github.com/cuiweixie/go-ethereum@v1.8.2-0.20180303084001-66cd41af1e38/consensus/consensus.go (about)

     1  // Copyright 2017 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 consensus implements different Ethereum consensus engines.
    18  package consensus
    19  
    20  import (
    21  	"github.com/ethereum/go-ethereum/common"
    22  	"github.com/ethereum/go-ethereum/core/state"
    23  	"github.com/ethereum/go-ethereum/core/types"
    24  	"github.com/ethereum/go-ethereum/params"
    25  	"github.com/ethereum/go-ethereum/rpc"
    26  	"math/big"
    27  )
    28  
    29  // ChainReader defines a small collection of methods needed to access the local
    30  // blockchain during header and/or uncle verification.
    31  type ChainReader interface {
    32  	// Config retrieves the blockchain's chain configuration.
    33  	Config() *params.ChainConfig
    34  
    35  	// CurrentHeader retrieves the current header from the local chain.
    36  	CurrentHeader() *types.Header
    37  
    38  	// GetHeader retrieves a block header from the database by hash and number.
    39  	GetHeader(hash common.Hash, number uint64) *types.Header
    40  
    41  	// GetHeaderByNumber retrieves a block header from the database by number.
    42  	GetHeaderByNumber(number uint64) *types.Header
    43  
    44  	// GetHeaderByHash retrieves a block header from the database by its hash.
    45  	GetHeaderByHash(hash common.Hash) *types.Header
    46  
    47  	// GetBlock retrieves a block from the database by hash and number.
    48  	GetBlock(hash common.Hash, number uint64) *types.Block
    49  }
    50  
    51  // Engine is an algorithm agnostic consensus engine.
    52  type Engine interface {
    53  	// Author retrieves the Ethereum address of the account that minted the given
    54  	// block, which may be different from the header's coinbase if a consensus
    55  	// engine is based on signatures.
    56  	Author(header *types.Header) (common.Address, error)
    57  
    58  	// VerifyHeader checks whether a header conforms to the consensus rules of a
    59  	// given engine. Verifying the seal may be done optionally here, or explicitly
    60  	// via the VerifySeal method.
    61  	VerifyHeader(chain ChainReader, header *types.Header, seal bool) error
    62  
    63  	// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
    64  	// concurrently. The method returns a quit channel to abort the operations and
    65  	// a results channel to retrieve the async verifications (the order is that of
    66  	// the input slice).
    67  	VerifyHeaders(chain ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error)
    68  
    69  	// VerifyUncles verifies that the given block's uncles conform to the consensus
    70  	// rules of a given engine.
    71  	VerifyUncles(chain ChainReader, block *types.Block) error
    72  
    73  	// VerifySeal checks whether the crypto seal on a header is valid according to
    74  	// the consensus rules of the given engine.
    75  	VerifySeal(chain ChainReader, header *types.Header) error
    76  
    77  	// Prepare initializes the consensus fields of a block header according to the
    78  	// rules of a particular engine. The changes are executed inline.
    79  	Prepare(chain ChainReader, header *types.Header) error
    80  
    81  	// Finalize runs any post-transaction state modifications (e.g. block rewards)
    82  	// and assembles the final block.
    83  	// Note: The block header and state database might be updated to reflect any
    84  	// consensus rules that happen at finalization (e.g. block rewards).
    85  	Finalize(chain ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction,
    86  		uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error)
    87  
    88  	// Seal generates a new block for the given input block with the local miner's
    89  	// seal place on top.
    90  	Seal(chain ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error)
    91  
    92  	// CalcDifficulty is the difficulty adjustment algorithm. It returns the difficulty
    93  	// that a new block should have.
    94  	CalcDifficulty(chain ChainReader, time uint64, parent *types.Header) *big.Int
    95  
    96  	// APIs returns the RPC APIs this consensus engine provides.
    97  	APIs(chain ChainReader) []rpc.API
    98  }
    99  
   100  // PoW is a consensus engine based on proof-of-work.
   101  type PoW interface {
   102  	Engine
   103  
   104  	// Hashrate returns the current mining hashrate of a PoW consensus engine.
   105  	Hashrate() float64
   106  }