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peerStrategyHelper.go
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/
peerStrategyHelper.go
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// ZooBC Copyright (C) 2020 Quasisoft Limited - Hong Kong
// This file is part of ZooBC <https://github.com/zoobc/zoobc-core>
//
// ZooBC is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// ZooBC 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with ZooBC. If not, see <http://www.gnu.org/licenses/>.
//
// Additional Permission Under GNU GPL Version 3 section 7.
// As the special exception permitted under Section 7b, c and e,
// in respect with the Author’s copyright, please refer to this section:
//
// 1. You are free to convey this Program according to GNU GPL Version 3,
// as long as you respect and comply with the Author’s copyright by
// showing in its user interface an Appropriate Notice that the derivate
// program and its source code are “powered by ZooBC”.
// This is an acknowledgement for the copyright holder, ZooBC,
// as the implementation of appreciation of the exclusive right of the
// creator and to avoid any circumvention on the rights under trademark
// law for use of some trade names, trademarks, or service marks.
//
// 2. Complying to the GNU GPL Version 3, you may distribute
// the program without any permission from the Author.
// However a prior notification to the authors will be appreciated.
//
// ZooBC is architected by Roberto Capodieci & Barton Johnston
// contact us at roberto.capodieci[at]blockchainzoo.com
// and barton.johnston[at]blockchainzoo.com
//
// Core developers that contributed to the current implementation of the
// software are:
// Ahmad Ali Abdilah ahmad.abdilah[at]blockchainzoo.com
// Allan Bintoro allan.bintoro[at]blockchainzoo.com
// Andy Herman
// Gede Sukra
// Ketut Ariasa
// Nawi Kartini nawi.kartini[at]blockchainzoo.com
// Stefano Galassi stefano.galassi[at]blockchainzoo.com
//
// IMPORTANT: The above copyright notice and this permission notice
// shall be included in all copies or substantial portions of the Software.
package strategy
import (
"github.com/zoobc/zoobc-core/common/model"
"github.com/zoobc/zoobc-core/common/util"
p2pUtil "github.com/zoobc/zoobc-core/p2p/util"
"sync"
)
type (
PeerStrategyHelperInterface interface {
GetRandomPeerWithoutRepetition(peers map[string]*model.Peer, mutex *sync.Mutex) *model.Peer
}
// PeerStrategyHelper helper functions shared by peer strategies
PeerStrategyHelper struct {
}
)
func NewPeerStrategyHelper() *PeerStrategyHelper {
return &PeerStrategyHelper{}
}
// GetRandomPeerWithoutRepetition get a random peer from a list. the returned peer is removed from the list (peer parameter) so that,
// when the function is called again, the same peer wont' be selected.
// NOTE: this function is thread-safe and can be used with concurrent goroutines
func (ps *PeerStrategyHelper) GetRandomPeerWithoutRepetition(peers map[string]*model.Peer, mutex *sync.Mutex) *model.Peer {
var (
peer *model.Peer
idx uint64
)
randomIdx := uint64(util.GetSecurePositiveRandom()) % uint64(len(peers))
for _, knownPeer := range peers {
if idx == randomIdx {
peer = knownPeer
break
}
idx++
}
mutex.Lock()
defer mutex.Unlock()
delete(peers, p2pUtil.GetFullAddressPeer(peer))
return peer
}