piece.go

   1 package torrent
   2
   3 import (
   4         "fmt"
   5         "sync"
   6
   7         "github.com/anacrolix/missinggo/bitmap"
   8
   9         "github.com/anacrolix/torrent/metainfo"
  10         pp "github.com/anacrolix/torrent/peer_protocol"
  11         "github.com/anacrolix/torrent/storage"
  12 )
  13
  14 // Describes the importance of obtaining a particular piece.
  15 type piecePriority byte
  16
  17 func (pp *piecePriority) Raise(maybe piecePriority) {
  18         if maybe > *pp {
  19                 *pp = maybe
  20         }
  21 }
  22
  23 // Priority for use in PriorityBitmap
  24 func (me piecePriority) BitmapPriority() int {
  25         return -int(me)
  26 }
  27
  28 const (
  29         PiecePriorityNone      piecePriority = iota // Not wanted. Must be the zero value.
  30         PiecePriorityNormal                         // Wanted.
  31         PiecePriorityHigh                           // Wanted a lot.
  32         PiecePriorityReadahead                      // May be required soon.
  33         // Succeeds a piece where a read occurred. Currently the same as Now,
  34         // apparently due to issues with caching.
  35         PiecePriorityNext
  36         PiecePriorityNow // A Reader is reading in this piece. Highest urgency.
  37 )
  38
  39 type Piece struct {
  40         // The completed piece SHA1 hash, from the metainfo "pieces" field.
  41         hash  metainfo.Hash
  42         t     *Torrent
  43         index int
  44         files []*File
  45         // Chunks we've written to since the last check. The chunk offset and
  46         // length can be determined by the request chunkSize in use.
  47         dirtyChunks bitmap.Bitmap
  48
  49         hashing             bool
  50         everHashed          bool
  51         numVerifies         int64
  52         storageCompletionOk bool
  53
  54         publicPieceState PieceState
  55         priority         piecePriority
  56
  57         pendingWritesMutex sync.Mutex
  58         pendingWrites      int
  59         noPendingWrites    sync.Cond
  60 }
  61
  62 func (p *Piece) String() string {
  63         return fmt.Sprintf("%s/%d", p.t.infoHash.HexString(), p.index)
  64 }
  65
  66 func (p *Piece) Info() metainfo.Piece {
  67         return p.t.info.Piece(p.index)
  68 }
  69
  70 func (p *Piece) Storage() storage.Piece {
  71         return p.t.storage.Piece(p.Info())
  72 }
  73
  74 func (p *Piece) pendingChunkIndex(chunkIndex int) bool {
  75         return !p.dirtyChunks.Contains(chunkIndex)
  76 }
  77
  78 func (p *Piece) pendingChunk(cs chunkSpec, chunkSize pp.Integer) bool {
  79         return p.pendingChunkIndex(chunkIndex(cs, chunkSize))
  80 }
  81
  82 func (p *Piece) hasDirtyChunks() bool {
  83         return p.dirtyChunks.Len() != 0
  84 }
  85
  86 func (p *Piece) numDirtyChunks() (ret int) {
  87         return p.dirtyChunks.Len()
  88 }
  89
  90 func (p *Piece) unpendChunkIndex(i int) {
  91         p.dirtyChunks.Add(i)
  92 }
  93
  94 func (p *Piece) pendChunkIndex(i int) {
  95         p.dirtyChunks.Remove(i)
  96 }
  97
  98 func (p *Piece) numChunks() int {
  99         return p.t.pieceNumChunks(p.index)
 100 }
 101
 102 func (p *Piece) undirtiedChunkIndices() (ret bitmap.Bitmap) {
 103         ret = p.dirtyChunks.Copy()
 104         ret.FlipRange(0, p.numChunks())
 105         return
 106 }
 107
 108 func (p *Piece) incrementPendingWrites() {
 109         p.pendingWritesMutex.Lock()
 110         p.pendingWrites++
 111         p.pendingWritesMutex.Unlock()
 112 }
 113
 114 func (p *Piece) decrementPendingWrites() {
 115         p.pendingWritesMutex.Lock()
 116         if p.pendingWrites == 0 {
 117                 panic("assertion")
 118         }
 119         p.pendingWrites--
 120         if p.pendingWrites == 0 {
 121                 p.noPendingWrites.Broadcast()
 122         }
 123         p.pendingWritesMutex.Unlock()
 124 }
 125
 126 func (p *Piece) waitNoPendingWrites() {
 127         p.pendingWritesMutex.Lock()
 128         for p.pendingWrites != 0 {
 129                 p.noPendingWrites.Wait()
 130         }
 131         p.pendingWritesMutex.Unlock()
 132 }
 133
 134 func (p *Piece) chunkIndexDirty(chunk int) bool {
 135         return p.dirtyChunks.Contains(chunk)
 136 }
 137
 138 func (p *Piece) chunkIndexSpec(chunk int) chunkSpec {
 139         return chunkIndexSpec(chunk, p.length(), p.chunkSize())
 140 }
 141
 142 func (p *Piece) numDirtyBytes() (ret pp.Integer) {
 143         // defer func() {
 144         //      if ret > p.length() {
 145         //              panic("too many dirty bytes")
 146         //      }
 147         // }()
 148         numRegularDirtyChunks := p.numDirtyChunks()
 149         if p.chunkIndexDirty(p.numChunks() - 1) {
 150                 numRegularDirtyChunks--
 151                 ret += p.chunkIndexSpec(p.lastChunkIndex()).Length
 152         }
 153         ret += pp.Integer(numRegularDirtyChunks) * p.chunkSize()
 154         return
 155 }
 156
 157 func (p *Piece) length() pp.Integer {
 158         return p.t.pieceLength(p.index)
 159 }
 160
 161 func (p *Piece) chunkSize() pp.Integer {
 162         return p.t.chunkSize
 163 }
 164
 165 func (p *Piece) lastChunkIndex() int {
 166         return p.numChunks() - 1
 167 }
 168
 169 func (p *Piece) bytesLeft() (ret pp.Integer) {
 170         if p.t.pieceComplete(p.index) {
 171                 return 0
 172         }
 173         return p.length() - p.numDirtyBytes()
 174 }
 175
 176 func (p *Piece) VerifyData() {
 177         p.t.cl.mu.Lock()
 178         defer p.t.cl.mu.Unlock()
 179         target := p.numVerifies + 1
 180         if p.hashing {
 181                 target++
 182         }
 183         // log.Printf("target: %d", target)
 184         p.t.queuePieceCheck(p.index)
 185         for p.numVerifies < target {
 186                 // log.Printf("got %d verifies", p.numVerifies)
 187                 p.t.cl.event.Wait()
 188         }
 189         // log.Print("done")
 190 }
 191
 192 func (p *Piece) queuedForHash() bool {
 193         return p.t.piecesQueuedForHash.Get(p.index)
 194 }
 195
 196 func (p *Piece) torrentBeginOffset() int64 {
 197         return int64(p.index) * p.t.info.PieceLength
 198 }
 199
 200 func (p *Piece) torrentEndOffset() int64 {
 201         return p.torrentBeginOffset() + int64(p.length())
 202 }