Make host_forwarder better handle duplicate forwards.

tools/android/forwarder2/host_forwarder_main.cc

Index: tools/android/forwarder2/host_forwarder_main.cc
diff --git a/tools/android/forwarder2/host_forwarder_main.cc b/tools/android/forwarder2/host_forwarder_main.cc
index 82bb7a841b7fba5db25de5fe28f8e51758e410f3..56172736653c09e0938ace70dc0f4b896205a8d9 100644
--- a/tools/android/forwarder2/host_forwarder_main.cc
+++ b/tools/android/forwarder2/host_forwarder_main.cc
@@ -134,6 +134,14 @@ class ServerDelegate : public Daemon::ServerDelegate {
       SendMessage("ERROR: missing host port", client_socket.get());
       return;
     }
+    const std::string controller_key = MakeHostControllerMapKey(
+        adb_port, device_port);
+    if (controllers_.find(controller_key) != controllers_.end()) {
+      // The port is already forwarded.

[bulach, 2013/07/08 14:35:36]

nit: maybe expand this a little bit, and add a log to differentiate from 156
below?

// The host already knows about this forward.
// The device side may have been restarted, so
// send the message again to reestablish the link.
LOG(INFO) << "Re-forwarding device port " << device_port << " to host port " <<
host_port;

[Philippe, 2013/07/08 15:47:50]

Note that this wasn't unfortunately doing what your (C++) comment is saying :)
I'm preparing a more robust patch set to follow your comment.

[Philippe, 2013/07/08 17:00:38]

The other patch set I mentioned is a much bigger change. I would like to land
this one before to fix the build downstream if that's ok with you.

[bulach, 2013/07/08 17:40:35]

sgtm.. would you like to add the LOG just in case, so at least we'll have some
information to distinguish the cases?

+      SendMessage(base::StringPrintf("%d:%d", device_port, host_port),
+                  client_socket.get());
+      return;
+    }
     // Create a new host controller.
     scoped_ptr<HostController> host_controller(
         new HostController(device_port, "127.0.0.1", host_port, adb_port,
@@ -151,8 +159,6 @@ class ServerDelegate : public Daemon::ServerDelegate {
     if (!SendMessage(msg, client_socket.get()))
       return;
     host_controller->Start();
-    const std::string controller_key = MakeHostControllerMapKey(
-        adb_port, device_port);
     controllers_.insert(
         std::make_pair(controller_key,
                        linked_ptr<HostController>(host_controller.release())));