Merge pull request #3430 from karalabe/miner-pending-race

miner: clean up unconfirmed mined block tracking

3 files changed, 217 insertions, 74 deletions

diff --git a/miner/unconfirmed.go b/miner/unconfirmed.go
new file mode 100644
index 000000000..86a30de35
--- /dev/null
+++ b/miner/unconfirmed.go
@@ -0,0 +1,118 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package miner
+
+import (
+	"container/ring"
+	"sync"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+)
+
+// headerRetriever is used by the unconfirmed block set to verify whether a previously
+// mined block is part of the canonical chain or not.
+type headerRetriever interface {
+	// GetHeaderByNumber retrieves the canonical header associated with a block number.
+	GetHeaderByNumber(number uint64) *types.Header
+}
+
+// unconfirmedBlock is a small collection of metadata about a locally mined block
+// that is placed into a unconfirmed set for canonical chain inclusion tracking.
+type unconfirmedBlock struct {
+	index uint64
+	hash  common.Hash
+}
+
+// unconfirmedBlocks implements a data structure to maintain locally mined blocks
+// have have not yet reached enough maturity to guarantee chain inclusion. It is
+// used by the miner to provide logs to the user when a previously mined block
+// has a high enough guarantee to not be reorged out of te canonical chain.
+type unconfirmedBlocks struct {
+	chain  headerRetriever // Blockchain to verify canonical status through
+	depth  uint            // Depth after which to discard previous blocks
+	blocks *ring.Ring      // Block infos to allow canonical chain cross checks
+	lock   sync.RWMutex    // Protects the fields from concurrent access
+}
+
+// newUnconfirmedBlocks returns new data structure to track currently unconfirmed blocks.
+func newUnconfirmedBlocks(chain headerRetriever, depth uint) *unconfirmedBlocks {
+	return &unconfirmedBlocks{
+		chain: chain,
+		depth: depth,
+	}
+}
+
+// Insert adds a new block to the set of unconfirmed ones.
+func (set *unconfirmedBlocks) Insert(index uint64, hash common.Hash) {
+	// If a new block was mined locally, shift out any old enough blocks
+	set.Shift(index)
+
+	// Create the new item as its own ring
+	item := ring.New(1)
+	item.Value = &unconfirmedBlock{
+		index: index,
+		hash:  hash,
+	}
+	// Set as the initial ring or append to the end
+	set.lock.Lock()
+	defer set.lock.Unlock()
+
+	if set.blocks == nil {
+		set.blocks = item
+	} else {
+		set.blocks.Move(-1).Link(item)
+	}
+	// Display a log for the user to notify of a new mined block unconfirmed
+	glog.V(logger.Info).Infof("🔨  mined potential block #%d [%x…], waiting for %d blocks to confirm", index, hash.Bytes()[:4], set.depth)
+}
+
+// Shift drops all unconfirmed blocks from the set which exceed the unconfirmed sets depth
+// allowance, checking them against the canonical chain for inclusion or staleness
+// report.
+func (set *unconfirmedBlocks) Shift(height uint64) {
+	set.lock.Lock()
+	defer set.lock.Unlock()
+
+	for set.blocks != nil {
+		// Retrieve the next unconfirmed block and abort if too fresh
+		next := set.blocks.Value.(*unconfirmedBlock)
+		if next.index+uint64(set.depth) > height {
+			break
+		}
+		// Block seems to exceed depth allowance, check for canonical status
+		header := set.chain.GetHeaderByNumber(next.index)
+		switch {
+		case header == nil:
+			glog.V(logger.Warn).Infof("failed to retrieve header of mined block #%d [%x…]", next.index, next.hash.Bytes()[:4])
+		case header.Hash() == next.hash:
+			glog.V(logger.Info).Infof("🔗  mined block #%d [%x…] reached canonical chain", next.index, next.hash.Bytes()[:4])
+		default:
+			glog.V(logger.Info).Infof("⑂ mined block #%d [%x…] became a side fork", next.index, next.hash.Bytes()[:4])
+		}
+		// Drop the block out of the ring
+		if set.blocks.Value == set.blocks.Next().Value {
+			set.blocks = nil
+		} else {
+			set.blocks = set.blocks.Move(-1)
+			set.blocks.Unlink(1)
+			set.blocks = set.blocks.Move(1)
+		}
+	}
+}
diff --git a/miner/unconfirmed_test.go b/miner/unconfirmed_test.go
new file mode 100644
index 000000000..456af1764
--- /dev/null
+++ b/miner/unconfirmed_test.go
@@ -0,0 +1,85 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package miner
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+// noopHeaderRetriever is an implementation of headerRetriever that always
+// returns nil for any requested headers.
+type noopHeaderRetriever struct{}
+
+func (r *noopHeaderRetriever) GetHeaderByNumber(number uint64) *types.Header {
+	return nil
+}
+
+// Tests that inserting blocks into the unconfirmed set accumulates them until
+// the desired depth is reached, after which they begin to be dropped.
+func TestUnconfirmedInsertBounds(t *testing.T) {
+	limit := uint(10)
+
+	pool := newUnconfirmedBlocks(new(noopHeaderRetriever), limit)
+	for depth := uint64(0); depth < 2*uint64(limit); depth++ {
+		// Insert multiple blocks for the same level just to stress it
+		for i := 0; i < int(depth); i++ {
+			pool.Insert(depth, common.Hash([32]byte{byte(depth), byte(i)}))
+		}
+		// Validate that no blocks below the depth allowance are left in
+		pool.blocks.Do(func(block interface{}) {
+			if block := block.(*unconfirmedBlock); block.index+uint64(limit) <= depth {
+				t.Errorf("depth %d: block %x not dropped", depth, block.hash)
+			}
+		})
+	}
+}
+
+// Tests that shifting blocks out of the unconfirmed set works both for normal
+// cases as well as for corner cases such as empty sets, empty shifts or full
+// shifts.
+func TestUnconfirmedShifts(t *testing.T) {
+	// Create a pool with a few blocks on various depths
+	limit, start := uint(10), uint64(25)
+
+	pool := newUnconfirmedBlocks(new(noopHeaderRetriever), limit)
+	for depth := start; depth < start+uint64(limit); depth++ {
+		pool.Insert(depth, common.Hash([32]byte{byte(depth)}))
+	}
+	// Try to shift below the limit and ensure no blocks are dropped
+	pool.Shift(start + uint64(limit) - 1)
+	if n := pool.blocks.Len(); n != int(limit) {
+		t.Errorf("unconfirmed count mismatch: have %d, want %d", n, limit)
+	}
+	// Try to shift half the blocks out and verify remainder
+	pool.Shift(start + uint64(limit) - 1 + uint64(limit/2))
+	if n := pool.blocks.Len(); n != int(limit)/2 {
+		t.Errorf("unconfirmed count mismatch: have %d, want %d", n, limit/2)
+	}
+	// Try to shift all the remaining blocks out and verify emptyness
+	pool.Shift(start + 2*uint64(limit))
+	if n := pool.blocks.Len(); n != 0 {
+		t.Errorf("unconfirmed count mismatch: have %d, want %d", n, 0)
+	}
+	// Try to shift out from the empty set and make sure it doesn't break
+	pool.Shift(start + 3*uint64(limit))
+	if n := pool.blocks.Len(); n != 0 {
+		t.Errorf("unconfirmed count mismatch: have %d, want %d", n, 0)
+	}
+}
diff --git a/miner/worker.go b/miner/worker.go
index fdc6b7d8e..f29566c0a 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -55,26 +55,20 @@ type Agent interface {
 	GetHashRate() int64
 }
 
