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package core
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/pow"
)
// FakePow is a non-validating proof of work implementation.
// It returns true from Verify for any block.
type FakePow struct{}
func (f FakePow) Search(block pow.Block, stop <-chan struct{}) (uint64, []byte) {
return 0, nil
}
func (f FakePow) Verify(block pow.Block) bool { return true }
func (f FakePow) GetHashrate() int64 { return 0 }
func (f FakePow) Turbo(bool) {}
// 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
header *types.Header
statedb *state.StateDB
coinbase *state.StateObject
txs []*types.Transaction
receipts []*types.Receipt
uncles []*types.Header
}
// SetCoinbase sets the coinbase of the generated block.
// It can be called at most once.
func (b *BlockGen) SetCoinbase(addr common.Address) {
if b.coinbase != 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.coinbase = b.statedb.GetOrNewStateObject(addr)
b.coinbase.SetGasLimit(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.coinbase == nil {
b.SetCoinbase(common.Address{})
}
_, gas, err := ApplyMessage(NewEnv(b.statedb, nil, tx, b.header), tx, b.coinbase)
if err != nil {
panic(err)
}
b.statedb.Update()
b.header.GasUsed.Add(b.header.GasUsed, gas)
receipt := types.NewReceipt(b.statedb.Root().Bytes(), b.header.GasUsed)
logs := b.statedb.GetLogs(tx.Hash())
receipt.SetLogs(logs)
receipt.Bloom = types.CreateBloom(types.Receipts{receipt})
b.txs = append(b.txs, tx)
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.HasAccount(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]
}
// 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 ChainManager requires use of FakePow or
// a similar non-validating proof of work implementation.
func GenerateChain(parent *types.Block, db common.Database, n int, gen func(int, *BlockGen)) []*types.Block {
statedb := state.New(parent.Root(), db)
blocks := make(types.Blocks, n)
genblock := func(i int, h *types.Header) *types.Block {
b := &BlockGen{parent: parent, i: i, chain: blocks, header: h, statedb: statedb}
if gen != nil {
gen(i, b)
}
AccumulateRewards(statedb, h, b.uncles)
statedb.Update()
h.Root = statedb.Root()
return types.NewBlock(h, b.txs, b.uncles, b.receipts)
}
for i := 0; i < n; i++ {
header := makeHeader(parent, statedb)
block := genblock(i, header)
block.Td = CalcTD(block, parent)
blocks[i] = block
parent = block
}
return blocks
}
func makeHeader(parent *types.Block, state *state.StateDB) *types.Header {
time := parent.Time() + 10 // block time is fixed at 10 seconds
return &types.Header{
Root: state.Root(),
ParentHash: parent.Hash(),
Coinbase: parent.Coinbase(),
Difficulty: CalcDifficulty(time, parent.Time(), parent.Difficulty()),
GasLimit: CalcGasLimit(parent),
GasUsed: new(big.Int),
Number: new(big.Int).Add(parent.Number(), common.Big1),
Time: uint64(time),
}
}
// newCanonical creates a new deterministic canonical chain by running
// InsertChain on the result of makeChain.
func newCanonical(n int, db common.Database) (*BlockProcessor, error) {
evmux := &event.TypeMux{}
chainman, _ := NewChainManager(GenesisBlock(0, db), db, db, FakePow{}, evmux)
bman := NewBlockProcessor(db, db, FakePow{}, chainman, evmux)
bman.bc.SetProcessor(bman)
parent := bman.bc.CurrentBlock()
if n == 0 {
return bman, nil
}
lchain := makeChain(parent, n, db, canonicalSeed)
_, err := bman.bc.InsertChain(lchain)
return bman, err
}
func makeChain(parent *types.Block, n int, db common.Database, seed int) []*types.Block {
return GenerateChain(parent, db, n, func(i int, b *BlockGen) {
b.SetCoinbase(common.Address{0: byte(seed), 19: byte(i)})
})
}
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