/
reader.go
194 lines (177 loc) · 4.43 KB
/
reader.go
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package services
import (
"context"
"io"
"github.com/anacrolix/torrent/metainfo"
log "github.com/sirupsen/logrus"
"github.com/pkg/errors"
)
const (
MAX_PRELOAD_BYTES = 30_000_000
)
type Reader struct {
pp *PreloadPiecePool
ttp *TorrentTouchPool
mip *MetaInfoPool
src string
query string
hash string
path string
redirectURL string
touch bool
readOffset int64
offset int64
length int64
info *metainfo.Info
pn int64
cr io.ReadCloser
ctx context.Context
N int64
lb *LeakyBuffer
pqp *PreloadQueuePool
pid string
}
func NewReader(ctx context.Context, mip *MetaInfoPool, pp *PreloadPiecePool, ttp *TorrentTouchPool, lb *LeakyBuffer, pqp *PreloadQueuePool, src string, hash string, query string, offset int64, length int64, pid string) *Reader {
return &Reader{lb: lb, ttp: ttp, pp: pp, mip: mip, pqp: pqp, src: src, query: query,
hash: hash, readOffset: 0, touch: false, ctx: ctx, N: -1, offset: offset,
length: length, pid: pid}
}
func (r *Reader) Ready() (bool, error) {
mi, err := r.mip.Get(r.hash)
if err != nil {
return false, errors.Wrap(err, "Failed to get ready state")
}
return mi != nil, nil
}
func (r *Reader) getInfo() (*metainfo.Info, error) {
return r.mip.Get(r.hash)
}
func (r *Reader) getReader(limit int64) (io.Reader, error) {
if !r.touch {
r.touch = true
defer func() {
go func() {
if err := r.ttp.Touch(r.hash); err != nil {
log.WithError(err).Error("Failed to touch torrent")
}
}()
}()
}
if r.length < r.readOffset {
return nil, io.EOF
}
i, err := r.getInfo()
if err != nil {
return nil, errors.Wrap(err, "Failed to get Info")
}
offset := r.readOffset + r.offset
pieceNum := offset / i.PieceLength
piece := i.Piece(int(pieceNum))
pieceLength := piece.Length()
start := piece.Offset()
pieceStart := offset - start
pieceEnd := piece.Length() - 1
if start+piece.Length() > r.offset+r.readOffset+limit {
pieceEnd = r.offset + r.readOffset + limit - start - 1
}
full := pieceEnd-pieceStart == pieceLength-1
// Preload
preloadBytes := int64(float64(r.length) * 0.05)
if preloadBytes > MAX_PRELOAD_BYTES {
preloadBytes = MAX_PRELOAD_BYTES
}
preloadSize := preloadBytes / pieceLength
if r.pn != pieceNum {
for ii := pieceNum + 1; ii < pieceNum+preloadSize+1 && ii < int64(i.NumPieces()); ii++ {
r.pqp.Push(r.pid, r.src, r.hash, i.Piece(int(ii)).Hash().HexString(), r.query)
}
}
var pr io.ReadCloser
if r.cr == nil {
pr, err = r.pp.Get(r.ctx, r.src, r.hash, piece.Hash().HexString(), r.query, pieceStart, pieceEnd, full)
} else if r.cr != nil && pieceNum != r.pn {
r.cr.Close()
pr, err = r.pp.Get(r.ctx, r.src, r.hash, piece.Hash().HexString(), r.query, pieceStart, pieceEnd, full)
} else {
pr = r.cr
}
r.pqp.Push(r.pid, r.src, r.hash, i.Piece(int(pieceNum)).Hash().HexString(), r.query)
if err != nil {
return nil, errors.Wrap(err, "Failed to get Piece data")
}
r.cr = pr
r.pn = pieceNum
return r.cr, nil
}
func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
n = 0
var pr io.Reader
var nn int64
limit := r.length - r.readOffset
if r.N != -1 {
limit = r.N
}
for {
if r.ctx.Err() != nil {
log.WithError(r.ctx.Err()).Error("Got context error")
return n, r.ctx.Err()
}
pr, err = r.getReader(limit)
if err != nil {
return
}
buf := r.lb.Get()
nn, err = io.CopyBuffer(w, pr, buf)
r.lb.Put(buf)
n = n + nn
r.readOffset = r.readOffset + nn
limit = limit - nn
if err != nil {
log.WithError(err).Error("Failed to read Piece data")
return
} else if limit <= 0 || nn == 0 {
if r.cr != nil {
r.cr.Close()
}
return n, io.EOF
}
}
}
func (r *Reader) Read(p []byte) (n int, err error) {
rr, err := r.getReader(r.length - r.readOffset)
if err != nil {
return
}
n, err = rr.Read(p)
if err != nil {
log.WithError(err).Errorf("Failed to read")
}
r.readOffset = r.readOffset + int64(n)
return
}
func (r *Reader) Close() error {
if r.cr != nil {
r.cr.Close()
}
return nil
}
func (r *Reader) Seek(offset int64, whence int) (int64, error) {
newOffset := int64(0)
switch whence {
case io.SeekStart:
newOffset = offset
break
case io.SeekCurrent:
newOffset = r.readOffset + offset
break
case io.SeekEnd:
newOffset = r.length + offset
break
}
if newOffset < r.readOffset && r.cr != nil {
r.cr.Close()
r.cr = nil
}
r.readOffset = newOffset
return newOffset, nil
}