Golang Database.Get方法代码示例

func NewStateObjectFromBytes(address common.Address, data []byte, db ethdb.Database) *StateObject {
	// TODO clean me up
	var extobject struct {
		Nonce    uint64
		Balance  *big.Int
		Root     common.Hash
		CodeHash []byte
	}
	err := rlp.Decode(bytes.NewReader(data), &extobject)
	if err != nil {
		fmt.Println(err)
		return nil
	}

	object := &StateObject{address: address, db: db}
	object.nonce = extobject.Nonce
	object.balance = extobject.Balance
	object.codeHash = extobject.CodeHash
	object.trie = trie.NewSecure(extobject.Root[:], db)
	object.storage = make(map[string]common.Hash)
	object.gasPool = new(big.Int)
	object.code, _ = db.Get(extobject.CodeHash)

	return object
}

// GetTransaction retrieves a specific transaction from the database, along with
// its added positional metadata.
func GetTransaction(db ethdb.Database, hash common.Hash) (*types.Transaction, common.Hash, uint64, uint64) {
	// Retrieve the transaction itself from the database
	data, _ := db.Get(hash.Bytes())
	if len(data) == 0 {
		return nil, common.Hash{}, 0, 0
	}
	var tx types.Transaction
	if err := rlp.DecodeBytes(data, &tx); err != nil {
		return nil, common.Hash{}, 0, 0
	}
	// Retrieve the blockchain positional metadata
	data, _ = db.Get(append(hash.Bytes(), txMetaSuffix...))
	if len(data) == 0 {
		return nil, common.Hash{}, 0, 0
	}
	var meta struct {
		BlockHash  common.Hash
		BlockIndex uint64
		Index      uint64
	}
	if err := rlp.DecodeBytes(data, &meta); err != nil {
		return nil, common.Hash{}, 0, 0
	}
	return &tx, meta.BlockHash, meta.BlockIndex, meta.Index
}

// GetCanonicalHash retrieves a hash assigned to a canonical block number.
func GetCanonicalHash(db ethdb.Database, number uint64) common.Hash {
	data, _ := db.Get(append(blockNumPrefix, big.NewInt(int64(number)).Bytes()...))
	if len(data) == 0 {
		return common.Hash{}
	}
	return common.BytesToHash(data)
}

func NewStateObjectFromBytes(address common.Address, data []byte, db ethdb.Database) *StateObject {
	var extobject struct {
		Nonce    uint64
		Balance  *big.Int
		Root     common.Hash
		CodeHash []byte
	}
	err := rlp.Decode(bytes.NewReader(data), &extobject)
	if err != nil {
		glog.Errorf("can't decode state object %x: %v", address, err)
		return nil
	}
	trie, err := trie.NewSecure(extobject.Root, db)
	if err != nil {
		// TODO: bubble this up or panic
		glog.Errorf("can't create account trie with root %x: %v", extobject.Root[:], err)
		return nil
	}

	object := &StateObject{address: address, db: db}
	object.nonce = extobject.Nonce
	object.balance = extobject.Balance
	object.codeHash = extobject.CodeHash
	object.trie = trie
	object.storage = make(map[string]common.Hash)
	object.code, _ = db.Get(extobject.CodeHash)
	return object
}

// GetHeadFastBlockHash retrieves the hash of the current canonical head block during
// fast synchronization. The difference between this and GetHeadBlockHash is that
// whereas the last block hash is only updated upon a full block import, the last
// fast hash is updated when importing pre-processed blocks.
func GetHeadFastBlockHash(db ethdb.Database) common.Hash {
	data, _ := db.Get(headFastKey)
	if len(data) == 0 {
		return common.Hash{}
	}
	return common.BytesToHash(data)
}

func saveBlockchainVersion(db ethdb.Database, bcVersion int) {
	d, _ := db.Get([]byte("BlockchainVersion"))
	blockchainVersion := common.NewValue(d).Uint()

	if blockchainVersion == 0 {
		db.Put([]byte("BlockchainVersion"), common.NewValue(bcVersion).Bytes())
	}
}

// storeProof stores the new trie nodes obtained from a merkle proof in the database
func storeProof(db ethdb.Database, proof []rlp.RawValue) {
	for _, buf := range proof {
		hash := crypto.Keccak256(buf)
		val, _ := db.Get(hash)
		if val == nil {
			db.Put(hash, buf)
		}
	}
}

// upgradeChainDatabase ensures that the chain database stores block split into
// separate header and body entries.
func upgradeChainDatabase(db ethdb.Database) error {
	// Short circuit if the head block is stored already as separate header and body
	data, err := db.Get([]byte("LastBlock"))
	if err != nil {
		return nil
	}
	head := common.BytesToHash(data)

	if block := core.GetBlockByHashOld(db, head); block == nil {
		return nil
	}
	// At least some of the database is still the old format, upgrade (skip the head block!)
	glog.V(logger.Info).Info("Old database detected, upgrading...")

