FedP2P/request_strategy.go

126 lines
3.4 KiB
Go

package torrent
import (
"sync"
"time"
"github.com/anacrolix/missinggo/v2/bitmap"
"github.com/anacrolix/missinggo/v2/prioritybitmap"
pp "github.com/anacrolix/torrent/peer_protocol"
)
type requestStrategyPiece interface {
numChunks() pp.Integer
dirtyChunks() bitmap.Bitmap
chunkIndexRequest(i pp.Integer) request
}
type requestStrategyTorrent interface {
numConns() int
numReaders() int
numPieces() int
readerPiecePriorities() (now, readahead bitmap.Bitmap)
ignorePieces() bitmap.Bitmap
pendingPieces() *prioritybitmap.PriorityBitmap
}
type requestStrategyConnection interface {
torrent() requestStrategyTorrent
peerPieces() bitmap.Bitmap
pieceRequestOrder() *prioritybitmap.PriorityBitmap
fastest() bool
stats() *ConnStats
totalExpectingTime() time.Duration
peerMaxRequests() int
chunksReceivedWhileExpecting() int64
}
type requestStrategy interface {
iterPendingPieces(requestStrategyConnection, func(pieceIndex) bool) bool
iterUndirtiedChunks(requestStrategyPiece, func(chunkSpec) bool) bool
nominalMaxRequests(requestStrategyConnection) int
shouldRequestWithoutBias(requestStrategyConnection) bool
piecePriority(requestStrategyConnection, pieceIndex, piecePriority, int) int
hooks() requestStrategyHooks
}
type requestStrategyHooks struct {
sentRequest func(request)
deletedRequest func(request)
}
type requestStrategyCallbacks interface {
requestTimedOut(request)
}
// Favour higher priority pieces with some fuzzing to reduce overlaps and wastage across
// connections.
type requestStrategyOne struct{}
// The fastest connection downloads strictly in order of priority, while all others adhere to their
// piece inclinations.
type requestStrategyTwo struct{}
func (requestStrategyTwo) ShouldRequestWithoutBias(cn requestStrategyConnection) bool {
if cn.torrent().numReaders() == 0 {
return false
}
if cn.torrent().numConns() == 1 {
return true
}
if cn.fastest() {
return true
}
return false
}
// Requests are strictly by piece priority, and not duplicated until duplicateRequestTimeout is
// reached.
type requestStrategyThree struct {
// How long to avoid duplicating a pending request.
duplicateRequestTimeout time.Duration
callbacks requestStrategyCallbacks
// The last time we requested a chunk. Deleting the request from any connection will clear this
// value.
lastRequested map[request]*time.Timer
// The lock to take when running a request timeout handler.
timeoutLocker sync.Locker
}
type requestStrategyMaker func(callbacks requestStrategyCallbacks, clientLocker sync.Locker) requestStrategy
func requestStrategyThreeMaker(duplicateRequestTimeout time.Duration) requestStrategyMaker {
return func(callbacks requestStrategyCallbacks, clientLocker sync.Locker) requestStrategy {
return requestStrategyThree{
duplicateRequestTimeout: duplicateRequestTimeout,
callbacks: callbacks,
lastRequested: make(map[request]*time.Timer),
timeoutLocker: clientLocker,
}
}
}
func (rs requestStrategyThree) hooks() requestStrategyHooks {
return requestStrategyHooks{
deletedRequest: func(r request) {
if t, ok := rs.lastRequested[r]; ok {
t.Stop()
delete(rs.lastRequested, r)
}
},
sentRequest: rs.onSentRequest,
}
}
func (rs requestStrategyOne) hooks() requestStrategyHooks {
return requestStrategyHooks{}
}
func (rs requestStrategyTwo) hooks() requestStrategyHooks {
return requestStrategyHooks{}
}