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/* |
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iom.C -- generic I/O multiplexer |
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Copyright (C) 2003-2006 Marc Lehmann <gvpe@schmorp.de> |
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|
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This file is part of GVPE. |
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|
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GVPE is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with gvpe; if not, write to the Free Software |
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Foundation, Inc. 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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|
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#include "iom.h" |
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|
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#include <cstdio> |
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#include <cstdlib> |
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#include <cerrno> |
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#include <cassert> |
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|
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#include <sys/types.h> |
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#include <sys/time.h> |
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|
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#if 1 // older unices need these includes for select (2) |
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# include <unistd.h> |
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# include <time.h> |
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#endif |
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|
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#if IOM_CHILD |
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# include <sys/wait.h> |
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#endif |
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|
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#if IOM_SIG |
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# include <csignal> |
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# include <fcntl.h> |
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#endif |
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|
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// if the BSDs would at least be marginally POSIX-compatible.. *sigh* |
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// until that happens, sys/select.h must come last |
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#include <sys/select.h> |
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|
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#define TIMEVAL timeval |
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#define TV_FRAC tv_usec |
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#define TV_MULT 1000000L |
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|
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#if IOM_CHECK |
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static io_manager_vec<check_watcher> cw; |
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#endif |
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#if IOM_IDLE |
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static io_manager_vec<idle_watcher> iw; |
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#endif |
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|
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#if IOM_SIG |
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static int sigpipe[2]; // signal signalling pipe |
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static sigset_t sigs; |
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struct sig_vec : io_manager_vec<sig_watcher> { |
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int pending; |
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sig_vec () |
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: pending (false) |
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{ } |
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}; |
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static vector<sig_vec *> sw; |
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#endif |
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|
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#if IOM_CHILD |
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static io_manager_vec<child_watcher> pw; |
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#endif |
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|
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#ifdef IOM_LIBEVENT |
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static bool need_set_now; // need to set_now in callback |
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#else |
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#if IOM_IO |
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static io_manager_vec<io_watcher> iow; |
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#endif |
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#if IOM_TIME |
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static io_manager_vec<time_watcher> tw; |
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#endif |
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#endif |
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|
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#if IOM_TIME |
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tstamp io_manager::now () |
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{ |
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struct timeval tv; |
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|
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gettimeofday (&tv, 0); |
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return (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000.; |
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} |
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|
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void io_manager::set_now () |
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{ |
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NOW = now (); |
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#ifdef IOM_LIBEVENT |
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need_set_now = false; |
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#endif |
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} |
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#endif |
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|
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#ifndef IOM_LIBEVENT |
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// this is a dummy time watcher to ensure that the first |
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// time watcher is _always_ valid, this gets rid of a lot |
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// of null-pointer-checks |
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// (must come _before_ iom is being defined) |
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static struct tw0 : time_watcher |
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{ |
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void cb (time_watcher &w) |
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{ |
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// should never get called |
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// reached end-of-time, or tstamp has a bogus definition, |
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// or compiler initialisation order broken, or something else :) |
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abort (); |
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} |
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|
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tw0 () |
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: time_watcher (this, &tw0::cb) |
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{ } |
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} tw0; |
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#endif |
