内存泄漏，滥用线程？

Question

Im trying to use the threads for the first time, but cant tell why am i getting memory leak, cause of misuse of the thread, or cause im that stupid and forgot to free something, but at this point, i cant tell, which one (or both) is it.

This is the procedure that is being called on click

procedure TmainForm.scrollFrameClick(item:TEquipmentItem; itemFrame:TitemFrame);
begin
item.fullImage:=itemFrame.itemImage.Picture.Graphic;
setCurrentSearchItem(item);
end;

Procedure that calling thread

procedure TmainForm.setCurrentSearchItem(item:TEquipmentItem);
begin

if not(assigned(searchResultTable)) then
  searchResultTable:=TItemHtmlTable.Create
else
  begin
    freeandnil(searchResultTable);
    searchResultTable:=TItemHtmlTable.Create;
  end;

if getDomTh<>nil then
  if getDomTh.Finished then
    begin
      getDomTh.Terminate;
      getDomTh.WaitFor;
      FreeAndNil(getDomTh);
    end
  else
    begin
      getDomTh.WaitFor;
      getDomTh.Terminate;
      FreeAndNil(getDomTh);
    end;

getDomTh:=TCreateDomThread.Create(false,'http://www.example.com/ru/items/'+inttostr(item.ID),searchResultTable.DomTree);

currentItemImage.Picture.Graphic:=item.fullImage;
itemNameLab.Caption:=item.ItemName;
itemTypeLab.Caption:=item.ItemTypeName;
itemSubtypeLab.Caption:=item.ItemSubtypeName;

/////////////////
// At this point i would call a thread and use the result from the "searchResultTable"
/////////////////

if getDomTh<>nil then
  if getDomTh.Finished then
    freeandnil(searchResultTable)
  else
    begin
      getDomTh.WaitFor;
      getDomTh.Terminate;
      FreeAndNil(getDomTh);
      freeandnil(searchResultTable);
    end;
end;

This is the thread unit

unit threadUnit;

interface

uses System.Classes,System.SysUtils, parser;

type
  TCreateDomThread = class(TThread)
  private
    pDomTree:TDomTree;
    pUrl:string;
  public
    property tDomTree:TDomTree read pDomTree write pDomTree;
    property tUrl:string read pUrl write pUrl;
    constructor Create(suspended:boolean; Url:string; DomTree:TDomTree);
    procedure Execute; override;
  end;

implementation

uses main;


constructor TCreateDomThread.Create(suspended:boolean; Url:string; DomTree:TDomTree);
begin
  tDomTree:=DomTree;
  tUrl:=Url;
  inherited Create(suspended);
end;

procedure TCreateDomThread.Execute;
begin
    if Terminated then Exit;
    mainForm.getDomTree(tUrl, tDomTree);
end;
end.

DomTree retrieval

 procedure TmainForm.getDomTree(url:string; outputDomTree:TDomTree);
    var
      HtmlTxt: string;
    begin
      try
        HtmlTxt := IdHTTP1.Get(url);
        if not outputDomTree.RootNode.RunParse(HtmlTxt) then
          TThread.Queue(nil,procedure begin showmessage('Can'#39'tParse HTML!') end);
      except
        on E: Exception do
          TThread.Queue(nil,procedure begin ShowMessage(E.ClassName + ' : ' + E.Message); end);
      end;
    end;

If you call for the click a couple of times, taskmanager shows that committed memory is always increasing. I had no luck with debugging that, any advise would be much appreciated.

EDIT:

So there is a bunch of TDomTree which are not being free, but i couldnt understand, from where, cause thread is destroyed as expected

Delphi memory manager screenshot

EDIT 2: Found the error.

Answer 1

So i found the issue. StringList from the TDomTree was referenced in thread that updated the ui. So therefore, when worker thread tried to destroy the searchResultTable , its TDomTree 's StringList could not be terminated, creating exception, so whole TDomTree was not terminating.