Merge pull request #659 from nofficalfs/Dev-GoLikeChannel

Add `lib.channel` to give a method of message receiving.

game/game.js

@@ -363,6 +363,108 @@ new Promise(resolve=>{
 				}
 			}],
 		},
+		/**
+		 * **无名杀频道推送机制**
+		 * 
+		 * 鉴于`Javascript`的特性及自身对所需功能的思考，这是一个参考`Golang`的`channel`设计的、完全和`go channel`不一样的异步消息传递对象
+		 * 
+		 * 当且仅当接收方和发送方均存在时进行消息传递，完全保证信息传递的单一性（发送方/接收方一旦确定则无法更改）和准确性（发送方必然将消息发送给接收方）
+		 * 
+		 * 若存在发送方/接收方时调用`send`/`receive`，将报错
+		 * 
+		 * 若需要异步/不报错发送信息，请等待`lib.actor`
+		 * 
+		 * @template T
+		 * @example
+		 * // 创建一个频道
+		 * const channel = new lib.channel();
+		 * 
+		 * // 从某个角落接收channel发出的消息，若无消息则等待
+		 * const message = await channel.receive();
+		 * 
+		 * // 从某个角落向channel发消息，若无消息接收则等待
+		 * await channel.send(item);
+		 */
+		channel: class {
+			/**
+			 * @template TValue
+			 * @callback PromiseResolve
+			 * @param {TValue} value
+			 * @returns {void}
+			 */
+			constructor() {
+				/**
+				 * @type {"active" | "receiving" | "sending"}
+				 */
+				this.status = "active";
+
+				/**
+				 * @type {PromiseResolve<T> | [T, PromiseResolve<void>] | null}
+				 */
+				this._buffer = null;
+			}
+
+			/**
+			 * 向该频道发送消息，在消息未被接受前将等待
+			 * 
+			 * @param {T} value - 要发送的消息
+			 * @returns {Promise<void>}
+			 */
+			send(value) {
+				return new Promise((resolve, reject) => {
+					switch (this.status) {
+						case "sending":
+							// TODO: handle the error.
+							reject(new Error());
+							break;
+						case "receiving":
+							/**
+							 * @type {PromiseResolve<T>}
+							 */
+							const buffer = this._buffer;
+							this._buffer = null;
+							buffer(value);
+							this.status = "active";
+							resolve();
+							break ;
+						case "active":
+							this.status = "sending";
+							this._buffer = [value, resolve];
+							break;
+					}
+				});
+			}
+
+			/**
+			 * 接收频道所发送的消息，若无消息发送则等待
+			 * 
+			 * @returns {Promise<T>} 接收到的消息
+			 */
+			receive() {
+				return new Promise((resolve, reject) => {
+					switch (this.status) {
+						case "receiving":
+							// TODO: handle the error.
+							reject(new Error());
+							break;
+						case "sending":
+							/**
+							 * @type {[T, PromiseResolve<void>]}
+							 */
+							const buffer = this._buffer;
+							this._buffer = null;
+							resolve(buffer[0]);
+							this.status = "active";
+							buffer[1]();
+							break ;
+						case "active":
+							this.status = "receiving";
+							this._buffer = resolve;
+							break;
+					}
+				});
+			}
+		},
 		/**
 		 * **无名杀消息推送库**
 		 *