i2psnark: Add support for fast extensions (BEP 6)

untested

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

@@ -155,10 +155,17 @@ class PeerState implements DataLoader
       setInteresting(true);
   }
 
-  void bitfieldMessage(byte[] bitmap)
-  {
-    synchronized(this)
-      {
+  void bitfieldMessage(byte[] bitmap) {
+      bitfieldMessage(bitmap, false);
+  }
+
+  /**
+   *  @param bitmap null to use the isAll param
+   *  @param isAll only if bitmap == null: true for have_all, false for have_none
+   *  @since 0.9.21
+   */
+  private void bitfieldMessage(byte[] bitmap, boolean isAll) {
+    synchronized(this) {
         if (_log.shouldLog(Log.DEBUG))
           _log.debug(peer + " rcv bitfield");
         if (bitfield != null)
@@ -172,10 +179,24 @@ class PeerState implements DataLoader
         // XXX - Check for weird bitfield and disconnect?
         // FIXME will have to regenerate the bitfield after we know exactly
         // how many pieces there are, as we don't know how many spare bits there are.
-        if (metainfo == null)
-            bitfield = new BitField(bitmap, bitmap.length * 8);
-        else
-            bitfield = new BitField(bitmap, metainfo.getPieces());
+        if (metainfo == null) {
+            if (bitmap != null) {
+                bitfield = new BitField(bitmap, bitmap.length * 8);
+            } else {
+                // we can't handle this situation
+                if (_log.shouldLog(Log.WARN))
+                    _log.warn("have_x w/o metainfo: " + isAll);
+                return;
+            }
+        } else {
+            if (bitmap != null) {
+                bitfield = new BitField(bitmap, metainfo.getPieces());
+            } else {
+                bitfield = new BitField(metainfo.getPieces());
+                if (isAll)
+                    bitfield.setAll();
+            }
+        }
       }
     if (metainfo == null)
         return;
@@ -198,12 +219,17 @@ class PeerState implements DataLoader
                   + piece + ", " + begin + ", " + length + ") ");
     if (metainfo == null)
         return;
-    if (choking)
-      {
-        if (_log.shouldLog(Log.INFO))
-          _log.info("Request received, but choking " + peer);
+    if (choking) {
+        if (peer.supportsFast()) {
+            if (_log.shouldInfo())
+              _log.info("Request received, sending reject to choked " + peer);
+            out.sendReject(piece, begin, length);
+        } else {
+            if (_log.shouldInfo())
+              _log.info("Request received, but choking " + peer);
+        }
         return;
-      }
+    }
 
     // Sanity check
     if (piece < 0
@@ -227,8 +253,14 @@ class PeerState implements DataLoader
     // Todo: limit number of requests also? (robert 64 x 4KB)
     if (out.queuedBytes() + length > MAX_PIPELINE_BYTES)
       {
-        if (_log.shouldLog(Log.WARN))
-          _log.warn("Discarding request over pipeline limit from " + peer);
+        if (peer.supportsFast()) {
+            if (_log.shouldWarn())
+                _log.warn("Rejecting request over pipeline limit from " + peer);
+            out.sendReject(piece, begin, length);
+        } else {
+            if (_log.shouldWarn())
+                _log.warn("Discarding request over pipeline limit from " + peer);
+        }
         return;
       }
 
@@ -536,6 +568,58 @@ class PeerState implements DataLoader
       listener.gotPort(peer, port, port + 1);
   }
 
+  /////////// fast message handlers /////////
+
+  /**
+   *  BEP 6
+   *  Treated as "have" for now
+   *  @since 0.9.21
+   */
+  void suggestMessage(int piece) {
+      if (_log.shouldInfo()) 
+          _log.info("Handling suggest as have(" + piece + ") from " + peer);
+      haveMessage(piece);
+  }
+
+  /**
+   *  BEP 6
+   *  @param isAll true for have_all, false for have_none
+   *  @since 0.9.21
+   */
+  void haveMessage(boolean isAll) {
+      bitfieldMessage(null, isAll);
+  }
+
+  /**
+   *  BEP 6
+   *  @since 0.9.21
+   */
+  void rejectMessage(int piece, int begin, int length) {
+      if (_log.shouldInfo()) 
+           _log.info("Got reject(" + piece + ',' + begin + ',' + length + ") from " + peer);
+      out.cancelRequest(piece, begin, length);
+      synchronized(this) {
+          for (Iterator<Request> iter = outstandingRequests.iterator(); iter.hasNext(); ) {
+              Request req = iter.next();
+              if (req.getPiece() == piece && req.off == begin && req.len == length)
+                  iter.remove();
+          }
+          if (lastRequest != null && lastRequest.getPiece() == piece &&
+              lastRequest.off == begin && lastRequest.len == length)
+              lastRequest = null;
+      }
+  }
+
+  /**
+   *  BEP 6
+   *  Ignored for now
+   *  @since 0.9.21
+   */
+  void allowedFastMessage(int piece) {
+      if (_log.shouldInfo()) 
+          _log.info("Ignoring allowed_fast(" + piece + ") from " + peer);
+  }
+
   void unknownMessage(int type, byte[] bs)
   {
     if (_log.shouldLog(Log.WARN))
@@ -543,6 +627,8 @@ class PeerState implements DataLoader
                   + " length: " + bs.length);
   }
 
+  /////////// end message handlers /////////
+
   /**
    *  We now have this piece.
    *  Tell the peer and cancel any requests for the piece.