Add network.channels, remove DB.GetChannel

Store the list of configured channels in the network data structure.
This removes the need for a database lookup and will be useful for
detached channels.

db.go

@@ -48,8 +48,6 @@ type Channel struct {
 	Key  string
 }
 
-var ErrNoSuchChannel = fmt.Errorf("soju: no such channel")
-
 const schema = `
 CREATE TABLE User (
 	username VARCHAR(255) PRIMARY KEY,
@@ -371,23 +369,6 @@ func (db *DB) ListChannels(networkID int64) ([]Channel, error) {
 	return channels, nil
 }
 
-func (db *DB) GetChannel(networkID int64, name string) (*Channel, error) {
-	db.lock.RLock()
-	defer db.lock.RUnlock()
-
-	ch := &Channel{Name: name}
-
-	var key *string
-	row := db.db.QueryRow("SELECT id, key FROM Channel WHERE network = ? AND name = ?", networkID, name)
-	if err := row.Scan(&ch.ID, &key); err == sql.ErrNoRows {
-		return nil, ErrNoSuchChannel
-	} else if err != nil {
-		return nil, err
-	}
-	ch.Key = fromStringPtr(key)
-	return ch, nil
-}
-
 func (db *DB) StoreChannel(networkID int64, ch *Channel) error {
 	db.lock.Lock()
 	defer db.lock.Unlock()

upstream.go

@@ -421,13 +421,7 @@ func (uc *upstreamConn) handleMessage(msg *irc.Message) error {
 		uc.registered = true
 		uc.logger.Printf("connection registered")
 
-		channels, err := uc.srv.db.ListChannels(uc.network.ID)
-		if err != nil {
-			uc.logger.Printf("failed to list channels from database: %v", err)
-			break
-		}
-
-		for _, ch := range channels {
+		for _, ch := range uc.network.channels {
 			params := []string{ch.Name}
 			if ch.Key != "" {
 				params = append(params, ch.Key)

user.go

@@ -56,16 +56,23 @@ type network struct {
 	stopped chan struct{}
 
 	conn           *upstreamConn
+	channels       map[string]*Channel
 	history        map[string]*networkHistory // indexed by entity
 	offlineClients map[string]struct{}        // indexed by client name
 	lastError      error
 }
 
-func newNetwork(user *user, record *Network) *network {
+func newNetwork(user *user, record *Network, channels []Channel) *network {
+	m := make(map[string]*Channel, len(channels))
+	for _, ch := range channels {
+		m[ch.Name] = &ch
+	}
+
 	return &network{
 		Network:        *record,
 		user:           user,
 		stopped:        make(chan struct{}),
+		channels:       m,
 		history:        make(map[string]*networkHistory),
 		offlineClients: make(map[string]struct{}),
 	}
@@ -140,16 +147,22 @@ func (net *network) Stop() {
 }
 
 func (net *network) createUpdateChannel(ch *Channel) error {
-	if dbCh, err := net.user.srv.db.GetChannel(net.ID, ch.Name); err == nil {
-		ch.ID = dbCh.ID
-	} else if err != ErrNoSuchChannel {
+	if current, ok := net.channels[ch.Name]; ok {
+		ch.ID = current.ID // update channel if it already exists
+	}
+	if err := net.user.srv.db.StoreChannel(net.ID, ch); err != nil {
 		return err
 	}
-	return net.user.srv.db.StoreChannel(net.ID, ch)
+	net.channels[ch.Name] = ch
+	return nil
 }
 
 func (net *network) deleteChannel(name string) error {
-	return net.user.srv.db.DeleteChannel(net.ID, name)
+	if err := net.user.srv.db.DeleteChannel(net.ID, name); err != nil {
+		return err
+	}
+	delete(net.channels, name)
+	return nil
 }
 
 type user struct {
@@ -221,7 +234,12 @@ func (u *user) run() {
 	}
 
 	for _, record := range networks {
-		network := newNetwork(u, &record)
+		channels, err := u.srv.db.ListChannels(record.ID)
+		if err != nil {
+			u.srv.Logger.Printf("failed to list channels for user %q, network %q: %v", u.Username, record.GetName(), err)
+		}
+
+		network := newNetwork(u, &record, channels)
 		u.networks = append(u.networks, network)
 
 		go network.run()
@@ -353,7 +371,7 @@ func (u *user) createNetwork(net *Network) (*network, error) {
 		panic("tried creating an already-existing network")
 	}
 
-	network := newNetwork(u, net)
+	network := newNetwork(u, net, nil)
 	err := u.srv.db.StoreNetwork(u.Username, &network.Network)
 	if err != nil {
 		return nil, err