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         // Cache the wd in case any events arrive late
 143         m_staleDescriptors.Add(watch->GetWatchDescriptor());
 144
 145         watch->SetWatchDescriptor(-1);
 146         return true;
 147     }
 148
 149     virtual bool RemoveAll()
 150     {
 151         wxFSWatchEntries::iterator it = m_watches.begin();
 152         for ( ; it != m_watches.end(); ++it )
 153         {
 154             (void) DoRemove(it->second);
 155         }
 156         m_watches.clear();
 157         return true;
 158     }
 159
 160     int ReadEvents()
 161     {
 162         wxCHECK_MSG( IsOk(), -1,
 163                     "Inotify not initialized or invalid inotify descriptor" );
 164
 165         // read events
 166         // TODO differentiate depending on params
 167         char buf[128 * sizeof(inotify_event)];
 168         int left = ReadEventsToBuf(buf, sizeof(buf));
 169         if (left == -1)
 170             return -1;
 171
 172         // left > 0, we have events
 173         char* memory = buf;
 174         int event_count = 0;
 175         while (left > 0) // OPT checking 'memory' would suffice
 176         {
 177             event_count++;
 178             inotify_event* e = (inotify_event*)memory;
 179
 180             // process one inotify_event
 181             ProcessNativeEvent(*e);
 182
 183             int offset = sizeof(inotify_event) + e->len;
 184             left -= offset;
 185             memory += offset;
 186         }
 187
 188         // take care of unmatched renames
 189         ProcessRenames();
 190
 191         wxLogTrace(wxTRACE_FSWATCHER, "We had %d native events", event_count);
 192         return event_count;
 193     }
 194
 195     bool IsOk() const
 196     {
 197         return m_source != NULL;
 198     }
 199
 200 protected:
 201     int DoAddInotify(wxFSWatchEntry* watch)
 202     {
 203         int flags = Watcher2NativeFlags(watch->GetFlags());
 204         int wd = inotify_add_watch(m_ifd, watch->GetPath().fn_str(), flags);
 205         // finally we can set watch descriptor
 206         watch->SetWatchDescriptor(wd);
 207         return wd;
 208     }
 209
 210     int DoRemoveInotify(wxFSWatchEntry* watch)
 211     {
 212         return inotify_rm_watch(m_ifd, watch->GetWatchDescriptor());
 213     }
 214
 215     void ProcessNativeEvent(const inotify_event& inevt)
 216     {
 217         wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 218
 219         // after removing inotify watch we get IN_IGNORED for it, but the watch
 220         // will be already removed from our list at that time
 221         if (inevt.mask & IN_IGNORED)
 222         {
 223             // It is now safe to remove it from the stale descriptors too, we
 224             // won't get any more events for it.
 225             m_staleDescriptors.Remove(inevt.wd);
 226             wxLogTrace(wxTRACE_FSWATCHER,
 227                        "Removed wd %i from the stale-wd cache", inevt.wd);
 228             return;
 229         }
 230
 231         // get watch entry for this event
 232         wxFSWatchEntryDescriptors::iterator it = m_watchMap.find(inevt.wd);
 233         if (it == m_watchMap.end())
 234         {
 235             // It's not in the map; check if was recently removed from it.
 236             if (m_staleDescriptors.Index(inevt.wd) != wxNOT_FOUND)
 237             {
 238                 wxLogTrace(wxTRACE_FSWATCHER,
 239                            "Got an event for stale wd %i", inevt.wd);
 240             }
 241             else
 242             {
 243                 wxFAIL_MSG("Event for unknown watch descriptor.");
 244             }
 245
 246             // In any case, don't process this event: it's either for an
 247             // already removed entry, or for a completely unknown one.
 248             return;
 249         }
 250
 251         wxFSWatchEntry& watch = *(it->second);
 252         int nativeFlags = inevt.mask;
 253         int flags = Native2WatcherFlags(nativeFlags);
 254
 255         // check out for error/warning condition
 256         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 257         {
 258             wxString errMsg = GetErrorDescription(Watcher2NativeFlags(flags));
 259             wxFileSystemWatcherEvent event(flags, errMsg);
 260             SendEvent(event);
 261         }
 262         // filter out ignored events and those not asked for.
