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