/********** 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 3 of the License, or (at your option) any later version. (See .) 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA **********/ // Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved. // Basic Usage Environment: for a simple, non-scripted, console application // Implementation #include "BasicUsageEnvironment.hh" #include "HandlerSet.hh" #include #if defined(_QNX4) #include #include #endif ////////// BasicTaskScheduler ////////// BasicTaskScheduler* BasicTaskScheduler::createNew(unsigned maxSchedulerGranularity) { return new BasicTaskScheduler(maxSchedulerGranularity); } BasicTaskScheduler::BasicTaskScheduler(unsigned maxSchedulerGranularity) : fMaxSchedulerGranularity(maxSchedulerGranularity), fMaxNumSockets(0) #if defined(__WIN32__) || defined(_WIN32) , fDummySocketNum(-1) #endif { FD_ZERO(&fReadSet); FD_ZERO(&fWriteSet); FD_ZERO(&fExceptionSet); if (maxSchedulerGranularity > 0) schedulerTickTask(); // ensures that we handle events frequently } BasicTaskScheduler::~BasicTaskScheduler() { #if defined(__WIN32__) || defined(_WIN32) if (fDummySocketNum >= 0) closeSocket(fDummySocketNum); #endif } void BasicTaskScheduler::schedulerTickTask(void* clientData) { ((BasicTaskScheduler*)clientData)->schedulerTickTask(); } void BasicTaskScheduler::schedulerTickTask() { scheduleDelayedTask(fMaxSchedulerGranularity, schedulerTickTask, this); } #ifndef MILLION #define MILLION 1000000 #endif void BasicTaskScheduler::SingleStep(unsigned maxDelayTime) { fd_set readSet = fReadSet; // make a copy for this select() call fd_set writeSet = fWriteSet; // ditto fd_set exceptionSet = fExceptionSet; // ditto 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, &writeSet, &exceptionSet, &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 = EINTR; // To stop this from happening again, create a dummy socket: if (fDummySocketNum >= 0) closeSocket(fDummySocketNum); fDummySocketNum = socket(AF_INET, SOCK_DGRAM, 0); FD_SET((unsigned)fDummySocketNum, &fReadSet); } if (err != EINTR) { #else if (errno != EINTR && errno != EAGAIN) { #endif // Unexpected error - treat this as fatal: #if !defined(_WIN32_WCE) perror("BasicTaskScheduler::SingleStep(): select() fails"); // Because this failure is often "Bad file descriptor" - which is caused by an invalid socket number (i.e., a socket number // that had already been closed) being used in "select()" - we print out the sockets that were being used in "select()", // to assist in debugging: fprintf(stderr, "socket numbers used in the select() call:"); for (int i = 0; i < 10000; ++i) { if (FD_ISSET(i, &fReadSet) || FD_ISSET(i, &fWriteSet) || FD_ISSET(i, &fExceptionSet)) { fprintf(stderr, " %d(", i); if (FD_ISSET(i, &fReadSet)) fprintf(stderr, "r"); if (FD_ISSET(i, &fWriteSet)) fprintf(stderr, "w"); if (FD_ISSET(i, &fExceptionSet)) fprintf(stderr, "e"); fprintf(stderr, ")"); } } fprintf(stderr, "\n"); #endif internalError(); } } // Call the handler function for one readable socket: HandlerIterator iter(*fHandlers); 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) { int sock = handler->socketNum; // alias int resultConditionSet = 0; if (FD_ISSET(sock, &readSet) && FD_ISSET(sock, &fReadSet)/*sanity check*/) resultConditionSet |= SOCKET_READABLE; if (FD_ISSET(sock, &writeSet) && FD_ISSET(sock, &fWriteSet)/*sanity check*/) resultConditionSet |= SOCKET_WRITABLE; if (FD_ISSET(sock, &exceptionSet) && FD_ISSET(sock, &fExceptionSet)/*sanity check*/) resultConditionSet |= SOCKET_EXCEPTION; if ((resultConditionSet&handler->conditionSet) != 0 && handler->handlerProc != NULL) { fLastHandledSocketNum = sock; // Note: we set "fLastHandledSocketNum" before calling the handler, // in case the handler calls "doEventLoop()" reentrantly. (*handler->handlerProc)(handler->clientData, resultConditionSet); 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) { int