Modified: trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm (246052 => 246053)
--- trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm 2019-06-04 00:25:40 UTC (rev 246052)
+++ trunk/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm 2019-06-04 01:28:36 UTC (rev 246053)
@@ -41,6 +41,7 @@
// the background task before the UIKit timeout (We get killed if we do not release the background task within 5 seconds
// on the expiration handler getting called).
static const Seconds releaseBackgroundTaskAfterExpirationDelay { 2_s };
+static const Seconds maximumBackgroundTaskDuration { 20_s };
@interface WKProcessAssertionBackgroundTaskManager : NSObject
@@ -56,7 +57,8 @@
UIBackgroundTaskIdentifier _backgroundTask;
HashSet<ProcessAndUIAssertion*> _assertionsNeedingBackgroundTask;
BOOL _applicationIsBackgrounded;
- dispatch_block_t _pendingTaskReleaseTask;
+ dispatch_block_t _releaseTask;
+ dispatch_block_t _timeoutTask;
}
+ (WKProcessAssertionBackgroundTaskManager *)shared
@@ -65,6 +67,11 @@
return shared;
}
+static bool isBackgroundState(BKSApplicationState state)
+{
+ return state == BKSApplicationStateBackgroundRunning || state == BKSApplicationStateBackgroundTaskSuspended;
+}
+
- (instancetype)init
{
self = [super init];
@@ -73,14 +80,30 @@
_backgroundTask = UIBackgroundTaskInvalid;
- [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationWillEnterForegroundNotification object:[UIApplication sharedApplication] queue:nil usingBlock:^(NSNotification *) {
+ {
+ auto applicationStateMonitor = adoptNS([[BKSApplicationStateMonitor alloc] init]);
+ _applicationIsBackgrounded = isBackgroundState([applicationStateMonitor mostElevatedApplicationStateForPID:getpid()]);
+ [applicationStateMonitor invalidate];
+ }
+
+ NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];
+ UIApplication *application = [UIApplication sharedApplication];
+
+ [notificationCenter addObserverForName:UIApplicationWillEnterForegroundNotification object:application queue:nil usingBlock:^(NSNotification *) {
+ RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager: Application will enter foreground", self);
_applicationIsBackgrounded = NO;
- [self _cancelPendingReleaseTask];
+ [self _cancelReleaseTask];
+ [self _cancelTimeoutTask];
[self _updateBackgroundTask];
}];
- [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationDidEnterBackgroundNotification object:[UIApplication sharedApplication] queue:nil usingBlock:^(NSNotification *) {
+ [notificationCenter addObserverForName:UIApplicationDidEnterBackgroundNotification object:application queue:nil usingBlock:^(NSNotification *) {
+ RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager: Application did enter background", self);
_applicationIsBackgrounded = YES;
+
+ // We do not want to keep the app awake for more than 20 seconds after it gets backgrounded, so start the timeout timer now.
+ if (_backgroundTask != UIBackgroundTaskInvalid)
+ [self _scheduleTimeoutTask];
}];
return self;
@@ -112,35 +135,83 @@
assertion->uiAssertionWillExpireImminently();
}
+- (void)_scheduleTimeoutTask
+{
+ ASSERT(_backgroundTask != UIBackgroundTaskInvalid);
+ if (_timeoutTask)
+ return;
+
+ RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _scheduleTimeoutTask", self);
+ _timeoutTask = dispatch_block_create((dispatch_block_flags_t)0, ^{
+ _timeoutTask = nil;
+ RELEASE_LOG_ERROR(ProcessSuspension, "Background task was running for too long so WebKit will end it shortly.");
+ [self _backgroundTaskExpired];
+ });
+
+ dispatch_after(dispatch_time(DISPATCH_TIME_NOW, maximumBackgroundTaskDuration.value() * NSEC_PER_SEC), dispatch_get_main_queue(), _timeoutTask);
+#if !__has_feature(objc_arc)
+ // dispatch_async() does a Block_copy() / Block_release() on behalf of the caller.
