Слежение за каталогом

unit FileMonitorThreadUnit;
 
interface
 
uses
  Classes, Windows, SysUtils;
 
type
  TFileNotifyInformation = packed record
    NextEntryOffset: DWORD;
    Action: DWORD;
    FileNameLength: DWORD;
    FileName: WideChar;
  end;
 
  PFileNotifyInformation = ^TFileNotifyInformation;
 
  TFileEvent = procedure (const FileName: string) of object;
 
  // ïîòîê äëÿ ñëåæåíèÿ çà ïîÿâëåíèåì ôàéëîâ â äèðåêòîðèè
  TFileMonitorThread = class(TThread)
  private
    // äèðåêòîðèÿ äëÿ ñëåæåíèÿ
    FMonitoringDir: string;
    // òåêóùèé îáðàáàòûâàåìûé ôàéë
    FCurrFileName: string;
 
    FOnAddFile: TFileEvent;
    FOnRemoveFile: TFileEvent;
    FOnError: TNotifyEvent;
 
  protected
    // ôàéë ïðèíÿò
    procedure DoAddFile;
    // ôàéë óäàë¸í
    procedure DoRemoveFile;
    // ôàéë ìîäèôèöèðîâàí
    procedure DoModifyFile;
    // îøèáêà!
    procedure DoError;
    procedure Execute; override;
  public
    constructor Create(const MonitoringDir: string; CreateSuspended: Boolean;
      WatchSubTree: Boolean = False);
    property OnAddFile: TFileEvent read FOnAddFile write FOnAddFile;
    property OnRemoveFile: TFileEvent read FOnRemoveFile write FOnRemoveFile;
    property OnError: TNotifyEvent read FOnError write FOnError;
  end;
 
implementation
 
uses
  FormMainUnit;
 
{ TFileMonitorThread }
 
constructor TFileMonitorThread.Create(const MonitoringDir: string;
  CreateSuspended: Boolean; WatchSubTree: Boolean = False);
begin
  inherited Create(True);
  FreeOnTerminate := True;
  FMonitoringDir := MonitoringDir;
  if not CreateSuspended then Resume;
end;
 
procedure TFileMonitorThread.Execute;
var
  DirHandle: Cardinal;
  Buffer: Pointer;
  BytesReturn: Cardinal;
  LocalFileName: PWideChar;
  CurrPtr: PFileNotifyInformation;
 
  DirEvent: Cardinal;
  Ovr: OVERLAPPED;
  Events: array [0..1] of Cardinal;
  WaitResult: Cardinal;
const
  FILE_LIST_DIRECTORY = $01;
  BUF_SIZE = (SizeOf(TFileNotifyInformation) + MAX_PATH * 2) * 32;
 
begin
 
  DirHandle := CreateFile(PChar(FMonitoringDir), FILE_LIST_DIRECTORY,
    FILE_SHARE_READ or FILE_SHARE_DELETE or FILE_SHARE_WRITE, nil, OPEN_EXISTING,
    FILE_FLAG_BACKUP_SEMANTICS or FILE_FLAG_OVERLAPPED, 0);
 
  if DirHandle = INVALID_HANDLE_VALUE then
  begin
    FormMain.Log.Write('ÎØÈÁÊÀ! Íå óäàëîñü ïîëó÷èòü äîñòóï ê ïàïêå "' +
      FMonitoringDir + '"');
    Exit;
  end;
 
  // ñîçäà¸ì îáúåêò ñèíõðîíèçàöèè äëÿ ðàáîòû ô-èè ReadDirectoryChangesW
  DirEvent := CreateEvent(nil, True, False, nil);
 
  GetMem(Buffer, BUF_SIZE);
 
  while not Terminated do
  begin
    ZeroMemory(Buffer, BUF_SIZE);
    ZeroMemory(@Ovr, SizeOf(Ovr));
 
    // ïåðåäà¸ì event â ñòðóêòóðó
    Ovr.hEvent := DirEvent;
 
    // âåøàåì îáðàáîòêó òîëüêî íà èçìåíåíèå ôàéëà
    if ReadDirectoryChangesW(DirHandle, Buffer, BUF_SIZE, True,
         FILE_NOTIFY_CHANGE_FILE_NAME or FILE_NOTIFY_CHANGE_SIZE,
         @BytesReturn,
         @Ovr, nil) then
{
    if ReadDirectoryChangesW(DirHandle, Buffer, BUF_SIZE, False,
      FILE_NOTIFY_CHANGE_FILE_NAME, @BytesReturn, nil, nil) then
      }
 
    Events[0] := FormMain.FTerminateEvent;
    Events[1] := DirEvent;
    WaitResult := WaitForMultipleObjects(2, @Events, False, 1000);
 
    case WaitResult of
      WAIT_OBJECT_0: Terminate;
      WAIT_OBJECT_0 + 1:
      begin
        CurrPtr := Buffer;
 
        repeat
          // ïåðåìåùàåì óêàçàòåëü íà ñëåäóþùóþ çàïèñü â ñòðóêòóðå PFileNotifyInformation
          Inc(Cardinal(CurrPtr), CurrPtr^.NextEntryOffset);
 
          // ïîäãîòàâëèâàåì ïåðåìåííóþ FileName äëÿ ïðè¸ìà ñòðîêè
          GetMem(LocalFileName, CurrPtr^.FileNameLength + 2);
          ZeroMemory(LocalFileName, CurrPtr^.FileNameLength + 2);
 
          // êîïèðóåì
          LstrcpynW(LocalFileName, @CurrPtr^.FileName, CurrPtr^.FileNameLength div 2 + 2);
 
          // êîíâåðòèðóåì è çàïîìèíàåì äëÿ îáðàáîòêè èìÿ ôàéëà
          
          FCurrFileName := LocalFileName;
          case CurrPtr.Action of
            FILE_ACTION_ADDED: Synchronize(DoAddFile);
            FILE_ACTION_REMOVED: Synchronize(DoRemoveFile);
            FILE_ACTION_MODIFIED: Synchronize(DoModifyFile);
          end;
          FreeMem(LocalFileName);
 
        until CurrPtr^.NextEntryOffset = 0;
      end;
    end;
  end;
 
  FreeMem(Buffer);
  CloseHandle(DirHandle);
end;
 
procedure TFileMonitorThread.DoAddFile;
begin
  if Assigned(FOnAddFile) then
    FOnAddFile(FMonitoringDir + FCurrFileName);
end;
 
procedure TFileMonitorThread.DoRemoveFile;
begin
  if Assigned(FOnRemoveFile) then
    FOnRemoveFile(FMonitoringDir + FCurrFileName);
end;
 
procedure TFileMonitorThread.DoModifyFile;
begin
end;
 
procedure TFileMonitorThread.DoError;
begin
  if Assigned(FOnError) then FOnError(nil);
end;
 
end.