path: root/server.go

package main

import (
    "container/list"
    "github.com/ethereum/ethdb-go"
    "github.com/ethereum/ethutil-go"
    "github.com/ethereum/ethwire-go"
    "log"
    "net"
    "time"
    "sync/atomic"
)

func eachPeer(peers *list.List, callback func(*Peer, *list.Element)) {
    // Loop thru the peers and close them (if we had them)
    for e := peers.Front(); e != nil; e = e.Next() {
        if peer, ok := e.Value.(*Peer); ok {
            callback(peer, e)
        }
    }
}


type Server struct {
    // Channel for shutting down the server
    shutdownChan chan bool
    // DB interface
    //db *ethdb.LDBDatabase
    db *ethdb.MemDatabase
    // Block manager for processing new blocks and managing the block chain
    blockManager *BlockManager
    // Peers (NYI)
    peers *list.List
    // Nonce
    Nonce uint64
}

func NewServer() (*Server, error) {
    //db, err := ethdb.NewLDBDatabase()
    db, err := ethdb.NewMemDatabase()
    if err != nil {
        return nil, err
    }

    ethutil.SetConfig(db)

    nonce, _ := ethutil.RandomUint64()
    server := &Server{
        shutdownChan: make(chan bool),
        blockManager: NewBlockManager(),
        db:           db,
        peers:        list.New(),
        Nonce:        nonce,
    }

    return server, nil
}

func (s *Server) AddPeer(conn net.Conn) {
    peer := NewPeer(conn, s, true)

    if peer != nil {
        s.peers.PushBack(peer)
        peer.Start()

        log.Println("Peer connected ::", conn.RemoteAddr())
    }
}

func (s *Server) ConnectToPeer(addr string) error {
    peer := NewOutboundPeer(addr, s)

    s.peers.PushBack(peer)

    return nil
}

func (s *Server) Broadcast(msgType string, data []byte) {
    eachPeer(s.peers, func(p *Peer, e *list.Element) {
        p.QueueMessage(ethwire.NewMessage(msgType, 0, data))
    })
}

const (
    processReapingTimeout            = 10 // TODO increase
)

func (s *Server) ReapDeadPeers() {
    for {
        eachPeer(s.peers, func(p *Peer, e *list.Element) {
            if atomic.LoadInt32(&p.disconnect) == 1 {
                log.Println("Dead peer found .. reaping")

                s.peers.Remove(e)
            }
        })

        time.Sleep(processReapingTimeout * time.Second)
    }
}

// Start the server
func (s *Server) Start() {
    // For now this function just blocks the main thread
    ln, err := net.Listen("tcp", ":12345")
    if err != nil {
        // This is mainly for testing to create a "network"
        if Debug {
            log.Println("Connection listening disabled. Acting as client")

            err = s.ConnectToPeer("localhost:12345")
            if err != nil {
                log.Println("Error starting server", err)

                s.Stop()
            }

            return
        } else {
            log.Fatal(err)
        }
    }

    // Start the reaping processes
    go s.ReapDeadPeers()

    go func() {
        for {
            conn, err := ln.Accept()
            if err != nil {
                log.Println(err)

                continue
            }

            go s.AddPeer(conn)
        }
    }()

    // TMP
    go func() {
        //time.Sleep(500 * time.Millisecond)

        for {
            s.Broadcast("block", s.blockManager.bc.GenesisBlock().MarshalRlp())

            time.Sleep(1000 * time.Millisecond)
        }
    }()
}

func (s *Server) Stop() {
    // Close the database
    defer s.db.Close()

    eachPeer(s.peers, func(p *Peer, e *list.Element) {
            p.Stop()
    })

    s.shutdownChan <- true
}

// This function will wait for a shutdown and resumes main thread execution
func (s *Server) WaitForShutdown() {
    <-s.shutdownChan
}