-type uint64RingBuffer struct {
-	ints []uint64 //array of all integers in buffer
-	next int      //where is the next insertion? assert 0 <= next < len(ints)
-}
-
 // Work is the workers current environment and holds
 // all of the current state information
 type Work struct {
 	config *params.ChainConfig
 	signer types.Signer
 
-	state            *state.StateDB // apply state changes here
-	ancestors        *set.Set       // ancestor set (used for checking uncle parent validity)
-	family           *set.Set       // family set (used for checking uncle invalidity)
-	uncles           *set.Set       // uncle set
-	tcount           int            // tx count in cycle
-	ownedAccounts    *set.Set
-	lowGasTxs        types.Transactions
-	failedTxs        types.Transactions
-	localMinedBlocks *uint64RingBuffer // the most recent block numbers that were mined locally (used to check block inclusion)
+	state         *state.StateDB // apply state changes here
+	ancestors     *set.Set       // ancestor set (used for checking uncle parent validity)
+	family        *set.Set       // family set (used for checking uncle invalidity)
+	uncles        *set.Set       // uncle set
+	tcount        int            // tx count in cycle
+	ownedAccounts *set.Set
+	lowGasTxs     types.Transactions
+	failedTxs     types.Transactions
 
 	Block *types.Block // the new block
 
@@ -123,6 +117,8 @@ type worker struct {
 	txQueueMu sync.Mutex
 	txQueue   map[common.Hash]*types.Transaction
 
+	unconfirmed *unconfirmedBlocks // set of locally mined blocks pending canonicalness confirmations
+
 	// atomic status counters
 	mining int32
 	atWork int32
@@ -144,6 +140,7 @@ func newWorker(config *params.ChainConfig, coinbase common.Address, eth Backend,
 		coinbase:       coinbase,
 		txQueue:        make(map[common.Hash]*types.Transaction),
 		agents:         make(map[Agent]struct{}),
+		unconfirmed:    newUnconfirmedBlocks(eth.BlockChain(), 5),
 		fullValidation: false,
 	}
 	worker.events = worker.mux.Subscribe(core.ChainHeadEvent{}, core.ChainSideEvent{}, core.TxPreEvent{})
@@ -269,18 +266,6 @@ func (self *worker) update() {
 	}
 }
 
