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
 240         // wd will be -1 for IN_Q_OVERFLOW, which would trigger the wxFAIL_MSG
 241         if (inevt.wd != -1)
 242         {
 243             if (it == m_watchMap.end())
 244             {
 245                 // It's not in the map; check if was recently removed from it.
 246                 if (m_staleDescriptors.Index(inevt.wd) != wxNOT_FOUND)
 247                 {
 248                     wxLogTrace(wxTRACE_FSWATCHER,
 249                                "Got an event for stale wd %i", inevt.wd);
 250                 }
 251                 else
 252                 {
 253                     wxFAIL_MSG("Event for unknown watch descriptor.");
 254                 }
 255
 256                 // In any case, don't process this event: it's either for an
 257                 // already removed entry, or for a completely unknown one.
 258                 return;
 259             }
 260         }
 261
 262         int nativeFlags = inevt.mask;
 263         int flags = Native2WatcherFlags(nativeFlags);
 264
 265         // check out for error/warning condition
 266         if (flags & wxFSW_EVENT_WARNING || flags & wxFSW_EVENT_ERROR)
 267         {
 268             wxString errMsg = GetErrorDescription(nativeFlags);
 269             wxFileSystemWatcherEvent event(flags, errMsg);
 270             SendEvent(event);
 271             return;
 272         }
 273
 274         wxFSWatchEntry& watch = *(it->second);
 275
 276         // Now IN_UNMOUNT. We must do so here, as it's not in the watch flags
 277         if (nativeFlags & IN_UNMOUNT)
 278         {
 279             wxFileName path = GetEventPath(watch, inevt);
 280             wxFileSystemWatcherEvent event(wxFSW_EVENT_UNMOUNT, path, path);
 281             SendEvent(event);
 282         }
 283         // filter out ignored events and those not asked for.
 284         // we never filter out warnings or exceptions
 285         else if ((flags == 0) || !(flags & watch.GetFlags()))
 286         {
 287             return;
 288         }
 289
 290         // Creation
 291         // We need do something here only if the original watch was recursive;
 292         // we don't watch a child dir itself inside a non-tree watch.
 293         // We watch only dirs explicitly, so we don't want file IN_CREATEs.
 294         // Distinguish by whether nativeFlags contain IN_ISDIR
 295         else if ((nativeFlags & IN_CREATE) &&
 296                  (watch.GetType() == wxFSWPath_Tree) && (inevt.mask & IN_ISDIR))
 297         {
 298             wxFileName fn = GetEventPath(watch, inevt);
 299             // Though it's a dir, fn treats it as a file. So:
 300             fn.AssignDir(fn.GetFullPath());
 301
 302             if (m_watcher->AddAny(fn, wxFSW_EVENT_ALL,
 303                                    wxFSWPath_Tree, watch.GetFilespec()))
 304             {
 305                 // Tell the owner, in case it's interested
 306                 // If there's a filespec, assume he's not
 307                 if (watch.GetFilespec().empty())
 308                 {
 309                     wxFileSystemWatcherEvent event(flags, fn, fn);
 310                     SendEvent(event);
 311                 }
 312             }
 313         }
 314
 315         // Deletion
 316         // We watch only dirs explicitly, so we don't want file IN_DELETEs.