sock = handler->socketNum; // alias int resultConditionSet = 0; if (FD_ISSET(sock, &readSet) && FD_ISSET(sock, &fReadSet)/*sanity check*/) resultConditionSet |= SOCKET_READABLE; if (FD_ISSET(sock, &writeSet) && FD_ISSET(sock, &fWriteSet)/*sanity check*/) resultConditionSet |= SOCKET_WRITABLE; if (FD_ISSET(sock, &exceptionSet) && FD_ISSET(sock, &fExceptionSet)/*sanity check*/) resultConditionSet |= SOCKET_EXCEPTION; if ((resultConditionSet&handler->conditionSet) != 0 && handler->handlerProc != NULL) { fLastHandledSocketNum = sock; // Note: we set "fLastHandledSocketNum" before calling the handler, // in case the handler calls "doEventLoop()" reentrantly. (*handler->handlerProc)(handler->clientData, resultConditionSet); break; } } if (handler == NULL) fLastHandledSocketNum = -1;//because we didn't call a handler } // Also handle any newly-triggered event (Note that we do this *after* calling a socket handler, // in case the triggered event handler modifies The set of readable sockets.) if (fTriggersAwaitingHandling != 0) { if (fTriggersAwaitingHandling == fLastUsedTriggerMask) { // Common-case optimization for a single event trigger: fTriggersAwaitingHandling &=~ fLastUsedTriggerMask; if (fTriggeredEventHandlers[fLastUsedTriggerNum] != NULL) { (*fTriggeredEventHandlers[fLastUsedTriggerNum])(fTriggeredEventClientDatas[fLastUsedTriggerNum]); } } else { // Look for an event trigger that needs handling (making sure that we make forward progress through all possible triggers): unsigned i = fLastUsedTriggerNum; EventTriggerId mask = fLastUsedTriggerMask; do { i = (i+1)%MAX_NUM_EVENT_TRIGGERS; mask >>= 1; if (mask == 0) mask = 0x80000000; if ((fTriggersAwaitingHandling&mask) != 0) { fTriggersAwaitingHandling &=~ mask; if (fTriggeredEventHandlers[i] != NULL) { (*fTriggeredEventHandlers[i])(fTriggeredEventClientDatas[i]); } fLastUsedTriggerMask = mask; fLastUsedTriggerNum = i; break; } } while (i != fLastUsedTriggerNum); } } // Also handle any delayed event that may have come due. fDelayQueue.handleAlarm(); } void BasicTaskScheduler ::setBackgroundHandling(int socketNum, int conditionSet, BackgroundHandlerProc* handlerProc, void* clientData) { if (socketNum < 0) return; #if !defined(__WIN32__) && !defined(_WIN32) && defined(FD_SETSIZE) if (socketNum >= (int)(FD_SETSIZE)) return; #endif FD_CLR((unsigned)socketNum, &fReadSet); FD_CLR((unsigned)socketNum, &fWriteSet); FD_CLR((unsigned)socketNum, &fExceptionSet); if (conditionSet == 0) { fHandlers->clearHandler(socketNum); if (socketNum+1 == fMaxNumSockets) { --fMaxNumSockets; } } else { fHandlers->assignHandler(socketNum, conditionSet, handlerProc, clientData); if (socketNum+1 > fMaxNumSockets) { fMaxNumSockets = socketNum+1; } if (conditionSet&SOCKET_READABLE) FD_SET((unsigned)socketNum, &fReadSet); if (conditionSet&SOCKET_WRITABLE) FD_SET((unsigned)socketNum, &fWriteSet); if (conditionSet&SOCKET_EXCEPTION) FD_SET((unsigned)socketNum, &fExceptionSet); } } void BasicTaskScheduler::moveSocketHandling(int oldSocketNum, int newSocketNum) { if (oldSocketNum < 0 || newSocketNum < 0) return; // sanity check #if !defined(__WIN32__) && !defined(_WIN32) && defined(FD_SETSIZE) if (oldSocketNum >= (int)(FD_SETSIZE) || newSocketNum >= (int)(FD_SETSIZE)) return; // sanity check #endif if (FD_ISSET(oldSocketNum, &fReadSet)) {FD_CLR((unsigned)oldSocketNum, &fReadSet); FD_SET((unsigned)newSocketNum, &fReadSet);} if (FD_ISSET(oldSocketNum, &fWriteSet)) {FD_CLR((unsigned)oldSocketNum, &fWriteSet); FD_SET((unsigned)newSocketNum, &fWriteSet);} if (FD_ISSET(oldSocketNum, &fExceptionSet)) {FD_CLR((unsigned)oldSocketNum, &fExceptionSet); FD_SET((unsigned)newSocketNum, &fExceptionSet);} fHandlers->moveHandler(oldSocketNum, newSocketNum); if (oldSocketNum+1 == fMaxNumSockets) { --fMaxNumSockets; } if (newSocketNum+1 > fMaxNumSockets) { fMaxNumSockets = newSocketNum+1; } }