src/common/selectdispatcher.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/selectdispatcher.cpp
   3 // Purpose:     implements dispatcher for select() call
   4 // Author:      Lukasz Michalski and Vadim Zeitlin
   5 // Created:     December 2006
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2006 Lukasz Michalski
   8 // License:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // for compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 #if wxUSE_SELECT_DISPATCHER
  27
  28 #include "wx/private/selectdispatcher.h"
  29 #include "wx/unix/private.h"
  30
  31 #ifndef WX_PRECOMP
  32     #include "wx/hash.h"
  33     #include "wx/log.h"
  34     #include "wx/intl.h"
  35 #endif
  36
  37 #if defined(HAVE_SYS_SELECT_H) || defined(__WATCOMC__)
  38     #include <sys/time.h>
  39     #include <sys/select.h>
  40 #endif
  41
  42 #include <errno.h>
  43
  44 #define wxSelectDispatcher_Trace wxT("selectdispatcher")
  45
  46 // ============================================================================
  47 // implementation
  48 // ============================================================================
  49
  50 // ----------------------------------------------------------------------------
  51 // wxSelectSets
  52 // ----------------------------------------------------------------------------
  53
  54 int wxSelectSets::ms_flags[wxSelectSets::Max] =
  55 {
  56     wxFDIO_INPUT,
  57     wxFDIO_OUTPUT,
  58     wxFDIO_EXCEPTION,
  59 };
  60
  61 const char *wxSelectSets::ms_names[wxSelectSets::Max] =
  62 {
  63     "input",
  64     "output",
  65     "exceptional",
  66 };
  67
  68 wxSelectSets::Callback wxSelectSets::ms_handlers[wxSelectSets::Max] =
  69 {
  70     &wxFDIOHandler::OnReadWaiting,
  71     &wxFDIOHandler::OnWriteWaiting,
  72     &wxFDIOHandler::OnExceptionWaiting,
  73 };
  74
  75 wxSelectSets::wxSelectSets()
  76 {
  77     for ( int n = 0; n < Max; n++ )
  78     {
  79         wxFD_ZERO(&m_fds[n]);
  80     }
  81 }
  82
  83 bool wxSelectSets::HasFD(int fd) const
  84 {
  85     for ( int n = 0; n < Max; n++ )
  86     {
  87         if ( wxFD_ISSET(fd, (fd_set*) &m_fds[n]) )
  88             return true;
  89     }
  90
  91     return false;
  92 }
  93
  94 bool wxSelectSets::SetFD(int fd, int flags)
  95 {
  96     wxCHECK_MSG( fd >= 0, false, wxT("invalid descriptor") );
  97
  98     for ( int n = 0; n < Max; n++ )
  99     {
 100         if ( flags & ms_flags[n] )
 101         {
 102             wxFD_SET(fd, &m_fds[n]);
 103         }
 104         else if ( wxFD_ISSET(fd,  (fd_set*) &m_fds[n]) )
 105         {
 106             wxFD_CLR(fd, &m_fds[n]);
 107         }
 108     }
 109
 110     return true;
 111 }
 112
 113 int wxSelectSets::Select(int nfds, struct timeval *tv)
 114 {
 115     return select(nfds, &m_fds[Read], &m_fds[Write], &m_fds[Except], tv);
 116 }
 117
 118 bool wxSelectSets::Handle(int fd, wxFDIOHandler& handler) const
 119 {
 120     for ( int n = 0; n < Max; n++ )
 121     {
 122         if ( wxFD_ISSET(fd, (fd_set*) &m_fds[n]) )
 123         {
 124             wxLogTrace(wxSelectDispatcher_Trace,
 125                        wxT("Got %s event on fd %d"), ms_names[n], fd);
 126             (handler.*ms_handlers[n])();
 127             // callback can modify sets and destroy handler
 128             // this forces that one event can be processed at one time
 129             return true;
 130         }
 131     }
 132
 133     return false;
 134 }
 135
 136 // ----------------------------------------------------------------------------
 137 // wxSelectDispatcher
 138 // ----------------------------------------------------------------------------
 139
 140 bool wxSelectDispatcher::RegisterFD(int fd, wxFDIOHandler *handler, int flags)
 141 {
 142     if ( !wxMappedFDIODispatcher::RegisterFD(fd, handler, flags) )
