QueryTask.cs

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using System.Threading;
using System.Threading.Tasks;
 
namespace System.Linq.Parallel;
 
internal abstract class QueryTask
{
    protected int _taskIndex;
 
    protected QueryTaskGroupState _groupState;
 
    private static readonly Action<object> s_runTaskSynchronouslyDelegate = RunTaskSynchronously;
 
    private static readonly Action<object> s_baseWorkDelegate = delegate(object o)
    {
        ((QueryTask)o).BaseWork(null);
    };
 
    protected QueryTask(int taskIndex, QueryTaskGroupState groupState)
    {
        _taskIndex = taskIndex;
        _groupState = groupState;
    }
 
    private static void RunTaskSynchronously(object o)
    {
        ((QueryTask)o).BaseWork(null);
    }
 
    internal Task RunSynchronously(TaskScheduler taskScheduler)
    {
        Task task = new Task(s_runTaskSynchronouslyDelegate, this, TaskCreationOptions.AttachedToParent);
        task.RunSynchronously(taskScheduler);
        return task;
    }
 
    internal Task RunAsynchronously(TaskScheduler taskScheduler)
    {
        return Task.Factory.StartNew(s_baseWorkDelegate, this, CancellationToken.None, TaskCreationOptions.PreferFairness | TaskCreationOptions.AttachedToParent, taskScheduler);
    }
 
    private void BaseWork(object unused)
    {
        PlinqEtwProvider.Log.ParallelQueryFork(_groupState.QueryId);
        try
        {
            Work();
        }
        finally
        {
            PlinqEtwProvider.Log.ParallelQueryJoin(_groupState.QueryId);
        }
    }
 
    protected abstract void Work();
}