QMap to keep the model statistcs

**wysota** · 10th December 2007, 15:59

Memory leak? How do you know you have a memory leak?

How does the application behave?

**gyre** · 10th December 2007, 16:06

Originally Posted by wysota

Memory leak? How do you know you have a memory leak?

How does the application behave?

it exits with the following error log...
*** glibc detected *** /home/gyre/temp/06_filter_widget_added/bin/qcanalyzer: realloc(): invalid old size: 0x080dbf38 ***
======= Backtrace: =========
/lib/libc.so.6[0xb734dbdd]
/lib/libc.so.6(realloc+0xfe)[0xb734fb4e]
/usr/lib/libQtCore.so.4(_Z8qReallocPvj+0x24)[0xb7597bf8]
/usr/lib/libQtCore.so.4(_ZN7QString7reallocEi+0x24c)[0xb75df3b4]
/usr/lib/libQtCore.so.4(_ZN7QString6appendE5QChar+0x78)[0xb75e099a]
/usr/lib/libQtCore.so.4[0xb759abba]
/usr/lib/libQtCore.so.4[0xb7613e14]
/usr/lib/libQtCore.so.4[0xb7610a3d]
/usr/lib/libQtCore.so.4[0xb761104c]
/usr/lib/libQtCore.so.4[0xb7611498]
/usr/lib/libQtCore.so.4(_ZNK9QResource12isCompressedEv+0x1f )[0xb7611717]
/usr/lib/libQtCore.so.4[0xb7611929]
/usr/lib/libQtCore.so.4[0xb7611a4a]
/usr/lib/libQtCore.so.4(_ZN19QAbstractFileEngine6createERK7 QString+0x5b)[0xb75ea4eb]
/usr/lib/libQtCore.so.4[0xb75fe9d9]
/usr/lib/libQtCore.so.4(_ZN9QFileInfoC1ERK7QString+0x4a)[0xb75fed9a]
/usr/lib/libQtGui.so.4(_ZN5QIconC1ERK7QString+0x2e)[0xb793ba60]
/home/gyre/temp/06_filter_widget_added/bin/qcanalyzer[0x805ba16]
/home/gyre/temp/06_filter_widget_added/bin/qcanalyzer[0x8057a63]
/home/gyre/temp/06_filter_widget_added/bin/qcanalyzer(_ZNK18QAbstractItemModel5matchERK11QMod elIndexiRK8QVarianti6QFlagsIN2Qt9MatchFlagEE+0x4f3 )[0x80535c7]
/lib/libc.so.6(__libc_start_main+0xe0)[0xb72f8050]
/home/gyre/temp/06_filter_widget_added/bin/qcanalyzer(_ZNK6QFrame8sizeHintEv+0x8d)[0x8053421]
======= Memory map: ========
08048000-080b2000 r-xp 00000000 08:03 1934881 /home/gyre/temp/06_filter_widget_added/bin/qcanalyzer
080b2000-080b3000 rw-p 0006a000 08:03 1934881 /home/gyre/temp/0f54000 rw-p 00001000 08:03 3883263 /lib/libdl-2.6.1.so
b6f54000-b703c000 r-xp 00000000 08:03 5051900 /usr/lib/libX11.so.6.2.0
b703c000-b7040000 rw-p 000e8000 08:03 5051900 /usr/lib/libX11.so.6.2.0
b7040000-b704d000 r-xp 00000000 08:03 5049986 /usr/lib/libXext.so.6.4.0
b704d000-b704e000 rw-p 0000c000 08:03 5049986 /usr/lib/libXext.so.6.4.0
b704e000-b7071000 r-xp 00000000 08:03 5051365 /usr/lib/libfontconfig.so.1.2.0
b7071000-b7079000 rw-p 00023000 08:03 5051365 /usr/lib/libfontconfig.so.1.2.0
b7079000-b707a000 rw-p b7079000 00:00 0
b707a000-b70e5000 r-xp 00000000 08:03 1032250 /usr/lib/libfreetype.so.6.3.16
b70e5000-b70e9000 rw-p 0006a000 08:03 1032250 /usr/lib/libfreetype.so.6.3.16
b70e9000-b70eb000 r-xp 00000000 08:03 1032259 /usr/lib/libXinerama.so.1.0.0
b70eb000-b70ec000 rw-p 00001000 08:03 1032259 /usr/lib/libXinerama.so.1.0.0
b70ec000-b70f4000 r-xp 00000000 08:03 1032243 /usr/lib/libXcursor.so.1.0.2
b70f4000-b70f5000 rw-p 00007000 08:03 1032243 /usr/lib/libXcursor.so.1.0.2
b70f5000-b70f9000 r-xp 00000000 08:03 5051904 /usr/lib/libXfixes.so.3.1.0
b70f9000-b70fa000 rw-p 00003000 08:03 5051904 /usr/lib/libXfixes.so.3.1.0
[stack]

and so on

**wysota** · 10th December 2007, 16:14

It's not a memory leak. You must have made a mistake in your code...

