/builddir/build/BUILD/libassa-3.5.0/assa/Reactor.cpp

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00001 // -*- c++ -*-
00002 //------------------------------------------------------------------------------
00003 //                          Reactor.cpp
00004 //------------------------------------------------------------------------------
00005 //  Copyright (C) 1997-2002,2005-2007  Vladislav Grinchenko
00006 //
00007 //  This library is free software; you can redistribute it and/or
00008 //  modify it under the terms of the GNU Library General Public
00009 //  License as published by the Free Software Foundation; either
00010 //  version 2 of the License, or (at your option) any later version.
00011 //----------------------------------------------------------------------------- 
00012 //  Created: 05/25/1999
00013 //----------------------------------------------------------------------------- 
00014 #include <iostream>
00015 #include <sstream>
00016 #include <string>
00017 
00018 #include "assa/Reactor.h"
00019 #include "assa/Logger.h"
00020 
00021 using namespace ASSA;
00022 
00023 Reactor::
00024 Reactor () : 
00025     m_fd_setsize  (1024), 
00026     m_maxfd_plus1 (0), 
00027     m_active      (true)
00028 {
00029     trace_with_mask("Reactor::Reactor",REACTTRACE);
00030 
00034 #if defined(WIN32)
00035     m_fd_setsize = FD_SETSIZE;
00036 
00037 #else  // POSIX
00038     struct rlimit rlim;
00039     rlim.rlim_max = 0;
00040 
00041     if ( getrlimit (RLIMIT_NOFILE, &rlim) == 0 ) {
00042         m_fd_setsize = rlim.rlim_cur;
00043     }
00044 #endif
00045 
00048 #if defined (WIN32)             
00049     WSADATA data;
00050     WSAStartup (MAKEWORD (2, 2), &data);
00051 #endif
00052 }
00053 
00054 Reactor::
00055 ~Reactor()
00056 {   
00057     trace_with_mask("Reactor::~Reactor",REACTTRACE);
00058 
00059     m_readSet.clear   ();
00060     m_writeSet.clear  ();
00061     m_exceptSet.clear ();
00062     deactivate ();
00063 }
00064 
00065 TimerId
00066 Reactor::
00067 registerTimerHandler (EventHandler*      eh_, 
00068                       const TimeVal&     timeout_,
00069                       const std::string& name_)
00070 {
00071     trace_with_mask( "Reactor::registerTimerHandler",REACTTRACE);
00072     Assure_return (eh_);
00073 
00074     TimeVal now (TimeVal::gettimeofday());
00075     TimeVal t (now + timeout_);
00076 
00077     DL((REACT,"TIMEOUT_EVENT......: (%d,%d)\n",  
00078         timeout_.sec(),timeout_.msec()));
00079     DL((REACT,"Time now...........: %s\n", now.fmtString().c_str() ));
00080     DL((REACT,"Scheduled to expire: %s\n", t.fmtString().c_str() ));
00081 
00082     TimerId tid =  m_tqueue.insert (eh_, t, timeout_, name_);
00083 
00084     DL((REACT,"---Modified Timer Queue----\n"));
00085     m_tqueue.dump();
00086     DL((REACT,"---------------------------\n"));
00087 
00088     return (tid);
00089 }
00090 
00091 bool 
00092 Reactor::
00093 registerIOHandler (EventHandler* eh_, handler_t fd_, EventType et_)
00094 {
00095     trace_with_mask("Reactor::registerHandler(I/O)",REACTTRACE);
00096 
00097     std::ostringstream msg;
00098     Assure_return (eh_ && !isSignalEvent (et_) && !isTimeoutEvent (et_));
00099 
00100     if (isReadEvent (et_)) 
00101     {
00102         if (!m_waitSet.m_rset.setFd (fd_)) 
00103         {
00104             DL((ASSAERR,"readset: fd %d out of range\n", fd_));
00105             return (false);
00106         }
00107         m_readSet[fd_] = eh_;
00108         msg << "READ_EVENT";
00109     }
00110 
00111     if (isWriteEvent (et_)) 
00112     {
00113         if (!m_waitSet.m_wset.setFd (fd_)) 
00114         {
00115             DL((ASSAERR,"writeset: fd %d out of range\n", fd_));
00116             return (false);
00117         }
00118         m_writeSet[fd_] = eh_;
00119         msg << " WRITE_EVENT";
00120     }
00121 
00122     if (isExceptEvent (et_)) 
00123     {
00124         if (!m_waitSet.m_eset.setFd (fd_)) 
00125         {
