i2psnark: Throttle torrent startup to prevent OOMs

for a large number torrents
ref: http://zzz.i2p/topics/3475

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

@@ -2899,6 +2899,7 @@ public class SnarkManager implements CompleteListener, ClientApp, DisconnectList
         //if (_log.shouldLog(Log.DEBUG))
         //    _log.debug("DirMon found: " + DataHelper.toString(foundNames) + " existing: " + DataHelper.toString(existingNames));
         // lets find new ones first...
+        int count = 0;
         for (String name : foundNames) {
             if (existingNames.contains(name)) {
                 // already known.  noop
@@ -2926,6 +2927,10 @@ public class SnarkManager implements CompleteListener, ClientApp, DisconnectList
                     disableTorrentFile(name);
                     rv = false;
                 }
+                if (shouldStart && (count++ & 0x0f) == 15) {
+                    // try to prevent OOMs at startup
+                    try { Thread.sleep(250); } catch (InterruptedException ie) {}
+                }
             }
         }
         // Don't remove magnet torrents that don't have a torrent file yet
@@ -3105,21 +3110,19 @@ public class SnarkManager implements CompleteListener, ClientApp, DisconnectList
     }
 
     /**
-     *  If not connected, thread it, otherwise inline
+     *  Always thread it
      *  @since 0.9.1
      */
     public void startAllTorrents() {
-        if (_util.connected()) {
-            startAll();
-        } else {
+        if (!_util.connected()) {
             addMessage(_t("Opening the I2P tunnel and starting all torrents."));
             for (Snark snark : _snarks.values()) {
                 // mark it for the UI
                 snark.setStarting();
             }
-            (new I2PAppThread(new ThreadedStarter(null), "TorrentStarterAll", true)).start();
-            try { Thread.sleep(200); } catch (InterruptedException ie) {}
         }
+        (new I2PAppThread(new ThreadedStarter(null), "TorrentStarterAll", true)).start();
+        try { Thread.sleep(200); } catch (InterruptedException ie) {}
     }
 
     /**
@@ -3149,6 +3152,7 @@ public class SnarkManager implements CompleteListener, ClientApp, DisconnectList
      *  @since 0.9.1
      */
     private void startAll() {
+        int count = 0;
         for (Snark snark : _snarks.values()) {
             if (snark.isStopped()) {
                 try {
@@ -3156,6 +3160,10 @@ public class SnarkManager implements CompleteListener, ClientApp, DisconnectList
                 } catch (RuntimeException re) {
                     // Snark.fatal() will log and call fatal() here for user message before throwing
                 }
+                if ((count++ & 0x0f) == 15) {
+                    // try to prevent OOMs
+                    try { Thread.sleep(250); } catch (InterruptedException ie) {}
+                }
             }
         }
     }