 317         // We obviously can't check using DirExists() as the object has been
 318         // deleted; and nativeFlags here doesn't contain IN_ISDIR, even for
 319         // a dir. Fortunately IN_DELETE_SELF doesn't happen for files. We need
 320         // to do something here only inside a tree watch, or if it's the parent
 321         // dir that's deleted. Otherwise let the parent dir cope
 322         else if ((nativeFlags & IN_DELETE_SELF) &&
 323                     ((watch.GetType() == wxFSWPath_Dir) ||
 324                      (watch.GetType() == wxFSWPath_Tree)))
 325         {
 326             // We must remove the deleted directory from the map, so that
 327             // DoRemoveInotify() isn't called on it in the future. Don't assert
 328             // if the wd isn't found: repeated IN_DELETE_SELFs can occur
 329             wxFileName fn = GetEventPath(watch, inevt);
 330             wxString path(fn.GetPathWithSep());
 331
 332             if (m_watchMap.erase(inevt.wd) == 1)
 333             {
 334                 // Delete from wxFileSystemWatcher
 335                 wxDynamicCast(m_watcher, wxInotifyFileSystemWatcher)->
 336                                             OnDirDeleted(path);
 337
 338                 // Now remove from our local list of watched items
 339                 wxFSWatchEntries::iterator wit =
 340                                         m_watches.find(path);
 341                 if (wit != m_watches.end())
 342                 {
 343                     m_watches.erase(wit);
 344                 }
 345
 346                 // Cache the wd in case any events arrive late
 347                 m_staleDescriptors.Add(inevt.wd);
 348             }
 349
 350             // Tell the owner, in case it's interested
 351             // If there's a filespec, assume he's not
 352             if (watch.GetFilespec().empty())
 353             {
 354                 wxFileSystemWatcherEvent event(flags, fn, fn);
 355                 SendEvent(event);
 356             }
 357         }
 358
 359         // renames
 360         else if (nativeFlags & IN_MOVE)
 361         {
 362             wxInotifyCookies::iterator it2 = m_cookies.find(inevt.cookie);
 363             if ( it2 == m_cookies.end() )
 364             {
 365                 int size = sizeof(inevt) + inevt.len;
 366                 inotify_event* e = (inotify_event*) operator new (size);
 367                 memcpy(e, &inevt, size);
 368
 369                 wxInotifyCookies::value_type val(e->cookie, e);
 370                 m_cookies.insert(val);
 371             }
 372             else
 373             {
 374                 inotify_event& oldinevt = *(it2->second);
 375
 376                 // Tell the owner, in case it's interested
 377                 // If there's a filespec, assume he's not
 378                 if ( watch.GetFilespec().empty() )
 379                 {
 380                     wxFileSystemWatcherEvent event(flags);
 381                     if ( inevt.mask & IN_MOVED_FROM )
 382                     {
 383                         event.SetPath(GetEventPath(watch, inevt));
 384                         event.SetNewPath(GetEventPath(watch, oldinevt));
 385                     }
 386                     else
 387                     {
 388                         event.SetPath(GetEventPath(watch, oldinevt));
 389                         event.SetNewPath(GetEventPath(watch, inevt));
 390                     }
 391                     SendEvent(event);
 392                 }
 393
 394                 m_cookies.erase(it2);
 395                 delete &oldinevt;
 396             }
 397         }
 398         // every other kind of event
 399         else
 400         {
 401             wxFileName path = GetEventPath(watch, inevt);
 402             // For files, check that it matches any filespec
 403             if ( MatchesFilespec(path, watch.GetFilespec()) )
 404             {
 405                 wxFileSystemWatcherEvent event(flags, path, path);
 406                 SendEvent(event);
 407             }
 408         }
 409     }
 410
 411     void ProcessRenames()
 412     {
 413         wxInotifyCookies::iterator it = m_cookies.begin();
 414         while ( it != m_cookies.end() )
 415         {
 416             inotify_event& inevt = *(it->second);
 417
 418             wxLogTrace(wxTRACE_FSWATCHER, "Processing pending rename events");
 419             wxLogTrace(wxTRACE_FSWATCHER, InotifyEventToString(inevt));
 420
 421             // get watch entry for this event
 422             wxFSWatchEntryDescriptors::iterator wit = m_watchMap.find(inevt.wd);
 423             wxCHECK_RET(wit != m_watchMap.end(),
 424                              "Watch descriptor not present in the watch map!");
 425
 426             // Tell the owner, in case it's interested
 427             // If there's a filespec, assume he's not
 428             wxFSWatchEntry& watch = *(wit->second);
 429             if ( watch.GetFilespec().empty() )
 430             {
 431                 int flags = Native2WatcherFlags(inevt.mask);
 432                 wxFileName path = GetEventPath(watch, inevt);
 433                 {
 434                     wxFileSystemWatcherEvent event(flags, path, path);
 435                     SendEvent(event);
 436                 }
 437             }
 438
 439             m_cookies.erase(it);
 440             delete &inevt;
 441             it = m_cookies.begin();
 442         }
 443     }
 444
 445     void SendEvent(wxFileSystemWatcherEvent& evt)
 446     {
 447         wxLogTrace(wxTRACE_FSWATCHER, evt.ToString());
 448         m_watcher->GetOwner()->ProcessEvent(evt);
 449     }
 450
 451     int ReadEventsToBuf(char* buf, int size)
 452     {
 453         wxCHECK_MSG( IsOk(), false,
 454                     "Inotify not initialized or invalid inotify descriptor" );
 455
 456         memset(buf, 0, size);
 457         ssize_t left = read(m_ifd, buf, size);
 458         if (left == -1)
 459         {
 460             wxLogSysError(_("Unable to read from inotify descriptor"));
 461             return -1;
 462         }
 463         else if (left == 0)
 464         {
 465             wxLogWarning(_("EOF while reading from inotify descriptor"));
 466             return -1;
 467         }
 468
 469         return left;
 470     }
 471
 472     static wxString InotifyEventToString(const inotify_event& inevt)
 473     {
 474         wxString mask = (inevt.mask & IN_ISDIR) ?
