src/msw/fswatcher.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/fswatcher.cpp
   3 // Purpose:     wxMSWFileSystemWatcher
   4 // Author:      Bartosz Bekier
   5 // Created:     2009-05-26
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2009 Bartosz Bekier <bartosz.bekier@gmail.com>
   8 // Licence:     wxWindows licence
   9 /////////////////////////////////////////////////////////////////////////////
  10
  11 // For compilers that support precompilation, includes "wx.h".
  12 #include "wx/wxprec.h"
  13
  14 #ifdef __BORLANDC__
  15     #pragma hdrstop
  16 #endif
  17
  18 #if wxUSE_FSWATCHER
  19
  20 #include "wx/fswatcher.h"
  21 #include "wx/thread.h"
  22 #include "wx/sharedptr.h"
  23 #include "wx/msw/fswatcher.h"
  24 #include "wx/msw/private.h"
  25 #include "wx/private/fswatcher.h"
  26
  27 // ============================================================================
  28 // wxFSWatcherImplMSW implementation
  29 // ============================================================================
  30
  31 class wxFSWatcherImplMSW : public wxFSWatcherImpl
  32 {
  33 public:
  34     wxFSWatcherImplMSW(wxFileSystemWatcherBase* watcher);
  35
  36     virtual ~wxFSWatcherImplMSW();
  37
  38     bool SetUpWatch(wxFSWatchEntryMSW& watch);
  39
  40     void SendEvent(wxFileSystemWatcherEvent& evt);
  41
  42 protected:
  43     bool Init();
  44
  45     // adds watch to be monitored for file system changes
  46     virtual bool DoAdd(wxSharedPtr<wxFSWatchEntryMSW> watch);
  47
  48     virtual bool DoRemove(wxSharedPtr<wxFSWatchEntryMSW> watch);
  49
  50 private:
  51     bool DoSetUpWatch(wxFSWatchEntryMSW& watch);
  52
  53     static int Watcher2NativeFlags(int flags);
  54
  55     wxIOCPService m_iocp;
  56     wxIOCPThread m_workerThread;
  57 };
  58
  59 wxFSWatcherImplMSW::wxFSWatcherImplMSW(wxFileSystemWatcherBase* watcher) :
  60     wxFSWatcherImpl(watcher),
  61     m_workerThread(this, &m_iocp)
  62 {
  63 }
  64
  65 wxFSWatcherImplMSW::~wxFSWatcherImplMSW()
  66 {
  67     // order the worker thread to finish & wait
  68     m_workerThread.Finish();
  69     if (m_workerThread.Wait() != 0)
  70     {
  71         wxLogError(_("Ungraceful worker thread termination"));
  72     }
  73
  74     // remove all watches
  75     (void) RemoveAll();
  76 }
  77
  78 bool wxFSWatcherImplMSW::Init()
  79 {
  80     wxCHECK_MSG( !m_workerThread.IsAlive(), false,
  81                  "Watcher service is already initialized" );
  82
  83     if (m_workerThread.Create() != wxTHREAD_NO_ERROR)
  84     {
  85         wxLogError(_("Unable to create IOCP worker thread"));
  86         return false;
  87     }
  88
  89     // we have valid iocp service and thread
  90     if (m_workerThread.Run() != wxTHREAD_NO_ERROR)
  91     {
  92         wxLogError(_("Unable to start IOCP worker thread"));
  93         return false;
  94     }
  95
  96     return true;
  97 }
  98
  99 // adds watch to be monitored for file system changes
 100 bool wxFSWatcherImplMSW::DoAdd(wxSharedPtr<wxFSWatchEntryMSW> watch)
 101 {
 102     // setting up wait for directory changes
 103     if (!DoSetUpWatch(*watch))
 104         return false;
 105
 106     // associating handle with completion port
 107     return m_iocp.Add(watch);
 108 }
 109
 110 bool
 111 wxFSWatcherImplMSW::DoRemove(wxSharedPtr<wxFSWatchEntryMSW> watch)
 112 {
 113     return m_iocp.ScheduleForRemoval(watch);
 114 }
 115
 116 // TODO ensuring that we have not already set watch for this handle/dir?
