{-----------------------------------------------------------------------------
The contents of this file are subject to the Mozilla Public License
Version 1.1 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.mozilla.org/MPL/MPL-1.1.html

Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either expressed or implied. See the License for
the specific language governing rights and limitations under the License.

The Original Code is: JvCommStatus.PAS, released on 2001-02-28.

The Initial Developer of the Original Code is Sébastien Buysse [sbuysse att buypin dott com]
Portions created by Sébastien Buysse are Copyright (C) 2001 Sébastien Buysse.
All Rights Reserved.

Contributor(s): Michael Beck [mbeck att bigfoot dott com].

You may retrieve the latest version of this file at the Project JEDI's JVCL home page,
located at http://jvcl.sourceforge.net

Known Issues:
-----------------------------------------------------------------------------}
// $Id: JvCommStatus.pas 10612 2006-05-19 19:04:09Z jfudickar $

unit JvCommStatus;

{$I jvcl.inc}
{$I windowsonly.inc}

interface

uses
  {$IFDEF UNITVERSIONING}
  JclUnitVersioning,
  {$ENDIF UNITVERSIONING}
  Windows, Classes,
  JvComponentBase;

type
  TJvCommPort = 0..8; // ToDo: Port number might be up to 32 !

  TJvCommWatcher = class(TThread)
  private
    FHandle: THandle;
    FStat: Cardinal;
    FOnChange: TNotifyEvent;
    procedure Changed;
  protected
    procedure Execute; override;
  end;

  TJvCommStatus = class(TJvComponent)
  private
    FClearToSend: Boolean;
    FDataSetReady: Boolean;
    FRing: Boolean;
    FReceiveLine: Boolean;
    FHandle: THandle;
    FWatcher: TJvCommWatcher;
    FDummy: Boolean;
    FPendingEvent, FPendingResume: Boolean;  // Arioch
    FComm: TJvCommPort;
    FOnChanged: TNotifyEvent;
    procedure SetComm(const Value: TJvCommPort);
    procedure WatcherThreadChanged(Sender: TObject); //Arioch
    procedure WatcherThreadTerminated(Sender: TObject); //Arioch
    procedure UpdateStates(State: Cardinal);
  protected
    procedure Loaded; override; //Arioch
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    { Do not store dummies }
    property ClearToSend: Boolean read FClearToSend write FDummy stored False;
    property DataSetReady: Boolean read FDataSetReady write FDummy stored False;
    property Ring: Boolean read FRing write FDummy stored False;
    property ReceiveLine: Boolean read FReceiveLine write FDummy stored False;
    property Comm: TJvCommPort read FComm write SetComm default 0;
    property OnChanged: TNotifyEvent read FOnChanged write FOnChanged;
  end;

{$IFDEF UNITVERSIONING}
const
  UnitVersioning: TUnitVersionInfo = (
    RCSfile: '$URL: https://svn.sourceforge.net:443/svnroot/jvcl/trunk/jvcl/run/JvCommStatus.pas $';
    Revision: '$Revision: 10612 $';
    Date: '$Date: 2006-05-19 23:04:09 +0400 (Пт, 19 май 2006) $';
    LogPath: 'JVCL\run'
  );
{$ENDIF UNITVERSIONING}

implementation

uses
  SysUtils;

//=== { TJvCommStatus } ======================================================

constructor TJvCommStatus.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FComm := 0;
  FHandle := 0;
  FPendingEvent := false; FPendingResume := false;

  if not (csDesigning in ComponentState) then
  begin
    FWatcher := TJvCommWatcher.Create(True);
    FWatcher.FHandle := FHandle;
    FWatcher.FStat := 0;
    FWatcher.FreeOnTerminate := True;
    FWatcher.OnTerminate := WatcherThreadTerminated; //Arioch
    FWatcher.FOnChange := WatcherThreadChanged;  // Arioch
  end
  else
    FWatcher := nil;