 263         // we never filter out warnings or exceptions
 264         else if ((flags == 0) || !(flags & watch.GetFlags()))
 265         {
 266             return;
 267         }
 268         // renames
 269         else if (nativeFlags & IN_MOVE)
 270         {
 271             wxInotifyCookies::iterator it = m_cookies.find(inevt.cookie);
 272             if ( it == m_cookies.end() )
 273             {
 274                 int size = sizeof(inevt) + inevt.len;
 275                 inotify_event* e = (inotify_event*) operator new (size);
 276                 memcpy(e, &inevt, size);
 277
 278                 wxInotifyCookies::value_type val(e->cookie, e);
 279                 m_cookies.insert(val);
 280             }
 281             else
 282             {
 283                 inotify_event& oldinevt = *(it->second);
 284
 285                 wxFileSystemWatcherEvent event(flags);
 286                 if ( inevt.mask & IN_MOVED_FROM )
 287                 {
 288                     event.SetPath(GetEventPath(watch, inevt));
 289                     event.SetNewPath(GetEventPath(watch, oldinevt));
 290                 }
 291                 else
 292                 {
 293                     event.SetPath(GetEventPath(watch, oldinevt));
 294                     event.SetNewPath(GetEventPath(watch, inevt));
 295                 }
 296                 SendEvent(event);
 297
 298                 m_cookies.erase(it);
 299                 delete &oldinevt;
 300             }
 301         }
 302         // every other kind of event
 303         else
 304         {
 305             wxFileName path = GetEventPath(watch, inevt);
 306             wxFileSystemWatcherEvent event(flags, path, path);
 307             SendEvent(event);
 308         }
 309     }
 310
 311     void ProcessRenames()
 312     {
 313         wxInotifyCookies::iterator it = m_cookies.begin();
 314         while ( it != m_cookies.end() )
 315         {
 316             inotify_event& inevt = *(it->second);
 317
 318             wxLogTrace(wxTRACE_FSWATCHER, "Processing pending rename events");
 319             wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 320
 321             // get watch entry for this event
 322             wxFSWatchEntryDescriptors::iterator wit = m_watchMap.find(inevt.wd);
 323             wxCHECK_RET(wit != m_watchMap.end(),
 324                              "Watch descriptor not present in the watch map!");
 325
 326             wxFSWatchEntry& watch = *(wit->second);
 327             int flags = Native2WatcherFlags(inevt.mask);
 328             wxFileName path = GetEventPath(watch, inevt);
 329             wxFileSystemWatcherEvent event(flags, path, path);
 330             SendEvent(event);
 331
 332             m_cookies.erase(it);
 333             delete &inevt;
 334             it = m_cookies.begin();
 335         }
 336     }
 337
 338     void SendEvent(wxFileSystemWatcherEvent& evt)
 339     {
 340         wxLogTrace(wxTRACE_FSWATCHER, evt.ToString());
 341         m_watcher->GetOwner()->ProcessEvent(evt);
 342     }
 343
 344     int ReadEventsToBuf(char* buf, int size)
 345     {
 346         wxCHECK_MSG( IsOk(), false,
 347                     "Inotify not initialized or invalid inotify descriptor" );
 348
 349         memset(buf, 0, size);
 350         ssize_t left = read(m_ifd, buf, size);
 351         if (left == -1)
 352         {
 353             wxLogSysError(_("Unable to read from inotify descriptor"));
 354             return -1;
 355         }
 356         else if (left == 0)
 357         {
 358             wxLogWarning(_("EOF while reading from inotify descriptor"));
 359             return -1;
 360         }
 361
 362         return left;
 363     }
 364
 365     static wxString InotifyEventToString(const inotify_event& inevt)
 366     {
 367         wxString mask = (inevt.mask & IN_ISDIR) ?
 368                         wxString::Format("IS_DIR | %u", inevt.mask & ~IN_ISDIR) :
 369                         wxString::Format("%u", inevt.mask);
 370         const char* name = "";
 371         if (inevt.len)
 372             name = inevt.name;
 373         return wxString::Format("Event: wd=%d, mask=%s, cookie=%u, len=%u, "
 374                                 "name=%s", inevt.wd, mask, inevt.cookie,
 375                                 inevt.len, name);
 376     }
 377
 378     static wxFileName GetEventPath(const wxFSWatchEntry& watch,
 379                                    const inotify_event& inevt)
 380     {
 381         // only when dir is watched, we have non-empty e.name
 382         wxFileName path = watch.GetPath();
 383         if (path.IsDir() && inevt.len)
 384         {
 385             path = wxFileName(path.GetPath(), inevt.name);
 386         }
 387         return path;
 388     }
 389
 390     static int Watcher2NativeFlags(int WXUNUSED(flags))
 391     {
 392         // TODO: it would be nice to subscribe only to the events we really need
 393         return IN_ALL_EVENTS;
 394     }
 395
 396     static int Native2WatcherFlags(int flags)
 397     {
 398         static const int flag_mapping[][2] = {
 399             { IN_ACCESS,        wxFSW_EVENT_ACCESS }, // generated during read!
