fix: too eager caching of images (#314)

The fix is to compute the hashsum of the image data and send it to
Flutter. On the other side, the image data is now always tagged with its
hashsum in the image memory cache.

Author: boxdot

Cargo.lock

@@ -40,7 +40,6 @@ class GroupDetails extends StatelessWidget {
                 size: 64,
                 image: conversation.attributes.picture,
                 username: conversation.username,
-                cacheTag: conversation.avatarCacheTag,
                 onPressed: () async {
                   final conversationDetailsCubit =
                       context.read<ConversationDetailsCubit>();

app/lib/conversation_details/group_details.dart

@@ -88,7 +88,6 @@ class _ListTile extends StatelessWidget {
           children: [
             UserAvatar(
               size: 48,
-              cacheTag: conversation.avatarCacheTag,
               image: conversation.attributes.picture,
               username: conversation.username,
             ),

app/lib/conversation_list/conversation_list_content.dart

@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
+import 'dart:typed_data';
+
 import 'package:prototype/core/core.dart';
 
 extension UiConversationDetailsExtension on UiConversationDetails {
@@ -18,8 +20,6 @@ extension UiConversationDetailsExtension on UiConversationDetails {
         UiConversationType_Connection(field0: final e) => e,
         UiConversationType_Group() => attributes.title,
       };
-
-  String get avatarCacheTag => 'conv:$id:${attributes.picture?.hashCode}';
 }
 
 extension UiConversationTypeExtension on UiConversationType {
@@ -43,3 +43,8 @@ extension UiFlightPositionExtension on UiFlightPosition {
         UiFlightPosition.single || UiFlightPosition.end => true,
       };
 }
+
+extension ImageDataExtension on Uint8List {
+  ImageData toImageData() =>
+      ImageData(data: this, hash: ImageData.computeHash(this));
+}

app/lib/core/core_extension.dart

@@ -4,6 +4,7 @@
 
 import 'package:flutter/material.dart';
 import 'package:image_picker/image_picker.dart';
+import 'package:prototype/core/core.dart';
 import 'package:prototype/main.dart';
 import 'package:prototype/navigation/navigation.dart';
 import 'package:prototype/theme/theme.dart';
@@ -99,7 +100,7 @@ class _UserAvatarPicker extends StatelessWidget {
         final XFile? image =
             await picker.pickImage(source: ImageSource.gallery);
         final bytes = await image?.readAsBytes();
-        registrationCubit.setAvatar(bytes);
+        registrationCubit.setAvatar(bytes?.toImageData());
       },
     );
   }

app/lib/registration/display_name_picture.dart

@@ -2,8 +2,6 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-import 'dart:typed_data';
-
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 import 'package:logging/logging.dart';
@@ -36,7 +34,7 @@ sealed class RegistrationState with _$RegistrationState {
     @Default(false) bool isPasswordValid,
 
     // Display name/avatar screen data
-    Uint8List? avatar,
+    ImageData? avatar,
     String? displayName,
     @Default(false) bool isSigningUp,
   }) = _RegistrationState;
@@ -74,7 +72,7 @@ class RegistrationCubit extends Cubit<RegistrationState> {
     ));
   }
 
-  void setAvatar(Uint8List? bytes) {
+  void setAvatar(ImageData? bytes) {
     emit(state.copyWith(avatar: bytes));
   }
 
@@ -86,7 +84,9 @@ class RegistrationCubit extends Cubit<RegistrationState> {
     emit(state.copyWith(isSigningUp: true));
 
     final fqun = "${state.username}@${state.domain}";
-    final url = "https://${state.domain}";
+    final url = state.domain == "localhost"
+        ? "http://${state.domain}"
+        : "https://${state.domain}";
 
     try {
       _log.info("Registering user ${state.username} ...");
@@ -95,7 +95,7 @@ class RegistrationCubit extends Cubit<RegistrationState> {
         state.password,
         url,
         state.displayName,
-        state.avatar,
+        state.avatar?.data,
       );
     } catch (e) {
       final message = "Error when registering user: ${e.toString()}";

app/lib/registration/registration_cubit.dart

@@ -2,10 +2,9 @@
 //
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-import 'dart:typed_data';
-
 import 'package:flutter/material.dart';
 import 'package:image_picker/image_picker.dart';
+import 'package:prototype/core/core.dart';
 import 'package:prototype/main.dart';
 import 'package:prototype/theme/theme.dart';
 import 'package:prototype/user/user.dart';
@@ -21,7 +20,7 @@ class UserSettingsScreen extends StatefulWidget {
 
 class _UserSettingsScreenState extends State<UserSettingsScreen> {
   String? newDisplayName;
-  Uint8List? newProfilePicture;
+  ImageData? newProfilePicture;
 
   bool get _isChanged => newDisplayName != null || newProfilePicture != null;
 
