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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package filter implements event filters.
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]
}
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