	if db, ok := db.(*ethdb.LDBDatabase); ok {
		blockPrefix := []byte("block-hash-")
		for it := db.NewIterator(); it.Next(); {
			// Skip anything other than a combined block
			if !bytes.HasPrefix(it.Key(), blockPrefix) {
				continue
			}
			// Skip the head block (merge last to signal upgrade completion)
			if bytes.HasSuffix(it.Key(), head.Bytes()) {
				continue
			}
			// Load the block, split and serialize (order!)
			block := core.GetBlockByHashOld(db, common.BytesToHash(bytes.TrimPrefix(it.Key(), blockPrefix)))

			if err := core.WriteTd(db, block.Hash(), block.DeprecatedTd()); err != nil {
				return err
			}
			if err := core.WriteBody(db, block.Hash(), block.Body()); err != nil {
				return err
			}
			if err := core.WriteHeader(db, block.Header()); err != nil {
				return err
			}
			if err := db.Delete(it.Key()); err != nil {
				return err
			}
		}
		// Lastly, upgrade the head block, disabling the upgrade mechanism
		current := core.GetBlockByHashOld(db, head)

		if err := core.WriteTd(db, current.Hash(), current.DeprecatedTd()); err != nil {
			return err
		}
		if err := core.WriteBody(db, current.Hash(), current.Body()); err != nil {
			return err
		}
		if err := core.WriteHeader(db, current.Header()); err != nil {
			return err
		}
	}
	return nil
}

func GetTransaction(db ethdb.Database, txhash common.Hash) *types.Transaction {
	data, _ := db.Get(txhash[:])
	if len(data) != 0 {
		var tx types.Transaction
		if err := rlp.DecodeBytes(data, &tx); err != nil {
			return nil
		}
		return &tx
	}
	return nil
}

// GetTd retrieves a block's total difficulty corresponding to the hash, nil if
// none found.
func GetTd(db ethdb.Database, hash common.Hash) *big.Int {
	data, _ := db.Get(append(append(blockPrefix, hash.Bytes()...), tdSuffix...))
	if len(data) == 0 {
		return nil
	}
	td := new(big.Int)
	if err := rlp.Decode(bytes.NewReader(data), td); err != nil {
		glog.V(logger.Error).Infof("invalid block total difficulty RLP for hash %x: %v", hash, err)
		return nil
	}
	return td
}

// [deprecated by the header/block split, remove eventually]
// GetBlockByHashOld returns the old combined block corresponding to the hash
// or nil if not found. This method is only used by the upgrade mechanism to
// access the old combined block representation. It will be dropped after the
// network transitions to eth/63.
func GetBlockByHashOld(db ethdb.Database, hash common.Hash) *types.Block {
	data, _ := db.Get(append(blockHashPrefix, hash[:]...))
	if len(data) == 0 {
		return nil
	}
	var block types.StorageBlock
	if err := rlp.Decode(bytes.NewReader(data), &block); err != nil {
		glog.V(logger.Error).Infof("invalid block RLP for hash %x: %v", hash, err)
		return nil
	}
	return (*types.Block)(&block)
}

// GetReceipt returns a receipt by hash
func GetReceipt(db ethdb.Database, txHash common.Hash) *types.Receipt {
	data, _ := db.Get(append(receiptsPrefix, txHash[:]...))
	if len(data) == 0 {
		return nil
	}
	var receipt types.ReceiptForStorage
	err := rlp.DecodeBytes(data, &receipt)
	if err != nil {
		glog.V(logger.Core).Infoln("GetReceipt err:", err)
	}
	return (*types.Receipt)(&receipt)
}

// GetBlockReceipts returns the receipts generated by the transactions
// included in block's given hash.
func GetBlockReceipts(db ethdb.Database, hash common.Hash) types.Receipts {
	data, _ := db.Get(append(blockReceiptsPre, hash[:]...))
	if len(data) == 0 {
		return nil
	}

	var receipts types.Receipts
	err := rlp.DecodeBytes(data, &receipts)
	if err != nil {
		glog.V(logger.Core).Infoln("GetReceiptse err", err)
	}
	return receipts
}

// GetChainConfig will fetch the network settings based on the given hash.
func GetChainConfig(db ethdb.Database, hash common.Hash) (*ChainConfig, error) {
	jsonChainConfig, _ := db.Get(append(configPrefix, hash[:]...))
	if len(jsonChainConfig) == 0 {
		return nil, ChainConfigNotFoundErr
	}

	var config ChainConfig
	if err := json.Unmarshal(jsonChainConfig, &config); err != nil {
		return nil, err
	}

	return &config, nil
}

// GetBlockReceipts retrieves the receipts generated by the transactions included
// in a block given by its hash.
func GetBlockReceipts(db ethdb.Database, hash common.Hash) types.Receipts {
	data, _ := db.Get(append(blockReceiptsPrefix, hash[:]...))
	if len(data) == 0 {
		return nil
	}
	storageReceipts := []*types.ReceiptForStorage{}
	if err := rlp.DecodeBytes(data, &storageReceipts); err != nil {
		glog.V(logger.Error).Infof("invalid receipt array RLP for hash %x: %v", hash, err)
		return nil
	}
	receipts := make(types.Receipts, len(storageReceipts))
	for i, receipt := range storageReceipts {
		receipts[i] = (*types.Receipt)(receipt)
	}
	return receipts
}