 143         return false;
 144
 145     if ( !m_sets.SetFD(fd, flags) )
 146        return false;
 147
 148     if ( fd > m_maxFD )
 149       m_maxFD = fd;
 150
 151     wxLogTrace(wxSelectDispatcher_Trace,
 152                 wxT("Registered fd %d: input:%d, output:%d, exceptional:%d"), fd, (flags & wxFDIO_INPUT) == wxFDIO_INPUT, (flags & wxFDIO_OUTPUT), (flags & wxFDIO_EXCEPTION) == wxFDIO_EXCEPTION);
 153     return true;
 154 }
 155
 156 bool wxSelectDispatcher::ModifyFD(int fd, wxFDIOHandler *handler, int flags)
 157 {
 158     if ( !wxMappedFDIODispatcher::ModifyFD(fd, handler, flags) )
 159         return false;
 160
 161     wxASSERT_MSG( fd <= m_maxFD, wxT("logic error: registered fd > m_maxFD?") );
 162
 163     wxLogTrace(wxSelectDispatcher_Trace,
 164                 wxT("Modified fd %d: input:%d, output:%d, exceptional:%d"), fd, (flags & wxFDIO_INPUT) == wxFDIO_INPUT, (flags & wxFDIO_OUTPUT) == wxFDIO_OUTPUT, (flags & wxFDIO_EXCEPTION) == wxFDIO_EXCEPTION);
 165     return m_sets.SetFD(fd, flags);
 166 }
 167
 168 bool wxSelectDispatcher::UnregisterFD(int fd)
 169 {
 170     m_sets.ClearFD(fd);
 171
 172     if ( !wxMappedFDIODispatcher::UnregisterFD(fd) )
 173         return false;
 174
 175     // remove the handler if we don't need it any more
 176     if ( !m_sets.HasFD(fd) )
 177     {
 178         if ( fd == m_maxFD )
 179         {
 180             // need to find new max fd
 181             m_maxFD = -1;
 182             for ( wxFDIOHandlerMap::const_iterator it = m_handlers.begin();
 183                   it != m_handlers.end();
 184                   ++it )
 185             {
 186                 if ( it->first > m_maxFD )
 187                 {
 188                     m_maxFD = it->first;
 189                 }
 190             }
 191         }
 192     }
 193
 194     wxLogTrace(wxSelectDispatcher_Trace,
 195                 wxT("Removed fd %d, current max: %d"), fd, m_maxFD);
 196     return true;
 197 }
 198
 199 int wxSelectDispatcher::ProcessSets(const wxSelectSets& sets)
 200 {
 201     int numEvents = 0;
 202     for ( int fd = 0; fd <= m_maxFD; fd++ )
 203     {
 204         if ( !sets.HasFD(fd) )
 205             continue;
 206
 207         wxFDIOHandler * const handler = FindHandler(fd);
 208         if ( !handler )
 209         {
 210             wxFAIL_MSG( wxT("NULL handler in wxSelectDispatcher?") );
 211             continue;
 212         }
 213
 214         if ( sets.Handle(fd, *handler) )
 215             numEvents++;
 216     }
 217
 218     return numEvents;
 219 }
 220
 221 int wxSelectDispatcher::DoSelect(wxSelectSets& sets, int timeout) const
 222 {
 223     struct timeval tv,
 224                   *ptv;
 225     if ( timeout != TIMEOUT_INFINITE )
 226     {
 227         ptv = &tv;
 228         tv.tv_sec = 0;
 229         tv.tv_usec = timeout*1000;
 230     }
 231     else // no timeout
 232     {
 233         ptv = NULL;
 234     }
 235
 236     int ret = sets.Select(m_maxFD + 1, ptv);
 237
 238     // TODO: we need to restart select() in this case but for now just return
 239     //       as if timeout expired
 240     if ( ret == -1 && errno == EINTR )
 241         ret = 0;
 242
 243     return ret;
 244 }
 245
 246 bool wxSelectDispatcher::HasPending() const
 247 {
 248     wxSelectSets sets(m_sets);
 249     return DoSelect(sets, 0) > 0;
 250 }
 251
 252 int wxSelectDispatcher::Dispatch(int timeout)
 253 {
 254     wxSelectSets sets(m_sets);
 255     switch ( DoSelect(sets, timeout) )
 256     {
 257         case -1:
 258             wxLogSysError(_("Failed to monitor I/O channels"));
 259             return -1;
 260
 261         case 0:
 262             // timeout expired without anything happening
 263             return 0;
 264
 265         default:
 266             return ProcessSets(sets);
 267     }
 268 }
 269
 270 #endif // wxUSE_SELECT_DISPATCHER