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             // However if we're here because a dir that we're still watching
 226             // has just been deleted, its wd won't be on this list
 227             const int pos = m_staleDescriptors.Index(inevt.wd);
 228             if ( pos != wxNOT_FOUND )
 229             {
 230                 m_staleDescriptors.RemoveAt(static_cast<size_t>(pos));
 231                 wxLogTrace(wxTRACE_FSWATCHER,
 232                        "Removed wd %i from the stale-wd cache", inevt.wd);
 233             }
 234             return;
 235         }
 236
 237         // get watch entry for this event
 238         wxFSWatchEntryDescriptors::iterator it = m_watchMap.find(inevt.wd);
 239         if (it == m_watchMap.end())
 240         {
 241             // It's not in the map; check if was recently removed from it.
 242             if (m_staleDescriptors.Index(inevt.wd) != wxNOT_FOUND)
 243             {
 244                 wxLogTrace(wxTRACE_FSWATCHER,
 245                            "Got an event for stale wd %i", inevt.wd);
 246             }
 247             else
 248             {
 249                 wxFAIL_MSG("Event for unknown watch descriptor.");
 250             }
 251
 252             // In any case, don't process this event: it's either for an
 253             // already removed entry, or for a completely unknown one.
 254             return;
 255         }
 256
 257         wxFSWatchEntry& watch = *(it->second);
 258         int nativeFlags = inevt.mask;
 259         int flags = Native2WatcherFlags(nativeFlags);
 260
 261         // check out for error/warning condition
 262         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 263         {
 264             wxString errMsg = GetErrorDescription(Watcher2NativeFlags(flags));
 265             wxFileSystemWatcherEvent event(flags, errMsg);
 266             SendEvent(event);
 267         }
 268         // filter out ignored events and those not asked for.
 269         // we never filter out warnings or exceptions
 270         else if ((flags == 0) || !(flags & watch.GetFlags()))
 271         {
 272             return;
 273         }
 274
 275         // Creation
 276         // We need do something here only if the original watch was recursive;
 277         // we don't watch a child dir itself inside a non-tree watch.
 278         // We watch only dirs explicitly, so we don't want file IN_CREATEs.
 279         // Distinguish by whether nativeFlags contain IN_ISDIR
 280         else if ((nativeFlags & IN_CREATE) &&
 281                  (watch.GetType() == wxFSWPath_Tree) && (inevt.mask & IN_ISDIR))
 282         {
 283             wxFileName fn = GetEventPath(watch, inevt);
 284             // Though it's a dir, fn treats it as a file. So:
 285             fn.AssignDir(fn.GetFullPath());
 286
 287             if (m_watcher->AddAny(fn, wxFSW_EVENT_ALL,
 288                                    wxFSWPath_Tree, watch.GetFilespec()))
 289             {
 290                 // Tell the owner, in case it's interested
 291                 // If there's a filespec, assume he's not
 292                 if (watch.GetFilespec().empty())
 293                 {
 294                     wxFileSystemWatcherEvent event(flags, fn, fn);
 295                     SendEvent(event);
 296                 }
 297             }
 298         }
 299
 300         // Deletion
 301         // We watch only dirs explicitly, so we don't want file IN_DELETEs.
 302         // We obviously can't check using DirExists() as the object has been
 303         // deleted; and nativeFlags here doesn't contain IN_ISDIR, even for
 304         // a dir. Fortunately IN_DELETE_SELF doesn't happen for files. We need
 305         // to do something here only inside a tree watch, or if it's the parent
 306         // dir that's deleted. Otherwise let the parent dir cope
 307         else if ((nativeFlags & IN_DELETE_SELF) &&
 308                     ((watch.GetType() == wxFSWPath_Dir) ||
 309                      (watch.GetType() == wxFSWPath_Tree)))
 310         {
 311             // We must remove the deleted directory from the map, so that
 312             // DoRemoveInotify() isn't called on it in the future. Don't assert
 313             // if the wd isn't found: repeated IN_DELETE_SELFs can occur
 314             wxFileName fn = GetEventPath(watch, inevt);
 315             wxString path(fn.GetPathWithSep());
 316
 317             if (m_watchMap.erase(inevt.wd) == 1)
 318             {
 319                 // Delete from wxFileSystemWatcher
 320                 wxDynamicCast(m_watcher, wxInotifyFileSystemWatcher)->
 321                                             OnDirDeleted(path);
 322
 323                 // Now remove from our local list of watched items
 324                 wxFSWatchEntries::iterator wit =
 325                                         m_watches.find(path);
 326                 if (wit != m_watches.end())
 327                 {
 328                     m_watches.erase(wit);
 329                 }
 330
 331                 // Cache the wd in case any events arrive late
 332                 m_staleDescriptors.Add(inevt.wd);
 333             }
 334
 335             // Tell the owner, in case it's interested
 336             // If there's a filespec, assume he's not
 337             if (watch.GetFilespec().empty())
 338             {
 339                 wxFileSystemWatcherEvent event(flags, fn, fn);
 340                 SendEvent(event);
 341             }
 342         }
 343
 344         // renames
 345         else if (nativeFlags & IN_MOVE)
 346         {
