forked from cerc-io/plugeth
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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