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|
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tstamp NOW; |
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|
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#if IOM_CHILD |
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// sig_watcher for child signal(s) |
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static struct sw0 : sig_watcher |
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{ |
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void cb (sig_watcher &w) |
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{ |
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// SIGCHLD, call corresponding watchera |
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pid_t pid; |
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int status; |
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|
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while ((pid = waitpid (-1, &status, WNOHANG)) > 0) |
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for (int i = pw.size (); i--; ) |
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{ |
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child_watcher *w = pw[i]; |
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|
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if (!w) |
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pw.erase_unordered (i); |
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else if (w->pid == pid) |
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{ |
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io_manager::unreg (*w); |
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w->call (*w, status); |
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} |
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} |
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} |
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|
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sw0 () |
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: sig_watcher (this, &sw0::cb) |
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{ } |
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} sw0; |
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#endif |
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|
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static bool iom_valid; |
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|
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// used for initialisation only |
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static struct init { |
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init () |
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{ |
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#ifdef IOM_PREINIT |
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{ IOM_PREINIT } |
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#endif |
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|
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#ifdef IOM_LIBEVENT |
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event_init (); |
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#endif |
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iom_valid = true; |
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|
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#if IOM_SIG |
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sigemptyset (&sigs); |
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|
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if (pipe (sigpipe)) |
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{ |
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perror ("io_manager: unable to create signal pipe, aborting."); |
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abort (); |
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} |
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|
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fcntl (sigpipe[0], F_SETFL, O_NONBLOCK); fcntl (sigpipe[0], F_SETFD, FD_CLOEXEC); |
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fcntl (sigpipe[1], F_SETFL, O_NONBLOCK); fcntl (sigpipe[1], F_SETFD, FD_CLOEXEC); |
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#endif |
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|
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#if IOM_CHILD |
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sw0.start (SIGCHLD); |
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#endif |
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|
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#if IOM_TIME |
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io_manager::set_now (); |
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|
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#ifndef IOM_LIBEVENT |
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tw0.start (TSTAMP_MAX); |
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#endif |
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#endif |
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|
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#ifdef IOM_POSTINIT |
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{ IOM_POSTINIT } |
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#endif |
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} |
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|
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~init () |
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{ |
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iom_valid = false; |
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} |
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|
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static void required (); |
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} init; |
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|
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void |
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init::required () |
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{ |
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if (!iom_valid) |
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{ |
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write (2, "io_manager: early registration attempt, aborting.\n", |
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sizeof ("io_manager: early registration attempt, aborting.\n") - 1); |
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abort (); |
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} |
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} |
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|
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template<class watcher> |
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void io_manager::reg (watcher &w, io_manager_vec<watcher> &queue) |
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{ |
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init::required (); |
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|
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if (!w.active) |
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{ |
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queue.push_back (&w); |
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w.active = queue.size (); |
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} |
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} |
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|
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template<class watcher> |
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void io_manager::unreg (watcher &w, io_manager_vec<watcher> &queue) |
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{ |
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if (!iom_valid) |
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return; |
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|
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if (w.active) |
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{ |
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queue [w.active - 1] = 0; |
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w.active = 0; |
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} |
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} |
