harness-drone/server/pubsub/pubsub.go

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package pubsub
import (
"sync"
)
type PubSub struct {
sync.Mutex
// In-memory list of all channels being managed by the broker.
channels map[interface{}]*Channel
}
// NewPubSub creates a new instance of the PubSub type
// and returns a pointer.
func NewPubSub() *PubSub {
return &PubSub{
channels: make(map[interface{}]*Channel),
}
}
// Lookup performs a thread safe operation to return a pointer
// to an existing Channel object with the given key. If the
// Channel does not exist a nil value is returned.
func (b *PubSub) Lookup(key interface{}) *Channel {
b.Lock()
defer b.Unlock()
// find the channel in the existing list
return b.channels[key]
}
// Register performs a thread safe operation to return a pointer
// to a Channel object for the given key. The Channel is created
// if it does not yet exist.
func (b *PubSub) Register(key interface{}) *Channel {
return b.RegisterOpts(key, DefaultOpts)
}
// Register performs a thread safe operation to return a pointer
// to a Channel object for the given key. The Channel is created
// if it does not yet exist using custom options.
func (b *PubSub) RegisterOpts(key interface{}, opts *Opts) *Channel {
b.Lock()
defer b.Unlock()
// find the channel in the existing list
c, ok := b.channels[key]
if ok {
return c
}
// create the channel and register
// with the pubsub server
c = NewChannel(opts)
b.channels[key] = c
go c.start()
return c
}
// Unregister performs a thread safe operation to delete the
// Channel with the given key.
func (b *PubSub) Unregister(key interface{}) {
b.Lock()
defer b.Unlock()
// find the channel in the existing list
c, ok := b.channels[key]
if !ok {
return
}
c.Close()
delete(b.channels, key)
return
}