src/unix/fswatcher_kqueue.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/unix/fswatcher_kqueue.cpp
   3 // Purpose:     kqueue-based wxFileSystemWatcher implementation
   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
  22 #ifdef wxHAS_KQUEUE
  23
  24 #include <sys/types.h>
  25 #include <sys/event.h>
  26
  27 #include "wx/dynarray.h"
  28 #include "wx/evtloop.h"
  29 #include "wx/evtloopsrc.h"
  30
  31 #include "wx/private/fswatcher.h"
  32
  33 // ============================================================================
  34 // wxFSWSourceHandler helper class
  35 // ============================================================================
  36
  37 class wxFSWatcherImplKqueue;
  38
  39 /**
  40  * Handler for handling i/o from inotify descriptor
  41  */
  42 class wxFSWSourceHandler : public wxEventLoopSourceHandler
  43 {
  44 public:
  45     wxFSWSourceHandler(wxFSWatcherImplKqueue* service) :
  46         m_service(service)
  47     {  }
  48
  49     virtual void OnReadWaiting();
  50     virtual void OnWriteWaiting();
  51     virtual void OnExceptionWaiting();
  52
  53 protected:
  54     wxFSWatcherImplKqueue* m_service;
  55 };
  56
  57 // ============================================================================
  58 // wxFSWatcherImpl implementation & helper wxFSWSourceHandler implementation
  59 // ============================================================================
  60
  61 /**
  62  * Helper class encapsulating inotify mechanism
  63  */
  64 class wxFSWatcherImplKqueue : public wxFSWatcherImpl
  65 {
  66 public:
  67     wxFSWatcherImplKqueue(wxFileSystemWatcherBase* watcher) :
  68         wxFSWatcherImpl(watcher),
  69         m_source(NULL),
  70         m_kfd(-1)
  71     {
  72         m_handler = new wxFSWSourceHandler(this);
  73     }
  74
  75     virtual ~wxFSWatcherImplKqueue()
  76     {
  77         // we close kqueue only if initialized before
  78         if (IsOk())
  79         {
  80             Close();
  81         }
  82
  83         delete m_handler;
  84     }
  85
  86     bool Init()
  87     {
  88         wxCHECK_MSG( !IsOk(), false,
  89                      "Kqueue appears to be already initialized" );
  90
  91         wxEventLoopBase *loop = wxEventLoopBase::GetActive();
  92         wxCHECK_MSG( loop, false, "File system watcher needs an active loop" );
  93
  94         // create kqueue
  95         m_kfd = kqueue();
  96         if (m_kfd == -1)
  97         {
  98             wxLogSysError(_("Unable to create kqueue instance"));
  99             return false;
 100         }
 101
 102         // create source
 103         m_source = loop->AddSourceForFD(m_kfd, m_handler, wxEVENT_SOURCE_INPUT);
 104
 105         return m_source != NULL;
 106     }
 107
 108     void Close()
 109     {
 110         wxCHECK_RET( IsOk(),
 111                     "Kqueue not initialized or invalid kqueue descriptor" );
 112
 113         if ( close(m_kfd) != 0 )
 114         {
 115             wxLogSysError(_("Error closing kqueue instance"));
 116         }
 117
 118         wxDELETE(m_source);
 119     }
 120
 121     virtual bool DoAdd(wxSharedPtr<wxFSWatchEntryKq> watch)
 122     {
 123         wxCHECK_MSG( IsOk(), false,
 124                     "Kqueue not initialized or invalid kqueue descriptor" );
 125
 126         struct kevent event;
 127         int action = EV_ADD | EV_ENABLE | EV_CLEAR | EV_ERROR;
 128         int flags = Watcher2NativeFlags(watch->GetFlags());
 129         EV_SET( &event, watch->GetFileDescriptor(), EVFILT_VNODE, action,
 130                 flags, 0, watch.get() );
 131
 132         // TODO more error conditions according to man
 133         // TODO best deal with the error here
 134         int ret = kevent(m_kfd, &event, 1, NULL, 0, NULL);
 135         if (ret == -1)
 136         {
 137             wxLogSysError(_("Unable to add kqueue watch"));
 138             return false;
 139         }
 140
 141         return true;
 142     }
 143
 144     virtual bool DoRemove(wxSharedPtr<wxFSWatchEntryKq> watch)
 145     {
 146         wxCHECK_MSG( IsOk(), false,
 147                     "Kqueue not initialized or invalid kqueue descriptor" );
 148
 149         // TODO more error conditions according to man
 150         // XXX closing file descriptor removes the watch. The logic resides in
 151         // the watch which is not nice, but effective and simple
 152         if ( !watch->Close() )
 153         {
 154             wxLogSysError(_("Unable to remove kqueue watch"));
 155             return false;
 156         }
 157
 158         return true;
 159     }
 160
 161     virtual bool RemoveAll()
 162     {
 163         wxFSWatchEntries::iterator it = m_watches.begin();
 164         for ( ; it != m_watches.end(); ++it )
 165         {
 166             (void) DoRemove(it->second);
 167         }
 168         m_watches.clear();
 169         return true;
 170     }
 171
 172     // return true if there was no error, false on error
 173     bool ReadEvents()
 174     {
 175         wxCHECK_MSG( IsOk(), false,
 176                     "Kqueue not initialized or invalid kqueue descriptor" );
 177
 178         // read events
 179         do
 180         {
 181             struct kevent event;
 182             struct timespec timeout = {0, 0};
 183             int ret = kevent(m_kfd, NULL, 0, &event, 1, &timeout);
 184             if (ret == -1)
 185             {
 186                 wxLogSysError(_("Unable to get events from kqueue"));
 187                 return false;
 188             }
 189             else if (ret == 0)
 190             {
 191                 return true;
 192             }
 193
 194             // we have event, so process it
