Remove Core Data from iCloud fails

问题:

I'm trying to remove Core Data from iCloud using [NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:options:error:]. But I get strange output:

__93+[NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:options:error:]_block_invoke(1982):
CoreData: Ubiquity:  Unable to move content directory to new location:
file:///private/var/mobile/Library/Mobile%20Documents/<UBIQUITY_ID>/    
New: file:///private/var/mobile/Library/Mobile%20Documents/OldUbiquitousContent-mobile~C9439AD0-1E87-4977-9C68-0674F5E2E93B
Error Domain=NSCocoaErrorDomain Code=513 "The operation couldn’t be completed.
(Cocoa error 513.)" UserInfo=0x181ab790 {NSSourceFilePathErrorKey=/private/var/mobile/Library/Mobile Documents/<UBIQUITY_ID>,     
NSUserStringVariant=(
    Move
), NSFilePath=/private/var/mobile/Library/Mobile Documents/<UBIQUITY_ID>,
NSDestinationFilePath=/private/var/mobile/Library/Mobile Documents/OldUbiquitousContent-mobile~C9439AD0-1E87-4977-9C68-0674F5E2E93B,
NSUnderlyingError=0x181aab50 "The operation couldn’t be completed. Operation not permitted"}

What does it mean?

How to avoid it? I'm working on iCloud disable/enable feature. Details HERE

UPDATE:

  NSDictionary *iCloudOptions =
  [NSDictionary dictionaryWithObjectsAndKeys:kICloudContentNameKey, NSPersistentStoreUbiquitousContentNameKey,
   iCloudURL, NSPersistentStoreUbiquitousContentURLKey, nil];

// self.lastICloudStoreURL stores NSPersistentStore.URL after stack setup
  BOOL result = [NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:self.lastICloudStoreURL
                                                                                     options:iCloudOptions
                                                                                       error:&error];

回答1:

Normally (before iOS7), you take the ubiquitousContentURL value from [fileManager URLForUbiquityContainerIdentifier:nil]; and pass it as an option called NSPersistentStore UbiquitousContentURLKey, and this is how iCloud know where to keep all of your data in the iCloud account.

In iOS 7 and Mac OS X we don't need to pass a value for that at all, and Apple call URLForUbiquitous ContainerIdentifier automatically under the hood for you.

So the solution looks like this:

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:kICloudContentNameKey, NSPersistentStoreUbiquitousContentNameKey, nil];
NSURL *storeURL = [NSPersistentStore MR_urlForStoreName:[MagicalRecord defaultStoreName]];
BOOL result = [NSPersistentStoreCoordinator removeUbiquitousContentAndPersistentStoreAtURL:storeURL options:options error:&error];

I suggest you to check WWDC 2013 session 207 to get this things clearly.

回答2:

NSCocoaErrorDomain error 513 is defined in FoundationErrors.h as NSFileWriteNoPermissionError. You don't have the required permissions to write to the location.

This can happen if a managed object context is still using objects that are backed by this store. The context is actively using the file that is being moved, which results in a NSFileCoordinator conflict. Two things are trying to access the file with write permission at the same time.

回答3:

The removeUbiquitousContentAndPersistentStoreAtURL:options:error: method deletes all of the user's local and cloud data—this is probably not what you want. Instead, migrate your store to a new location on disk and use the NSPersistentStoreRemoveUbiquitousMetadataOption option with the migratePersistentStore:toURL:options:withType:error: method.

See Disabling iCloud Persistence at Removing an iCloud-enabled Persistent Store in the iCloud Programming Guide for Core Data.