Here is something that works for me:

Qt Code:

Switch view

#include <QApplication>
#include <QAbstractListModel>
#include <QListView>
#include <QList>
#include <QHash>
#include <QTimerEvent>
 
class Model : public QAbstractListModel {
public:
  Model() : QAbstractListModel() {m_tid = -1;}
  void add(int id){
    if(m_hash.contains(id)){
      int row = m_hash[id];
      m_data[row].count++;
      emit dataChanged(index(row), index(row));
    } else {
      int row = m_data.count();
      beginInsertRows(QModelIndex(), row, row);
      S s;
      s.id = id;
      s.count = 1;
      m_data.append(s);
      m_hash[id] = row;
      endInsertRows();
    }
  }
  int columnCount(const QModelIndex&) const { return 1; }
  int rowCount(const QModelIndex &) const { return m_data.count(); }
  QVariant data(const QModelIndex &index, int role=Qt::DisplayRole) const{
    if(role!=Qt::DisplayRole || !hasIndex(index.row(), index.column(), index.parent()))
      return QVariant();
    int row = index.row();
    return QString("%1: %2").arg(m_data[row].id).arg(m_data[row].count);
  }
  QModelIndex parent(const QModelIndex &) const { return QModelIndex(); }
  void start(){ m_tid = startTimer(100); }
protected:
  void timerEvent(QTimerEvent *e){
    if(e->timerId()==m_tid){
      int id = qrand() % 20;
      add(id);
    } else
      QAbstractListModel::timerEvent(e);
  }
private:
  struct S {
    int id;
    int count;
    S(){id=-1;count=1;}
  };
  QList<S> m_data;
  QHash<int, int> m_hash;
  int m_tid;
};
 
int main(int argc, char **argv){
  QApplication app(argc, argv);
  Model m;
  QListView lv;
  lv.setModel(&m);
  m.start();
  lv.show();
  return app.exec();
}

#include <QApplication>
#include <QAbstractListModel>
#include <QListView>
#include <QList>
#include <QHash>
#include <QTimerEvent>

class Model : public QAbstractListModel {
public:
  Model() : QAbstractListModel() {m_tid = -1;}
  void add(int id){
    if(m_hash.contains(id)){
      int row = m_hash[id];
      m_data[row].count++;
      emit dataChanged(index(row), index(row));
    } else {
      int row = m_data.count();
      beginInsertRows(QModelIndex(), row, row);
      S s;
      s.id = id;
      s.count = 1;
      m_data.append(s);
      m_hash[id] = row;
      endInsertRows();
    }
  }
  int columnCount(const QModelIndex&) const { return 1; }
  int rowCount(const QModelIndex &) const { return m_data.count(); }
  QVariant data(const QModelIndex &index, int role=Qt::DisplayRole) const{
    if(role!=Qt::DisplayRole || !hasIndex(index.row(), index.column(), index.parent()))
      return QVariant();
    int row = index.row();
    return QString("%1: %2").arg(m_data[row].id).arg(m_data[row].count);
  }
  QModelIndex parent(const QModelIndex &) const { return QModelIndex(); }
  void start(){ m_tid = startTimer(100); }
protected:
  void timerEvent(QTimerEvent *e){
    if(e->timerId()==m_tid){
      int id = qrand() % 20;
      add(id);
    } else
      QAbstractListModel::timerEvent(e);
  }
private:
  struct S {
    int id;
    int count;
    S(){id=-1;count=1;}
  };
  QList<S> m_data;
  QHash<int, int> m_hash;
  int m_tid;
};

int main(int argc, char **argv){
  QApplication app(argc, argv);
  Model m;
  QListView lv;
  lv.setModel(&m);
  m.start();
  lv.show();
  return app.exec();
}

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**gyre** · 10th December 2007, 16:27

I went through my code milion times

...
Thanks buddy...Ill take a look at yours and try to find a mistake

...

**gyre** · 10th December 2007, 17:40

so...I remade my codes...now they compile OK...and my app doesnt exit with the code as above...but the statistics dont get actualized ...even when I emit dataChanged() signal when the data get updated...but they still dont

...
I slowly but surely give up

...

