--- gvpe/src/iom.C	2003/03/28 05:40:54	1.7
+++ gvpe/src/iom.C	2005/04/26 00:55:56	1.32
@@ -1,7 +1,10 @@
 /*
-    iom.C -- I/O multiplexor
+    iom.C -- generic I/O multiplexer
+    Copyright (C) 2003, 2004 Marc Lehmann <gvpe@schmorp.de>
  
-    This program is free software; you can redistribute it and/or modify
+    This file is part of GVPE.
+
+    GVPE is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.
@@ -12,189 +15,450 @@
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+    along with gvpe; if not, write to the Free Software
+    Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
-#include "config.h"
+#include "iom.h"
+
+#include <cstdio>
+#include <cstdlib>
+#include <cerrno>
 
 #include <sys/time.h>
 
-#include <algorithm>
-#include <functional>
+#include <assert.h>
 
-#include "slog.h"
-#include "iom.h"
+#if 1 // older unices need these includes for select (2)
+# include <unistd.h>
+# include <sys/types.h>
+# include <time.h>
+#endif
+
+// for IOM_SIG
+#if IOM_SIG
+# include <csignal>
+# include <fcntl.h>
+#endif
+
+// if the BSDs would at least be marginally POSIX-compatible.. *sigh*
+// until that happens, sys/select.h must come last
+#include <sys/select.h>
+
+#define TIMEVAL timeval
+#define TV_FRAC tv_usec
+#define TV_MULT 1000000L
+
+#if IOM_IO
+static io_manager_vec<io_watcher>    iow;
+#endif
+#if IOM_CHECK
+static io_manager_vec<check_watcher> cw;
+#endif
+#if IOM_TIME
+static io_manager_vec<time_watcher>  tw;
+#endif
+#if IOM_IDLE
+static io_manager_vec<idle_watcher>  iw;
+#endif
+#if IOM_SIG
+static int sigpipe[2]; // signal signalling pipe
+static sigset_t sigs;
+struct sig_vec : io_manager_vec<sig_watcher> {
+  int pending;
+  sig_vec ()
+    : pending (false)
+    { }
+};
+static vector<sig_vec *> sw;
+#endif
+
+// this is a dummy time watcher to ensure that the first
+// time watcher is _always_ valid, this gets rid of a lot
+// of null-pointer-checks
+// (must come _before_ iom is being defined)
+static struct tw0 : time_watcher
+  {
+    void cb (time_watcher &w)
+    {
+      // should never get called
+      // reached end-of-time, or tstamp has a bogus definition,
+      // or compiler initialisation order broken, or something else :)
+      abort ();
+    }
 
-inline bool lowest_first (const time_watcher *a, const time_watcher *b)
-{
-  return a->at > b->at;
-}
+    tw0 ()
+      : time_watcher (this, &tw0::cb)
+      { }
+  } tw0;
 
 tstamp NOW;
 
-io_manager iom;
-
-void time_watcher::set (tstamp when)
+#if IOM_TIME
+tstamp io_manager::now ()
 {
-  at = when;
+  struct timeval tv;
 
-  if (registered)
-    iom.reschedule_time_watchers ();
-  else
-    iom.reg (this);
+  gettimeofday (&tv, 0);
+  return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.;
 }
 
-void time_watcher::trigger ()
+void io_manager::set_now ()
 {
-  call (at);
-
-  if (registered)
-    iom.reschedule_time_watchers ();
-  else
-    iom.reg (this);
+  NOW = now ();
 }
+#endif
+
+static bool iom_valid;
+
+// used for initialisation only
+static struct init {
+  init ()
+  {
+#if IOM_SIG
+    sigemptyset (&sigs);
+
+    if (pipe (sigpipe))
+      {
+        perror ("io_manager: unable to create signal pipe, aborting.");
+        abort ();
+      }
+
+    fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC);
+    fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC);
+#endif
+
+    iom_valid = true;
+
+#if IOM_TIME
+    io_manager::set_now ();
+
+    tw0.start (TSTAMP_MAX);
+#endif
+  }
 
-void time_watcher::start ()
+  static void required ();
+} init;
+
+void
+init::required ()
 {
-  if (!registered)
-    iom.reg (this);
+  if (!iom_valid)
+    {
+      write (2, "io_manager: early registration attempt, aborting.\n",
+                sizeof ("io_manager: early registration attempt, aborting.\n") - 1);
+      abort ();
+    }
 }
 
-void io_manager::reg (int fd, short events, io_watcher *w)
+template<class watcher>
+void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue)
 {
-  pollfd pfd;
+  init::required ();
 
-  pfd.fd     = fd;
-  pfd.events = events;
-
-  pfs.push_back (pfd);
-  iow.push_back (w);
+  if (!w.active)
+    {
+      queue.push_back (&w);
+      w.active = queue.size ();
+    }
 }
 
