Script to launch given shell command on directory/file change

beholder.cpp

/**
 * Beholder
 * 
 * @author Jiri "NoxArt" Petruzelka | www.noxart.cz | [email protected]
 * @author Microsoft
 * 
 * @filesource
 * 
 * @link http://msdn.microsoft.com/en-us/library/windows/desktop/aa365261(v=vs.85).aspx
 */
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>
#include <string>

using std::string;

string onChangeHandler;
bool debug = false;

void DirectoryChanged(LPTSTR);
void TreeChanged(LPTSTR);
void WatchDirectory(LPTSTR);

int _tmain(int argc, TCHAR *argv[])
{
    if(argc != 3 && argc != 4)
    {
        _tprintf(TEXT("Usage: %s <dir> <runOnChange> [debug]\n"), argv[0]);
        return 0;
    }
	
	debug = (argc == 4);
	if( debug )
		_tprintf(TEXT("[Beholder: running in DEBUG mode]"));
	
	onChangeHandler = string(argv[2]);
    WatchDirectory(argv[1]);
	
	return 0;
}

void WatchDirectory(LPTSTR lpDir)
{
   DWORD dwWaitStatus; 
   HANDLE dwChangeHandles[2]; 
   TCHAR lpDrive[4];
   TCHAR lpFile[_MAX_FNAME];
   TCHAR lpExt[_MAX_EXT];

   _splitpath(lpDir, lpDrive, NULL, lpFile, lpExt);

   lpDrive[2] = (TCHAR)'\\';
   lpDrive[3] = (TCHAR)'\0';
 
// Watch the directory for file creation and deletion. 
 
   dwChangeHandles[0] = FindFirstChangeNotification( 
      lpDir,                         // directory to watch 
      TRUE,                         // do watch subtree 
      FILE_NOTIFY_CHANGE_FILE_NAME); // watch file name changes 
 
   if (dwChangeHandles[0] == INVALID_HANDLE_VALUE) 
   {
     printf("\n ERROR: FindFirstChangeNotification function failed.\n");
     ExitProcess(GetLastError()); 
   }
 
// Watch the subtree for directory creation and deletion. 
 
   dwChangeHandles[1] = FindFirstChangeNotification( 
      lpDrive,                       // directory to watch 
      TRUE,                          // watch the subtree 
      FILE_NOTIFY_CHANGE_DIR_NAME);  // watch dir name changes 
 
   if (dwChangeHandles[1] == INVALID_HANDLE_VALUE) 
   {
     printf("\n ERROR: FindFirstChangeNotification function failed.\n");
     ExitProcess(GetLastError()); 
   }
 

// Make a final validation check on our handles.

   if ((dwChangeHandles[0] == NULL) || (dwChangeHandles[1] == NULL))
   {
     printf("\n ERROR: Unexpected NULL from FindFirstChangeNotification.\n");
     ExitProcess(GetLastError()); 
   }

// Change notification is set. Now wait on both notification 
// handles and refresh accordingly. 
 
   while (TRUE) 
   { 
   // Wait for notification.
	   if(debug)
      printf("\nWaiting for notification...\n");

      dwWaitStatus = WaitForMultipleObjects(2, dwChangeHandles, 
         FALSE, INFINITE); 
 
      switch (dwWaitStatus) 
      { 
         case WAIT_OBJECT_0: 
 
         // A file was created, renamed, or deleted in the directory.
         // Refresh this directory and restart the notification.
 
             DirectoryChanged(lpDir); 
             if ( FindNextChangeNotification(dwChangeHandles[0]) == FALSE )
             {
               printf("\n ERROR: FindNextChangeNotification function failed.\n");
               ExitProcess(GetLastError()); 
             }
             break; 
 
         case WAIT_OBJECT_0 + 1: 
 
         // A directory was created, renamed, or deleted.
         // Refresh the tree and restart the notification.
 
             TreeChanged(lpDrive); 
             if (FindNextChangeNotification(dwChangeHandles[1]) == FALSE )
             {
               printf("\n ERROR: FindNextChangeNotification function failed.\n");
               ExitProcess(GetLastError()); 
             }
             break; 
 
         case WAIT_TIMEOUT:

         // A timeout occurred, this would happen if some value other 
         // than INFINITE is used in the Wait call and no changes occur.
         // In a single-threaded environment you might not want an
         // INFINITE wait.
 
            printf("No changes in the timeout period.\n");
            break;

         default: 
            printf("ERROR: Unhandled dwWaitStatus.\n");
            ExitProcess(GetLastError());
            break;
      }
   }
}

void DirectoryChanged(LPTSTR lpDir)
{
	if( debug )
		_tprintf(TEXT("Directory (%s) changed.\n"), lpDir);
	else
		system(onChangeHandler.c_str());
}

void TreeChanged(LPTSTR lpDrive)
{
	if( debug )
		_tprintf(TEXT("Directory tree (%s) changed.\n"), lpDrive);
	else
		system(onChangeHandler.c_str());
}