github.com/fxsjy/go-ethereum@v1.8.4-0.20180410143526-2e247705cd27/les/odr.go (about)

     1  // Copyright 2016 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 les
    18  
    19  import (
    20  	"context"
    21  
    22  	"github.com/ethereum/go-ethereum/core"
    23  	"github.com/ethereum/go-ethereum/ethdb"
    24  	"github.com/ethereum/go-ethereum/light"
    25  	"github.com/ethereum/go-ethereum/log"
    26  )
    27  
    28  // LesOdr implements light.OdrBackend
    29  type LesOdr struct {
    30  	db                                         ethdb.Database
    31  	chtIndexer, bloomTrieIndexer, bloomIndexer *core.ChainIndexer
    32  	retriever                                  *retrieveManager
    33  	stop                                       chan struct{}
    34  }
    35  
    36  func NewLesOdr(db ethdb.Database, chtIndexer, bloomTrieIndexer, bloomIndexer *core.ChainIndexer, retriever *retrieveManager) *LesOdr {
    37  	return &LesOdr{
    38  		db:               db,
    39  		chtIndexer:       chtIndexer,
    40  		bloomTrieIndexer: bloomTrieIndexer,
    41  		bloomIndexer:     bloomIndexer,
    42  		retriever:        retriever,
    43  		stop:             make(chan struct{}),
    44  	}
    45  }
    46  
    47  // Stop cancels all pending retrievals
    48  func (odr *LesOdr) Stop() {
    49  	close(odr.stop)
    50  }
    51  
    52  // Database returns the backing database
    53  func (odr *LesOdr) Database() ethdb.Database {
    54  	return odr.db
    55  }
    56  
    57  // ChtIndexer returns the CHT chain indexer
    58  func (odr *LesOdr) ChtIndexer() *core.ChainIndexer {
    59  	return odr.chtIndexer
    60  }
    61  
    62  // BloomTrieIndexer returns the bloom trie chain indexer
    63  func (odr *LesOdr) BloomTrieIndexer() *core.ChainIndexer {
    64  	return odr.bloomTrieIndexer
    65  }
    66  
    67  // BloomIndexer returns the bloombits chain indexer
    68  func (odr *LesOdr) BloomIndexer() *core.ChainIndexer {
    69  	return odr.bloomIndexer
    70  }
    71  
    72  const (
    73  	MsgBlockBodies = iota
    74  	MsgCode
    75  	MsgReceipts
    76  	MsgProofsV1
    77  	MsgProofsV2
    78  	MsgHeaderProofs
    79  	MsgHelperTrieProofs
    80  )
    81  
    82  // Msg encodes a LES message that delivers reply data for a request
    83  type Msg struct {
    84  	MsgType int
    85  	ReqID   uint64
    86  	Obj     interface{}
    87  }
    88  
    89  // Retrieve tries to fetch an object from the LES network.
    90  // If the network retrieval was successful, it stores the object in local db.
    91  func (odr *LesOdr) Retrieve(ctx context.Context, req light.OdrRequest) (err error) {
    92  	lreq := LesRequest(req)
    93  
    94  	reqID := genReqID()
    95  	rq := &distReq{
    96  		getCost: func(dp distPeer) uint64 {
    97  			return lreq.GetCost(dp.(*peer))
    98  		},
    99  		canSend: func(dp distPeer) bool {
   100  			p := dp.(*peer)
   101  			return lreq.CanSend(p)
   102  		},
   103  		request: func(dp distPeer) func() {
   104  			p := dp.(*peer)
   105  			cost := lreq.GetCost(p)
   106  			p.fcServer.QueueRequest(reqID, cost)
   107  			return func() { lreq.Request(reqID, p) }
   108  		},
   109  	}
   110  
   111  	if err = odr.retriever.retrieve(ctx, reqID, rq, func(p distPeer, msg *Msg) error { return lreq.Validate(odr.db, msg) }, odr.stop); err == nil {
   112  		// retrieved from network, store in db
   113  		req.StoreResult(odr.db)
   114  	} else {
   115  		log.Debug("Failed to retrieve data from network", "err", err)
   116  	}
   117  	return
   118  }