github.com/devfans/go-ethereum@v1.5.10-0.20170326212234-7419d0c38291/core/chain_makers_test.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import (
    20  	"fmt"
    21  	"math/big"
    22  
    23  	"github.com/ethereum/go-ethereum/core/types"
    24  	"github.com/ethereum/go-ethereum/core/vm"
    25  	"github.com/ethereum/go-ethereum/crypto"
    26  	"github.com/ethereum/go-ethereum/ethdb"
    27  	"github.com/ethereum/go-ethereum/event"
    28  	"github.com/ethereum/go-ethereum/params"
    29  	"github.com/ethereum/go-ethereum/pow"
    30  )
    31  
    32  func ExampleGenerateChain() {
    33  	var (
    34  		key1, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
    35  		key2, _ = crypto.HexToECDSA("8a1f9a8f95be41cd7ccb6168179afb4504aefe388d1e14474d32c45c72ce7b7a")
    36  		key3, _ = crypto.HexToECDSA("49a7b37aa6f6645917e7b807e9d1c00d4fa71f18343b0d4122a4d2df64dd6fee")
    37  		addr1   = crypto.PubkeyToAddress(key1.PublicKey)
    38  		addr2   = crypto.PubkeyToAddress(key2.PublicKey)
    39  		addr3   = crypto.PubkeyToAddress(key3.PublicKey)
    40  		db, _   = ethdb.NewMemDatabase()
    41  	)
    42  
    43  	// Ensure that key1 has some funds in the genesis block.
    44  	gspec := &Genesis{
    45  		Config: &params.ChainConfig{HomesteadBlock: new(big.Int)},
    46  		Alloc:  GenesisAlloc{addr1: {Balance: big.NewInt(1000000)}},
    47  	}
    48  	genesis := gspec.MustCommit(db)
    49  
    50  	// This call generates a chain of 5 blocks. The function runs for
    51  	// each block and adds different features to gen based on the
    52  	// block index.
    53  	signer := types.HomesteadSigner{}
    54  	chain, _ := GenerateChain(gspec.Config, genesis, db, 5, func(i int, gen *BlockGen) {
    55  		switch i {
    56  		case 0:
    57  			// In block 1, addr1 sends addr2 some ether.
    58  			tx, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(10000), bigTxGas, nil, nil), signer, key1)
    59  			gen.AddTx(tx)
    60  		case 1:
    61  			// In block 2, addr1 sends some more ether to addr2.
    62  			// addr2 passes it on to addr3.
    63  			tx1, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr1), addr2, big.NewInt(1000), bigTxGas, nil, nil), signer, key1)
    64  			tx2, _ := types.SignTx(types.NewTransaction(gen.TxNonce(addr2), addr3, big.NewInt(1000), bigTxGas, nil, nil), signer, key2)
    65  			gen.AddTx(tx1)
    66  			gen.AddTx(tx2)
    67  		case 2:
    68  			// Block 3 is empty but was mined by addr3.
    69  			gen.SetCoinbase(addr3)
    70  			gen.SetExtra([]byte("yeehaw"))
    71  		case 3:
    72  			// Block 4 includes blocks 2 and 3 as uncle headers (with modified extra data).
    73  			b2 := gen.PrevBlock(1).Header()
    74  			b2.Extra = []byte("foo")
    75  			gen.AddUncle(b2)
    76  			b3 := gen.PrevBlock(2).Header()
    77  			b3.Extra = []byte("foo")
    78  			gen.AddUncle(b3)
    79  		}
    80  	})
    81  
    82  	// Import the chain. This runs all block validation rules.
    83  	evmux := &event.TypeMux{}
    84  	blockchain, _ := NewBlockChain(db, gspec.Config, pow.FakePow{}, evmux, vm.Config{})
    85  	if i, err := blockchain.InsertChain(chain); err != nil {
    86  		fmt.Printf("insert error (block %d): %v\n", chain[i].NumberU64(), err)
    87  		return
    88  	}
    89  
    90  	state, _ := blockchain.State()
    91  	fmt.Printf("last block: #%d\n", blockchain.CurrentBlock().Number())
    92  	fmt.Println("balance of addr1:", state.GetBalance(addr1))
    93  	fmt.Println("balance of addr2:", state.GetBalance(addr2))
    94  	fmt.Println("balance of addr3:", state.GetBalance(addr3))
    95  	// Output:
    96  	// last block: #5
    97  	// balance of addr1: 989000
    98  	// balance of addr2: 10000
    99  	// balance of addr3: 19687500000000001000
   100  }