From 05e2da7c2257a9c420c775566a403e8aaf7e10a8 Mon Sep 17 00:00:00 2001
From: ragnarok <ragnarok>
Date: Thu, 20 Oct 2005 22:05:51 +0000
Subject: [PATCH] Request pieces in rarest-first order, instead of randomly.
---
.../src/org/klomp/snark/PeerCoordinator.java | 55 +++++++++++--------
.../java/src/org/klomp/snark/Piece.java | 35 ++++++++++++
2 files changed, 68 insertions(+), 22 deletions(-)
create mode 100644 apps/i2psnark/java/src/org/klomp/snark/Piece.java
diff --git a/apps/i2psnark/java/src/org/klomp/snark/PeerCoordinator.java b/apps/i2psnark/java/src/org/klomp/snark/PeerCoordinator.java
index 3fb39ce96b..ce4a0658ac 100644
--- a/apps/i2psnark/java/src/org/klomp/snark/PeerCoordinator.java
+++ b/apps/i2psnark/java/src/org/klomp/snark/PeerCoordinator.java
@@ -69,13 +69,12 @@ public class PeerCoordinator implements PeerListener
this.storage = storage;
this.listener = listener;
- // Make a random list of piece numbers
+ // Make a list of pieces
wantedPieces = new ArrayList();
BitField bitfield = storage.getBitField();
for(int i = 0; i < metainfo.getPieces(); i++)
if (!bitfield.get(i))
- wantedPieces.add(new Integer(i));
- Collections.shuffle(wantedPieces);
+ wantedPieces.add(new Piece(i));
// Install a timer to check the uploaders.
timer.schedule(new PeerCheckerTask(this), CHECK_PERIOD, CHECK_PERIOD);
@@ -288,7 +287,7 @@ public class PeerCoordinator implements PeerListener
synchronized(wantedPieces)
{
- return wantedPieces.contains(new Integer(piece));
+ return wantedPieces.contains(new Piece(piece));
}
}
@@ -306,8 +305,10 @@ public class PeerCoordinator implements PeerListener
Iterator it = wantedPieces.iterator();
while (it.hasNext())
{
- int i = ((Integer)it.next()).intValue();
+ Piece p = (Piece)it.next();
+ int i = p.getId();
if (bitfield.get(i))
+ p.addPeer(peer);
return true;
}
}
@@ -325,28 +326,38 @@ public class PeerCoordinator implements PeerListener
synchronized(wantedPieces)
{
- Integer piece = null;
+ Piece piece = null;
+ Collections.sort(wantedPieces); // Sort in order of rarest first.
+ List requested = new ArrayList();
Iterator it = wantedPieces.iterator();
while (piece == null && it.hasNext())
{
- Integer i = (Integer)it.next();
- if (havePieces.get(i.intValue()))
+ Piece p = (Piece)it.next();
+ if (havePieces.get(p.getId()) && !p.isRequested())
{
- it.remove();
- piece = i;
+ piece = p;
}
+ else if (p.isRequested())
+ {
+ requested.add(p);
+ }
}
-
- if (piece == null)
- return -1;
-
- // We add it back at the back of the list. It will be removed
- // if gotPiece is called later. This means that the last
- // couple of pieces might very well be asked from multiple
- // peers but that is OK.
- wantedPieces.add(piece);
-
- return piece.intValue();
+
+ //Only request a piece we've requested before if there's no other choice.
+ if (piece == null) {
+ Iterator it2 = requested.iterator();
+ while (piece == null && it2.hasNext())
+ {
+ Piece p = (Piece)it2.next();
+ if (havePieces.get(p.getId()))
+ {
+ piece = p;
+ }
+ }
+ if (piece == null) return -1; //If we still can't find a piece we want, so be it.
+ }
+ piece.setRequested(true);
+ return piece.getId();
}
}
@@ -404,7 +415,7 @@ public class PeerCoordinator implements PeerListener
synchronized(wantedPieces)
{
- Integer p = new Integer(piece);
+ Piece p = new Piece(piece);
if (!wantedPieces.contains(p))
{
if (Snark.debug >= Snark.INFO)
diff --git a/apps/i2psnark/java/src/org/klomp/snark/Piece.java b/apps/i2psnark/java/src/org/klomp/snark/Piece.java
new file mode 100644
index 0000000000..d98421b992
--- /dev/null
+++ b/apps/i2psnark/java/src/org/klomp/snark/Piece.java
@@ -0,0 +1,35 @@
+package org.klomp.snark;
+
+import java.util.Set;
+import java.util.HashSet;
+
+public class Piece implements Comparable {
+
+ private int id;
+ private Set peers;
+ private boolean requested;
+
+ public Piece(int id) {
+ this.id = id;
+ this.peers = new HashSet();
+ }
+
+ public int compareTo(Object o) throws ClassCastException {
+ return this.peers.size() - ((Piece)o).peers.size();
+ }
+
+ public boolean equals(Object o) {
+ if (o == null) return false;
+ try {
+ return this.id == ((Piece)o).id;
+ } catch (ClassCastException cce) {
+ return false;
+ }
+ }
+
+ public int getId() { return this.id; }
+ public Set getPeers() { return this.peers; }
+ public boolean addPeer(Peer peer) { return this.peers.add(peer.getPeerID()); }
+ public boolean isRequested() { return this.requested; }
+ public void setRequested(boolean requested) { this.requested = requested; }
+}
--
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