-void io_manager::unreg (io_watcher *w)
+template<class watcher>
+void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue)
 {
-  unsigned int sz = iow.size ();
-  unsigned int i = find (iow.begin (), iow.end (), w) - iow.begin ();
+  if (!iom_valid)
+    return;
 
-  if (i != sz)
+  if (w.active)
     {
-      if (sz == 1)
-        {
-          pfs.clear ();
-          iow.clear ();
-        }
-      else if (i == sz - 1)
-        {
-          iow.pop_back ();
-          pfs.pop_back ();
-        }
-      else
-        {
-          iow[i] = iow[sz - 1]; iow.pop_back ();
-          pfs[i] = pfs[sz - 1]; pfs.pop_back ();
-        }
+      queue [w.active - 1] = 0;
+      w.active = 0;
     }
 }
 
-void io_manager::reschedule_time_watchers ()
+#if IOM_TIME
+void time_watcher::trigger ()
 {
-  make_heap (tw.begin (), tw.end (), lowest_first);
+  call (*this);
+  io_manager::reg (*this);
 }
 
-void io_manager::reg (time_watcher *w)
-{
-  if (w->registered)
-    slog (L_CRIT, "FATAL: io_manager::reg(time_watcher) called on already-registered watcher");
+void io_manager::reg   (time_watcher &w)  { io_manager::reg   (w, tw); }
+void io_manager::unreg (time_watcher &w)  { io_manager::unreg (w, tw); }
+#endif
 
-  w->registered = true;
+#if IOM_IO
+void io_manager::reg   (io_watcher &w)    { io_manager::reg   (w, iow); }
+void io_manager::unreg (io_watcher &w)    { io_manager::unreg (w, iow); }
+#endif
 
-  tw.push_back (w);
-  push_heap (tw.begin (), tw.end (), lowest_first);
+#if IOM_CHECK
+void io_manager::reg   (check_watcher &w) { io_manager::reg   (w, cw); }
+void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); }
+#endif
+
+#if IOM_IDLE
+void io_manager::reg   (idle_watcher &w)  { io_manager::reg   (w, iw); }
+void io_manager::unreg (idle_watcher &w)  { io_manager::unreg (w, iw); }
+#endif
+
+#if IOM_SIG
+static void
+sighandler (int signum)
+{
+  sw [signum - 1]->pending = true;
+
+  // we use a pipe for signal notifications, as most current
+  // OSes (Linux...) do not implement pselect correctly. ugh.
+  char ch = signum; // actual content not used
+  write (sigpipe[1], &ch, 1);
 }
 
-void io_manager::unreg (time_watcher *w)
+void io_manager::reg (sig_watcher &w)
 {
-  if (w->registered)
+  assert (0 < w.signum);
+
+  sw.reserve (w.signum);
+
+  while (sw.size () < w.signum) // pathetic
+    sw.push_back (0);
+
+  sig_vec *&sv = sw[w.signum - 1];
+
+  if (!sv)
     {
-      unsigned int sz = tw.size ();
-      unsigned int i = find (tw.begin (), tw.end (), w) - tw.begin ();
+      sv = new sig_vec;
 
-      if (i != sz)
-        {
-          if (i != sz - 1)
-            tw[i] = tw[sz - 1];
+      sigaddset (&sigs, w.signum);
+      sigprocmask (SIG_BLOCK, &sigs, NULL);
+
+      struct sigaction sa;
+      sa.sa_handler = sighandler;
+      sigfillset (&sa.sa_mask);
+      sa.sa_flags = SA_RESTART;
 
-          tw.pop_back ();
-          reschedule_time_watchers ();
+      if (sigaction (w.signum, &sa, 0))
+        {
+          perror ("io_manager: error while installing signal handler, ignoring.");
+          abort ();
         }
 
-      w->registered = false;
     }
+
+  io_manager::reg (w, *sv);
 }
 
-inline void set_now (void)
+void io_manager::unreg (sig_watcher &w)
 {
-  struct timeval tv;
+  if (!w.active)
+    return;
 
-  gettimeofday (&tv, 0);
+  assert (0 < w.signum && w.signum <= sw.size ());
+  
+  io_manager::unreg (w, *sw[w.signum - 1]);
+}
 
-  NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000;
+void sig_watcher::start (int signum)
+{
+  stop ();
+  this->signum = signum;
+  io_manager::reg (*this);
 }
+#endif
 
 void io_manager::loop ()
 {
+  init::required ();
+
+#if IOM_TIME
   set_now ();
+#endif
 
   for (;;)
     {
-      while (tw[0]->at <= NOW)
-        {
-          // remove the first watcher
-          time_watcher *w = tw[0];
 
-          pop_heap (tw.begin (), tw.end (), lowest_first);
-          tw.pop_back ();
+#if IOM_TIME
+      // call pending time watchers
+      {
+        bool activity;
+
+        do
+          {
+            activity = false;
+
+            for (int i = tw.size (); i--; )
+              if (!tw[i])
+                tw.erase_unordered (i);
+              else if (tw[i]->at <= NOW)
+                {
+                  time_watcher &w = *tw[i];
+                  
+                  unreg (w);
+                  w.call (w);
 