+ Block_release(_timeoutTask);
+#endif
+}
+
+- (void)_cancelTimeoutTask
+{
+ if (!_timeoutTask)
+ return;
+
+ RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _cancelTimeoutTask", self);
+ dispatch_block_cancel(_timeoutTask);
+ _timeoutTask = nil;
+}
+
- (void)_scheduleReleaseTask
{
- ASSERT(!_pendingTaskReleaseTask);
- if (_pendingTaskReleaseTask)
+ ASSERT(!_releaseTask);
+ if (_releaseTask)
return;
RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _scheduleReleaseTask because the expiration handler has been called", self);
- _pendingTaskReleaseTask = dispatch_block_create((dispatch_block_flags_t)0, ^{
- _pendingTaskReleaseTask = nil;
+ _releaseTask = dispatch_block_create((dispatch_block_flags_t)0, ^{
+ _releaseTask = nil;
[self _releaseBackgroundTask];
});
- dispatch_after(dispatch_time(DISPATCH_TIME_NOW, releaseBackgroundTaskAfterExpirationDelay.value() * NSEC_PER_SEC), dispatch_get_main_queue(), _pendingTaskReleaseTask);
+ dispatch_after(dispatch_time(DISPATCH_TIME_NOW, releaseBackgroundTaskAfterExpirationDelay.value() * NSEC_PER_SEC), dispatch_get_main_queue(), _releaseTask);
#if !__has_feature(objc_arc)
// dispatch_async() does a Block_copy() / Block_release() on behalf of the caller.
- Block_release(_pendingTaskReleaseTask);
+ Block_release(_releaseTask);
#endif
}
-- (void)_cancelPendingReleaseTask
+- (void)_cancelReleaseTask
{
- if (!_pendingTaskReleaseTask)
+ if (!_releaseTask)
return;
- RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _cancelPendingReleaseTask because the application is foreground again", self);
- dispatch_block_cancel(_pendingTaskReleaseTask);
- _pendingTaskReleaseTask = nil;
+ RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _cancelReleaseTask because the application is foreground again", self);
+ dispatch_block_cancel(_releaseTask);
+ _releaseTask = nil;
}
+- (void)_backgroundTaskExpired
+{
+ RELEASE_LOG_ERROR(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _backgroundTaskExpired", self);
+ [self _cancelTimeoutTask];
+
+ // Tell our child processes they will suspend imminently.
+ if (RunLoop::isMain())
+ [self _notifyAssertionsOfImminentSuspension];
+ else {
+ // The expiration handler gets called on a non-main thread when the underlying assertion could not be taken (rdar://problem/27278419).
+ dispatch_sync(dispatch_get_main_queue(), ^{
+ [self _notifyAssertionsOfImminentSuspension];
+ });
+ }
+
+ [self _scheduleReleaseTask];
+}
+
- (void)_updateBackgroundTask
{
if (!_assertionsNeedingBackgroundTask.isEmpty() && _backgroundTask == UIBackgroundTaskInvalid) {
@@ -150,17 +221,8 @@
}
RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - beginBackgroundTaskWithName", self);
_backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithName:@"com.apple.WebKit.ProcessAssertion" expirationHandler:^{
- RELEASE_LOG_ERROR(ProcessSuspension, "Background task expired while holding WebKit ProcessAssertion (isMainThread? %d).", RunLoop::isMain());
- // The expiration handler gets called on a non-main thread when the underlying assertion could not be taken (rdar://problem/27278419).
- if (RunLoop::isMain())
- [self _notifyAssertionsOfImminentSuspension];
- else {
- dispatch_sync(dispatch_get_main_queue(), ^{
- [self _notifyAssertionsOfImminentSuspension];
- });
- }
-
- [self _scheduleReleaseTask];
+ RELEASE_LOG_ERROR(ProcessSuspension, "Background task expired while holding WebKit ProcessAssertion (isMainThread? %d, _applicationIsBackgrounded? %d).", RunLoop::isMain(), _applicationIsBackgrounded);
+ [self _backgroundTaskExpired];
}];
} else if (_assertionsNeedingBackgroundTask.isEmpty())
[self _releaseBackgroundTask];
@@ -173,6 +235,8 @@
RELEASE_LOG(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - endBackgroundTask", self);
[[UIApplication sharedApplication] endBackgroundTask:_backgroundTask];
+ [self _cancelReleaseTask];
+ [self _cancelTimeoutTask];
_backgroundTask = UIBackgroundTaskInvalid;
}
