Changeset 207397 in webkit

Timestamp:

Oct 16, 2016 6:28:51 PM (8 years ago)

Author:

Chris Dumez

Message:

REGRESSION (r206750): Crash when pressing Caps Lock if “Use the Caps Lock key to switch to and from U.S.” is selected in Input Sources preferences
​https://bugs.webkit.org/show_bug.cgi?id=163506
<rdar://problem/28792483>

Reviewed by Darin Adler.

As per the NSEvent documentation [1], calling [NSEvent characters] is only
valid on key up / key down events and will raise an NSInternalInconsistencyException
if accessed on any other kind of event object. The crash happens when keyForKeyEvent()
is called with the third kind of key event (NSFlagsChanged) which is used for
detecting modifier keys. We normally detect the modifier key and return early before
calling [NSEvent characters]. However, in some rare cases, we fail to detect the
modifier key and we fall through.

To address the issue, we now return "Unidentified" for NSFlagsChanged events, if we
fail to detect the modifier key and before calling [NSEvent characters].

[1] ​https://developer.apple.com/reference/appkit/nsevent/1534183-characters

No new test, not easily testable.

• platform/mac/PlatformEventFactoryMac.mm:

(WebCore::keyForKeyEvent):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/mac/PlatformEventFactoryMac.mm (modified) (8 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-10-16  Chris Dumez  <cdumez@apple.com>
+
+        REGRESSION (r206750): Crash when pressing Caps Lock if “Use the Caps Lock key to switch to and from U.S.” is selected in Input Sources preferences
+        https://bugs.webkit.org/show_bug.cgi?id=163506
+        <rdar://problem/28792483>
+
+        Reviewed by Darin Adler.
+
+        As per the NSEvent documentation [1], calling [NSEvent characters] is only
+        valid on key up / key down events and will raise an NSInternalInconsistencyException
+        if accessed on any other kind of event object. The crash happens when keyForKeyEvent()
+        is called with the third kind of key event (NSFlagsChanged) which is used for
+        detecting modifier keys. We normally detect the modifier key and return early before
+        calling [NSEvent characters]. However, in some rare cases, we fail to detect the
+        modifier key and we fall through.
+
+        To address the issue, we now return "Unidentified" for NSFlagsChanged events, if we
+        fail to detect the modifier key and before calling [NSEvent characters].
+
+        [1] https://developer.apple.com/reference/appkit/nsevent/1534183-characters
+
+        No new test, not easily testable.
+
+        * platform/mac/PlatformEventFactoryMac.mm:
+        (WebCore::keyForKeyEvent):
+
 2016-10-16  Darin Adler  <darin@apple.com>
 

trunk/Source/WebCore/platform/mac/PlatformEventFactoryMac.mm

@@ -37 +37 @@
 #import <mach/mach_time.h>
 #import <wtf/ASCIICType.h>
+#import <wtf/mac/AppKitCompatibilityDeclarations.h>
 
 namespace WebCore {
@@ -222 +223 @@
 static inline String textFromEvent(NSEvent* event)
 {
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
     if ([event type] == NSEventTypeFlagsChanged)
-#else
-    if ([event type] == NSFlagsChanged)
-#endif
         return emptyString();
     return String([event characters]);
@@ -233 +230 @@
 static inline String unmodifiedTextFromEvent(NSEvent* event)
 {
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
     if ([event type] == NSEventTypeFlagsChanged)
-#else
-    if ([event type] == NSFlagsChanged)
-#endif
         return emptyString();
     return String([event charactersIgnoringModifiers]);
@@ -265 +258 @@
     }
 
+    // If the event is an NSEventTypeFlagsChanged events and we have not returned yet then this means we could not
+    // identify the modifier key. We return now and report the key as "Unidentified".
+    // Note that [event characters] below raises an exception if called on an NSEventTypeFlagsChanged event.
+    if ([event type] == NSEventTypeFlagsChanged)
+        return ASCIILiteral("Unidentified");
+
     // If more than one key is being pressed and the key combination includes one or more modifier keys
     // that result in the key no longer producing a printable character (e.g., Control + a), then the
@@ -270 +269 @@
     // typed with the default keyboard layout with no modifier keys except for Shift and AltGr applied.
     // https://w3c.github.io/uievents/#keys-guidelines
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
     bool isControlDown = ([event modifierFlags] & NSEventModifierFlagControl);
-#else
-    bool isControlDown = ([event modifierFlags] & NSControlKeyMask);
-#endif
     NSString *s = isControlDown ? [event charactersIgnoringModifiers] : [event characters];
     auto length = [s length];
@@ -501 +496 @@
 String keyIdentifierForKeyEvent(NSEvent* event)
 {
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
     if ([event type] == NSEventTypeFlagsChanged) {
-#else
-    if ([event type] == NSFlagsChanged) {
-#endif
         switch ([event keyCode]) {
             case 54: // Right Command
@@ -693 +684 @@
     OptionSet<PlatformEvent::Modifier> modifiers;
 
-#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101200
     if (event.modifierFlags & NSEventModifierFlagShift)
         modifiers |= PlatformEvent::Modifier::ShiftKey;
@@ -704 +694 @@
     if (event.modifierFlags & NSEventModifierFlagCapsLock)
         modifiers |= PlatformEvent::Modifier::CapsLockKey;
-#else
-    if (event.modifierFlags & NSShiftKeyMask)
-        modifiers |= PlatformEvent::Modifier::ShiftKey;
-    if (event.modifierFlags & NSControlKeyMask)
-        modifiers |= PlatformEvent::Modifier::CtrlKey;
-    if (event.modifierFlags & NSAlternateKeyMask)
-        modifiers |= PlatformEvent::Modifier::AltKey;
-    if (event.modifierFlags & NSCommandKeyMask)
-        modifiers |= PlatformEvent::Modifier::MetaKey;
-    if (event.modifierFlags & NSAlphaShiftKeyMask)
-        modifiers |= PlatformEvent::Modifier::CapsLockKey;
-#endif
 
     return modifiers;