00126             DL((ASSAERR,"exceptset: fd %d out of range\n", fd_));
00127             return (false);
00128         }
00129         m_exceptSet[fd_] = eh_;
00130         msg << " EXCEPT_EVENT";
00131     }
00132     msg << std::ends;
00133 
00134     DL((REACT,"Registered EvtH(%s) fd=%d (0x%x) for event(s) %s\n", 
00135         eh_->get_id ().c_str (), fd_, (u_long)eh_, msg.str ().c_str () ));
00136 
00137 #if !defined (WIN32)
00138     if (m_maxfd_plus1 < fd_+1) {
00139         m_maxfd_plus1 = fd_+1;
00140         DL((REACT,"maxfd+1 adjusted to %d\n", m_maxfd_plus1));
00141     }
00142 #endif
00143 
00144     DL((REACT,"Modified waitSet:\n"));
00145     m_waitSet.dump ();
00146 
00147     return (true);
00148 }
00149 
00150 bool 
00151 Reactor::
00152 removeTimerHandler (TimerId tid_)
00153 {
00154     trace_with_mask("Reactor::removeTimer",REACTTRACE);
00155     bool ret;
00156 
00157     if ((ret = m_tqueue.remove (tid_))) {
00158         DL((REACT,"---Modified Timer Queue----\n"));
00159         m_tqueue.dump();
00160         DL((REACT,"---------------------------\n"));
00161     }
00162     else {
00163         EL((ASSAERR,"Timer tid 0x%x wasn't found!\n", (u_long)tid_ ));
00164     }
00165     return (ret);
00166 }
00167 
00171 bool 
00172 Reactor::
00173 removeHandler (EventHandler* eh_, EventType event_)
00174 {
00175     trace_with_mask("Reactor::removeHandler(eh_,et_)",REACTTRACE);
00176 
00177     bool ret = false;
00178     handler_t fd;
00179     Fd2Eh_Map_Iter iter;
00180 
00181     if (eh_ == NULL) {
00182         return false;
00183     }
00184 
00185     if (isTimeoutEvent (event_)) {
00186         ret = m_tqueue.remove (eh_);
00187         ret = true;
00188     }
00189 
00190     if (isReadEvent (event_)) {
00191         iter = m_readSet.begin ();
00192         while (iter != m_readSet.end ()) {
00193             if ((*iter).second == eh_) {
00194                 fd = (*iter).first;
00195                 m_readSet.erase (iter);
00196                 m_waitSet.m_rset.clear (fd);
00197                 ret = true;
00198                 break;
00199             }
00200             iter++;
00201         }
00202     } 
00203     
00204     if (isWriteEvent (event_)) {
00205         iter = m_writeSet.begin ();
00206         while (iter != m_writeSet.end ()) {
00207             if ((*iter).second == eh_) {
00208                 fd = (*iter).first;
00209                 m_writeSet.erase (iter);
00210                 m_waitSet.m_wset.clear (fd);
00211                 ret = true;
00212                 break;
00213             }
00214             iter++;
00215         }
00216     }
00217 
00218     if (isExceptEvent (event_)) {
00219         iter = m_exceptSet.begin ();
00220         while (iter != m_exceptSet.end ()) {
00221             if ((*iter).second == eh_) {
00222                 fd = (*iter).first;
00223                 m_exceptSet.erase (iter);
00224                 m_waitSet.m_eset.clear (fd);
00225                 ret = true;
00226                 break;
00227             }
00228             iter++;
00229         }
00230     }
00231 
00232     if (ret == true) {
00233         DL((REACT,"Found EvtH \"%s\"(%p)\n", eh_->get_id ().c_str (), eh_));
00234         eh_->handle_close (fd);
00235     }
00236 
00237     adjust_maxfdp1 (fd);
00238 
00239     DL((REACT,"Modifies waitSet:\n"));
00240     m_waitSet.dump ();
00241 
00242     return (ret);
00243 }
00244 
00245 bool
00246 Reactor::
00247 removeIOHandler (handler_t fd_)
00248 {
00249     trace_with_mask("Reactor::removeIOHandler",REACTTRACE);
00250 
00251     bool ret = false;
00252     EventHandler*  ehp = NULL;
00253     Fd2Eh_Map_Iter iter;
00254 
00255     Assure_return (ASSA::is_valid_handler (fd_));
00256 
00257     DL((REACT,"Removing handler for fd=%d\n",fd_));
00258 
00263     if ((iter = m_readSet.find (fd_)) != m_readSet.end ()) 
00264     {
00265         ehp = (*iter).second;
00266         m_readSet.erase (iter);
00267         m_waitSet.m_rset.clear (fd_);
