mirror of https://github.com/ethereum/go-ethereum
parent
699243f8ae
commit
e7f2c8feb8
@ -0,0 +1,150 @@ |
|||||||
|
// Copyright 2023 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 ethclient |
||||||
|
|
||||||
|
import ( |
||||||
|
"context" |
||||||
|
"sync" |
||||||
|
"time" |
||||||
|
|
||||||
|
"github.com/ethereum/go-ethereum" |
||||||
|
"github.com/ethereum/go-ethereum/core/types" |
||||||
|
"github.com/ethereum/go-ethereum/event" |
||||||
|
"github.com/ethereum/go-ethereum/rpc" |
||||||
|
) |
||||||
|
|
||||||
|
// subscribeNewHeadPolling creates a block filter and polls it.
|
||||||
|
// This is the fallback for SubscribeNewHead on HTTP connections.
|
||||||
|
func (ec *Client) subscribeNewHeadPolling(ctx context.Context, ch chan<- *types.Header) (event.Subscription, error) { |
||||||
|
var id string |
||||||
|
err := ec.c.CallContext(ctx, &id, "eth_newBlockFilter") |
||||||
|
if err != nil { |
||||||
|
return nil, err |
||||||
|
} |
||||||
|
sub := newFilterSub(ec.c, id, ch) |
||||||
|
return sub, nil |
||||||
|
} |
||||||
|
|
||||||
|
// subscribeFilterLogs subscribes to a log filter.
|
||||||
|
// This is the fallback for SubscribeFilterLogs on HTTP connections.
|
||||||
|
func (ec *Client) subscribeFilterLogsPolling(ctx context.Context, q ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) { |
||||||
|
arg, err := toFilterArg(q) |
||||||
|
if err != nil { |
||||||
|
return nil, err |
||||||
|
} |
||||||
|
var id string |
||||||
|
err = ec.c.CallContext(ctx, &id, "eth_newFilter", arg) |
||||||
|
if err != nil { |
||||||
|
return nil, err |
||||||
|
} |
||||||
|
sub := newFilterSub(ec.c, id, ch) |
||||||
|
return sub, nil |
||||||
|
} |
||||||
|
|
||||||
|
// filterSub implements event.Subscription with the polling filter API.
|
||||||
|
type filterSub[Result any] struct { |
||||||
|
// The channel to send the results to
|
||||||
|
resultc chan<- Result |
||||||
|
errc chan error |
||||||
|
closed chan struct{} |
||||||
|
unsubOnce sync.Once |
||||||
|
|
||||||
|
id string |
||||||
|
client *rpc.Client |
||||||
|
} |
||||||
|
|
||||||
|
func newFilterSub[Result any](client *rpc.Client, id string, resultc chan<- Result) *filterSub[Result] { |
||||||
|
sub := &filterSub[Result]{ |
||||||
|
resultc: resultc, |
||||||
|
errc: make(chan error, 1), |
||||||
|
closed: make(chan struct{}), |
||||||
|
client: client, |
||||||
|
} |
||||||
|
go sub.poll() |
||||||
|
return sub |
||||||
|
} |
||||||
|
|
||||||
|
// Unsubscribe cancels the event subscription.
|
||||||
|
func (s *filterSub[Result]) Unsubscribe() { |
||||||
|
s.closeWithError(nil) |
||||||
|
} |
||||||
|
|
||||||
|
// Err returns the subscription error channel.
|
||||||
|
func (s *filterSub[Result]) Err() <-chan error { |
||||||
|
return s.errc |
||||||
|
} |
||||||
|
|
||||||
|
func (s *filterSub[Result]) poll() { |
||||||
|
var timer = time.NewTicker(10 * time.Second) |
||||||
|
for { |
||||||
|
err := s.getChanges() |
||||||
|
if err != nil { |
||||||
|
s.closeWithError(err) |
||||||
|
return |
||||||
|
} |
||||||
|
|
||||||
|
// Wait for next time.
|
||||||
|
select { |
||||||
|
case <-timer.C: |
||||||
|
case <-s.closed: |
||||||
|
return |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
func (s *filterSub[Result]) closeWithError(err error) { |
||||||
|
s.unsubOnce.Do(func() { |
||||||
|
close(s.closed) |
||||||
|
unsubErr := s.uninstallFilter() |
||||||
|
if unsubErr != nil && err == nil { |
||||||
|
err = unsubErr |
||||||
|
} |
||||||
|
if err != nil { |
||||||
|
select { |
||||||
|
case s.errc <- err: |
||||||
|
default: |
||||||
|
} |
||||||
|
} |
||||||
|
close(s.errc) |
||||||
|
}) |
||||||
|
} |
||||||
|
|
||||||
|
// getChanges calls eth_getFilterChanges and delivers the results.
|
||||||
|
func (s *filterSub[Result]) getChanges() error { |
||||||
|
ctx, done := context.WithTimeout(context.Background(), 10*time.Second) |
||||||
|
defer done() |
||||||
|
|
||||||
|
var results []Result |
||||||
|
err := s.client.CallContext(ctx, &results, "eth_getFilterChanges", s.id) |
||||||
|
if err != nil { |
||||||
|
return err |
||||||
|
} |
||||||
|
for _, result := range results { |
||||||
|
select { |
||||||
|
case s.resultc <- result: |
||||||
|
case <-s.closed: |
||||||
|
return nil |
||||||
|
} |
||||||
|
} |
||||||
|
return nil |
||||||
|
} |
||||||
|
|
||||||
|
// uninstallFilter removes the filter on the server side.
|
||||||
|
func (s *filterSub[Result]) uninstallFilter() error { |
||||||
|
ctx, done := context.WithTimeout(context.Background(), 10*time.Second) |
||||||
|
defer done() |
||||||
|
return s.client.CallContext(ctx, nil, "eth_uninstallFilter", s.id) |
||||||
|
} |
Loading…
Reference in new issue