118 lines
2.1 KiB
Go
118 lines
2.1 KiB
Go
package downloader
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import (
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"errors"
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"math/big"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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)
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const (
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workingState = 2
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idleState = 4
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)
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type hashFetcherFn func(common.Hash) error
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type blockFetcherFn func([]common.Hash) error
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// XXX make threadsafe!!!!
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type peers map[string]*peer
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func (p peers) get(state int) []*peer {
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var peers []*peer
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for _, peer := range p {
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peer.mu.RLock()
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if peer.state == state {
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peers = append(peers, peer)
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}
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peer.mu.RUnlock()
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}
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return peers
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}
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func (p peers) setState(id string, state int) {
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if peer, exist := p[id]; exist {
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peer.mu.Lock()
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defer peer.mu.Unlock()
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peer.state = state
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}
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}
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func (p peers) getPeer(id string) *peer {
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return p[id]
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}
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func (p peers) bestPeer() *peer {
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var peer *peer
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for _, cp := range p {
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if peer == nil || cp.td.Cmp(peer.td) > 0 {
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peer = cp
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}
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}
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return peer
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}
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// peer represents an active peer
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type peer struct {
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state int // Peer state (working, idle)
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rep int // TODO peer reputation
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mu sync.RWMutex
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id string
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td *big.Int
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recentHash common.Hash
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getHashes hashFetcherFn
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getBlocks blockFetcherFn
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}
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// create a new peer
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func newPeer(id string, td *big.Int, hash common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
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return &peer{id: id, td: td, recentHash: hash, getHashes: getHashes, getBlocks: getBlocks, state: idleState}
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}
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// fetch a chunk using the peer
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func (p *peer) fetch(chunk *chunk) error {
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p.mu.Lock()
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defer p.mu.Unlock()
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if p.state == workingState {
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return errors.New("peer already fetching chunk")
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}
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// set working state
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p.state = workingState
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// convert the set to a fetchable slice
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hashes, i := make([]common.Hash, chunk.hashes.Size()), 0
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chunk.hashes.Each(func(v interface{}) bool {
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hashes[i] = v.(common.Hash)
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i++
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return true
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})
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p.getBlocks(hashes)
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return nil
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}
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// promote increases the peer's reputation
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func (p *peer) promote() {
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p.mu.Lock()
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defer p.mu.Unlock()
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p.rep++
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}
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// demote decreases the peer's reputation or leaves it at 0
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func (p *peer) demote() {
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p.mu.Lock()
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defer p.mu.Unlock()
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if p.rep > 1 {
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p.rep -= 2
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} else {
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p.rep = 0
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}
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}
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