Attachment 371163 Details for Bug 198380 – Patch

[patch] Patch

bug-198380-20190602145540.patch (text/plain), 4.44 KB, created by Chris Dumez on 2019-06-02 14:55:42 PDT

(hide)

Description:

Filename:

MIME Type:

Creator: Chris Dumez

Created: 2019-06-02 14:55:42 PDT

Size: 4.44 KB

patch

obsolete

>Subversion Revision: 246023
>diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
>index 0ae2a31e86e4d05aafbe15edb3e6a522e0ed3b6c..bddb63d9468f03572a179ddc4ca7a2118c789397 100644
>--- a/Source/WebKit/ChangeLog
>+++ b/Source/WebKit/ChangeLog
>@@ -1,3 +1,23 @@
>+2019-06-02  Chris Dumez  <cdumez@apple.com>
>+
>+        [iOS] UIProcess' background task expiration handler may get called after the app is foreground again
>+        https://bugs.webkit.org/show_bug.cgi?id=198380
>+        <rdar://problem/49762471>
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        UIProcess' background task expiration handler may get called after the app is foreground again. When
>+        this happens, we already have a foreground assertion on behalf of the WebContent process, and the view
>+        is visible. We would send the WillSuspendImminently IPC to the WebContent process, which would freeze
>+        its layers, even though it is visible on screen.
>+
>+        To address the issue, we now check if the app is visible in the expiration handler. If it is visible,
>+        we do not notify clients of imminent suspension. Instead, we end the background task right away and
>+        call _updateBackgroundTask asynchronously to start a new background task if necessary.
>+
>+        * UIProcess/ios/ProcessAssertionIOS.mm:
>+        (-[WKProcessAssertionBackgroundTaskManager _updateBackgroundTask]):
>+
> 2019-06-01  Dean Jackson  <dino@apple.com>
> 
>         Provide an action to save an image on a link sheet
>diff --git a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>index 2aca868bb8b5713159c91d2abe5feca9461cc72f..9b05709278cb9a510c6bfa9bcf01366444282031 100644
>--- a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>+++ b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>@@ -65,6 +65,11 @@ + (WKProcessAssertionBackgroundTaskManager *)shared
>     return shared;
> }
> 
>+static bool isBackgroundState(BKSApplicationState state)
>+{
>+    return state == BKSApplicationStateBackgroundRunning || state == BKSApplicationStateBackgroundTaskSuspended;
>+}
>+
> - (instancetype)init
> {
>     self = [super init];
>@@ -73,6 +78,9 @@ - (instancetype)init
> 
>     _backgroundTask = UIBackgroundTaskInvalid;
> 
>+    auto applicationStateMonitor = adoptNS([[BKSApplicationStateMonitor alloc] init]);
>+    _applicationIsBackgrounded = isBackgroundState([applicationStateMonitor mostElevatedApplicationStateForPID:getpid()]);
>+
>     [[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationWillEnterForegroundNotification object:[UIApplication sharedApplication] queue:nil usingBlock:^(NSNotification *) {
>         _applicationIsBackgrounded = NO;
>         [self _cancelPendingReleaseTask];
>@@ -150,7 +158,23 @@ - (void)_updateBackgroundTask
>         }
>         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());
>+            RELEASE_LOG_ERROR(ProcessSuspension, "Background task expired while holding WebKit ProcessAssertion (isMainThread? %d, applicationIsBackgrounded? %d).", RunLoop::isMain(), _applicationIsBackgrounded);
>+
>+            // FIXME: Background tasks can currently expire while the application is in the foreground with UIKit for macOS.
>+            // See <rdar://problem/51313780>.
>+#if !PLATFORM(IOSMAC)
>+            if (!_applicationIsBackgrounded) {
>+                // We've received the invalidation warning after the app has become foreground again. In this case, we should not warn clients of imminent suspension.
>+                // To be safe (avoid potential killing), we end the task right away and call _updateBackgroundTask asynchronously to start a new task if necessary.
>+                [self _cancelPendingReleaseTask];
>+                [self _releaseBackgroundTask];
>+                dispatch_async(dispatch_get_main_queue(), ^{
>+                    [self _updateBackgroundTask];
>+                });
>+                return;
>+            }
>+#endif
>+
>             // 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];

Actions: View | Formatted Diff | Diff

Attachments on bug 198380: 370951 | 371163 | 371284