mirror of
https://gitlab.com/pulsechaincom/erigon-pulse.git
synced 2024-12-21 19:20:39 +00:00
0be3044b7e
* rename * rename "make grpc" * rename "abi bindings templates" * rename "abi bindings templates"
129 lines
3.2 KiB
Go
129 lines
3.2 KiB
Go
// Copyright 2016 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 event_test
|
|
|
|
import (
|
|
"fmt"
|
|
"sync"
|
|
|
|
"github.com/ledgerwatch/erigon/event"
|
|
)
|
|
|
|
// This example demonstrates how SubscriptionScope can be used to control the lifetime of
|
|
// subscriptions.
|
|
//
|
|
// Our example program consists of two servers, each of which performs a calculation when
|
|
// requested. The servers also allow subscribing to results of all computations.
|
|
type divServer struct{ results event.Feed }
|
|
type mulServer struct{ results event.Feed }
|
|
|
|
func (s *divServer) do(a, b int) int {
|
|
r := a / b
|
|
s.results.Send(r)
|
|
return r
|
|
}
|
|
|
|
func (s *mulServer) do(a, b int) int {
|
|
r := a * b
|
|
s.results.Send(r)
|
|
return r
|
|
}
|
|
|
|
// The servers are contained in an App. The app controls the servers and exposes them
|
|
// through its API.
|
|
type App struct {
|
|
divServer
|
|
mulServer
|
|
scope event.SubscriptionScope
|
|
}
|
|
|
|
func (s *App) Calc(op byte, a, b int) int {
|
|
switch op {
|
|
case '/':
|
|
return s.divServer.do(a, b)
|
|
case '*':
|
|
return s.mulServer.do(a, b)
|
|
default:
|
|
panic("invalid op")
|
|
}
|
|
}
|
|
|
|
// The app's SubscribeResults method starts sending calculation results to the given
|
|
// channel. Subscriptions created through this method are tied to the lifetime of the App
|
|
// because they are registered in the scope.
|
|
func (s *App) SubscribeResults(op byte, ch chan<- int) event.Subscription {
|
|
switch op {
|
|
case '/':
|
|
return s.scope.Track(s.divServer.results.Subscribe(ch))
|
|
case '*':
|
|
return s.scope.Track(s.mulServer.results.Subscribe(ch))
|
|
default:
|
|
panic("invalid op")
|
|
}
|
|
}
|
|
|
|
// Stop stops the App, closing all subscriptions created through SubscribeResults.
|
|
func (s *App) Stop() {
|
|
s.scope.Close()
|
|
}
|
|
|
|
func ExampleSubscriptionScope() {
|
|
// Create the app.
|
|
var (
|
|
app App
|
|
wg sync.WaitGroup
|
|
divs = make(chan int)
|
|
muls = make(chan int)
|
|
)
|
|
|
|
// Run a subscriber in the background.
|
|
divsub := app.SubscribeResults('/', divs)
|
|
mulsub := app.SubscribeResults('*', muls)
|
|
wg.Add(1)
|
|
go func() {
|
|
defer wg.Done()
|
|
defer fmt.Println("subscriber exited")
|
|
defer divsub.Unsubscribe()
|
|
defer mulsub.Unsubscribe()
|
|
for {
|
|
select {
|
|
case result := <-divs:
|
|
fmt.Println("division happened:", result)
|
|
case result := <-muls:
|
|
fmt.Println("multiplication happened:", result)
|
|
case <-divsub.Err():
|
|
return
|
|
case <-mulsub.Err():
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
|
|
// Interact with the app.
|
|
app.Calc('/', 22, 11)
|
|
app.Calc('*', 3, 4)
|
|
|
|
// Stop the app. This shuts down the subscriptions, causing the subscriber to exit.
|
|
app.Stop()
|
|
wg.Wait()
|
|
|
|
// Output:
|
|
// division happened: 2
|
|
// multiplication happened: 12
|
|
// subscriber exited
|
|
}
|