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// 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/consensus/ethash"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/params"
)
func ExampleGenerateChain() {
var (
key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
key3, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
addr1 = crypto.PubkeyToAddress(key1.PublicKey)
addr2 = crypto.PubkeyToAddress(key2.PublicKey)
addr3 = crypto.PubkeyToAddress(key3.PublicKey)
db = ethdb.NewMemDatabase()
)
// Ensure that key1 has some funds in the genesis block.
gspec := &Genesis{
Config: ¶ms.ChainConfig{HomesteadBlock: new(big.Int)},
Alloc: GenesisAlloc{addr1: {Balance: big.NewInt(1000000)}},
}
genesis := gspec.MustCommit(db)
// This call generates a chain of 5 blocks. The function runs for
// each block and adds different features to gen based on the
// block index.
signer := types.HomesteadSigner{}
chain, _ := GenerateChain(gspec.Config, genesis, ethash.NewFaker(), db, 5, func(i int, gen *BlockGen) {
switch i {
case 0:
// In block 1, addr1 sends addr2 some ether.
tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), params.TxGas, nil, nil), signer, key1)
gen.AddTx(tx)
case 1:
// In block 2, addr1 sends some more ether to addr2.
// addr2 passes it on to addr3.
tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), params.TxGas, nil, nil), signer, key1)
tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), params.TxGas, nil, nil), signer, key2)
gen.AddTx(tx1)
gen.AddTx(tx2)
case 2:
// Block 3 is empty but was mined by addr3.
gen.SetCoinbase(addr3)
gen.SetExtra([]byte("yeehaw"))
case 3:
// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
b2 := gen.PrevBlock(1).Header()
b2.Extra = []byte("foo")
gen.AddUncle(b2)
b3 := gen.PrevBlock(2).Header()
b3.Extra = []byte("foo")
gen.AddUncle(b3)
}
})
// Import the chain. This runs all block validation rules.
blockchain, _ := NewBlockChain(db, nil, gspec.Config, ethash.NewFaker(), vm.Config{})
defer blockchain.Stop()
if i, err := blockchain.InsertChain(chain); err != nil {
fmt.Printf("insert error (block %d): %v\n", chain[i].NumberU64(), err)
return
}
state, _ := blockchain.State()
fmt.Printf("last block: #%d\n", blockchain.CurrentBlock().Number())
fmt.Println("balance of addr1:", state.GetBalance(addr1))
fmt.Println("balance of addr2:", state.GetBalance(addr2))
fmt.Println("balance of addr3:", state.GetBalance(addr3))
// Output:
// last block: #5
// balance of addr1: 989000
// balance of addr2: 10000
// balance of addr3: 19687500000000001000
}
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