11 +69,15 @@ class ShareActionButton extends ConsumerWidget {
         });
 
         // show a loading spinner with a "Preparing" message
-        return const _SharePreparingDialog();
+        return preparingDialog;
       },
       barrierDismissible: false,
       useRootNavigator: false,
-    );
+    ).then((_) {
+      if (!cancelCompleter.isCompleted) {
+        cancelCompleter.complete();
+      }
+    });
   }
 
   @override

mobile/lib/providers/infrastructure/action.provider.dart

@@ -405,11 +405,15 @@ class ActionNotifier extends Notifier<void> {
     }
   }
 
-  Future<ActionResult> shareAssets(ActionSource source, BuildContext context) async {
+  Future<ActionResult> shareAssets(
+    ActionSource source,
+    BuildContext context, {
+    Completer<void>? cancelCompleter,
+  }) async {
     final ids = _getAssets(source).toList(growable: false);
 
     try {
-      await _service.shareAssets(ids, context);
+      await _service.shareAssets(ids, context, cancelCompleter: cancelCompleter);
       return ActionResult(count: ids.length, success: true);
     } catch (error, stack) {
       _logger.severe('Failed to share assets', error, stack);

mobile/lib/repositories/asset_media.repository.dart

@@ -23,7 +23,6 @@ final assetMediaRepositoryProvider = Provider((ref) => AssetMediaRepository(ref.
 
 class AssetMediaRepository {
   final AssetApiRepository _assetApiRepository;
-
   static final Logger _log = Logger("AssetMediaRepository");
 
   const AssetMediaRepository(this._assetApiRepository);
@@ -58,6 +57,7 @@ class AssetMediaRepository {
 
   static asset_entity.Asset? toAsset(AssetEntity? local) {
     if (local == null) return null;
+
     final asset_entity.Asset asset = asset_entity.Asset(
       checksum: "",
       localId: local.id,
@@ -72,19 +72,21 @@ class AssetMediaRepository {
       height: local.height,
       isFavorite: local.isFavorite,
     );
+
     if (asset.fileCreatedAt.year == 1970) {
       asset.fileCreatedAt = asset.fileModifiedAt;
     }
+
     if (local.latitude != null) {
       asset.exifInfo = ExifInfo(latitude: local.latitude, longitude: local.longitude);
     }
+
     asset.local = local;
     return asset;
   }
 
   Future<String?> getOriginalFilename(String id) async {
     final entity = await AssetEntity.fromId(id);
-
     if (entity == null) {
       return null;
     }
@@ -101,12 +103,31 @@ class AssetMediaRepository {
     }
   }
 
+  /// Deletes temporary files in parallel
+  Future<void> _cleanupTempFiles(List<File> tempFiles) async {
+    await Future.wait(
+      tempFiles.map((file) async {
+        try {
+          await file.delete();
+        } catch (e) {
+          _log.warning("Failed to delete temporary file: ${file.path}", e);
+        }
+      }),
+    );
+  }
+
   // TODO: make this more efficient
-  Future<int> shareAssets(List<BaseAsset> assets, BuildContext context) async {
+  Future<int> shareAssets(List<BaseAsset> assets, BuildContext context, {Completer<void>? cancelCompleter}) async {
     final downloadedXFiles = <XFile>[];
     final tempFiles = <File>[];
 
     for (var asset in assets) {
+      if (cancelCompleter != null && cancelCompleter.isCompleted) {
+        // if cancelled, delete any temp files created so far
+        await _cleanupTempFiles(tempFiles);
+        return 0;
+      }
+
       final localId = (asset is LocalAsset)
           ? asset.id
           : asset is RemoteAsset
@@ -146,6 +167,11 @@ class AssetMediaRepository {
       return 0;
     }
 
+    if (cancelCompleter != null && cancelCompleter.isCompleted) {
+      await _cleanupTempFiles(tempFiles);
+      return 0;
+    }
+
     // we dont want to await the share result since the
     // "preparing" dialog will not disappear until
     final size = context.sizeData;
@@ -154,13 +180,7 @@ class AssetMediaRepository {
         downloadedXFiles,
         sharePositionOrigin: Rect.fromPoints(Offset.zero, Offset(size.width / 3, size.height)),
       ).then((result) async {
-        for (var file in tempFiles) {
-          try {
-            await file.delete();
-          } catch (e) {
-            _log.warning("Failed to delete temporary file: ${file.path}", e);
-          }
-        }
+        await _cleanupTempFiles(tempFiles);
       }),
     );
 

mobile/lib/services/action.service.dart

@@ -232,8 +232,8 @@ class ActionService {
     await _assetApiRepository.unStack(stackIds);
   }
 
-  Future<int> shareAssets(List<BaseAsset> assets, BuildContext context) {
-    return _assetMediaRepository.shareAssets(assets, context);
+  Future<int> shareAssets(List<BaseAsset> assets, BuildContext context, {Completer<void>? cancelCompleter}) {
+    return _assetMediaRepository.shareAssets(assets, context, cancelCompleter: cancelCompleter);
   }
 
   Future<List<bool>> downloadAll(List<RemoteAsset> assets) {