netsync: Initialize netsync package.

Create doc.go, interface.go, and README for new package.

netsync/README.md

@@ -0,0 +1,25 @@
+netsync
+=======
+
+[![Build Status](http://img.shields.io/travis/btcsuite/btcd.svg)](https://travis-ci.org/btcsuite/btcd)
+[![ISC License](http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org)
+[![GoDoc](https://img.shields.io/badge/godoc-reference-blue.svg)](http://godoc.org/github.com/btcsuite/btcd/netsync)
+
+## Overview
+
+This package implements a concurrency safe block syncing protocol. The provided
+implementation of SyncManager communicates with connected peers to perform an
+initial block download, keep the chain in sync, and announce new blocks
+connected to the chain. Currently the sync manager selects a single sync peer
+that it downloads all blocks from until it is up to date with the longest chain
+the sync peer is aware of.
+
+## Installation and Updating
+
+```bash
+$ go get -u github.com/btcsuite/btcd/netsync
+```
+
+## License
+
+Package netsync is licensed under the [copyfree](http://copyfree.org) ISC License.

netsync/blocklogger.go

@@ -1,4 +1,8 @@
-package main
+// Copyright (c) 2015-2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package netsync
 
 import (
 	"sync"

netsync/doc.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+/*
+The netsync package implements a concurrency safe block syncing protocol. The
+provided implementation of SyncManager communicates with connected peers to
+perform an initial block download, keep the chain and mempool in sync, and
+announce new blocks connected to the chain. Currently the block manager selects
+a single sync peer that it downloads all blocks from until it is up to date with
+the longest chain the sync peer is aware of.
+*/
+package netsync

netsync/interface.go

@@ -0,0 +1,94 @@
+// Copyright (c) 2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package netsync
+
+import (
+	"github.com/btcsuite/btcd/blockchain"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
+	"github.com/btcsuite/btcd/mempool"
+	"github.com/btcsuite/btcd/peer"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/btcsuite/btcutil"
+)
+
+// PeerNotifier exposes methods to notify peers of status changes to
+// transactions, blocks, etc. Currently server (in the main package) implements
+// this interface.
+type PeerNotifier interface {
+	AnnounceNewTransactions(newTxs []*mempool.TxDesc)
+
+	UpdatePeerHeights(latestBlkHash *chainhash.Hash, latestHeight int32, updateSource *peer.Peer)
+
+	RelayInventory(invVect *wire.InvVect, data interface{})
+
+	TransactionConfirmed(tx *btcutil.Tx)
+}
+
+// Config is a configuration struct used to initialize a new SyncManager.
+type Config struct {
+	PeerNotifier PeerNotifier
+	Chain        *blockchain.BlockChain
+	TxMemPool    *mempool.TxPool
+	ChainParams  *chaincfg.Params
+
+	DisableCheckpoints bool
+	MaxPeers           int
+}
+
+// SyncManager is the interface used to communicate block related messages with
+// peers. The SyncManager is started as by executing Start() in a goroutine.
+// Once started, it selects peers to sync from and starts the initial block
+// download. Once the chain is in sync, the SyncManager handles incoming block
+// and header notifications and relays announcements of new blocks to peers.
+type SyncManager interface {
+	// NewPeer informs the SyncManager of a newly active peer.
+	NewPeer(p *peer.Peer)
+
+	// QueueTx adds the passed transaction message and peer to the block
+	// handling queue.
+	QueueTx(tx *btcutil.Tx, p *peer.Peer, done chan struct{})
+
+	// QueueBlock adds the passed block message and peer to the block handling
+	// queue.
+	QueueBlock(block *btcutil.Block, p *peer.Peer, done chan struct{})
+
+	// QueueInv adds the passed inv message and peer to the block handling
+	// queue.
+	QueueInv(inv *wire.MsgInv, p *peer.Peer)
+
+	// QueueHeaders adds the passed headers message and peer to the block
+	// handling queue.
+	QueueHeaders(headers *wire.MsgHeaders, p *peer.Peer)
+
+	// DonePeer informs the SyncManager that a peer has disconnected.
+	DonePeer(p *peer.Peer)
+
+	// Start begins the core block handler which processes block and inv
+	// messages.
+	Start()
+
+	// Stop gracefully shuts down the SyncManager by stopping all asynchronous
+	// handlers and waiting for them to finish.
+	Stop() error
+
+	// SyncPeerID returns the ID of the current sync peer, or 0 if there is
+	// none.
+	SyncPeerID() int32
+
+	// ProcessBlock makes use of ProcessBlock on an internal instance of a block
+	// chain.
+	ProcessBlock(block *btcutil.Block, flags blockchain.BehaviorFlags) (bool, error)
+
+	// IsCurrent returns whether or not the SyncManager believes it is synced
+	// with the connected peers.
+	IsCurrent() bool
+
+	// Pause pauses the SyncManager until the returned channel is closed.
+	//
+	// Note that while paused, all peer and block processing is halted.  The
+	// message sender should avoid pausing the SyncManager for long durations.
+	Pause() chan<- struct{}
+}

netsync/manager.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
-package main
+package netsync
 
 import (
 	"container/list"
@@ -134,30 +134,6 @@ type headerNode struct {
 	hash   *chainhash.Hash
 }
 
-// PeerNotifier exposes methods to notify peers of status changes to
-// transactions, blocks, etc. Currently server implements this interface.
-type PeerNotifier interface {
-	AnnounceNewTransactions(newTxs []*mempool.TxDesc)
-
-	UpdatePeerHeights(latestBlkHash *chainhash.Hash, latestHeight int32, updateSource *peerpkg.Peer)
-
-	RelayInventory(invVect *wire.InvVect, data interface{})
-
-	TransactionConfirmed(tx *btcutil.Tx)
-}
-
-// blockManangerConfig is a configuration struct used to initialize a new
-// blockManager.
-type blockManagerConfig struct {
-	PeerNotifier PeerNotifier
-	Chain        *blockchain.BlockChain
-	TxMemPool    *mempool.TxPool
-	ChainParams  *chaincfg.Params
-
-	DisableCheckpoints bool
-	MaxPeers           int
-}
-
 // peerSyncState stores additional information that the blockManager tracks
 // about a peer.
 type peerSyncState struct {