 195             ProcessNativeEvent(event);
 196         }
 197         while (true);
 198
 199         // when ret>0 we still have events, when ret<=0 we return
 200         wxFAIL_MSG( "Never reached" );
 201         return true;
 202     }
 203
 204     bool IsOk() const
 205     {
 206         return m_source != NULL;
 207     }
 208
 209 protected:
 210     // returns all new dirs/files present in the immediate level of the dir
 211     // pointed by watch.GetPath(). "new" means created between the last time
 212     // the state of watch was computed and now
 213     void FindChanges(wxFSWatchEntryKq& watch,
 214                      wxArrayString& changedFiles,
 215                      wxArrayInt& changedFlags)
 216     {
 217         wxFSWatchEntryKq::wxDirState old = watch.GetLastState();
 218         watch.RefreshState();
 219         wxFSWatchEntryKq::wxDirState curr = watch.GetLastState();
 220
 221         // iterate over old/curr file lists and compute changes
 222         wxArrayString::iterator oit = old.files.begin();
 223         wxArrayString::iterator cit = curr.files.begin();
 224         for ( ; oit != old.files.end() && cit != curr.files.end(); )
 225         {
 226             if ( *cit == *oit )
 227             {
 228                 ++cit;
 229                 ++oit;
 230             }
 231             else if ( *cit <= *oit )
 232             {
 233                 changedFiles.push_back(*cit);
 234                 changedFlags.push_back(wxFSW_EVENT_CREATE);
 235                 ++cit;
 236             }
 237             else // ( *cit > *oit )
 238             {
 239                 changedFiles.push_back(*oit);
 240                 changedFlags.push_back(wxFSW_EVENT_DELETE);
 241                 ++oit;
 242             }
 243         }
 244
 245         // border conditions
 246         if ( oit == old.files.end() )
 247         {
 248             for ( ; cit != curr.files.end(); ++cit )
 249             {
 250                 changedFiles.push_back( *cit );
 251                 changedFlags.push_back(wxFSW_EVENT_CREATE);
 252             }
 253         }
 254         else if ( cit == curr.files.end() )
 255         {
 256             for ( ; oit != old.files.end(); ++oit )
 257             {
 258                 changedFiles.push_back( *oit );
 259                 changedFlags.push_back(wxFSW_EVENT_DELETE);
 260             }
 261         }
 262
 263         wxASSERT( changedFiles.size() == changedFlags.size() );
 264
 265 #if 0
 266         wxLogTrace(wxTRACE_FSWATCHER, "Changed files:");
 267         wxArrayString::iterator it = changedFiles.begin();
 268         wxArrayInt::iterator it2 = changedFlags.begin();
 269         for ( ; it != changedFiles.end(); ++it, ++it2)
 270         {
 271             wxString action = (*it2 == wxFSW_EVENT_CREATE) ?
 272                                 "created" : "deleted";
 273             wxLogTrace(wxTRACE_FSWATCHER, wxString::Format("File: '%s' %s",
 274                         *it, action));
 275         }
 276 #endif
 277     }
 278
 279     void ProcessNativeEvent(const struct kevent& e)
 280     {
 281         wxASSERT_MSG(e.udata, "Null user data associated with kevent!");
 282
 283         wxLogTrace(wxTRACE_FSWATCHER, "Event: ident=%d, filter=%d, flags=%u, "
 284                    "fflags=%u, data=%d, user_data=%p",
 285                    e.ident, e.filter, e.flags, e.fflags, e.data, e.udata);
 286
 287         // for ease of use
 288         wxFSWatchEntryKq& w = *(static_cast<wxFSWatchEntry*>(e.udata));
 289         int nflags = e.fflags;
 290
 291         // clear ignored flags
 292         nflags &= ~NOTE_REVOKE;
 293
 294         // TODO ignore events we didn't ask for + refactor this cascade ifs
 295         // check for events
 296         while ( nflags )
 297         {
 298             // when monitoring dir, this means create/delete
 299             const wxString basepath = w.GetPath();
 300             if ( nflags & NOTE_WRITE && wxDirExists(basepath) )
 301             {
 302                 // NOTE_LINK is set when the dir was created, but we
 303                 // don't care - we look for new names in directory
 304                 // regardless of type. Also, clear all this, because
 305                 // it cannot mean more by itself
 306                 nflags &= ~(NOTE_WRITE | NOTE_ATTRIB | NOTE_LINK);
 307
 308                 wxArrayString changedFiles;
 309                 wxArrayInt changedFlags;
 310                 FindChanges(w, changedFiles, changedFlags);
 311
 312                 wxArrayString::iterator it = changedFiles.begin();
 313                 wxArrayInt::iterator changeType = changedFlags.begin();
 314                 for ( ; it != changedFiles.end(); ++it, ++changeType )
 315                 {
 316                     const wxString fullpath = w.GetPath() +
 317                                                 wxFileName::GetPathSeparator() +
 318                                                   *it;
 319                     const wxFileName path(wxDirExists(fullpath)
 320                                             ? wxFileName::DirName(fullpath)
 321                                             : wxFileName::FileName(fullpath));
 322
 323                     wxFileSystemWatcherEvent event(*changeType, path, path);
 324                     SendEvent(event);
 325                 }
 326             }
 327             else if ( nflags & NOTE_RENAME )
 328             {
 329                 // CHECK it'd be only possible to detect name if we had
 330                 // parent files listing which we could confront with now and
 331                 // still we couldn't be sure we have the right name...
