i2psnark: Cache length of metainfo

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

@@ -49,7 +49,7 @@ class MagnetState {
         infohash = iHash;
         if (meta != null) {
             metainfo = meta;
-            initialize(meta.getInfoBytes().length);
+            initialize(meta.getInfoBytesLength());
             complete = true;
         }
     }

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

@@ -68,6 +68,7 @@ public class MetaInfo
   private final String created_by;
   private final long creation_date;
   private Map<String, BEValue> infoMap;
+  private int infoBytesLength;
 
   /**
    *  Called by Storage when creating a new torrent from local data
@@ -622,11 +623,27 @@ public class MetaInfo
         return BEncoder.bencode(m);
   }
 
-  /** @since 0.8.4 */
+  /**
+   *  Side effect: Caches infoBytesLength.
+   *  @since 0.8.4
+   */
   public synchronized byte[] getInfoBytes() {
     if (infoMap == null)
         createInfoMap();
-    return BEncoder.bencode(infoMap);
+    byte[] rv = BEncoder.bencode(infoMap);
+    infoBytesLength = rv.length;
+    return rv;
+  }
+
+  /**
+   *  The size of getInfoBytes().
+   *  Cached.
+   *  @since 0.9.48
+   */
+  public synchronized int getInfoBytesLength() {
+    if (infoBytesLength > 0)
+        return infoBytesLength;
+    return getInfoBytes().length;
   }
 
   /** @return an unmodifiable view of the Map */

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

@@ -290,7 +290,7 @@ public class Peer implements Comparable<Peer>
         if ((options & OPTION_EXTENSION) != 0) {
             if (_log.shouldLog(Log.DEBUG))
                 _log.debug("Peer supports extensions, sending reply message");
-            int metasize = metainfo != null ? metainfo.getInfoBytes().length : -1;
+            int metasize = metainfo != null ? metainfo.getInfoBytesLength() : -1;
             boolean pexAndMetadata = metainfo == null || !metainfo.isPrivate();
             boolean dht = util.getDHT() != null;
             boolean comment = util.utCommentsEnabled();