Changeset 269279 in webkit

Timestamp:

Nov 2, 2020, 4:40:51 PM (5 years ago)

Author:

Devin Rousso

Message:

guard UIScribbleInteraction class property observing behind a LOA check
​https://bugs.webkit.org/show_bug.cgi?id=218463
<rdar://problem/70747966>

Reviewed by Tim Horton.

Some apps appear to swizzle -[NSObject addObserver:forKeyPath:options:context:] without
support for the fact that the object can be a class rather than an instance and therefore
crash. Use a LOA check to guard observing +[UIScribbleInteraction isPencilInputExpected]
so that this doesn't happen, but only until the apps update, at which point they can fix it.

Source/WebCore:

• platform/cocoa/VersionChecks.h:

This appears to be the first instance of observing a class property, so add a new version
value for FirstThatObservesClassProperty.

Source/WebKit:

• UIProcess/ios/WKStylusDeviceObserver.mm:

(-[WKStylusDeviceObserver start]):
(-[WKStylusDeviceObserver stop]):

Location:

trunk/Source

Files:

• WebCore/ChangeLog (modified) (1 diff)
• WebCore/platform/cocoa/VersionChecks.h (modified) (1 diff)
• WebKit/ChangeLog (modified) (1 diff)
• WebKit/UIProcess/ios/WKStylusDeviceObserver.mm (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2020-11-02  Devin Rousso  <drousso@apple.com>
+
+        guard UIScribbleInteraction class property observing behind a LOA check
+        https://bugs.webkit.org/show_bug.cgi?id=218463
+        <rdar://problem/70747966>
+
+        Reviewed by Tim Horton.
+
+        Some apps appear to swizzle `-[NSObject addObserver:forKeyPath:options:context:]` without
+        support for the fact that the object can be a class rather than an instance and therefore
+        crash. Use a LOA check to guard observing `+[UIScribbleInteraction isPencilInputExpected]`
+        so that this doesn't happen, but only until the apps update, at which point they can fix it.
+
+        * platform/cocoa/VersionChecks.h:
+        This appears to be the first instance of observing a class property, so add a new version
+        value for `FirstThatObservesClassProperty`.
+
 2020-11-02  Chris Dumez  <cdumez@apple.com>
 

trunk/Source/WebCore/platform/cocoa/VersionChecks.h

@@ -66 +66 @@
     FirstVersionWithiOSAppsOnMacOS = DYLD_IOS_VERSION_FIRST_WITH_IOS_APPS_ON_MACOS,
     FirstWithDataURLFragmentRemoval = DYLD_IOS_VERSION_14_5,
+    FirstThatObservesClassProperty = DYLD_IOS_VERSION_14_5,
 #elif PLATFORM(MAC)
     FirstWithNetworkCache = DYLD_MACOSX_VERSION_10_11,

trunk/Source/WebKit/ChangeLog

@@ +1 @@
+2020-11-02  Devin Rousso  <drousso@apple.com>
+
+        guard UIScribbleInteraction class property observing behind a LOA check
+        https://bugs.webkit.org/show_bug.cgi?id=218463
+        <rdar://problem/70747966>
+
+        Reviewed by Tim Horton.
+
+        Some apps appear to swizzle `-[NSObject addObserver:forKeyPath:options:context:]` without
+        support for the fact that the object can be a class rather than an instance and therefore
+        crash. Use a LOA check to guard observing `+[UIScribbleInteraction isPencilInputExpected]`
+        so that this doesn't happen, but only until the apps update, at which point they can fix it.
+
+        * UIProcess/ios/WKStylusDeviceObserver.mm:
+        (-[WKStylusDeviceObserver start]):
+        (-[WKStylusDeviceObserver stop]):
+
 2020-11-02  James Savage  <james.savage@apple.com>
 

trunk/Source/WebKit/UIProcess/ios/WKStylusDeviceObserver.mm

@@ -31 +31 @@
 #import "WebProcessProxy.h"
 #import <UIKit/UIScribbleInteraction.h>
+#import <WebCore/VersionChecks.h>
 #import <wtf/RetainPtr.h>
 #import <wtf/Seconds.h>
@@ -84 +85 @@
         return;
 
-    [[UIScribbleInteraction class] addObserver:self forKeyPath:@"isPencilInputExpected" options:NSKeyValueObservingOptionInitial context:nil];
+    if (WebCore::linkedOnOrAfter(WebCore::SDKVersion::FirstThatObservesClassProperty))
+        [[UIScribbleInteraction class] addObserver:self forKeyPath:@"isPencilInputExpected" options:NSKeyValueObservingOptionInitial context:nil];
 }
 
@@ -93 +95 @@
         return;
 
-    [[UIScribbleInteraction class] removeObserver:self forKeyPath:@"isPencilInputExpected"];
+    if (WebCore::linkedOnOrAfter(WebCore::SDKVersion::FirstThatObservesClassProperty))
+        [[UIScribbleInteraction class] removeObserver:self forKeyPath:@"isPencilInputExpected"];
 }