github.com/aquanetwork/aquachain@v1.7.8/core/chain_makers.go

// Copyright 2015 The aquachain Authors
// This file is part of the aquachain library.
//
// The aquachain 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 aquachain 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 aquachain library. If not, see <http://www.gnu.org/licenses/>.

package core

import (
	"fmt"
	"math/big"

	"gitlab.com/aquachain/aquachain/aquadb"
	"gitlab.com/aquachain/aquachain/common"
	"gitlab.com/aquachain/aquachain/consensus"
	"gitlab.com/aquachain/aquachain/consensus/misc"
	"gitlab.com/aquachain/aquachain/core/state"
	"gitlab.com/aquachain/aquachain/core/types"
	"gitlab.com/aquachain/aquachain/core/vm"
	"gitlab.com/aquachain/aquachain/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)
}

// Setversion sets the header version
func (b *BlockGen) SetVersion(version params.HeaderVersion) {
	b.header.Version = version
}

// 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(), nil)
}

// 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 aquadb.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, nil, 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 the block and state according to any hard-fork specs
		if hf4 := config.GetHF(4); hf4 != nil && hf4.Cmp(b.header.Number) == 0 {
			misc.ApplyHardFork4(statedb)
		}
		if hf5 := config.GetHF(5); hf5 != nil && hf5.Cmp(b.header.Number) == 0 {
			misc.ApplyHardFork5(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
			root, err := statedb.Commit(config.IsEIP158(b.header.Number))
			if err != nil {
				panic(fmt.Sprintf("state write error: %v", err))
			}
			if err := statedb.Database().TrieDB().Commit(root, false); err != nil {
				panic(fmt.Sprintf("trie write error: %v", err))
			}
			return block, b.receipts
		}
		return nil, nil
	} // end of genblock()
	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 {
	if parent.Version() == 0 {
		parent.SetVersion(chain.Config().GetBlockVersion(parent.Number()))
	}
	var time *big.Int
	if parent.Time() == nil {
		time = big.NewInt(240)
	} else {
		time = new(big.Int).Add(parent.Time(), big.NewInt(240)) // block time is fixed at 10 seconds
	}
	num := new(big.Int).Add(parent.Number(), common.Big1)
	return &types.Header{
		Root:       state.IntermediateRoot(chain.Config().IsEIP158(num)),
		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(240)), // parent time
			Difficulty: parent.Difficulty(),
			UncleHash:  parent.UncleHash(),
		}, nil),
		GasLimit: CalcGasLimit(parent),
		Number:   num,
		Time:     time,
		Version:  chain.Config().GetBlockVersion(num),
	}
}

// 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) (aquadb.Database, *BlockChain, error) {
	// Initialize a fresh chain with only a genesis block
	gspec := new(Genesis)
	db := aquadb.NewMemDatabase()
	genesis := gspec.MustCommit(db)

	blockchain, _ := NewBlockChain(db, nil, params.AllAquahashProtocolChanges, 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 aquadb.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()
		headers[i].Version = params.TestChainConfig.GetBlockVersion(headers[i].Number)
	}
	return headers
}

// makeBlockChain creates a deterministic chain of blocks rooted at parent.
func makeBlockChain(parent *types.Block, n int, engine consensus.Engine, db aquadb.Database, seed int) []*types.Block {
	blocks, _ := GenerateChain(params.TestChainConfig, parent, engine, db, n, func(i int, b *BlockGen) {
		b.header.Version = b.config.GetBlockVersion(b.Number())
		b.SetCoinbase(common.Address{0: byte(seed), 19: byte(i)})
	})
	return blocks
}