b4a2681120
This PR reimplements the light client server pool. It is also a first step to move certain logic into a new lespay package. This package will contain the implementation of the lespay token sale functions, the token buying and selling logic and other components related to peer selection/prioritization and service quality evaluation. Over the long term this package will be reusable for incentivizing future protocols. Since the LES peer logic is now based on enode.Iterator, it can now use DNS-based fallback discovery to find servers. This document describes the function of the new components: https://gist.github.com/zsfelfoldi/3c7ace895234b7b345ab4f71dab102d4
108 lines
3.1 KiB
Go
108 lines
3.1 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package client
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import (
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"sync"
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"github.com/ethereum/go-ethereum/p2p/enode"
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"github.com/ethereum/go-ethereum/p2p/nodestate"
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)
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// FillSet tries to read nodes from an input iterator and add them to a node set by
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// setting the specified node state flag(s) until the size of the set reaches the target.
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// Note that other mechanisms (like other FillSet instances reading from different inputs)
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// can also set the same flag(s) and FillSet will always care about the total number of
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// nodes having those flags.
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type FillSet struct {
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lock sync.Mutex
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cond *sync.Cond
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ns *nodestate.NodeStateMachine
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input enode.Iterator
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closed bool
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flags nodestate.Flags
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count, target int
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}
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// NewFillSet creates a new FillSet
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func NewFillSet(ns *nodestate.NodeStateMachine, input enode.Iterator, flags nodestate.Flags) *FillSet {
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fs := &FillSet{
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ns: ns,
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input: input,
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flags: flags,
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}
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fs.cond = sync.NewCond(&fs.lock)
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ns.SubscribeState(flags, func(n *enode.Node, oldState, newState nodestate.Flags) {
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fs.lock.Lock()
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if oldState.Equals(flags) {
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fs.count--
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}
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if newState.Equals(flags) {
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fs.count++
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}
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if fs.target > fs.count {
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fs.cond.Signal()
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}
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fs.lock.Unlock()
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})
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go fs.readLoop()
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return fs
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}
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// readLoop keeps reading nodes from the input and setting the specified flags for them
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// whenever the node set size is under the current target
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func (fs *FillSet) readLoop() {
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for {
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fs.lock.Lock()
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for fs.target <= fs.count && !fs.closed {
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fs.cond.Wait()
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}
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fs.lock.Unlock()
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if !fs.input.Next() {
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return
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}
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fs.ns.SetState(fs.input.Node(), fs.flags, nodestate.Flags{}, 0)
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}
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}
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// SetTarget sets the current target for node set size. If the previous target was not
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// reached and FillSet was still waiting for the next node from the input then the next
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// incoming node will be added to the set regardless of the target. This ensures that
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// all nodes coming from the input are eventually added to the set.
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func (fs *FillSet) SetTarget(target int) {
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fs.lock.Lock()
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defer fs.lock.Unlock()
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fs.target = target
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if fs.target > fs.count {
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fs.cond.Signal()
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}
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}
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// Close shuts FillSet down and closes the input iterator
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func (fs *FillSet) Close() {
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fs.lock.Lock()
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defer fs.lock.Unlock()
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fs.closed = true
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fs.input.Close()
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fs.cond.Signal()
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}
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