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(nativeFlags);
 265             wxFileSystemWatcherEvent event(flags, errMsg);
 266             SendEvent(event);
 267         }
 268         // Now IN_UNMOUNT. We must do so here, as it's not in the watch flags
 269         if (nativeFlags & IN_UNMOUNT)
 270         {
 271             wxFileName path = GetEventPath(watch, inevt);
 272             wxFileSystemWatcherEvent event(wxFSW_EVENT_UNMOUNT, path, path);
 273             SendEvent(event);
 274         }
 275         // filter out ignored events and those not asked for.
 276         // we never filter out warnings or exceptions
 277         else if ((flags == 0) || !(flags & watch.GetFlags()))
 278         {
 279             return;
 280         }
 281
 282         // Creation
 283         // We need do something here only if the original watch was recursive;
 284         // we don't watch a child dir itself inside a non-tree watch.
 285         // We watch only dirs explicitly, so we don't want file IN_CREATEs.
 286         // Distinguish by whether nativeFlags contain IN_ISDIR
 287         else if ((nativeFlags & IN_CREATE) &&
 288                  (watch.GetType() == wxFSWPath_Tree) && (inevt.mask & IN_ISDIR))
 289         {
 290             wxFileName fn = GetEventPath(watch, inevt);
 291             // Though it's a dir, fn treats it as a file. So:
 292             fn.AssignDir(fn.GetFullPath());
 293
 294             if (m_watcher->AddAny(fn, wxFSW_EVENT_ALL,
 295                                    wxFSWPath_Tree, watch.GetFilespec()))
 296             {
 297                 // Tell the owner, in case it's interested
 298                 // If there's a filespec, assume he's not
 299                 if (watch.GetFilespec().empty())
 300                 {
 301                     wxFileSystemWatcherEvent event(flags, fn, fn);
 302                     SendEvent(event);
 303                 }
 304             }
 305         }
 306
 307         // Deletion
 308         // We watch only dirs explicitly, so we don't want file IN_DELETEs.
 309         // We obviously can't check using DirExists() as the object has been
 310         // deleted; and nativeFlags here doesn't contain IN_ISDIR, even for
 311         // a dir. Fortunately IN_DELETE_SELF doesn't happen for files. We need
 312         // to do something here only inside a tree watch, or if it's the parent
 313         // dir that's deleted. Otherwise let the parent dir cope
 314         else if ((nativeFlags & IN_DELETE_SELF) &&
 315                     ((watch.GetType() == wxFSWPath_Dir) ||
 316                      (watch.GetType() == wxFSWPath_Tree)))
 317         {
 318             // We must remove the deleted directory from the map, so that
 319             // DoRemoveInotify() isn't called on it in the future. Don't assert
 320             // if the wd isn't found: repeated IN_DELETE_SELFs can occur
 321             wxFileName fn = GetEventPath(watch, inevt);
 322             wxString path(fn.GetPathWithSep());
 323
 324             if (m_watchMap.erase(inevt.wd) == 1)
 325             {
 326                 // Delete from wxFileSystemWatcher
 327                 wxDynamicCast(m_watcher, wxInotifyFileSystemWatcher)->
 328                                             OnDirDeleted(path);
 329
 330                 // Now remove from our local list of watched items
 331                 wxFSWatchEntries::iterator wit =
 332                                         m_watches.find(path);
 333                 if (wit != m_watches.end())
 334                 {
 335                     m_watches.erase(wit);
 336                 }
 337
 338                 // Cache the wd in case any events arrive late
 339                 m_staleDescriptors.Add(inevt.wd);
 340             }
 341
 342             // Tell the owner, in case it's interested
 343             // If there's a filespec, assume he's not
 344             if (watch.GetFilespec().empty())
 345             {
 346                 wxFileSystemWatcherEvent event(flags, fn, fn);
 347                 SendEvent(event);
 348             }
 349         }
 350
 351         // renames
 352         else if (nativeFlags & IN_MOVE)
 353         {
 354             wxInotifyCookies::iterator it2 = m_cookies.find(inevt.cookie);
 355             if ( it2 == m_cookies.end() )
 356             {
 357                 int size = sizeof(inevt) + inevt.len;
 358                 inotify_event* e = (inotify_event*) operator new (size);
 359                 memcpy(e, &inevt, size);
 360
 361                 wxInotifyCookies::value_type val(e->cookie, e);
 362                 m_cookies.insert(val);
 363             }
 364             else
 365             {
 366                 inotify_event& oldinevt = *(it2->second);
 367
 368                 // Tell the owner, in case it's interested
 369                 // If there's a filespec, assume he's not
 370                 if ( watch.GetFilespec().empty() )
 371                 {
 372                     wxFileSystemWatcherEvent event(flags);
 373                     if ( inevt.mask & IN_MOVED_FROM )
 374                     {
 375                         event.SetPath(GetEventPath(watch, inevt));
 376                         event.SetNewPath(GetEventPath(watch, oldinevt));
 377                     }
 378                     else
 379                     {
