blockchain: Associate time src with chain instance.

Rather than making the caller to pass in the median time source on
ProcessBlock and IsCurrent, modify the Config struct to include the
median time source and associate it with the chain instance when it is
created.

This is being done because both the ProcessBlock and IsCurrent functions
require access to the blockchain state already, it is a little bit safer
to ensure the time source matches the chain instance state, it
simplifies the caller logic, and it also allows its use within the logic
of the blockchain package itself which will be required by upcoming
rule change warning logic that is part of BIP9.

blockchain/chain.go

@@ -164,6 +164,7 @@ type BlockChain struct {
 	checkpointsByHeight map[int32]*chaincfg.Checkpoint
 	db                  database.DB
 	chainParams         *chaincfg.Params
+	timeSource          MedianTimeSource
 	notifications       NotificationCallback
 	sigCache            *txscript.SigCache
 	indexManager        IndexManager
@@ -1331,7 +1332,7 @@ func (b *BlockChain) connectBestChain(node *blockNode, block *btcutil.Block, fla
 //  - Latest block has a timestamp newer than 24 hours ago
 //
 // This function is safe for concurrent access.
-func (b *BlockChain) IsCurrent(timeSource MedianTimeSource) bool {
+func (b *BlockChain) IsCurrent() bool {
 	b.chainLock.RLock()
 	defer b.chainLock.RUnlock()
 
@@ -1344,7 +1345,7 @@ func (b *BlockChain) IsCurrent(timeSource MedianTimeSource) bool {
 
 	// Not current if the latest best block has a timestamp before 24 hours
 	// ago.
-	minus24Hours := timeSource.AdjustedTime().Add(-24 * time.Hour)
+	minus24Hours := b.timeSource.AdjustedTime().Add(-24 * time.Hour)
 	if b.bestNode.timestamp.Before(minus24Hours) {
 		return false
 	}
@@ -1397,6 +1398,14 @@ type Config struct {
 	// This field is required.
 	ChainParams *chaincfg.Params
 
+	// TimeSource defines the median time source to use for things such as
+	// block processing and determining whether or not the chain is current.
+	//
+	// The caller is expected to keep a reference to the time source as well
+	// and add time samples from other peers on the network so the local
+	// time is adjusted to be in agreement with other peers.
+	TimeSource MedianTimeSource
+
 	// Notifications defines a callback to which notifications will be sent
 	// when various events take place.  See the documentation for
 	// Notification and NotificationType for details on the types and
@@ -1448,6 +1457,7 @@ func New(config *Config) (*BlockChain, error) {
 		checkpointsByHeight: checkpointsByHeight,
 		db:                  config.DB,
 		chainParams:         params,
+		timeSource:          config.TimeSource,
 		notifications:       config.Notifications,
 		sigCache:            config.SigCache,
 		indexManager:        config.IndexManager,

blockchain/chain_test.go

@@ -48,10 +48,8 @@ func TestHaveBlock(t *testing.T) {
 	chain.DisableCheckpoints(true)
 	blockchain.TstSetCoinbaseMaturity(1)
 
-	timeSource := blockchain.NewMedianTime()
 	for i := 1; i < len(blocks); i++ {
-		isOrphan, err := chain.ProcessBlock(blocks[i], timeSource,
-			blockchain.BFNone)
+		isOrphan, err := chain.ProcessBlock(blocks[i], blockchain.BFNone)
 		if err != nil {
 			t.Errorf("ProcessBlock fail on block %v: %v\n", i, err)
 			return
@@ -65,7 +63,7 @@ func TestHaveBlock(t *testing.T) {
 
 	// Insert an orphan block.
 	isOrphan, err := chain.ProcessBlock(btcutil.NewBlock(&Block100000),
-		timeSource, blockchain.BFNone)
+		blockchain.BFNone)
 	if err != nil {
 		t.Errorf("Unable to process block: %v", err)
 		return

blockchain/common_test.go

@@ -110,6 +110,7 @@ func chainSetup(dbName string) (*blockchain.BlockChain, func(), error) {
 	chain, err := blockchain.New(&blockchain.Config{
 		DB:          db,
 		ChainParams: &chaincfg.MainNetParams,
+		TimeSource:  blockchain.NewMedianTime(),
 	})
 	if err != nil {
 		teardown()

blockchain/example_test.go

@@ -41,27 +41,25 @@ func ExampleBlockChain_ProcessBlock() {
 	// Create a new BlockChain instance using the underlying database for
 	// the main bitcoin network.  This example does not demonstrate some
 	// of the other available configuration options such as specifying a
-	// notification callback and signature cache.
+	// notification callback and signature cache.  Also, the caller would
+	// ordinarily keep a reference to the median time source and add time
+	// values obtained from other peers on the network so the local time is
+	// adjusted to be in agreement with other peers.
 	chain, err := blockchain.New(&blockchain.Config{
 		DB:          db,
 		ChainParams: &chaincfg.MainNetParams,
+		TimeSource:  blockchain.NewMedianTime(),
 	})
 	if err != nil {
 		fmt.Printf("Failed to create chain instance: %v\n", err)
 		return
 	}
 
