github.com/arieschain/arieschain@v0.0.0-20191023063405-37c074544356/event/filter/filter.go (about)

     1  // Package filter implements event filters.
     2  package filter
     3  
     4  import "reflect"
     5  
     6  type Filter interface {
     7  	Compare(Filter) bool
     8  	Trigger(data interface{})
     9  }
    10  
    11  type FilterEvent struct {
    12  	filter Filter
    13  	data   interface{}
    14  }
    15  
    16  type Filters struct {
    17  	id       int
    18  	watchers map[int]Filter
    19  	ch       chan FilterEvent
    20  
    21  	quit chan struct{}
    22  }
    23  
    24  func New() *Filters {
    25  	return &Filters{
    26  		ch:       make(chan FilterEvent),
    27  		watchers: make(map[int]Filter),
    28  		quit:     make(chan struct{}),
    29  	}
    30  }
    31  
    32  func (self *Filters) Start() {
    33  	go self.loop()
    34  }
    35  
    36  func (self *Filters) Stop() {
    37  	close(self.quit)
    38  }
    39  
    40  func (self *Filters) Notify(filter Filter, data interface{}) {
    41  	self.ch <- FilterEvent{filter, data}
    42  }
    43  
    44  func (self *Filters) Install(watcher Filter) int {
    45  	self.watchers[self.id] = watcher
    46  	self.id++
    47  
    48  	return self.id - 1
    49  }
    50  
    51  func (self *Filters) Uninstall(id int) {
    52  	delete(self.watchers, id)
    53  }
    54  
    55  func (self *Filters) loop() {
    56  out:
    57  	for {
    58  		select {
    59  		case <-self.quit:
    60  			break out
    61  		case event := <-self.ch:
    62  			for _, watcher := range self.watchers {
    63  				if reflect.TypeOf(watcher) == reflect.TypeOf(event.filter) {
    64  					if watcher.Compare(event.filter) {
    65  						watcher.Trigger(event.data)
    66  					}
    67  				}
    68  			}
    69  		}
    70  	}
    71  }
    72  
    73  func (self *Filters) Match(a, b Filter) bool {
    74  	return reflect.TypeOf(a) == reflect.TypeOf(b) && a.Compare(b)
    75  }
    76  
    77  func (self *Filters) Get(i int) Filter {
    78  	return self.watchers[i]
    79  }