os: Compute timeout in milliseconds instead of struct timeval

The timeout resolution offered in the AdjustWaitForDelay call is
only milliseconds, so passing around the timeout as a pointer to a
struct timeval is not helpful. Doing everything in milliseconds up to
the point of the select call simplifies the code without affecting
functionality at all.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>

3 files changed, 23 insertions, 33 deletions

diff --git a/include/os.h b/include/os.h
index 5f651418b..9a3d9a9a0 100644
--- a/include/os.h
+++ b/include/os.h
@@ -182,8 +182,7 @@ extern void ForceClockId(clockid_t /* forced_clockid */);
 extern _X_EXPORT CARD32 GetTimeInMillis(void);
 extern _X_EXPORT CARD64 GetTimeInMicros(void);
 
-extern _X_EXPORT void AdjustWaitForDelay(void *waitTime,
-                                         unsigned long newdelay);
+extern _X_EXPORT void AdjustWaitForDelay(void *waitTime, int newdelay);
 
 typedef struct _OsTimerRec *OsTimerPtr;
 
diff --git a/os/WaitFor.c b/os/WaitFor.c
index b6801fea9..7bdd39987 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -147,7 +147,7 @@ WaitForSomething(int *pClientsReady)
 {
     int i;
     struct timeval waittime, *wt;
-    INT32 timeout = 0;
+    int timeout;
     fd_set clientsReadable;
     fd_set clientsWritable;
     int curclient;
@@ -175,17 +175,15 @@ WaitForSomething(int *pClientsReady)
         if (workQueue)
             ProcessWorkQueue();
         if (XFD_ANYSET(&ClientsWithInput)) {
+            timeout = 0;
             someReady = TRUE;
-            waittime.tv_sec = 0;
-            waittime.tv_usec = 0;
-            wt = &waittime;
         }
         if (someReady) {
             XFD_COPYSET(&AllSockets, &LastSelectMask);
             XFD_UNSET(&LastSelectMask, &ClientsWithInput);
         }
         else {
-            wt = NULL;
+            timeout = -1;
             if (timers) {
                 now = GetTimeInMillis();
                 timeout = timers->expires - now;
@@ -198,16 +196,20 @@ WaitForSomething(int *pClientsReady)
                     timeout = timers->expires - now;
                     if (timeout < 0)
                         timeout = 0;
-                    waittime.tv_sec = timeout / MILLI_PER_SECOND;
-                    waittime.tv_usec = (timeout % MILLI_PER_SECOND) *
-                        (1000000 / MILLI_PER_SECOND);
-                    wt = &waittime;
                 }
             }
             XFD_COPYSET(&AllSockets, &LastSelectMask);
         }
 
-        BlockHandler(&wt);
+        BlockHandler(&timeout);
+        if (timeout < 0)
+            wt = NULL;
+        else {
+            waittime.tv_sec = timeout / MILLI_PER_SECOND;
+            waittime.tv_usec = (timeout % MILLI_PER_SECOND) *
+                (1000000 / MILLI_PER_SECOND);
+            wt = &waittime;
+        }
         if (NewOutputPending)
             FlushAllOutput();
         /* keep this check close to select() call to minimize race */
@@ -359,6 +361,16 @@ WaitForSomething(int *pClientsReady)
     return nready;
 }
 
+void
+AdjustWaitForDelay(void *waitTime, int newdelay)
+{
+    int *timeoutp = waitTime;
+    int timeout = *timeoutp;
+
+    if (timeout < 0 || newdelay < timeout)
+        *timeoutp = newdelay;
+}
+
 /* If time has rewound, re-run every affected timer.
  * Timers might drop out of the list, so we have to restart every time. */
 static void
diff --git a/os/utils.c b/os/utils.c
index a58603dfe..868a2d6de 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -513,27 +513,6 @@ GetTimeInMicros(void)
 #endif
 
 void
-AdjustWaitForDelay(void *waitTime, unsigned long newdelay)
-{
-    static struct timeval delay_val;
-    struct timeval **wt = (struct timeval **) waitTime;
-    unsigned long olddelay;
-
-    if (*wt == NULL) {
-        delay_val.tv_sec = newdelay / 1000;
-        delay_val.tv_usec = 1000 * (newdelay % 1000);
-        *wt = &delay_val;
-    }
-    else {
-        olddelay = (*wt)->tv_sec * 1000 + (*wt)->tv_usec / 1000;
-        if (newdelay < olddelay) {
-            (*wt)->tv_sec = newdelay / 1000;
-            (*wt)->tv_usec = 1000 * (newdelay % 1000);
-        }
-    }
-}
-
-void
 UseMsg(void)
 {
     ErrorF("use: X [:<display>] [option]\n");