I have recently inherited a large project using an sqlite3 database and currently I am muscling through a significant amount of memory leaks scattered throughout. A couple of the leaks have me confused and demoralised after not being able to solve them. This loop within a method leaks an awful amount of bytes but appears to be so simplistic I simply don't know how to change it to prevent the leak.
...
while ((ret=sqlite3_step(selStmt))==SQLITE_ROW)
{
GraphData *item = [GraphData alloc];
item.key = sqlite3_column_int(selStmt, 0);
item.value = [NSString stringWithUTF8String:(char *)sqlite3_column_text(selStmt,1)];
[newData addObject:item];
[item release], item = nil;
}
...
#interface GraphData : NSObject{
NSInteger key;
NSString *value;
}
#property (nonatomic, readwrite) NSInteger key;
#property (nonatomic, retain) NSString *value;
-(id)initWithPrimaryKey:(NSInteger) xid;
-(id)initWithName:(NSString *)n key:(NSInteger)i;
#end
#import "GraphData.h"
#implementation GraphData
#synthesize key,value;
-(id)initWithPrimaryKey:(NSInteger) xid{
self.key = xid;
self.value = #"";
return self;
}
-(id)initWithName:(NSString *)n key:(NSInteger)i{
self.key = 0;
self.value = n;
return self;
}
#end
Almost all the leaks within this datasource class come from this loop.
I'm hoping this is something trivial that my inexperience has overlooked.
Thanks for taking the time to look at my question.
There's no dealloc in your GraphData class.
- (void)dealloc {
[value release];
[super dealloc];
}
(I assume you're not using ARC because you have release in your first code snippet. I really recommend converting to ARC - this kind of leak vanishes.)
Related
I have declared NSString with some string value in ViewdidLoad like..
int i=1;
strval=[NSString stringWithFormat:#"%03d",i];
strval=[NSString stringWithFormat:#"S%#",strval];
NSLog(#"Value %#",strval);
it gives correct result as S001, but when i print this same in IBAction like,
- (IBAction)stringvalue:(id)sender {
NSLog(#"Value %#",strval);
}
it gives unknown values each time.Sometimes it throws EXEC_BAD_ACCESS error.
Please help me..
Try something like this
in .h
#property (nonatomic, strong) NSString *strval;
in .m
#synthesize strval = _strval
- (void)viewDidLoad
{
int i = 4;
// ARC
_strval = [NSString stringWithFormat:#"hello %d", i];
// None ARC
// strcal = [[NSString alloc] initwithFormat:#"hello %d",i];
NSLog(#"%#", _strval);
// Prints "hello 4" in console (TESTED)
}
- (IBAction)buttonPress:(id)sender
{
NSLog(#"%#", _strval);
// Prints "hello 4" in console (TESTED)
}
using ARC. This has been tested and works the way the question has been asked.
Looks like you aren't using ARC, so the string is being released the next time the autorelease pool drains. You need to explicitly retain it in viewDidLoad and explicitly release it in your overwridden dealloc method:
- (void)viewDidLoad
{
...
strval = [[NSString stringWithFormat:#"%03d", i] retain];
....
}
- (void)dealloc
{
[strval release];
...
[super dealloc];
}
(I am assuming you've actually declared strval as an instance method).
in .h
#property (nonatomic, strong) NSString *strval;
in .m
#synthesize strval = _strval
- (void)viewDidLoad
{
...
self.strval = [NSString stringWithFormat:#"%03d", i];
....
}
- (void)dealloc
{
self.strval = nil;
...
[super dealloc];
}
This one works either, with ARC and without.
Just one addition: With ARC the statement [super dealloc]; must be omitted.
Hello I'm new to iPhone development.
I try to add move data from NSDictionary to data member of calls that i created.
When i "setWeightMeasure" nothing happened.
any suggestions?
