iOS的swift代码：
if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (void *)&outDictionary) == noErr)
完整代码是：
//if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (CFTypeRef *)&outDictionary) == noErr)
//if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (void *)&outDictionary) == noErr)
if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (void *)&outDictionary) == noErr)
{
// Stick these default values into keychain item if nothing found.
[self resetKeychainItem];
// Add the generic attribute and the keychain access group.
[keychainItemData setObject:identifier forKey:(id)kSecAttrGeneric];
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren’t signed, so there’s no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[keychainItemData setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
}
}
else
{
// load the saved data from Keychain.
self.keychainItemData = [self secItemFormatToDictionary:outDictionary];
}
出现警告：
KeychainItemWrapper/KeychainItemWrapper.m:134:13: Logical not is only applied to the left hand side of this comparison
如图：
c++ – warning: Wlogical-not-parentheses – Stack Overflow
61271 – 10 * possible coding error with logical not (!)
通过看完整代码，感觉逻辑应该是：
针对于：
SecItemCopyMatching((CFDictionaryRef)tempQuery, (void *)&outDictionary) == noErr
去取反的
所以，感觉应该使用建议：
Add parentheses after the ‘!’ to evaluate the comparison first
而不是：
Add parentheses around left hand side expression to silence this warning
即：
【总结】
改为：
if (! (SecItemCopyMatching((CFDictionaryRef)tempQuery, (void *)&outDictionary) == noErr))
即可。
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