@@ -30,7 +29,9 @@ class _UserSettingsScreenState extends State<UserSettingsScreen> {
     final messenger = ScaffoldMessenger.of(context);
     try {
       await user.setProfile(
-          displayName: newDisplayName, profilePicture: newProfilePicture);
+        displayName: newDisplayName,
+        profilePicture: newProfilePicture?.data,
+      );
       setState(() {
         newDisplayName = null;
         newProfilePicture = null;
@@ -73,8 +74,9 @@ class _UserSettingsScreenState extends State<UserSettingsScreen> {
                     final XFile? image =
                         await picker.pickImage(source: ImageSource.gallery);
                     final bytes = await image?.readAsBytes();
+                    final data = bytes?.toImageData();
                     setState(() {
-                      newProfilePicture = bytes;
+                      newProfilePicture = data;
                     });
                   },
                 ),

app/lib/user/user_settings_screen.dart

@@ -6,6 +6,7 @@ import 'dart:ui' as ui;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/painting.dart';
+import 'package:prototype/core/core.dart';
 
 /// Same as [MemoryImage] but caches the result in memory under the given [tag]
 class CachedMemoryImage extends ImageProvider<CachedMemoryImage> {
@@ -14,6 +15,9 @@ class CachedMemoryImage extends ImageProvider<CachedMemoryImage> {
     this.bytes,
   );
 
+  factory CachedMemoryImage.fromImageData(ImageData imageData) =>
+      CachedMemoryImage(imageData.hash, imageData.data);
+
   final String tag;
   final Uint8List bytes;
 

app/lib/util/cached_memory_image.dart

@@ -15,14 +15,12 @@ class UserAvatar extends StatelessWidget {
     this.size = 24.0,
     this.image,
     this.onPressed,
-    this.cacheTag,
   });
 
   final String username;
   final double size;
-  final Uint8List? image;
+  final ImageData? image;
   final VoidCallback? onPressed;
-  final String? cacheTag;
 
   @override
   Widget build(BuildContext context) {
@@ -38,9 +36,8 @@ class UserAvatar extends StatelessWidget {
           child: CircleAvatar(
             radius: size / 2,
             backgroundColor: colorDMBLight,
-            foregroundImage: (image != null)
-                ? CachedMemoryImage(cacheTag ?? "avatar:$username", image!)
-                : null,
+            foregroundImage:
+                image != null ? CachedMemoryImage.fromImageData(image!) : null,
             child: Text(
               username.characters.firstOrNull?.toUpperCase() ?? "",
               style: TextStyle(
@@ -92,7 +89,6 @@ class _FutureUserAvatarState extends State<FutureUserAvatar> {
         image: snapshot.data?.profilePicture,
         size: widget.size,
         onPressed: widget.onPressed,
-        cacheTag: widget.cacheTag,
       ),
     );
   }

app/lib/widgets/user_avatar.dart

@@ -26,11 +26,11 @@ class MockUiUser implements UiUser {
     Uint8List? profilePicture,
   })  : _userName = userName,
         _displayName = displayName,
-        _profilePicture = profilePicture;
+        _profilePicture = profilePicture?.toImageData();
 
   final String _userName;
   final String? _displayName;
-  final Uint8List? _profilePicture;
+  final ImageData? _profilePicture;
 
   @override
   String? get displayName => _displayName;
@@ -42,7 +42,7 @@ class MockUiUser implements UiUser {
   bool get isDisposed => false;
 
   @override
-  Uint8List? get profilePicture => _profilePicture;
+  ImageData? get profilePicture => _profilePicture;
 
   @override
   String get userName => _userName;

app/test/mocks.dart

@@ -21,13 +21,14 @@ crate-type = ["cdylib", "staticlib", "lib"]
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(frb_expand)'] }
 
 [dependencies]
+phnxcoreclient = { path = "../coreclient" }
+phnxapiclient = { path = "../apiclient" }
+phnxtypes = { path = "../types" }
+
 tracing = "0.1"
 tracing-subscriber = { workspace = true }
 parking_lot = "0.12"
 uuid = { version = "1", features = ["v4"] }
-phnxcoreclient = { path = "../coreclient" }
-phnxapiclient = { path = "../apiclient" }
-phnxtypes = { path = "../types" }
 anyhow = { version = "1", features = ["backtrace"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
@@ -36,7 +37,6 @@ flutter_rust_bridge = { version = "=2.7.0", features = ["chrono", "uuid"] }
 notify-rust = "4"
 chrono = { workspace = true }
 jni = "0.21"
-
-# Workspace dependencies
 tokio-util = "0.7.13"
 tokio-stream = "0.1.17"
+blake3 = "1.5.5"