EKEvent的镜像不显示数据

Question

For my EVReflection library I came to a case where a Mirror for an EKEvent did not return any information. Even when going to the complete basics a Mirror did not return anything. When you set a breakpoint after the Mirror line, you will see that there is nothing in the Mirror object. Is this a bug or am I missing something?

update: I extended the demo for getting the properties using the old Objective C objc_property_t and property_getName functions. It will return a list of properties. But then it will crash when you get the .value(forKey:

#if os(tvOS)
    // Eventkit is not supported on tvOS
#else


import XCTest
import Foundation
import EventKit


let store = EKEventStore()

class EVReflectionEventKitTests: XCTestCase {
    func testEventKit() {

        let exp = expectation(description: "eventStore")

        store.requestAccess(to: .event, completion: { (granted, error) in
            let event = EKEvent(eventStore: store)
            event.startDate = Date().addingTimeInterval(10000)
            event.title = "title"
            event.location = "here"
            event.endDate = Date().addingTimeInterval(20000)
            event.notes = "notes"

            event.calendar = store.defaultCalendarForNewEvents
            event.addAlarm(EKAlarm(absoluteDate: Date().addingTimeInterval(10000)))

            //WARNING: You will get events in your agenda! Disable next line if you don't want that
            //try? store.save(event, span: EKSpan.thisEvent, commit: true)

            let m = Mirror(reflecting: event)
            print("mirror children = \(m.children.count)")

            let oc = self.properties(event)
            print(oc)

            for p in oc {
                var value: Any? = nil
                value = event.value(forKey: p)
                print("\(p) = \(String(describing: value))")
            }

            exp.fulfill()
        })

        waitForExpectations(timeout: 10) { error in
            XCTAssertNil(error, "\(error?.localizedDescription ?? "")")
        }
    }

    func properties(_ classToInspect: NSObject) -> [String] {
        var count = UInt32()
        let classToInspect = NSURL.self
        let properties = class_copyPropertyList(classToInspect, &count)
        var propertyNames = [String]()
        let intCount = Int(count)
        for i in 0 ..< intCount {
            let property : objc_property_t = properties![i]!
            guard let propertyName = NSString(utf8String: property_getName(property)) as String? else {
                debugPrint("Couldn't unwrap property name for \(property)")
                break
            }
            propertyNames.append(propertyName)
        }

        free(properties)
        return propertyNames
    }
}

#endif

Answer 1

This appears to be intended behavior:

• The _ObjCMirror child count implementation just defers to the _getObjCCount shim, whose actual function name is specified as swift_ObjCMirror_count .
• swift_ObjCMirror_count is rigged up to just return 0 all the time when REFLECT_OBJC_IVARS is defined to a falsey value.
• Guess what the value for REFLECT_OBJC_IVARS is in the Swift source? That's right, it's set to 0 .

If it were non-zero, it'd be dumping ivars, not properties. A property's getter attribute can make it so there's no method matching the property name, and its backing ivar can also be named differently from the property, if there even is one: both of these could cause -valueForKey: to fail out. Most classes don't disable direct ivar access via key-value coding, so you might want to try dumping the ivars instead and accessing those.

You might also want to note that some classes lie about their layout, like NSURL , which was explicitly blacklisted from reflection even when reflection is enabled for Obj-C classes!

ETA: Here's an example of dumping the ivars. It's not terribly useful in this case, unfortunately.

The code to generate a dictionary based on the ivars:

func makeDictionary(describing object: AnyObject) -> Dictionary<String, Any> {
    var dict = [String: Any]()
    guard let cls = object_getClass(object) else {
        print("object has no class:", object)
        return dict
    }

    var ivarCount: UInt32 = 0
    guard let ivarsPtr: UnsafeMutablePointer<Ivar?> = class_copyIvarList(cls, &ivarCount), ivarCount > 0
    else {
        print("object has no ivars, or failed to get any:", object)
        return dict
    }

    let ivars = UnsafeBufferPointer(start: ivarsPtr, count: numericCast(ivarCount))
    for ivar in ivars {
        guard let int8Ptr = ivar_getName(ivar) else {
            print("failed to get name for ivar:", ivar as Any)
            continue
        }

        let name = String(cString: int8Ptr)
        let value = object_getIvar(object, ivar)
        print("value for \(name):", value as Any)
        dict[name] = value ?? object.value(forKey: name) ?? NSNull()
    }
    return dict
}

And the output for an event created as described in your question (manually hard-wrapped for ease of review):

dictionary version based on direct ivar access: 
["isYearlessLeapMonthBirthday": 0
, "_birthdayPersonID": 0
, "_sliceDate": <null>
, "nameForBirthday": <null>
, "_futureLocalUidForSliceChild": <null>
, "isYearlessBirthday": 0
, "_cachedDuration": <null>
, "_cachedStartOfDayForStartDate": <null>
, "_isPhantom": 0
, "lunarCalendarString": <null>
, "_cachedIsMultiDayTimedEvent": <null>
, "_cachedTimeValuesCalendar": <null>
, "birthdayTitle": <null>
, "_cachedStartOfDayForEndDate": <null>
, "_cachedDaysSpanned": <null>
, "_cachedJunkStatus": 0
, "sliceParentID": <null>
, "participantsStatus": 0
]

