FrameTimingSummarizer constructor Null safety

Implementation

factory FrameTimingSummarizer(
  List<FrameTiming> data, {
  int? newGenGCCount,
  int? oldGenGCCount,
}) {
  assert(data != null);
  assert(data.isNotEmpty);
  final List<Duration> frameBuildTime = List<Duration>.unmodifiable(
    data.map<Duration>((FrameTiming datum) => datum.buildDuration),
  );
  final List<Duration> frameBuildTimeSorted =
      List<Duration>.from(frameBuildTime)..sort();
  final List<Duration> frameRasterizerTime = List<Duration>.unmodifiable(
    data.map<Duration>((FrameTiming datum) => datum.rasterDuration),
  );
  final List<Duration> frameRasterizerTimeSorted =
      List<Duration>.from(frameRasterizerTime)..sort();
  final List<Duration> vsyncOverhead = List<Duration>.unmodifiable(
    data.map<Duration>((FrameTiming datum) => datum.vsyncOverhead),
  );
  final List<int> layerCacheCounts = List<int>.unmodifiable(
    data.map<int>((FrameTiming datum) => datum.layerCacheCount),
  );
  final List<int> layerCacheCountsSorted = List<int>.from(layerCacheCounts)..sort();
  final List<int> layerCacheBytes = List<int>.unmodifiable(
    data.map<int>((FrameTiming datum) => datum.layerCacheBytes),
  );
  final List<int> layerCacheBytesSorted = List<int>.from(layerCacheBytes)..sort();
  final List<int> pictureCacheCounts = List<int>.unmodifiable(
    data.map<int>((FrameTiming datum) => datum.pictureCacheCount),
  );
  final List<int> pictureCacheCountsSorted = List<int>.from(pictureCacheCounts)..sort();
  final List<int> pictureCacheBytes = List<int>.unmodifiable(
    data.map<int>((FrameTiming datum) => datum.pictureCacheBytes),
  );
  final List<int> pictureCacheBytesSorted = List<int>.from(pictureCacheBytes)..sort();
  final List<Duration> vsyncOverheadSorted =
      List<Duration>.from(vsyncOverhead)..sort();
  Duration add(Duration a, Duration b) => a + b;
  int addInts(int a, int b) => a + b;
  return FrameTimingSummarizer._(
    frameBuildTime: frameBuildTime,
    frameRasterizerTime: frameRasterizerTime,
    vsyncOverhead: vsyncOverhead,
    // This average calculation is microsecond precision, which is fine
    // because typical values of these times are milliseconds.
    averageFrameBuildTime: frameBuildTime.reduce(add) ~/ data.length,
    p90FrameBuildTime: _findPercentile(frameBuildTimeSorted, 0.90),
    p99FrameBuildTime: _findPercentile(frameBuildTimeSorted, 0.99),
    worstFrameBuildTime: frameBuildTimeSorted.last,
    missedFrameBuildBudget: _countExceed(frameBuildTimeSorted, kBuildBudget),
    averageFrameRasterizerTime:
        frameRasterizerTime.reduce(add) ~/ data.length,
    p90FrameRasterizerTime: _findPercentile(frameRasterizerTimeSorted, 0.90),
    p99FrameRasterizerTime: _findPercentile(frameRasterizerTimeSorted, 0.99),
    worstFrameRasterizerTime: frameRasterizerTimeSorted.last,
    averageLayerCacheCount: layerCacheCounts.reduce(addInts) / data.length,
    p90LayerCacheCount: _findPercentile(layerCacheCountsSorted, 0.90),
    p99LayerCacheCount: _findPercentile(layerCacheCountsSorted, 0.99),
    worstLayerCacheCount: layerCacheCountsSorted.last,
    averageLayerCacheBytes: layerCacheBytes.reduce(addInts) / data.length,
    p90LayerCacheBytes: _findPercentile(layerCacheBytesSorted, 0.90),
    p99LayerCacheBytes: _findPercentile(layerCacheBytesSorted, 0.99),
    worstLayerCacheBytes: layerCacheBytesSorted.last,
    averagePictureCacheCount: pictureCacheCounts.reduce(addInts) / data.length,
    p90PictureCacheCount: _findPercentile(pictureCacheCountsSorted, 0.90),
    p99PictureCacheCount: _findPercentile(pictureCacheCountsSorted, 0.99),
    worstPictureCacheCount: pictureCacheCountsSorted.last,
    averagePictureCacheBytes: pictureCacheBytes.reduce(addInts) / data.length,
    p90PictureCacheBytes: _findPercentile(pictureCacheBytesSorted, 0.90),
    p99PictureCacheBytes: _findPercentile(pictureCacheBytesSorted, 0.99),
    worstPictureCacheBytes: pictureCacheBytesSorted.last,
    missedFrameRasterizerBudget:
        _countExceed(frameRasterizerTimeSorted, kBuildBudget),
    averageVsyncOverhead: vsyncOverhead.reduce(add) ~/ data.length,
    p90VsyncOverhead: _findPercentile(vsyncOverheadSorted, 0.90),
    p99VsyncOverhead: _findPercentile(vsyncOverheadSorted, 0.99),
    worstVsyncOverhead: vsyncOverheadSorted.last,
    newGenGCCount: newGenGCCount ?? -1,
    oldGenGCCount: oldGenGCCount ?? -1,
  );
}