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