New coroutine interface for Unity.

TaskManager.cs

/// TaskManager.cs
/// Copyright (c) 2011, Ken Rockot  <k-e-n-@-REMOVE-CAPS-AND-HYPHENS-oz.gs>.  All rights reserved.
/// Added a inline delegate to it. @onevcat
/// Everyone is granted non-exclusive license to do anything at all with this code.
///
/// This is a new coroutine interface for Unity.
///
/// The motivation for this is twofold:
///
/// 1. The existing coroutine API provides no means of stopping specific
///    coroutines; StopCoroutine only takes a string argument, and it stops
///    all coroutines started with that same string; there is no way to stop
///    coroutines which were started directly from an enumerator.  This is
///    not robust enough and is also probably pretty inefficient.
///
/// 2. StartCoroutine and friends are MonoBehaviour methods.  This means
///    that in order to start a coroutine, a user typically must have some
///    component reference handy.  There are legitimate cases where such a
///    constraint is inconvenient.  This implementation hides that
///    constraint from the user.
///
/// Example usage:
///
/// ----------------------------------------------------------------------------
/// IEnumerator MyAwesomeTask()
/// {
///     while(true) {
///         Debug.Log("Logcat iz in ur consolez, spammin u wif messagez.");
///         yield return null;
////    }
/// }
///
/// IEnumerator TaskKiller(float delay, Task t)
/// {
///     yield return new WaitForSeconds(delay);
///     t.Stop();
/// }
///
/// void SomeCodeThatCouldBeAnywhereInTheUniverse()
/// {
///     Task spam = new Task(MyAwesomeTask());
///     new Task(TaskKiller(5, spam));
/// }
/// ----------------------------------------------------------------------------
///
/// When SomeCodeThatCouldBeAnywhereInTheUniverse is called, the debug console
/// will be spammed with annoying messages for 5 seconds.
///
/// Simple, really.  There is no need to initialize or even refer to TaskManager.
/// When the first Task is created in an application, a "TaskManager" GameObject
/// will automatically be added to the scene root with the TaskManager component
/// attached.  This component will be responsible for dispatching all coroutines
/// behind the scenes.
///
/// Task also provides an event that is triggered when the coroutine exits.

using UnityEngine;
using System.Collections;

/// A Task object represents a coroutine.  Tasks can be started, paused, and stopped.
/// It is an error to attempt to start a task that has been stopped or which has
/// naturally terminated.
public class Task
{
  /// Returns true if and only if the coroutine is running.  Paused tasks
	/// are considered to be running.
	public bool Running
	{
		get
		{
			return task.Running;
		}
	}

	/// Returns true if and only if the coroutine is currently paused.
	public bool Paused
	{
		get
		{
			return task.Paused;
		}
	}

	/// Delegate for termination subscribers.  manual is true if and only if
	/// the coroutine was stopped with an explicit call to Stop().
	public delegate void FinishedHandler(bool manual);

	/// Termination event.  Triggered when the coroutine completes execution.
	public event FinishedHandler Finished;

	/// Creates a new Task object for the given coroutine.
	///
	/// If autoStart is true (default) the task is automatically started
	/// upon construction.
	public Task(IEnumerator c, bool autoStart = true)
	{
		task = TaskManager.CreateTask(c);
		task.Finished += TaskFinished;
		if (autoStart)
			Start();
	}

	public Task(IEnumerator c, FinishedHandler handler, bool autoStart = true) : this(c,autoStart){
		Finished += handler;
	}

	/// Begins execution of the coroutine
	public void Start()
	{
		task.Start();
	}

	/// Discontinues execution of the coroutine at its next yield.
	public void Stop()
	{
		task.Stop();
	}

	public void Pause()
	{
		task.Pause();
	}

	public void Unpause()
	{
		task.Unpause();
	}

	void TaskFinished(bool manual)
	{
		FinishedHandler handler = Finished;
		if (handler != null)
			handler(manual);
	}

	TaskManager.TaskState task;
}

class TaskManager : MonoBehaviour
{
	public class TaskState
	{
		public bool Running
		{
			get
			{
				return running;
			}
		}

		public bool Paused
		{
			get
			{
				return paused;
			}
		}

		public delegate void FinishedHandler(bool manual);
		public event FinishedHandler Finished;

		IEnumerator coroutine;
		bool running;
		bool paused;
		bool stopped;

		public TaskState(IEnumerator c)
		{
			coroutine = c;
		}

		public void Pause()
		{
			paused = true;
		}

		public void Unpause()
		{
			paused = false;
		}

		public void Start()
		{
			running = true;
			singleton.StartCoroutine(CallWrapper());
		}

		public void Stop()
		{
			stopped = true;
			running = false;
		}

		IEnumerator CallWrapper()
		{
			yield return null;
			IEnumerator e = coroutine;
			while (running)
			{
				if (paused)
					yield return null;
				else
				{
					if (e != null && e.MoveNext())
					{
						yield return e.Current;
					}
					else
					{
						running = false;
					}
				}
			}

			FinishedHandler handler = Finished;
			if (handler != null)
				handler(stopped);
		}
	}

	static TaskManager singleton;

	public static TaskState CreateTask(IEnumerator coroutine)
	{
		if (singleton == null)
		{
			GameObject go = new GameObject("TaskManager");
			singleton = go.AddComponent<TaskManager>();
		}
		return new TaskState(coroutine);
	}
}