C++ ReadDirectoryChangesW函数代码示例

BOOL CDirWatcher::StartWatch(HWND hNotifyWnd, LPCTSTR lpszPath)
{
	m_hNotifyWnd = hNotifyWnd;
	m_strPath = lpszPath;

	m_hFileHandle = CreateFile(m_strPath, 
		FILE_LIST_DIRECTORY,
		FILE_SHARE_DELETE|FILE_SHARE_READ|FILE_SHARE_WRITE,
		NULL,
		OPEN_EXISTING,
		FILE_FLAG_BACKUP_SEMANTICS|FILE_FLAG_OVERLAPPED,
		NULL); 
	if (m_hFileHandle == INVALID_HANDLE_VALUE)
		return FALSE;

	m_hCompPort = CreateIoCompletionPort(m_hFileHandle, m_hCompPort, DWORD(this), 0);

	memset(&m_overlapped, 0, sizeof(OVERLAPPED));
	ReadDirectoryChangesW(m_hFileHandle, m_lpBuffer, 4096,
			FALSE, FILE_NOTIFY_CHANGE_FILE_NAME, &m_dwSize, &m_overlapped, NULL);
	
	m_hThread = CreateThread(NULL, 0, _WatchProc, (void*)this, 0, &m_dwThreadID);

	return TRUE;
}

static BOOL
register_monitoring_entry(WDM_PEntry entry)
{
    BOOL success;
    DWORD bytes;
    bytes = 0; // Not used because the process callback gets passed the written bytes

    success = ReadDirectoryChangesW(
        entry->dir_handle,                  // handle to directory
        entry->buffer,                      // read results buffer
        WDM_BUFFER_SIZE,                    // length of buffer
        entry->user_data->watch_childeren,  // monitoring option
        entry->user_data->flags,            // filter conditions
        &bytes,                             // bytes returned
        &entry->event_container,            // overlapped buffer
        &handle_entry_change                // process callback
    );

    if ( ! success ) {
        WDM_DEBUG("ReadDirectoryChangesW failed with error (%d): %s", GetLastError(), rb_w32_strerror(GetLastError()));
        return FALSE;
    }

    return TRUE;
}

void resman_check_watch(struct resman *rman)
{
    struct watch_dir *wdir;
    unsigned int idx;

    unsigned int num_handles = dynarr_size(rman->watch_handles);
    if(!num_handles) {
        return;
    }

    idx = WaitForMultipleObjectsEx(num_handles, rman->watch_handles, FALSE, 0, TRUE);
    if(idx == WAIT_FAILED) {
        unsigned int err = GetLastError();
        fprintf(stderr, "failed to check for file modification: %u\n", err);
        return;
    }
    if(idx >= WAIT_OBJECT_0 && idx < WAIT_OBJECT_0 + num_handles) {
        if(!(wdir = rb_find(rman->wdirbyev, rman->watch_handles[idx]))) {
            fprintf(stderr, "got change handle, but failed to find corresponding watch_dir!\n");
            return;
        }

        handle_event(rman, rman->watch_handles[idx], wdir);

        /* restart the watch call */
        ReadDirectoryChangesW(wdir->handle, wdir->buf, RES_BUF_SIZE, FALSE, FILE_NOTIFY_CHANGE_LAST_WRITE, 0, &wdir->over, 0);
    }
}

void FileWatcher::Init(const WCHAR* fileFullPath)
{
    // if the thread already exists then stop it
    if (IsThreadRunning())
        SynchronousAbort();

    str::ReplacePtr(&filePath, fileFullPath);
    WCHAR *dirPath = path::GetDir(filePath);

    hDir = CreateFile(
        dirPath, // pointer to the directory containing the tex files
        FILE_LIST_DIRECTORY,                // access (read-write) mode
        FILE_SHARE_READ|FILE_SHARE_DELETE|FILE_SHARE_WRITE,  // share mode
        NULL, // security descriptor
        OPEN_EXISTING, // how to create
        FILE_FLAG_BACKUP_SEMANTICS  | FILE_FLAG_OVERLAPPED , // file attributes
        NULL); // file with attributes to copy
    free(dirPath);

    ZeroMemory(&overl, sizeof(overl));
    ZeroMemory(buffer, sizeof(buffer));
    overl.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

