diff options
-rw-r--r-- | src/socketengines/socketengine_select.cpp | 65 |
1 files changed, 28 insertions, 37 deletions
diff --git a/src/socketengines/socketengine_select.cpp b/src/socketengines/socketengine_select.cpp index 3f5210f3c..5c61ff0ae 100644 --- a/src/socketengines/socketengine_select.cpp +++ b/src/socketengines/socketengine_select.cpp @@ -92,84 +92,75 @@ int SelectEngine::GetRemainingFds() int SelectEngine::DispatchEvents() { - int result = 0; timeval tval; int sresult = 0; socklen_t codesize; - int errcode; + int errcode = 0; FD_ZERO(&wfdset); FD_ZERO(&rfdset); FD_ZERO(&errfdset); + /* Populate the select FD set (this is why select sucks compared to epoll, kqueue, IOCP) */ for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++) { if (ref[a->second]->Readable()) + /* Read notifications */ FD_SET (a->second, &rfdset); else + /* Write notifications */ FD_SET (a->second, &wfdset); + + /* Explicitly one-time writeable */ if (writeable[a->second]) FD_SET (a->second, &wfdset); + /* All sockets must receive error notifications regardless */ FD_SET (a->second, &errfdset); } + /* One second waits */ tval.tv_sec = 1; tval.tv_usec = 0; sresult = select(FD_SETSIZE, &rfdset, &wfdset, &errfdset, &tval); - if (sresult > 0) - { - for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++) - { - if ((FD_ISSET (a->second, &rfdset)) || (FD_ISSET (a->second, &wfdset)) || FD_ISSET (a->second, &errfdset)) - { - ev[result++] = ref[a->second]; - } - } - } + /* Nothing to process this time around */ + if (sresult < 1) + return 0; - /** An event handler may remove its own descriptor from the list, therefore it is not - * safe to directly iterate over the list and dispatch events there with STL iterators. - * Thats a shame because it makes this code slower and more resource intensive, but maybe - * the user should stop using select(), as select() smells anyway. - */ - for (int i = 0; i < result; i++) + /* Safe assumption (as of 1.1 anyway) that a socket can't remove itself from the list in the middle of the loop */ + for (std::map<int,int>::iterator a = fds.begin(); a != fds.end(); a++) { - if (ev[i]) + EventHandler* ev = ref[a->second]; + if (ev) { - if (FD_ISSET (ev[i]->GetFd(), &errfdset)) + if (FD_ISSET (ev->GetFd(), &errfdset)) { ErrorEvents++; - - if (getsockopt(ev[i]->GetFd(), SOL_SOCKET, SO_ERROR, (char*)&errcode, &codesize) < 0) + if (getsockopt(ev->GetFd(), SOL_SOCKET, SO_ERROR, (char*)&errcode, &codesize) < 0) errcode = errno; - ev[i]->HandleEvent(EVENT_ERROR, errcode); - + ev->HandleEvent(EVENT_ERROR, errcode); continue; } else { - if (writeable[ev[i]->GetFd()]) + /* NOTE: This is a pair of seperate if statements as the socket + * may be in both read and writeable state at the same time. + * If an error event occurs above it is not worth processing the + * read and write states even if set. + */ + if (FD_ISSET (ev->GetFd(), &wfdset)) { WriteEvents++; - writeable[ev[i]->GetFd()] = false; - ev[i]->HandleEvent(EVENT_WRITE); + writeable[ev->GetFd()] = false; + ev->HandleEvent(EVENT_WRITE); } - else + if (FD_ISSET (ev->GetFd(), &rfdset)) { - if (ev[i]->Readable()) - { ReadEvents++; - ev[i]->HandleEvent(EVENT_READ); - } - else - { - WriteEvents++; - ev[i]->HandleEvent(EVENT_WRITE); - } + ev->HandleEvent(EVENT_READ); } } } |