// 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 core
import (
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/consensus/misc"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/params"
)
// So we can deterministically seed different blockchains
var (
canonicalSeed = 1
forkSeed = 2
)
// BlockGen creates blocks for testing.
// See GenerateChain for a detailed explanation.
type BlockGen struct {
i int
parent *types.Block
chain []*types.Block
chainReader consensus.ChainReader
header *types.Header
statedb *state.StateDB
gasPool *GasPool
txs []*types.Transaction
receipts []*types.Receipt
uncles []*types.Header
config *params.ChainConfig
engine consensus.Engine
}
// SetCoinbase sets the coinbase of the generated block.
// It can be called at most once.
func (b *BlockGen) SetCoinbase(addr common.Address) {
if b.gasPool != nil {
if len(b.txs) > 0 {
panic("coinbase must be set before adding transactions")
}
panic("coinbase can only be set once")
}
b.header.Coinbase = addr
b.gasPool = new(GasPool).AddGas(b.header.GasLimit)
}
// SetExtra sets the extra data field of the generated block.
func (b *BlockGen) SetExtra(data []byte) {
b.header.Extra = data
}
// AddTx adds a transaction to the generated block. If no coinbase has
// been set, the block's coinbase is set to the zero address.
//
// AddTx panics if the transaction cannot be executed. In addition to
// the protocol-imposed limitations (gas limit, etc.), there are some
// further limitations on the content of transactions that can be
// added. Notably, contract code relying on the BLOCKHASH instruction
// will panic during execution.
func (b *BlockGen) AddTx(tx *types.Transaction) {
if b.gasPool == nil {
b.SetCoinbase(common.Address{})
}
b.statedb.Prepare(tx.Hash(), common.Hash{}, len(b.txs))
receipt, _, err := ApplyTransaction(b.config, nil, &b.header.Coinbase, b.gasPool, b.statedb, b.header, tx, b.header.GasUsed, vm.Config{})
if err != nil {
panic(err)
}
b.txs = append(b.txs, tx)
b.receipts = append(b.receipts, receipt)
}
// Number returns the block number of the block being generated.
func (b *BlockGen) Number() *big.Int {
return new(big.Int).Set(b.header.Number)
}
// AddUncheckedReceipt forcefully adds a receipts to the block without a
// backing transaction.
//
// AddUncheckedReceipt will cause consensus failures when used during real
// chain processing. This is best used in conjunction with raw block insertion.
func (b *BlockGen) AddUncheckedReceipt(receipt *types.Receipt) {
b.receipts = append(b.receipts, receipt)
}
// TxNonce returns the next valid transaction nonce for the
// account at addr. It panics if the account does not exist.
func (b *BlockGen) TxNonce(addr common.Address) uint64 {
if !b.statedb.Exist(addr) {
panic("account does not exist")
}
return b.statedb.GetNonce(addr)
}
// AddUncle adds an uncle header to the generated block.
func (b *BlockGen) AddUncle(h *types.Header) {
b.uncles = append(b.uncles, h)
}
// PrevBlock returns a previously generated block by number. It panics if
// num is greater or equal to the number of the block being generated.
// For index -1, PrevBlock returns the parent block given to GenerateChain.
func (b *BlockGen) PrevBlock(index int) *types.Block {
if index >= b.i {
panic("block index out of range")
}
if index == -1 {
return b.parent
}
return b.chain[index]
}
// OffsetTime modifies the time instance of a block, implicitly changing its
// associated difficulty. It's useful to test scenarios where forking is not
// tied to chain length directly.
func (b *BlockGen) OffsetTime(seconds int64) {
b.header.Time.Add(b.header.Time, new(big.Int).SetInt64(seconds))
if b.header.Time.Cmp(b.parent.Header().Time) <= 0 {
panic("block time out of range")
}
b.header.Difficulty = b.engine.CalcDifficulty(b.chainReader, b.header.Time.Uint64(), b.parent.Header())
}
// GenerateChain creates a chain of n blocks. The first block's
// parent will be the provided parent. db is used to store
// intermediate states and should contain the parent's state trie.
//
// The generator function is called with a new block generator for
// every block. Any transactions and uncles added to the generator
// become part of the block. If gen is nil, the blocks will be empty
// and their coinbase will be the zero address.
//
// Blocks created by GenerateChain do not contain valid proof of work
// values. Inserting them into BlockChain requires use of FakePow or
// a similar non-validating proof of work implementation.
func GenerateChain(config *params.ChainConfig, parent *types.Block, engine consensus.Engine, db ethdb.Database, n int, gen func(int, *BlockGen)) ([]*types.Block, []types.Receipts) {
if config == nil {
config = params.TestChainConfig
}
blocks, receipts := make(types.Blocks, n), make([]types.Receipts, n)
genblock := func(i int, parent *types.Block, statedb *state.StateDB) (*types.Block, types.Receipts) {
// TODO(karalabe): This is needed for clique, which depends on multiple blocks.
