IOS NSString 内存泄漏

Question

Hi I am having trouble figuring out the cause of a memory leak and I'am starting to wonder if maybe its some sort of IOS bug? The leak appears almost randomly and the stack trace for the leak within the debugger tool shows no methods that I have physically coded? The leaks instrument screen shot is below! Thanks!

Here's the first possible culprit!

#import "BreakfastViewController.h"
#import "AppDelegate.h"
#import "CustomCell.h"
#import "Recipe.h"
#import "RecipeAzure.h"
#import "DetailViewController.h"

@interface BreakfastViewController ()

@end

@implementation BreakfastViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];


    // Do any additional setup after loading the view.
    _tv.dataSource = self;
    _tv.delegate = self;
    _ai = [[AzureInteraction alloc] initAzureInteraction];
    _ai.delegate = self;
    _searchBar.delegate = self;

    self.ai.busyUpdate = ^(BOOL busy)
    {
        if (busy)
        {

        } else
        {

        }
    };

    [_ai getBreakfasts:nil];


}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(void)update
{


}
-(BOOL)canBecomeFirstResponder {
    return YES;
}

-(void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self becomeFirstResponder];
}

- (void)viewWillDisappear:(BOOL)animated {
    [self resignFirstResponder];
    [super viewWillDisappear:animated];
}
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    if (motion == UIEventSubtypeMotionShake)
    {
        [_ai getBreakfasts:nil];


        NSLog(@"SHAKE");
    }
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    NSLog(@"breakfast sections   %d",[_ai breakfastCount]);
   NSInteger c = [_ai breakfastCount];
    return c;
}



- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
      NSLog(@"breakfast sections   %d",[_ai breakfastCount]);
    RecipeAzure *r = [_ai getBreakfastAtIndex:indexPath];
    CustomCell *c = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
    [c.imageView setContentMode:UIViewContentModeScaleAspectFit];
    if(r.img64 != nil)
    {
        NSString *str = r.img64;
        NSData *data = [[NSData alloc] initWithBase64EncodedString:str options:0];

        c.RecipeImage.image = [UIImage imageWithData:data];
    }
    c.RecipeTitle.text = r.title;
    c.IngrediantsLabel.text = r.ingrediants;
    return c;
}

-(void)userFinished:(NSString*)title:(NSString*)ingrediants:(NSString*)method:(NSString*)password:
(NSString*)image
{
    RecipeAzure *createdRecipe = [[RecipeAzure alloc]init];

    createdRecipe.title = title;
    createdRecipe.ingrediants = ingrediants;
    createdRecipe.method = method;
    createdRecipe.password = password;
    createdRecipe.img64 = image;
    createdRecipe.type = @"breakfast";
    NSLog(@"GT HERE");
    [_ai uploadRecipe:createdRecipe];

}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{

    if ([[segue identifier] isEqualToString:@"createBreakfast"])
    {

        CreateRecipeViewController *crvc = [segue destinationViewController];


        crvc.delegate = self;
    }
    if ([[segue identifier] isEqualToString:@"detailbreakfast"])
    {

        DetailViewController *dvc = [segue destinationViewController];

        NSIndexPath *ind = [_tv indexPathForSelectedRow];
        NSLog(@"%@",[_ai getBreakfastAtIndex:ind]);
        [dvc setRecipe:[_ai getBreakfastAtIndex:ind]];
        [dvc setDelegate:self];
    }
}
-(void)updateTableview
{
    [_tv reloadData];
}
-(void)setEditChanges:(RecipeAzure *)recipe
{
    NSLog(@"OH MY GOOD %@",recipe.rid);

   [_ai updateRecipe:recipe];
}

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar
{
    NSLog(@"SEARCH BEEN PRESSED");
    [_ai getBreakfasts:searchBar.text];
    [searchBar resignFirstResponder];
}
- (void)searchBarCancelButtonClicked:(UISearchBar *) searchBar
{
    [_ai getBreakfasts:nil];
    searchBar.text = @"";
    [searchBar resignFirstResponder];
}

@end

And here's the second possible culprit!