  UpdateStates(0); //Arioch
end;

destructor TJvCommStatus.Destroy;
begin
  if FWatcher <> nil then
  begin   //Arioch
    FWatcher.OnTerminate := nil; // we do not want events be accidentally called after Sleep(50)
    FWatcher.FOnChange := nil;   // when the JvCommStatus will turn into dead pointer !!!
    FWatcher.Terminate;
    FWatcher := nil;
  end;
  if FHandle <> 0 then
    CloseHandle(FHandle);
  inherited Destroy;
end;

procedure TJvCommStatus.UpdateStates(State: Cardinal);
begin
  FClearToSend :=  (State and MS_CTS_ON) <> 0;
  FDataSetReady := (State and MS_DSR_ON) <> 0;
  FRing :=         (State and MS_RING_ON) <> 0;
  FReceiveLine :=  (State and MS_RLSD_ON) <> 0;
end;

procedure TJvCommStatus.WatcherThreadChanged(Sender: TObject);
begin
  if (FWatcher <> nil) and (FHandle <> 0) then
    UpdateStates(FWatcher.FStat)
  else
    UpdateStates(0);

  if not (csDesigning in ComponentState) then
     if not (csLoading in ComponentState) // Arioch
        then begin
               if Assigned(FOnChanged) then FOnChanged(Self)
             end  
        else FPendingEvent := true;
end;

procedure TJvCommStatus.WatcherThreadTerminated(Sender: TObject);
begin
  FWatcher := nil;  // FreeOnTerminate is set
end;

procedure TJvCommStatus.SetComm(const Value: TJvCommPort);
var
  Stat: Cardinal;
  CommName: string;
begin
  if FWatcher <> nil then
     FWatcher.FHandle := 0; // do not suspend
  if FHandle <> 0 then
  begin // <-- ****
    CloseHandle(FHandle);
    FHandle := 0;
  end;  // <-- ****
  FComm := Value;
  // (rom) simplified through better TJvCommPort
  Stat := 0; // Arioch
  if FComm <> 0 then
  begin
    CommName := 'COM' + IntToStr(FComm);
    FHandle := CreateFile(PChar(CommName), 0, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0);
    if FHandle = INVALID_HANDLE_VALUE
       then
         FHandle := 0
       else if not GetCommModemStatus(FHandle, Stat)
               then Stat := 0; // i am not 100% sure Windows would never change var on error
  end;

  if FWatcher <> nil then
  begin
    FWatcher.FHandle := FHandle;
    FWatcher.FStat := Stat; // <-- *****
    if FHandle <> 0 then
       if not (csLoading in ComponentState) // Arioch 
          then FWatcher.Resume
          else FPendingResume := True; // Arioch
//    else
//      FWatcher.Suspend;    // Arioch: Already suspended before
  end;
  
  WatcherThreadChanged(Self);
end;

procedure TJvCommStatus.Loaded; // Arioch
begin
  inherited;
  if FPendingEvent then begin
     FPendingEvent := False;
     WatcherThreadChanged(Self);
  end;
  if FPendingResume then begin
     FPendingResume := false;
     if Assigned (FWatcher) then FWatcher.resume;
  end;
end;



//=== { TJvCommWatcher } =====================================================

procedure TJvCommWatcher.Changed;
begin
  FOnChange(nil);
end;

procedure TJvCommWatcher.Execute;
var
  Mask: Cardinal;
begin
  // (rom) secure thread against exceptions
  try
    while not Terminated do
    begin
      if FHandle <> 0 then
      begin
        GetCommModemStatus(FHandle, Mask);
        if Mask <> FStat then
        begin
          FStat := Mask;
          Synchronize(Changed);
        end;
      Sleep(50);
      end
      else Suspend;
    end;
  except
  end;
end;

{$IFDEF UNITVERSIONING}
initialization
  RegisterUnitVersion(HInstance, UnitVersioning);

finalization
  UnregisterUnitVersion(HInstance);
{$ENDIF UNITVERSIONING}

end.