connect_test.cpp

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/*
 * Copyright (c) 2011, Willow Garage, Inc.
 * All rights reserved.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#include <stdio.h>
#include <sys/time.h>

// This is a simple speed test to compare suppressing a signal/slot
// emission by one of two methods:
//
// 1) disconnect and reconnect the signal/slot.
//
// 2) define a bool suppress_ member which makes the slot do nothing.
//
// Results for Qt 4.6 are that disconnect/reconnect takes about 11
// times as long as boolean suppressor.

#include "connect_test.h"

double now()
{
  struct timeval tv;
  gettimeofday( &tv, NULL );
  return double(tv.tv_sec) + double(tv.tv_usec) / 1000000.0;
}

int main( int argc, char **argv )
{
  MyObject* obj = new MyObject;
  obj->enableChanges();

  QObject::connect( obj, SIGNAL( changed() ), obj, SLOT( onChanged() ));
  obj->emitChanged();

  double start, end;
  int count = 1000000;

  start = now();
  for( int i = 0; i < count; i++ )
  {
    QObject::disconnect( obj, SIGNAL( changed() ), obj, SLOT( onChanged() ));
    obj->emitChanged();
    QObject::connect( obj, SIGNAL( changed() ), obj, SLOT( onChanged() ));
  }
  end = now();
  printf("disconnect/emit/connect %d times took %lf seconds.\n", count, end - start );

  obj->emitChanged();

  start = now();
  for( int i = 0; i < count; i++ )
  {
    obj->suppressChanges();
    obj->emitChanged();
    obj->enableChanges();
  }
  end = now();
  printf("suppress/emit/enable %d times took %lf seconds.\n", count, end - start );

  return 0;
}