Answer 2

I made a SERIALIZER.SWIFT class, like the example in github you provided:

import Foundation
import EventKit
import EVReflection

class serializedEvent: EVObject {
var myEvent: EKEvent = EKEvent(eventStore: globalStore)
//globalstore is an EKEventstore global object

---

then in one of my controllers i do (i just have a full event named: event created with alarms of type EKalarms and recurrency Rule of EKRecurrencyRule type):

print("event before serialization :")
  print(event)
  let serEvent: serializedEvent = serializedEvent()
  serEvent.myEvent=event

  let jsonEvent = serEvent.toJsonString()

  let newEvent = serializedEvent(json: jsonEvent).myEvent
  print("newEvent: =")
  print(newEvent)

This is a real example output :

event before serialization :
   EKEvent <0x174130040>
   {
     EKEvent <0x174130040>
    {    title =        Matrimonio; 
    location =  ; 
        calendar =  EKCalendar <0x1740b4d60> {title = Calendario; type = CalDAV; allowsModify = YES; color = #029ae4;}; 
       alarms =         (
      "EKAlarm <0x1740d9d00> {triggerInterval = -54000.000000}",
      "EKAlarm <0x1740d8950> {triggerInterval = 0.000000}"
  ); 
     URL =          (null); 
 lastModified = 2016-06-06 15:15:17 +0000; 
 startTimeZone =    (null); 
 startTimeZone =    (null) 
 }; 
 location =     ; 
 structuredLocation =   (null); 
 startDate =    2009-06-06 22:00:00 +0000; 
 endDate =      2009-06-07 21:59:59 +0000; 
 allDay =       1; 
 floating =     1; 
 recurrence =   EKRecurrenceRule <0x1702b2c00> RRULE FREQ=YEARLY;INTERVAL=1;BYMONTH=6;BYMONTHDAY=7; 
 attendees =    (null); 
 travelTime =   (null); 
 startLocation =    (null);
   };
  2017-04-28 21:23:25.226855 InstaEvent Share[19166:5967595] ERROR: 
   Unexpected type while converting value for JsonSerialization: 
  EKEvent <0x174130040>
  {
 EKEvent <0x174130040>
  {  title =        Matrimonio; 
    location =  ; 
     calendar =     EKCalendar <0x1740b4d60> {title = Calendario; type 
  = CalDAV; allowsModify = YES; color = #029ae4;}; 
     alarms =       (
    "EKAlarm <0x1740d9d00> {triggerInterval = -54000.000000}",
    "EKAlarm <0x1740d8950> {triggerInterval = 0.000000}"
  ); 
      URL =             (null); 
 lastModified = 2016-06-06 15:15:17 +0000; 
 startTimeZone =    (null); 
 startTimeZone =    (null) 
 }; 
 location =     ; 
 structuredLocation =   (null); 
 startDate =    2009-06-06 22:00:00 +0000; 
 endDate =      2009-06-07 21:59:59 +0000; 
 allDay =       1; 
 floating =     1; 
     recurrence =   EKRecurrenceRule <0x1702b2c00> RRULE 
     FREQ=YEARLY;INTERVAL=1;BYMONTH=6;BYMONTHDAY=7; 
 attendees =    (null); 
 travelTime =   (null); 
 startLocation =    (null);
  };

 newEvent: =
  EKEvent <0x174130040>
 {
     EKEvent <0x174130040>
 {   title =        Matrimonio; 
       location =   ; 
       calendar =   EKCalendar <0x1740b4d60> {title = Calendario; type 
     = CalDAV; allowsModify = YES; color = #029ae4;}; 
       alarms =         (
      "EKAlarm <0x1740d9d00> {triggerInterval = -54000.000000}",
      "EKAlarm <0x1740d8950> {triggerInterval = 0.000000}"
  ); 
     URL =          (null); 
      lastModified = 2016-06-06 15:15:17 +0000; 
     startTimeZone =    (null); 
     startTimeZone =    (null) 
  }; 
 location =     ; 
 structuredLocation =   (null); 
 startDate =    2009-06-06 22:00:00 +0000; 
 endDate =      2009-06-07 21:59:59 +0000; 
 allDay =       1; 
 floating =     1; 
 recurrence =   EKRecurrenceRule <0x1702b2c00> RRULE 
  FREQ=YEARLY;INTERVAL=1;BYMONTH=6;BYMONTHDAY=7; 
 attendees =    (null); 
 travelTime =   (null); 
 startLocation =    (null);
  };

but when we ask if it has alarms (and it should have, looking at output)

print(newEvent.hasAlarms)

it fails with

 19170:5969208] -[__NSCFString hasAlarms]: unrecognized selector sent to instance 0x17425d340

This is tricky :(

EDIT : if in the SERIALIZER.SWITF class i add : extension EKEvent: EVReflectable { } then the newEvent is empty.

..really tricky :D

Victor