1// Copyright 2021 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
17package downloader
18
19import (
20	"time"
21
22	"github.com/ethereum/go-ethereum/common"
23	"github.com/ethereum/go-ethereum/eth/protocols/eth"
24	"github.com/ethereum/go-ethereum/log"
25)
26
27// receiptQueue implements typedQueue and is a type adapter between the generic
28// concurrent fetcher and the downloader.
29type receiptQueue Downloader
30
31// waker returns a notification channel that gets pinged in case more reecipt
32// fetches have been queued up, so the fetcher might assign it to idle peers.
33func (q *receiptQueue) waker() chan bool {
34	return q.queue.receiptWakeCh
35}
36
37// pending returns the number of receipt that are currently queued for fetching
38// by the concurrent downloader.
39func (q *receiptQueue) pending() int {
40	return q.queue.PendingReceipts()
41}
42
43// capacity is responsible for calculating how many receipts a particular peer is
44// estimated to be able to retrieve within the alloted round trip time.
45func (q *receiptQueue) capacity(peer *peerConnection, rtt time.Duration) int {
46	return peer.ReceiptCapacity(rtt)
47}
48
49// updateCapacity is responsible for updating how many receipts a particular peer
50// is estimated to be able to retrieve in a unit time.
51func (q *receiptQueue) updateCapacity(peer *peerConnection, items int, span time.Duration) {
52	peer.UpdateReceiptRate(items, span)
53}
54
55// reserve is responsible for allocating a requested number of pending receipts
56// from the download queue to the specified peer.
57func (q *receiptQueue) reserve(peer *peerConnection, items int) (*fetchRequest, bool, bool) {
58	return q.queue.ReserveReceipts(peer, items)
59}
60
61// unreserve is resposible for removing the current receipt retrieval allocation
62// assigned to a specific peer and placing it back into the pool to allow
63// reassigning to some other peer.
64func (q *receiptQueue) unreserve(peer string) int {
65	fails := q.queue.ExpireReceipts(peer)
66	if fails > 2 {
67		log.Trace("Receipt delivery timed out", "peer", peer)
68	} else {
69		log.Debug("Receipt delivery stalling", "peer", peer)
70	}
71	return fails
72}
73
74// request is responsible for converting a generic fetch request into a receipt
75// one and sending it to the remote peer for fulfillment.
76func (q *receiptQueue) request(peer *peerConnection, req *fetchRequest, resCh chan *eth.Response) (*eth.Request, error) {
77	peer.log.Trace("Requesting new batch of receipts", "count", len(req.Headers), "from", req.Headers[0].Number)
78	if q.receiptFetchHook != nil {
79		q.receiptFetchHook(req.Headers)
80	}
81	hashes := make([]common.Hash, 0, len(req.Headers))
82	for _, header := range req.Headers {
83		hashes = append(hashes, header.Hash())
84	}
85	return peer.peer.RequestReceipts(hashes, resCh)
86}
87
88// deliver is responsible for taking a generic response packet from the concurrent
89// fetcher, unpacking the receipt data and delivering it to the downloader's queue.
90func (q *receiptQueue) deliver(peer *peerConnection, packet *eth.Response) (int, error) {
91	receipts := *packet.Res.(*eth.ReceiptsPacket)
92	hashes := packet.Meta.([]common.Hash) // {receipt hashes}
93
94	accepted, err := q.queue.DeliverReceipts(peer.id, receipts, hashes)
95	switch {
96	case err == nil && len(receipts) == 0:
97		peer.log.Trace("Requested receipts delivered")
98	case err == nil:
99		peer.log.Trace("Delivered new batch of receipts", "count", len(receipts), "accepted", accepted)
100	default:
101		peer.log.Debug("Failed to deliver retrieved receipts", "err", err)
102	}
103	return accepted, err
104}
105