-	// Create a new median time source that is required by the upcoming
-	// call to ProcessBlock.  Ordinarily this would also add time values
-	// obtained from other peers on the network so the local time is
-	// adjusted to be in agreement with other peers.
-	timeSource := blockchain.NewMedianTime()
-
 	// Process a block.  For this example, we are going to intentionally
 	// cause an error by trying to process the genesis block which already
 	// exists.
 	genesisBlock := btcutil.NewBlock(chaincfg.MainNetParams.GenesisBlock)
-	isOrphan, err := chain.ProcessBlock(genesisBlock, timeSource, blockchain.BFNone)
+	isOrphan, err := chain.ProcessBlock(genesisBlock, blockchain.BFNone)
 	if err != nil {
 		fmt.Printf("Failed to process block: %v\n", err)
 		return

blockchain/process.go

@@ -125,7 +125,7 @@ func (b *BlockChain) processOrphans(hash *wire.ShaHash, flags BehaviorFlags) err
 // when the error is nil.
 //
 // This function is safe for concurrent access.
-func (b *BlockChain) ProcessBlock(block *btcutil.Block, timeSource MedianTimeSource, flags BehaviorFlags) (bool, error) {
+func (b *BlockChain) ProcessBlock(block *btcutil.Block, flags BehaviorFlags) (bool, error) {
 	b.chainLock.Lock()
 	defer b.chainLock.Unlock()
 
@@ -152,7 +152,7 @@ func (b *BlockChain) ProcessBlock(block *btcutil.Block, timeSource MedianTimeSou
 	}
 
 	// Perform preliminary sanity checks on the block and its transactions.
-	err = checkBlockSanity(block, b.chainParams.PowLimit, timeSource, flags)
+	err = checkBlockSanity(block, b.chainParams.PowLimit, b.timeSource, flags)
 	if err != nil {
 		return false, err
 	}

blockchain/reorganization_test.go

@@ -58,10 +58,9 @@ func TestReorganization(t *testing.T) {
 	chain.DisableCheckpoints(true)
 	blockchain.TstSetCoinbaseMaturity(1)
 
-	timeSource := blockchain.NewMedianTime()
 	expectedOrphans := map[int]struct{}{5: {}, 6: {}}
 	for i := 1; i < len(blocks); i++ {
-		isOrphan, err := chain.ProcessBlock(blocks[i], timeSource, blockchain.BFNone)
+		isOrphan, err := chain.ProcessBlock(blocks[i], blockchain.BFNone)
 		if err != nil {
 			t.Errorf("ProcessBlock fail on block %v: %v\n", i, err)
 			return

blockmanager.go

@@ -496,7 +496,7 @@ func (b *blockManager) handleTxMsg(tmsg *txMsg) {
 // current returns true if we believe we are synced with our peers, false if we
 // still have blocks to check
 func (b *blockManager) current() bool {
-	if !b.chain.IsCurrent(b.server.timeSource) {
+	if !b.chain.IsCurrent() {
 		return false
 	}
 
@@ -564,8 +564,7 @@ func (b *blockManager) handleBlockMsg(bmsg *blockMsg) {
 
 	// Process the block to include validation, best chain selection, orphan
 	// handling, etc.
-	isOrphan, err := b.chain.ProcessBlock(bmsg.block,
-		b.server.timeSource, behaviorFlags)
+	isOrphan, err := b.chain.ProcessBlock(bmsg.block, behaviorFlags)
 	if err != nil {
 		// When the error is a rule error, it means the block was simply
 		// rejected as opposed to something actually going wrong, so log
@@ -1121,7 +1120,7 @@ out:
 
 			case processBlockMsg:
 				isOrphan, err := b.chain.ProcessBlock(msg.block,
-					b.server.timeSource, msg.flags)
+					msg.flags)
 				if err != nil {
 					msg.reply <- processBlockResponse{
 						isOrphan: false,
@@ -1402,6 +1401,7 @@ func newBlockManager(s *server, indexManager blockchain.IndexManager) (*blockMan
 	bm.chain, err = blockchain.New(&blockchain.Config{
 		DB:            s.db,
 		ChainParams:   s.chainParams,
+		TimeSource:    s.timeSource,
 		Notifications: bm.handleNotifyMsg,
 		SigCache:      s.sigCache,
 		IndexManager:  indexManager,

cmd/addblock/import.go

@@ -32,7 +32,6 @@ type importResults struct {
 type blockImporter struct {
 	db                database.DB
 	chain             *blockchain.BlockChain
-	medianTime        blockchain.MedianTimeSource
 	r                 io.ReadSeeker
 	processQueue      chan []byte
 	doneChan          chan bool
@@ -129,8 +128,7 @@ func (bi *blockImporter) processBlock(serializedBlock []byte) (bool, error) {
 
 	// Ensure the blocks follows all of the chain rules and match up to the
 	// known checkpoints.
-	isOrphan, err := bi.chain.ProcessBlock(block, bi.medianTime,
-		blockchain.BFFastAdd)
+	isOrphan, err := bi.chain.ProcessBlock(block, blockchain.BFFastAdd)
 	if err != nil {
 		return false, err
 	}
@@ -329,6 +327,7 @@ func newBlockImporter(db database.DB, r io.ReadSeeker) (*blockImporter, error) {
 	chain, err := blockchain.New(&blockchain.Config{
 		DB:           db,
 		ChainParams:  activeNetParams,
+		TimeSource:   blockchain.NewMedianTime(),
 		IndexManager: indexManager,
 	})
 	if err != nil {
@@ -343,7 +342,6 @@ func newBlockImporter(db database.DB, r io.ReadSeeker) (*blockImporter, error) {
 		errChan:      make(chan error),
 		quit:         make(chan struct{}),
 		chain:        chain,
-		medianTime:   blockchain.NewMedianTime(),
 		lastLogTime:  time.Now(),
 	}, nil
 }