 117 bool wxFSWatcherImplMSW::SetUpWatch(wxFSWatchEntryMSW& watch)
 118 {
 119     wxCHECK_MSG( watch.IsOk(), false, "Invalid watch" );
 120     if (m_watches.find(watch.GetPath()) == m_watches.end())
 121     {
 122         wxLogTrace(wxTRACE_FSWATCHER, "Path '%s' is not watched",
 123                    watch.GetPath());
 124         return false;
 125     }
 126
 127     wxLogTrace(wxTRACE_FSWATCHER, "Setting up watch for file system changes...");
 128     return DoSetUpWatch(watch);
 129 }
 130
 131 void wxFSWatcherImplMSW::SendEvent(wxFileSystemWatcherEvent& evt)
 132 {
 133     // called from worker thread, so posting event in thread-safe way
 134     wxQueueEvent(m_watcher->GetOwner(), evt.Clone());
 135 }
 136
 137 bool wxFSWatcherImplMSW::DoSetUpWatch(wxFSWatchEntryMSW& watch)
 138 {
 139     BOOL bWatchSubtree wxDUMMY_INITIALIZE(FALSE);
 140
 141     switch ( watch.GetType() )
 142     {
 143         case wxFSWPath_File:
 144             wxLogError(_("Monitoring individual files for changes is not "
 145                          "supported currently."));
 146             return false;
 147
 148         case wxFSWPath_Dir:
 149             bWatchSubtree = FALSE;
 150             break;
 151
 152         case wxFSWPath_Tree:
 153             bWatchSubtree = TRUE;
 154             break;
 155
 156         case wxFSWPath_None:
 157             wxFAIL_MSG( "Invalid watch type." );
 158             return false;
 159     }
 160
 161     int flags = Watcher2NativeFlags(watch.GetFlags());
 162     int ret = ReadDirectoryChangesW(watch.GetHandle(), watch.GetBuffer(),
 163                                     wxFSWatchEntryMSW::BUFFER_SIZE,
 164                                     bWatchSubtree,
 165                                     flags, NULL,
 166                                     watch.GetOverlapped(), NULL);
 167     if (!ret)
 168     {
 169         wxLogSysError(_("Unable to set up watch for '%s'"),
 170                         watch.GetPath());
 171     }
 172
 173     return ret != 0;
 174 }
 175
 176 // TODO we should only specify those flags, which interest us
 177 // this needs a bit of thinking, quick impl for now
 178 int wxFSWatcherImplMSW::Watcher2NativeFlags(int WXUNUSED(flags))
 179 {
 180     static DWORD all_events = FILE_NOTIFY_CHANGE_FILE_NAME |
 181             FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_ATTRIBUTES |
 182             FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE |
 183             FILE_NOTIFY_CHANGE_LAST_ACCESS | FILE_NOTIFY_CHANGE_CREATION |
 184             FILE_NOTIFY_CHANGE_SECURITY;
 185
 186     return all_events;
 187 }
 188
 189
 190 // ============================================================================
 191 // wxFSWatcherImplMSW helper classes implementation
 192 // ============================================================================
 193
 194 wxIOCPThread::wxIOCPThread(wxFSWatcherImplMSW* service, wxIOCPService* iocp) :
 195     wxThread(wxTHREAD_JOINABLE),
 196     m_service(service), m_iocp(iocp)
 197 {
 198 }
 199
 200 // finishes this thread
 201 bool wxIOCPThread::Finish()
 202 {
 203     wxLogTrace(wxTRACE_FSWATCHER, "Posting empty status!");
 204
 205     // send "empty" packet to i/o completion port, just to wake
 206     return m_iocp->PostEmptyStatus();
 207 }
 208
 209 wxThread::ExitCode wxIOCPThread::Entry()
 210 {
 211     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] Started IOCP thread");
 212
 213     // read events in a loop until we get false, which means we should exit
 214     while ( ReadEvents() );
 215
 216     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] Ended IOCP thread");
 217     return (ExitCode)0;
 218 }
 219
 220 // wait for events to occur, read them and send to interested parties
 221 // returns false it empty status was read, which means we whould exit
 222 //         true otherwise
 223 bool wxIOCPThread::ReadEvents()
 224 {
 225     unsigned long count = 0;
 226     wxFSWatchEntryMSW* watch = NULL;
 227     OVERLAPPED* overlapped = NULL;
 228     if (!m_iocp->GetStatus(&count, &watch, &overlapped))
 229         return true; // error was logged already, we don't want to exit
 230
 231     // this is our exit condition, so we return false
 232     if (!count && !watch && !overlapped)
 233         return false;
 234
 235     // in case of spurious wakeup
 236     if (!count || !watch)
 237         return true;
 238
 239     wxLogTrace( wxTRACE_FSWATCHER, "[iocp] Read entry: path='%s'",
 240                 watch->GetPath());
 241
 242     // First check if we're still interested in this watch, we could have
 243     // removed it in the meanwhile.
