fis_lib_vid/lib/async_vid/vid_data.dart

import 'dart:typed_data';

import 'package:flutter/foundation.dart';
import 'package:vid/us/vid_us_data_http_reader.dart';
import 'package:vid/us/vid_us_data_reader.dart';
import 'package:vid/us/vid_us_image.dart';
import 'package:vid/us/vid_us_image_data.dart';
import 'package:vid/us/vid_us_probe.dart';

import 'reader.dart';

abstract class AsyncVidImageDataBase {
  late AsyncVidDataReaderBase _reader;
  late List<int> _imagePositionList;
  late int _version;
  late int _imageCount;
  late VidUsProbe _probe;
  late VidUsImageFormat _imageFormat;
  late Uint8List _extendedData;
  late int _readHeaderTimeout;
  late int _readImageTimeout;
  late bool _initialized;
  late bool _closed;

  final Duration delayDuration = const Duration(milliseconds: 10);
  final String header = "VINNO IMAGE DATA";

  /// Gets the version of this image data.
  int get version => _version;

  /// Gets the image count of this image data.
  int get imageCount => _imageCount;

  /// Gets the probe information.
  VidUsProbe get probe => _probe;

  /// Gets the image format of this image data.
  VidUsImageFormat get imageFormat => _imageFormat;

  /// Gets the extended data.
  Uint8List get extendedData => _extendedData;

  /// Gets the initialized state.
  bool get initialized => _initialized;

  /// Create a VINNO Image Data.
  /// [readHeaderTimeout] is the timeout value of reading header and probe information etc..., we need give as much time as possible
  /// to let the reader read the header.
  /// [readImageTimeout] is the timeout value of reading one frame.
  /// [minChunkSize] The min download chunk size, set to a large value may speedup the download speed, but will cause the progress not smooth.
  AsyncVidImageDataBase(String url, {DownloadCallback? downloadCallback}) {
    _initialized = false;
    _closed = false;
    createReader(url, downloadCallback: downloadCallback);
  }

  @protected
  AsyncVidDataReaderBase createReader(String url,
      {DownloadCallback? downloadCallback});

  ///Get the downloaded data of this HttpVidUsImageData
  Uint8List getDownloadedData() {
    return _reader.toBytes();
  }

  ///Initialize the HttpVidUsImageData, must be called firstly.
  Future initialize() async {
    if (!_initialized) {
      var header = await _readHeader();
      if (header != header) {
        throw Exception("The input data is not a VID data.");
      }
      _version = await _readVersion();
      //Get probe info
      _probe = await _readProbe();
      _imageFormat = await _readImageFormat();
      _extendedData = await _readExtendedData();
      _imagePositionList = [];
      var imagePositionListData = await _readImagePositionListData();
      _imageCount = imagePositionListData.length ~/ 8;
      var imagePositionReader = VidUsDataReader(imagePositionListData);
      for (var i = 0; i < _imageCount; i++) {
        _imagePositionList.add(imagePositionReader.readInt64V2());
      }
      _initialized = true;
    }
  }

  ///Close the HttpVidUsImageData, it will force close the download operation and reading operation.
  void close() {
    _closed = true;
    _reader.close();
  }

  @protected
  T getReader<T extends AsyncVidDataReaderBase>() => _reader as T;

  ///Read header from http data.
  Future<String> _readHeader() async {
    var timeout = 0;
    while (!_closed) {
      try {
        var header = _reader.readString();
        return header;
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  ///Read the version from http data.
  Future<int> _readVersion() async {
    var timeout = 0;
    while (!_closed) {
      try {
        var version = _reader.readInt();
        return version;
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  ///Read the probe info from http data.
  Future<VidUsProbe> _readProbe() async {
    var timeout = 0;
    while (!_closed) {
      try {
        var probeData = _reader.readBytes();
        return VidUsProbe.fromBytes(probeData);
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  ///Read the image format from http data.
  Future<VidUsImageFormat> _readImageFormat() async {
    var timeout = 0;
    while (!_closed) {
      try {
        return VidUsImageFormat.values[_reader.readInt()];
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  ///Read extended data from http data.
  Future<Uint8List> _readExtendedData() async {
    var timeout = 0;
    while (!_closed) {
      try {
        return _reader.readBytes();
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  ///Read the image positions data from http data.
  Future<Uint8List> _readImagePositionListData() async {
    var timeout = 0;
    while (!_closed) {
      try {
        return _reader.readBytes();
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readHeaderTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }

  /// Get one image from the vid.
  Future<VidUsImage> getImage(int index) async {
    if (index >= _imageCount || index < 0) {
      throw Exception("Can not find image Data");
    }
    //Jump to image.
    var timeout = 0;
    while (!_closed) {
      try {
        var imageData = _reader.readBytes(_imagePositionList[index]);
        return VidUsImage.fromBytes(imageData);
      } catch (ex) {
        if (ex is NotReadyException) {
          if (timeout >= _readImageTimeout) {
            throw ReadTimeoutException();
          }
          await Future.delayed(delayDuration);
          timeout += delayDuration.inMilliseconds;
        } else {
          rethrow;
        }
      }
    }
    throw AlreadyClosedException();
  }
}