public static BlockInfo?PickPiece(this IPiecePicker picker, IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers)
{
Span <BlockInfo> buffer = stackalloc BlockInfo[1];
var result = picker.PickPiece(peer, available, otherPeers, 0, available.Length - 1, buffer);
return(result == 1 ? (BlockInfo?)buffer[0] : null);
}
internal FastResume(BEncodedDictionary dict)
{
CheckVersion(dict);
CheckContent(dict, InfoHashKey);
CheckContent(dict, BitfieldKey);
CheckContent(dict, BitfieldLengthKey);
// BEP52: Support backwards/forwards compatibility
var infoHash = InfoHash.FromMemory(((BEncodedString)dict[InfoHashKey]).AsMemory());
if (infoHash.Span.Length == 20)
{
InfoHashes = InfoHashes.FromV1(infoHash);
}
else
{
InfoHashes = InfoHashes.FromV2(infoHash);
}
var data = ((BEncodedString)dict[BitfieldKey]).Span;
Bitfield = new ReadOnlyBitField(data, (int)((BEncodedNumber)dict[BitfieldLengthKey]).Number);
// If we're loading up an older version of the FastResume data then we
if (dict.ContainsKey(UnhashedPiecesKey))
{
data = ((BEncodedString)dict[UnhashedPiecesKey]).Span;
UnhashedPieces = new ReadOnlyBitField(data, Bitfield.Length);
}
else
{
UnhashedPieces = new ReadOnlyBitField(Bitfield.Length);
}
}
public override int PickPiece(IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers, int startIndex, int endIndex, Span <BlockInfo> requests)
{
if (available.AllFalse)
{
return(0);
}
if (requests.Length > 1)
{
return(base.PickPiece(peer, available, otherPeers, startIndex, endIndex, requests));
}
GenerateRarestFirst(available, otherPeers);
while (rarest.Count > 0)
{
BitField current = rarest.Pop();
int requested = base.PickPiece(peer, current, otherPeers, startIndex, endIndex, requests);
spares.Push(current);
if (requested > 0)
{
return(requested);
}
}
return(0);
}
public static BlockInfo?PickPiece(this IPiecePicker picker, IPeer peer, ReadOnlyBitField available)
{
Span <BlockInfo> buffer = stackalloc BlockInfo[1];
var picked = picker.PickPiece(peer, available, Array.Empty <IPeer> (), 0, available.Length - 1, buffer);
return(picked == 1 ? (BlockInfo?)buffer[0] : null);
}
public override bool IsInteresting(IPeer peer, ReadOnlyBitField bitfield)
{
if (temp is null || allPrioritisedPieces is null)
{
return(false);
}
if (ShouldRebuildSelectors())
{
BuildSelectors();
}
if (files.Count == 1 || files.TrueForAll(AllSamePriority))
{
if (files[0].Priority == Priority.DoNotDownload)
{
return(false);
}
return(base.IsInteresting(peer, bitfield));
}
else
{
temp.From(allPrioritisedPieces).And(bitfield);
if (temp.AllFalse)
{
return(false);
}
return(base.IsInteresting(peer, temp));
}
}
internal FastResume(InfoHashes infoHashes, ReadOnlyBitField bitfield, ReadOnlyBitField unhashedPieces)
{
InfoHashes = infoHashes ?? throw new ArgumentNullException(nameof(infoHashes));
Bitfield = new ReadOnlyBitField(bitfield);
UnhashedPieces = new ReadOnlyBitField(unhashedPieces);
for (int i = 0; i < Bitfield.Length; i++)
{
if (bitfield[i] && unhashedPieces[i])
{
throw new ArgumentException($"The bitfield is set to true at index {i} but that piece is marked as unhashed.");
}
}
}
public async Task SaveLoadFastResume()
{
await Manager.HashCheckAsync(false);
Manager.MutableBitField.SetAll(true).Set(0, false);
Manager.UnhashedPieces.SetAll(false).Set(0, true);
var origUnhashed = new ReadOnlyBitField(Manager.UnhashedPieces);
var origBitfield = new ReadOnlyBitField(Manager.Bitfield);
await Manager.LoadFastResumeAsync(await Manager.SaveFastResumeAsync());
Assert.IsTrue(origUnhashed.SequenceEqual(Manager.UnhashedPieces), "#3");
Assert.IsTrue(origBitfield.SequenceEqual(Manager.Bitfield), "#4");
}
public override int PickPiece(IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers, int startIndex, int endIndex, Span <BlockInfo> requests)
{
// Invert 'bitfield' and AND it with the peers bitfield
// Any pieces which are 'true' in the bitfield will not be downloaded
if (Bitfield.AllFalse)
{
return(base.PickPiece(peer, available, otherPeers, startIndex, endIndex, requests));
}
Temp.From(available).NAnd(Bitfield);
if (Temp.AllFalse)
{
return(0);
}
return(base.PickPiece(peer, Temp, otherPeers, startIndex, endIndex, requests));
}
public override int PickPiece(IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers, int startIndex, int endIndex, Span <BlockInfo> requests)
{
// Fast Path - the peer has nothing to offer
if (available.AllFalse || temp == null)
{
return(0);
}
// Rebuild if any file changed priority
if (ShouldRebuildSelectors())
{
BuildSelectors();
}
// Fast Path - As 'files' has been sorted highest priority first, all files
// must be set to DoNotDownload if this is true.