the code that don't work:
NSDictionary *responseBodyProfile = [responseBody objectFromJSONString];
NSLog(#"%#",responseBodyProfile);
// the output is :
"{ "profile": {"goal_weight_kg": "77.0000", "height_cm": "179.00",
"height_measure": "Cm", "last_weight_date_int": "15452",
"last_weight_kg": "99.0000", "weight_measure": "Kg" }}""
[responseBody release];
if (responseBodyProfile != nil ){
NSDictionary *profile =[responseBodyProfile valueForKey:#"profile"];
NSLog(#"%#\n",[profile objectForKey:#"weight_measure"]);// Output : "kg"
[self.myUser setWeightMeasure:[profile objectForKey:#"weight_measure"]];
NSLog(#"%#", [self.myUser WeightMeasure]); // Output : "(null)"
}
the H file properyty:
#property (nonatomic, retain) UserData* myUser;
UserData.h:
#import <Foundation/Foundation.h>
#interface UserData : NSObject{
NSString* Weight;
NSString* Height;
NSString* GolWeight;
NSString* WeightMeasure;
}
#property (nonatomic, retain) NSString* Weight;
#property (nonatomic, retain) NSString* Height;
#property (nonatomic, retain) NSString* GolWeight;
#property (nonatomic, retain) NSString* WeightMeasure;
#end
UserData.m
#import "UserData.h"
#implementation UserData
#synthesize Weight, Height, GolWeight, WeightMeasure;
-(id)init{
self.Weight = #"0";
self.Height = #"0";
self.GolWeight = #"0";
self.WeightMeasure = #"0";
return self;
}
-(void)dealloc{
[Weight release];
[Height release];
[GolWeight release];
[WeightMeasure release];
[super dealloc];
}
#end
Use valueForKey instead of objectForKey in this line:
[self.myUser setWeightMeasure:[profile objectForKey:#"weight_measure"]];
like this:
[self.myUser setWeightMeasure:[profile valueForKey:#"weight_measure"]];
You might also want to use, since the values could be read as NSNumbers
[self.myUser setWeightMeasure:[[profile valueForKey:#"weight_measure"] stringValue]];
And why do you use strings instead of floats? Wouldn't that make your life easier when you'd need to perform some comparisons?
Also check if you have allocated memory for "myUser", that might be the case as well.
As Eugene mentioned, you should use valueForKey instead of objectForKey
The other thing is you might wanna use property and dot notation whenever you reference your object members, as Apple recommend. It is generally good for you to manage memory.
The previous answer about not initialize your string members in your -init() was totally wrong, if that cause some confusion, I do apologize for it.
I've made a container class to store a single tweet. Its initialized by passing in a dictionary object which is a single tweet.
I then store an array of these 'tweets' which I process through to display in a table.
The project is now finished and I am reviewing everything at the moment and I was wondering is there a better way to do this in the future. Is the memory handled correctly. I declare the string member vars with 'copy' and later in the dealloc I use a 'release' rather than just setting them to 'nil'.
Is my init ok or could that be improved?
Tweet.h
#import
#interface Tweet : NSObject
{
NSString * _userName;
NSString * _tweetText;
NSString * _tweetURL;
}
#property (nonatomic, copy) NSString * userName;
#property (nonatomic, copy) NSString * tweetText;
#property (nonatomic, copy) NSString * tweetURL;
- (id) initWithDict:(NSDictionary *)productsDictionary;
#end
Tweet.m
#implementation Tweet
#synthesize userName = _userName;
#synthesize tweetText = _tweetText;
#synthesize tweetURL = _tweetURL;
- (id) initWithDict:(NSDictionary *)productsDictionary
{
NSDictionary *aDict = [productsDictionary objectForKey:#"user"];
self.userName = [aDict objectForKey:#"screen_name"];
self.tweetText = [productsDictionary objectForKey:#"text"];
NSRange match;
match = [self.tweetText rangeOfString: #"http://"];
if (match.location != NSNotFound)
{
NSString *substring = [self.tweetText substringFromIndex:match.location];
NSRange match2 = [substring rangeOfString: #" "];
if (match2.location == NSNotFound)
{
self.tweetURL = substring;
}
else
{
self.tweetURL = [substring substringToIndex:match2.location];
}
}
else
{
self.tweetURL = nil;
}
return self;
}
-(void) dealloc
{
[self.tweetText release];
[self.tweetURL release];
[self.userName release];
[super dealloc];
}
#end
Many Thanks,
Code
At first sight, I see no inherent flaws here. That looks fine. I would prefer to do:
-(void) dealloc
{
[_tweetText release];
[_tweetURL release];
[_userName release];
[super dealloc];
}
But what you do is good as well.
I create a NSMutableString called mutableScoreHolder outside my do-while loop.
I alloc it, 'copy' it into an other object called a 'Match' that contains a NSString.
When I build and analyze the code it reports a potential memory leak of my mutableScoreHolder.
