Attachment 371284 Details for Bug 198380 – Patch

[patch] Patch

bug-198380-20190604083047.patch (text/plain), 3.41 KB, created by Chris Dumez on 2019-06-04 08:30:48 PDT

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Creator: Chris Dumez

Created: 2019-06-04 08:30:48 PDT

Size: 3.41 KB

patch

obsolete

>Subversion Revision: 246053
>diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
>index ce82571b79aec000b4b25f3f8468b2f98d3a12b6..76d15cc4291b5ca49c3316c4fe0b9fced21d174f 100644
>--- a/Source/WebKit/ChangeLog
>+++ b/Source/WebKit/ChangeLog
>@@ -1,3 +1,23 @@
>+2019-06-04  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 Geoff Garen.
>+
>+        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]):
>+
> 2019-06-03  Chris Dumez  <cdumez@apple.com>
> 
>         [iOS] Do not prevent app suspension for more than 20 seconds after getting backgrounded
>diff --git a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>index f852b22ac878eb02f93a01895f1788efc2bf093f..f5d2f6446d09f360c4128483ebbe4339e42e302e 100644
>--- a/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>+++ b/Source/WebKit/UIProcess/ios/ProcessAssertionIOS.mm
>@@ -197,6 +197,7 @@ - (void)_cancelReleaseTask
> - (void)_backgroundTaskExpired
> {
>     RELEASE_LOG_ERROR(ProcessSuspension, "%p - WKProcessAssertionBackgroundTaskManager - _backgroundTaskExpired", self);
>+    ASSERT(_applicationIsBackgrounded);
>     [self _cancelTimeoutTask];
> 
>     // Tell our child processes they will suspend imminently.
>@@ -222,6 +223,17 @@ - (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, _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 _releaseBackgroundTask];
>+                dispatch_async(dispatch_get_main_queue(), ^{
>+                    [self _updateBackgroundTask];
>+                });
>+                return;
>+            }
>+            
>             [self _backgroundTaskExpired];
>         }];
>     } else if (_assertionsNeedingBackgroundTask.isEmpty())

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Attachments on bug 198380: 370951 | 371163 | 371284