//////////////////////////////////////////////////////////////////////
//                                                                  //
// tools.pas: Plugin management                                     //
//                                                                  //
// The contents of this file are subject to the Bottled Light       //
// Public License Version 1.0 (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.bottledlight.com/BLPL/         //
//                                                                  //
// Software distributed under the License is distributed on an      //
// "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or   //
// implied. See the License for the specific language governing     //
// rights and limitations under the License.                        //
//                                                                  //
// The Original Code is the Mappy VM User Interface, released       //
// April 1st, 2003. The Initial Developer of the Original Code is   //
// Bottled Light, Inc. Portions created by Bottled Light, Inc. are  //
// Copyright (C) 2001-2003 Bottled Light, Inc. All Rights Reserved. //
//                                                                  //
// Author(s):                                                       //
//   Michael Noland (joat), michael@bottledlight.com                //
//                                                                  //
// Changelog:                                                       //
//   1.0: First public release (April 1st, 2003)                    //
//                                                                  //
// Notes:                                                           //
//   Plugin support is completly untested.                          //
//                                                                  //
//////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////
unit tools; //////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////
interface ////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

uses
  Windows, Classes, SysUtils, Contnrs, nexus, AddressSpace;

//////////////////////////////////////////////////////////////////////

type
  TPlugin = class
  public
    header: PvmPluginHeader;
    constructor Create(filename: PChar);
    destructor Destroy; override;
    procedure Trigger;
  private
    DLLHandle: uint32;
    loaded: boolean;
  end;

//////////////////////////////////////////////////////////////////////

var
  plugins: TObjectList;

//////////////////////////////////////////////////////////////////////

procedure EnumeratePlugins;
procedure TriggerPlugin(index: integer);

//////////////////////////////////////////////////////////////////////
implementation ///////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

procedure EnumeratePlugins;
var
  f: TSearchRec;
  p: TPlugin;
begin
  if FindFirst(ExtractFilePath(ParamStr(0)) + 'plugins/*.dll', faReadOnly + faHidden + faArchive, f) = 0 then
    repeat
      // Try to load a DLL as a plugin
      p := TPlugin.Create(PChar(f.name));
      if p.loaded then plugins.Add(p) else p.Free;
    until FindNext(f) <> 0;
  FindClose(f);
end;

//////////////////////////////////////////////////////////////////////

procedure TriggerPlugin(index: integer);
begin
  if (index >= 0) and (index < plugins.Count) then
    TPlugin(plugins[index]).Trigger;
end;

//////////////////////////////////////////////////////////////////////
// TPlugin ///////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////

constructor TPlugin.Create(filename: PChar);
var
  GetHeader: function: PvmPluginHeader; cdecl;
begin
  loaded := false;
  DLLHandle := LoadLibrary(filename);
  if DLLHandle >= 32 then begin
    GetHeader := GetProcAddress(DLLHandle, 'GetHeader');
    if @GetHeader <> nil then begin
      Header := GetHeader;
      loaded := true;
    end;
  end
end;

//////////////////////////////////////////////////////////////////////

destructor TPlugin.Destroy;
begin
  if loaded then FreeLibrary(DLLHandle);
  inherited;
end;

//////////////////////////////////////////////////////////////////////

procedure TPlugin.Trigger;
begin
  with header^ do
    if triggerCaption <> nil then begin
      vmLockMemory(mem);
      Trigger;
      vmUnlockMemory(mem);
    end;
end;

//////////////////////////////////////////////////////////////////////

initialization
  plugins := TObjectList.Create;
finalization
  plugins.Free;
end.

//////////////////////////////////////////////////////////////////////