00268         m_readySet.m_rset.clear (fd_);
00269         if (m_readSet.size () > 0) {
00270             iter = m_readSet.end ();
00271             iter--;
00272         }
00273         ret = true;
00274     }
00275 
00276     if ((iter = m_writeSet.find (fd_)) != m_writeSet.end ()) 
00277     {
00278         ehp = (*iter).second;
00279         m_writeSet.erase (iter);
00280         m_waitSet.m_wset.clear (fd_);
00281         m_readySet.m_wset.clear (fd_);
00282         if (m_writeSet.size () > 0) {
00283             iter = m_writeSet.end ();
00284             iter--;
00285         }
00286         ret = true;
00287     }
00288 
00289     if ((iter = m_exceptSet.find (fd_)) != m_exceptSet.end ()) 
00290     {
00291         ehp = (*iter).second;
00292         m_exceptSet.erase (iter);
00293         m_waitSet.m_eset.clear (fd_);
00294         m_readySet.m_eset.clear (fd_);
00295         if (m_exceptSet.size () > 0) {
00296             iter = m_exceptSet.end ();
00297             iter--;
00298         }
00299         ret = true;
00300     }
00301 
00302     if (ret == true && ehp != NULL) {
00303         DL((REACT,"Removed EvtH \"%s\"(%p)\n", ehp->get_id ().c_str (), ehp));
00304         ehp->handle_close (fd_);
00305     }
00306 
00307     adjust_maxfdp1 (fd_);
00308 
00309     DL((REACT,"Modifies waitSet:\n"));
00310     m_waitSet.dump ();
00311 
00312     return (ret);
00313 }
00314 
00315 bool
00316 Reactor::
00317 checkFDs (void)
00318 {
00319     trace_with_mask("Reactor::checkFDs",REACTTRACE);
00320     
00321     bool num_removed = false;
00322     FdSet mask;
00323     timeval poll = { 0, 0 };
00324 
00325     for (handler_t fd = 0; fd < m_fd_setsize; fd++) {
00326         if ( m_readSet[fd] != NULL ) {
00327             mask.setFd (fd);
00328             if ( ::select (fd+1, &mask, NULL, NULL, &poll) < 0 ) {
00329                 removeIOHandler (fd);
00330                 num_removed = true;
00331                 DL((REACT,"Detected BAD FD: %d\n", fd ));
00332             }
00333             mask.clear (fd);
00334         }
00335     }
00336     return (num_removed);
00337 }
00338 
00339 bool
00340 Reactor::
00341 handleError (void)
00342 {
00343     trace_with_mask("Reactor::handleError",REACTTRACE);
00344 
00347     if ( !m_active ) {
00348         DL((REACT,"Received cmd to stop Reactor\n"));
00349         return (false);
00350     }
00351 
00352     /*---
00353       TODO: If select(2) returns before time expires, with
00354       a descriptor ready or with EINTR, timeval is not
00355       going to be updated with number of seconds remaining.
00356       This is true for all systems except Linux, which will
00357       do so. Therefore, to restart correctly in case of
00358       EINTR, we ought to take time measurement before and
00359       after select, and try to select() for remaining time.
00360     
00361       For now, we restart with the initial timing value.
00362       ---*/
00363     /*---
00364       BSD kernel never restarts select(2). SVR4 will restart if
00365       the SA_RESTART flag is specified when the signal handler
00366       for the signal delivered is installed. This means taht for
00367       portability, we must handle signal interrupts.
00368       ---*/
00369 
00370     if ( errno == EINTR ) {
00371         EL((REACT,"EINTR: interrupted select(2)\n"));
00372         /*
00373           If I was sitting in select(2) and received SIGTERM,
00374           the signal handler would have set m_active to 'false',
00375           and this function would have returned 'false' as above.
00376           For any other non-critical signals (USR1,...),
00377           we retry select.
00378         */
00379         return (true);
00380     }
00381     /*
00382       EBADF - bad file number. One of the file descriptors does
00383       not reference an open file to open(), close(), ioctl().
00384       This can happen if user closed fd and forgot to remove
00385       handler from Reactor.