NSString * scoreHolder;
NSMutableString * mutableScoreHolder;
count = 1;
numMatchCounter = 0;
int startOfScoreIndex = 0;
int endOfScoreIndex = 0;
int numberOfGoals=0;
do
{
match = [substring rangeOfString: #"points_bg"];
if (match.location == NSNotFound)
{
break;
}
if ((match.location + match.length) > ([substring length]))
{
break;
}
substring = [substring substringFromIndex:(match.location + match.length)];
match2 = [substring rangeOfString: #">"];
startOfScoreIndex = match2.location+1;
match2 = [substring rangeOfString: #"<"];
endOfScoreIndex = match2.location;
if ((count % 2) == 1)
{
scoreHolder = [substring substringWithRange:NSMakeRange(startOfScoreIndex, (endOfScoreIndex-startOfScoreIndex))];
mutableScoreHolder = [[NSMutableString alloc] initWithString:scoreHolder];
numberOfGoals += [scoreHolder intValue];
}
else
{
Match *aMatch = [theMatchScoresArray objectAtIndex:(numMatchCounter)];
numberOfGoals += [[substring substringWithRange:NSMakeRange(startOfScoreIndex, (endOfScoreIndex-startOfScoreIndex))] intValue];
[scoreHolder stringByAppendingString:#" - "];
[mutableScoreHolder appendString:#" - "];
[scoreHolder stringByAppendingString:[substring substringWithRange:NSMakeRange(startOfScoreIndex, (endOfScoreIndex-startOfScoreIndex))]];
[mutableScoreHolder appendString:[substring substringWithRange:NSMakeRange(startOfScoreIndex, (endOfScoreIndex-startOfScoreIndex))]];
aMatch.theScore = [mutableScoreHolder copy];
aMatch.matchGoalCount = numberOfGoals;
numMatchCounter++;
numberOfGoals=0;
}
count++;
}
while ( match.length != 0 );
Here is my Match Object Class.
#interface Match : NSObject
{
NSString *teamName1;
NSString *teamName2;
NSString *theScore;
int matchGoalCount;
NSMutableArray *scorersArray;
NSMutableArray *scorerOrderArray;
NSString *matchStatus;
NSString *matchDate;
bool matchNotStarted;
}
#property(nonatomic) int matchGoalCount;
#property(nonatomic) bool matchNotStarted;
#property(nonatomic, retain) NSString *teamName1;
#property(nonatomic, retain) NSString *teamName2;
#property(nonatomic, retain) NSString *theScore;
#property(nonatomic, retain) NSString *matchStatus;
#property(nonatomic, retain) NSString *matchDate;
#property(nonatomic, retain) NSMutableArray *scorersArray;
#property(nonatomic, retain) NSMutableArray *scorerOrderArray;
-(id)init;
#end
#import "Match.h"
#implementation Match
#synthesize teamName1;
#synthesize teamName2;
#synthesize theScore;
#synthesize scorersArray;
#synthesize matchDate;
#synthesize matchStatus;
#synthesize matchGoalCount;
#synthesize scorerOrderArray;
#synthesize matchNotStarted;
-(id)init
{
//NSLog(#"****** MATCH INIT ******");
self = [super init];
scorersArray =[[NSMutableArray alloc] init];
scorerOrderArray =[[NSMutableArray alloc] init];
return self;
}
-(void) dealloc
{
[scorersArray release];
[scorerOrderArray release];
[teamName1 release];
[teamName2 release];
[theScore release];
[matchStatus release];
[matchDate release];
[scorersArray release];
[scorerOrderArray release];
[super dealloc];
}
#end
I do find there there is a string leaked when i run instruments checking for leaks. So I think this 'potential leak' might be the leak I see.
Because the scores has a retain
#property(nonatomic, retain) NSString *theScore;
And there is a string copied into it
aMatch.theScore = [mutableScoreHolder copy];
Could that give a retain count of 2? And so then leak?
Sorry for the complicated question! Has my head spinning trying to get my head around it.
Thanks
-Code
You're definitely leaking here, for 2 separate reasons.
The first is you're alloc/init'ing an NSMutableString and stuffing it into mutableScoreHolder. This is a local variable, and as soon as this value goes out of scope (or gets replaced the next time a new array is created) the old value is leaked. This should be an autoreleased value instead, as in [NSMutableString stringWithString:scoreHolder].
The second is you're copying the string and stuffing the resulting value into a property. What you should do is redeclare that property as copy
#property(nonatomic, copy) NSString *theScore;
and then just assign mutableScoreHolder to that property directly
aMatch.theScore = mutableScoreHolder
With your existing code, you copy the array, and then the property retains it. With this change, the property copies it directly, and no extra retains are used.
