CHCSV importer memory issue on NSBlockOperation - objective-c

Question

I'm on XCode 8.2, Objective-C, OSX (not iOS), ARC enabled.
I'm importing a large CSV file in a custom NSBlockOperation with DaveDelongs CHCSV parser. My problem: The memory is not freed after the operation is done. Even if i do NOT save the parsed NSArray* the same happens.
Here is the essential part of the code:
SHImportDataOperation.m (custom NSBlockOperation)
// CHCSV parser delegate
#interface Delegate : NSObject <CHCSVParserDelegate>
#property (readonly) NSArray *lines; // <-- parsing result is stored here
#property (readonly) NSString *errorMessage;
#property unsigned long long filesize;
#property SHGlobalAppData* global;
#end
#implementation SHImportDataOperation
#synthesize finished = _finished;
#synthesize executing = _executing;
- (void)main
{
// ###############################
// UI stuff
dispatch_async(dispatch_get_main_queue(), ^{
// Hide controls
[_global.dataFile setFileDropped:NO]; // _global.dataFile is an NSObject with relevant fileInformation
});
// ###############################
// Import CSV
if (![self importCSV:_global.dataFile])
{
[self breakImportData]; // Cleanup
return;
}
}
// ###############################
// Finishing Import Data
// UI stuff
dispatch_async(dispatch_get_main_queue(), ^{
// Show controls
[_global.dataFile setFileDropped:YES];
// Show OK
[_global.dataFile setImported:YES];
// Cleanup
[self finishOperation];
});
}
// ################################################
// cleanup
- (void)finishOperation
{
[self willChangeValueForKey:#"isFinished"];
[self willChangeValueForKey:#"isExecuting"];
_executing = NO;
_finished = YES;
[self didChangeValueForKey:#"isExecuting"];
[self didChangeValueForKey:#"isFinished"];
}
// ################################################
- (BOOL)importCSV:(SHDataModelData *)dataFile
{
encoding = NSMacOSRomanStringEncoding;
NSString* delimiter = #",";
unichar delimiterUnichar = [delimiter characterAtIndex:0];
// ###############################
NSInputStream* stream = [NSInputStream inputStreamWithFileAtPath:dataFile.filePath];
CHCSVParser* p = [[CHCSVParser alloc] initWithInputStream:stream usedEncoding:&encoding delimiter:delimiterUnichar];
Delegate * d = [[Delegate alloc] init];
[d setGlobal:_global]; // Reference needed for UI progress bar
[p setDelegate:d];
[p setFilepath:dataFile.filePath];
[p parse];
//NSLog(#"Result: %#",d.lines);
// Save imported data
//[dataFile setImportData:d.lines]; // Even if not saved, memory is not free'd after operation
// Even if i nil everything, memory is not freed.
[d setGlobal:nil];
[p setDelegate:nil];
d = nil;
p = nil;
return true;
}
And this is how the operation is started:
NSOperationQueue* operationImportQueue = [NSOperationQueue new];
SHImportLayoutOperation *importLayoutOperation = [[SHImportLayoutOperation alloc] init];
[importLayoutOperation setGlobal:[self theAppDataObject]];
SHImportDataOperation *importDataOperation = [[SHImportDataOperation alloc] init];
[importDataOperation setGlobal:[self theAppDataObject]];
NSBlockOperation *importDoneCompletionOperation = [NSBlockOperation blockOperationWithBlock:^{
[self continueWithStuff];
}];
[importDoneCompletionOperation addDependency:importDataOperation];
[importDoneCompletionOperation addDependency:importLayoutOperation];
[operationImportQueue addOperation:importDoneCompletionOperation];
[operationImportQueue addOperation:importDataOperation];
[operationImportQueue addOperation:importLayoutOperation];
Edit 1:
After further testing i can confirm the NSBlockOperation is successfully performed and removed from memory.