 380                         event.SetPath(GetEventPath(watch, oldinevt));
 381                         event.SetNewPath(GetEventPath(watch, inevt));
 382                     }
 383                     SendEvent(event);
 384                 }
 385
 386                 m_cookies.erase(it2);
 387                 delete &oldinevt;
 388             }
 389         }
 390         // every other kind of event
 391         else
 392         {
 393             wxFileName path = GetEventPath(watch, inevt);
 394             // For files, check that it matches any filespec
 395             if ( MatchesFilespec(path, watch.GetFilespec()) )
 396             {
 397                 wxFileSystemWatcherEvent event(flags, path, path);
 398                 SendEvent(event);
 399             }
 400         }
 401     }
 402
 403     void ProcessRenames()
 404     {
 405         wxInotifyCookies::iterator it = m_cookies.begin();
 406         while ( it != m_cookies.end() )
 407         {
 408             inotify_event& inevt = *(it->second);
 409
 410             wxLogTrace(wxTRACE_FSWATCHER, "Processing pending rename events");
 411             wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 412
 413             // get watch entry for this event
 414             wxFSWatchEntryDescriptors::iterator wit = m_watchMap.find(inevt.wd);
 415             wxCHECK_RET(wit != m_watchMap.end(),
 416                              "Watch descriptor not present in the watch map!");
 417
 418             // Tell the owner, in case it's interested
 419             // If there's a filespec, assume he's not
 420             wxFSWatchEntry& watch = *(wit->second);
 421             if ( watch.GetFilespec().empty() )
 422             {
 423                 int flags = Native2WatcherFlags(inevt.mask);
 424                 wxFileName path = GetEventPath(watch, inevt);
 425                 {
 426                     wxFileSystemWatcherEvent event(flags, path, path);
 427                     SendEvent(event);
 428                 }
 429             }
 430
 431             m_cookies.erase(it);
 432             delete &inevt;
 433             it = m_cookies.begin();
 434         }
 435     }
 436
 437     void SendEvent(wxFileSystemWatcherEvent& evt)
 438     {
 439         wxLogTrace(wxTRACE_FSWATCHER, evt.ToString());
 440         m_watcher->GetOwner()->ProcessEvent(evt);
 441     }
 442
 443     int ReadEventsToBuf(char* buf, int size)
 444     {
 445         wxCHECK_MSG( IsOk(), false,
 446                     "Inotify not initialized or invalid inotify descriptor" );
 447
 448         memset(buf, 0, size);
 449         ssize_t left = read(m_ifd, buf, size);
 450         if (left == -1)
 451         {
 452             wxLogSysError(_("Unable to read from inotify descriptor"));
 453             return -1;
 454         }
 455         else if (left == 0)
 456         {
 457             wxLogWarning(_("EOF while reading from inotify descriptor"));
 458             return -1;
 459         }
 460
 461         return left;
 462     }
 463
 464     static wxString InotifyEventToString(const inotify_event& inevt)
 465     {
 466         wxString mask = (inevt.mask & IN_ISDIR) ?
 467                         wxString::Format("IS_DIR | %u", inevt.mask & ~IN_ISDIR) :
 468                         wxString::Format("%u", inevt.mask);
 469         const char* name = "";
 470         if (inevt.len)
 471             name = inevt.name;
 472         return wxString::Format("Event: wd=%d, mask=%s, cookie=%u, len=%u, "
 473                                 "name=%s", inevt.wd, mask, inevt.cookie,
 474                                 inevt.len, name);
 475     }
 476
 477     static wxFileName GetEventPath(const wxFSWatchEntry& watch,
 478                                    const inotify_event& inevt)
 479     {
 480         // only when dir is watched, we have non-empty e.name
 481         wxFileName path = watch.GetPath();
 482         if (path.IsDir() && inevt.len)
 483         {
 484             path = wxFileName(path.GetPath(), inevt.name);
 485         }
 486         return path;
 487     }
 488
 489     static int Watcher2NativeFlags(int flags)
 490     {
 491         // Start with the standard case of wanting all events
 492         if (flags == wxFSW_EVENT_ALL)
 493         {
 494             return IN_ALL_EVENTS;
 495         }
 496
 497         static const int flag_mapping[][2] = {
 498             { wxFSW_EVENT_ACCESS, IN_ACCESS   },
 499             { wxFSW_EVENT_MODIFY, IN_MODIFY   },
 500             { wxFSW_EVENT_ATTRIB, IN_ATTRIB   },
 501             { wxFSW_EVENT_RENAME, IN_MOVE     },
 502             { wxFSW_EVENT_CREATE, IN_CREATE   },
 503             { wxFSW_EVENT_DELETE, IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF },
 504             { wxFSW_EVENT_UNMOUNT, IN_UNMOUNT }
 505             // wxFSW_EVENT_ERROR/WARNING make no sense here
 506         };
 507
 508         int native_flags = 0;
 509         for ( unsigned int i=0; i < WXSIZEOF(flag_mapping); ++i)
 510         {
 511             if (flags & flag_mapping[i][0])
 512                 native_flags |= flag_mapping[i][1];
 513         }
 514
 515         return native_flags;
 516     }
 517
 518     static int Native2WatcherFlags(int flags)
 519     {
 520         static const int flag_mapping[][2] = {
 521             { IN_ACCESS,        wxFSW_EVENT_ACCESS }, // generated during read!