    // watch the directory
    ReadDirectoryChangesW(
         hDir, /* handle to directory */
         &buffer[curBuffer], /* read results buffer */
         sizeof(buffer[curBuffer]), /* length of buffer */
         FALSE, /* monitoring option */
         //FILE_NOTIFY_CHANGE_CREATION|
         FILE_NOTIFY_CHANGE_LAST_WRITE, /* filter conditions */
         NULL, /* bytes returned */
         &overl, /* overlapped buffer */
         NULL); /* completion routine */
}

void CDirectoryMonitor::WatchDirectoryInternal(ULONG_PTR dwParam)
{
	CDirInfo	*pDirInfo = NULL;

	pDirInfo = reinterpret_cast<CDirInfo *>(dwParam);

	if(pDirInfo->m_hDirectory == INVALID_HANDLE_VALUE)
	{
		free(pDirInfo->m_pData);

		return;
	}

	pDirInfo->m_FileNotifyBuffer = (FILE_NOTIFY_INFORMATION *)malloc(PRIMARY_BUFFER_SIZE);

	pDirInfo->m_bDirMonitored = ReadDirectoryChangesW(pDirInfo->m_hDirectory,
	pDirInfo->m_FileNotifyBuffer,PRIMARY_BUFFER_SIZE,
	pDirInfo->m_bWatchSubTree,pDirInfo->m_WatchFlags,NULL,&pDirInfo->m_Async,
	CompletionRoutine);

	if(!pDirInfo->m_bDirMonitored)
	{
		free(pDirInfo->m_FileNotifyBuffer);
		CancelIo(pDirInfo->m_hDirectory);
		CloseHandle(pDirInfo->m_hDirectory);
	}
}

void gep::DirectoryWatcher::doRead()
{
    memset(&m_overlapped, 0, sizeof(m_overlapped));
    ReadDirectoryChangesW(m_directoryHandle, m_buffer, GEP_ARRAY_SIZE(m_buffer),
        (m_watchSubdirs == WatchSubdirs::yes),
        m_filter, nullptr, &m_overlapped, nullptr);
}

//-----------------------------------------------------------------------------
static void start_watch(struct watch_entry * watch_entry_p) {
//-----------------------------------------------------------------------------
    BOOL start_read_result;

    memset(&watch_entry_p->overlap, 0, sizeof(watch_entry_p->overlap));	

    // start an overlapped 'read' to look for a filesystem change
    start_read_result = ReadDirectoryChangesW(
        watch_entry_p->hDirectory,
        watch_entry_p->changes_buffer,
        CHANGES_BUFFER_SIZE,
        TRUE,
        DIRECTORY_CHANGES_FILTER,
        NULL,
        (LPOVERLAPPED) watch_entry_p,
        NULL
    );

    if (!start_read_result) {
		DWORD err = GetLastError();
        report_error(L"ReadDirectoryChangesW", err);
		/* This error is reported for a handle to a file, meaning a folder has been
			recreated as a file after it was selected for backup.
		*/
		if (err != ERROR_INVALID_PARAMETER)
			ExitProcess(10);
    }

} // start_watch

void
sbWin32FileSystemWatcher::WatchNextChange()
{
  TRACE("%s", __FUNCTION__);
  DWORD const flags =
    FILE_NOTIFY_CHANGE_FILE_NAME |
    FILE_NOTIFY_CHANGE_DIR_NAME |
    FILE_NOTIFY_CHANGE_LAST_WRITE |
    FILE_NOTIFY_CHANGE_CREATION;

  if (mRootDirHandle != INVALID_HANDLE_VALUE) {
    BOOL result =
      ReadDirectoryChangesW(mRootDirHandle,
                            mBuffer,
                            BUFFER_LEN,
                            TRUE,  // watch subdirs
                            flags,
                            NULL,
                            &mOverlapped,
                            ReadDirectoryChangesWCallbackRoutine);
    if (!result) {
      NS_WARNING("ERROR: Could not ReadDirectoryChangesW()");
      if (mRootDirHandle != INVALID_HANDLE_VALUE) {
        CloseHandle(mRootDirHandle);
        mRootDirHandle = INVALID_HANDLE_VALUE;
      }
    }
  }
}

static int beginMonitor(VPLFS_MonitorHandle_t* handle)
{
    // VPL_REPORT_INFO("beginMonitor called");
    int rv = 0;
    handle->overlapped.Internal = 0;
    handle->overlapped.InternalHigh = 0;
    handle->overlapped.Offset = 0;
    handle->overlapped.OffsetHigh = 0;
    handle->overlapped.hEvent = handle;  // hEvent not used by system, used as ctx ptr.
#ifdef VPL_PLAT_IS_WINRT
    // TODO: using WinRT APIs to implement file monitor
    rv = VPL_ERR_NOOP;
#else
    if(!ReadDirectoryChangesW(handle->hDir,
                              handle->pBuffer, //<--FILE_NOTIFY_INFORMATION records are put into this buffer
                              handle->nBufferLength,
                              TRUE,
                              FILE_NOTIFY_CHANGE_FILE_NAME|
                                  FILE_NOTIFY_CHANGE_DIR_NAME|
                                  FILE_NOTIFY_CHANGE_SIZE|
                                  FILE_NOTIFY_CHANGE_LAST_WRITE|
                                  FILE_NOTIFY_CHANGE_CREATION,
                              NULL, // Only defined for synchronous calls.
                              &handle->overlapped,
                              &ChDirCompletionRoutine) )
    {
       rv = VPLError_GetLastWinError();
    }
#endif
    return rv;
}

