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     int flags = Watcher2NativeFlags(watch.GetFlags());
 140     int ret = ReadDirectoryChangesW(watch.GetHandle(), watch.GetBuffer(),
 141                                     wxFSWatchEntryMSW::BUFFER_SIZE, FALSE,
 142                                     flags, NULL,
 143                                     watch.GetOverlapped(), NULL);
 144     if (!ret)
 145     {
 146         wxLogSysError(_("Unable to set up watch for '%s'"),
 147                         watch.GetPath());
 148     }
 149
 150     return ret != 0;
 151 }
 152
 153 // TODO we should only specify those flags, which interest us
 154 // this needs a bit of thinking, quick impl for now
 155 int wxFSWatcherImplMSW::Watcher2NativeFlags(int WXUNUSED(flags))
 156 {
 157     static DWORD all_events = FILE_NOTIFY_CHANGE_FILE_NAME |
 158             FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_ATTRIBUTES |
 159             FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE |
 160             FILE_NOTIFY_CHANGE_LAST_ACCESS | FILE_NOTIFY_CHANGE_CREATION |
 161             FILE_NOTIFY_CHANGE_SECURITY;
 162
 163     return all_events;
 164 }
 165
 166
 167 // ============================================================================
 168 // wxFSWatcherImplMSW helper classes implementation
 169 // ============================================================================
 170
 171 wxIOCPThread::wxIOCPThread(wxFSWatcherImplMSW* service, wxIOCPService* iocp) :
 172     wxThread(wxTHREAD_JOINABLE),
 173     m_service(service), m_iocp(iocp)
 174 {
 175 }
 176
 177 // finishes this thread
 178 bool wxIOCPThread::Finish()
 179 {
 180     wxLogTrace(wxTRACE_FSWATCHER, "Posting empty status!");
 181
 182     // send "empty" packet to i/o completion port, just to wake
 183     return m_iocp->PostEmptyStatus();
 184 }
 185
 186 wxThread::ExitCode wxIOCPThread::Entry()
 187 {
 188     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] Started IOCP thread");
 189
 190     // read events in a loop until we get false, which means we should exit
 191     while ( ReadEvents() );
 192
 193     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] Ended IOCP thread");
 194     return (ExitCode)0;
 195 }
 196
 197 // wait for events to occur, read them and send to interested parties
 198 // returns false it empty status was read, which means we whould exit
 199 //         true otherwise
 200 bool wxIOCPThread::ReadEvents()
 201 {
 202     unsigned long count = 0;
 203     wxFSWatchEntryMSW* watch = NULL;
 204     OVERLAPPED* overlapped = NULL;
 205     if (!m_iocp->GetStatus(&count, &watch, &overlapped))
 206         return true; // error was logged already, we don't want to exit
 207
 208     // this is our exit condition, so we return false
 209     if (!count && !watch && !overlapped)
 210         return false;
 211
 212     // in case of spurious wakeup
 213     if (!count || !watch)
 214         return true;
 215
 216     wxLogTrace( wxTRACE_FSWATCHER, "[iocp] Read entry: path='%s'",
 217                 watch->GetPath());
 218
 219     // First check if we're still interested in this watch, we could have
 220     // removed it in the meanwhile.
 221     if ( m_iocp->CompleteRemoval(watch) )
 222         return true;
 223
 224     // extract events from buffer info our vector container
 225     wxVector<wxEventProcessingData> events;
 226     const char* memory = static_cast<const char*>(watch->GetBuffer());
 227     int offset = 0;
 228     do
 229     {
 230         const FILE_NOTIFY_INFORMATION* e =
 231               static_cast<const FILE_NOTIFY_INFORMATION*>((const void*)memory);
 232
 233         events.push_back(wxEventProcessingData(e, watch));
 234
 235         offset = e->NextEntryOffset;
 236         memory += offset;
 237     }
 238     while (offset);
 239
 240     // process events
 241     ProcessNativeEvents(events);
 242
 243     // reissue the watch. ignore possible errors, we will return true anyway
 244     (void) m_service->SetUpWatch(*watch);
 245
 246     return true;
 247 }
 248
 249 void wxIOCPThread::ProcessNativeEvents(wxVector<wxEventProcessingData>& events)
 250 {
 251     wxVector<wxEventProcessingData>::iterator it = events.begin();
 252     for ( ; it != events.end(); ++it )
 253     {
 254         const FILE_NOTIFY_INFORMATION& e = *(it->nativeEvent);
 255         const wxFSWatchEntryMSW* watch = it->watch;
 256
 257         wxLogTrace( wxTRACE_FSWATCHER, "[iocp] %s",
 258                     FileNotifyInformationToString(e));
 259
 260         int nativeFlags = e.Action;
 261         int flags = Native2WatcherFlags(nativeFlags);
 262         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 263         {
 264             // TODO think about this...do we ever have any errors to report?
