src/unix/fswatcher_inotify.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/unix/fswatcher_inotify.cpp
   3 // Purpose:     inotify-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_INOTIFY
  23
  24 #include <sys/inotify.h>
  25 #include <unistd.h>
  26 #include "wx/private/fswatcher.h"
  27
  28 // ============================================================================
  29 // wxFSWatcherImpl implementation & helper wxFSWSourceHandler implementation
  30 // ============================================================================
  31
  32 // inotify watch descriptor => wxFSWatchEntry* map
  33 WX_DECLARE_HASH_MAP(int, wxFSWatchEntry*, wxIntegerHash, wxIntegerEqual,
  34                                               wxFSWatchEntryDescriptors);
  35
  36 // inotify event cookie => inotify_event* map
  37 WX_DECLARE_HASH_MAP(int, inotify_event*, wxIntegerHash, wxIntegerEqual,
  38                                                       wxInotifyCookies);
  39
  40 /**
  41  * Helper class encapsulating inotify mechanism
  42  */
  43 class wxFSWatcherImplUnix : public wxFSWatcherImpl
  44 {
  45 public:
  46     wxFSWatcherImplUnix(wxFileSystemWatcherBase* watcher) :
  47         wxFSWatcherImpl(watcher),
  48         m_source(NULL),
  49         m_ifd(-1)
  50     {
  51         m_handler = new wxFSWSourceHandler(this);
  52     }
  53
  54     ~wxFSWatcherImplUnix()
  55     {
  56         // we close inotify only if initialized before
  57         if (IsOk())
  58         {
  59             Close();
  60         }
  61
  62         delete m_handler;
  63     }
  64
  65     bool Init()
  66     {
  67         wxCHECK_MSG( !IsOk(), false, "Inotify already initialized" );
  68
  69         wxEventLoopBase *loop = wxEventLoopBase::GetActive();
  70         wxCHECK_MSG( loop, false, "File system watcher needs an event loop" );
  71
  72         m_ifd = inotify_init();
  73         if ( m_ifd == -1 )
  74         {
  75             wxLogSysError( _("Unable to create inotify instance") );
  76             return false;
  77         }
  78
  79         m_source = loop->AddSourceForFD
  80                          (
  81                           m_ifd,
  82                           m_handler,
  83                           wxEVENT_SOURCE_INPUT | wxEVENT_SOURCE_EXCEPTION
  84                          );
  85
  86         return m_source != NULL;
  87     }
  88
  89     void Close()
  90     {
  91         wxCHECK_RET( IsOk(),
  92                     "Inotify not initialized or invalid inotify descriptor" );
  93
  94         wxDELETE(m_source);
  95
  96         if ( close(m_ifd) != 0 )
  97         {
  98             wxLogSysError( _("Unable to close inotify instance") );
  99         }
 100     }
 101
 102     virtual bool DoAdd(wxSharedPtr<wxFSWatchEntryUnix> watch)
 103     {
 104         wxCHECK_MSG( IsOk(), false,
 105                     "Inotify not initialized or invalid inotify descriptor" );
 106
 107         int wd = DoAddInotify(watch.get());
 108         if (wd == -1)
 109         {
 110             wxLogSysError( _("Unable to add inotify watch") );
 111             return false;
 112         }
 113
 114         wxFSWatchEntryDescriptors::value_type val(wd, watch.get());
 115         if (!m_watchMap.insert(val).second)
 116         {
 117             wxFAIL_MSG( wxString::Format( "Path %s is already watched",
 118                                            watch->GetPath()) );
 119             return false;
 120         }
 121
 122         return true;
 123     }
 124
 125     virtual bool DoRemove(wxSharedPtr<wxFSWatchEntryUnix> watch)
 126     {
 127         wxCHECK_MSG( IsOk(), false,
 128                     "Inotify not initialized or invalid inotify descriptor" );
 129
 130         int ret = DoRemoveInotify(watch.get());
