C#实现Unity协程

原理

利用c#的yied特性，利用迭代器，在每一帧tickIEnumerator 用来保存迭代状态，用于恢复迭代器中的代码执行点unity中协程调用位置

普通迭代器

//继承IEnumerable接口，其实也可以不继承这个接口，只要类里面含有返回IEnumberator引用的GetEnumerator()方法即可 class ForeachTest : IEnumerable { private string[] elements; //装载字符串的数组 private int ctr = 0; //数组的下标计数器 /// <summary> /// 初始化的字符串 /// </summary> /// <param name="initialStrings"></param> ForeachTest(params string[] initialStrings) { //为字符串分配内存空间 elements = new String[8]; //复制传递给构造方法的字符串 foreach (string s in initialStrings) { elements[ctr++] = s; } } /// <summary> /// 构造函数 /// </summary> /// <param name="source">初始化的字符串</param> /// <param name="delimiters">分隔符，可以是一个或多个字符分隔</param> ForeachTest(string initialStrings, char[] delimiters) { elements = initialStrings.Split(delimiters); } //实现接口中得方法 public IEnumerator GetEnumerator() { return new ForeachTestEnumerator(this); } private class ForeachTestEnumerator : IEnumerator { private int position = -1; private ForeachTest t; public ForeachTestEnumerator(ForeachTest t) { this.t = t; } #region 实现接口 public object Current { get { return t.elements[position]; } } public bool MoveNext() { if (position < t.elements.Length - 1) { position++; return true; } else { return false; } } public void Reset() { position = -1; } #endregion } }

c#利用迭代器实现协程

class MainEntry { static int frame = 0; static public IEnumerator WaitCoroutine() { Console.WriteLine("begin"); yield return null; Console.WriteLine("Coroutine{0}", frame); yield return new WaitFream(10); Console.WriteLine("Coroutine{0}", frame); yield return null; Console.WriteLine("end"); } //协程迭代5帧 static public IEnumerator CoroutineDo5Frame() { while (true) { if(frame >= 5) { break; } Console.WriteLine("CoroutineTick"); yield return null; } } //等待给定帧数 class WaitFream { int wait_count = 0; public WaitFream(int count) { wait_count = count; } public bool Tick() { return --wait_count > 0; } } static LinkedList<IEnumerator> CoroutineList = new LinkedList<IEnumerator>(); static void StartCoroutine(IEnumerator enumerator) { CoroutineList.AddLast(enumerator); } static void CoroutineTick() { var node = CoroutineList.First; while(node != null) { IEnumerator cur_etor = node.Value; bool ret = true; if (cur_etor.Current is WaitFream) { WaitFream wf = (WaitFream)cur_etor.Current; if (!wf.Tick()) { ret = cur_etor.MoveNext(); } } else { ret = cur_etor.MoveNext(); } //删除节点 if(ret == false) { CoroutineList.Remove(node); } node = node.Next; } } static void Main(string[] args) { // ForeachTest f = new ForeachTest("This is a sample sentence.", new char[] { ' ', '-' }); StartCoroutine(WaitCoroutine()); StartCoroutine(CoroutineDo5Feam()); while (true) { frema++; Console.WriteLine("trunk loop frame:{0}", frame); CoroutineTick(); Console.ReadLine(); } } } }

yiled的原理

仅仅是一个语法糖，用switch case 将不同yiled之间的代码块隔开，movenext时执行代码块并且改变到下一个执行状态，下次执行时将执行下一个代码块，将yield后面的值赋值给current值

反编译语法糖展开代码

class Program { static void Main(string[] args) { //这儿调用了方法。 var test = Power(2, 8, ""); Console.WriteLine("Begin to iterate the collection."); //Display powers of 2 up to the exponent of 8: foreach (int i in Power(2, 8, "")) { Console.Write("{0} ", i); } Console.ReadKey(); } public static IEnumerable<int> Power(int number, int exponent, string s) { int result = 1; if (string.IsNullOrEmpty(s)) { Console.WriteLine("Begin to invoke GetItems() method"); } for (int i = 0; i < exponent; i++) { result = result * number; yield return result; } yield return 3; yield return 4; yield return 5; } } 反编译语法糖的代码 namespace ConsoleApplication2 { using System; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Runtime.CompilerServices; internal class Program { private static void Main(string[] args) { IEnumerable<int> enumerable = Power(2, 8, ""); Console.WriteLine("Begin to iterate the collection."); foreach (int num in Power(2, 8, "")) { Console.Write("{0} ", num); } Console.ReadKey(); } public static IEnumerable<int> Power(int number, int exponent, string s) { <Power>d__0 d__ = new <Power>d__0(-2); d__.<>3__number = number; d__.<>3__exponent = exponent; d__.<>3__s = s; return d__; } [CompilerGenerated] private sealed class <Power>d__0 : IEnumerable<int>, IEnumerable, IEnumerator<int>, IEnumerator, IDisposable { private int <>1__state; private int <>2__current; public int <>3__exponent; public int <>3__number; public string <>3__s; private int <>l__initialThreadId; public int <i>5__2; public int <result>5__1; public int exponent; public int number; public string s; [DebuggerHidden] public <Power>d__0(int <>1__state) { this.<>1__state = <>1__state; this.<>l__initialThreadId = Environment.CurrentManagedThreadId; } private bool MoveNext() { switch (this.<>1__state) { case 0: this.<>1__state = -1; this.<result>5__1 = 1; if (string.IsNullOrEmpty(this.s)) { Console.WriteLine("Begin to invoke GetItems() method"); } this.<i>5__2 = 0; while (this.<i>5__2 < this.exponent) { this.<result>5__1 *= this.number; this.<>2__current = this.<result>5__1; this.<>1__state = 1; return true; Label_009D: this.<>1__state = -1; this.<i>5__2++; } this.<>2__current = 3; this.<>1__state = 2; return true; case 1: goto Label_009D; case 2: this.<>1__state = -1; this.<>2__current = 4; this.<>1__state = 3; return true; case 3: this.<>1__state = -1; this.<>2__current = 5; this.<>1__state = 4; return true; case 4: this.<>1__state = -1; break; } return false; } [DebuggerHidden] IEnumerator<int> IEnumerable<int>.GetEnumerator() { Program.<Power>d__0 d__; if ((Environment.CurrentManagedThreadId == this.<>l__initialThreadId) && (this.<>1__state == -2)) { this.<>1__state = 0; d__ = this; } else { d__ = new Program.<Power>d__0(0); } d__.number = this.<>3__number; d__.exponent = this.<>3__exponent; d__.s = this.<>3__s; return d__; } [DebuggerHidden] IEnumerator IEnumerable.GetEnumerator() { return this.System.Collections.Generic.IEnumerable<System.Int32>.GetEnumerator(); } [DebuggerHidden] void IEnumerator.Reset() { throw new NotSupportedException(); } void IDisposable.Dispose() { } int IEnumerator<int>.Current { [DebuggerHidden] get { return this.<>2__current; } } object IEnumerator.Current { [DebuggerHidden] get { return this.<>2__current; } } } } }

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