path: root/event/filter/filter.go

package filter

import "reflect"

type Filter interface {
    Compare(Filter) bool
    Trigger(data interface{})
}

type FilterEvent struct {
    filter Filter
    data   interface{}
}

type Filters struct {
    id       int
    watchers map[int]Filter
    ch       chan FilterEvent

    quit chan struct{}
}

func New() *Filters {
    return &Filters{
        ch:       make(chan FilterEvent),
        watchers: make(map[int]Filter),
        quit:     make(chan struct{}),
    }
}

func (self *Filters) Start() {
    go self.loop()
}

func (self *Filters) Stop() {
    close(self.quit)
}

func (self *Filters) Notify(filter Filter, data interface{}) {
    self.ch <- FilterEvent{filter, data}
}

func (self *Filters) Install(watcher Filter) int {
    self.watchers[self.id] = watcher
    self.id++

    return self.id - 1
}

func (self *Filters) Uninstall(id int) {
    delete(self.watchers, id)
}

func (self *Filters) loop() {
out:
    for {
        select {
        case <-self.quit:
            break out
        case event := <-self.ch:
            for _, watcher := range self.watchers {
                if reflect.TypeOf(watcher) == reflect.TypeOf(event.filter) {
                    if watcher.Compare(event.filter) {
                        watcher.Trigger(event.data)
                    }
                }
            }
        }
    }
}

func (self *Filters) Match(a, b Filter) bool {
    return reflect.TypeOf(a) == reflect.TypeOf(b) && a.Compare(b)
}

func (self *Filters) Get(i int) Filter {
    return self.watchers[i]
}