1 files changed, 136 insertions, 0 deletions
diff --git a/miner/unconfirmed.go b/miner/unconfirmed.go
new file mode 100644
index 0000000..3a176e8
--- /dev/null
+++ b/miner/unconfirmed.go
@@ -0,0 +1,136 @@
+// 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/log"
+)
+
+// chainRetriever is used by the unconfirmed block set to verify whether a previously
+// mined block is part of the canonical chain or not.
+type chainRetriever interface {
+	// GetHeaderByNumber retrieves the canonical header associated with a block number.
+	GetHeaderByNumber(number uint64) *types.Header
+
+	// GetBlockByNumber retrieves the canonical block associated with a block number.
+	GetBlockByNumber(number uint64) *types.Block
+}
+
+// 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 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 the canonical chain.
+type unconfirmedBlocks struct {
+	chain  chainRetriever // 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 chainRetriever, 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
+	log.Info("🔨 mined potential block", "number", index, "hash", hash)
+}
+
+// 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:
+			log.Warn("Failed to retrieve header of mined block", "number", next.index, "hash", next.hash)
+		case header.Hash() == next.hash:
+			log.Info("🔗 block reached canonical chain", "number", next.index, "hash", next.hash)
+		default:
+			// Block is not canonical, check whether we have an uncle or a lost block
+			included := false
+			for number := next.index; !included && number < next.index+uint64(set.depth) && number <= height; number++ {
+				if block := set.chain.GetBlockByNumber(number); block != nil {
+					for _, uncle := range block.Uncles() {
+						if uncle.Hash() == next.hash {
+							included = true
+							break
+						}
+					}
+				}
+			}
+			if included {
+				log.Info("⑂ block became an uncle", "number", next.index, "hash", next.hash)
+			} else {
+				log.Info("😱 block lost", "number", next.index, "hash", next.hash)
+			}
+		}
+		// 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)
+		}
+	}
+}