Qt Code:

Switch view

int MsgStatsModel::rowCount(const QModelIndex &parent) const
{
	Q_UNUSED(parent);
	return idStatsList.count();
 
}
 
int MsgStatsModel::columnCount(const QModelIndex &parent) const
{
	Q_UNUSED(parent);
	return 2;
 
}
 
QVariant MsgStatsModel::headerData(int section, Qt::Orientation orientation, int role) const
{
	QVariant ret = QAbstractTableModel::headerData(section, orientation, role);
	if(orientation == Qt::Horizontal){
		if(role == Qt::DisplayRole){
			switch(section){
				case 0 :
					return tr("ID");
					break;
				case 1 :
					return tr("Count");
					break;
				case 2 :
					return tr("Comment");
					break;
				default :
					break;
			}
		}
	}
	return ret;
}
 
QVariant MsgStatsModel::data(const QModelIndex &index, int role) const
{
 
	QVariant ret;
 
	if(!index.isValid()){
		std::cout <<"Invalid Index of data provided!"<< std::endl;
		return ret;
	}
 
	int row = index.row();
	int col = index.column();
 
	if(row >= 0 && row < rowCount()) {
		if(role == Qt::DisplayRole) {
			switch(col) {
				case 0 :
					ret = idStatsList[row].id;
					break;
				case 1 :
					ret = idStatsList[row].count;
					break;
				case 2 :
					//ret = item.comments;
					ret=QVariant();
					break;
				default :
					break;
			}
		}
	}
	return ret;
}
 
//SLOT catching new arriving messages
void MsgStatsModel::updateStats(const QVcaCanMsg &canmsg)
{
	int id = canmsg.id();
 
	if(indexHash.contains(id)){
		int row = indexHash[id];
		idStatsList[row].count++;
		emit dataChanged(index(row, 0), index(row, 0));
	} else {
		int row = idStatsList.count();
		beginInsertRows(QModelIndex(), row, row);
		StatsItem item;
		item.id = id;
		item.count = 1;
		idStatsList.append(item);
		indexHash[id] = row;
		endInsertRows();
	}
}

int MsgStatsModel::rowCount(const QModelIndex &parent) const
{
	Q_UNUSED(parent);
	return idStatsList.count();

}

int MsgStatsModel::columnCount(const QModelIndex &parent) const
{
	Q_UNUSED(parent);
	return 2;

}

QVariant MsgStatsModel::headerData(int section, Qt::Orientation orientation, int role) const
{
	QVariant ret = QAbstractTableModel::headerData(section, orientation, role);
	if(orientation == Qt::Horizontal){
		if(role == Qt::DisplayRole){
			switch(section){
				case 0 :
					return tr("ID");
					break;
				case 1 :
					return tr("Count");
					break;
				case 2 :
					return tr("Comment");
					break;
				default :
					break;
			}
		}
	}
	return ret;
}

QVariant MsgStatsModel::data(const QModelIndex &index, int role) const
{

	QVariant ret;
		
	if(!index.isValid()){
		std::cout <<"Invalid Index of data provided!"<< std::endl;
		return ret;
	}
	
	int row = index.row();
	int col = index.column();
		
	if(row >= 0 && row < rowCount()) {
		if(role == Qt::DisplayRole) {
			switch(col) {
				case 0 :
					ret = idStatsList[row].id;
					break;
				case 1 :
					ret = idStatsList[row].count;
					break;
				case 2 :
					//ret = item.comments;
					ret=QVariant();
					break;
				default :
					break;
			}
		}
	}
	return ret;
}

//SLOT catching new arriving messages
void MsgStatsModel::updateStats(const QVcaCanMsg &canmsg)
{
	int id = canmsg.id();

	if(indexHash.contains(id)){
		int row = indexHash[id];
		idStatsList[row].count++;
		emit dataChanged(index(row, 0), index(row, 0));
	} else {
		int row = idStatsList.count();
		beginInsertRows(QModelIndex(), row, row);
		StatsItem item;
		item.id = id;
		item.count = 1;
		idStatsList.append(item);
		indexHash[id] = row;
		endInsertRows();
	}
}

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something is wrong...but cant figure out what...statistics get stored CORRECTLY...count is incremented nicely even for different ids...the problem is display in TableView...

**wysota** · 10th December 2007, 18:18

Qt Code:

Switch view

emit dataChanged(index(row, 0), index(row, 0));

emit dataChanged(index(row, 0), index(row, 0));

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If you have three columns, I suggest you emit it like:

Qt Code:

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emit dataChanged(index(row, 0), index(row, 2));

emit dataChanged(index(row, 0), index(row, 2));

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If you emit changes only in the first column, nothing gets updated, because your count is in the second column, so the correct version is:

Qt Code:

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emit dataChanged(index(row, 1), index(row, 1));

emit dataChanged(index(row, 1), index(row, 1));

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