c213fd1fd8
There is no need to depend on the old context package now that the minimum Go version is 1.7. The move to "context" eliminates our weird vendoring setup. Some vendored code still uses golang.org/x/net/context and it is now vendored in the normal way. This change triggered new vet checks around context.WithTimeout which didn't fire with golang.org/x/net/context.
85 lines
2.7 KiB
Go
85 lines
2.7 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package les
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import (
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"context"
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"time"
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"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/eth/downloader"
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"github.com/ethereum/go-ethereum/light"
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)
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const (
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//forceSyncCycle = 10 * time.Second // Time interval to force syncs, even if few peers are available
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minDesiredPeerCount = 5 // Amount of peers desired to start syncing
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)
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// syncer is responsible for periodically synchronising with the network, both
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// downloading hashes and blocks as well as handling the announcement handler.
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func (pm *ProtocolManager) syncer() {
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// Start and ensure cleanup of sync mechanisms
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//pm.fetcher.Start()
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//defer pm.fetcher.Stop()
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defer pm.downloader.Terminate()
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// Wait for different events to fire synchronisation operations
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//forceSync := time.Tick(forceSyncCycle)
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for {
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select {
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case <-pm.newPeerCh:
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/* // Make sure we have peers to select from, then sync
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if pm.peers.Len() < minDesiredPeerCount {
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break
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}
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go pm.synchronise(pm.peers.BestPeer())
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*/
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/*case <-forceSync:
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// Force a sync even if not enough peers are present
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go pm.synchronise(pm.peers.BestPeer())
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*/
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case <-pm.noMorePeers:
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return
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}
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}
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}
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func (pm *ProtocolManager) needToSync(peerHead blockInfo) bool {
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head := pm.blockchain.CurrentHeader()
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currentTd := core.GetTd(pm.chainDb, head.Hash(), head.Number.Uint64())
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return currentTd != nil && peerHead.Td.Cmp(currentTd) > 0
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}
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// synchronise tries to sync up our local block chain with a remote peer.
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func (pm *ProtocolManager) synchronise(peer *peer) {
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// Short circuit if no peers are available
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if peer == nil {
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return
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}
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// Make sure the peer's TD is higher than our own.
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if !pm.needToSync(peer.headBlockInfo()) {
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return
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}
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ctx, cancel := context.WithTimeout(context.Background(), time.Second*5)
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defer cancel()
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pm.blockchain.(*light.LightChain).SyncCht(ctx)
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pm.downloader.Synchronise(peer.id, peer.Head(), peer.Td(), downloader.LightSync)
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}
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