Fix for bug 129364. Eliminate a window of time in which notifiers could fire when we hadn't set up the polling thread on the poll descriptors, which could cause lost notifications and FTP stalls. Also revert to PR_FAST_INTSON() from PR_INTSON(), which seems to fix a permanent stall issue on Mac OS X. r=wtc

nsprpub/pr/src/md/mac/macsockotpt.c

@@ -1931,8 +1931,6 @@ PRInt32 _MD_poll(PRPollDesc *pds, PRIntn npds, PRIntervalTime timeout)
     
     PRThread    *thread = _PR_MD_CURRENT_THREAD();
     PRInt32     ready;
-    intn        is;
-    PRBool      needsToWait = PR_FALSE;
     
     if (npds > DESCRIPTOR_FLAGS_ARRAY_SIZE)
     {
@@ -1948,40 +1946,45 @@ PRInt32 _MD_poll(PRPollDesc *pds, PRIntn npds, PRIntervalTime timeout)
         readFlags = ioFlags;
         writeFlags = &ioFlags[npds];
     }
-    
-    (void)CheckPollDescMethods(pds, npds, readFlags, writeFlags);
 
-    _PR_INTSOFF(is);
-    PR_Lock(thread->md.asyncIOLock);
-    
-    (void)CheckPollDescEndpoints(pds, npds, readFlags, writeFlags);
-    ready = CountReadyPollDescs(pds, npds);
-    
-    if ((ready == 0) && (timeout != PR_INTERVAL_NO_WAIT))
-    {
-        PrepareForAsyncCompletion(thread, 0);
-        SetDescPollThread(pds, npds, thread);
-        needsToWait = PR_TRUE;
-    }    
+    if (timeout != PR_INTERVAL_NO_WAIT) {
+        intn        is;
         
-    PR_Unlock(thread->md.asyncIOLock);
-    _PR_INTSON(is);
-
-    if (needsToWait)
-    {
-        WaitOnThisThread(thread, timeout);
-
-        // since we may have been woken by a pollable event
-        // firing, we have to check both poll methods and
-        // endpoints.
+        // we have to be outside the lock when calling this, since
+        // it can call arbitrary user code (including other socket
+        // entry points)
         (void)CheckPollDescMethods(pds, npds, readFlags, writeFlags);
+
+        _PR_INTSOFF(is);
+        PR_Lock(thread->md.asyncIOLock);
+        PrepareForAsyncCompletion(thread, 0);
+
+        SetDescPollThread(pds, npds, thread);
+
         (void)CheckPollDescEndpoints(pds, npds, readFlags, writeFlags);
+
+        PR_Unlock(thread->md.asyncIOLock);
+        _PR_FAST_INTSON(is);
+
         ready = CountReadyPollDescs(pds, npds);
 
+        if (ready == 0) {
+            WaitOnThisThread(thread, timeout);
+
+            // since we may have been woken by a pollable event firing,
+            // we have to check both poll methods and endpoints.
+            (void)CheckPollDescMethods(pds, npds, readFlags, writeFlags);
+            (void)CheckPollDescEndpoints(pds, npds, readFlags, writeFlags);
+            ready = CountReadyPollDescs(pds, npds);
+        }
+        
+        thread->io_pending = PR_FALSE;
         SetDescPollThread(pds, npds, NULL);
     }
     else {
-        thread->io_pending = PR_FALSE;
+        (void)CheckPollDescMethods(pds, npds, readFlags, writeFlags);
+        (void)CheckPollDescEndpoints(pds, npds, readFlags, writeFlags);
+        ready = CountReadyPollDescs(pds, npds);    
     }
 
     if (readFlags != readFlagsArray)