159 lines
3.5 KiB
Go
159 lines
3.5 KiB
Go
package torrent
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import (
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"sync"
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"github.com/anacrolix/missinggo/bitmap"
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"github.com/anacrolix/torrent/metainfo"
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pp "github.com/anacrolix/torrent/peer_protocol"
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"github.com/anacrolix/torrent/storage"
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)
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// Piece priority describes the importance of obtaining a particular piece.
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type piecePriority byte
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func (pp *piecePriority) Raise(maybe piecePriority) {
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if maybe > *pp {
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*pp = maybe
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}
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}
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const (
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PiecePriorityNone piecePriority = iota // Not wanted.
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PiecePriorityNormal // Wanted.
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PiecePriorityReadahead // May be required soon.
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PiecePriorityNext // Succeeds a piece where a read occurred.
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PiecePriorityNow // A Reader is reading in this piece.
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)
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type piece struct {
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// The completed piece SHA1 hash, from the metainfo "pieces" field.
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Hash metainfo.Hash
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t *Torrent
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index int
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// Chunks we've written to since the last check. The chunk offset and
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// length can be determined by the request chunkSize in use.
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DirtyChunks bitmap.Bitmap
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Hashing bool
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QueuedForHash bool
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EverHashed bool
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PublicPieceState PieceState
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priority piecePriority
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pendingWritesMutex sync.Mutex
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pendingWrites int
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noPendingWrites sync.Cond
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}
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func (p *piece) Info() metainfo.Piece {
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return p.t.info.Piece(p.index)
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}
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func (p *piece) Storage() storage.Piece {
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return p.t.storage.Piece(p.Info())
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}
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func (p *piece) pendingChunkIndex(chunkIndex int) bool {
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return !p.DirtyChunks.Contains(chunkIndex)
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}
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func (p *piece) pendingChunk(cs chunkSpec, chunkSize pp.Integer) bool {
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return p.pendingChunkIndex(chunkIndex(cs, chunkSize))
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}
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func (p *piece) hasDirtyChunks() bool {
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return p.DirtyChunks.Len() != 0
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}
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func (p *piece) numDirtyChunks() (ret int) {
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return p.DirtyChunks.Len()
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}
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func (p *piece) unpendChunkIndex(i int) {
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p.DirtyChunks.Add(i)
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}
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func (p *piece) pendChunkIndex(i int) {
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p.DirtyChunks.Remove(i)
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}
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func (p *piece) numChunks() int {
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return p.t.pieceNumChunks(p.index)
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}
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func (p *piece) undirtiedChunkIndices() (ret bitmap.Bitmap) {
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ret = p.DirtyChunks.Copy()
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ret.FlipRange(0, p.numChunks())
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return
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}
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func (p *piece) incrementPendingWrites() {
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p.pendingWritesMutex.Lock()
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p.pendingWrites++
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p.pendingWritesMutex.Unlock()
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}
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func (p *piece) decrementPendingWrites() {
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p.pendingWritesMutex.Lock()
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if p.pendingWrites == 0 {
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panic("assertion")
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}
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p.pendingWrites--
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if p.pendingWrites == 0 {
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p.noPendingWrites.Broadcast()
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}
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p.pendingWritesMutex.Unlock()
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}
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func (p *piece) waitNoPendingWrites() {
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p.pendingWritesMutex.Lock()
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for p.pendingWrites != 0 {
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p.noPendingWrites.Wait()
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}
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p.pendingWritesMutex.Unlock()
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}
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func (p *piece) chunkIndexDirty(chunk int) bool {
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return p.DirtyChunks.Contains(chunk)
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}
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func (p *piece) chunkIndexSpec(chunk int) chunkSpec {
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return chunkIndexSpec(chunk, p.length(), p.chunkSize())
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}
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func (p *piece) numDirtyBytes() (ret pp.Integer) {
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defer func() {
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if ret > p.length() {
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panic("too many dirty bytes")
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}
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}()
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numRegularDirtyChunks := p.numDirtyChunks()
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if p.chunkIndexDirty(p.numChunks() - 1) {
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numRegularDirtyChunks--
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ret += p.chunkIndexSpec(p.lastChunkIndex()).Length
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}
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ret += pp.Integer(numRegularDirtyChunks) * p.chunkSize()
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return
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}
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func (p *piece) length() pp.Integer {
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return p.t.pieceLength(p.index)
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}
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func (p *piece) chunkSize() pp.Integer {
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return p.t.chunkSize
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}
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func (p *piece) lastChunkIndex() int {
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return p.numChunks() - 1
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}
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func (p *piece) bytesLeft() (ret pp.Integer) {
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if p.t.pieceComplete(p.index) {
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return 0
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}
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return p.length() - p.numDirtyBytes()
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}
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