 475                         wxString::Format("IS_DIR | %u", inevt.mask & ~IN_ISDIR) :
 476                         wxString::Format("%u", inevt.mask);
 477         const char* name = "";
 478         if (inevt.len)
 479             name = inevt.name;
 480         return wxString::Format("Event: wd=%d, mask=%s, cookie=%u, len=%u, "
 481                                 "name=%s", inevt.wd, mask, inevt.cookie,
 482                                 inevt.len, name);
 483     }
 484
 485     static wxFileName GetEventPath(const wxFSWatchEntry& watch,
 486                                    const inotify_event& inevt)
 487     {
 488         // only when dir is watched, we have non-empty e.name
 489         wxFileName path = watch.GetPath();
 490         if (path.IsDir() && inevt.len)
 491         {
 492             path = wxFileName(path.GetPath(), inevt.name);
 493         }
 494         return path;
 495     }
 496
 497     static int Watcher2NativeFlags(int flags)
 498     {
 499         // Start with the standard case of wanting all events
 500         if (flags == wxFSW_EVENT_ALL)
 501         {
 502             return IN_ALL_EVENTS;
 503         }
 504
 505         static const int flag_mapping[][2] = {
 506             { wxFSW_EVENT_ACCESS, IN_ACCESS   },
 507             { wxFSW_EVENT_MODIFY, IN_MODIFY   },
 508             { wxFSW_EVENT_ATTRIB, IN_ATTRIB   },
 509             { wxFSW_EVENT_RENAME, IN_MOVE     },
 510             { wxFSW_EVENT_CREATE, IN_CREATE   },
 511             { wxFSW_EVENT_DELETE, IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF },
 512             { wxFSW_EVENT_UNMOUNT, IN_UNMOUNT }
 513             // wxFSW_EVENT_ERROR/WARNING make no sense here
 514         };
 515
 516         int native_flags = 0;
 517         for ( unsigned int i=0; i < WXSIZEOF(flag_mapping); ++i)
 518         {
 519             if (flags & flag_mapping[i][0])
 520                 native_flags |= flag_mapping[i][1];
 521         }
 522
 523         return native_flags;
 524     }
 525
 526     static int Native2WatcherFlags(int flags)
 527     {
 528         static const int flag_mapping[][2] = {
 529             { IN_ACCESS,        wxFSW_EVENT_ACCESS }, // generated during read!
