i2psnark: Periodically connect out to other seeds to fetch comments (ticket #2288)

javadoc updates

apps/i2psnark/java/src/org/klomp/snark/PeerCoordinator.java

@@ -30,7 +30,6 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.Random;
 import java.util.Set;
 import java.util.concurrent.LinkedBlockingDeque;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -43,6 +42,7 @@ import net.i2p.data.Destination;
 import net.i2p.util.ConcurrentHashSet;
 import net.i2p.util.I2PAppThread;
 import net.i2p.util.Log;
+import net.i2p.util.RandomSource;
 import net.i2p.util.SimpleTimer2;
 
 import org.klomp.snark.bencode.BEValue;
@@ -145,7 +145,13 @@ class PeerCoordinator implements PeerListener
   private final MagnetState magnetState;
   private final CoordinatorListener listener;
   private final I2PSnarkUtil _util;
-  private final Random _random;
+  private final RandomSource _random;
+
+  private final AtomicLong _commentsLastRequested = new AtomicLong();
+  private final AtomicInteger _commentsNotRequested = new AtomicInteger();
+  private static final long COMMENT_REQ_INTERVAL = 12*60*60*1000L;
+  private static final long COMMENT_REQ_DELAY = 60*60*1000L;
+  private static final int MAX_COMMENT_NOT_REQ = 10;
   
   /**
    *  @param metainfo null if in magnet mode
@@ -176,6 +182,9 @@ class PeerCoordinator implements PeerListener
     // this will help the behavior with global limits
     timer = new CheckEvent(_util.getContext(), new PeerCheckerTask(_util, this));
     timer.schedule((CHECK_PERIOD / 2) + _random.nextInt((int) CHECK_PERIOD));
+
+    // we don't store the last-requested time, so just delay a random amount
+    _commentsLastRequested.set(util.getContext().clock().now() - (COMMENT_REQ_INTERVAL - _random.nextLong(COMMENT_REQ_DELAY)));
   }
   
   /**
@@ -329,7 +338,8 @@ class PeerCoordinator implements PeerListener
   }
 
   /**
-   * Returns the 4-minute-average rate in Bps
+   * Returns the average rate in Bps
+   * over last RATE_DEPTH * CHECK_PERIOD seconds
    */
   public long getDownloadRate()
   {
@@ -338,6 +348,10 @@ class PeerCoordinator implements PeerListener
     return getRate(downloaded_old);
   }
 
+  /**
+   * Returns the average rate in Bps
+   * over last RATE_DEPTH * CHECK_PERIOD seconds
+   */
   public long getUploadRate()
   {
     if (halted)
@@ -345,6 +359,10 @@ class PeerCoordinator implements PeerListener
     return getRate(uploaded_old);
   }
 
+  /**
+   * Returns the rate in Bps
+   * over last complete CHECK_PERIOD seconds
+   */
   public long getCurrentUploadRate()
   {
     if (halted)
@@ -404,7 +422,12 @@ class PeerCoordinator implements PeerListener
   public boolean needOutboundPeers() {
         //return wantedBytes != 0 && needPeers();
         // minus two to make it a little easier for new peers to get in on large swarms
-        return wantedBytes != 0 &&
+        return (wantedBytes != 0 ||
+                (_util.utCommentsEnabled() &&
+                 // we should also check SnarkManager.getSavedCommentsEnabled() for this torrent,
+                 // but that reads in the config file, there's no caching.
+                 // TODO
+                 _commentsLastRequested.get() < _util.getContext().clock().now() - COMMENT_REQ_INTERVAL)) &&
                !halted &&
                peers.size() < getMaxConnections() - 2 &&
                (storage == null || !storage.isChecking());
@@ -617,6 +640,8 @@ class PeerCoordinator implements PeerListener
             bitfield = storage.getBitField();
         else
             bitfield = null;
+        if (!peer.isIncoming() && wantedBytes == 0 && _log.shouldInfo())
+            _log.info("Outbound connection as seed to get comments for " + snark.getBaseName() + " to " + peer);
         // if we aren't a seed but we don't want any more
         final boolean partialComplete = wantedBytes == 0 && bitfield != null && !bitfield.complete();
         Runnable r = new Runnable()
@@ -1447,11 +1472,17 @@ class PeerCoordinator implements PeerListener
    */
   void sendCommentReq(Peer peer) {
       Map<String, BEValue> handshake = peer.getHandshakeMap();
-      if (handshake == null)
+      if (handshake == null) {
+          if (wantedBytes == 0 && _commentsNotRequested.incrementAndGet() >= MAX_COMMENT_NOT_REQ)
+              _commentsLastRequested.set(_util.getContext().clock().now());
           return;
+      }
       BEValue bev = handshake.get("m");
-      if (bev == null)
+      if (bev == null) {
+          if (wantedBytes == 0 && _commentsNotRequested.incrementAndGet() >= MAX_COMMENT_NOT_REQ)
+              _commentsLastRequested.set(_util.getContext().clock().now());
           return;
+      }
       // TODO if peer hasn't been connected very long, don't bother
       // unless forced at handshake time (see above)
       try {
@@ -1463,9 +1494,16 @@ class PeerCoordinator implements PeerListener
                       sz = comments.size();
                   }
               }
+              _commentsNotRequested.set(0);
+              _commentsLastRequested.set(_util.getContext().clock().now());
               if (sz >= CommentSet.MAX_SIZE)
                   return;
               ExtensionHandler.sendCommentReq(peer, CommentSet.MAX_SIZE - sz);
+          } else {
+              // failsafe to prevent seed excessively connecting out to a swarm for comments
+              // when nobody in the swarm supports comments
+              if (wantedBytes == 0 && _commentsNotRequested.incrementAndGet() >= MAX_COMMENT_NOT_REQ)
+                  _commentsLastRequested.set(_util.getContext().clock().now());
           }
       } catch (InvalidBEncodingException ibee) {}
   }
@@ -1671,6 +1709,9 @@ class PeerCoordinator implements PeerListener
       interestedAndChoking.addAndGet(toAdd);
   }
 
+  /**
+   *  Is snark as a whole over its limit?
+   */
   public boolean overUpBWLimit()
   {
     if (listener != null)
@@ -1678,6 +1719,10 @@ class PeerCoordinator implements PeerListener
     return false;
   }
 
+  /**
+   *  Is a particular peer who has downloaded this many bytes from us
+   *  in the last CHECK_PERIOD over its limit?
+   */
   public boolean overUpBWLimit(long total)
   {
     if (listener != null)