static unsigned int __stdcall
tr_watchdir_win32_thread (void * context)
{
  const tr_watchdir_t handle = context;
  tr_watchdir_win32 * const backend = BACKEND_UPCAST (tr_watchdir_get_backend (handle));
  DWORD bytes_transferred;

  while (tr_get_overlapped_result_ex (backend->fd, &backend->overlapped, &bytes_transferred,
                                      INFINITE, FALSE))
    {
      PFILE_NOTIFY_INFORMATION info = (PFILE_NOTIFY_INFORMATION) backend->buffer;

      while (info->NextEntryOffset != 0)
        *((BYTE **) &info) += info->NextEntryOffset;

      info->NextEntryOffset = bytes_transferred - ((BYTE *) info - (BYTE *) backend->buffer);

      send (backend->notify_pipe[1], (const char *) backend->buffer, bytes_transferred, 0);

      if (!ReadDirectoryChangesW (backend->fd, backend->buffer, sizeof (backend->buffer), FALSE,
                                  WIN32_WATCH_MASK, NULL, &backend->overlapped, NULL))
        {
          log_error ("Failed to read directory changes");
          return 0;
        }
    }

  if (GetLastError () != ERROR_OPERATION_ABORTED)
    log_error ("Failed to wait for directory changes");

  return 0;
}

static void uv_fs_event_queue_readdirchanges(uv_loop_t* loop,
    uv_fs_event_t* handle) {
  assert(handle->dir_handle != INVALID_HANDLE_VALUE);
  assert(!handle->req_pending);

  memset(&(handle->req.u.io.overlapped), 0,
         sizeof(handle->req.u.io.overlapped));
  if (!ReadDirectoryChangesW(handle->dir_handle,
                             handle->buffer,
                             uv_directory_watcher_buffer_size,
                             (handle->flags & UV_FS_EVENT_RECURSIVE) ? TRUE : FALSE,
                             FILE_NOTIFY_CHANGE_FILE_NAME      |
                               FILE_NOTIFY_CHANGE_DIR_NAME     |
                               FILE_NOTIFY_CHANGE_ATTRIBUTES   |
                               FILE_NOTIFY_CHANGE_SIZE         |
                               FILE_NOTIFY_CHANGE_LAST_WRITE   |
                               FILE_NOTIFY_CHANGE_LAST_ACCESS  |
                               FILE_NOTIFY_CHANGE_CREATION     |
                               FILE_NOTIFY_CHANGE_SECURITY,
                             NULL,
                             &handle->req.u.io.overlapped,
                             NULL)) {
    /* Make this req pending reporting an error. */
    SET_REQ_ERROR(&handle->req, GetLastError());
    uv_insert_pending_req(loop, (uv_req_t*)&handle->req);
  }

  handle->req_pending = 1;
}

int FileSystemWatcherTask::task()
{
	m_handle = CreateFile(m_path,
		FILE_LIST_DIRECTORY,
		FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
		nullptr,
		OPEN_EXISTING,
		FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
		nullptr);
	if (m_handle == INVALID_HANDLE_VALUE) return -1;

	Lumix::setMemory(&m_overlapped, 0, sizeof(m_overlapped));
	m_overlapped.hEvent = this;
	m_finished = false;
	while (!m_finished)
	{
		PROFILE_BLOCK("Change handling");
		BOOL status = ReadDirectoryChangesW(m_handle,
			m_info,
			sizeof(m_info),
			TRUE,
			READ_DIR_CHANGE_FILTER,
			&m_received,
			&m_overlapped,
			&notif);
		if (status == FALSE) break;
		SleepEx(INFINITE, TRUE);
	}
	return 0;
}