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|
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#if IOM_TIME |
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#ifdef IOM_LIBEVENT |
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void iom_time_c_callback (int fd, short events, void *data) |
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{ |
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if (need_set_now) io_manager::set_now (); |
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time_watcher *w = static_cast<time_watcher *>(data); |
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w->call (*w); |
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} |
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|
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void time_watcher::start () |
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{ |
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stop (); |
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evtimer_set (&ev, iom_time_c_callback, (void *)this); |
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struct timeval tv; |
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tv.tv_sec = (long)at; |
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tv.tv_usec = (long)((at - (tstamp)tv.tv_sec) * 1000000.); |
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evtimer_add (&ev, &tv); |
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active = 1; |
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} |
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#else |
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void io_manager::reg (time_watcher &w) { io_manager::reg (w, tw); } |
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void io_manager::unreg (time_watcher &w) { io_manager::unreg (w, tw); } |
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#endif |
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|
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void time_watcher::trigger () |
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{ |
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call (*this); |
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start (); |
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} |
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#endif |
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|
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#if IOM_IO |
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#ifdef IOM_LIBEVENT |
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void iom_io_c_callback (int fd, short events, void *data) |
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{ |
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if (need_set_now) io_manager::set_now (); |
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io_watcher *w = static_cast<io_watcher *>(data); |
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w->call (*w, events); |
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} |
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|
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void io_watcher::set (int fd_, short events_) |
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{ |
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if (active) event_del (&ev); |
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fd = fd_; |
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events = events_; |
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event_set (&ev, fd_, events_ | EV_PERSIST, iom_io_c_callback, (void *)this); |
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if (active) event_add (&ev, 0); |
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} |
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#else |
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void io_manager::reg (io_watcher &w) { io_manager::reg (w, iow); } |
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void io_manager::unreg (io_watcher &w) { io_manager::unreg (w, iow); } |
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#endif |
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#endif |
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|
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#if IOM_CHECK |
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void io_manager::reg (check_watcher &w) { io_manager::reg (w, cw); } |
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void io_manager::unreg (check_watcher &w) { io_manager::unreg (w, cw); } |
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#endif |
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|
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#if IOM_IDLE |
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void io_manager::reg (idle_watcher &w) { io_manager::reg (w, iw); } |
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void io_manager::unreg (idle_watcher &w) { io_manager::unreg (w, iw); } |
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#endif |
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|
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#if IOM_SIG |
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static void |
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sighandler (int signum) |
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{ |
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sw [signum - 1]->pending = true; |
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|
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// we use a pipe for signal notifications, as most current |
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// OSes (Linux...) do not implement pselect correctly. ugh. |
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char ch = signum; // actual content not used |
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write (sigpipe[1], &ch, 1); |
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} |
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|
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void io_manager::reg (sig_watcher &w) |
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{ |
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init::required (); |
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|
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assert (0 < w.signum); |
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|
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sw.reserve (w.signum); |
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|
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while (sw.size () < w.signum) // pathetic |
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sw.push_back (0); |
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|
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sig_vec *&sv = sw[w.signum - 1]; |
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|
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if (!sv) |
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{ |
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sv = new sig_vec; |
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|
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sigaddset (&sigs, w.signum); |
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sigprocmask (SIG_BLOCK, &sigs, NULL); |
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|
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struct sigaction sa; |
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sa.sa_handler = sighandler; |
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sigfillset (&sa.sa_mask); |
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sa.sa_flags = SA_RESTART; |
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|
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if (sigaction (w.signum, &sa, 0)) |
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{ |
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perror ("io_manager: error while installing signal handler, ignoring."); |
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abort (); |
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} |
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|
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} |
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|