 244     if ( m_iocp->CompleteRemoval(watch) )
 245         return true;
 246
 247     // extract events from buffer info our vector container
 248     wxVector<wxEventProcessingData> events;
 249     const char* memory = static_cast<const char*>(watch->GetBuffer());
 250     int offset = 0;
 251     do
 252     {
 253         const FILE_NOTIFY_INFORMATION* e =
 254               static_cast<const FILE_NOTIFY_INFORMATION*>((const void*)memory);
 255
 256         events.push_back(wxEventProcessingData(e, watch));
 257
 258         offset = e->NextEntryOffset;
 259         memory += offset;
 260     }
 261     while (offset);
 262
 263     // process events
 264     ProcessNativeEvents(events);
 265
 266     // reissue the watch. ignore possible errors, we will return true anyway
 267     (void) m_service->SetUpWatch(*watch);
 268
 269     return true;
 270 }
 271
 272 void wxIOCPThread::ProcessNativeEvents(wxVector<wxEventProcessingData>& events)
 273 {
 274     wxVector<wxEventProcessingData>::iterator it = events.begin();
 275     for ( ; it != events.end(); ++it )
 276     {
 277         const FILE_NOTIFY_INFORMATION& e = *(it->nativeEvent);
 278         const wxFSWatchEntryMSW* watch = it->watch;
 279
 280         wxLogTrace( wxTRACE_FSWATCHER, "[iocp] %s",
 281                     FileNotifyInformationToString(e));
 282
 283         int nativeFlags = e.Action;
 284         int flags = Native2WatcherFlags(nativeFlags);
 285         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 286         {
 287             // TODO think about this...do we ever have any errors to report?
 288             wxString errMsg = "Error occurred";
 289             wxFileSystemWatcherEvent event(flags, errMsg);
 290             SendEvent(event);
 291         }
 292         // filter out ignored events and those not asked for.
 293         // we never filter out warnings or exceptions
 294         else if ((flags == 0) || !(flags & watch->GetFlags()))
 295         {
 296             return;
 297         }
 298         // rename case
 299         else if (nativeFlags == FILE_ACTION_RENAMED_OLD_NAME)
 300         {
 301             wxFileName oldpath = GetEventPath(*watch, e);
 302             wxFileName newpath;
 303
 304             // newpath should be in the next entry. what if there isn't?
 305             ++it;
 306             if ( it != events.end() )
 307             {
 308                 newpath = GetEventPath(*(it->watch), *(it->nativeEvent));
 309             }
 310             wxFileSystemWatcherEvent event(flags, oldpath, newpath);
 311             SendEvent(event);
 312         }
 313         // all other events
 314         else
 315         {
 316             // CHECK I heard that returned path can be either in short on long
 317             // form...need to account for that!