DWORD WINAPI FileSystemWatcher::Routine( LPVOID lParam )
{
    FileSystemWatcher* pFsw = (FileSystemWatcher*)lParam;
	CString tem1,tem2;
	CString str = (_T("[") + pFsw->WatchedDir + "] 开始监视!");
    pFsw->hDir = CreateFile(
        pFsw->WatchedDir,
        GENERIC_READ|GENERIC_WRITE,
        FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
        NULL,
        OPEN_EXISTING,
        FILE_FLAG_BACKUP_SEMANTICS,
        NULL
    );
    if( INVALID_HANDLE_VALUE == pFsw->hDir ) return false;

    char buf[ 2*(sizeof(FILE_NOTIFY_INFORMATION)+MAX_PATH) ];
    FILE_NOTIFY_INFORMATION* pNotify=(FILE_NOTIFY_INFORMATION *)buf;
    DWORD BytesReturned;
    while(true)
    {
        if( ReadDirectoryChangesW( pFsw->hDir,
            pNotify,
            sizeof(buf),
            true,
            FILE_NOTIFY_CHANGE_FILE_NAME|
            FILE_NOTIFY_CHANGE_DIR_NAME|
            FILE_NOTIFY_CHANGE_ATTRIBUTES|
            FILE_NOTIFY_CHANGE_SIZE|
            FILE_NOTIFY_CHANGE_LAST_WRITE|
            FILE_NOTIFY_CHANGE_LAST_ACCESS|
            FILE_NOTIFY_CHANGE_CREATION|
            FILE_NOTIFY_CHANGE_SECURITY,
            &BytesReturned,
            NULL,
            NULL ) )
        {
            char tmp[MAX_PATH], str1[MAX_PATH], str2[MAX_PATH];
            memset( tmp, 0, sizeof(tmp) );
            WideCharToMultiByte( CP_ACP,0,pNotify->FileName,pNotify->FileNameLength/2,tmp,99,NULL,NULL );
            strcpy_s( str1,260, tmp );

            if( 0 != pNotify->NextEntryOffset )
            {
                PFILE_NOTIFY_INFORMATION p = (PFILE_NOTIFY_INFORMATION)((char*)pNotify+pNotify->NextEntryOffset);
                memset( tmp, 0, sizeof(tmp) );
                WideCharToMultiByte( CP_ACP,0,p->FileName,p->FileNameLength/2,tmp,99,NULL,NULL );
                strcpy_s( str2,260, tmp );
            }
			tem1= str1;
			tem2= str2;
            pFsw->DealFunc((ACTION)pNotify->Action, tem1, tem2);
        } else
        {
            break;
        }
    }
    return 0;
}

VOID CFileMonitorRequest::CheckFileChange()
{
    DWORD dwBytes = 0;
    if ( FALSE == ReadDirectoryChangesW( m_hMonitorPath , &m_vecShareMem[0] , (DWORD)m_vecShareMem.size() , m_bRecursive , m_dwFilter , 
        &dwBytes , &m_overlapped , CFileMonitorRequest::OnChangeComplete ) )
    {
        CWUtils::ShowDebugMsg();
    }
}

bool FileMon::monitor(const std::string &path) {
#ifdef WIN32
#ifdef UNICODE
  wchar_t path2[512];
  MultiByteToWideChar(CP_ACP,0,path.c_str(),-1,path2,512);
#else
  const char *path2=path.c_str();
#endif

  WatchStruct* pWatch;
  size_t ptrsize = sizeof(*pWatch);
  pWatch = static_cast<WatchStruct*>(HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,ptrsize));

  pWatch->mDirHandle = CreateFile(path2,FILE_LIST_DIRECTORY,
    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,NULL,
    OPEN_EXISTING,FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,NULL);

  pWatch->fileMon=this;

  if(pWatch->mDirHandle != INVALID_HANDLE_VALUE) {
    pWatch->mOverlapped.hEvent = CreateEvent(NULL,TRUE,FALSE,NULL);
    pWatch->mNotifyFilter = FILE_NOTIFY_CHANGE_CREATION|FILE_NOTIFY_CHANGE_LAST_WRITE|FILE_NOTIFY_CHANGE_FILE_NAME;

    if(ReadDirectoryChangesW(
      pWatch->mDirHandle,pWatch->mBuffer,sizeof(pWatch->mBuffer),FALSE,
      pWatch->mNotifyFilter,NULL,&pWatch->mOverlapped,WatchCallback) != 0) {
      pWatch->mDirName=path;
      mWatches.insert(std::make_pair(path,pWatch));
      return true;
    } else {
      CloseHandle(pWatch->mOverlapped.hEvent);
      CloseHandle(pWatch->mDirHandle);
    }
  }

  HeapFree(GetProcessHeap(),0,pWatch);
  return false;
#endif

#ifdef LINUX
  int watch = inotify_add_watch(notify,path.c_str(),IN_CLOSE_WRITE | IN_MOVED_TO | IN_CREATE | IN_MOVED_FROM | IN_DELETE);

  if(watch < 0) {
    if(errno == ENOENT) {
      std::cout << "File monitor: File/dir not found error.\n";
      return false;
    } else {
      std::cout << "File monitor: " << strerror(errno) << std::endl;;
      return false;
    }
  } else {
    watchMap[watch]=path;
  }
  return true;
#endif
}