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-rw-r--r--eth/gasprice/gasprice.go189
1 files changed, 189 insertions, 0 deletions
diff --git a/eth/gasprice/gasprice.go b/eth/gasprice/gasprice.go
new file mode 100644
index 0000000..9b632c2
--- /dev/null
+++ b/eth/gasprice/gasprice.go
@@ -0,0 +1,189 @@
+// Copyright 2015 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 gasprice
+
+import (
+ "context"
+ "math/big"
+ "sort"
+ "sync"
+
+ "github.com/ava-labs/coreth/internal/ethapi"
+ "github.com/ava-labs/coreth/params"
+ "github.com/ava-labs/coreth/rpc"
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/core/types"
+)
+
+var maxPrice = big.NewInt(500 * params.GWei)
+
+type Config struct {
+ Blocks int
+ Percentile int
+ Default *big.Int `toml:",omitempty"`
+}
+
+// Oracle recommends gas prices based on the content of recent
+// blocks. Suitable for both light and full clients.
+type Oracle struct {
+ backend ethapi.Backend
+ lastHead common.Hash
+ lastPrice *big.Int
+ cacheLock sync.RWMutex
+ fetchLock sync.Mutex
+
+ checkBlocks, maxEmpty, maxBlocks int
+ percentile int
+}
+
+// NewOracle returns a new oracle.
+func NewOracle(backend ethapi.Backend, params Config) *Oracle {
+ blocks := params.Blocks
+ if blocks < 1 {
+ blocks = 1
+ }
+ percent := params.Percentile
+ if percent < 0 {
+ percent = 0
+ }
+ if percent > 100 {
+ percent = 100
+ }
+ return &Oracle{
+ backend: backend,
+ lastPrice: params.Default,
+ checkBlocks: blocks,
+ maxEmpty: blocks / 2,
+ maxBlocks: blocks * 5,
+ percentile: percent,
+ }
+}
+
+// SuggestPrice returns the recommended gas price.
+func (gpo *Oracle) SuggestPrice(ctx context.Context) (*big.Int, error) {
+ gpo.cacheLock.RLock()
+ lastHead := gpo.lastHead
+ lastPrice := gpo.lastPrice
+ gpo.cacheLock.RUnlock()
+
+ head, _ := gpo.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
+ headHash := head.Hash()
+ if headHash == lastHead {
+ return lastPrice, nil
+ }
+
+ gpo.fetchLock.Lock()
+ defer gpo.fetchLock.Unlock()
+
+ // try checking the cache again, maybe the last fetch fetched what we need
+ gpo.cacheLock.RLock()
+ lastHead = gpo.lastHead
+ lastPrice = gpo.lastPrice
+ gpo.cacheLock.RUnlock()
+ if headHash == lastHead {
+ return lastPrice, nil
+ }
+
+ blockNum := head.Number.Uint64()
+ ch := make(chan getBlockPricesResult, gpo.checkBlocks)
+ sent := 0
+ exp := 0
+ var blockPrices []*big.Int
+ for sent < gpo.checkBlocks && blockNum > 0 {
+ go gpo.getBlockPrices(ctx, types.MakeSigner(gpo.backend.ChainConfig(), big.NewInt(int64(blockNum))), blockNum, ch)
+ sent++
+ exp++
+ blockNum--
+ }
+ maxEmpty := gpo.maxEmpty
+ for exp > 0 {
+ res := <-ch
+ if res.err != nil {
+ return lastPrice, res.err
+ }
+ exp--
+ if res.price != nil {
+ blockPrices = append(blockPrices, res.price)
+ continue
+ }
+ if maxEmpty > 0 {
+ maxEmpty--
+ continue
+ }
+ if blockNum > 0 && sent < gpo.maxBlocks {
+ go gpo.getBlockPrices(ctx, types.MakeSigner(gpo.backend.ChainConfig(), big.NewInt(int64(blockNum))), blockNum, ch)
+ sent++
+ exp++
+ blockNum--
+ }
+ }
+ price := lastPrice
+ if len(blockPrices) > 0 {
+ sort.Sort(bigIntArray(blockPrices))
+ price = blockPrices[(len(blockPrices)-1)*gpo.percentile/100]
+ }
+ if price.Cmp(maxPrice) > 0 {
+ price = new(big.Int).Set(maxPrice)
+ }
+
+ gpo.cacheLock.Lock()
+ gpo.lastHead = headHash
+ gpo.lastPrice = price
+ gpo.cacheLock.Unlock()
+ return price, nil
+}
+
+type getBlockPricesResult struct {
+ price *big.Int
+ err error
+}
+
+type transactionsByGasPrice []*types.Transaction
+
+func (t transactionsByGasPrice) Len() int { return len(t) }
+func (t transactionsByGasPrice) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
+func (t transactionsByGasPrice) Less(i, j int) bool { return t[i].GasPrice().Cmp(t[j].GasPrice()) < 0 }
+
+// getBlockPrices calculates the lowest transaction gas price in a given block
+// and sends it to the result channel. If the block is empty, price is nil.
+func (gpo *Oracle) getBlockPrices(ctx context.Context, signer types.Signer, blockNum uint64, ch chan getBlockPricesResult) {
+ block, err := gpo.backend.BlockByNumber(ctx, rpc.BlockNumber(blockNum))
+ if block == nil {
+ ch <- getBlockPricesResult{nil, err}
+ return
+ }
+
+ blockTxs := block.Transactions()
+ txs := make([]*types.Transaction, len(blockTxs))
+ copy(txs, blockTxs)
+ sort.Sort(transactionsByGasPrice(txs))
+
+ for _, tx := range txs {
+ sender, err := types.Sender(signer, tx)
+ if err == nil && sender != block.Coinbase() {
+ ch <- getBlockPricesResult{tx.GasPrice(), nil}
+ return
+ }
+ }
+ ch <- getBlockPricesResult{nil, nil}
+}
+
+type bigIntArray []*big.Int
+
+func (s bigIntArray) Len() int { return len(s) }
+func (s bigIntArray) Less(i, j int) bool { return s[i].Cmp(s[j]) < 0 }
+func (s bigIntArray) Swap(i, j int) { s[i], s[j] = s[j], s[i] }