Make Scheme hooks and timers threadsafe

[clinton/bobotpp.git] / source / BotInterp.C

// BotInterp.C  -*- C++ -*-
// Copyright (c) 1998 Etienne BERNARD
// Copyright (C) 2002,2005,2008 Clinton Ebadi

// This program 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 2 of the License, or
// (at your option) any later version.

// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
// 02110-1301, USA.

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <algorithm>

#include "Utils.H"
#include "Bot.H"
#include "BotInterp.H"

#ifdef USESCRIPTS

#include <libguile.h>
extern "C"
{
#include <libguile/regex-posix.h>
}

BotInterp::BotInterp(Bot *b, String fn)
  : bot(b), counter(0), timer_mutex (true)
{
  logPort = scm_open_file (Utils::str2scm (fn),
                           Utils::str2scm ("a"));

  scm_gc_protect_object(logPort);
}

void
BotInterp::Execute(String command)
{
  Interp::Execute(bot, command);
}

void
BotInterp::LoadScript(String filename)
{
  Interp::LoadScript(bot, filename);
}

SCM
BotInterp::ScriptLog()
{
  return logPort;
}

namespace
{
  bool hptr_lt (const Hook* h, const Hook* h1)
    // Hook Pointer less than
    // Used to sort the Hooks list
  { return *h < *h1; }
}

bool
BotInterp::AddHook(int hooktype, SCM regex, SCM function, int pri, bool fall,
		   String name) 
{
  if (scm_string_p(regex) == SCM_BOOL_F)
    return false;
  String rx = Utils::to_upper (Utils::scm2str (regex));
  // fixme: really ought to use scm_c_module_lookup with bot module
  SCM r = scm_make_regexp (regex,
			   scm_list_n (scm_variable_ref (scm_c_lookup ("regexp/icase")),
				       SCM_UNDEFINED));
  scm_gc_protect_object(r);
  scm_gc_protect_object(function);

  BotLock hook_lock (hook_mutex);

  // First, we check if an hook doesn't exist yet
  std::list<Hook *>::iterator it = hooksMap[hooktype].begin();
  std::list<Hook *>::iterator it2 = hooksMap[hooktype].end();

  for ( ; it != it2; ++it)
    // It exists, we replace it.
    if ((*it)->regex_str == rx && (*it)->name == name) {
      scm_gc_unprotect_object((*it)->function);
      scm_gc_unprotect_object (r);
      (*it)->function = function;
      (*it)->priority = pri;
      (*it)->fallthru = fall;
      hooksMap[hooktype].sort (hptr_lt);
      return true;
    }
  // It does not exist, we create it
  hooksMap[hooktype].push_back (new Hook(hooktype, rx, r, 
					 function, pri, fall, name));
  hooksMap[hooktype].sort (hptr_lt);
  return true;
}

bool
BotInterp::RunHooks(int hooktype, String match, SCM args)
{
  BotLock hook_lock (hook_mutex);

  SCM result;

  // We want to execute higher priority hooks first, so we start at
  // the end of the list instead of the beggining
  std::list<Hook *>::reverse_iterator it = hooksMap[hooktype].rbegin();
  std::list<Hook *>::reverse_iterator it2 = hooksMap[hooktype].rend();

  wrapper_data wd;
  wd.args = args;

  for ( ; it != it2; ++it) {
    if (scm_regexp_exec((*it)->regex, Utils::str2scm (match),
                        SCM_UNDEFINED, SCM_UNDEFINED) != SCM_BOOL_F)
      {
	wd.func = (*it)->function;
	result = scm_internal_catch(SCM_BOOL_T, 
				    (scm_t_catch_body) 
				    Interp::LazyApplyWrapper,
				    static_cast<void *> (&wd), 
				    (scm_t_catch_handler) Interp::EmptyHandler, 0);
	if (! (*it)->fallthru)
	  break;
    }
  }

  return true;
}

SCM
BotInterp::AddTimer(int delay, SCM function)
{
  BotLock timer_lock (timer_mutex);  
  int when = time(NULL) + delay;

  scm_gc_protect_object(function);

  Timer *timer = new Timer (++counter, when, function);
  TimerList::iterator it = std::find_if (timers.begin (), timers.end (),
					 std::bind1st (timer_sort_p, timer));
  
  if (it != timers.end ())
    timers.insert (it, timer);
  else
    timers.push_back (timer);

  return scm_from_int (counter);

}

bool
BotInterp::DelTimer(SCM timer)
{
  BotLock timer_lock (timer_mutex);

  int count = scm_to_int (timer);
  TimerList::iterator it = timers.begin();
  TimerList::iterator end = timers.end();

  for ( ; it != end; ++it) 
    {
      if ((*it)->count == count) 
	{
	  scm_gc_unprotect_object((*it)->function);
	  delete (*it);
	  timers.erase(it);

	  return true;
	}
    }

  return false;
}

bool
BotInterp::RunTimers(int now)
{
  BotLock timer_lock (timer_mutex);
  struct wrapper_data wd;
  wd.args = scm_list_n (SCM_UNDEFINED);

  while (!timers.empty ())
    {
      // Keep a stack allocated copy of the front of the timer queue
      // just in case the timer is deleted while being executed (which
      // is very unlikely as the only place this could occur is if the
      // timer deleted itself)
      Timer current_timer = *timers.front () ; 

      if (current_timer.when <= now) 
	{
	  wd.func = current_timer.function;

	  scm_internal_catch (SCM_BOOL_T,
			      (scm_t_catch_body) Interp::LazyApplyWrapper,
			      (void *)&wd,
			      (scm_t_catch_handler) Interp::EmptyHandler, 
			      0);

	  // The timer list may have been modified by the timer
	  // callback; if it has in such a way that the first queue
	  // item has changed (adding a timer in the past) then we
	  // switch the slow path for deleting a timer
	  if (current_timer.count == timers.front()->count)
	    {
	      scm_gc_unprotect_object (current_timer.function);
	      delete timers.front ();
	      timers.pop_front ();
	    }
	  else
	    {
	      DelTimer (scm_from_int (current_timer.count));
	    }
	} 
      else 
	{
	  break;
	}
    }

  return true;
}

#endif