 347             wxInotifyCookies::iterator it2 = m_cookies.find(inevt.cookie);
 348             if ( it2 == m_cookies.end() )
 349             {
 350                 int size = sizeof(inevt) + inevt.len;
 351                 inotify_event* e = (inotify_event*) operator new (size);
 352                 memcpy(e, &inevt, size);
 353
 354                 wxInotifyCookies::value_type val(e->cookie, e);
 355                 m_cookies.insert(val);
 356             }
 357             else
 358             {
 359                 inotify_event& oldinevt = *(it2->second);
 360
 361                 // Tell the owner, in case it's interested
 362                 // If there's a filespec, assume he's not
 363                 if ( watch.GetFilespec().empty() )
 364                 {
 365                     wxFileSystemWatcherEvent event(flags);
 366                     if ( inevt.mask & IN_MOVED_FROM )
 367                     {
 368                         event.SetPath(GetEventPath(watch, inevt));
 369                         event.SetNewPath(GetEventPath(watch, oldinevt));
 370                     }
 371                     else
 372                     {
 373                         event.SetPath(GetEventPath(watch, oldinevt));
 374                         event.SetNewPath(GetEventPath(watch, inevt));
 375                     }
 376                     SendEvent(event);
 377                 }
 378
 379                 m_cookies.erase(it2);
 380                 delete &oldinevt;
 381             }
 382         }
 383         // every other kind of event
 384         else
 385         {
 386             wxFileName path = GetEventPath(watch, inevt);
 387             // For files, check that it matches any filespec
 388             if ( MatchesFilespec(path, watch.GetFilespec()) )
 389             {
 390                 wxFileSystemWatcherEvent event(flags, path, path);
 391                 SendEvent(event);
 392             }
 393         }
 394     }
 395
 396     void ProcessRenames()
 397     {
 398         wxInotifyCookies::iterator it = m_cookies.begin();
 399         while ( it != m_cookies.end() )
 400         {
 401             inotify_event& inevt = *(it->second);
 402
 403             wxLogTrace(wxTRACE_FSWATCHER, "Processing pending rename events");
 404             wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 405
 406             // get watch entry for this event
 407             wxFSWatchEntryDescriptors::iterator wit = m_watchMap.find(inevt.wd);
 408             wxCHECK_RET(wit != m_watchMap.end(),
 409                              "Watch descriptor not present in the watch map!");
 410
 411             // Tell the owner, in case it's interested
 412             // If there's a filespec, assume he's not
 413             wxFSWatchEntry& watch = *(wit->second);
 414             if ( watch.GetFilespec().empty() )
 415             {
 416                 int flags = Native2WatcherFlags(inevt.mask);
 417                 wxFileName path = GetEventPath(watch, inevt);
 418                 {
 419                     wxFileSystemWatcherEvent event(flags, path, path);
 420                     SendEvent(event);
 421                 }
 422             }
 423
 424             m_cookies.erase(it);
 425             delete &inevt;
 426             it = m_cookies.begin();
 427         }
 428     }
 429
 430     void SendEvent(wxFileSystemWatcherEvent& evt)
 431     {
 432         wxLogTrace(wxTRACE_FSWATCHER, evt.ToString());
 433         m_watcher->GetOwner()->ProcessEvent(evt);
 434     }
 435
 436     int ReadEventsToBuf(char* buf, int size)
 437     {
 438         wxCHECK_MSG( IsOk(), false,
 439                     "Inotify not initialized or invalid inotify descriptor" );
 440
 441         memset(buf, 0, size);
 442         ssize_t left = read(m_ifd, buf, size);
 443         if (left == -1)
 444         {
 445             wxLogSysError(_("Unable to read from inotify descriptor"));
 446             return -1;
 447         }
 448         else if (left == 0)
 449         {
 450             wxLogWarning(_("EOF while reading from inotify descriptor"));
 451             return -1;
 452         }
 453
 454         return left;
 455     }
 456
 457     static wxString InotifyEventToString(const inotify_event& inevt)
 458     {
 459         wxString mask = (inevt.mask & IN_ISDIR) ?
 460                         wxString::Format("IS_DIR | %u", inevt.mask & ~IN_ISDIR) :
 461                         wxString::Format("%u", inevt.mask);
 462         const char* name = "";
 463         if (inevt.len)
 464             name = inevt.name;
 465         return wxString::Format("Event: wd=%d, mask=%s, cookie=%u, len=%u, "
 466                                 "name=%s", inevt.wd, mask, inevt.cookie,
 467                                 inevt.len, name);
 468     }
 469
 470     static wxFileName GetEventPath(const wxFSWatchEntry& watch,
 471                                    const inotify_event& inevt)
 472     {
 473         // only when dir is watched, we have non-empty e.name
 474         wxFileName path = watch.GetPath();
 475         if (path.IsDir() && inevt.len)
 476         {
 477             path = wxFileName(path.GetPath(), inevt.name);
 478         }
 479         return path;
 480     }
 481
 482     static int Watcher2NativeFlags(int WXUNUSED(flags))
 483     {
 484         // TODO: it would be nice to subscribe only to the events we really need
 485         return IN_ALL_EVENTS;
 486     }
 487
 488     static int Native2WatcherFlags(int flags)
 489     {
 490         static const int flag_mapping[][2] = {
 491             { IN_ACCESS,        wxFSW_EVENT_ACCESS }, // generated during read!
