I have a couple of classes which functions are execute SQL statements against a WEB service in order to get or set data in the database.
Works fine, but the problem is when I’m testing in instruments/leaks the 90% of the leaks are because these classes.
Could you tell me what I’m loosing?
Thanks.
Here is the code:
Where the data is stored:
.h
@interface iSQLResult : NSObject {
NSMutableArray *Records;
}
@property (nonatomic, assign) int CountX;
@property (nonatomic, assign) int CountY;
@property (nonatomic, retain) NSMutableArray *Columns;
@property (nonatomic, retain) NSMutableArray *Records;
@property (nonatomic, retain) NSMutableArray *FieldsNames;
@property (nonatomic, assign) int ErrorCode;
@property (nonatomic, retain) NSString *ErrorDescription;
-(void)addField:(NSString*)fieldName;
-(void)addRecord:(NSMutableArray*)items;
-(NSMutableArray *)getRecord:(int)y;
-(NSString*)getValue:(int) x posY:(int) y;
-(NSString*)getValueByName:(NSString *) colName posY:(int) y;
-(void)setValueByName:(NSString *) colName posY:(int) y value:(NSString *)value;
-(id) copyWithZone: (NSZone *) zone;
@end
.m
#import "iSQLResult.h"
#import <stdarg.h>
@implementation iSQLResult
@synthesize CountX;
@synthesize CountY;
@synthesize Columns;
@synthesize Records;
@synthesize FieldsNames;
@synthesize ErrorCode;
@synthesize ErrorDescription;
-(id)init
{
self = [super init];
if (self)
{
self.CountX =0;
self.CountY =0;
self.ErrorCode = 0;
self.ErrorDescription = @"";
self.FieldsNames = [NSMutableArray array];
self.Columns = [NSMutableArray array];
self.Records = [NSMutableArray array];
}
return self;
}
-(void)removeRecord:(int)index
{
[self.Records removeObjectAtIndex:index];
self.CountY = self.CountY - 1;
}
-(void)addField:(NSString*)fieldName
{
[self.FieldsNames addObject:[NSString stringWithFormat:@"%@", fieldName]];
self.CountX = self.CountX +1;
}
-(void)addRecord:(NSMutableArray*)items
{
[self.Records addObject:items];
self.CountY = self.CountY +1;
}
-(NSMutableArray *)getRecord:(int)y
{
return [Records objectAtIndex:y];
}
-(NSString *)getValue:(int) x posY:(int)y
{
return [[NSString stringWithFormat:@"%@", [[Records objectAtIndex:y] objectAtIndex:x]] copy];
}
-(NSString*)getValueByName:(NSString *) colName posY:(int) y
{
int a=0;
for (a=0;a<CountX;a++)
{
if ([[colName uppercaseString] isEqualToString:[[FieldsNames objectAtIndex:a] uppercaseString]])
{
return [[NSString stringWithFormat:@"%@", [[Records objectAtIndex:y] objectAtIndex:a]] copy];
}
}
return @"";
}
-(void)setValueByName:(NSString *) colName posY:(int) y value:(NSString *)value
{
int a=0;
for (a=0;a<CountX;a++)
{
if ([[colName uppercaseString] isEqualToString:[[FieldsNames objectAtIndex:a] uppercaseString]])
{
[[Records objectAtIndex:y] replaceObjectAtIndex:a withObject:value];
}
}
}
-(void)dealloc
{
[Columns release];
[Records release];
[FieldsNames release];
[ErrorDescription release];
[super dealloc];
}
-(id) copyWithZone: (NSZone *) zone
{
iSQLResult *SQLRCopy = [[iSQLResult allocWithZone: zone] init];
[SQLRCopy setCountX:self.CountX];
[SQLRCopy setCountY:self.CountY];
[SQLRCopy setRecords:[self.Records mutableCopyWithZone:zone]];
[SQLRCopy setColumns:[self.Columns mutableCopyWithZone:zone]];
[SQLRCopy setFieldsNames:[self.FieldsNames mutableCopyWithZone:zone]];
[SQLRCopy setErrorCode:self.ErrorCode];
[SQLRCopy setErrorDescription:[self.ErrorDescription copyWithZone:zone]];
return SQLRCopy;
}
@end
The class who ask for the data to the web service comunication class and gets a xml structure:
.h
#import <Foundation/Foundation.h>
#import "iSQLResult.h"
#import "IM2_WebServiceComm.h"
@interface iSQL : NSObject <NSXMLParserDelegate> {
iSQLResult *SQLR;
IM2_WebServiceComm * WSC;
NSXMLParser *xmlParser;
BOOL Found;
BOOL FieldsReaded;
BOOL loadFieldsNow;
BOOL loadErrNumNow;
BOOL loadErrDesNow;
NSString *chunksString;
NSMutableArray *tempRecord;
}
@property (nonatomic, retain) NSString *URLConnection;
-(void)SQLReader:(NSString*)SQLString;
-(void)SQLExec:(NSString*)SQLString;
-(void)setURLConnection:(NSString *) WebSURL;
-(iSQLResult*) getSQLR;
-(void) parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName;
-(void) parser:(NSXMLParser *) parser foundCharacters:(NSString *)string;
-(void) parser:(NSXMLParser *) parser didStartElement:(NSString *) elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *) qName attributes:(NSDictionary *) attributeDict;
@end
.m
#import "iSQL.h"
@implementation iSQL
@synthesize URLConnection;
- (iSQLResult*)getSQLR
{
return [SQLR copy];
}
-(void)SQLExec:(NSString*)SQLString
{
FieldsReaded = NO;
Found = NO;
loadFieldsNow = NO;
if (SQLR)
{
[SQLR release];