 530             { IN_MODIFY,        wxFSW_EVENT_MODIFY },
 531             { IN_ATTRIB,        wxFSW_EVENT_ATTRIB },
 532             { IN_CLOSE_WRITE,   0 },
 533             { IN_CLOSE_NOWRITE, 0 },
 534             { IN_OPEN,          0 },
 535             { IN_MOVED_FROM,    wxFSW_EVENT_RENAME },
 536             { IN_MOVED_TO,      wxFSW_EVENT_RENAME },
 537             { IN_CREATE,        wxFSW_EVENT_CREATE },
 538             { IN_DELETE,        wxFSW_EVENT_DELETE },
 539             { IN_DELETE_SELF,   wxFSW_EVENT_DELETE },
 540             { IN_MOVE_SELF,     wxFSW_EVENT_DELETE },
 541
 542             { IN_UNMOUNT,       wxFSW_EVENT_UNMOUNT},
 543             { IN_Q_OVERFLOW,    wxFSW_EVENT_WARNING},
 544
 545             // ignored, because this is generated mainly by watcher::Remove()
 546             { IN_IGNORED,        0 }
 547         };
 548
 549         unsigned int i=0;
 550         for ( ; i < WXSIZEOF(flag_mapping); ++i) {
 551             // in this mapping multiple flags at once don't happen
 552             if (flags & flag_mapping[i][0])
 553                 return flag_mapping[i][1];
 554         }
 555
 556         // never reached
 557         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flags));
 558         return -1;
 559     }
 560
 561     /**
 562      * Returns error description for specified inotify mask
 563      */
 564     static const wxString GetErrorDescription(int flag)
 565     {
 566         switch ( flag )
 567         {
 568         case IN_Q_OVERFLOW:
 569             return _("Event queue overflowed");
 570         }
 571
 572         // never reached
 573         wxFAIL_MSG(wxString::Format("Unknown inotify event mask %u", flag));
 574         return wxEmptyString;
 575     }
 576
 577     wxFSWSourceHandler* m_handler;        // handler for inotify event source
 578     wxFSWatchEntryDescriptors m_watchMap; // inotify wd=>wxFSWatchEntry* map
 579     wxArrayInt m_staleDescriptors;        // stores recently-removed watches
 580     wxInotifyCookies m_cookies;           // map to track renames
 581     wxEventLoopSource* m_source;          // our event loop source
 582
 583     // file descriptor created by inotify_init()
 584     int m_ifd;
 585 };
 586
 587
 588 // ============================================================================
 589 // wxFSWSourceHandler implementation
 590 // ============================================================================
 591
 592 // once we get signaled to read, actuall event reading occurs
 593 void wxFSWSourceHandler::OnReadWaiting()
 594 {
 595     wxLogTrace(wxTRACE_FSWATCHER, "--- OnReadWaiting ---");
 596     m_service->ReadEvents();
 597 }
 598
 599 void wxFSWSourceHandler::OnWriteWaiting()
 600 {
 601     wxFAIL_MSG("We never write to inotify descriptor.");
 602 }
 603
 604 void wxFSWSourceHandler::OnExceptionWaiting()
 605 {
 606     wxFAIL_MSG("We never receive exceptions on inotify descriptor.");
 607 }
 608
 609
 610 // ============================================================================
 611 // wxInotifyFileSystemWatcher implementation
 612 // ============================================================================
 613
 614 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher()
 615     : wxFileSystemWatcherBase()
 616 {
 617     Init();
 618 }
 619
 620 wxInotifyFileSystemWatcher::wxInotifyFileSystemWatcher(const wxFileName& path,
 621                                                        int events)
 622     : wxFileSystemWatcherBase()
 623 {
 624     if (!Init())
 625     {
 626         if (m_service)
 627             delete m_service;
 628         return;
 629     }
 630
 631     Add(path, events);
 632 }
 633
 634 wxInotifyFileSystemWatcher::~wxInotifyFileSystemWatcher()
 635 {
 636 }
 637
 638 bool wxInotifyFileSystemWatcher::Init()
 639 {
 640     m_service = new wxFSWatcherImplUnix(this);
 641     return m_service->Init();
 642 }
 643
 644 void wxInotifyFileSystemWatcher::OnDirDeleted(const wxString& path)
 645 {
 646     if (!path.empty())
 647     {
 648         wxFSWatchInfoMap::iterator it = m_watches.find(path);
 649         wxCHECK_RET(it != m_watches.end(),
 650                     wxString::Format("Path '%s' is not watched", path));
 651
 652         // path has been deleted, so we must forget it whatever its refcount
 653         m_watches.erase(it);
 654     }
 655 }
 656
 657 #endif // wxHAS_INOTIFY
 658
 659 #endif // wxUSE_FSWATCHER