 522             { IN_MODIFY,        wxFSW_EVENT_MODIFY },
 523             { IN_ATTRIB,        wxFSW_EVENT_ATTRIB },
 524             { IN_CLOSE_WRITE,   0 },
 525             { IN_CLOSE_NOWRITE, 0 },
 526             { IN_OPEN,          0 },
 527             { IN_MOVED_FROM,    wxFSW_EVENT_RENAME },
 528             { IN_MOVED_TO,      wxFSW_EVENT_RENAME },
 529             { IN_CREATE,        wxFSW_EVENT_CREATE },
 530             { IN_DELETE,        wxFSW_EVENT_DELETE },
 531             { IN_DELETE_SELF,   wxFSW_EVENT_DELETE },
 532             { IN_MOVE_SELF,     wxFSW_EVENT_DELETE },
 533
 534             { IN_UNMOUNT,       wxFSW_EVENT_UNMOUNT},
 535             { IN_Q_OVERFLOW,    wxFSW_EVENT_WARNING},
 536
 537             // ignored, because this is generated mainly by watcher::Remove()
 538             { IN_IGNORED,        0 }
 539         };
 540
 541         unsigned int i=0;
 542         for ( ; i < WXSIZEOF(flag_mapping); ++i) {
 543             // in this mapping multiple flags at once don't happen
 544             if (flags & flag_mapping[i][0])
 545                 return flag_mapping[i][1];
 546         }
 547
 548         // never reached
 549         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flags));
 550         return -1;
 551     }
 552
 553     /**
 554      * Returns error description for specified inotify mask
 555      */
 556     static const wxString GetErrorDescription(int flag)
 557     {
 558         switch ( flag )
 559         {
 560         case IN_Q_OVERFLOW:
 561             return _("Event queue overflowed");
 562         }
 563
 564         // never reached
 565         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flag));
 566         return wxEmptyString;
 567     }
 568
 569     wxFSWSourceHandler* m_handler;        // handler for inotify event source
 570     wxFSWatchEntryDescriptors m_watchMap; // inotify wd=>wxFSWatchEntry* map
 571     wxArrayInt m_staleDescriptors;        // stores recently-removed watches
 572     wxInotifyCookies m_cookies;           // map to track renames
 573     wxEventLoopSource* m_source;          // our event loop source
 574
 575     // file descriptor created by inotify_init()
 576     int m_ifd;
 577 };
 578
 579
 580 // ============================================================================
 581 // wxFSWSourceHandler implementation
 582 // ============================================================================
 583
 584 // once we get signaled to read, actuall event reading occurs
 585 void wxFSWSourceHandler::OnReadWaiting()
 586 {
 587     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 588     m_service->ReadEvents();
 589 }
 590
 591 void wxFSWSourceHandler::OnWriteWaiting()
 592 {
 593     wxFAIL_MSG("We never write to inotify descriptor.");
 594 }
 595
 596 void wxFSWSourceHandler::OnExceptionWaiting()
 597 {
 598     wxFAIL_MSG("We never receive exceptions on inotify descriptor.");
 599 }
 600
 601
 602 // ============================================================================
 603 // wxInotifyFileSystemWatcher implementation
 604 // ============================================================================
 605
 606 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher()
 607     : wxFileSystemWatcherBase()
 608 {
 609     Init();
 610 }
 611
 612 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher(const wxFileName& path,
 613                                                        int events)
 614     : wxFileSystemWatcherBase()
 615 {
 616     if (!Init())
 617     {
 618         if (m_service)
 619             delete m_service;
 620         return;
 621     }
 622
 623     Add(path, events);
 624 }
 625
 626 wxInotifyFileSystemWatcher::~wxInotifyFileSystemWatcher()
 627 {
 628 }
 629
 630 bool wxInotifyFileSystemWatcher::Init()
 631 {
 632     m_service = new wxFSWatcherImplUnix(this);
 633     return m_service->Init();
 634 }
 635
 636 void wxInotifyFileSystemWatcher::OnDirDeleted(const wxString& path)
 637 {
 638     if (!path.empty())
 639     {
 640         wxFSWatchInfoMap::iterator it = m_watches.find(path);
 641         wxCHECK_RET(it != m_watches.end(),
 642                     wxString::Format("Path '%s' is not watched", path));
 643
 644         // path has been deleted, so we must forget it whatever its refcount
 645         m_watches.erase(it);
 646     }
 647 }
 648
 649 #endif // wxHAS_INOTIFY
 650
 651 #endif // wxUSE_FSWATCHER