256 lines
7.4 KiB
Go
256 lines
7.4 KiB
Go
package torrent
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import (
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"container/heap"
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"context"
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"encoding/gob"
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"reflect"
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"runtime/pprof"
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"time"
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"unsafe"
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"github.com/anacrolix/log"
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"github.com/anacrolix/multiless"
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request_strategy "github.com/anacrolix/torrent/request-strategy"
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)
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func (t *Torrent) requestStrategyPieceOrderState(i int) request_strategy.PieceRequestOrderState {
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return request_strategy.PieceRequestOrderState{
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Priority: t.piece(i).purePriority(),
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Partial: t.piecePartiallyDownloaded(i),
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Availability: t.piece(i).availability,
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}
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}
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func init() {
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gob.Register(peerId{})
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}
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type peerId struct {
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*Peer
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ptr uintptr
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}
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func (p peerId) Uintptr() uintptr {
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return p.ptr
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}
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func (p peerId) GobEncode() (b []byte, _ error) {
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*(*reflect.SliceHeader)(unsafe.Pointer(&b)) = reflect.SliceHeader{
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Data: uintptr(unsafe.Pointer(&p.ptr)),
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Len: int(unsafe.Sizeof(p.ptr)),
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Cap: int(unsafe.Sizeof(p.ptr)),
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}
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return
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}
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func (p *peerId) GobDecode(b []byte) error {
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if uintptr(len(b)) != unsafe.Sizeof(p.ptr) {
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panic(len(b))
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}
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ptr := unsafe.Pointer(&b[0])
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p.ptr = *(*uintptr)(ptr)
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log.Printf("%p", ptr)
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dst := reflect.SliceHeader{
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Data: uintptr(unsafe.Pointer(&p.Peer)),
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Len: int(unsafe.Sizeof(p.Peer)),
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Cap: int(unsafe.Sizeof(p.Peer)),
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}
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copy(*(*[]byte)(unsafe.Pointer(&dst)), b)
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return nil
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}
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type (
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RequestIndex = request_strategy.RequestIndex
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chunkIndexType = request_strategy.ChunkIndex
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)
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type peerRequests struct {
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requestIndexes []RequestIndex
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peer *Peer
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}
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func (p *peerRequests) Len() int {
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return len(p.requestIndexes)
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}
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func (p *peerRequests) Less(i, j int) bool {
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leftRequest := p.requestIndexes[i]
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rightRequest := p.requestIndexes[j]
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t := p.peer.t
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leftPieceIndex := leftRequest / t.chunksPerRegularPiece()
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rightPieceIndex := rightRequest / t.chunksPerRegularPiece()
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ml := multiless.New()
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// Push requests that can't be served right now to the end. But we don't throw them away unless
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// there's a better alternative. This is for when we're using the fast extension and get choked
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// but our requests could still be good when we get unchoked.
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if p.peer.peerChoking {
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ml = ml.Bool(
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!p.peer.peerAllowedFast.Contains(leftPieceIndex),
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!p.peer.peerAllowedFast.Contains(rightPieceIndex),
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)
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}
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leftPeer := t.pendingRequests[leftRequest]
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rightPeer := t.pendingRequests[rightRequest]
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ml = ml.Bool(rightPeer == p.peer, leftPeer == p.peer)
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ml = ml.Bool(rightPeer == nil, leftPeer == nil)
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if ml.Ok() {
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return ml.MustLess()
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}
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if leftPeer != nil {
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// The right peer should also be set, or we'd have resolved the computation by now.
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ml = ml.Uint64(
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rightPeer.requestState.Requests.GetCardinality(),
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leftPeer.requestState.Requests.GetCardinality(),
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)
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// Could either of the lastRequested be Zero? That's what checking an existing peer is for.
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leftLast := t.lastRequested[leftRequest]
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rightLast := t.lastRequested[rightRequest]
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if leftLast.IsZero() || rightLast.IsZero() {
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panic("expected non-zero last requested times")
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}
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// We want the most-recently requested on the left. Clients like Transmission serve requests
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// in received order, so the most recently-requested is the one that has the longest until
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// it will be served and therefore is the best candidate to cancel.
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ml = ml.CmpInt64(rightLast.Sub(leftLast).Nanoseconds())
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}
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leftPiece := t.piece(int(leftPieceIndex))
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rightPiece := t.piece(int(rightPieceIndex))
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ml = ml.Int(
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// Technically we would be happy with the cached priority here, except we don't actually
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// cache it anymore, and Torrent.piecePriority just does another lookup of *Piece to resolve
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// the priority through Piece.purePriority, which is probably slower.