 265             wxString errMsg = "Error occurred";
 266             wxFileSystemWatcherEvent event(flags, errMsg);
 267             SendEvent(event);
 268         }
 269         // filter out ignored events and those not asked for.
 270         // we never filter out warnings or exceptions
 271         else if ((flags == 0) || !(flags & watch->GetFlags()))
 272         {
 273             return;
 274         }
 275         // rename case
 276         else if (nativeFlags == FILE_ACTION_RENAMED_OLD_NAME)
 277         {
 278             wxFileName oldpath = GetEventPath(*watch, e);
 279             wxFileName newpath;
 280
 281             // newpath should be in the next entry. what if there isn't?
 282             ++it;
 283             if ( it != events.end() )
 284             {
 285                 newpath = GetEventPath(*(it->watch), *(it->nativeEvent));
 286             }
 287             wxFileSystemWatcherEvent event(flags, oldpath, newpath);
 288             SendEvent(event);
 289         }
 290         // all other events
 291         else
 292         {
 293             // CHECK I heard that returned path can be either in short on long
 294             // form...need to account for that!
 295             wxFileName path = GetEventPath(*watch, e);
 296             wxFileSystemWatcherEvent event(flags, path, path);
 297             SendEvent(event);
 298         }
 299     }
 300 }
 301
 302 void wxIOCPThread::SendEvent(wxFileSystemWatcherEvent& evt)
 303 {
 304     wxLogTrace(wxTRACE_FSWATCHER, "[iocp] EVT: %s", evt.ToString());
 305     m_service->SendEvent(evt);
 306 }
 307
 308 int wxIOCPThread::Native2WatcherFlags(int flags)
 309 {
 310     static const int flag_mapping[][2] = {
 311         { FILE_ACTION_ADDED,            wxFSW_EVENT_CREATE },
 312         { FILE_ACTION_REMOVED,          wxFSW_EVENT_DELETE },
 313
 314         // TODO take attributes into account to see what happened
 315         { FILE_ACTION_MODIFIED,         wxFSW_EVENT_MODIFY },
 316
 317         { FILE_ACTION_RENAMED_OLD_NAME, wxFSW_EVENT_RENAME },
 318
 319         // ignored as it should always be matched with ***_OLD_NAME
 320         { FILE_ACTION_RENAMED_NEW_NAME, 0 },
 321     };
 322
 323     for (unsigned int i=0; i < WXSIZEOF(flag_mapping); ++i) {
 324         if (flags == flag_mapping[i][0])
 325             return flag_mapping[i][1];
 326     }
 327
 328     // never reached
 329     wxFAIL_MSG(wxString::Format("Unknown file notify change %u", flags));
 330     return -1;
 331 }
 332
 333 wxString wxIOCPThread::FileNotifyInformationToString(
 334                                               const FILE_NOTIFY_INFORMATION& e)
 335 {
 336     wxString fname(e.FileName, e.FileNameLength / sizeof(e.FileName[0]));
 337     return wxString::Format("Event: offset=%d, action=%d, len=%d, "
 338                             "name(approx)='%s'", e.NextEntryOffset, e.Action,
 339                             e.FileNameLength, fname);
 340 }
 341
 342 wxFileName wxIOCPThread::GetEventPath(const wxFSWatchEntryMSW& watch,
 343                                       const FILE_NOTIFY_INFORMATION& e)
 344 {
 345     wxFileName path = watch.GetPath();
 346     if (path.IsDir())
 347     {
 348         wxString rel(e.FileName, e.FileNameLength / sizeof(e.FileName[0]));
 349         int pathFlags = wxPATH_GET_VOLUME | wxPATH_GET_SEPARATOR;
 350         path = wxFileName(path.GetPath(pathFlags) + rel);
 351     }
 352     return path;
 353 }
 354
 355
 356 // ============================================================================
 357 // wxMSWFileSystemWatcher implementation
 358 // ============================================================================
 359
 360 wxMSWFileSystemWatcher::wxMSWFileSystemWatcher() :
 361     wxFileSystemWatcherBase()
 362 {
 363     (void) Init();
 364 }
 365
 366 wxMSWFileSystemWatcher::wxMSWFileSystemWatcher(const wxFileName& path,
 367                                                int events) :
 368     wxFileSystemWatcherBase()
 369 {
 370     if (!Init())
 371         return;
 372
 373     Add(path, events);
 374 }
 375
 376 bool wxMSWFileSystemWatcher::Init()
 377 {
 378     m_service = new wxFSWatcherImplMSW(this);
 379     bool ret = m_service->Init();
 380     if (!ret)
 381     {
 382         delete m_service;
 383     }
 384
 385     return ret;
 386 }
 387
 388 #endif // wxUSE_FSWATCHER