-func newLocalMinedBlock(blockNumber uint64, prevMinedBlocks *uint64RingBuffer) (minedBlocks *uint64RingBuffer) {
-	if prevMinedBlocks == nil {
-		minedBlocks = &uint64RingBuffer{next: 0, ints: make([]uint64, miningLogAtDepth+1)}
-	} else {
-		minedBlocks = prevMinedBlocks
-	}
-
-	minedBlocks.ints[minedBlocks.next] = blockNumber
-	minedBlocks.next = (minedBlocks.next + 1) % len(minedBlocks.ints)
-	return minedBlocks
-}
-
 func (self *worker) wait() {
 	for {
 		mustCommitNewWork := true
@@ -355,17 +340,8 @@ func (self *worker) wait() {
 					}
 				}(block, work.state.Logs(), work.receipts)
 			}
-
-			// check staleness and display confirmation
-			var stale, confirm string
-			canonBlock := self.chain.GetBlockByNumber(block.NumberU64())
-			if canonBlock != nil && canonBlock.Hash() != block.Hash() {
-				stale = "stale "
-			} else {
-				confirm = "Wait 5 blocks for confirmation"
-				work.localMinedBlocks = newLocalMinedBlock(block.Number().Uint64(), work.localMinedBlocks)
-			}
-			glog.V(logger.Info).Infof("🔨  Mined %sblock (#%v / %x). %s", stale, block.Number(), block.Hash().Bytes()[:4], confirm)
+			// Insert the block into the set of pending ones to wait for confirmations
+			self.unconfirmed.Insert(block.NumberU64(), block.Hash())
 
 			if mustCommitNewWork {
 				self.commitNewWork()
@@ -417,9 +393,6 @@ func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error
 	// Keep track of transactions which return errors so they can be removed
 	work.tcount = 0
 	work.ownedAccounts = accountAddressesSet(accounts)
-	if self.current != nil {
-		work.localMinedBlocks = self.current.localMinedBlocks
-	}
 	self.current = work
 	return nil
 }
@@ -435,38 +408,6 @@ func (w *worker) setGasPrice(p *big.Int) {
 	w.mux.Post(core.GasPriceChanged{Price: w.gasPrice})
 }
 
-func (self *worker) isBlockLocallyMined(current *Work, deepBlockNum uint64) bool {
-	//Did this instance mine a block at {deepBlockNum} ?
-	var isLocal = false
-	for idx, blockNum := range current.localMinedBlocks.ints {
-		if deepBlockNum == blockNum {
-			isLocal = true
-			current.localMinedBlocks.ints[idx] = 0 //prevent showing duplicate logs
-			break
-		}
-	}
-	//Short-circuit on false, because the previous and following tests must both be true
-	if !isLocal {
-		return false
-	}
-
-	//Does the block at {deepBlockNum} send earnings to my coinbase?
-	var block = self.chain.GetBlockByNumber(deepBlockNum)
-	return block != nil && block.Coinbase() == self.coinbase
-}
-
-func (self *worker) logLocalMinedBlocks(current, previous *Work) {
-	if previous != nil && current.localMinedBlocks != nil {
-		nextBlockNum := current.Block.NumberU64()
-		for checkBlockNum := previous.Block.NumberU64(); checkBlockNum < nextBlockNum; checkBlockNum++ {
-			inspectBlockNum := checkBlockNum - miningLogAtDepth
-			if self.isBlockLocallyMined(current, inspectBlockNum) {
-				glog.V(logger.Info).Infof("🔨 🔗  Mined %d blocks back: block #%v", miningLogAtDepth, inspectBlockNum)
-			}
-		}
-	}
-}
-
 func (self *worker) commitNewWork() {
 	self.mu.Lock()
 	defer self.mu.Unlock()
@@ -513,7 +454,6 @@ func (self *worker) commitNewWork() {
 			}
 		}
 	}
-	previous := self.current
 	// Could potentially happen if starting to mine in an odd state.
 	err := self.makeCurrent(parent, header)
 	if err != nil {
@@ -574,7 +514,7 @@ func (self *worker) commitNewWork() {
 	// We only care about logging if we're actually mining.
 	if atomic.LoadInt32(&self.mining) == 1 {
 		glog.V(logger.Info).Infof("commit new work on block %v with %d txs & %d uncles. Took %v\n", work.Block.Number(), work.tcount, len(uncles), time.Since(tstart))
-		self.logLocalMinedBlocks(work, previous)
+		self.unconfirmed.Shift(work.Block.NumberU64() - 1)
 	}
 	self.push(work)
 }