SQLR = nil;
}
SQLR = [[iSQLResult alloc] init];
WSC = [[IM2_WebServiceComm alloc] init];
[WSC setURL:URLConnection];
NSString *theXML = [WSC callMethod:@"ExecNonQuery" sendInstruction:SQLString];
@try
{
xmlParser = [[NSXMLParser alloc] initWithData:[theXML dataUsingEncoding:NSUTF8StringEncoding]];
[xmlParser setDelegate: self];
[xmlParser setShouldResolveExternalEntities:NO];
if(![xmlParser parse])
{
NSLog(@"ERROR PARSING");
}
[xmlParser release];
}
@catch(NSException * ex)
{
NSLog(@"%@",[[ex reason] UTF8String]);
}
[WSC release];
}
-(void)SQLReader:(NSString*)SQLString
{
FieldsReaded = NO;
Found = NO;
loadFieldsNow = NO;
if (SQLR)
{
[SQLR release];
SQLR = nil;
}
SQLR = [[iSQLResult alloc] init];
WSC = [[IM2_WebServiceComm alloc] init];
[WSC setURL:URLConnection];
NSString *theXML = [WSC callMethod:@"ExecSQL" sendInstruction:SQLString];
@try
{
xmlParser = [[NSXMLParser alloc] initWithData:[theXML dataUsingEncoding:NSUTF8StringEncoding]];
[xmlParser setDelegate: self];
[xmlParser setShouldResolveExternalEntities:NO];
if(![xmlParser parse])
{
NSLog(@"ERROR PARSING");
}
[xmlParser release];
}
@catch(NSException * ex)
{
NSLog([NSString stringWithFormat:@"%@",[[ex reason] UTF8String]]);
}
[WSC release];
}
-(iSQLResult *)getSingleSQLR:(iSQLResult *)SQLSource usingRow:(int)y
{
iSQLResult *SQLRAux = [[[iSQLResult alloc]init]retain];
[SQLRAux setCountX:SQLSource.CountX];
[SQLRAux addRecord:[SQLSource getRecord:y]];
[SQLRAux setFieldsNames:SQLSource.FieldsNames];
return SQLRAux;
}
-(void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError{
NSLog(@"Error on XML Parse: %@", [parseError localizedDescription] );
}
//#pragma XML Parser Delegate Methods
-(void) parser:(NSXMLParser *) parser didStartElement:(NSString *) elementName namespaceURI:(NSString *) namespaceURI qualifiedName:(NSString *) qName attributes:(NSDictionary *) attributeDict
{
if (!chunksString)
{
chunksString = [[NSString alloc] init];
}
chunksString = @"";
if ([elementName isEqualToString:@"ErrCode"])
{
loadErrNumNow = YES;
}
if ([elementName isEqualToString:@"ErrDesc"])
{
loadErrDesNow = YES;
}
if ([elementName isEqualToString:@"Table"])
{
Found = YES;
loadFieldsNow = NO;
tempRecord = [[NSMutableArray alloc] init];
}
if (Found && ![elementName isEqualToString:@"Table"])
{
loadFieldsNow = YES;
if (!FieldsReaded)
{
[SQLR addField:elementName];
}
}
}
-(void) parser:(NSXMLParser *) parser foundCharacters:(NSString *)string
{
chunksString = [chunksString stringByAppendingString:string];
}
-(void) parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{
NSString * finalString;
finalString = [NSString stringWithFormat:@"%@",chunksString];
if (loadErrNumNow)
{
[SQLR setErrorCode:[finalString intValue] ];
loadErrNumNow = NO;
}
if (loadErrDesNow)
{
[SQLR setErrorDescription:finalString];
loadErrDesNow = NO;
}
if (Found)
{
if (loadFieldsNow)
{
[tempRecord addObject:finalString];
}
}
if ([elementName isEqualToString:@"Table"])
{
[SQLR addRecord:tempRecord];
[tempRecord release];
Found = NO;
FieldsReaded = YES;
loadFieldsNow = NO;
}
}
-(void)dealloc
{
if (SQLR)
{
[SQLR release];
SQLR = nil;
}
[URLConnection release];
[super dealloc];
}
@end
This is an absolutely buggy class because the leaks, every access is a leak 🙁
Any help please?
Here are some things I notice:
-[iSQLResult copyWithZone:]
You’re sending the result of mutableCopyWithZone: (which returns a retained object) to the setters, which retain the object again. One way to fix it is to autorelease the copy:
-[iSQL SQLExec:] and -[iSQL SQLReader:]
The ivars WSC and xmlPareser are alloced then released but not set to nil. This isn’t a leak, but you’re keeping a reference to a released object. If you dereference that, you’ll crash.
-[iSQL getSingleSQLR:usingRow:]
Did you mean autorelease instead of retain there? (And if you did, shouldn’t you also autorelease the return in getSQLR, for consistency?)
-[iSQL parser:didStartElement:namespaceURI:qualifiedName:attributes:]
chunksString is alloced (+1 retain), but later in parser:foundCharacters: you’re losing the reference (i.e., leaking the string) and replacing it with an autoreleased string.
That’s all I notice off hand. It sounds like you’re leaking more than just those objects, so I’m guessing you’re leaking iSQL and/or iSQLResult objects, too. Remember, when you leak an object, you also leak everything those objects hold a reference to. Even if these classes were leak-free, if the code that’s instantiating the classes isn’t properly releasing the objects you’ll see all the members in these classes leak, too. When fixing leaks, always look for “top-level” objects first.