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         bool ret = watch->Close();
 153         if (ret == -1)
 154         {
 155             wxLogSysError(_("Unable to remove kqueue watch"));
 156             return false;
 157         }
 158
 159         return true;
 160     }
 161
 162     virtual bool RemoveAll()
 163     {
 164         wxFSWatchEntries::iterator it = m_watches.begin();
 165         for ( ; it != m_watches.end(); ++it )
 166         {
 167             (void) DoRemove(it->second);
 168         }
 169         m_watches.clear();
 170         return true;
 171     }
 172
 173     // return true if there was no error, false on error
 174     bool ReadEvents()
 175     {
 176         wxCHECK_MSG( IsOk(), false,
 177                     "Kqueue not initialized or invalid kqueue descriptor" );
 178
 179         // read events
 180         do
 181         {
 182             struct kevent event;
 183             struct timespec timeout = {0, 0};
 184             int ret = kevent(m_kfd, NULL, 0, &event, 1, &timeout);
 185             if (ret == -1)
 186             {
 187                 wxLogSysError(_("Unable to get events from kqueue"));
 188                 return false;
 189             }
 190             else if (ret == 0)
 191             {
 192                 return true;
 193             }
 194
 195             // we have event, so process it
 196             ProcessNativeEvent(event);
 197         }
 198         while (true);
 199
 200         // when ret>0 we still have events, when ret<=0 we return
 201         wxFAIL_MSG( "Never reached" );
 202         return true;
 203     }
 204
 205     bool IsOk() const
 206     {
 207         return m_source != NULL;
 208     }
 209
 210 protected:
 211     // returns all new dirs/files present in the immediate level of the dir
 212     // pointed by watch.GetPath(). "new" means created between the last time
 213     // the state of watch was computed and now
 214     void FindChanges(wxFSWatchEntryKq& watch,
 215                      wxArrayString& changedFiles,
 216                      wxArrayInt& changedFlags)
 217     {
 218         wxFSWatchEntryKq::wxDirState old = watch.GetLastState();
 219         watch.RefreshState();
 220         wxFSWatchEntryKq::wxDirState curr = watch.GetLastState();
 221
 222         // iterate over old/curr file lists and compute changes
 223         wxArrayString::iterator oit = old.files.begin();
 224         wxArrayString::iterator cit = curr.files.begin();
 225         for ( ; oit != old.files.end() && cit != curr.files.end(); )
 226         {
 227             if ( *cit == *oit )
 228             {
 229                 ++cit;
 230                 ++oit;
 231             }
 232             else if ( *cit <= *oit )
 233             {
 234                 changedFiles.push_back(*cit);
 235                 changedFlags.push_back(wxFSW_EVENT_CREATE);
 236                 ++cit;
 237             }
 238             else // ( *cit > *oit )
 239             {
 240                 changedFiles.push_back(*oit);
 241                 changedFlags.push_back(wxFSW_EVENT_DELETE);
 242                 ++oit;
 243             }
 244         }
 245
 246         // border conditions
 247         if ( oit == old.files.end() )
 248         {
 249             for ( ; cit != curr.files.end(); ++cit )
 250             {
 251                 changedFiles.push_back( *cit );
 252                 changedFlags.push_back(wxFSW_EVENT_CREATE);
 253             }
 254         }
 255         else if ( cit == curr.files.end() )
 256         {
 257             for ( ; oit != old.files.end(); ++oit )
 258             {
 259                 changedFiles.push_back( *oit );
 260                 changedFlags.push_back(wxFSW_EVENT_DELETE);
 261             }
 262         }
 263
 264         wxASSERT( changedFiles.size() == changedFlags.size() );
 265
 266 #if 0
 267         wxLogTrace(wxTRACE_FSWATCHER, "Changed files:");
 268         wxArrayString::iterator it = changedFiles.begin();
 269         wxArrayInt::iterator it2 = changedFlags.begin();
 270         for ( ; it != changedFiles.end(); ++it, ++it2)
 271         {
 272             wxString action = (*it2 == wxFSW_EVENT_CREATE) ?
