macedon_lock.cc

这是一个著名的应用层组播中间件的源码

//Copyright (c) 2004, Charles Killian, Adolfo Rodriguez, Dejan Kostic, Sooraj Bhat, and Amin Vahdat
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in
//     the documentation and/or other materials provided with the
//     distribution.
//   * Neither the names of Duke University nor The University of
//     California, San Diego, nor the names of its contributors
//     may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
//AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
//IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
//FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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/*  

Common Macedon lock routines.

Adolfo Rodriguez



*/
#include "macedon.h"
#include "macedon-macros.h"

#define MACEDON_TRACE_LOCK

#define MACEDON_LOCK_ON                       10
#define MACEDON_LOCK_OFF                     -10


/*
 * set and unset and test lock operations.
 */
void MACEDON_Agent::lock_on( int s )
{
  double curtime = Scheduler::instance().clock();
  lockstr_.lock_           = MACEDON_LOCK_ON;
  lockstr_.source_of_lock_ = s;
  lockstr_.time_of_lock_ = curtime;
  
#ifdef MACEDON_TRACE_LOCK
  debug_macro("Lock: locked by %x.\n", lockstr_.source_of_lock_);
#endif
}


void MACEDON_Agent::lock_off ( )
{
  // unlock myself
  lockstr_.lock_           = MACEDON_LOCK_OFF;
  
#ifdef MACEDON_TRACE_LOCK
  debug_macro("Lock: unlocked by %x\n", lockstr_.source_of_lock_ );
#endif
  
  lockstr_.source_of_lock_ = 0;
}



int MACEDON_Agent::test_lock()
{
  return ( lockstr_.lock_ );
}


int MACEDON_Agent::test_lock_source()
{
  return ( lockstr_.source_of_lock_ );
}