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io_manager::reg (w, *sv); |
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} |
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|
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void io_manager::unreg (sig_watcher &w) |
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{ |
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if (!w.active || !iom_valid) |
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return; |
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|
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assert (0 < w.signum && w.signum <= sw.size ()); |
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|
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io_manager::unreg (w, *sw[w.signum - 1]); |
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} |
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|
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void sig_watcher::start (int signum) |
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{ |
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stop (); |
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this->signum = signum; |
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io_manager::reg (*this); |
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} |
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#endif |
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|
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#if IOM_CHILD |
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void io_manager::reg (child_watcher &w) { io_manager::reg (w, pw); } |
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void io_manager::unreg (child_watcher &w) { io_manager::unreg (w, pw); } |
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#endif |
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|
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void io_manager::loop () |
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{ |
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init::required (); |
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|
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#if IOM_TIME |
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set_now (); |
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#endif |
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|
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for (;;) |
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{ |
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#ifndef IOM_LIBEVENT |
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#if IOM_TIME |
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// call pending time watchers |
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{ |
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bool activity; |
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|
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do |
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{ |
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activity = false; |
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|
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for (int i = tw.size (); i--; ) |
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if (!tw[i]) |
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tw.erase_unordered (i); |
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else if (tw[i]->at <= NOW) |
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{ |
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time_watcher &w = *tw[i]; |
410 |
|
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unreg (w); |
412 |
w.call (w); |
413 |
|
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activity = true; |
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} |
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} |
417 |
while (activity); |
418 |
} |
419 |
#endif |
420 |
#endif |
421 |
|
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#if IOM_CHECK |
423 |
// call all check watchers |
424 |
for (int i = cw.size (); i--; ) |
425 |
if (!cw[i]) |
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cw.erase_unordered (i); |
427 |
else |
428 |
cw[i]->call (*cw[i]); |
429 |
#endif |
430 |
|
431 |
struct TIMEVAL *to = 0; |
432 |
struct TIMEVAL tval; |
433 |
|
434 |
#if IOM_IDLE |
435 |
if (iw.size ()) |
436 |
{ |
437 |
tval.tv_sec = 0; |
438 |
tval.TV_FRAC = 0; |
439 |
to = &tval; |
440 |
} |
441 |
else |
442 |
#endif |
443 |
{ |
444 |
#ifndef IOM_LIBEVENT |
445 |
#if IOM_TIME |
446 |
// find earliest active watcher |
447 |
time_watcher *next = tw[0]; // the first time-watcher must exist at ALL times |
448 |
|
449 |
for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); ) |
450 |
if (*i && (*i)->at < next->at) |
451 |
next = *i; |
452 |
|
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if (next->at > NOW && next != tw[0]) |
454 |
{ |
455 |
double diff = next->at - NOW; |
456 |
tval.tv_sec = (int)diff; |
457 |
tval.TV_FRAC = (int) ((diff - tval.tv_sec) * TV_MULT); |
458 |
to = &tval; |
459 |
} |
460 |
#endif |
461 |
#endif |
462 |
} |
463 |
|
464 |
#ifndef IOM_LIBEVENT |
465 |
#if IOM_IO || IOM_SIG |
466 |
fd_set rfd, wfd; |
467 |
|
468 |
FD_ZERO (&rfd); |
469 |
FD_ZERO (&wfd); |
470 |
|
471 |
int fds = 0; |
472 |
|
473 |
#if IOM_IO |
474 |
for (io_manager_vec<io_watcher>::const_iterator i = iow.end (); i-- > iow.begin (); ) |
475 |
if (*i) |
476 |
{ |
477 |
if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); |
478 |
if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); |
479 |
|
480 |
if ((*i)->fd >= fds) fds = (*i)->fd + 1; |
481 |
} |
482 |
#endif |
483 |
|
484 |
if (!to && !fds) //TODO: also check idle_watchers and check_watchers? |
485 |
break; // no events |
486 |
|
487 |
#if IOM_SIG |
488 |
FD_SET (sigpipe[0], &rfd); |
489 |
if (sigpipe[0] >= fds) fds = sigpipe[0] + 1; |
490 |
#endif |
491 |
|
492 |
#if IOM_SIG |
493 |
// there is no race, as we use a pipe for signals, so select |
494 |
// will return if a signal is caught. |
495 |
sigprocmask (SIG_UNBLOCK, &sigs, NULL); |
496 |
#endif |
497 |
fds = select (fds, &rfd, &wfd, NULL, to); |
498 |
#if IOM_SIG |
499 |
sigprocmask (SIG_BLOCK, &sigs, NULL); |
500 |
#endif |
501 |
#elif IOM_TIME |
502 |
if (!to) |
503 |
break; |
504 |
|
505 |
select (0, 0, 0, 0, to); |
506 |
#endif |
507 |
|
508 |
#if IOM_TIME |
509 |
{ |
510 |
// update time, try to compensate for gross non-monotonic time changes |
511 |
tstamp diff = NOW; |
512 |
set_now (); |
513 |
diff = NOW - diff; |
514 |
|
515 |
if (diff < 0) |
516 |
for (io_manager_vec<time_watcher>::const_iterator i = tw.end (); i-- > tw.begin (); ) |
517 |
if (*i) |
518 |
(*i)->at += diff; |
519 |
} |
520 |
#endif |
521 |
|
522 |
if (fds > 0) |
523 |
{ |
524 |
#if IOM_SIG |
525 |
if (FD_ISSET (sigpipe[0], &rfd)) |
526 |
{ |
527 |
char ch; |
528 |
|
529 |
while (read (sigpipe[0], &ch, 1) > 0) |
530 |
; |
531 |
|
532 |
for (vector<sig_vec *>::iterator svp = sw.end (); svp-- > sw.begin (); ) |
533 |
if (*svp && (*svp)->pending) |
534 |
{ |
535 |
sig_vec &sv = **svp; |
536 |
for (int i = sv.size (); i--; ) |
537 |
if (!sv[i]) |
538 |
sv.erase_unordered (i); |
539 |
else |
540 |
sv[i]->call (*sv[i]); |
541 |
|
542 |
sv.pending = false; |
543 |
} |
544 |
} |
545 |
#endif |
546 |
|
547 |
#if IOM_IO |
548 |
for (int i = iow.size (); i--; ) |
549 |
if (!iow[i]) |
550 |
iow.erase_unordered (i); |
551 |
else |
552 |
{ |
553 |
io_watcher &w = *iow[i]; |
554 |
short revents = w.events; |
555 |
|
556 |
if (!FD_ISSET (w.fd, &rfd)) revents &= ~EVENT_READ; |
557 |
if (!FD_ISSET (w.fd, &wfd)) revents &= ~EVENT_WRITE; |
558 |
|
559 |
if (revents) |
560 |
w.call (w, revents); |
561 |
} |
562 |
#endif |
563 |
} |
564 |
else if (fds < 0 && errno != EINTR) |
565 |
{ |
566 |
perror ("io_manager: fatal error while waiting for I/O or time event, aborting."); |
567 |
abort (); |
568 |
} |
569 |
#if IOM_IDLE |
570 |
else |
571 |
for (int i = iw.size (); i--; ) |
572 |
if (!iw[i]) |
573 |
iw.erase_unordered (i); |
574 |
else |
575 |
iw[i]->call (*iw[i]); |
576 |
#endif |
577 |
|
578 |
#else |
579 |
need_set_now = true; |
580 |
|
581 |
if (to) |
582 |
event_loop (EVLOOP_NONBLOCK); |
583 |
else |
584 |
event_loop (EVLOOP_ONCE); |
585 |
|
586 |
if (need_set_now) set_now (); |
587 |
#endif |
588 |
//TODO: IOM_IDLE |
589 |
} |
590 |
} |
591 |
|