native call priority management

lib/main.dart

@@ -1,8 +1,8 @@
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/model/image_file_service.dart';
 import 'package:aves/model/settings.dart';
+import 'package:aves/services/image_file_service.dart';
+import 'package:aves/services/viewer_service.dart';
 import 'package:aves/utils/android_file_utils.dart';
-import 'package:aves/utils/viewer_service.dart';
 import 'package:aves/widgets/album/collection_page.dart';
 import 'package:aves/widgets/common/data_providers/media_store_collection_provider.dart';
 import 'package:aves/widgets/fullscreen/fullscreen_page.dart';

lib/model/image_entry.dart

@@ -1,7 +1,8 @@
 import 'package:aves/model/favourite_repo.dart';
-import 'package:aves/model/image_file_service.dart';
 import 'package:aves/model/image_metadata.dart';
-import 'package:aves/model/metadata_service.dart';
+import 'package:aves/services/image_file_service.dart';
+import 'package:aves/services/metadata_service.dart';
+import 'package:aves/services/service_policy.dart';
 import 'package:aves/utils/change_notifier.dart';
 import 'package:aves/utils/time_utils.dart';
 import 'package:flutter/foundation.dart';
@@ -220,7 +221,11 @@ class ImageEntry {
 
     final coordinates = Coordinates(latitude, longitude);
     try {
-      final addresses = await Geocoder.local.findAddressesFromCoordinates(coordinates);
+      final addresses = await servicePolicy.call(
+        () => Geocoder.local.findAddressesFromCoordinates(coordinates),
+        ServiceCallPriority.background,
+        'findAddressesFromCoordinates-$path',
+      );
       if (addresses != null && addresses.isNotEmpty) {
         final address = addresses.first;
         addressDetails = AddressDetails(

lib/services/image_file_service.dart

@@ -1,6 +1,7 @@
 import 'dart:typed_data';
 
 import 'package:aves/model/image_entry.dart';
+import 'package:aves/services/service_policy.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
@@ -42,21 +43,27 @@ class ImageFileService {
     return Uint8List(0);
   }
 
-  static Future<Uint8List> getThumbnail(ImageEntry entry, int width, int height) async {
+  static Future<Uint8List> getThumbnail(ImageEntry entry, int width, int height) {
-    if (width > 0 && height > 0) {
+    return servicePolicy.call(
+      () async {
+        if (width > 0 && height > 0) {
 //      debugPrint('getThumbnail width=$width path=${entry.path}');
-      try {
+          try {
-        final result = await platform.invokeMethod('getThumbnail', <String, dynamic>{
+            final result = await platform.invokeMethod('getThumbnail', <String, dynamic>{
-          'entry': entry.toMap(),
+              'entry': entry.toMap(),
-          'width': width,
+              'width': width,
-          'height': height,
+              'height': height,
-        });
+            });
-        return result as Uint8List;
+            return result as Uint8List;
-      } on PlatformException catch (e) {
+          } on PlatformException catch (e) {
-        debugPrint('getThumbnail failed with code=${e.code}, exception=${e.message}, details=${e.details}');
+            debugPrint('getThumbnail failed with code=${e.code}, exception=${e.message}, details=${e.details}');
-      }
+          }
-    }
+        }
-    return Uint8List(0);
+        return Uint8List(0);
+      },
+      ServiceCallPriority.asapLifo,
+      'getThumbnail-${entry.path}',
+    );
   }
 
   static Future<void> cancelGetThumbnail(String uri) async {

lib/services/metadata_service.dart

@@ -1,5 +1,6 @@
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/image_metadata.dart';
+import 'package:aves/services/service_policy.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
@@ -26,26 +27,32 @@ class MetadataService {
   static Future<CatalogMetadata> getCatalogMetadata(ImageEntry entry) async {
     if (entry.isSvg) return null;
 