 273                                 "created" : "deleted";
 274             wxLogTrace(wxTRACE_FSWATCHER, wxString::Format("File: '%s' %s",
 275                         *it, action));
 276         }
 277 #endif
 278     }
 279
 280     void ProcessNativeEvent(const struct kevent& e)
 281     {
 282         wxASSERT_MSG(e.udata, "Null user data associated with kevent!");
 283
 284         wxLogTrace(wxTRACE_FSWATCHER, "Event: ident=%d, filter=%d, flags=%u, "
 285                    "fflags=%u, data=%d, user_data=%p",
 286                    e.ident, e.filter, e.flags, e.fflags, e.data, e.udata);
 287
 288         // for ease of use
 289         wxFSWatchEntryKq& w = *(static_cast<wxFSWatchEntry*>(e.udata));
 290         int nflags = e.fflags;
 291
 292         // clear ignored flags
 293         nflags &= ~NOTE_REVOKE;
 294
 295         // TODO ignore events we didn't ask for + refactor this cascade ifs
 296         // check for events
 297         while ( nflags )
 298         {
 299             // when monitoring dir, this means create/delete
 300             const wxString basepath = w.GetPath();
 301             if ( nflags & NOTE_WRITE && wxDirExists(basepath) )
 302             {
 303                 // NOTE_LINK is set when the dir was created, but we
 304                 // don't care - we look for new names in directory
 305                 // regardless of type. Also, clear all this, because
 306                 // it cannot mean more by itself
 307                 nflags &= ~(NOTE_WRITE | NOTE_ATTRIB | NOTE_LINK);
 308
 309                 wxArrayString changedFiles;
 310                 wxArrayInt changedFlags;
 311                 FindChanges(w, changedFiles, changedFlags);
 312
 313                 wxArrayString::iterator it = changedFiles.begin();
 314                 wxArrayInt::iterator changeType = changedFlags.begin();
 315                 for ( ; it != changedFiles.end(); ++it, ++changeType )
 316                 {
 317                     const wxString fullpath = w.GetPath() +
 318                                                 wxFileName::GetPathSeparator() +
 319                                                   *it;
 320                     const wxFileName path(wxDirExists(fullpath)
 321                                             ? wxFileName::DirName(fullpath)
 322                                             : wxFileName::FileName(fullpath));
 323
 324                     wxFileSystemWatcherEvent event(*changeType, path, path);
 325                     SendEvent(event);
 326                 }
 327             }
 328             else if ( nflags & NOTE_RENAME )
 329             {
 330                 // CHECK it'd be only possible to detect name if we had
 331                 // parent files listing which we could confront with now and
 332                 // still we couldn't be sure we have the right name...
 333                 nflags &= ~NOTE_RENAME;
 334                 wxFileSystemWatcherEvent event(wxFSW_EVENT_RENAME,
 335                                         basepath, wxFileName());
 336                 SendEvent(event);
 337             }
 338             else if ( nflags & NOTE_WRITE || nflags & NOTE_EXTEND )
 339             {
 340                 nflags &= ~(NOTE_WRITE | NOTE_EXTEND);
 341                 wxFileSystemWatcherEvent event(wxFSW_EVENT_MODIFY,
 342                                         basepath, basepath);
 343                 SendEvent(event);
 344             }
 345             else if ( nflags & NOTE_DELETE )
 346             {
 347                 nflags &= ~(NOTE_DELETE);
 348                 wxFileSystemWatcherEvent event(wxFSW_EVENT_DELETE,
 349                                         basepath, basepath);
 350                 SendEvent(event);
 351             }
 352             else if ( nflags & NOTE_ATTRIB )
 353             {
 354                 nflags &= ~(NOTE_ATTRIB);
 355                 wxFileSystemWatcherEvent event(wxFSW_EVENT_ACCESS,
 356                                         basepath, basepath);
 357                 SendEvent(event);
 358             }
 359
 360             // clear any flags that won't mean anything by themselves
 361             nflags &= ~(NOTE_LINK);
 362         }
 363     }
 364
 365     void SendEvent(wxFileSystemWatcherEvent& evt)
 366     {
 367         m_watcher->GetOwner()->ProcessEvent(evt);
 368     }
 369
 370     static int Watcher2NativeFlags(int WXUNUSED(flags))
 371     {
 372         // TODO: it would be better to only subscribe to what we need
 373         return NOTE_DELETE | NOTE_WRITE | NOTE_EXTEND |
 374                NOTE_ATTRIB | NOTE_LINK | NOTE_RENAME |
 375                NOTE_REVOKE;
 376     }
 377
 378     wxFSWSourceHandler* m_handler;        // handler for kqueue event source
 379     wxEventLoopSource* m_source;          // our event loop source
 380
 381     // descriptor created by kqueue()
 382     int m_kfd;
 383 };
 384
 385
 386 // once we get signaled to read, actuall event reading occurs
 387 void wxFSWSourceHandler::OnReadWaiting()
 388 {
 389     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 390     m_service->ReadEvents();
 391 }
 392
 393 void wxFSWSourceHandler::OnWriteWaiting()
 394 {
 395     wxFAIL_MSG("We never write to kqueue descriptor.");
 396 }
 397
 398 void wxFSWSourceHandler::OnExceptionWaiting()
 399 {
 400     wxFAIL_MSG("We never receive exceptions on kqueue descriptor.");
 401 }
 402
 403
 404 // ============================================================================
 405 // wxKqueueFileSystemWatcher implementation
 406 // ============================================================================
 407
 408 wxKqueueFileSystemWatcher::wxKqueueFileSystemWatcher()
 409     : wxFileSystemWatcherBase()
 410 {
 411     Init();
 412 }
 413
 414 wxKqueueFileSystemWatcher::wxKqueueFileSystemWatcher(const wxFileName& path,
 415                                                      int events)
 416     : wxFileSystemWatcherBase()
 417 {
 418     if (!Init())
 419     {
 420         wxDELETE(m_service);
 421         return;
 422     }
 423
 424     Add(path, events);
 425 }
 426
 427 wxKqueueFileSystemWatcher::~wxKqueueFileSystemWatcher()
 428 {
 429 }
 430
 431 bool wxKqueueFileSystemWatcher::Init()
 432 {
 433     m_service = new wxFSWatcherImplKqueue(this);
 434     return m_service->Init();
 435 }
 436
 437 #endif // wxHAS_KQUEUE
 438
 439 #endif // wxUSE_FSWATCHER