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当最新的 MacBook Pro 推出时，我在我的应用程序中添加了 Touch Bar 支持。后来我做了各种小的改进，包括在有意义的地方自定义转义键。发布该更新后，当应用程序尝试更新转义键时，我开始收到崩溃报告。

这是一个例子：

Exception Type:  SIGBUS
Exception Codes: BUS_ADRERR at 0x7fff54a05ff8
Crashed Thread:  0

Application Specific Information:
Selector name found in current argument registers: objectForKey:

Thread 0 Crashed:
0   Foundation                           0x00007fffacbaea98 -[NSConcreteMapTable objectForKey:] + 21
1   Foundation                           0x00007fffacbfc019 -[NSISEngine outgoingRowHeadForRemovingConstraintWithMarker:] + 214
2   Foundation                           0x00007fffacbfbb4c -[NSISEngine removeConstraintWithMarker:] + 479
3   Foundation                           0x00007fffacbf76a6 -[NSISEngine _flushPendingRemovals] + 615
4   Foundation                           0x00007fffacbf4b06 -[NSISEngine withBehaviors:performModifications:] + 197
5   AppKit                               0x00007fffa8c83760 -[NSView(NSConstraintBasedLayout) _withAutomaticEngineOptimizationDisabled:] + 69
6   AppKit                               0x00007fffa8d129dd -[NSView(NSConstraintBasedLayout) removeConstraints:] + 276
7   AppKit                               0x00007fffa8c88f9e -[NSView(NSConstraintBasedLayout) _constraints_snipDangliesWithForce:] + 595
8   AppKit                               0x00007fffa8c82d9e -[NSView _setSuperview:] + 1076
9   AppKit                               0x00007fffa8c88945 -[NSView removeFromSuperview] + 446
10  AppKit                               0x00007fffa9593eef -[NSTouchBarEscapeKeyViewController setTouchBarItem:] + 145
11  AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438
12  AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438
13  AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438
…
509 AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438
510 AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438
511 AppKit                               0x00007fffa9176bf5 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438

为了简洁起见，我删除了大约 500 行——所有这些都是调用[NSApplicationFunctionRowController _updateEscapeKeyItem] + 438

这是另一个简短的报告。这是我最常见的崩溃。它实际上调用了我自己的代码，尽管我怀疑它调用的代码不是实际问题：

Exception Type:  SIGBUS
Exception Codes: BUS_ADRERR at 0x7fff5b8c2f74
Crashed Thread:  0

Thread 0 Crashed:
0   CoreText                             0x00007fffc87d2e8d _ZNK3OTL7GCommon9NthLookupEj + 41
1   CoreText                             0x00007fffc87d658b _ZNK3OTL4GPOS12ApplyLookupsER8TRunGlueiRNS_12GlyphLookupsE + 155
2   CoreText                             0x00007fffc87d5f53 _ZN26TOpenTypePositioningEngine12PositionRunsER9SyncStateR13KerningStatus + 839
3   CoreText                             0x00007fffc8823920 _ZN14TKerningEngine14PositionGlyphsER8TRunGlue11ShapingTypePK10__CFString + 168
4   CoreText                             0x00007fffc87ddcf7 CTFontTransformGlyphs + 463
5   UIFoundation                         0x00007fffd9d2a795 __NSStringDrawingEngine + 7348
6   UIFoundation                         0x00007fffd9d315ea -[NSAttributedString(NSExtendedStringDrawing) boundingRectWithSize:options:context:] + 605
7   UIFoundation                         0x00007fffd9d31efd -[NSAttributedString(NSExtendedStringDrawing) boundingRectWithSize:options:] + 32
8   AppKit                               0x00007fffc4e711cb -[NSAttributedString(NSStringDrawingExtension) _sizeWithSize:] + 55
9   AppKit                               0x00007fffc4e710ff -[NSButtonCell(NSButtonCellPrivate) _titleSizeWithSize:] + 97
10  AppKit                               0x00007fffc4e70eab -[NSButtonCell(NSButtonCellPrivate) _alignedTitleRectWithRect:] + 235
11  AppKit                               0x00007fffc4e25162 -[NSButtonCell cellSizeForBounds:] + 918
12  AppKit                               0x00007fffc4da2a21 -[NSCell cellSize] + 68
13  AppKit                               0x00007fffc4da295a -[NSControl sizeToFit] + 53
14  AppKit                               0x00007fffc520392c +[NSButton(NSButtonConvenience) _buttonWithTitle:image:target:action:] + 421
15  AppKit                               0x00007fffc5203a05 +[NSButton(NSButtonConvenience) buttonWithTitle:target:action:] + 199
16  Deliveries                           0x0000000103b4c655 +[JUNTouchBar cancelButtonItemWithIdentifier:] (JUNTouchBar.m:75)
17  Deliveries                           0x0000000103b67e9b -[JUNEditWindowController touchBar:makeItemForIdentifier:] (JUNEditWindowController.m:183)
18  AppKit                               0x00007fffc57d7d2a __32-[NSTouchBar itemForIdentifier:]_block_invoke + 34
19  AppKit                               0x00007fffc4e71bd0 +[NSAppearance _performWithCurrentAppearance:usingBlock:] + 79
20  AppKit                               0x00007fffc57d7b9b -[NSTouchBar itemForIdentifier:] + 1158
21  AppKit                               0x00007fffc57d868e -[NSTouchBar(NSEscapeKeyReplacementOld) escapeKeyReplacementItem] + 51
22  AppKit                               0x00007fffc5250e80 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 238
23  AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439
24  AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439
25  AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439
…
509 AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439
510 AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439
511 AppKit                               0x00007fffc5250f49 -[NSApplicationFunctionRowController _updateEscapeKeyItem] + 439

