Cherry pick PR #3027: [Android] Fix CPU spinning of StarboardMain. (#…

…3045)

Refer to the original PR: #3027

An integer overflow in a downconversion resulted in a negative timeout
being used for the ALooper_pollAll call.

This fixes that, and adds a ALooper_wake when a non-system event is
injectet.

Change `handle_system_events_` from `bool` to `atomic_bool` to make it
thread safe. Replace deprecated `ALooper_pollAll` with the suggested
`ALooper_pollOnce` (*1) to avoid swallowing of `ALooper_wake` calls.

Left the `kMaxPollingTimeMillisecond` workaround for swallowed wake
calls in place, but increased the timeout to one second to minimize CPU
usage.

*1:
https://developer.android.com/ndk/reference/group/looper#group___looper_1gab2585652f8ae2e2444979194ebe32aaf

b/335901937

Co-authored-by: Jelle Foks <[email protected]>

starboard/android/shared/application_android.cc

@@ -101,6 +101,7 @@ ApplicationAndroid::ApplicationAndroid(ALooper* looper)
       QueueApplication(sb_event_handle_callback),
 #endif  // SB_API_VERSION >= 15
       last_is_accessibility_high_contrast_text_enabled_(false) {
+  handle_system_events_.store(true);
   // Initialize Time Zone early so that local time works correctly.
   // Called once here to help SbTimeZoneGet*Name()
   tzset();
@@ -209,19 +210,23 @@ bool ApplicationAndroid::DestroyWindow(SbWindow window) {
 
 Event* ApplicationAndroid::WaitForSystemEventWithTimeout(int64_t time) {
   // Limit the polling time in case some non-system event is injected.
-  const int kMaxPollingTimeMillisecond = 10;
+  const int kMaxPollingTimeMillisecond = 1000;
 
   // Convert from microseconds to milliseconds, taking the ceiling value.
   // If we take the floor, or round, then we end up busy looping every time
   // the next event time is less than one millisecond.
-  int timeout_millis = (time + 1000 - 1) / 1000;
+  int timeout_millis =
+      (time <
+       std::min(kSbInt64Max - 1000, 1000 * static_cast<int64_t>(INT_MAX - 1)))
+          ? (time + 1000 - 1) / 1000
+          : INT_MAX;
   int looper_events;
-  int ident = ALooper_pollAll(
+  int ident = ALooper_pollOnce(
       std::min(std::max(timeout_millis, 0), kMaxPollingTimeMillisecond), NULL,
       &looper_events, NULL);
 
   // Ignore new system events while processing one.
-  handle_system_events_ = false;
+  handle_system_events_.store(false);
 
   switch (ident) {
     case kLooperIdAndroidCommand:
@@ -232,7 +237,7 @@ Event* ApplicationAndroid::WaitForSystemEventWithTimeout(int64_t time) {
       break;
   }
 
-  handle_system_events_ = true;
+  handle_system_events_.store(true);
 
   // Always return NULL since we already dispatched our own system events.
   return NULL;

starboard/android/shared/application_android.h

@@ -120,7 +120,7 @@ class ApplicationAndroid
   void OnSuspend() override;
 
   // --- QueueApplication overrides ---
-  bool MayHaveSystemEvents() override { return handle_system_events_; }
+  bool MayHaveSystemEvents() override { return handle_system_events_.load(); }
   Event* WaitForSystemEventWithTimeout(int64_t time) override;
   void WakeSystemEventWait() override;
 
@@ -136,7 +136,7 @@ class ApplicationAndroid
 
   // In certain situations, the Starboard thread should not try to process new
   // system events (e.g. while one is being processed).
-  bool handle_system_events_ = true;
+  atomic_bool handle_system_events_;
 
   // Synchronization for commands that change availability of Android resources
   // such as the input and/or native_window_.