在C++中实现协程

发表于 更新于 阅读次数： 本文字数： 7k 阅读时长 ≈ 6 分钟

我在整理tars和taf的协程逻辑的时候，也实现了一个纯净版的协程框架以便于理解

网络框架

类图

sheep_cpp

看下把tcpconnection改成回调中智能指针是否合理

classDiagram
direction TB
class EventLoop {
	+void wait()
    +void stop()
    +void addPoller(uint64_t type, shared_ptr~Poller~ poller)
    +weak_ptr<Poller> getPoller(uint64_t pollerType)\n在Connector和Acceptor中用来给TcpConnection创建Event的时候指定Poller
    -map&lt;uint64_t, shared_ptr&lt;Poller&gt;&gt; pollers_;
}
class Poller {
	<<interface>>
	+vector&lt;weak_ptr&lt;Event&gt;&gt; poll(string&)
	+void addOrUpdateEvent(shared_ptr<Event> event)
	+void removeEvent(Event *event)
}
class Epoller {
	+vector&lt;weak_ptr&lt;Event&gt;&gt; poll(string&)
	+void addOrUpdateEvent(shared_ptr~Event~ event)
	+void removeEvent(Event *event)
}
class Event {
	+Event(weak_ptr~Poller~ poller, int64_t fd)
	+void setReadEvent(function&lt;void#40;#41;&gt;)
	+void setWriteEvent(function&lt;void#40;#41;&gt;)
	-weak_ptr~Poller~ poller_;
}
Epoller ..|> Poller
EventLoop ..> Poller
Epoller ..> Event
Event ..> Poller

class Socket {
	+void bind(const string &addr, int port) Acceptor使用
	+void listen() Acceptor使用
	+void accept() Acceptor使用
	+void connect(const string &addr, int port) Connector使用
	+int read(char* buf, int len) TcpConnection使用
    +int write(char* buf, int len) TcpConnection使用
    +void setNoblock()
}
class Buffer {
	+void push(const char *buf, uint64_t len)
	+uint64_t popHead(char *buf, uint64_t len)
	-void write(const char *buf, uint64_t len) TcpConnection使用
	-uint64_t Read(char *buf, uint64_t len) TcpConnection使用
}

class TcpConnection {
	+TcpConnection(unique_ptr~Socket~ &&socket, shared_ptr~Event~ &event)
	+void asyncRead(uint64_t expectSize, function&lt;void#40;const string &errMsg#41;&gt; func)
    +void asyncReadAny(function&lt;void#40;const string &errMsg#41;&gt;)
    +void asyncWrite(function&lt;void#40;const string &errMsg#41;&gt;)
    +void finish(const string &errMsg)
    -void initAccepted(string &errMsg)
    -void initConnected(string &errMsg)
    -void setFinishHandler(function&lt;void#40;const string &errMsg,\nshared_ptr&lt;TcpConnection&gt;&#41;&gt;)
    -Buffer readBuffer_;
    -Buffer writeBuffer_;
	-unique_ptr~Socket~ socket_;
	-shared_ptr~Event~ event_;
}

class Acceptor {
	+Acceptor(EventLoop &loop, const string &addr, int port)
	+void listen(string &errMsg)
	+void setNewConnectionHandler(function&lt;void#40;int fd#41;&gt;)
	-unique_ptr~Socket~ socket_;
	-shared_ptr~Event~ event_;
}

class Connector {
	Connector(EventLoop &loop, const string &addr, int port)
	+void connect(string &errMsg)
	+void setNewConnectionHandler(function&lt;void#40;unique_ptr&lt;Socket&gt;&,\nshared_ptr&lt;Event&gt;&#41;&gt;)
	+void setConnectFailedHandler(function&lt;void#40;const string &errMsg#41;&gt;)
	-unique_ptr~Socket~ socket_;
	-shared_ptr~Event~ event_;
}

Socket --* TcpConnection
Buffer --o TcpConnection
Event --o TcpConnection

Socket --* Acceptor
Event --o Acceptor

Socket --* Connector
Event --o Connector

class Server {
	+Server(EventLoop &loop, const string &addr, int port)
	+void serve(string &errMsg)
	+void setConnectedHandler(function&lt;void#40;const string &errMsg,TcpConnection&#41;&gt;)\n连接成功以后，在connected回调的参数来获取连接读取数据
	+void setDisconnectedHandler(function&lt;void#40;const string &errMsg#41;&gt;)
	-Acceptor acceptor_;
	set~shared_ptr~TcpConnection~~ connections_;
}
TcpConnection --o Server
Acceptor --* Server
Client --> EventLoop

class Client {
	+Client(EventLoop &loop, const string &addr, int port)
	+void asyncConnect(string &errMsg)
	+void setConnectedHandler(function&lt;void#40;const string &errMsg#41;&gt;)
	+void setDisconnectedHandler(function&lt;void#40;const string &errMsg#41;&gt;)
	+TcpConnection& getTcpConnection()\n连接成功以后，在connected回调中调用来获取连接读取数据
	-Connector connector_;
	-shared_ptr~TcpConnection~ connection_;
}
Connector --* Client
TcpConnection --o Client
Server --> EventLoop