 131         if (ret == -1)
 132         {
 133             wxLogSysError( _("Unable to remove inotify watch") );
 134             return false;
 135         }
 136
 137         if (m_watchMap.erase(watch->GetWatchDescriptor()) != 1)
 138         {
 139             wxFAIL_MSG( wxString::Format("Path %s is not watched",
 140                                           watch->GetPath()) );
 141         }
 142         watch->SetWatchDescriptor(-1);
 143         return true;
 144     }
 145
 146     virtual bool RemoveAll()
 147     {
 148         wxFSWatchEntries::iterator it = m_watches.begin();
 149         for ( ; it != m_watches.end(); ++it )
 150         {
 151             (void) DoRemove(it->second);
 152         }
 153         m_watches.clear();
 154         return true;
 155     }
 156
 157     int ReadEvents()
 158     {
 159         wxCHECK_MSG( IsOk(), -1,
 160                     "Inotify not initialized or invalid inotify descriptor" );
 161
 162         // read events
 163         // TODO differentiate depending on params
 164         char buf[128 * sizeof(inotify_event)];
 165         int left = ReadEventsToBuf(buf, sizeof(buf));
 166         if (left == -1)
 167             return -1;
 168
 169         // left > 0, we have events
 170         char* memory = buf;
 171         int event_count = 0;
 172         while (left > 0) // OPT checking 'memory' would suffice
 173         {
 174             event_count++;
 175             inotify_event* e = (inotify_event*)memory;
 176
 177             // process one inotify_event
 178             ProcessNativeEvent(*e);
 179
 180             int offset = sizeof(inotify_event) + e->len;
 181             left -= offset;
 182             memory += offset;
 183         }
 184
 185         // take care of unmatched renames
 186         ProcessRenames();
 187
 188         wxLogTrace(wxTRACE_FSWATCHER, "We had %d native events", event_count);
 189         return event_count;
 190     }
 191
 192     bool IsOk() const
 193     {
 194         return m_source != NULL;
 195     }
 196
 197 protected:
 198     int DoAddInotify(wxFSWatchEntry* watch)
 199     {
 200         int flags = Watcher2NativeFlags(watch->GetFlags());
 201         int wd = inotify_add_watch(m_ifd, watch->GetPath().fn_str(), flags);
 202         // finally we can set watch descriptor
 203         watch->SetWatchDescriptor(wd);
 204         return wd;
 205     }
 206
 207     int DoRemoveInotify(wxFSWatchEntry* watch)
 208     {
 209         return inotify_rm_watch(m_ifd, watch->GetWatchDescriptor());
 210     }
 211
 212     void ProcessNativeEvent(const inotify_event& inevt)
 213     {
 214         wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 215
 216         // after removing inotify watch we get IN_IGNORED for it, but the watch
 217         // will be already removed from our list at that time
 218         if (inevt.mask & IN_IGNORED)
 219         {
 220             return;
 221         }
 222
 223         // get watch entry for this event
 224         wxFSWatchEntryDescriptors::iterator it = m_watchMap.find(inevt.wd);
 225         wxCHECK_RET(it != m_watchMap.end(),
 226                              "Watch descriptor not present in the watch map!");
 227
 228         wxFSWatchEntry& watch = *(it->second);
 229         int nativeFlags = inevt.mask;
 230         int flags = Native2WatcherFlags(nativeFlags);
 231
 232         // check out for error/warning condition
 233         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 234         {
 235             wxString errMsg = GetErrorDescription(Watcher2NativeFlags(flags));
 236             wxFileSystemWatcherEvent event(flags, errMsg);
 237             SendEvent(event);
 238         }
 239         // filter out ignored events and those not asked for.
