source: code/trunk/bridge.go@ 789

package soju

import (
        "context"
        "fmt"
        "strconv"
        "strings"

        "gopkg.in/irc.v3"
)

func forwardChannel(ctx context.Context, dc *downstreamConn, ch *upstreamChannel) {
        if !ch.complete {
                panic("Tried to forward a partial channel")
        }

        // RPL_NOTOPIC shouldn't be sent on JOIN
        if ch.Topic != "" {
                sendTopic(dc, ch)
        }

        if dc.caps["soju.im/read"] {
                channelCM := ch.conn.network.casemap(ch.Name)
                r, err := dc.srv.db.GetReadReceipt(ctx, ch.conn.network.ID, channelCM)
                if err != nil {
                        dc.logger.Printf("failed to get the read receipt for %q: %v", ch.Name, err)
                } else {
                        timestampStr := "*"
                        if r != nil {
                                timestampStr = fmt.Sprintf("timestamp=%s", formatServerTime(r.Timestamp))
                        }
                        dc.SendMessage(&irc.Message{
                                Prefix:  dc.prefix(),
                                Command: "READ",
                                Params:  []string{dc.marshalEntity(ch.conn.network, ch.Name), timestampStr},
                        })
                }
        }

        sendNames(dc, ch)
}

func sendTopic(dc *downstreamConn, ch *upstreamChannel) {
        downstreamName := dc.marshalEntity(ch.conn.network, ch.Name)

        if ch.Topic != "" {
                dc.SendMessage(&irc.Message{
                        Prefix:  dc.srv.prefix(),
                        Command: irc.RPL_TOPIC,
                        Params:  []string{dc.nick, downstreamName, ch.Topic},
                })
                if ch.TopicWho != nil {
                        topicWho := dc.marshalUserPrefix(ch.conn.network, ch.TopicWho)
                        topicTime := strconv.FormatInt(ch.TopicTime.Unix(), 10)
                        dc.SendMessage(&irc.Message{
                                Prefix:  dc.srv.prefix(),
                                Command: rpl_topicwhotime,
                                Params:  []string{dc.nick, downstreamName, topicWho.String(), topicTime},
                        })
                }
        } else {
                dc.SendMessage(&irc.Message{
                        Prefix:  dc.srv.prefix(),
                        Command: irc.RPL_NOTOPIC,
                        Params:  []string{dc.nick, downstreamName, "No topic is set"},
                })
        }
}

func sendNames(dc *downstreamConn, ch *upstreamChannel) {
        downstreamName := dc.marshalEntity(ch.conn.network, ch.Name)

        emptyNameReply := &irc.Message{
                Prefix:  dc.srv.prefix(),
                Command: irc.RPL_NAMREPLY,
                Params:  []string{dc.nick, string(ch.Status), downstreamName, ""},
        }
        maxLength := maxMessageLength - len(emptyNameReply.String())

        var buf strings.Builder
        for _, entry := range ch.Members.innerMap {
                nick := entry.originalKey
                memberships := entry.value.(*memberships)
                s := memberships.Format(dc) + dc.marshalEntity(ch.conn.network, nick)

                n := buf.Len() + 1 + len(s)
                if buf.Len() != 0 && n > maxLength {
                        // There's not enough space for the next space + nick.
                        dc.SendMessage(&irc.Message{
                                Prefix:  dc.srv.prefix(),
                                Command: irc.RPL_NAMREPLY,
                                Params:  []string{dc.nick, string(ch.Status), downstreamName, buf.String()},
                        })
                        buf.Reset()
                }

                if buf.Len() != 0 {
                        buf.WriteByte(' ')
                }
                buf.WriteString(s)
        }

        if buf.Len() != 0 {
                dc.SendMessage(&irc.Message{
                        Prefix:  dc.srv.prefix(),
                        Command: irc.RPL_NAMREPLY,
                        Params:  []string{dc.nick, string(ch.Status), downstreamName, buf.String()},
                })
        }

        dc.SendMessage(&irc.Message{
                Prefix:  dc.srv.prefix(),
                Command: irc.RPL_ENDOFNAMES,
                Params:  []string{dc.nick, downstreamName, "End of /NAMES list"},
        })
}