// It's nonetheless ugly to spin up a blockchain here. Get rid of this somehow.
blockchain, _ := NewBlockChain(db, config, engine, vm.Config{})
defer blockchain.Stop()
b := &BlockGen{i: i, parent: parent, chain: blocks, chainReader: blockchain, statedb: statedb, config: config, engine: engine}
b.header = makeHeader(b.chainReader, parent, statedb, b.engine)
// Mutate the state and block according to any hard-fork specs
if daoBlock := config.DAOForkBlock; daoBlock != nil {
limit := new(big.Int).Add(daoBlock, params.DAOForkExtraRange)
if b.header.Number.Cmp(daoBlock) >= 0 && b.header.Number.Cmp(limit) < 0 {
if config.DAOForkSupport {
b.header.Extra = common.CopyBytes(params.DAOForkBlockExtra)
}
}
}
if config.DAOForkSupport && config.DAOForkBlock != nil && config.DAOForkBlock.Cmp(b.header.Number) == 0 {
misc.ApplyDAOHardFork(statedb)
}
// Execute any user modifications to the block and finalize it
if gen != nil {
gen(i, b)
}
if b.engine != nil {
block, _ := b.engine.Finalize(b.chainReader, b.header, statedb, b.txs, b.uncles, b.receipts)
// Write state changes to db
_, err := statedb.CommitTo(db, config.IsEIP158(b.header.Number))
if err != nil {
panic(fmt.Sprintf("state write error: %v", err))
}
return block, b.receipts
}
return nil, nil
}
for i := 0; i < n; i++ {
statedb, err := state.New(parent.Root(), state.NewDatabase(db))
if err != nil {
panic(err)
}
block, receipt := genblock(i, parent, statedb)
blocks[i] = block
receipts[i] = receipt
parent = block
}
return blocks, receipts
}
func makeHeader(chain consensus.ChainReader, parent *types.Block, state *state.StateDB, engine consensus.Engine) *types.Header {
var time *big.Int
if parent.Time() == nil {
time = big.NewInt(10)
} else {
time = new(big.Int).Add(parent.Time(), big.NewInt(10)) // block time is fixed at 10 seconds
}
return &types.Header{
Root: state.IntermediateRoot(chain.Config().IsEIP158(parent.Number())),
ParentHash: parent.Hash(),
Coinbase: parent.Coinbase(),
Difficulty: engine.CalcDifficulty(chain, time.Uint64(), &types.Header{
Number: parent.Number(),
Time: new(big.Int).Sub(time, big.NewInt(10)),
Difficulty: parent.Difficulty(),
UncleHash: parent.UncleHash(),
}),
GasLimit: CalcGasLimit(parent),
GasUsed: new(big.Int),
Number: new(big.Int).Add(parent.Number(), common.Big1),
Time: time,
}
}
// newCanonical creates a chain database, and injects a deterministic canonical
// chain. Depending on the full flag, if creates either a full block chain or a
// header only chain.
func newCanonical(engine consensus.Engine, n int, full bool) (ethdb.Database, *BlockChain, error) {
// Initialize a fresh chain with only a genesis block
gspec := new(Genesis)
db, _ := ethdb.NewMemDatabase()
genesis := gspec.MustCommit(db)
blockchain, _ := NewBlockChain(db, params.AllEthashProtocolChanges, engine, vm.Config{})
// Create and inject the requested chain
if n == 0 {
return db, blockchain, nil
}
if full {
// Full block-chain requested
blocks := makeBlockChain(genesis, n, engine, db, canonicalSeed)
_, err := blockchain.InsertChain(blocks)
return db, blockchain, err
}
// Header-only chain requested
headers := makeHeaderChain(genesis.Header(), n, engine, db, canonicalSeed)
_, err := blockchain.InsertHeaderChain(headers, 1)
return db, blockchain, err
}
// makeHeaderChain creates a deterministic chain of headers rooted at parent.
func makeHeaderChain(parent *types.Header, n int, engine consensus.Engine, db ethdb.Database, seed int) []*types.Header {
blocks := makeBlockChain(types.NewBlockWithHeader(parent), n, engine, db, seed)
headers := make([]*types.Header, len(blocks))
for i, block := range blocks {
headers[i] = block.Header()
}
return headers
}
// makeBlockChain creates a deterministic chain of blocks rooted at parent.
func makeBlockChain(parent *types.Block, n int, engine consensus.Engine, db ethdb.Database, seed int) []*types.Block {
blocks, _ := GenerateChain(params.TestChainConfig, parent, engine, db, n, func(i int, b *BlockGen) {
b.SetCoinbase(common.Address{0: byte(seed), 19: byte(i)})
})
return blocks
}