#import "CreateRecipeViewController.h"
#import "Recipe.h"
#import "AppDelegate.h"
#import "BreakfastViewController.h"

@interface CreateRecipeViewController ()
{
    float textViewY;
    //NSString *uepassword;
}

@end

@implementation CreateRecipeViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    _Title.delegate = self;
    _Recipe.delegate = self;
    _Ingrediants.delegate = self;
    _Recipe.text = @"Enter Recipe Here...";

    _FinishedEditing.hidden = YES;
    [self.Image setContentMode:UIViewContentModeScaleAspectFit];

    if(_delegate == nil)
    {
        NSLog(@"WTF");
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (BOOL)textViewShouldBeginEditing:(UITextView *)textField
{

    return YES;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    textField.text = @"";


}
- (void)textViewDidBeginEditing:(UITextView *)textView
{
    textView.text = @"";
     textViewY = textView.frame.origin.y;

    //If we begin editing on the text field we need to move it up to make sure we can still
    //see it when the keyboard is visible.
    //
    //I am adding an animation to make this look better
    if(textView == _Recipe)
    {
        _Title.hidden = YES;
        _Ingrediants.hidden = YES;
        _Image.hidden = YES;
        _AddImage.hidden = YES;
        _FinishedEditing.hidden = NO;


    [UIView beginAnimations:@"Animate Text Field Up" context:nil];
    [UIView setAnimationDuration:.3];
    [UIView setAnimationBeginsFromCurrentState:YES];

        textViewY = _RecipeView.frame.origin.y;


    _RecipeView.frame = CGRectMake(_RecipeView.frame.origin.x,
                               80 , //this is just a number to put it above the keyboard
                               _RecipeView.frame.size.width,
                               _RecipeView.frame.size.height);

    [UIView commitAnimations];
    }

}

- (void)textFieldDidEndEditing:(UITextField *)textField
{

    [textField resignFirstResponder];



}
- (void)textViewDidEndEditing:(UITextView *)textView
{
    [textView resignFirstResponder];
}




- (IBAction)finishedPressed:(id)sender {

      [_Recipe resignFirstResponder];

           [UIView beginAnimations:@"Animate Text Field Up" context:nil];
        [UIView setAnimationDuration:.3];
        [UIView setAnimationBeginsFromCurrentState:YES];

        _RecipeView.frame = CGRectMake(_RecipeView.frame.origin.x,
                                       textViewY ,
                                       _RecipeView.frame.size.width,
                                       _RecipeView.frame.size.height);

        [UIView commitAnimations];
        _Title.hidden = NO;
        _Ingrediants.hidden = NO;
        _Image.hidden = NO;
        _AddImage.hidden = NO;
}

- (IBAction)takePicture:(id)sender {

    UIImagePickerController *picker = [[UIImagePickerController alloc]init];
    picker.sourceType =  UIImagePickerControllerSourceTypePhotoLibrary;

    picker.allowsEditing = YES;
    picker.delegate = self;

    [self presentViewController:picker animated:YES completion:nil];



}

- (IBAction)resignKeyboard:(id)sender {

    [sender resignFirstResponder];
}
- (IBAction)saveButton:(id)sender {
    NSLog(@"HELLLOOO");



    UIAlertView * alert =[[UIAlertView alloc ] initWithTitle:@"Password" message:@"Enter a password to be able to edit this recipe in the future!" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles: nil];
    alert.alertViewStyle = UIAlertViewStyleSecureTextInput;
    [alert addButtonWithTitle:@"Enter"];
    [alert show];





   // uepassword = nil;

    _FinishedEditing.hidden = true;
}
- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
    if (buttonIndex == 1)
    {
        UITextField *password = [alertView textFieldAtIndex:0];
        //uepassword = password.text;

        //self.createdRecipe.title = _Title.text;
        //self.createdRecipe.ingrediants = _Ingrediants.text;
        //self.createdRecipe.method = _Recipe.text;
        //self.createdRecipe.img64 = _imagestring;
        //NSString *imageString;
        //if(_Image.image != nil)
        //{
          //  NSData *data = UIImagePNGRepresentation(_Image.image);
            //imageString = [data base64EncodedStringWithOptions:0];
        //}

       // [self.delegate userFinished:_Title.text :_Ingrediants.text :_Recipe.text :@"password" :imageString];

        [self performSegueWithIdentifier:@"back" sender:self];



    }
}

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{

    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
    self.Image.image = image;





    [self dismissViewControllerAnimated:YES completion:nil];
}



@end

AzureInteraction class

#import "AzureInteraction.h"
#import "Recipe.h"
#import "RecipeAzure.h"


@implementation AzureInteraction
{

}




-(id)initAzureInteraction
{
    self = [super init];

    if(self)
    {





        self.client = [client clientWithFilter:self];
         self.table = [_client tableWithName:@"Recipe"];

         self.busyCount = 0;





        return self;

