github.com/r8d8/go-ethereum@v5.5.2+incompatible/eth/downloader/api.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 downloader
    18  
    19  import (
    20  	"context"
    21  	"sync"
    22  
    23  	"math/big"
    24  
    25  	"github.com/ethereumproject/go-ethereum/common"
    26  	"github.com/ethereumproject/go-ethereum/event"
    27  	"github.com/ethereumproject/go-ethereum/rpc"
    28  )
    29  
    30  type DoneEvent struct {
    31  	Peer *peer
    32  	Hash common.Hash
    33  	TD   *big.Int
    34  }
    35  type StartEvent struct {
    36  	Peer *peer
    37  	Hash common.Hash
    38  	TD   *big.Int
    39  }
    40  type FailedEvent struct {
    41  	Peer *peer
    42  	Err  error
    43  }
    44  
    45  // PublicDownloaderAPI provides an API which gives information about the current synchronisation status.
    46  // It offers only methods that operates on data that can be available to anyone without security risks.
    47  type PublicDownloaderAPI struct {
    48  	d                   *Downloader
    49  	mux                 *event.TypeMux
    50  	muSyncSubscriptions sync.Mutex
    51  	syncSubscriptions   map[string]rpc.Subscription
    52  }
    53  
    54  // NewPublicDownloaderAPI create a new PublicDownloaderAPI.
    55  func NewPublicDownloaderAPI(d *Downloader, m *event.TypeMux) *PublicDownloaderAPI {
    56  	api := &PublicDownloaderAPI{d: d, mux: m, syncSubscriptions: make(map[string]rpc.Subscription)}
    57  
    58  	go api.run()
    59  
    60  	return api
    61  }
    62  
    63  func (api *PublicDownloaderAPI) run() {
    64  	sub := api.mux.Subscribe(StartEvent{}, DoneEvent{}, FailedEvent{})
    65  
    66  	for event := range sub.Chan() {
    67  		var notification interface{}
    68  
    69  		switch event.Data.(type) {
    70  		case StartEvent:
    71  			result := &SyncingResult{Syncing: true}
    72  			result.Status.Origin, result.Status.Current, result.Status.Height, result.Status.Pulled, result.Status.Known = api.d.Progress()
    73  			notification = result
    74  		case DoneEvent, FailedEvent:
    75  			notification = false
    76  		}
    77  
    78  		api.muSyncSubscriptions.Lock()
    79  		for id, sub := range api.syncSubscriptions {
    80  			if sub.Notify(notification) == rpc.ErrNotificationNotFound {
    81  				delete(api.syncSubscriptions, id)
    82  			}
    83  		}
    84  		api.muSyncSubscriptions.Unlock()
    85  	}
    86  }
    87  
    88  // Progress gives progress indications when the node is synchronising with the Ethereum network.
    89  type Progress struct {
    90  	Origin  uint64 `json:"startingBlock"`
    91  	Current uint64 `json:"currentBlock"`
    92  	Height  uint64 `json:"highestBlock"`
    93  	Pulled  uint64 `json:"pulledStates"`
    94  	Known   uint64 `json:"knownStates"`
    95  }
    96  
    97  // SyncingResult provides information about the current synchronisation status for this node.
    98  type SyncingResult struct {
    99  	Syncing bool     `json:"syncing"`
   100  	Status  Progress `json:"status"`
   101  }
   102  
   103  // Syncing provides information when this nodes starts synchronising with the Ethereum network and when it's finished.
   104  func (api *PublicDownloaderAPI) Syncing(ctx context.Context) (rpc.Subscription, error) {
   105  	notifier, supported := rpc.NotifierFromContext(ctx)
   106  	if !supported {
   107  		return nil, rpc.ErrNotificationsUnsupported
   108  	}
   109  
   110  	subscription, err := notifier.NewSubscription(func(id string) {
   111  		api.muSyncSubscriptions.Lock()
   112  		delete(api.syncSubscriptions, id)
   113  		api.muSyncSubscriptions.Unlock()
   114  	})
   115  
   116  	if err != nil {
   117  		return nil, err
   118  	}
   119  
   120  	api.muSyncSubscriptions.Lock()
   121  	api.syncSubscriptions[subscription.ID()] = subscription
   122  	api.muSyncSubscriptions.Unlock()
   123  
   124  	return subscription, nil
   125  }