00386     */
00387     if ( errno == EBADF ) {
00388         DL((REACT,"EBADF: bad file descriptor\n"));
00389         return (checkFDs ());
00390     }
00391     /*
00392       Any other error from select
00393     */
00394 #if defined (WIN32) 
00395     DL ((REACT,"select(3) error = %d\n", WSAGetLastError()));
00396 #else
00397     EL((ASSAERR,"select(3) error\n"));
00398 #endif
00399     return (false);
00400 }
00401 
00402 int
00403 Reactor::
00404 isAnyReady (void)
00405 {
00406     trace_with_mask("Reactor::isAnyReady",REACTTRACE);
00407 
00408     int n = m_readySet.m_rset.numSet () +
00409         m_readySet.m_wset.numSet () +
00410         m_readySet.m_eset.numSet ();
00411 
00412     if ( n > 0 ) {
00413         DL((REACT,"m_readySet: %d FDs are ready for processing\n", n));
00414         m_readySet.dump ();
00415     }
00416     return (n);
00417 }
00418 
00419 void 
00420 Reactor::
00421 calculateTimeout (TimeVal*& howlong_, TimeVal* maxwait_)
00422 {
00423     trace_with_mask("Reactor::calculateTimeout",REACTTRACE);
00424 
00425     TimeVal now;
00426     TimeVal tv;
00427 
00428     if (m_tqueue.isEmpty () ) {
00429         howlong_ = maxwait_;
00430         goto done;
00431     }
00432     now = TimeVal::gettimeofday ();
00433     tv = m_tqueue.top ();
00434     
00435     if (tv < now) {
00436         /*--- 
00437           It took too long to get here (fraction of a millisecond), 
00438           and top timer had already expired. In this case,
00439           perform non-blocking select in order to drain the timer queue.
00440           ---*/
00441         *howlong_ = 0;
00442     }
00443     else {  
00444         DL((REACT,"--------- Timer Queue ----------\n"));
00445         m_tqueue.dump();
00446         DL((REACT,"--------------------------------\n"));
00447 
00448         if (maxwait_ == NULL || *maxwait_ == TimeVal::zeroTime ()) {
00449             *howlong_ = tv - now;
00450         }
00451         else {
00452             *howlong_ = (*maxwait_+now) < tv ? *maxwait_ : tv-now;
00453         }
00454     }
00455 
00456  done:
00457     if (howlong_ != NULL) {
00458         DL((REACT,"delay (%f)\n", double (*howlong_) ));
00459     }
00460     else {
00461         DL((REACT,"delay (forever)\n"));
00462     }
00463 }
00464 
00468 void
00469 Reactor::
00470 waitForEvents (void)
00471 {
00472     while ( m_active ) {
00473         waitForEvents ((TimeVal*) NULL);
00474     }
00475 }
00476 
00493 void
00494 Reactor::
00495 waitForEvents (TimeVal* tv_)
00496 {
00497     trace_with_mask("Reactor::waitForEvents",REACTTRACE);
00498 
00499     TimerCountdown traceTime (tv_);
00500     DL((REACT,"======================================\n"));
00501 
00502     /*--- Expire all stale Timers ---*/
00503     m_tqueue.expire (TimeVal::gettimeofday ());
00504 
00505     /* Test to see if Reactor has been deactivated as a result
00506      * of processing done by any TimerHandlers.
00507      */
00508     if (!m_active) {
00509         return;
00510     }
00511 
00512     int      nReady;
00513     TimeVal  delay;
00514     TimeVal* dlp = &delay;
00515 
00516     /*---
00517       In case if not all data have been processed by the EventHandler,
00518       and EventHandler stated so in its callback's return value
00519       to dispatcher (), it will be called again. This way 
00520       underlying file/socket stream can efficiently utilize its
00521       buffering mechaninsm.