服务端流程图

sequenceDiagram
participant EventLoop
Server ->>+ Server : serve()
Server ->>+ Acceptor : setNewConnectionHandler()<br>listen()
Acceptor ->>- Server : return
Server ->>- Server : return
EventLoop ->>+ EventLoop : wait()
loop while(true)
EventLoop ->>+ EventLoop : runOnce()
EventLoop ->>+ Epoller : auto events = poll()
Epoller ->> Epoller : ::epoll_wait(epollfd_, &(*pollEvents_.begin()), maxSize_)
Epoller ->>- EventLoop : return
loop for event in events 
EventLoop ->>+ Event : do()
Event ->>+ EventLoop : return
end
EventLoop ->>- EventLoop : return
end
EventLoop ->>- EventLoop : return

客户端流程图

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```



## 协程框架

协程实现在这里[sheep_cpp/src/coroutine/](https://github.com/tedcy/sheep_cpp/tree/e2a97cdda05d4c252cb517051c10a75a7af4fb66/src/coroutine)

### 类图

```mermaid
classDiagram
direction TB
namespace 协程框架 {
class CoroutineInfo协程 {
	+void registerFunc()
	+void switchTo(CoroutineInfo *to) 切换到目标协程
	+void switchBack() 切换回主协程
}
class CoroutineScheduler协程调度器 {
    +void start() 用于启动这个协程调度器在独立线程里
    +void addCoroutine(F && func) 用于其他线程给这个线程添加协程任务
    +void yield() 用于挂起协程，让给其他协程执行，空闲时再转回自己
    +void suspend() 用于挂起协程，必须通过resume唤醒
    +void resume(CoroutineInfo*) 用于唤醒suspend挂起的协程
    +void sleep() 用于定时休眠后唤醒，可以用suspend和resume封装
}
class CoSharedState["CoSharedState&lt;T&gt;"] {
	+void setValue(T && t)
	+void setException(std::exception_ptr p)
	+void wait(int ms) 在线程或协程内，使用各自版本的cv + lock
}
class CoPromise["CoPromise&lt;T&gt;"] {
	+CoFuture&lt;T&gt; getFuture()
	+void setValue(T && t)
	+void setException(std::exception_ptr p)
	-shared_ptr~SharedState~T~~ state : \n和CoFuture共享同一个SharedState
}
class CoFuture["CoFuture&lt;T&gt;"] {
	+T wait(int ms = -1)
	-shared_ptr~SharedState~T~~ state : \n和CoPromise共享同一个SharedState
}
class CoASyncer {
	+CoFuture&lt;T&gt async(F && func) 异步执行func，并获取一个CoFuture
}
class CoMutex {
	+void lock()
	+void unlock()
}
class CoConditionValue {
	+void wait(int ms = -1)
	+void notify_one()
	+void notify_all()
}
}
CoroutineInfo协程 "N" --* CoroutineScheduler协程调度器
CoSharedState ..> CoMutex
CoSharedState ..> CoConditionValue
CoPromise ..> CoSharedState
CoFuture ..> CoSharedState
CoASyncer ..> CoFuture
CoMutex ..> CoroutineScheduler协程调度器
CoConditionValue ..> CoroutineScheduler协程调度器
CoASyncer ..> CoroutineScheduler协程调度器
namespace 网络框架 {
class EventLoop事件循环 {
	-void run() 在一轮poller后调用yield
}
class Server {
	+void setConnectedHandler() \n连接建立以后创建一个新协程
}
class Client {
	+void asyncConnect(F && func)
	+void connect(): \n创建一个CoPromise，\n调用AsyncConnect的func里面对其setValue()，\n外面的CoFuture去wait()
}
class TcpConnection {
	+void asyncRead(F && func)
	+void read() 同AsyncConnect
}
}
note for EventLoop事件循环 "1 服务端线程整个由调度器托管<br>EventLoop是调度器的一个协程<br>2 异步回调可以全部套一层<br>来实现同步回调"
EventLoop事件循环 ..> CoroutineScheduler协程调度器
Client ..> CoPromise
Client ..> TcpConnection
Server ..> EventLoop事件循环
Server ..> TcpConnection
TcpConnection ..> CoPromise