Error in file provider app extension - ios

Question

I'm developing an app extension for open mode for my document management application. I have already implemented the import mode which is working fine. But in the open mode , when a third party application tries to open any documents from my storage provider, the following methods of file provider is executing multiple times,kind of an inifinite execution and in turn resulting in a memory warning exception.
- (instancetype)init
- (void)startProvidingItemAtURL:(NSURL *)url completionHandler:(void (^)(NSError *))completionHandler
And also for your reference the complete code fo file provider as follows
- (NSFileCoordinator *)fileCoordinator {
NSFileCoordinator *fileCoordinator = [[NSFileCoordinator alloc] init];
[fileCoordinator setPurposeIdentifier:[self providerIdentifier]];
return fileCoordinator;
}
- (instancetype)init {
self = [super init];
if (self) {
[self.fileCoordinator coordinateWritingItemAtURL:[self documentStorageURL] options:0 error:nil byAccessor:^(NSURL *newURL) {
// ensure the documentStorageURL actually exists
NSError *error = nil;
[[NSFileManager defaultManager] createDirectoryAtURL:newURL withIntermediateDirectories:YES attributes:nil error:&error];
}];
}
return self;
}
- (void)providePlaceholderAtURL:(NSURL *)url completionHandler:(void (^)(NSError *error))completionHandler {
// Should call + writePlaceholderAtURL:withMetadata:error: with the placeholder URL, then call the completion handler with the error if applicable.
NSString* fileName = [url lastPathComponent];
NSURL *placeholderURL = [NSFileProviderExtension placeholderURLForURL:[self.documentStorageURL URLByAppendingPathComponent:fileName]];
NSUInteger fileSize = 0;
// TODO: get file size for file at <url> from model
[self.fileCoordinator coordinateWritingItemAtURL:placeholderURL options:0 error:NULL byAccessor:^(NSURL *newURL) {
NSDictionary* metadata = #{ NSURLFileSizeKey : #(fileSize)};
[NSFileProviderExtension writePlaceholderAtURL:placeholderURL withMetadata:metadata error:NULL];
}];
if (completionHandler) {
completionHandler(nil);
}
}
- (void)startProvidingItemAtURL:(NSURL *)url completionHandler:(void (^)(NSError *))completionHandler {
// Should ensure that the actual file is in the position returned by URLForItemWithIdentifier:, then call the completion handler
NSError* error = nil;
__block NSError* fileError = nil;
//getting the actual fiile from the shared container
NSURL *storeURL = [[NSFileManager defaultManager] containerURLForSecurityApplicationGroupIdentifier:#"group.company.test.NBox"];
storeURL = [storeURL URLByAppendingPathComponent:[url.path lastPathComponent]];
NSData* fileData = [NSData dataWithContentsOfFile:[storeURL path]];
// TODO: get the contents of file at <url> from model
//Writing the file data to the documentStorage location
//[self.fileCoordinator coordinateWritingItemAtURL:url options:0 error:&error byAccessor:^(NSURL *newURL) {
[fileData writeToURL:url options:0 error:&fileError];
//}];
if (error!=nil) {
completionHandler(error);
} else {
completionHandler(fileError);
}
}
- (void)itemChangedAtURL:(NSURL *)url {
// Called at some point after the file has changed; the provider may then trigger an upload
// TODO: mark file at <url> as needing an update in the model; kick off update process
NSLog(#"Item changed at URL %#", url);
}
- (void)stopProvidingItemAtURL:(NSURL *)url {
// Called after the last claim to the file has been released. At this point, it is safe for the file provider to remove the content file.
// Care should be taken that the corresponding placeholder file stays behind after the content file has been deleted.
[self.fileCoordinator coordinateWritingItemAtURL:url options:NSFileCoordinatorWritingForDeleting error:NULL byAccessor:^(NSURL *newURL) {
[[NSFileManager defaultManager] removeItemAtURL:newURL error:NULL];
}];
[self providePlaceholderAtURL:url completionHandler:NULL];
}
Thanks,
Vsh

Answer 1

I'm also trying to develop an app extension for open mode. I haven't been successful yet but I don't get the infinite execution. Looking at your code, it's possible that storeURL in startProvidingItemAtURL: points to something inside your container. If so, then the assignment to fileData would trigger an infinite recursion.
As a test, try setting fileData with a test message like this:
NSString *message = [NSString stringWithFormat:#"This is a test."];
NSData *fileData = [NSKeyedArchiver archivedDataWithRootObject:message];
If that works, then it's a problem with storeURL and you'll have to figure out some different location to get the data.
(Incidentally, I noticed that you commented out the file coordinator in startProvidingItemAtURL:. I also ended up doing that to prevent deadlocks and because there's a note in the documentation that says "Do not use file coordination inside this method." But it's very confusing because the template code for file providers puts the file coordinator in that method!)