00522       ---*/
00523     if ((nReady = isAnyReady ())) {
00524         DL((REACT,"isAnyReady returned: %d\n",nReady));
00525         dispatch (nReady);
00526         return;
00527     }
00528 
00529     DL((REACT,"=== m_waitSet ===\n"));
00530     m_waitSet.dump ();
00531 
00532     do {
00533         m_readySet.reset ();
00534         DL ((REACT,"m_readySet after reset():\n"));
00535         m_readySet.dump ();
00536 
00537         m_readySet = m_waitSet;
00538         DL ((REACT,"m_readySet after assign:\n"));
00539         m_readySet.dump ();
00540 
00541         calculateTimeout (dlp, tv_);
00542 
00543         nReady = ::select (m_maxfd_plus1, 
00544                            &m_readySet.m_rset,
00545                            &m_readySet.m_wset, 
00546                            &m_readySet.m_eset, 
00547                            dlp);
00548         DL((REACT,"::select() returned: %d\n",nReady));
00549 
00550         m_readySet.sync ();
00551         DL ((REACT,"m_readySet after select:\n"));
00552         m_readySet.dump ();
00553 
00554     } 
00555     while (nReady < 0 && handleError ());
00556 
00557     dispatch (nReady);
00558 }
00559 
00566 void 
00567 Reactor::
00568 dispatchHandler (FdSet& mask_, Fd2Eh_Map_Type& fdSet_, EH_IO_Callback callback_)
00569 {
00570     trace_with_mask("Reactor::dispatchHandler",REACTTRACE);
00571 
00572     int ret = 0;
00573     handler_t fd;
00574     EventHandler* ehp = NULL;
00575     std::string eh_id;
00576 
00577     Fd2Eh_Map_Iter iter = fdSet_.begin ();
00578 
00579     while (iter != fdSet_.end ()) 
00580     {
00581         fd  = (*iter).first;
00582         ehp = (*iter).second;
00583 
00584         if (mask_.isSet (fd) && ehp != NULL) 
00585         {
00586             eh_id = ehp->get_id ();
00587             DL((REACT,"Data detected from \"%s\"(fd=%d)\n",
00588                 eh_id.c_str (), fd));
00589 
00590             ret = (ehp->*callback_) (fd); /* Fire up a callback */
00591 
00592             if (ret == -1) {
00593                 removeIOHandler (fd);
00594             }
00595             else if (ret > 0) {
00596                 DL((REACT,"%d bytes pending on fd=%d \"%s\"\n",
00597                     ret, fd, eh_id.c_str ()));
00598                 //return;   <-- would starve other connections
00599             }
00600             else {
00601                 DL((REACT,"All data from \"%s\"(fd=%d) are consumed\n", 
00602                     eh_id.c_str (), fd));
00603                 mask_.clear (fd);
00604             }
00611             iter = fdSet_.begin ();
00612         }
00613         else {
00614             iter++;
00615         }
00616     }
00617 }
00618 
00624 bool
00625 Reactor::
00626 dispatch (int ready_)
00627 {
00628     trace_with_mask("Reactor::dispatch", REACTTRACE);
00629 
00630     m_tqueue.expire (TimeVal::gettimeofday ());
00631 
00632     if ( ready_ < 0 ) 
00633     {
00634 #if !defined (WIN32)
00635         EL((ASSAERR,"::select(3) error\n"));
00636 #endif
00637         return (false);
00638     }
00639     if ( ready_ == 0 ) {
00640         return (true);
00641     }
00642 
00643     DL((REACT,"Dispatching %d FDs.\n",ready_));
00644     DL((REACT,"m_readySet:\n"));
00645     m_readySet.dump ();
00646 
00647     /*--- Writes first ---*/
00648     dispatchHandler (m_readySet.m_wset, 
00649                      m_writeSet, 
00650                      &EventHandler::handle_write);
00651 
00652     /*--- Exceptions next ---*/
00653     dispatchHandler (m_readySet.m_eset, 
00654                      m_exceptSet, 
00655                      &EventHandler::handle_except);
00656 
00657     /*--- Finally, the Reads ---*/
00658     dispatchHandler (m_readySet.m_rset, 
00659                      m_readSet, 
00660                      &EventHandler::handle_read);
00661 
00662     return (true);
00663 }
00664 
00665 void 
00666 Reactor::
00667 stopReactor (void) 
00668 { 
00669     trace_with_mask("Reactor::stopReactor", REACTTRACE);
00670 
00671     m_active = false; 
00672 
00673     Fd2Eh_Map_Iter iter;
00674     EventHandler* ehp;
00675 
00676     while (m_readSet.size () > 0) {
00677         iter = m_readSet.begin ();
00678         ehp = (*iter).second;
00679         removeHandler (ehp);
00680     }
00681 
00682     while (m_writeSet.size () > 0) {
00683         iter = m_writeSet.begin ();
00684         ehp = (*iter).second;
00685         removeHandler (ehp);
00686     }
00687 
00688     while (m_exceptSet.size () > 0) {
00689         iter = m_exceptSet.begin ();
00690         ehp = (*iter).second;
00691         removeHandler (ehp);
00692     }
00693 }
00694 
00699 void
00700 Reactor::
00701 adjust_maxfdp1 (handler_t fd_)
00702 {
00703 #if !defined (WIN32)  /* POSIX */
00704 
00705     trace_with_mask("Reactor::adjust_maxfdp1", REACTTRACE);
00706 
00707     if (m_maxfd_plus1 == fd_ + 1) 
00708     {
00709         m_maxfd_plus1 = m_waitSet.max_fd () + 1;
00710         DL((REACT,"maxfd+1 adjusted to %d\n", m_maxfd_plus1));
00711     }
00712 #endif
00713 }

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