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// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package downloader
import (
"sync"
"golang.org/x/net/context"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/rpc"
)
// PublicDownloaderAPI provides an API which gives information about the current synchronisation status.
// It offers only methods that operates on data that can be available to anyone without security risks.
type PublicDownloaderAPI struct {
d *Downloader
mux *event.TypeMux
muSyncSubscriptions sync.Mutex
syncSubscriptions map[string]rpc.Subscription
}
// NewPublicDownloaderAPI create a new PublicDownloaderAPI.
func NewPublicDownloaderAPI(d *Downloader, m *event.TypeMux) *PublicDownloaderAPI {
api := &PublicDownloaderAPI{d: d, mux: m, syncSubscriptions: make(map[string]rpc.Subscription)}
go api.run()
return api
}
func (api *PublicDownloaderAPI) run() {
sub := api.mux.Subscribe(StartEvent{}, DoneEvent{}, FailedEvent{})
for event := range sub.Chan() {
var notification interface{}
switch event.Data.(type) {
case StartEvent:
result := &SyncingResult{Syncing: true}
result.Status.Origin, result.Status.Current, result.Status.Height, result.Status.Pulled, result.Status.Known = api.d.Progress()
notification = result
case DoneEvent, FailedEvent:
notification = false
}
api.muSyncSubscriptions.Lock()
for id, sub := range api.syncSubscriptions {
if sub.Notify(notification) == rpc.ErrNotificationNotFound {
delete(api.syncSubscriptions, id)
}
}
api.muSyncSubscriptions.Unlock()
}
}
// Progress gives progress indications when the node is synchronising with the Ethereum network.
type Progress struct {
Origin uint64 `json:"startingBlock"`
Current uint64 `json:"currentBlock"`
Height uint64 `json:"highestBlock"`
Pulled uint64 `json:"pulledStates"`
Known uint64 `json:"knownStates"`
}
// SyncingResult provides information about the current synchronisation status for this node.
type SyncingResult struct {
Syncing bool `json:"syncing"`
Status Progress `json:"status"`
}
// Syncing provides information when this nodes starts synchronising with the Ethereum network and when it's finished.
func (api *PublicDownloaderAPI) Syncing(ctx context.Context) (rpc.Subscription, error) {
notifier, supported := rpc.NotifierFromContext(ctx)
if !supported {
return nil, rpc.ErrNotificationsUnsupported
}
subscription, err := notifier.NewSubscription(func(id string) {
api.muSyncSubscriptions.Lock()
delete(api.syncSubscriptions, id)
api.muSyncSubscriptions.Unlock()
})
if err != nil {
return nil, err
}
api.muSyncSubscriptions.Lock()
api.syncSubscriptions[subscription.ID()] = subscription
api.muSyncSubscriptions.Unlock()
return subscription, nil
}
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