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-rw-r--r--src/socketengines/socketengine_select.cpp65
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);
}
}
}