 240         // we never filter out warnings or exceptions
 241         else if ((flags == 0) || !(flags & watch.GetFlags()))
 242         {
 243             return;
 244         }
 245         // renames
 246         else if (nativeFlags & IN_MOVE)
 247         {
 248             wxInotifyCookies::iterator it = m_cookies.find(inevt.cookie);
 249             if ( it == m_cookies.end() )
 250             {
 251                 int size = sizeof(inevt) + inevt.len;
 252                 inotify_event* e = (inotify_event*) operator new (size);
 253                 memcpy(e, &inevt, size);
 254
 255                 wxInotifyCookies::value_type val(e->cookie, e);
 256                 m_cookies.insert(val);
 257             }
 258             else
 259             {
 260                 inotify_event& oldinevt = *(it->second);
 261
 262                 wxFileSystemWatcherEvent event(flags);
 263                 if ( inevt.mask & IN_MOVED_FROM )
 264                 {
 265                     event.SetPath(GetEventPath(watch, inevt));
 266                     event.SetNewPath(GetEventPath(watch, oldinevt));
 267                 }
 268                 else
 269                 {
 270                     event.SetPath(GetEventPath(watch, oldinevt));
 271                     event.SetNewPath(GetEventPath(watch, inevt));
 272                 }
 273                 SendEvent(event);
 274
 275                 m_cookies.erase(it);
 276                 delete &oldinevt;
 277             }
 278         }
 279         // every other kind of event
 280         else
 281         {
 282             wxFileName path = GetEventPath(watch, inevt);
 283             wxFileSystemWatcherEvent event(flags, path, path);
 284             SendEvent(event);
 285         }
 286     }
 287
 288     void ProcessRenames()
 289     {
 290         wxInotifyCookies::iterator it = m_cookies.begin();
 291         while ( it != m_cookies.end() )
 292         {
 293             inotify_event& inevt = *(it->second);
 294
 295             wxLogTrace(wxTRACE_FSWATCHER, "Processing pending rename events");
 296             wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 297
 298             // get watch entry for this event
 299             wxFSWatchEntryDescriptors::iterator wit = m_watchMap.find(inevt.wd);
 300             wxCHECK_RET(wit != m_watchMap.end(),
 301                              "Watch descriptor not present in the watch map!");
 302
 303             wxFSWatchEntry& watch = *(wit->second);
 304             int flags = Native2WatcherFlags(inevt.mask);
 305             wxFileName path = GetEventPath(watch, inevt);
 306             wxFileSystemWatcherEvent event(flags, path, path);
 307             SendEvent(event);
 308
 309             m_cookies.erase(it);
 310             delete &inevt;
 311             it = m_cookies.begin();
 312         }
 313     }
 314
 315     void SendEvent(wxFileSystemWatcherEvent& evt)
 316     {
 317         wxLogTrace(wxTRACE_FSWATCHER, evt.ToString());
 318         m_watcher->GetOwner()->ProcessEvent(evt);
 319     }
 320
 321     int ReadEventsToBuf(char* buf, int size)
 322     {
 323         wxCHECK_MSG( IsOk(), false,
 324                     "Inotify not initialized or invalid inotify descriptor" );
 325
 326         memset(buf, 0, size);
 327         ssize_t left = read(m_ifd, buf, size);
 328         if (left == -1)
 329         {
 330             wxLogSysError(_("Unable to read from inotify descriptor"));
 331             return -1;
 332         }
 333         else if (left == 0)
 334         {
 335             wxLogWarning(_("EOF while reading from inotify descriptor"));
 336             return -1;
 337         }
 338
 339         return left;
 340     }
 341
 342     static wxString InotifyEventToString(const inotify_event& inevt)
 343     {
 344         wxString mask = (inevt.mask & IN_ISDIR) ?
 345                         wxString::Format("IS_DIR | %u", inevt.mask & ~IN_ISDIR) :
 346                         wxString::Format("%u", inevt.mask);
 347         return wxString::Format("Event: wd=%d, mask=%s, cookie=%u, len=%u, "
 348                                 "name=%s", inevt.wd, mask, inevt.cookie,
 349                                 inevt.len, inevt.name);
 350     }
 351
 352     static wxFileName GetEventPath(const wxFSWatchEntry& watch,
 353                                    const inotify_event& inevt)
 354     {
 355         // only when dir is watched, we have non-empty e.name
 356         wxFileName path = watch.GetPath();
 357         if (path.IsDir())
 358         {
 359             path = wxFileName(path.GetPath(), inevt.name);
 360         }
 361         return path;
 362     }
 363
 364     static int Watcher2NativeFlags(int WXUNUSED(flags))
 365     {
 366         // TODO: it would be nice to subscribe only to the events we really need
 367         return IN_ALL_EVENTS;
 368     }
 369
 370     static int Native2WatcherFlags(int flags)
 371     {
 372         static const int flag_mapping[][2] = {
 373             { IN_ACCESS,        wxFSW_EVENT_ACCESS }, // generated during read!