 332                 nflags &= ~NOTE_RENAME;
 333                 wxFileSystemWatcherEvent event(wxFSW_EVENT_RENAME,
 334                                         basepath, wxFileName());
 335                 SendEvent(event);
 336             }
 337             else if ( nflags & NOTE_WRITE || nflags & NOTE_EXTEND )
 338             {
 339                 nflags &= ~(NOTE_WRITE | NOTE_EXTEND);
 340                 wxFileSystemWatcherEvent event(wxFSW_EVENT_MODIFY,
 341                                         basepath, basepath);
 342                 SendEvent(event);
 343             }
 344             else if ( nflags & NOTE_DELETE )
 345             {
 346                 nflags &= ~(NOTE_DELETE);
 347                 wxFileSystemWatcherEvent event(wxFSW_EVENT_DELETE,
 348                                         basepath, basepath);
 349                 SendEvent(event);
 350             }
 351             else if ( nflags & NOTE_ATTRIB )
 352             {
 353                 nflags &= ~(NOTE_ATTRIB);
 354                 wxFileSystemWatcherEvent event(wxFSW_EVENT_ACCESS,
 355                                         basepath, basepath);
 356                 SendEvent(event);
 357             }
 358
 359             // clear any flags that won't mean anything by themselves
 360             nflags &= ~(NOTE_LINK);
 361         }
 362     }
 363
 364     void SendEvent(wxFileSystemWatcherEvent& evt)
 365     {
 366         m_watcher->GetOwner()->ProcessEvent(evt);
 367     }
 368
 369     static int Watcher2NativeFlags(int WXUNUSED(flags))
 370     {
 371         // TODO: it would be better to only subscribe to what we need
 372         return NOTE_DELETE | NOTE_WRITE | NOTE_EXTEND |
 373                NOTE_ATTRIB | NOTE_LINK | NOTE_RENAME |
 374                NOTE_REVOKE;
 375     }
 376
 377     wxFSWSourceHandler* m_handler;        // handler for kqueue event source
 378     wxEventLoopSource* m_source;          // our event loop source
 379
 380     // descriptor created by kqueue()
 381     int m_kfd;
 382 };
 383
 384
 385 // once we get signaled to read, actuall event reading occurs
 386 void wxFSWSourceHandler::OnReadWaiting()
 387 {
 388     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 389     m_service->ReadEvents();
 390 }
 391
 392 void wxFSWSourceHandler::OnWriteWaiting()
 393 {
 394     wxFAIL_MSG("We never write to kqueue descriptor.");
 395 }
 396
 397 void wxFSWSourceHandler::OnExceptionWaiting()
 398 {
 399     wxFAIL_MSG("We never receive exceptions on kqueue descriptor.");
 400 }
 401
 402
 403 // ============================================================================
 404 // wxKqueueFileSystemWatcher implementation
 405 // ============================================================================
 406
 407 wxKqueueFileSystemWatcher::wxKqueueFileSystemWatcher()
 408     : wxFileSystemWatcherBase()
 409 {
 410     Init();
 411 }
 412
 413 wxKqueueFileSystemWatcher::wxKqueueFileSystemWatcher(const wxFileName& path,
 414                                                      int events)
 415     : wxFileSystemWatcherBase()
 416 {
 417     if (!Init())
 418     {
 419         wxDELETE(m_service);
 420         return;
 421     }
 422
 423     Add(path, events);
 424 }
 425
 426 wxKqueueFileSystemWatcher::~wxKqueueFileSystemWatcher()
 427 {
 428 }
 429
 430 bool wxKqueueFileSystemWatcher::Init()
 431 {
 432     m_service = new wxFSWatcherImplKqueue(this);
 433     return m_service->Init();
 434 }
 435
 436 #endif // wxHAS_KQUEUE
 437
 438 #endif // wxUSE_FSWATCHER