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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// Copyright (c) 1996-2000 Live Networks, Inc. All rights reserved.
// Basic Usage Environment: for a simple, non-scripted, console application
// Implementation
#ifndef IMN_PIM
#include "BasicUsageEnvironment.hh"
#include "HandlerSet.hh"
#include <stdio.h>
#if defined(_QNX4)
#include <sys/select.h>
#include <unix.h>
#endif
////////// BasicTaskScheduler //////////
BasicTaskScheduler* BasicTaskScheduler::createNew() {
return new BasicTaskScheduler();
}
BasicTaskScheduler::BasicTaskScheduler()
: fMaxNumSockets(0) {
FD_ZERO(&fReadSet);
}
BasicTaskScheduler::~BasicTaskScheduler() {
}
#ifndef MILLION
#define MILLION 1000000
#endif
void BasicTaskScheduler::SingleStep(unsigned maxDelayTime) {
fd_set readSet = fReadSet; // make a copy for this select() call
DelayInterval const& timeToDelay = fDelayQueue.timeToNextAlarm();
struct timeval tv_timeToDelay;
tv_timeToDelay.tv_sec = timeToDelay.seconds();
tv_timeToDelay.tv_usec = timeToDelay.useconds();
// Very large "tv_sec" values cause select() to fail.
// Don't make it any larger than 1 million seconds (11.5 days)
const long MAX_TV_SEC = MILLION;
if (tv_timeToDelay.tv_sec > MAX_TV_SEC) {
tv_timeToDelay.tv_sec = MAX_TV_SEC;
}
// Also check our "maxDelayTime" parameter (if it's > 0):
if (maxDelayTime > 0 &&
(tv_timeToDelay.tv_sec > (long)maxDelayTime/MILLION ||
(tv_timeToDelay.tv_sec == (long)maxDelayTime/MILLION &&
tv_timeToDelay.tv_usec > (long)maxDelayTime%MILLION))) {
tv_timeToDelay.tv_sec = maxDelayTime/MILLION;
tv_timeToDelay.tv_usec = maxDelayTime%MILLION;
}
int selectResult = select(fMaxNumSockets, &readSet, NULL, NULL,
&tv_timeToDelay);
if (selectResult < 0) {
#if defined(__WIN32__) || defined(_WIN32)
int err = WSAGetLastError();
// For some unknown reason, select() in Windoze sometimes fails with WSAEINVAL if
// it was called with no entries set in "readSet". If this happens, ignore it:
if (err == WSAEINVAL && readSet.fd_count == 0) {
err = 0;
// To stop this from happening again, create a dummy readable socket:
int dummySocketNum = socket(AF_INET, SOCK_DGRAM, 0);
FD_SET((unsigned)dummySocketNum, &fReadSet);
}
if (err != 0) {
#else
if (errno != EINTR && errno != EAGAIN) {
#endif
// Unexpected error - treat this as fatal:
#if !defined(_WIN32_WCE)
perror("BasicTaskScheduler::SingleStep(): select() fails");
#endif
exit(0);
}
}
// Handle any delayed event that may have come due:
fDelayQueue.handleAlarm();
// Call the handler function for one readable socket:
HandlerIterator iter(*fReadHandlers);
HandlerDescriptor* handler;
// To ensure forward progress through the handlers, begin past the last
// socket number that we handled:
if (fLastHandledSocketNum >= 0) {
while ((handler = iter.next()) != NULL) {
if (handler->socketNum == fLastHandledSocketNum) break;
}
if (handler == NULL) {
fLastHandledSocketNum = -1;
iter.reset(); // start from the beginning instead
}
}
while ((handler = iter.next()) != NULL) {
if (FD_ISSET(handler->socketNum, &readSet) &&
FD_ISSET(handler->socketNum, &fReadSet) /* sanity check */ &&
handler->handlerProc != NULL) {
fLastHandledSocketNum = handler->socketNum;
// Note: we set "fLastHandledSocketNum" before calling the handler,
// in case the handler calls "doEventLoop()" reentrantly.
(*handler->handlerProc)(handler->clientData, SOCKET_READABLE);
break;
}
}
if (handler == NULL && fLastHandledSocketNum >= 0) {
// We didn't call a handler, but we didn't get to check all of them,
// so try again from the beginning:
iter.reset();
while ((handler = iter.next()) != NULL) {
if (FD_ISSET(handler->socketNum, &readSet) &&
FD_ISSET(handler->socketNum, &fReadSet) /* sanity check */ &&
handler->handlerProc != NULL) {
fLastHandledSocketNum = handler->socketNum;
// Note: we set "fLastHandledSocketNum" before calling the handler,
// in case the handler calls "doEventLoop()" reentrantly.
(*handler->handlerProc)(handler->clientData, SOCKET_READABLE);
break;
}
}
if (handler == NULL) fLastHandledSocketNum = -1;//because we didn't call a handler
}
}
void BasicTaskScheduler::turnOnBackgroundReadHandling(int socketNum,
BackgroundHandlerProc* handlerProc,
void* clientData) {
if (socketNum < 0) return;
FD_SET((unsigned)socketNum, &fReadSet);
fReadHandlers->assignHandler(socketNum, handlerProc, clientData);
if (socketNum+1 > fMaxNumSockets) {
fMaxNumSockets = socketNum+1;
}
}
void BasicTaskScheduler::turnOffBackgroundReadHandling(int socketNum) {
if (socketNum < 0) return;
FD_CLR((unsigned)socketNum, &fReadSet);
fReadHandlers->removeHandler(socketNum);
if (socketNum+1 == fMaxNumSockets) {
--fMaxNumSockets;
}
}
#endif
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