if (files[0].Priority == Priority.DoNotDownload)
{
return(0);
}
// Fast Path - If it's a single file, or if all the priorities are the same,
// then we can just pick normally. No prioritisation is needed.
if (files.Count == 1 || files.TrueForAll(AllSamePriority))
{
return(base.PickPiece(peer, available, otherPeers, startIndex, endIndex, requests));
}
// Start with the highest priority and work our way down.
for (int i = 0; i < prioritised.Count; i++)
{
temp.From(prioritised[i]).And(available);
if (!temp.AllFalse)
{
var result = base.PickPiece(peer, temp, otherPeers, startIndex, endIndex, requests);
if (result > 0)
{
return(result);
}
}
}
// None of the pieces from files marked as downloadable were available.
return(0);
}
public override int PickPiece(IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers, int startIndex, int endIndex, Span <BlockInfo> requests)
{
if (available.AllFalse)
{
return(0);
}
// If there's only one piece to choose then there isn't any midpoint.
if (endIndex - startIndex < 2 || requests.Length > 1)
{
return(base.PickPiece(peer, available, otherPeers, startIndex, endIndex, requests));
}
// If there are two or more pieces to choose, ensure we always start *at least* one
// piece beyond the start index.
int midpoint = Random.Next(startIndex + 1, endIndex);
var requested = base.PickPiece(peer, available, otherPeers, midpoint, endIndex, requests);
return(requested > 0 ? requested : base.PickPiece(peer, available, otherPeers, startIndex, midpoint, requests));
}
void GenerateRarestFirst(ReadOnlyBitField peerBitfield, IReadOnlyList <IPeer> otherPeers)
{
// Move anything in the rarest buffer into the spares
while (rarest.Count > 0)
{
spares.Push(rarest.Pop());
}
BitField current = (spares.Count > 0 ? spares.Pop() : new BitField(peerBitfield.Length)).From(peerBitfield);
// Store this bitfield as the first iteration of the Rarest First algorithm.
rarest.Push(current);
// Get a cloned copy of the bitfield and begin iterating to find the rarest pieces
for (int i = 0; i < otherPeers.Count; i++)
{
if (otherPeers[i].BitField.AllTrue)
{
continue;
}
current = (spares.Count > 0 ? spares.Pop() : new BitField(current.Length)).From(current);
// currentBitfield = currentBitfield & (!otherBitfield)
// This calculation finds the pieces this peer has that other peers *do not* have.
// i.e. the rarest piece.
current.NAnd(otherPeers[i].BitField);
// If the bitfield now has no pieces we've completed our task
if (current.AllFalse)
{
spares.Push(current);
break;
}
// Otherwise push the bitfield on the stack and clone it and iterate again.
rarest.Push(current);
}
}
/// <summary>
/// Creates a new BitfieldMessage
/// </summary>
/// <param name="bitfield">The bitfield to use</param>
public BitfieldMessage(ReadOnlyBitField bitfield)
{
BitField = bitfield;
CanDecode = false;
}
public static int PickPiece(this IPiecePicker picker, IPeer peer, ReadOnlyBitField available, IReadOnlyList <IPeer> otherPeers, Span <BlockInfo> requests)
{
return(picker.PickPiece(peer, available, otherPeers, 0, available.Length - 1, requests));
}
public override bool IsInteresting(IPeer peer, ReadOnlyBitField bitfield) => !Temp.From(bitfield).NAnd(Bitfield).AllFalse && base.IsInteresting(peer, Temp);
public IgnoringPicker(ReadOnlyBitField bitfield, IPiecePicker picker)
: base(picker)
{
Bitfield = bitfield;
Temp = new BitField(bitfield.Length);
}
public InitialSeedingMode(TorrentManager manager, DiskManager diskManager, ConnectionManager connectionManager, EngineSettings settings)
: base(manager, diskManager, connectionManager, settings, new InitialSeedUnchoker(manager))
{
zero = new BitField(manager.Bitfield.Length);
}