Do not simply assume we want to use the Bit Torrent downloader. It causes weird

things to happen if one is not actually running a tracker.

Fortunately this did not break everything, but having our users see
"2,147,483,647%" complete" instead of actual download progress is not an
especially graceful fallback.

src/java/com/threerings/getdown/data/Application.java

@@ -150,6 +150,15 @@ public class Application
         _config = getLocalPath(CONFIG_FILE);
     }
 
+    /**
+     * Indicates whether or not we support downloading of our resources using
+     * the Bittorrent protocol.
+     */
+    public boolean getUseTorrent ()
+    {
+        return _useTorrent;
+    }
+
     /**
      * Returns a resource that refers to the application configuration
      * file itself.
@@ -429,6 +438,9 @@ public class Application
             }
         }
 
+        // determine whether or not we should be using bit torrent
+        _useTorrent = Boolean.parseBoolean((String)cdata.get("torrent"));
+
         // look for a debug.txt file which causes us to run in java.exe on
         // Windows so that we can obtain a thread dump of the running JVM
         _windebug = getLocalPath("debug.txt").exists();
@@ -996,6 +1008,7 @@ public class Application
     protected String _class;
     protected String _name;
     protected boolean _windebug;
+    protected boolean _useTorrent = false;
 
     protected ArrayList<Resource> _codes = new ArrayList<Resource>();
     protected ArrayList<Resource> _resources = new ArrayList<Resource>();

src/java/com/threerings/getdown/launcher/Getdown.java

@@ -504,21 +504,26 @@ public abstract class Getdown extends Thread
             }
         };
 
-        Downloader dl;
-        if (resources.equals(_app.getAllResources())) {
-            ArrayList<Resource> full = new ArrayList<Resource>();
-            full.add(_app.getFullResource());
-            full.addAll(resources);
-            dl = new TorrentDownloader(full, obs);
-        } else if (resources.size() == 1 &&
-                resources.get(0).getPath().startsWith("patch")) {
-            dl = new TorrentDownloader(resources, obs);
-        } else {
-            dl = new HTTPDownloader(resources, obs);
-        }
-        dl.start();
+        // assume we're going to use an HTTP downloader
+        Downloader dl = new HTTPDownloader(resources, obs);
 
-        // now wait for it to complete
+        // if torrent downloading is enabled and we are downloading the right
+        // set of resources (a single patch file or the entire app from
+        // scratch), then use a torrent downloader instead
+        if (_app.getUseTorrent()) {
+            if (resources.equals(_app.getAllResources())) {
+                ArrayList<Resource> full = new ArrayList<Resource>();
+                full.add(_app.getFullResource());
+                full.addAll(resources);
+                dl = new TorrentDownloader(full, obs);
+            } else if (resources.size() == 1 &&
+                       resources.get(0).getPath().startsWith("patch")) {
+                dl = new TorrentDownloader(resources, obs);
+            }
+        }
+
+        // start the download and wait for it to complete
+        dl.start();
         synchronized (lock) {
             try {
                 lock.wait();