 492             { IN_MODIFY,        wxFSW_EVENT_MODIFY },
 493             { IN_ATTRIB,        0 },
 494             { IN_CLOSE_WRITE,   0 },
 495             { IN_CLOSE_NOWRITE, 0 },
 496             { IN_OPEN,          0 },
 497             { IN_MOVED_FROM,    wxFSW_EVENT_RENAME },
 498             { IN_MOVED_TO,      wxFSW_EVENT_RENAME },
 499             { IN_CREATE,        wxFSW_EVENT_CREATE },
 500             { IN_DELETE,        wxFSW_EVENT_DELETE },
 501             { IN_DELETE_SELF,   wxFSW_EVENT_DELETE },
 502             { IN_MOVE_SELF,     wxFSW_EVENT_DELETE },
 503
 504             { IN_UNMOUNT,       wxFSW_EVENT_ERROR  },
 505             { IN_Q_OVERFLOW,    wxFSW_EVENT_WARNING},
 506
 507             // ignored, because this is genereted mainly by watcher::Remove()
 508             { IN_IGNORED,        0 }
 509         };
 510
 511         unsigned int i=0;
 512         for ( ; i < WXSIZEOF(flag_mapping); ++i) {
 513             // in this mapping multiple flags at once don't happen
 514             if (flags & flag_mapping[i][0])
 515                 return flag_mapping[i][1];
 516         }
 517
 518         // never reached
 519         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flags));
 520         return -1;
 521     }
 522
 523     /**
 524      * Returns error description for specified inotify mask
 525      */
 526     static const wxString GetErrorDescription(int flag)
 527     {
 528         switch ( flag )
 529         {
 530         case IN_UNMOUNT:
 531             return _("File system containing watched object was unmounted");
 532         case IN_Q_OVERFLOW:
 533             return _("Event queue overflowed");
 534         }
 535
 536         // never reached
 537         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flag));
 538         return wxEmptyString;
 539     }
 540
 541     wxFSWSourceHandler* m_handler;        // handler for inotify event source
 542     wxFSWatchEntryDescriptors m_watchMap; // inotify wd=>wxFSWatchEntry* map
 543     wxArrayInt m_staleDescriptors;        // stores recently-removed watches
 544     wxInotifyCookies m_cookies;           // map to track renames
 545     wxEventLoopSource* m_source;          // our event loop source
 546
 547     // file descriptor created by inotify_init()
 548     int m_ifd;
 549 };
 550
 551
 552 // ============================================================================
 553 // wxFSWSourceHandler implementation
 554 // ============================================================================
 555
 556 // once we get signaled to read, actuall event reading occurs
 557 void wxFSWSourceHandler::OnReadWaiting()
 558 {
 559     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 560     m_service->ReadEvents();
 561 }
 562
 563 void wxFSWSourceHandler::OnWriteWaiting()
 564 {
 565     wxFAIL_MSG("We never write to inotify descriptor.");
 566 }
 567
 568 void wxFSWSourceHandler::OnExceptionWaiting()
 569 {
 570     wxFAIL_MSG("We never receive exceptions on inotify descriptor.");
 571 }
 572
 573
 574 // ============================================================================
 575 // wxInotifyFileSystemWatcher implementation
 576 // ============================================================================
 577
 578 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher()
 579     : wxFileSystemWatcherBase()
 580 {
 581     Init();
 582 }
 583
 584 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher(const wxFileName& path,
 585                                                        int events)
 586     : wxFileSystemWatcherBase()
 587 {
 588     if (!Init())
 589     {
 590         if (m_service)
 591             delete m_service;
 592         return;
 593     }
 594
 595     Add(path, events);
 596 }
 597
 598 wxInotifyFileSystemWatcher::~wxInotifyFileSystemWatcher()
 599 {
 600 }
 601
 602 bool wxInotifyFileSystemWatcher::Init()
 603 {
 604     m_service = new wxFSWatcherImplUnix(this);
 605     return m_service->Init();
 606 }
 607
 608 void wxInotifyFileSystemWatcher::OnDirDeleted(const wxString& path)
 609 {
 610     if (!path.empty())
 611     {
 612         wxFSWatchInfoMap::iterator it = m_watches.find(path);
 613         wxCHECK_RET(it != m_watches.end(),
 614                     wxString::Format("Path '%s' is not watched", path));
 615
 616         // path has been deleted, so we must forget it whatever its refcount
 617         m_watches.erase(it);
 618     }
 619 }
 620
 621 #endif // wxHAS_INOTIFY
 622
 623 #endif // wxUSE_FSWATCHER