我的touchBar:makeItemForIdentifier:方法就是这样：

- (nullable NSTouchBarItem *)touchBar:(NSTouchBar *)touchBar makeItemForIdentifier:(NSTouchBarItemIdentifier)identifier {

    if ([identifier isEqualToString:JUNTouchBarItemIdentifierCancel]) {
        NSCustomTouchBarItem *item = [JUNTouchBar cancelButtonItemWithIdentifier:identifier];
        return item;
    }
    return nil;

}

这里的cancelButtonItemWithIdentifier:，也很简单：

+ (NSCustomTouchBarItem *)cancelButtonItemWithIdentifier:(NSString *)identifier {
    NSString *title = NSLocalizedString(@"Cancel", nil);
    NSButton *button = [NSButton buttonWithTitle:title target:nil action:@selector(cancelOperation:)];
    NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationGreaterThanOrEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0 constant:80.0];
    constraint.priority = 950;
    constraint.active = YES;
    NSCustomTouchBarItem *item = [[NSCustomTouchBarItem alloc] initWithIdentifier:identifier];
    item.view = button;
    return item;
}

当然，我自己无法重现此崩溃。它发生在 macOS 10.12.2 到 10.12.5 的 beta 版本中。许多报告都来自我自己测试的同一个 13" 模型。少数在他们的崩溃报告中包含评论的人大多说它是在打开一个新窗口的操作之后立即发生的（因此更改了转义键） ——一个人说它发生在一个会关闭窗口的动作之后。一个人提到在崩溃前挂起 10 秒——考虑到对同一方法的 500 次调用，这是有道理的。有几个人不止一次提到它发生了，但是当然，他们没有留下任何联系信息，所以我没有办法跟进他们。

我知道我可以通过删除我的自定义转义键来解决崩溃问题，但我不想这样做。关于我如何处理这个问题的任何其他想法？

更新：自从最初发布此内容以来，我已经更新了应用程序以删除约束，因此我创建按钮的代码与现在一样简单：

+ (NSCustomTouchBarItem *)cancelButtonItemWithIdentifier:(NSString *)identifier {
    NSString *title = JUNLocalizedString(@"Cancel", nil);
    NSButton *button = [NSButton buttonWithTitle:title target:nil action:@selector(cancelOperation:)];
    NSCustomTouchBarItem *item = [[NSCustomTouchBarItem alloc] initWithIdentifier:identifier];
    item.view = button;
    return item;
}

不幸的是，我仍然收到来自新版本的崩溃报告，具有相同的堆栈跟踪。所以我认为问题不在于我提供的按钮。

4

1 回答 1

1

对不起，没有答案，但评论太长了。

我为经历过崩溃的用户构建了一个调试版本，它调整了 _updateEscapeKeyItem 方法，试图查明崩溃的起源，由于堆栈的底部被无限递归吹走，所以不可见。

我的猜测是他们彻底改变了 10.13 的实现（他们提到了一些关于“KVO running amok”的内容），除非他们有可靠的线索，否则可能不会调查 10.12 的崩溃。

这是您可以插入的快速而肮脏的代码（主要是从How to swizzle a method of a private class借来的），它停止了无限递归。生成的崩溃报告可能更有用。

@interface NSObject (swizzle_touchbar_stuff)
@end

static NSInteger updateEscapeKeyItem = 0;

@implementation NSObject (swizzle_touchbar_stuff)
+ (void)load
{
    static dispatch_once_t onceToken = 0;
    dispatch_once(&onceToken, ^{
        Method original, swizzled;

        original = class_getInstanceMethod(objc_getClass("NSApplicationFunctionRowController"), NSSelectorFromString(@"_updateEscapeKeyItem"));
        swizzled = class_getInstanceMethod(self, @selector(sparkle_updateEscapeKeyItem));
        method_exchangeImplementations(original, swizzled);
    });
}

- (void)sparkle_updateEscapeKeyItem
{
    updateEscapeKeyItem++;
    NSLog(@"sparkle_updateEscapeKeyItem %ld", updateEscapeKeyItem);
    assert(updateEscapeKeyItem < 10);
    [(NSObject *)self sparkle_updateEscapeKeyItem];
    updateEscapeKeyItem--;
}

@end
于 2017-09-30T20:16:09.403 回答