 318             wxFileName path = GetEventPath(*watch, e);
 319             wxFileSystemWatcherEvent event(flags, path, path);
 320             SendEvent(event);
 321         }
 322     }
 323 }
 324
 325 void wxIOCPThread::SendEvent(wxFileSystemWatcherEvent& evt)
 326 {
 327     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] EVT: %s", evt.ToString());
 328     m_service->SendEvent(evt);
 329 }
 330
 331 int wxIOCPThread::Native2WatcherFlags(int flags)
 332 {
 333     static const int flag_mapping[][2] = {
 334         { FILE_ACTION_ADDED,            wxFSW_EVENT_CREATE },
 335         { FILE_ACTION_REMOVED,          wxFSW_EVENT_DELETE },
 336
 337         // TODO take attributes into account to see what happened
 338         { FILE_ACTION_MODIFIED,         wxFSW_EVENT_MODIFY },
 339
 340         { FILE_ACTION_RENAMED_OLD_NAME, wxFSW_EVENT_RENAME },
 341
 342         // ignored as it should always be matched with ***_OLD_NAME
 343         { FILE_ACTION_RENAMED_NEW_NAME, 0 },
 344     };
 345
 346     for (unsigned int i=0; i < WXSIZEOF(flag_mapping); ++i) {
 347         if (flags == flag_mapping[i][0])
 348             return flag_mapping[i][1];
 349     }
 350
 351     // never reached
 352     wxFAIL_MSG(wxString::Format("Unknown file notify change %u", flags));
 353     return -1;
 354 }
 355
 356 wxString wxIOCPThread::FileNotifyInformationToString(
 357                                               const FILE_NOTIFY_INFORMATION& e)
 358 {
 359     wxString fname(e.FileName, e.FileNameLength / sizeof(e.FileName[0]));
 360     return wxString::Format("Event: offset=%d, action=%d, len=%d, "
 361                             "name(approx)='%s'", e.NextEntryOffset, e.Action,
 362                             e.FileNameLength, fname);
 363 }
 364
 365 wxFileName wxIOCPThread::GetEventPath(const wxFSWatchEntryMSW& watch,
 366                                       const FILE_NOTIFY_INFORMATION& e)
 367 {
 368     wxFileName path = watch.GetPath();
 369     if (path.IsDir())
 370     {
 371         wxString rel(e.FileName, e.FileNameLength / sizeof(e.FileName[0]));
 372         int pathFlags = wxPATH_GET_VOLUME | wxPATH_GET_SEPARATOR;
 373         path = wxFileName(path.GetPath(pathFlags) + rel);
 374     }
 375     return path;
 376 }
 377
 378
 379 // ============================================================================
 380 // wxMSWFileSystemWatcher implementation
 381 // ============================================================================
 382
 383 wxMSWFileSystemWatcher::wxMSWFileSystemWatcher() :
 384     wxFileSystemWatcherBase()
 385 {
 386     (void) Init();
 387 }
 388
 389 wxMSWFileSystemWatcher::wxMSWFileSystemWatcher(const wxFileName& path,
 390                                                int events) :
 391     wxFileSystemWatcherBase()
 392 {
 393     if (!Init())
 394         return;
 395
 396     Add(path, events);
 397 }
 398
 399 bool wxMSWFileSystemWatcher::Init()
 400 {
 401     m_service = new wxFSWatcherImplMSW(this);
 402     bool ret = m_service->Init();
 403     if (!ret)
 404     {
 405         delete m_service;
 406     }
 407
 408     return ret;
 409 }
 410
 411 bool
 412 wxMSWFileSystemWatcher::AddTree(const wxFileName& path,
 413                                 int events,
 414                                 const wxString& filter)
 415 {
 416     if ( !filter.empty() )
 417     {
 418         // Use the inefficient generic version as we can only monitor
 419         // everything under the given directory.
 420         //
 421         // Notice that it would probably be better to still monitor everything
 422         // natively and filter out the changes we're not interested in.
 423         return wxFileSystemWatcherBase::AddTree(path, events, filter);
 424     }
 425
 426
 427     if ( !path.DirExists() )
 428     {
 429         wxLogError(_("Can't monitor non-existent directory \"%s\" for changes."),
 430                    path.GetFullPath());
 431         return false;
 432     }
 433
 434     return DoAdd(path, events, wxFSWPath_Tree);
 435 }
 436
 437 #endif // wxUSE_FSWATCHER