-    try {
+    return servicePolicy.call(
-      // return map with:
+      () async {
-      // 'dateMillis': date taken in milliseconds since Epoch (long)
+        try {
-      // 'isAnimated': animated gif/webp (bool)
+          // return map with:
-      // 'latitude': latitude (double)
+          // 'dateMillis': date taken in milliseconds since Epoch (long)
-      // 'longitude': longitude (double)
+          // 'isAnimated': animated gif/webp (bool)
-      // 'videoRotation': video rotation degrees (int)
+          // 'latitude': latitude (double)
-      // 'xmpSubjects': ';' separated XMP subjects (string)
+          // 'longitude': longitude (double)
-      // 'xmpTitleDescription': XMP title or XMP description (string)
+          // 'videoRotation': video rotation degrees (int)
-      final result = await platform.invokeMethod('getCatalogMetadata', <String, dynamic>{
+          // 'xmpSubjects': ';' separated XMP subjects (string)
-        'mimeType': entry.mimeType,
+          // 'xmpTitleDescription': XMP title or XMP description (string)
-        'path': entry.path,
+          final result = await platform.invokeMethod('getCatalogMetadata', <String, dynamic>{
-        'uri': entry.uri,
+            'mimeType': entry.mimeType,
-      }) as Map;
+            'path': entry.path,
-      result['contentId'] = entry.contentId;
+            'uri': entry.uri,
-      return CatalogMetadata.fromMap(result);
+          }) as Map;
-    } on PlatformException catch (e) {
+          result['contentId'] = entry.contentId;
-      debugPrint('getCatalogMetadata failed with code=${e.code}, exception=${e.message}, details=${e.details}');
+          return CatalogMetadata.fromMap(result);
-    }
+        } on PlatformException catch (e) {
-    return null;
+          debugPrint('getCatalogMetadata failed with code=${e.code}, exception=${e.message}, details=${e.details}');
+        }
+        return null;
+      },
+      ServiceCallPriority.background,
+      'getCatalogMetadata-${entry.path}',
+    );
   }
 
   static Future<OverlayMetadata> getOverlayMetadata(ImageEntry entry) async {

lib/services/service_policy.dart

@@ -0,0 +1,58 @@
+import 'dart:async';
+import 'dart:collection';
+
+import 'package:flutter/cupertino.dart';
+
+final ServicePolicy servicePolicy = ServicePolicy._private();
+
+class ServicePolicy {
+  final Queue<VoidCallback> _asapQueue = Queue(), _normalQueue = Queue(), _backgroundQueue = Queue();
+  VoidCallback _running;
+
+  ServicePolicy._private();
+
+  Future<T> call<T>(Future<T> Function() platformCall, [ServiceCallPriority priority = ServiceCallPriority.normal, String debugLabel]) {
+    Queue<VoidCallback> q;
+    switch (priority) {
+      case ServiceCallPriority.asapFifo:
+        q = _asapQueue;
+        break;
+      case ServiceCallPriority.asapLifo:
+        q = _asapQueue;
+        break;
+      case ServiceCallPriority.background:
+        q = _backgroundQueue;
+        break;
+      case ServiceCallPriority.normal:
+      default:
+        q = _normalQueue;
+        break;
+    }
+    final completer = Completer<T>();
+    final wrapped = () async {
+//      if (debugLabel != null) debugPrint('$runtimeType $debugLabel start');
+      final result = await platformCall();
+      completer.complete(result);
+//      if (debugLabel != null) debugPrint('$runtimeType $debugLabel completed');
+      _running = null;
+      _pickNext();
+    };
+    if (priority == ServiceCallPriority.asapLifo) {
+      q.addFirst(wrapped);
+    } else {
+      q.addLast(wrapped);
+    }
+
+    _pickNext();
+    return completer.future;
+  }
+
+  void _pickNext() {
+    if (_running != null) return;
+    final queue = [_asapQueue, _normalQueue, _backgroundQueue].firstWhere((q) => q.isNotEmpty, orElse: () => null);
+    _running = queue?.removeFirst();
+    _running?.call();
+  }
+}
+
+enum ServiceCallPriority { asapFifo, asapLifo, normal, background }

lib/utils/android_file_utils.dart

@@ -1,5 +1,5 @@
-import 'package:aves/utils/android_app_service.dart';
+import 'package:aves/services/android_app_service.dart';
-import 'package:aves/utils/android_file_service.dart';
+import 'package:aves/services/android_file_service.dart';
 import 'package:path/path.dart';
 
 final AndroidFileUtils androidFileUtils = AndroidFileUtils._private();

lib/widgets/album/grid/list_section_layout.dart

@@ -4,6 +4,7 @@ import 'package:aves/model/collection_lens.dart';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/widgets/album/grid/header_generic.dart';
 import 'package:aves/widgets/album/grid/list_sliver.dart';
+import 'package:aves/widgets/album/grid/tile_extent_manager.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
@@ -19,7 +20,7 @@ class SectionedListLayoutProvider extends StatelessWidget {
     @required this.scrollableWidth,
     @required this.tileExtent,
     @required this.child,
-  }) : columnCount = (scrollableWidth / tileExtent).round();
+  }) : columnCount = max((scrollableWidth / tileExtent).round(), TileExtentManager.columnCountMin);
 
