Attachment 370951 Details for Bug 198380 – Patch

[patch] Patch

bug-198380-20190530102947.patch (text/plain), 3.34 KB, created by Chris Dumez on 2019-05-30 10:29:48 PDT

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Creator: Chris Dumez

Created: 2019-05-30 10:29:48 PDT

Size: 3.34 KB

patch

obsolete

>Subversion Revision: 245892
>diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
>index 9eb299bb2e40cc78cf028df7a14269553885b317..8f1a43113801556478d373f1dc10966afeee45b0 100644
>--- a/Source/WebKit/ChangeLog
>+++ b/Source/WebKit/ChangeLog
>@@ -1,3 +1,23 @@
>+2019-05-30  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]):
>+
> 2019-05-30  Truitt Savell  <tsavell@apple.com>
> 
>         Unreviewed, rolling out r245881.
>diff --git a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>index 2aca868bb8b5713159c91d2abe5feca9461cc72f..2b9ab03ad269f2535b7694ab469e16d842a7ebfc 100644
>--- a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>+++ b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>@@ -150,7 +150,17 @@ - (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);
>+            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;
>+            }
>             // 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];

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Attachments on bug 198380: 370951 | 371163 | 371284