Beginnings of a debugger wire protocol

runtime/bin/dbg_connection_macos.h

Index: runtime/bin/dbg_connection_macos.h
===================================================================
--- runtime/bin/dbg_connection_macos.h	(revision 0)
+++ runtime/bin/dbg_connection_macos.h	(revision 0)
@@ -0,0 +1,44 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef BIN_DBG_CONNECTION_MACOS_H_
+#define BIN_DBG_CONNECTION_MACOS_H_
+
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <sys/socket.h>
+
+
+class DebuggerConnectionImpl {
+ public:
+  static void StartHandler(int port_number);
+
+ private:
+  enum MessageType {
+    kAddDbgFd = 1,
+    kRemoveDbgFd,
+    kQuit
+  };
+
+  struct Message {
+    MessageType msg_id;
+  };
+
+  static void SendMessage(MessageType id);
+  static bool ReceiveMessage(Message* msg);
+
+  static void SetupPollQueue();
+  static void HandleEvent(struct kevent* event);
+  static void Handler(uword args);
+
+
+
+  // File descriptors for pipes used to communicate with the debugger thread.
+  static int wakeup_fds_[2];
+  // File descriptor for the polling queue.
+  static int kqueue_fd_;
+};
+
+
+#endif  // BIN_DBG_CONNECTION_MACOS_H_