   @override
   Widget build(BuildContext context) {

lib/widgets/album/grid/tile_extent_manager.dart

@@ -7,8 +7,12 @@ class TileExtentManager {
   static const int columnCountMin = 2;
   static const int columnCountDefault = 4;
   static const double tileExtentMin = 46.0;
+  static const screenDimensionMin = tileExtentMin * columnCountMin;
 
   static double applyTileExtent(Size mqSize, double mqHorizontalPadding, ValueNotifier<double> extentNotifier, {double newExtent}) {
+    // sanitize screen size (useful when reloading while screen is off, reporting a 0,0 size)
+    mqSize = Size(max(mqSize.width, screenDimensionMin), max(mqSize.height, screenDimensionMin));
+
     final availableWidth = mqSize.width - mqHorizontalPadding;
     var numColumns;
     if ((newExtent ?? 0) == 0) {

lib/widgets/common/data_providers/media_store_collection_provider.dart

@@ -4,9 +4,9 @@ import 'package:aves/model/collection_lens.dart';
 import 'package:aves/model/collection_source.dart';
 import 'package:aves/model/favourite_repo.dart';
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/model/image_file_service.dart';
 import 'package:aves/model/metadata_db.dart';
 import 'package:aves/model/settings.dart';
+import 'package:aves/services/image_file_service.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_native_timezone/flutter_native_timezone.dart';

lib/widgets/common/image_providers/app_icon_image_provider.dart

@@ -1,6 +1,6 @@
 import 'dart:ui' as ui show Codec;
 
-import 'package:aves/utils/android_app_service.dart';
+import 'package:aves/services/android_app_service.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 

lib/widgets/common/image_providers/thumbnail_provider.dart

@@ -1,7 +1,7 @@
 import 'dart:ui' as ui show Codec;
 
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/model/image_file_service.dart';
+import 'package:aves/services/image_file_service.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 

lib/widgets/common/image_providers/uri_image_provider.dart

@@ -1,6 +1,6 @@
 import 'dart:ui' as ui show Codec;
 
-import 'package:aves/model/image_file_service.dart';
+import 'package:aves/services/image_file_service.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 

lib/widgets/common/image_providers/uri_picture_provider.dart

@@ -1,4 +1,4 @@
-import 'package:aves/model/image_file_service.dart';
+import 'package:aves/services/image_file_service.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';

lib/widgets/fullscreen/fullscreen_action_delegate.dart

@@ -2,8 +2,8 @@ import 'dart:io';
 
 import 'package:aves/model/collection_lens.dart';
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/model/image_file_service.dart';
+import 'package:aves/services/android_app_service.dart';
-import 'package:aves/utils/android_app_service.dart';
+import 'package:aves/services/image_file_service.dart';
 import 'package:aves/widgets/common/image_providers/uri_image_provider.dart';
 import 'package:aves/widgets/fullscreen/debug.dart';
 import 'package:aves/widgets/fullscreen/fullscreen_actions.dart';

lib/widgets/fullscreen/info/location_section.dart

@@ -2,7 +2,7 @@ import 'package:aves/model/collection_lens.dart';
 import 'package:aves/model/filters/location.dart';
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/settings.dart';
-import 'package:aves/utils/android_app_service.dart';
+import 'package:aves/services/android_app_service.dart';
 import 'package:aves/utils/geo_utils.dart';
 import 'package:aves/widgets/common/aves_filter_chip.dart';
 import 'package:aves/widgets/common/icons.dart';

lib/widgets/fullscreen/info/metadata_section.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 import 'dart:collection';
 
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/model/metadata_service.dart';
+import 'package:aves/services/metadata_service.dart';
 import 'package:aves/utils/color_utils.dart';
 import 'package:aves/widgets/common/fx/highlight_decoration.dart';
 import 'package:aves/widgets/fullscreen/info/info_page.dart';

lib/widgets/fullscreen/overlay/bottom.dart

@@ -3,7 +3,7 @@ import 'dart:ui';
 
 import 'package:aves/model/image_entry.dart';
 import 'package:aves/model/image_metadata.dart';
-import 'package:aves/model/metadata_service.dart';
+import 'package:aves/services/metadata_service.dart';
 import 'package:aves/utils/constants.dart';
 import 'package:aves/utils/geo_utils.dart';
 import 'package:aves/widgets/common/fx/blurred.dart';

lib/widgets/fullscreen/overlay/video.dart

@@ -1,5 +1,5 @@
 import 'package:aves/model/image_entry.dart';
-import 'package:aves/utils/android_app_service.dart';
+import 'package:aves/services/android_app_service.dart';
 import 'package:aves/utils/time_utils.dart';
 import 'package:aves/widgets/common/fx/blurred.dart';
 import 'package:aves/widgets/fullscreen/overlay/common.dart';