 374             { IN_MODIFY,        wxFSW_EVENT_MODIFY },
 375             { IN_ATTRIB,        0 },
 376             { IN_CLOSE_WRITE,   0 },
 377             { IN_CLOSE_NOWRITE, 0 },
 378             { IN_OPEN,          0 },
 379             { IN_MOVED_FROM,    wxFSW_EVENT_RENAME },
 380             { IN_MOVED_TO,      wxFSW_EVENT_RENAME },
 381             { IN_CREATE,        wxFSW_EVENT_CREATE },
 382             { IN_DELETE,        wxFSW_EVENT_DELETE },
 383             { IN_DELETE_SELF,   wxFSW_EVENT_DELETE },
 384             { IN_MOVE_SELF,     wxFSW_EVENT_DELETE },
 385
 386             { IN_UNMOUNT,       wxFSW_EVENT_ERROR  },
 387             { IN_Q_OVERFLOW,    wxFSW_EVENT_WARNING},
 388
 389             // ignored, because this is genereted mainly by watcher::Remove()
 390             { IN_IGNORED,        0 }
 391         };
 392
 393         unsigned int i=0;
 394         for ( ; i < WXSIZEOF(flag_mapping); ++i) {
 395             // in this mapping multiple flags at once don't happen
 396             if (flags & flag_mapping[i][0])
 397                 return flag_mapping[i][1];
 398         }
 399
 400         // never reached
 401         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flags));
 402         return -1;
 403     }
 404
 405     /**
 406      * Returns error description for specified inotify mask
 407      */
 408     static const wxString GetErrorDescription(int flag)
 409     {
 410         switch ( flag )
 411         {
 412         case IN_UNMOUNT:
 413             return _("File system containing watched object was unmounted");
 414         case IN_Q_OVERFLOW:
 415             return _("Event queue overflowed");
 416         }
 417
 418         // never reached
 419         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flag));
 420         return wxEmptyString;
 421     }
 422
 423     wxFSWSourceHandler* m_handler;        // handler for inotify event source
 424     wxFSWatchEntryDescriptors m_watchMap; // inotify wd=>wxFSWatchEntry* map
 425     wxInotifyCookies m_cookies;           // map to track renames
 426     wxEventLoopSource* m_source;          // our event loop source
 427
 428     // file descriptor created by inotify_init()
 429     int m_ifd;
 430 };
 431
 432
 433 // ============================================================================
 434 // wxFSWSourceHandler implementation
 435 // ============================================================================
 436
 437 // once we get signaled to read, actuall event reading occurs
 438 void wxFSWSourceHandler::OnReadWaiting()
 439 {
 440     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 441     m_service->ReadEvents();
 442 }
 443
 444 void wxFSWSourceHandler::OnWriteWaiting()
 445 {
 446     wxFAIL_MSG("We never write to inotify descriptor.");
 447 }
 448
 449 void wxFSWSourceHandler::OnExceptionWaiting()
 450 {
 451     wxFAIL_MSG("We never receive exceptions on inotify descriptor.");
 452 }
 453
 454
 455 // ============================================================================
 456 // wxInotifyFileSystemWatcher implementation
 457 // ============================================================================
 458
 459 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher()
 460     : wxFileSystemWatcherBase()
 461 {
 462     Init();
 463 }
 464
 465 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher(const wxFileName& path,
 466                                                        int events)
 467     : wxFileSystemWatcherBase()
 468 {
 469     if (!Init())
 470     {
 471         if (m_service)
 472             delete m_service;
 473         return;
 474     }
 475
 476     Add(path, events);
 477 }
 478
 479 wxInotifyFileSystemWatcher::~wxInotifyFileSystemWatcher()
 480 {
 481 }
 482
 483 bool wxInotifyFileSystemWatcher::Init()
 484 {
 485     m_service = new wxFSWatcherImplUnix(this);
 486     return m_service->Init();
 487 }
 488
 489 #endif // wxHAS_INOTIFY
 490
 491 #endif // wxUSE_FSWATCHER