unit QueueFrm;

interface

uses
  Winapi.Windows, Winapi.Messages,
  System.SysUtils, System.Variants, System.Classes, System.SyncObjs, System.Generics.Collections,
  Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls,
  Data.Consumer.Intf;

type
  TDataConsumerFrm = class(TForm, IDataConsumer)
    btnStart: TButton;
    mmoLog: TMemo;
    procedure btnStartClick(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    FQueue: TQueue<Integer>;
    procedure ShowData;
    procedure LogToMemo(const ADataStr: string);
  public
    procedure GetDataOnIdle(Sender: TObject; var Done: Boolean);
    procedure Notify(const AData: Pointer; const ADataCount: Cardinal); stdcall;
  end;

var
  DataConsumerFrm: TDataConsumerFrm;

procedure SubscribeConsumer(const ADataConsumer: IDataConsumer); stdcall; external 'QueueDLL.dll';

implementation

{$R *.dfm}

{ TDataConsumerFrm }

procedure TDataConsumerFrm.btnStartClick(Sender: TObject);
begin
  SubscribeConsumer(Self);
end;

procedure TDataConsumerFrm.FormCreate(Sender: TObject);
begin
  FQueue := TQueue<Integer>.Create;
  TThread.NameThreadForDebugging('VCL-MainThread', MainThreadID);
  Application.OnIdle := GetDataOnIdle;
end;

procedure TDataConsumerFrm.FormDestroy(Sender: TObject);
begin
  SubscribeConsumer(nil);
  FQueue.Free;
end;

procedure TDataConsumerFrm.GetDataOnIdle(Sender: TObject; var Done: Boolean);
var
  LValue: Integer;
begin
  ShowData;
end;

procedure TDataConsumerFrm.Notify(const AData: Pointer; const ADataCount: Cardinal);
var
  LDataPtr: PInteger;
  LValue: Integer;
  I: Integer;
begin
  System.TMonitor.Enter(FQueue);
  try
    if Assigned(AData) and (ADataCount > 0) then
    begin
      LDataPtr := AData;
      for I := 0 to ADataCount - 1 do
      begin
        LValue := PInteger(LDataPtr)^;
        FQueue.Enqueue(LValue);
        Inc(LDataPtr);
      end;
    end;
  finally
    System.TMonitor.Exit(FQueue);
  end;
end;

procedure TDataConsumerFrm.ShowData;
var
  LValue: Integer;
  LDataStr: string;
begin
  System.TMonitor.Enter(FQueue);
  try
    while FQueue.Count > 0 do
    begin
      LValue := FQueue.Dequeue;
      LDataStr := LValue.ToString;
      LogToMemo(LDataStr);
    end;
  finally
    System.TMonitor.Exit(FQueue);
  end;
end;

procedure TDataConsumerFrm.LogToMemo(const ADataStr: string);
begin
  mmoLog.Lines.Add(ADataStr);

  if mmoLog.Lines.Count > 5000 then
  begin
    mmoLog.Lines.Clear;
  end;
end;

end.