 400             { IN_MODIFY,        wxFSW_EVENT_MODIFY },
 401             { IN_ATTRIB,        0 },
 402             { IN_CLOSE_WRITE,   0 },
 403             { IN_CLOSE_NOWRITE, 0 },
 404             { IN_OPEN,          0 },
 405             { IN_MOVED_FROM,    wxFSW_EVENT_RENAME },
 406             { IN_MOVED_TO,      wxFSW_EVENT_RENAME },
 407             { IN_CREATE,        wxFSW_EVENT_CREATE },
 408             { IN_DELETE,        wxFSW_EVENT_DELETE },
 409             { IN_DELETE_SELF,   wxFSW_EVENT_DELETE },
 410             { IN_MOVE_SELF,     wxFSW_EVENT_DELETE },
 411
 412             { IN_UNMOUNT,       wxFSW_EVENT_ERROR  },
 413             { IN_Q_OVERFLOW,    wxFSW_EVENT_WARNING},
 414
 415             // ignored, because this is genereted mainly by watcher::Remove()
 416             { IN_IGNORED,        0 }
 417         };
 418
 419         unsigned int i=0;
 420         for ( ; i < WXSIZEOF(flag_mapping); ++i) {
 421             // in this mapping multiple flags at once don't happen
 422             if (flags & flag_mapping[i][0])
 423                 return flag_mapping[i][1];
 424         }
 425
 426         // never reached
 427         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flags));
 428         return -1;
 429     }
 430
 431     /**
 432      * Returns error description for specified inotify mask
 433      */
 434     static const wxString GetErrorDescription(int flag)
 435     {
 436         switch ( flag )
 437         {
 438         case IN_UNMOUNT:
 439             return _("File system containing watched object was unmounted");
 440         case IN_Q_OVERFLOW:
 441             return _("Event queue overflowed");
 442         }
 443
 444         // never reached
 445         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flag));
 446         return wxEmptyString;
 447     }
 448
 449     wxFSWSourceHandler* m_handler;        // handler for inotify event source
 450     wxFSWatchEntryDescriptors m_watchMap; // inotify wd=>wxFSWatchEntry* map
 451     wxArrayInt m_staleDescriptors;        // stores recently-removed watches
 452     wxInotifyCookies m_cookies;           // map to track renames
 453     wxEventLoopSource* m_source;          // our event loop source
 454
 455     // file descriptor created by inotify_init()
 456     int m_ifd;
 457 };
 458
 459
 460 // ============================================================================
 461 // wxFSWSourceHandler implementation
 462 // ============================================================================
 463
 464 // once we get signaled to read, actuall event reading occurs
 465 void wxFSWSourceHandler::OnReadWaiting()
 466 {
 467     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 468     m_service->ReadEvents();
 469 }
 470
 471 void wxFSWSourceHandler::OnWriteWaiting()
 472 {
 473     wxFAIL_MSG("We never write to inotify descriptor.");
 474 }
 475
 476 void wxFSWSourceHandler::OnExceptionWaiting()
 477 {
 478     wxFAIL_MSG("We never receive exceptions on inotify descriptor.");
 479 }
 480
 481
 482 // ============================================================================
 483 // wxInotifyFileSystemWatcher implementation
 484 // ============================================================================
 485
 486 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher()
 487     : wxFileSystemWatcherBase()
 488 {
 489     Init();
 490 }
 491
 492 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher(const wxFileName& path,
 493                                                        int events)
 494     : wxFileSystemWatcherBase()
 495 {
 496     if (!Init())
 497     {
 498         if (m_service)
 499             delete m_service;
 500         return;
 501     }
 502
 503     Add(path, events);
 504 }
 505
 506 wxInotifyFileSystemWatcher::~wxInotifyFileSystemWatcher()
 507 {
 508 }
 509
 510 bool wxInotifyFileSystemWatcher::Init()
 511 {
 512     m_service = new wxFSWatcherImplUnix(this);
 513     return m_service->Init();
 514 }
 515
 516 #endif // wxHAS_INOTIFY
 517
 518 #endif // wxUSE_FSWATCHER