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-int(leftPiece.purePriority()),
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-int(rightPiece.purePriority()),
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)
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ml = ml.Int(
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int(leftPiece.availability),
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int(rightPiece.availability))
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return ml.Less()
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}
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func (p *peerRequests) Swap(i, j int) {
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p.requestIndexes[i], p.requestIndexes[j] = p.requestIndexes[j], p.requestIndexes[i]
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}
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func (p *peerRequests) Push(x interface{}) {
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p.requestIndexes = append(p.requestIndexes, x.(RequestIndex))
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}
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func (p *peerRequests) Pop() interface{} {
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last := len(p.requestIndexes) - 1
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x := p.requestIndexes[last]
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p.requestIndexes = p.requestIndexes[:last]
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return x
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}
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type desiredRequestState struct {
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Requests peerRequests
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Interested bool
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}
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func (p *Peer) getDesiredRequestState() (desired desiredRequestState) {
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if !p.t.haveInfo() {
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return
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}
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input := p.t.getRequestStrategyInput()
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requestHeap := peerRequests{
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peer: p,
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}
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request_strategy.GetRequestablePieces(
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input,
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p.t.getPieceRequestOrder(),
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func(ih InfoHash, pieceIndex int) {
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if ih != p.t.infoHash {
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return
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}
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if !p.peerHasPiece(pieceIndex) {
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return
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}
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allowedFast := p.peerAllowedFast.ContainsInt(pieceIndex)
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p.t.piece(pieceIndex).undirtiedChunksIter.Iter(func(ci request_strategy.ChunkIndex) {
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r := p.t.pieceRequestIndexOffset(pieceIndex) + ci
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if !allowedFast {
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// We must signal interest to request this. TODO: We could set interested if the
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// peers pieces (minus the allowed fast set) overlap with our missing pieces if
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// there are any readers, or any pending pieces.
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desired.Interested = true
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// We can make or will allow sustaining a request here if we're not choked, or
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// have made the request previously (presumably while unchoked), and haven't had
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// the peer respond yet (and the request was retained because we are using the
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// fast extension).
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if p.peerChoking && !p.requestState.Requests.Contains(r) {
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// We can't request this right now.
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return
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}
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}
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if p.requestState.Cancelled.Contains(r) {
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// Can't re-request while awaiting acknowledgement.
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return
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}
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requestHeap.requestIndexes = append(requestHeap.requestIndexes, r)
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})
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},
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)
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p.t.assertPendingRequests()
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desired.Requests = requestHeap
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return
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}
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func (p *Peer) maybeUpdateActualRequestState() bool {
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if p.needRequestUpdate == "" {
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return true
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}
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var more bool
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pprof.Do(
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context.Background(),
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pprof.Labels("update request", p.needRequestUpdate),
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func(_ context.Context) {
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next := p.getDesiredRequestState()
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more = p.applyRequestState(next)
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},
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)
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return more
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}
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// Transmit/action the request state to the peer.
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func (p *Peer) applyRequestState(next desiredRequestState) bool {
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current := &p.requestState
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if !p.setInterested(next.Interested) {
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return false
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}
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more := true
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requestHeap := &next.Requests
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t := p.t
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heap.Init(requestHeap)
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for requestHeap.Len() != 0 && maxRequests(current.Requests.GetCardinality()) < p.nominalMaxRequests() {
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req := heap.Pop(requestHeap).(RequestIndex)
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existing := t.requestingPeer(req)
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if existing != nil && existing != p {
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// Don't steal from the poor.
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diff := int64(current.Requests.GetCardinality()) + 1 - (int64(existing.uncancelledRequests()) - 1)
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// Steal a request that leaves us with one more request than the existing peer
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// connection if the stealer more recently received a chunk.
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if diff > 1 || (diff == 1 && p.lastUsefulChunkReceived.Before(existing.lastUsefulChunkReceived)) {
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continue
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}
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t.cancelRequest(req)
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}
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more = p.mustRequest(req)
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if !more {
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break
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}
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}
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// TODO: This may need to change, we might want to update even if there were no requests due to
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// filtering them for being recently requested already.
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p.updateRequestsTimer.Stop()
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if more {
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p.needRequestUpdate = ""
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if current.Interested {
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p.updateRequestsTimer.Reset(3 * time.Second)
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}
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}
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return more
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}
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