immich/mobile/lib/infrastructure/loaders/image_request.dart

import 'dart:async';
import 'dart:ffi';
import 'dart:io';
import 'dart:ui' as ui;

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter/foundation.dart';
import 'package:ffi/ffi.dart';
import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
import 'package:immich_mobile/providers/image/cache/remote_image_cache_manager.dart';
import 'package:immich_mobile/providers/infrastructure/platform.provider.dart';
import 'package:logging/logging.dart';

part 'local_image_request.dart';
part 'thumbhash_image_request.dart';
part 'remote_image_request.dart';

abstract class ImageRequest {
  static int _nextRequestId = 0;

  final int requestId = _nextRequestId++;
  bool _isCancelled = false;

  get isCancelled => _isCancelled;

  ImageRequest();

  Future<ImageInfo?> load(ImageDecoderCallback decode, {double scale = 1.0});

  void cancel() {
    if (_isCancelled) {
      return;
    }
    _isCancelled = true;
    return _onCancelled();
  }

  void _onCancelled();

  Future<ui.FrameInfo?> _fromPlatformImage(Map<String, int> info) async {
    final address = info['pointer'];
    if (address == null) {
      if (!kReleaseMode) {
        debugPrint('Platform image request for $requestId was cancelled');
      }
      return null;
    }

    final pointer = Pointer<Uint8>.fromAddress(address);
    try {
      if (_isCancelled) {
        return null;
      }

      final actualWidth = info['width']!;
      final actualHeight = info['height']!;
      final actualSize = actualWidth * actualHeight * 4;

      final buffer = await ImmutableBuffer.fromUint8List(pointer.asTypedList(actualSize));
      if (_isCancelled) {
        return null;
      }

      final descriptor = ui.ImageDescriptor.raw(
        buffer,
        width: actualWidth,
        height: actualHeight,
        pixelFormat: ui.PixelFormat.rgba8888,
      );
      final codec = await descriptor.instantiateCodec();
      if (_isCancelled) {
        return null;
      }

      return await codec.getNextFrame();
    } finally {
      malloc.free(pointer);
    }
  }
}