// -*- C++ -*-
// EPOS-- Synchronizer Abstractions Common Package

// This work is licensed under the Creative Commons 
// Attribution-NonCommercial-NoDerivs License. To view a copy of this license, 
// visit http://creativecommons.org/licenses/by-nc-nd/2.0/ or send a letter to 
// Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.

#ifndef __synchronizer_h
#define __synchronizer_h

#include <system/config.h>
#include <utility/queue.h> //EX2: inclui a nossa fila!
#include <cpu.h>
#include <thread.h>

__BEGIN_SYS

class Synchronizer_Common
{
 protected:
  Synchronizer_Common() {}
  virtual ~Synchronizer_Common() {
	db<Synchronizer_Common>(TRC) << "~Synchronizer_Common()\n";
	wakeup_all();
  }

 private:
  static const bool busy_waiting = Traits<Thread>::busy_waiting;
  typedef Queue<Thread> FIFOQueue;

 protected:
  FIFOQueue _sleepers; //EX2: definicao da fila de dorminhocos

 protected:
  // Atomic operations
  bool tsl(volatile bool & lock) { return CPU::tsl(lock); }
  int inc(volatile int & number) { return CPU::finc(number); }
  int dec(volatile int & number) { return CPU::fdec(number); }

  // Thread operations
  void sleep() {
	if(!busy_waiting){ // configurable feature
	  Thread::sleep(&_sleepers); //EX2: chama o metodo estatico de Thread para colocar running na fila e dormir
	}
  }
  void wakeup() {
	if(!busy_waiting){    	// configurable feature
	  Thread::wakeup(&_sleepers); //EX2: chama o metodo estatico de Thread para acordar o primeiro da fila
	}
  }
  void wakeup_all() {
	if(!busy_waiting){ // configurable feature
	  Thread::wakeup_all(&_sleepers); //EX2: chama o metodo estatico de Thread para acordar todos da fila
	}
  }
};

__END_SYS

#endif