hw/xwin: Introduce winProcessXEventsTimeout() to the concept of fractions of a second

Oh this is terrible.

Currently we only compute the select timeout in whole seconds.  This means if we
have less than 1 second remaining, we select with a timeout of 0 (i.e. poll)
which causes the task to spin, burning 100% CPU for the remaining timeout (and
possibly preventing the process we are waiting for from running :S)

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Colin Harrison <colin.harrison@virgin.net>

1 files changed, 22 insertions, 7 deletions

diff --git a/hw/xwin/winclipboardwndproc.c b/hw/xwin/winclipboardwndproc.c
index cbe6599f4..e19f678a7 100644
--- a/hw/xwin/winclipboardwndproc.c
+++ b/hw/xwin/winclipboardwndproc.c
@@ -74,10 +74,10 @@ winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
     int iConnNumber;
     struct timeval tv;
     int iReturn;
-    DWORD dwStopTime = (GetTickCount() / 1000) + iTimeoutSec;
+    DWORD dwStopTime = GetTickCount() + iTimeoutSec * 1000;
 
-    /* We need to ensure that all pending events are processed */
-    XSync(pDisplay, FALSE);
+    winDebug("winProcessXEventsTimeout () - pumping X events for %d seconds\n",
+             iTimeoutSec);
 
     /* Get our connection number */
     iConnNumber = ConnectionNumber(pDisplay);
@@ -85,17 +85,24 @@ winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
     /* Loop for X events */
     while (1) {
         fd_set fdsRead;
+        long remainingTime;
+
+        /* We need to ensure that all pending events are processed */
+        XSync(pDisplay, FALSE);
 
         /* Setup the file descriptor set */
         FD_ZERO(&fdsRead);
         FD_SET(iConnNumber, &fdsRead);
 
         /* Adjust timeout */
-        tv.tv_sec = dwStopTime - (GetTickCount() / 1000);
-        tv.tv_usec = 0;
+        remainingTime = dwStopTime - GetTickCount();
+        tv.tv_sec = remainingTime / 1000;
+        tv.tv_usec = (remainingTime % 1000) * 1000;
+        winDebug("winProcessXEventsTimeout () - %d milliseconds left\n",
+                 remainingTime);
 
         /* Break out if no time left */
-        if (tv.tv_sec < 0)
+        if (remainingTime <= 0)
             return WIN_XEVENTS_SUCCESS;
 
         /* Wait for an X event */
@@ -103,7 +110,7 @@ winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
                          &fdsRead,      /* Read mask */
                          NULL,  /* No write mask */
                          NULL,  /* No exception mask */
-                         &tv);  /* No timeout */
+                         &tv);  /* Timeout */
         if (iReturn < 0) {
             ErrorF("winProcessXEventsTimeout - Call to select () failed: %d.  "
                    "Bailing.\n", iReturn);
@@ -116,11 +123,19 @@ winProcessXEventsTimeout(HWND hwnd, int iWindow, Display * pDisplay,
             /* Exit when we see that server is shutting down */
             iReturn = winClipboardFlushXEvents(hwnd,
                                                iWindow, pDisplay, fUseUnicode);
+
+            winDebug
+                ("winProcessXEventsTimeout () - winClipboardFlushXEvents returned %d\n",
+                 iReturn);
+
             if (WIN_XEVENTS_NOTIFY == iReturn) {
                 /* Bail out if notify processed */
                 return iReturn;
             }
         }
+        else {
+            winDebug("winProcessXEventsTimeout - Spurious wake\n");
+        }
     }
 
     return WIN_XEVENTS_SUCCESS;