    }
    return nil;
}



-(NSMutableArray*)getBreakfasts:(NSString*)pred
{
    NSLog(@"yeah its doing this but ");

    NSPredicate *bpred;
   if(pred == nil)
   {

     bpred = [NSPredicate predicateWithFormat:@"type == 'breakfast'"];
   }
   else{

        bpred = [NSPredicate predicateWithFormat:@"type == 'breakfast' AND title == %@",pred];
   }


    [_table readWithPredicate:bpred completion:^(NSArray *items, NSInteger totalCount, NSError *error) {


        _breakfasts = [items mutableCopy];


        [_delegate updateTableview];

    }];

    return _breakfasts;





}
-(NSMutableArray*)getLunches:(NSString*)pred
{
    NSLog(@"yeah its doing this but ");
    NSLog(@"%@",_recipes);

    NSPredicate *bpred;
    if(pred == nil)
    {
    bpred = [NSPredicate predicateWithFormat:@"type == 'lunch'"];
    }
    else{
        bpred = [NSPredicate predicateWithFormat:@"type == 'lunch' AND title == %@",pred];
    }


    [_table readWithPredicate:bpred completion:^(NSArray *items, NSInteger totalCount, NSError *error) {


        _lunches = [items mutableCopy];


        [_delegate updateTableview];

    }];

    return _lunches;


}
-(NSMutableArray*)getDinners:(NSString*)pred
{
    NSLog(@"yeah its doing this but ");
    NSLog(@"%@",_recipes);
    NSPredicate *bpred;
    if(pred == nil)
    {
     bpred = [NSPredicate predicateWithFormat:@"type == 'dinner'"];
    }
    else{
        bpred = [NSPredicate predicateWithFormat:@"type == 'dinner' AND title == %@",pred];
    }


    [_table readWithPredicate:bpred completion:^(NSArray *items, NSInteger totalCount, NSError *error) {


        _dinners = [items mutableCopy];


        [_delegate updateTableview];

    }];

    return _dinners;


}
-(void)updateTable
{






}
- (void)busy:(BOOL)busy
{
    // assumes always executes on UI thread
    if (busy)
    {
        if (self.busyCount == 0 && self.busyUpdate != nil)
        {
            self.busyUpdate(YES);
        }
        self.busyCount ++;
    }
    else
    {
        if (self.busyCount == 1 && self.busyUpdate != nil)
        {
            self.busyUpdate(FALSE);
        }
        self.busyCount--;
    }
}

- (void)handleRequest:(NSURLRequest *)request
                 next:(MSFilterNextBlock)next
             response:(MSFilterResponseBlock)response
{
    // A wrapped response block that decrements the busy counter
    MSFilterResponseBlock wrappedResponse = ^(NSHTTPURLResponse *innerResponse, NSData *data, NSError *error)
    {
        [self busy:NO];
        NSLog(@"OK");

        response(innerResponse, data, error);
    };

    // Increment the busy counter before sending the request
    [self busy:YES];
    NSLog(@"HMM");
    next(request, wrappedResponse);
}

-(RecipeAzure*)getBreakfastAtIndex:(NSIndexPath*)indexPath
{
    NSDictionary *d = [_breakfasts objectAtIndex:indexPath.row];

    RecipeAzure* t = [[RecipeAzure alloc] init];

    t.rid = [d valueForKey:@"id"];

    t.title = [d valueForKey:@"title"];
    t.ingrediants = [d valueForKey:@"ingrediants"];
    t.method = [d valueForKey:@"method"];
    t.type = [d valueForKey:@"type"];
    t.img64 = [d valueForKey:@"imageencoded"];
    t.password = [d valueForKey:@"password"];


    return t;
}
-(RecipeAzure*)getLunchAtIndex:(NSIndexPath*)indexPath
{
    NSDictionary *d = [_lunches objectAtIndex:indexPath.row];

    RecipeAzure* t = [[RecipeAzure alloc] init];
    t.rid = [d valueForKey:@"id"];
    t.title = [d valueForKey:@"title"];
    t.ingrediants = [d valueForKey:@"ingrediants"];
    t.method = [d valueForKey:@"method"];
    t.img64 = [ d valueForKey:@"imageencoded"];
    t.password = [d valueForKey:@"password"];

    return t;
}
-(RecipeAzure*)getDinnerAtIndex:(NSIndexPath*)indexPath
{
    NSDictionary *d = [_dinners objectAtIndex:indexPath.row];

