mining: Break dependency on block manager instance.

This modifies the block template generate for the mining code such that
it takes chain instance and params instead of requiring a fully
initialized blockManager instance.

Also, in preparation for being able to more easily separate the code, it
exposes and makes use of two new functions:
- BestSnapshot which returns the state snapshot from the underlying
  chain instance
- TxSource which returns the underlying transaction source

This is a step towards being able to separate the mining code into its
own package.  No functional change.

cpuminer.go

@@ -160,7 +160,7 @@ func (m *CPUMiner) submitBlock(block *btcutil.Block) bool {
 	// detected and all work on the stale block is halted to start work on
 	// a new block, but the check only happens periodically, so it is
 	// possible a block was found and submitted in between.
-	latestHash := m.g.blockManager.chain.BestSnapshot().Hash
+	latestHash := m.g.BestSnapshot().Hash
 	msgBlock := block.MsgBlock()
 	if !msgBlock.Header.PrevBlock.IsEqual(latestHash) {
 		minrLog.Debugf("Block submitted via CPU miner with previous "+
@@ -170,7 +170,7 @@ func (m *CPUMiner) submitBlock(block *btcutil.Block) bool {
 
 	// Process this block using the same rules as blocks coming from other
 	// nodes.  This will in turn relay it to the network like normal.
-	isOrphan, err := m.g.blockManager.ProcessBlock(block, blockchain.BFNone)
+	isOrphan, err := m.cfg.ProcessBlock(block, blockchain.BFNone)
 	if err != nil {
 		// Anything other than a rule violation is an unexpected error,
 		// so log that error as an internal error.
@@ -222,7 +222,7 @@ func (m *CPUMiner) solveBlock(msgBlock *wire.MsgBlock, blockHeight int32,
 
 	// Initial state.
 	lastGenerated := time.Now()
-	lastTxUpdate := m.g.txSource.LastUpdated()
+	lastTxUpdate := m.g.TxSource().LastUpdated()
 	hashesCompleted := uint64(0)
 
 	// Note that the entire extra nonce range is iterated and the offset is
@@ -248,7 +248,7 @@ func (m *CPUMiner) solveBlock(msgBlock *wire.MsgBlock, blockHeight int32,
 
 				// The current block is stale if the best block
 				// has changed.
-				best := m.g.blockManager.chain.BestSnapshot()
+				best := m.g.BestSnapshot()
 				if !header.PrevBlock.IsEqual(best.Hash) {
 					return false
 				}
@@ -257,7 +257,7 @@ func (m *CPUMiner) solveBlock(msgBlock *wire.MsgBlock, blockHeight int32,
 				// has been updated since the block template was
 				// generated and it has been at least one
 				// minute.
-				if lastTxUpdate != m.g.txSource.LastUpdated() &&
+				if lastTxUpdate != m.g.TxSource().LastUpdated() &&
 					time.Now().After(lastGenerated.Add(time.Minute)) {
 
 					return false
@@ -327,8 +327,8 @@ out:
 		// this would otherwise end up building a new block template on
 		// a block that is in the process of becoming stale.
 		m.submitBlockLock.Lock()
-		curHeight := m.g.blockManager.chain.BestSnapshot().Height
-		if curHeight != 0 && !m.g.blockManager.IsCurrent() {
+		curHeight := m.g.BestSnapshot().Height
+		if curHeight != 0 && !m.cfg.IsCurrent() {
 			m.submitBlockLock.Unlock()
 			time.Sleep(time.Second)
 			continue
@@ -594,7 +594,7 @@ func (m *CPUMiner) GenerateNBlocks(n uint32) ([]*chainhash.Hash, error) {
 		// be changing and this would otherwise end up building a new block
 		// template on a block that is in the process of becoming stale.
 		m.submitBlockLock.Lock()
-		curHeight := m.g.blockManager.chain.BestSnapshot().Height
+		curHeight := m.g.BestSnapshot().Height
 
 		// Choose a payment address at random.
 		rand.Seed(time.Now().UnixNano())

mining.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"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/mining"
@@ -311,11 +312,12 @@ func medianAdjustedTime(chainState *blockchain.BestState, timeSource blockchain.
 // See the NewBlockTemplate method for a detailed description of how the block
 // template is generated.
 type BlkTmplGenerator struct {
-	policy       *mining.Policy
-	txSource     mining.TxSource
-	sigCache     *txscript.SigCache
-	blockManager *blockManager
-	timeSource   blockchain.MedianTimeSource
+	policy      *mining.Policy
+	chainParams *chaincfg.Params
+	txSource    mining.TxSource
+	chain       *blockchain.BlockChain
+	timeSource  blockchain.MedianTimeSource
+	sigCache    *txscript.SigCache
 }
 