Note, in general it's a good idea to declare properties with supported types as copy. This includes things like NSString, NSArray, NSDictionary, etc. If you're assigning an already-immutable object to the property, the copy falls back to retain instead and there's no performance hit. But in situations like yours where you're assigning mutable objects, it will copy it as appropriate and keep an immutable snapshot in the property.
And there is a string copied into it
aMatch.theScore = [mutableScoreHolder copy];
Could that
give a retain count of 2? And so then
leak?
exactly. You could change the property of theScore from retain to copy to fix this. THen you can use aMatch.theScore = mutableScoreHolder;
and there is (at least) one other leak:
mutableScoreHolder = [[NSMutableString alloc] initWithString:scoreHolder];
this gets never released.
This is really twisting my mind… I'm trying to access an NSMutableArray in an IBAction which I defined in viewDidLoad. Unfortunately I keep getting a EXC_BAD_ACCESS.
I'm new to all this so I'd really appreciate some insight in what I'm doing wrong.
Below find the corresponding code excerpts.
CounterViewController.h:
#interface CounterViewController : UIViewController{
NSMutableArray *countHistoryArray;
}
#property(nonatomic, retain) NSMutableArray *countHistoryArray;
CounterViewController.m:
#implementation CounterViewController
#synthesize countHistoryArray;
- (void)viewDidLoad {
[super viewDidLoad];
//Fill array with some dummy data
self.countHistoryArray = [[NSMutableArray alloc] init];
NSDate *now = [[[NSDate alloc] init] autorelease];
CurrentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
[self.countHistoryArray addObject: historicCount];
//Do some logging - everything is working fine here!
NSLog(#"%#", [self.countHistoryArray description]);
}
//Later on we click on a button and want to use the array
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Thanks a lot!
Manuel
EDIT Additional code as asked for by #jamapag
CurrentCount.h
#import <Foundation/Foundation.h>
#interface CurrentCount : NSObject {
NSNumber *counterLevel;
NSString *description;
NSDate *dateAndTime;
}
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime;
#property(nonatomic, copy) NSNumber *counterLevel;
#property(nonatomic, copy) NSString *description;
#property(nonatomic, copy) NSDate *dateAndTime;
#end
CurrentCount.m
#import "CurrentCount.h"
#implementation CurrentCount
#synthesize counterLevel;
#synthesize description;
#synthesize dateAndTime;
- (id)initWithCount:(NSNumber *)newCounterLevel description:(NSString *)newDescription dateAndTime:(NSDate *)newDateAndTime{
self = [super init];
if(nil != self){
self.counterLevel = newCounterLevel;
self.description = newDescription;
self.dateAndTime = newDateAndTime;
}
return self;
}
-(void) dealloc{
self.counterLevel = nil;
self.description = nil;
self.dateAndTime = nil;
[super dealloc];
}
#end
Are you sure that your code actually looks like this?
- (IBAction)doSomeStuff {
//Let's look at the array again - and now it crashes with EXC_BAD_ACCESS
NSLog(#"%#", [self.countHistoryArray description]);
}
Your question title says "NSMutableArray count causes EXC_BAD_ACCESS" - if that line of code actually says NSLog(#"%#", [self.countHistoryArray count]);, you'll almost certainly get a crash, since NSLog will attempt to treat a primitive type (the type returned by -[NSArray count]) as an object. In order to use -[NSArray count] in NSLog, use %u instead of %#:
- (IBAction)doSomeStuff {
// This time it should work!
NSLog(#"Array Count = %u", [self.countHistoryArray count]);
}
Remove autorelease from:
currentCount *historicCount = [[[CurrentCount alloc]
initWithCount:[NSNumber numberWithInteger:22]
description:#"Testcount"
dateAndTime:now] autorelease];
It looks like you are accidentally releasing countHistoryArray somewhere. Try removing all calls to it except for those two you showed. Additionally you can try enabling zombies to debug the problem.
Oh and by the way you probably don't really want a public NSMutableArray property and if you do you probably want it to be copy, not retain. Otherwise incapsulation kinda goes down the drain.
I know this question has already been solved and accepted but its for others who are or will face this issue.
I was facing the same issue, I tried all solutions but no solution worked for me. The project I am working on is NON-ARC.
I tried and made a simple change in property
Previously my property for NSMUTABLEARRAY was
#property (nonatomic, assign) NSMutableArray * dataArray;
I changed it to:
#property (nonatomic, retain) NSMutableArray * dataArray;
Changed it from ASSIGN to RETAIN
And it solved my problem