    RecipeAzure* t = [[RecipeAzure alloc] init];
    t.rid = [d valueForKey:@"id"];
    t.title = [d valueForKey:@"title"];
    t.ingrediants = [d valueForKey:@"ingrediants"];
    t.method = [d valueForKey:@"method"];
    t.img64 = [ d valueForKey:@"imageencoded"];
    t.password = [d valueForKey:@"password"];

    return t;
}
-(NSInteger)breakfastCount
{
    NSLog(@"COUNTING");
    return [_breakfasts count];
}
-(NSInteger)lunchCount
{
    return [_lunches count];
}
-(NSInteger)dinnerCount
{
    return [_dinners count];
}
-(void)uploadRecipe:(RecipeAzure*)recipe
{
    NSDictionary *createdDictionary;
    if(recipe.img64 != nil)
    {
   createdDictionary = @{@"imageencoded": recipe.img64,@"ingrediants":recipe.ingrediants,
                               @"method":recipe.method,@"password":recipe.password,@"title":recipe.title,@"type":recipe.type};
   }
    else{
        createdDictionary = @{@"imageencoded": @"no image",@"ingrediants":recipe.ingrediants,@"method":recipe.method,@"password":recipe.password,@"title":recipe.title,@"type":recipe.type};
    }

    [_table insert:createdDictionary completion:^(NSDictionary *insertedItem, NSError *error) {
        if (error) {
            NSLog(@"Error: %@", error);
        } else {
            NSLog(@"Item inserted, id: %@", [insertedItem objectForKey:@"id"]);
        }
    }];

}

-(void)updateRecipe:(RecipeAzure*)r
{
    NSLog(@"BEFORE AN EXCEPTION");
    NSLog(r.rid);
  NSDictionary *createdDictionary = @{@"id":r.rid,@"imageencoded": r.img64,@"ingrediants":r.ingrediants,
                          @"method":r.method,@"password":r.password,@"title":r.title,@"type":r.type};
    [_table update:createdDictionary completion:^(NSDictionary *item, NSError *error) {
        if(error)
        {
            NSLog(@"%@",error);
        }
    }];
}




@end

The CustomCell class doesn't really have any logic within it.. So here's the .h file instead!

#import <UIKit/UIKit.h>

@interface CustomCell : UITableViewCell
@property (weak, nonatomic) IBOutlet UILabel *RecipeTitle;
@property (weak, nonatomic) IBOutlet UILabel *IngrediantsLabel;
@property (weak, nonatomic) IBOutlet UIImageView *RecipeImage;

@end

Answer 1

Not sure what you're doing here:

// A wrapped response block that decrements the busy counter
MSFilterResponseBlock wrappedResponse = ^(NSHTTPURLResponse *innerResponse, NSData *data, NSError *error)
{
    [self busy:NO];
    NSLog(@"OK");

    response(innerResponse, data, error);
};

But use the weakSelf pattern:

Before the block: __weak AzureInteraction* weakSelf = self;

And then in the block: [weakSelf busy:NO]

Blocks that invoke self will retain self unless the reference is explicitly weak.

Also, your use of _delegate in a block is equally scary. Though that block likely completes more synchronously than this one.

I'm scrutinizing your blocks because of the stack trace, but it could be another that you don't show here given that it's something about pixel rendition. Regardless, you need to be aware that these blocks you are invoking will retain pointers to the objects within them.

Answer 2

I can't see the problem but I suggest doing a bunch of code cleanup. You have a whole lot of weird stuff going on like this:

NSPredicate *bpred;
if(pred == nil)
{
  bpred = [NSPredicate predicateWithFormat:@"type == 'lunch'"];
}
else{
  bpred = [NSPredicate predicateWithFormat:@"type == 'lunch' AND title == %@",pred];
}

How can it ever not be nil?

And this, which does nothing at all:

self.ai.busyUpdate = ^(BOOL busy)
{
    if (busy)
    {

    } else
    {

    }
};

I would commit to version control (you're using version control right?) and delete/fix all of that stuff. Then see if the leak is still there.

If the leak is still there, perhaps start deleting big chunks of code just to find out where the leak is. Then once you've narrowed the problem down you should be able to find the issue and restore all your deleted code from version control.

It's extremely unlikely to be a bug in iOS. The NSString class was created in the early 1980's and hasn't changed much since, any bugs were fixed a long long time ago.