-          w->registered = false;
+                  activity = true;
+                }
+          }
+        while (activity);
+      }
+#endif
+
+#if IOM_CHECK
+      // call all check watchers
+      for (int i = cw.size (); i--; )
+        if (!cw[i])
+          cw.erase_unordered (i);
+        else
+          cw[i]->call (*cw[i]);
+#endif
 
-          // call it
-          w->call (w->at);
+      struct TIMEVAL *to = 0;
+      struct TIMEVAL tval;
 
-          // re-add it if necessary
-          if (w->at >= 0 && !w->registered)
-            reg (w);
+#if IOM_IDLE
+      if (iw.size ())
+        {
+          tval.tv_sec  = 0;
+          tval.TV_FRAC = 0;
+          to = &tval;
         }
+      else
+#endif
+        {
+#if IOM_TIME
+          // find earliest active watcher
+          time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times
+
+          for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
+            if (*i && (*i)->at < next->at)
+              next = *i;
+
+          if (next->at > NOW && next != tw[0])
+            {
+              double diff = next->at - NOW;
+              tval.tv_sec  = (int)diff;
+              tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT);
+              to = &tval;
+            }
+        }
+#endif
 
-      int timeout = (int) ((tw[0]->at - NOW) * 1000);
+#if IOM_IO || IOM_SIG
+      fd_set rfd, wfd;
 
-      int fds = poll (&pfs[0], pfs.size (), timeout);
+      FD_ZERO (&rfd);
+      FD_ZERO (&wfd);
 
-      set_now ();
+      int fds = 0;
 
-      for (unsigned int i = iow.size (); fds > 0 && i--; )
-        if (pfs[i].revents)
+# if IOM_IO
+      for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); )
+        if (*i)
           {
-            --fds;
-            iow[i]->call (pfs[i].revents);
+            if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd);
+            if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd);
+
+            if ((*i)->fd >= fds) fds = (*i)->fd + 1;
           }
-    }
-}
+# endif
 
-void io_manager::idle_cb (tstamp &ts)
-{
-  ts = NOW + 86400; // wake up every day, for no good reason
-}
+      if (!to && !fds) //TODO: also check idle_watchers and check_watchers?
+        break; // no events
 
-io_manager::io_manager ()
-{
-  set_now ();
-  idle = new time_watcher (this, &io_manager::idle_cb);
-  idle->start (0);
-}
+# if IOM_SIG
+      FD_SET (sigpipe[0], &rfd);
+      if (sigpipe[0] >= fds) fds = sigpipe[0] + 1;
+# endif
+
+# if IOM_SIG
+      // there is no race, as we use a pipe for signals, so select
+      // will return if a signal is caught.
+      sigprocmask (SIG_UNBLOCK, &sigs, NULL);
+# endif
+      fds = select (fds, &rfd, &wfd, NULL, to);
+# if IOM_SIG
+      sigprocmask (SIG_BLOCK, &sigs, NULL);
+# endif
+
+# if IOM_TIME
+      {
+        // update time, try to compensate for gross non-monotonic time changes
+        tstamp diff = NOW;
+        set_now ();
+        diff = NOW - diff;
+
+        if (diff < 0)
+          for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); )
+            if (*i)
+              (*i)->at += diff;
+      }
+# endif
 
-io_manager::~io_manager ()
-{
-  //
+      if (fds > 0)
+        {
+# if IOM_SIG
+          if (FD_ISSET (sigpipe[0], &rfd))
+            {
+              char ch;
+
+              while (read (sigpipe[0], &ch, 1) > 0)
+                ;
+
+              for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); )
+                if (*svp && (*svp)->pending)
+                  {
+                    sig_vec &sv = **svp;
+                    for (int i = sv.size (); i--; )
+                      if (!sv[i])
+                        sv.erase_unordered (i);
+                      else
+                        sv[i]->call (*sv[i]);
+
+                    sv.pending = false;
+                  }
+            }
+# endif
+
+# if IOM_IO
+          for (int i = iow.size (); i--; )
+            if (!iow[i])
+              iow.erase_unordered (i);
+            else
+              {
+                io_watcher &w = *iow[i];
+                short revents = w.events;
+
+                if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ;
+                if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE;
+
+                if (revents)
+                  w.call (w, revents);
+              }
+#endif
+        }
+      else if (fds < 0 && errno != EINTR)
+        {
+          perror ("io_manager: fatal error while waiting for I/O or time event, aborting.");
+          abort ();
+        }
+#if IOM_IDLE
+      else
+        for (int i = iw.size (); i--; )
+          if (!iw[i])
+            iw.erase_unordered (i);
+          else
+            iw[i]->call (*iw[i]);
+#endif
+
+#elif IOM_TIME
+      if (!to)
+        break;
+
+      select (0, 0, 0, 0, &to);
+      set_now ();
+#else
+      break;
+#endif
+    }
 }