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- // Copyright (c) 2017 Shivaram Lingamneni <slingamn@cs.stanford.edu>
- // released under the MIT license
-
- package irc
-
- import (
- "sync"
- )
-
- type channelManagerEntry struct {
- channel *Channel
- // this is a refcount for joins, so we can avoid a race where we incorrectly
- // think the channel is empty (without holding a lock across the entire Channel.Join()
- // call)
- pendingJoins int
- }
-
- // ChannelManager keeps track of all the channels on the server,
- // providing synchronization for creation of new channels on first join,
- // cleanup of empty channels on last part, and renames.
- type ChannelManager struct {
- sync.RWMutex // tier 2
- chans map[string]*channelManagerEntry
- registeredChannels map[string]bool
- server *Server
- }
-
- // NewChannelManager returns a new ChannelManager.
- func (cm *ChannelManager) Initialize(server *Server) {
- cm.chans = make(map[string]*channelManagerEntry)
- cm.server = server
-
- if server.Config().Channels.Registration.Enabled {
- cm.loadRegisteredChannels()
- }
- }
-
- func (cm *ChannelManager) loadRegisteredChannels() {
- registeredChannels := cm.server.channelRegistry.AllChannels()
- cm.Lock()
- defer cm.Unlock()
- cm.registeredChannels = registeredChannels
- }
-
- // Get returns an existing channel with name equivalent to `name`, or nil
- func (cm *ChannelManager) Get(name string) (channel *Channel) {
- name, err := CasefoldChannel(name)
- if err == nil {
- cm.RLock()
- defer cm.RUnlock()
- entry := cm.chans[name]
- // if the channel is still loading, pretend we don't have it
- if entry != nil && entry.channel.IsLoaded() {
- return entry.channel
- }
- }
- return nil
- }
-
- // Join causes `client` to join the channel named `name`, creating it if necessary.
- func (cm *ChannelManager) Join(client *Client, name string, key string, isSajoin bool, rb *ResponseBuffer) error {
- server := client.server
- casefoldedName, err := CasefoldChannel(name)
- if err != nil || len(casefoldedName) > server.Limits().ChannelLen {
- return errNoSuchChannel
- }
-
- cm.Lock()
- entry := cm.chans[casefoldedName]
- if entry == nil {
- registered := cm.registeredChannels[casefoldedName]
- entry = &channelManagerEntry{
- channel: NewChannel(server, name, registered),
- pendingJoins: 0,
- }
- cm.chans[casefoldedName] = entry
- }
- entry.pendingJoins += 1
- channel := entry.channel
- cm.Unlock()
-
- channel.EnsureLoaded()
- channel.Join(client, key, isSajoin, rb)
-
- cm.maybeCleanup(channel, true)
-
- return nil
- }
-
- func (cm *ChannelManager) maybeCleanup(channel *Channel, afterJoin bool) {
- cm.Lock()
- defer cm.Unlock()
-
- nameCasefolded := channel.NameCasefolded()
- entry := cm.chans[nameCasefolded]
- if entry == nil || entry.channel != channel {
- return
- }
-
- if afterJoin {
- entry.pendingJoins -= 1
- }
- if entry.pendingJoins == 0 && entry.channel.IsClean() {
- delete(cm.chans, nameCasefolded)
- }
- }
-
- // Part parts `client` from the channel named `name`, deleting it if it's empty.
- func (cm *ChannelManager) Part(client *Client, name string, message string, rb *ResponseBuffer) error {
- var channel *Channel
-
- casefoldedName, err := CasefoldChannel(name)
- if err != nil {
- return errNoSuchChannel
- }
-
- cm.RLock()
- entry := cm.chans[casefoldedName]
- if entry != nil {
- channel = entry.channel
- }
- cm.RUnlock()
-
- if channel == nil {
- return errNoSuchChannel
- }
- channel.Part(client, message, rb)
- return nil
- }
-
- func (cm *ChannelManager) Cleanup(channel *Channel) {
- cm.maybeCleanup(channel, false)
- }
-
- func (cm *ChannelManager) SetRegistered(channelName string, account string) (err error) {
- var channel *Channel
- cfname, err := CasefoldChannel(channelName)
- if err != nil {
- return err
- }
-
- var entry *channelManagerEntry
-
- defer func() {
- if err == nil && channel != nil {
- // registration was successful: make the database reflect it
- err = channel.Store(IncludeAllChannelAttrs)
- }
- }()
-
- cm.Lock()
- defer cm.Unlock()
- entry = cm.chans[cfname]
- if entry == nil {
- return errNoSuchChannel
- }
- channel = entry.channel
- err = channel.SetRegistered(account)
- if err != nil {
- return err
- }
- cm.registeredChannels[cfname] = true
- return nil
- }
-
- func (cm *ChannelManager) SetUnregistered(channelName string, account string) (err error) {
- cfname, err := CasefoldChannel(channelName)
- if err != nil {
- return err
- }
-
- var info RegisteredChannel
-
- defer func() {
- if err == nil {
- err = cm.server.channelRegistry.Delete(info)
- }
- }()
-
- cm.Lock()
- defer cm.Unlock()
- entry := cm.chans[cfname]
- if entry == nil {
- return errNoSuchChannel
- }
- info = entry.channel.ExportRegistration(0)
- if info.Founder != account {
- return errChannelNotOwnedByAccount
- }
- entry.channel.SetUnregistered(account)
- delete(cm.registeredChannels, cfname)
- return nil
- }
-
- // Rename renames a channel (but does not notify the members)
- func (cm *ChannelManager) Rename(name string, newname string) (err error) {
- cfname, err := CasefoldChannel(name)
- if err != nil {
- return errNoSuchChannel
- }
-
- cfnewname, err := CasefoldChannel(newname)
- if err != nil {
- return errInvalidChannelName
- }
-
- var channel *Channel
- var info RegisteredChannel
- defer func() {
- if channel != nil && info.Founder != "" {
- channel.Store(IncludeAllChannelAttrs)
- // we just flushed the channel under its new name, therefore this delete
- // cannot be overwritten by a write to the old name:
- cm.server.channelRegistry.Delete(info)
- }
- }()
-
- cm.Lock()
- defer cm.Unlock()
-
- if cm.chans[cfnewname] != nil || cm.registeredChannels[cfnewname] {
- return errChannelNameInUse
- }
- entry := cm.chans[cfname]
- if entry == nil {
- return errNoSuchChannel
- }
- channel = entry.channel
- info = channel.ExportRegistration(IncludeInitial)
- delete(cm.chans, cfname)
- cm.chans[cfnewname] = entry
- if cm.registeredChannels[cfname] {
- delete(cm.registeredChannels, cfname)
- cm.registeredChannels[cfnewname] = true
- }
- entry.channel.Rename(newname, cfnewname)
- return nil
- }
-
- // Len returns the number of channels
- func (cm *ChannelManager) Len() int {
- cm.RLock()
- defer cm.RUnlock()
- return len(cm.chans)
- }
-
- // Channels returns a slice containing all current channels
- func (cm *ChannelManager) Channels() (result []*Channel) {
- cm.RLock()
- defer cm.RUnlock()
- result = make([]*Channel, 0, len(cm.chans))
- for _, entry := range cm.chans {
- if entry.channel.IsLoaded() {
- result = append(result, entry.channel)
- }
- }
- return
- }
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