core: Prototype tor control connection and API

core/network.go

@@ -1,15 +1,169 @@
 package core
 
-type NetworkStatus int
-
-const (
-	NetworkUnavailable NetworkStatus = iota
-	NetworkError
-	NetworkOffline
-	NetworkOnline
+import (
+	"errors"
+	"github.com/special/ricochet-go/core/utils"
+	"github.com/yawning/bulb"
+	bulbutils "github.com/yawning/bulb/utils"
+	"log"
+	"sync"
+	"time"
 )
 
 type Network struct {
-	torConfig *TorConfiguration
-	status    NetworkStatus
+	conn *bulb.Conn
+
+	controlAddress  string
+	controlPassword string
+
+	handleLock  sync.Mutex
+	stopChannel chan struct{}
+
+	events *utils.Publisher
+}
+
+func CreateNetwork() *Network {
+	return &Network{
+		events: utils.CreatePublisher(),
+	}
+}
+
+// Start connection to the tor control port at 'address', with the optional
+// control password 'password'. This function blocks until the first connection
+// attempt is finished. The first return value says whether the connection has
+// been started; if true, the connection is up even if the first attempt failed.
+// The second return value is the connection attempt error, or nil on success.
+func (n *Network) Start(address, password string) (bool, error) {
+	n.handleLock.Lock()
+	defer n.handleLock.Unlock()
+
+	if n.stopChannel != nil {
+		// This is an error, because address/password might not be the same
+		return false, errors.New("Network is already started")
+	}
+
+	n.stopChannel = make(chan struct{})
+	n.controlAddress = address
+	n.controlPassword = password
+
+	connectChannel := make(chan error)
+
+	go n.run(connectChannel)
+	err := <-connectChannel
+	return true, err
+}
+
+// Stop the network connection. The externally-controlled tor instance
+// is not affected, but the control port connection will be closed and
+// the client will be offline until Start is called again. This call will
+// block until the connection is stopped.
+func (n *Network) Stop() {
+	n.handleLock.Lock()
+	defer n.handleLock.Unlock()
+
+	if n.stopChannel == nil {
+		return
+	}
+
+	// XXX but if we do block that long, we can hold the mutex a _long_ time.
+	// XXX so the mutex won't be suitable for a "is network started" check
+	n.stopChannel <- struct{}{}
+	n.stopChannel = nil
+	n.conn = nil
+	n.controlAddress = ""
+	n.controlPassword = ""
+}
+
+func (n *Network) EventMonitor() utils.Subscribable {
+	return n.events
+}
+
+func (n *Network) run(connectChannel chan<- error) {
+	var conn *bulb.Conn
+	var err error
+
+	for {
+		conn, err = createConnection(n.controlAddress, n.controlPassword)
+
+		// Report result of the first connection attempt
+		if connectChannel != nil {
+			connectChannel <- err
+			close(connectChannel)
+			connectChannel = nil
+		}
+
+		retryChannel := make(chan struct{}, 1)
+
+		if err == nil {
+			// Success! Set connection, handle events, and retry connection
+			// if it fails
+			n.conn = conn
+			n.events.Publish(true)
+			go func() {
+				for {
+					event, err := conn.NextEvent()
+					if err != nil {
+						log.Printf("Control connection failed: %v", err)
+						n.events.Publish(false)
+						retryChannel <- struct{}{}
+						break
+					}
+					log.Printf("Control event: %v", event)
+				}
+			}()
+		} else {
+			// Failed; retry in one second
+			go func() {
+				time.Sleep(1 * time.Second)
+				retryChannel <- struct{}{}
+			}()
+		}
+
+		select {
+		case <-n.stopChannel:
+			break
+		case <-retryChannel:
+			if conn != nil {
+				conn.Close()
+			}
+		}
+	}
+
+	// Stopped
+	if conn != nil {
+		conn.Close()
+	}
+}
+
+func createConnection(address, password string) (*bulb.Conn, error) {
+	net, addr, err := bulbutils.ParseControlPortString(address)
+	if err != nil {
+		log.Printf("Parsing control network address '%s' failed: %v", address, err)
+		return nil, err
+	}
+
+	conn, err := bulb.Dial(net, addr)
+	if err != nil {
+		log.Printf("Control connection failed: %v", err)
+		return nil, err
+	}
+
+	err = conn.Authenticate(password)
+	if err != nil {
+		log.Printf("Control authentication failed: %v", err)
+		conn.Close()
+		return nil, err
+	}
+
+	conn.StartAsyncReader()
+
+	// XXX
+	if _, err := conn.Request("SETEVENTS STATUS_CLIENT"); err != nil {
+		log.Printf("Control events failed: %v", err)
+		conn.Close()
+		return nil, err
+	}
+
+	log.Print("Control connected!")
+	return conn, nil
 }