 // newBlkTmplGenerator returns a new block template generator for the given
@@ -324,16 +326,18 @@ type BlkTmplGenerator struct {
 // The additional state-related fields are required in order to ensure the
 // templates are built on top of the current best chain and adhere to the
 // consensus rules.
-func newBlkTmplGenerator(policy *mining.Policy, txSource mining.TxSource,
-	timeSource blockchain.MedianTimeSource, sigCache *txscript.SigCache,
-	blockManager *blockManager) *BlkTmplGenerator {
+func newBlkTmplGenerator(policy *mining.Policy, params *chaincfg.Params,
+	txSource mining.TxSource, chain *blockchain.BlockChain,
+	timeSource blockchain.MedianTimeSource,
+	sigCache *txscript.SigCache) *BlkTmplGenerator {
 
 	return &BlkTmplGenerator{
-		policy:       policy,
-		txSource:     txSource,
-		sigCache:     sigCache,
-		blockManager: blockManager,
-		timeSource:   timeSource,
+		policy:      policy,
+		chainParams: params,
+		txSource:    txSource,
+		chain:       chain,
+		timeSource:  timeSource,
+		sigCache:    sigCache,
 	}
 }
 
@@ -402,12 +406,11 @@ func newBlkTmplGenerator(policy *mining.Policy, txSource mining.TxSource,
 func (g *BlkTmplGenerator) NewBlockTemplate(payToAddress btcutil.Address) (*BlockTemplate, error) {
 	// Locals for faster access.
 	policy := g.policy
-	blockManager := g.blockManager
 	timeSource := g.timeSource
 	sigCache := g.sigCache
 
 	// Extend the most recently known best block.
-	best := blockManager.chain.BestSnapshot()
+	best := g.chain.BestSnapshot()
 	prevHash := best.Hash
 	nextBlockHeight := best.Height + 1
 
@@ -490,7 +493,7 @@ mempoolLoop:
 		// mempool since a transaction which depends on other
 		// transactions in the mempool must come after those
 		// dependencies in the final generated block.
-		utxos, err := blockManager.chain.FetchUtxoView(tx)
+		utxos, err := g.chain.FetchUtxoView(tx)
 		if err != nil {
 			minrLog.Warnf("Unable to fetch utxo view for tx %s: "+
 				"%v", tx.Hash(), err)
@@ -723,7 +726,7 @@ mempoolLoop:
 	// is potentially adjusted to ensure it comes after the median time of
 	// the last several blocks per the chain consensus rules.
 	ts := medianAdjustedTime(best, timeSource)
-	reqDifficulty, err := blockManager.chain.CalcNextRequiredDifficulty(ts)
+	reqDifficulty, err := g.chain.CalcNextRequiredDifficulty(ts)
 	if err != nil {
 		return nil, err
 	}
@@ -749,7 +752,7 @@ mempoolLoop:
 	// chain with no issues.
 	block := btcutil.NewBlock(&msgBlock)
 	block.SetHeight(nextBlockHeight)
-	if err := blockManager.chain.CheckConnectBlock(block); err != nil {
+	if err := g.chain.CheckConnectBlock(block); err != nil {
 		return nil, err
 	}
 
@@ -777,15 +780,13 @@ func (g *BlkTmplGenerator) UpdateBlockTime(msgBlock *wire.MsgBlock) error {
 	// The new timestamp is potentially adjusted to ensure it comes after
 	// the median time of the last several blocks per the chain consensus
 	// rules.
-	best := g.blockManager.chain.BestSnapshot()
-	newTimestamp := medianAdjustedTime(best, g.timeSource)
-	msgBlock.Header.Timestamp = newTimestamp
+	newTime := medianAdjustedTime(g.chain.BestSnapshot(), g.timeSource)
+	msgBlock.Header.Timestamp = newTime
 
 	// If running on a network that requires recalculating the difficulty,
 	// do so now.
 	if activeNetParams.ReduceMinDifficulty {
-		chain := g.blockManager.chain
-		difficulty, err := chain.CalcNextRequiredDifficulty(newTimestamp)
+		difficulty, err := g.chain.CalcNextRequiredDifficulty(newTime)
 		if err != nil {
 			return err
 		}
@@ -822,3 +823,20 @@ func (g *BlkTmplGenerator) UpdateExtraNonce(msgBlock *wire.MsgBlock, blockHeight
 	msgBlock.Header.MerkleRoot = *merkles[len(merkles)-1]
 	return nil
 }
+
+// BestSnapshot returns information about the current best chain block and
+// related state as of the current point in time using the chain instance
+// associated with the block template generator.  The returned state must be
+// treated as immutable since it is shared by all callers.
+//
+// This function is safe for concurrent access.
+func (g *BlkTmplGenerator) BestSnapshot() *blockchain.BestState {
+	return g.chain.BestSnapshot()
+}
+
+// TxSource returns the associated transaction source.
+//
+// This function is safe for concurrent access.
+func (g *BlkTmplGenerator) TxSource() mining.TxSource {
+	return g.txSource
+}

server.go

@@ -2380,8 +2380,8 @@ func newServer(listenAddrs []string, db database.DB, chainParams *chaincfg.Param
 		BlockPrioritySize: cfg.BlockPrioritySize,
 		TxMinFreeFee:      cfg.minRelayTxFee,
 	}
-	blockTemplateGenerator := newBlkTmplGenerator(&policy, s.txMemPool,
-		s.timeSource, s.sigCache, bm)
+	blockTemplateGenerator := newBlkTmplGenerator(&policy, s.chainParams,
+		s.txMemPool, s.blockManager.chain, s.timeSource, s.sigCache)
 	s.cpuMiner = newCPUMiner(&cpuminerConfig{
 		ChainParams:            chainParams,
 		BlockTemplateGenerator: blockTemplateGenerator,