开源库evio源码学习

开源库evio源码学习

tcp自动识别包的大小

通过创建足够大的字节切片，读取之后，通过下面的n可以知道有数据的长度

n, err := c.conn.Read(packet[:])
if err != nil {
c.conn.SetReadDeadline(time.Time{})
l.ch <- &stderr{c, err}
return
}
// todo: 这个牛逼
fmt.Println("packet解析： ", string(packet[:n]))
l.ch <- &stdin{c, append([]byte{}, packet[:n]...)}

我又把服务器的返回的数据也读取了一下

package main

import (
	"context"
	"fmt"
	"log"
	"net"
	"time"
)

func main() {
	var d net.Dialer
	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
	defer cancel()

	conn, err := d.DialContext(ctx, "tcp", "localhost:5000")
	if err != nil {
		log.Fatalf("Failed to dial: %v", err)
	}
	defer conn.Close()

	data := []byte("茅厕")
	if _, err := conn.Write(data); err != nil {
		log.Fatal(err)
	}

	data2 := make([]byte, 300)
	read, err := conn.Read(data2)
	fmt.Println("read", read)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(string(data2))
	fmt.Println(read)

	fmt.Println(int(0xFFFF))
}

evio的重要数据结构

// Events represents the server events for the Serve call.
// Each event has an Action return value that is used manage the state
// of the connection and server.
type Events struct {
	// NumLoops sets the number of loops to use for the server. Setting this
	// to a value greater than 1 will effectively make the server
	// multithreaded for multi-core machines. Which means you must take care
	// with synchonizing memory between all event callbacks. Setting to 0 or 1
	// will run the server single-threaded. Setting to -1 will automatically
	// assign this value equal to runtime.NumProcs().
	NumLoops int
	// LoadBalance sets the load balancing method. Load balancing is always a
	// best effort to attempt to distribute the incoming connections between
	// multiple loops. This option is only works when NumLoops is set.
	LoadBalance LoadBalance
	// Serving fires when the server can accept connections. The server
	// parameter has information and various utilities.
	Serving func(server Server) (action Action)
	// Opened fires when a new connection has opened.
	// The info parameter has information about the connection such as
	// it's local and remote address.
	// Use the out return value to write data to the connection.
	// The opts return value is used to set connection options.
	Opened func(c Conn) (out []byte, opts Options, action Action)
	// Closed fires when a connection has closed.
	// The err parameter is the last known connection error.
	Closed func(c Conn, err error) (action Action)
	// Detached fires when a connection has been previously detached.
	// Once detached it's up to the receiver of this event to manage the
	// state of the connection. The Closed event will not be called for
	// this connection.
	// The conn parameter is a ReadWriteCloser that represents the
	// underlying socket connection. It can be freely used in goroutines
	// and should be closed when it's no longer needed.
	Detached func(c Conn, rwc io.ReadWriteCloser) (action Action)
	// PreWrite fires just before any data is written to any client socket.
	PreWrite func()
	// Data fires when a connection sends the server data.
	// The in parameter is the incoming data.
	// Use the out return value to write data to the connection.
	Data func(c Conn, in []byte) (out []byte, action Action)
	// Tick fires immediately after the server starts and will fire again
	// following the duration specified by the delay return value.
	Tick func() (delay time.Duration, action Action)
}

type stdserver struct {
	events   Events         // user events
	loops    []*stdloop     // all the loops
	lns      []*listener    // all the listeners
	loopwg   sync.WaitGroup // loop close waitgroup
	lnwg     sync.WaitGroup // listener close waitgroup
	cond     *sync.Cond     // shutdown signaler
	serr     error          // signal error
	accepted uintptr        // accept counter
}

type stdloop struct {
	idx   int               // loop index
	ch    chan interface{}  // command channel
	conns map[*stdconn]bool // track all the conns bound to this loop
}

核心就是Data 的注册，接手一条消息就去用chan 通知处理一条，并没有真正的体现epoll

Epoll文章

https://blog.csdn.net/armlinuxww/article/details/92803381