Avoid unnecessary libevent timers in the MessagePump

starboard/shared/libevent/socket_waiter_internal.cc

@@ -122,10 +122,7 @@ void GetSocketPipe(SbSocket* client_socket, SbSocket* server_socket) {
 }  // namespace
 
 SbSocketWaiterPrivate::SbSocketWaiterPrivate()
-    : thread_(pthread_self()),
-      base_(event_base_new()),
-      waiting_(false),
-      woken_up_(false) {
+    : thread_(pthread_self()), base_(event_base_new()), woken_up_(false) {
 #if USE_POSIX_PIPE
   int fds[2];
   int result = pipe(fds);
@@ -274,33 +271,38 @@ void SbSocketWaiterPrivate::Wait() {
 SbSocketWaiterResult SbSocketWaiterPrivate::WaitTimed(int64_t duration_usec) {
   SB_DCHECK(pthread_equal(pthread_self(), thread_));
 
+  if ((duration_usec == 0) || (duration_usec == kSbInt64Max)) {
+    // There is no need for a timeout event in these cases.
+    event_base_loop(base_,
+                    (duration_usec == 0) ? EVLOOP_ONCE | EVLOOP_NONBLOCK : 0);
+
+    SbSocketWaiterResult result = woken_up_ ? kSbSocketWaiterResultWokenUp
+                                            : kSbSocketWaiterResultTimedOut;
+    woken_up_ = false;
+
+    return result;
+  }
+
   // The way to do this is apparently to create a timeout event, call WakeUp
   // inside that callback, and then just do a normal wait.
   struct event event;
   timeout_set(&event, &SbSocketWaiterPrivate::LibeventTimeoutCallback, this);
   event_base_set(base_, &event);
 
-  if (duration_usec < kSbInt64Max) {
-    struct timeval tv;
-    tv.tv_sec = duration_usec / 1'000'000;
-    tv.tv_usec = duration_usec % 1'000'000;
-    timeout_add(&event, &tv);
-  }
+  struct timeval tv;
+  tv.tv_sec = duration_usec / 1'000'000;
+  tv.tv_usec = duration_usec % 1'000'000;
+  timeout_add(&event, &tv);
 
-  waiting_ = true;
   event_base_loop(base_, 0);
-  waiting_ = false;
 
   SbSocketWaiterResult result =
       woken_up_ ? kSbSocketWaiterResultWokenUp : kSbSocketWaiterResultTimedOut;
   woken_up_ = false;
 
-  if (duration_usec < kSbInt64Max) {
-    // We clean this up, in case we were awakened early, to prevent a spurious
-    // wake-up later.
-    timeout_del(&event);
-  }
-
+  // We clean this up, in case we were awakened early, to prevent a spurious
+  // wake-up later.
+  timeout_del(&event);
   return result;
 }
 
@@ -362,7 +364,6 @@ void SbSocketWaiterPrivate::HandleSignal(Waitee* waitee,
 }
 
 void SbSocketWaiterPrivate::HandleWakeUpRead() {
-  SB_DCHECK(waiting_);
   // Remove and discard the wakeup byte.
   char buf;
   int bytes_read = HANDLE_EINTR(read(wakeup_read_fd_, &buf, 1));

starboard/shared/libevent/socket_waiter_internal.h

@@ -136,9 +136,6 @@ struct SbSocketWaiterPrivate {
   // The registry of currently registered Waitees.
   WaiteesMap waitees_;
 
-  // Whether or not the waiter is actually waiting.
-  bool waiting_;
-
   // Whether or not the waiter was woken up.
   bool woken_up_;
 

third_party/libevent/event.c

@@ -918,7 +918,7 @@ timeout_correct(struct event_base *base, struct timeval *tv)
 	pev = base->timeheap.p;
 	size = base->timeheap.n;
 	for (; size-- > 0; ++pev) {
-		struct evtimeval *ev_tv = &(**pev).ev_timeout;
+		struct timeval *ev_tv = &(**pev).ev_timeout;
 		evutil_timersub(ev_tv, &off, ev_tv);
 	}
 	/* Now remember what the new time turned out to be. */

third_party/libevent/event.h

@@ -204,20 +204,6 @@ typedef unsigned short u_short;
 #define EV_SIGNAL	0x08
 #define EV_PERSIST	0x10	/* Persistant event */
 
-#ifdef STARBOARD
-struct evtimeval {
-#if SB_IS(64_BIT)
-	int64_t	tv_sec;		/* seconds */
-	int64_t	tv_usec;	/* and microseconds */
-#else
-	int32_t	tv_sec;		/* seconds */
-	int32_t	tv_usec;	/* and microseconds */
-#endif
-};
-#else
-typedef struct timeval evtimeval;
-#endif
-
 /* Fix so that ppl dont have to run with <sys/queue.h> */
 #ifndef TAILQ_ENTRY
 #define _EVENT_DEFINED_TQENTRY
@@ -243,11 +229,7 @@ struct event {
 	short ev_ncalls;
 	short *ev_pncalls;	/* Allows deletes in callback */
 
-#if defined(STARBOARD)
-	struct evtimeval ev_timeout;
-#else
   struct timeval ev_timeout;
-#endif
 
 	int ev_pri;		/* smaller numbers are higher priority */