connect_test.cpp

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/*
 * Copyright (c) 2011, Willow Garage, Inc.
 * All rights reserved.
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#include <stdio.h>
#include <chrono>
 
// 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"
 
int main(int /*argc*/, char** /*argv*/)
{
  MyObject* obj = new MyObject;
  obj->enableChanges();
 
  QObject::connect(obj, SIGNAL(changed()), obj, SLOT(onChanged()));
  obj->emitChanged();
 
  int count = 1000000;
 
  auto start = std::chrono::steady_clock::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()));
  }
  auto end = std::chrono::steady_clock::now();
  printf("disconnect/emit/connect %d times took %lf seconds.\n", count,
         std::chrono::duration<double>(end - start).count());
 
  obj->emitChanged();
 
  start = std::chrono::steady_clock::now();
  for (int i = 0; i < count; i++)
  {
    obj->suppressChanges();
    obj->emitChanged();
    obj->enableChanges();
  }
  end = std::chrono::steady_clock::now();
  printf("suppress/emit/enable %d times took %lf seconds.\n", count,
         std::chrono::duration<double>(end - start).count());
 
  return 0;
}