Hi,

I'm finishing to develop an application. Everything works fine. Yesterday I made some tests and I noticed that I have a huge memory leak when I try to load new data.

I load 6000 lines of data that I transfer in TFPObjectList. I first thought that the problem came from the list. I removed the list code and the problem doesn't disappear. So, for me, the problem come from the XML reading procedure. I try to search in the wiki and I didn't found thing that help me. I sure that the method I use to read the XML is not right one.

Somebody can help me to correct my code?

The method without TFPObjectList code is below. Before reading the file the program use 16Mo of memory. After the execution of the 'LoadCGX' procedure the program use 204Mo :( .

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procedure TCGData.LoadCGX(s:String);
var
  xdoc: TXMLDocument;                         // variable to document
  RootNode,
  node, node1, TrackpointNode : TDOMNode;    // variable to nodes
  i, j, err : Integer;
  tmpCourseName : string;
  tmpDescription : string;
  tmps, tmps1 : string;
  tmpTotalDistance,td : Double;
  tmpVersion : String;
  tmpTotalTimeSecond : integer;
  ts : String;
Begin
  DateSeparator:='/';
  ShortDateFormat:='d/m/y';
  //-- Open the XML file --
  ReadXMLFile(xDoc, s);
  //-- Search the <CourseGenerator> node --
  RootNode := xDoc.FindNode('CourseGenerator');
  if RootNode=NIL then exit; //Not found exit
  For i:=0 to (RootNode.ChildNodes.Count - 1) do begin
    Node:=RootNode.ChildNodes.Item[i];
    tmps:=Node.NodeName;
    if tmps='Version' then begin
      //-- <Version> node --
      tmpVersion:= Node.TextContent;
      //Todo: test!
    end
    else if tmps='TotalDistance' then begin
      //-- <TotalDistance> node --
      Val(Node.TextContent,tmpTotalDistance,err);
      if err0 then exit;
    end
    else if tmps='TotalTimeSecond' then begin
      //-- <TotalTimeSecond> node --
      Val(Node.TextContent,tmpTotalTimeSecond,err);
      if err0 then exit;
    end
    else if tmps='CourseName' then begin
      //-- <CourseName> node --
      tmpCourseName:= Node.TextContent;
    end
    else if tmps='Description' then begin
      //-- <Description> node --
      tmpDescription:= Node.TextContent;
    end
    else if tmps='Trackpoint' then begin
      //-- <Trackpoint> node --
      TrackpointNode := Node;
      //-- Scan level "trackpoint" --
      for j := 0 to (TrackpointNode.ChildNodes.Count - 1) do begin
        Node1:=TrackpointNode.ChildNodes.Item[j];
        tmps1:=Node1.NodeName;
        if tmps1 = 'LatitudeDegrees' then begin
          //<LatitudeDegrees>123.456</LatitudeDegrees>
          val(Node1.TextContent,td,err);
          if err0 then begin
            td:=0;
                //Error
          end;
        end
        else if tmps1 = 'LongitudeDegrees' then begin
          //<LongitudeDegrees>123.456</LongitudeDegrees>
          val(Node1.TextContent,td,err);
          if err0 then begin
            td:=0;
                //Error
          end;
        end
        else if tmps1 = 'AltitudeMeters' then begin
          //<AltitudeMeters>123.456</AltitudeMeters>
          val(Node1.TextContent,td,err);
          if err0 then begin
            td:=0;
                //Error
          end;
        end;
      end; //For j
      //-- Store data --
      //List.Add(TmpData);
    end;
  end; //For i
  RootNode.free;
  xDoc.Free;
End;

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Thanks for your help.

Regards,

Pierre Delore wrote

... I try to search in the wiki and I didn't found thing that help me.

Since you did not specify your compiler version, I guess it's something pre-2.4.0. See this link:
http://wiki.freepascal.org/User_Changes_2.4.0#dom_unit:_memory_management_for_node_lists

Either upgrade to 2.4.0, or add a matching call of Free for each call of ChildNodes. The best solution, however, is to change the code to use FirstChild/NextSibling properties instead of ChildNodes, because FirstChild/NextSibling are faster and don't create any intermediate objects.

Regards,
Sergei

Thanks Sergei for your answer.

I Forgot to indicate that I use the last stable version of lazarus (0.9.28.2).

I will try to modify my code to use FirstChild/NextSibling.

Regards,

FirstChild/NextSibling fix my problem. Thanks.

Regards,

Besides what you corrected, the various 'exit' statement in your code will leave an xdoc unfreed.

Pierre Delore wrote

Hi, I'm finishing to develop an application. Everything works fine.

Yesterday I made some tests and I noticed that I have a huge memory leak when I try to load new data.

I load 6000 lines of data that I transfer in TFPObjectList. I first

thought that the problem came from the list. I removed the list code and the problem doesn't disappear. So, for me, the problem come from the XML reading procedure. I try to search in the wiki and I didn't found thing that help me. I sure that the method I use to read the XML is not right one.

the program use 16Mo of memory. After the execution of the 'LoadCGX' procedure the program use 204Mo :( .

>

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Hi Yves,

Thanks for your remark. I will modify the code.

Regards,