为什么NSFontManager.availableMembers（ofFontFamily :)在Xcode 8 GM中崩溃了？

Question

我是在Xcode 8 Beta 6（8S201h）中写的：

guard let faceMembers = NSFontManager.shared().availableMembers(ofFontFamily: familyName ?? fontName) else { return nil }

它运作得很好。现在我已升级到 Xcode 8 GM Seed（8A218a） Xcode 8（8A218a），它崩溃了（EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)）。

使用调试器缩小范围，我发现NSFontManager.availableMembers(ofFontFamily:)中的某些东西真的很讨厌这个，因为它无论我放在那里都会崩溃，即使是像Helvetica Neue这样的常见（明确安装！）字体。< / p>

(lldb) po NSFontManager.shared()
<NSFontManager: 0x6100000a24c0>

(lldb) po familyName
▿ Optional<String>
  - some : "Helvetica Neue"


(lldb) po fontName
"HelveticaNeue"


(lldb) po NSFontManager.shared().availableMembers(ofFontFamily: familyName ?? fontName)
error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been returned to the state before expression evaluation.
(lldb) po NSFontManager.shared().availableMembers(ofFontFamily: familyName!)
error: Execution was interrupted, reason: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0).
The process has been returned to the state before expression evaluation.
(lldb) po NSFontManager.shared().availableMembers(ofFontFamily: "Not a real font?!")
nil

因此，当我传递一个有效的字体系列名称时，它会崩溃......但是当我将它传递给假名时，它会返回nil。

这是一个我可以解决的问题，还是 Xcode 8 GM Seed Xcode 8的问题，它将在SDK更新中解决？

浏览崩溃日志后，我看到了这种可疑：

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libswiftFoundation.dylib        0x0000000107cbb249 _TZFE10FoundationSa26_forceBridgeFromObjectiveCfTCSo7NSArray6resultRGSqGSax___T_ + 153
1   libswiftCore.dylib              0x00000001079031f3 swift_dynamicCast + 1635
2   libswiftCore.dylib              0x000000010790448b _dynamicCastFromExistential(swift::OpaqueValue*, swift::OpaqueValue*, swift::TargetExistentialTypeMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift::DynamicCastFlags) + 91
3   libswiftCore.dylib              0x0000000107903919 swift_dynamicCast + 3465
4   libswiftFoundation.dylib        0x0000000107d6a348 _TPA__TFFs15_arrayForceCastu0_rFGSax_GSaq__U_FQ_Q0_ + 56
5   libswiftFoundation.dylib        0x0000000107cbbc45 _TFEsPs10Collection3mapurfzFzWx8Iterator7Element_qd__GSaqd___ + 885
6   libswiftFoundation.dylib        0x0000000107cbb4c3 _TFs15_arrayForceCastu0_rFGSax_GSaq__ + 227
7   libswiftFoundation.dylib        0x0000000107cbb7a5 _TZFE10FoundationSa36_unconditionallyBridgeFromObjectiveCfGSqCSo7NSArray_GSax_ + 197

所以看起来它在Swift-Foundation中崩溃，在一些名为_forceBridgeFromObjectiveC的函数中......不确定这是否对任何人有帮助，但它确实在SDK /运行时内确认了它

Answer 1

在此期间我能弄清楚如何解决这个问题的唯一方法是在objective-c类中创建一个静态方法。然后我将标头导入我的桥接头并从Swift 3调用静态方法，它在那里工作正常。

希望这有助于您度过这些困难时期！

#import <Foundation/Foundation.h>
#import <Cocoa/Cocoa.h>

@interface WorkAround : NSObject

+ (NSArray *)typefacesForFontFamily:(NSString *)family;

@end


#import "WorkAround.h"

@implementation WorkAround

/// Returns an array of arrays, or nil, that contain information about
/// each typeface found for the specified font family.
+ (NSArray *)typefacesForFontFamily:(nonnull NSString *)family {
  NSFontManager *fontManager = [NSFontManager sharedFontManager];
  return [fontManager availableMembersOfFontFamily:family];
}
@end

Answer 2

Joseph E。的回答是一个很好的起点。然而，为了让它在Swift 3，Xcode 8（8A218a）中运行，我不得不采用不同的方法......

1. 子类NSFontManager（在目标C中），如果您还没有，则创建桥接头。

确保将语言更改为（目标C）。重要的是你这样做，因为它看起来you cannot directly create an objective c m files?，即使有这样做的选项。

1. 实施

FontManager.h

#import <Cocoa/Cocoa.h>

@interface FontManager : NSFontManager
    NS_ASSUME_NONNULL_BEGIN

    + (NSArray *)typefacesForFontFamily:(NSString *)family;


    NS_ASSUME_NONNULL_END
@end

FontManager.m

#import "FontManager.h"

@implementation FontManager
    NS_ASSUME_NONNULL_BEGIN

    + (NSArray *)typefacesForFontFamily:(nonnull NSString *)family {
        NSFontManager *fontManager = [self sharedFontManager];
        return [fontManager availableMembersOfFontFamily:family];
    }

    NS_ASSUME_NONNULL_END
@end

桥接-header.h

//
//  Use this file to import your target's public headers that you would like to expose to Swift.
//

#import "FontManager.h"

1. Swift 3项目中的用法

   if let fontMembers = FontManager.typefaces(forFontFamily: "Arial") as? [[Any]]  { }