fis_lib_vid/lib/data_channel/channel.dart

import 'dart:async';

import 'package:fis_common/event/event_type.dart';
import 'package:fis_common/index.dart';
import 'package:fis_vid/async_vid/vid_data.dart';
import 'package:flutter/foundation.dart';
import 'package:vid/us/vid_us_data_http_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 'channel_stub.dart'
    if (dart.library.html) 'channel_web.dart'
    if (dart.library.io) 'channel_io.dart';

import 'progress_info.dart';

abstract class VidDataChannel {
  @protected
  AsyncVidImageDataBase? source;
  bool get _isVrdPlayer => url.endsWith(".0");

  final String url;

  VidDataChannel(this.url);

  factory VidDataChannel.create(String url) {
    return VidDataChannelImpl(url);
  }

  static void receiveChunk(String id, Uint8List chunk) {
    VidDataChannelImpl.receiveChunk(id, chunk);
  }

  /// 下载进度变更事件
  final downloadProgressChanged = FEventHandler<VidDownloadProgressInfo>();

  bool _initialized = false;

  /// 是否初始化完成
  bool get initialized => _initialized;

  /// 开始加载数据
  ///
  /// [timeout] 超时时间，单位ms, 默认5s
  Future<bool> load([int timeout = 5 * 1000]) async {
    if (_initialized) return true;

    try {
      _initialized = await _innerLoad(timeout);
    } catch (e) {}
    return _initialized;
  }

  /// 分发下载进度回调
  @protected
  void onDownloadCallback(double progress, DownloadErrorException? error) {
    final info = VidDownloadProgressInfo(progress, error: error);
    downloadProgressChanged.emit(this, info);
  }

  Future<bool> _innerLoad(int timeout) async {
    try {
      source = await buildSource();
      source!.setReadHeaderTimeout(timeout + 50); // 50ms buffer 4 timer
      await source!.initialize();
      print("_innerLoad initialize end");
      return true;
    } catch (e) {
      return false;
    }
  }

  ///获取缓冲量
  int getBufferSize() {
    return source!.getReader().downloadedSize;
  }

  /// 获取文件尺寸
  int getFileSize() {
    return source!.getReader().totalSize;
  }

  /// 是否缓冲完成
  bool get isBufferedDone {
    var bufferSize = getBufferSize();
    var fileSized = getFileSize();
    var result = bufferSize >= fileSized;
    print("是否缓冲完成:$result $bufferSize $fileSized");
    return result;
  }

  VidUsProbe get probe => source!.probe;
  int get imageCount => source!.imageCount;
  VidUsImageFormat get imageFormat => source!.imageFormat;
  Uint8List get extendedData => source!.extendedData;

  /// 获取指定帧
  ///
  /// [index] 帧索引
  ///
  /// [timeout] 超时时间ms
  Future<VidUsImage> getImage(int index, [int timeout = 500]) async {
    source!.setReadImageTimeout(timeout);
    return source!.getImage(index);
  }

  bool isBufferedDoneForFrames(int index) {
    if (_isVrdPlayer) {
      bool result = source!.getReader().frames.containsKey(index);
      if (result) {
        result = source!.getReader().frames[index]!.isNotEmpty;
      }
      return result;
    } else {
      return false;
    }
  }

  /// 关闭通道
  void close() {
    _initialized = false;
    try {
      source?.close();
    } catch (e) {}
  }

  @protected
  Future<AsyncVidImageDataBase> buildSource();
}