go-ricochet/connection/channelmanager.go

115 lines
3.8 KiB
Go

package connection
import (
"errors"
"github.com/s-rah/go-ricochet/channels"
)
// ChannelManager encapsulates the logic for server and client side assignment
// and removal of channels.
type ChannelManager struct {
channels map[int32]*channels.Channel
nextFreeChannel int32
isClient bool
}
// NewClientChannelManager construsts a new channel manager enforcing behaviour
// of a ricochet client
func NewClientChannelManager() *ChannelManager {
channelManager := new(ChannelManager)
channelManager.channels = make(map[int32]*channels.Channel)
channelManager.nextFreeChannel = 1
channelManager.isClient = true
return channelManager
}
// NewServerChannelManager construsts a new channel manager enforcing behaviour
// from a ricochet server
func NewServerChannelManager() *ChannelManager {
channelManager := new(ChannelManager)
channelManager.channels = make(map[int32]*channels.Channel)
channelManager.nextFreeChannel = 2
channelManager.isClient = false
return channelManager
}
// OpenChannelRequest constructs a channel type ready for processing given a request
// from the client.
func (cm *ChannelManager) OpenChannelRequest(chandler channels.Handler) (*channels.Channel, error) {
// Some channels only allow us to open one of them per connection
if chandler.Singleton() && cm.Channel(chandler.Type(), channels.Outbound) != nil {
return nil, errors.New("Connection already has channel of type " + chandler.Type())
}
channel := new(channels.Channel)
channel.ID = cm.nextFreeChannel
cm.nextFreeChannel += 2
channel.Type = chandler.Type()
channel.Handler = &chandler
channel.Pending = true
channel.Direction = channels.Outbound
cm.channels[channel.ID] = channel
return channel, nil
}
// OpenChannelRequestFromPeer constructs a channel type ready for processing given a request
// from the remote peer.
func (cm *ChannelManager) OpenChannelRequestFromPeer(channelID int32, chandler channels.Handler) (*channels.Channel, error) {
if cm.isClient && (channelID%2) != 0 {
// Server is trying to open odd numbered channels
return nil, errors.New("server may only open even numbered channels")
} else if !cm.isClient && (channelID%2) == 0 {
// Server is trying to open odd numbered channels
return nil, errors.New("client may only open odd numbered channels")
}
_, exists := cm.channels[channelID]
if exists {
return nil, errors.New("channel id is already in use")
}
// Some channels only allow us to open one of them per connection
if chandler.Singleton() && cm.Channel(chandler.Type(), channels.Inbound) != nil {
return nil, errors.New("Connection already has channel of type " + chandler.Type())
}
channel := new(channels.Channel)
channel.ID = channelID
channel.Type = chandler.Type()
channel.Handler = &chandler
channel.Pending = true
channel.Direction = channels.Inbound
cm.channels[channelID] = channel
return channel, nil
}
// Channel finds an open or pending `type` channel in the direction `way` (Inbound
// or Outbound), and returns the associated state. Returns nil if no matching channel
// exists or if multiple matching channels exist.
func (cm *ChannelManager) Channel(ctype string, way channels.Direction) *channels.Channel {
var foundChannel *channels.Channel
for _, channel := range cm.channels {
if (*channel.Handler).Type() == ctype && channel.Direction == way {
if foundChannel == nil {
foundChannel = channel
} else {
// we have found multiple channels.
return nil
}
}
}
return foundChannel
}
// GetChannel finds and returns a given channel if it is found
func (cm *ChannelManager) GetChannel(channelID int32) (*channels.Channel, bool) {
channel, found := cm.channels[channelID]
return channel, found
}
// RemoveChannel removes a given channel id.
func (cm *ChannelManager) RemoveChannel(channelID int32) {
delete(cm.channels, channelID)
}