--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libinterp/interpfcn/octave-link.h	Wed Apr 03 23:16:37 2013 -0400
@@ -0,0 +1,248 @@
+/*
+
+Copyright (C) 2013 John W. Eaton
+Copyright (C) 2011-2012 Jacob Dawid
+Copyright (C) 2011-2012 John P. Swensen
+
+This file is part of Octave.
+
+Octave is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+Octave is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Octave; see the file COPYING.  If not, see
+<http://www.gnu.org/licenses/>.
+
+*/
+
+#if !defined (octave_link_h)
+#define octave_link_h 1
+
+#include <string>
+
+#include "event-queue.h"
+#include "octave-event-listener.h"
+
+class octave_mutex;
+
+// \class OctaveLink
+// \brief Provides threadsafe access to octave.
+// \author Jacob Dawid
+//
+// This class is a wrapper around octave and provides thread safety by
+// buffering access operations to octave and executing them in the
+// readline event hook, which lives in the octave thread.
+
+class octave_link
+{
+protected:
+
+  octave_link (void);
+
+public:
+
+  virtual ~octave_link (void) { }
+
+  static void register_event_listener (octave_event_listener *el)
+  {
+    if (instance_ok ())
+      instance->do_register_event_listener (el);
+  }
+
+  static void generate_events (void)
+  {
+    if (instance_ok ())
+      instance->do_generate_events ();
+  }
+
+  static void process_events (void)
+  {
+    if (instance_ok ())
+      instance->do_process_events ();
+  }
+
+  template <class T>
+  static void post_event (T *obj, void (T::*method) (void))
+  {
+    if (instance_ok ())
+      instance->do_post_event (obj, method);
+  }
+
+  template <class T, class A>
+  static void post_event (T *obj, void (T::*method) (A), A arg)
+  {
+    if (instance_ok ())
+      instance->do_post_event (obj, method, arg);
+  }
+
+  template <class T, class A>
+  static void post_event (T *obj, void (T::*method) (const A&), const A& arg)
+  {
+    if (instance_ok ())
+      instance->do_post_event (obj, method, arg);
+  }
+
+  static void about_to_exit (void)
+  {
+    if (instance_ok ())
+      instance->do_about_to_exit ();
+  }
+
+  static void entered_readline_hook (void)
+  {
+    if (instance_ok ())
+      instance->do_entered_readline_hook ();
+  }
+
+  static void finished_readline_hook (void)
+  {
+    if (instance_ok ())
+      instance->do_finished_readline_hook ();
+  }
+
+  static std::string last_working_directory (void)
+  {
+    return instance_ok ()
+      ? instance->do_last_working_directory () : std::string ();
+  }
+
+  static void update_workspace (void)
+  {
+    if (instance_ok ())
+      instance->do_update_workspace ();
+  }
+
+  static void update_history (void)
+  {
+    if (instance_ok ())
+      instance->do_update_history ();
+  }
+
+  static void pre_input_event (void)
+  {
+    if (instance_ok ())
+      instance->do_pre_input_event ();
+  }
+
+  static void post_input_event (void)
+  {
+    if (instance_ok ())
+      instance->do_post_input_event ();
+  }
+
+  static void enter_debugger_event (const std::string& file, int line)
+  {
+    if (instance_ok ())
+      instance->do_enter_debugger_event (file, line);
+  }
+
+  static void exit_debugger_event (const std::string& file, int line)
+  {
+    if (instance_ok ())
+      instance->do_exit_debugger_event (file, line);
+  }
+
+  static void
+  update_breakpoint (bool insert, const std::string& file, int line)
+  {
+    if (instance_ok ())
+      instance->do_update_breakpoint (insert, file, line);
+  }
+
+  static bool
+  edit_file (const std::string& file)
+  {
+    return instance_ok () ? instance->do_edit_file (file) : false;
+  }
+
+  static void connect (octave_link *);
+
+private:
+
+  static octave_link *instance;
+
+  static void cleanup_instance (void) { delete instance; instance = 0; }
+
+  // No copying!
+
+  octave_link (const octave_link&);
+
+  octave_link& operator = (const octave_link&);
+
+  static bool instance_ok (void);
+
+protected:
+
+  octave_event_listener *event_listener;
+
+  // Semaphore to lock access to the event queue.
+  octave_mutex *event_queue_mutex;
+
+  // Event Queue.
+  event_queue gui_event_queue;
+
+  // Stores the last known current working directory of octave.
+  std::string last_cwd;
+
+  bool debugging;
+
+  void do_register_event_listener (octave_event_listener *oel);
+
+  void do_generate_events (void);
+  void do_process_events (void);
+
+  template <class T>
+  void do_post_event (T *obj, void (T::*method) (void))
+  {
+    gui_event_queue.add_method (obj, method);
+  }
+
+  template <class T, class A>
+  void do_post_event (T *obj, void (T::*method) (A), A arg)
+  {
+    gui_event_queue.add_method (obj, method, arg);
+  }
+
+  template <class T, class A>
+  void do_post_event (T *obj, void (T::*method) (const A&), const A& arg)
+  {
+    gui_event_queue.add_method (obj, method, arg);
+  }
+
+  void do_about_to_exit (void);
+
+  void do_entered_readline_hook (void) { }
+  void do_finished_readline_hook (void) { }
+
+  std::string do_last_working_directory (void);
+
+  virtual void do_update_workspace (void) = 0;
+
+  virtual void do_update_history (void) = 0;
+
+  virtual void
+  do_insert_debugger_pointer (const std::string& file, int line) = 0;
+
+  virtual void
+  do_delete_debugger_pointer (const std::string& file, int line) = 0;
+
+  virtual void do_pre_input_event (void) = 0;
+  virtual void do_post_input_event (void) = 0;
+
+  virtual void do_enter_debugger_event (const std::string& file, int line) = 0;
+  virtual void do_exit_debugger_event (const std::string& file, int line) = 0;
+
+  virtual void do_update_breakpoint (bool insert,
+                                     const std::string& file, int line) = 0;
+
+  virtual bool do_edit_file (const std::string& file) = 0;
+};
+
+#endif // OCTAVELINK_H