why there is a memory leak in this method?

• Leo why there is a memory leak in this method? Nov 24 2006, 07:21
  Hi all:
  
  I have a simple method:
  
  - (NSString *)hTagString:(NSString *)source{
  NSString *hTag=nil;
  
  NSRange startRange=[source rangeOfString:@"<h1"
  options:NSCaseInsensitiveSearch];
  
  if(startRange.length!=0){
  NSRange endRange=[source rangeOfString:@"</h1>"
  options:NSCaseInsensitiveSearch];
  NSRange tmpRange=[source rangeOfString:@">" options:NSCaseInsensitiveSearch
  range:NSMakeRange(startRange.location+startRange.length,endRange.location-startRange.location-startRange.length)];
  
  int start=tmpRange.location+tmpRange.length;
  
  int len=endRange.location-tmpRange.location-tmpRange.length;
  
  NSString *tmpTag=[source substringWithRange:NSMakeRange(start,len)];
  
  NSAttributedString *test=[[[NSAttributedString alloc]
  initWithHTML:[tmpTag dataUsingEncoding:[tmpTag fastestEncoding]]
  documentAttributes:nil] autorelease];
  hTag=[test string];
  
  }
  
  return hTag;
  
  }
  
  when i test it with MallocDebug and it displays there is a memory leak
  in [NSAttributedString alloc] initWithHTML, but i have already
  autorealease it, why it still has a leak? should i use NSAutoreleasePool?
  
  Does anybody can help me, thank you.
  
  Leo
• Matt Neuburg Re: why there is a memory leak in this method? Nov 24 2006, 17:24
  On Fri, 24 Nov 2006 14:21:46 +0800, Leo <amokok...> said:
  
  

  > NSAttributedString *test=[[[NSAttributedString alloc]
  > initWithHTML:[tmpTag dataUsingEncoding:[tmpTag fastestEncoding]]
  > documentAttributes:nil] autorelease];
  > hTag=[test string];
  >
  > }
  >
  > return hTag;
  >
  > }
  >
  > when i test it with MallocDebug and it displays there is a memory leak
  > in [NSAttributedString alloc] initWithHTML, but i have already
  > autorealease it, why it still has a leak? should i use NSAutoreleasePool?
  

  
  You never know for sure what autorelease will return, so my first piece of
  advice would be to write it like this:
  
  NSAttributedString *test=
    [[NSAttributedString alloc] initWithHTML:
    [tmpTag dataUsingEncoding:[tmpTag fastestEncoding]]
    documentAttributes:nil];
  [test autorelease];
  
  Second, are you planning to modify the NSAttributedString's string directly?
  If not - that is, if you just want to see it - consider making a copy. In
  that case you can just release the original attributed string.
  
  NSAttributedString *test =
    [[NSAttributedString alloc] initWithHTML:
    [tmpTag dataUsingEncoding:[tmpTag fastestEncoding]]
    documentAttributes:nil];
  hTag = [[test string] copy];
  [test release];
  [hTag autorelease];
  
  See if any of that helps. m.
  --
  matt neuburg, phd = <matt...>, <http://www.tidbits.com/matt/>
  A fool + a tool + an autorelease pool = cool!
  AppleScript: the Definitive Guide - Second Edition!
  <http://www.amazon.com/gp/product/0596102119>
• Philip Q Re: Re: why there is a memory leak in this method? Nov 25 2006, 06:39
  On 25/11/06, Matt Neuburg <matt...> wrote:
  

  > You never know for sure what autorelease will return, so my first piece of
  > advice would be to write it like this:
  

  
  The docs state (for -autorelease):
  Return Value
  self.
  
  -Phil
• Scott Stevenson Re: why there is a memory leak in this method? Nov 25 2006, 07:29
  On Nov 23, 2006, at 10:21 PM, Leo wrote:
  
  

  > I have a simple method:
  >
  > - (NSString *)hTagString:(NSString *)source{
  > NSString *hTag=nil;
  

  
  Your code looks correct. I don't know why it's leaking, but consider
  using just 'release' at the end of the method. You don't always have
  to use autorelease, and it's actually more characters to type.
  
  Also, since you're doing HTML parsing, make sure you're not
  replicating code that already exists in WebKit. There's some
  fantastic stuff for dealing with web page source. Check out the
  classes declared in WebKit's DOMCore.h and DOMHTML.h. Particularly
  things like DOMHTMLDocument's getElementsByName.
  
  [ Side note for everyone else: I can't find documentation for the DOM
  classes anywhere -- only the category additions. It seems strange
  that it wouldn't exist. Is it hiding somewhere? Googling for
  "site:developer.apple.com DOMHTMLDocument" returns zero results. ]
  
      - Scott
• Chris Ridd Re: why there is a memory leak in this method? Nov 25 2006, 07:51
  On 25/11/06 6:29, Scott Stevenson <scott...> wrote:
  
  

  > [ Side note for everyone else: I can't find documentation for the DOM
  > classes anywhere -- only the category additions. It seems strange
  > that it wouldn't exist. Is it hiding somewhere? Googling for
  > "site:developer.apple.com DOMHTMLDocument" returns zero results. ]
  

  
  All there is is a link to the IDL files at W3C (especially useful when
  you're offline), and the assumption that you can mentally parse them into
  Objective C :-(
  
  Gah. I end up opening DOM*.h.
  
  Cheers,
  
  Chris
• Scott Stevenson Re: why there is a memory leak in this method? Nov 25 2006, 08:46
  On Nov 24, 2006, at 10:51 PM, Chris Ridd wrote:
  
  

  >> [ Side note for everyone else: I can't find documentation for the DOM
  >> classes anywhere -- only the category additions. It seems strange
  >> that it wouldn't exist. Is it hiding somewhere? Googling for
  >> "site:developer.apple.com DOMHTMLDocument" returns zero results. ]
  >
  > All there is is a link to the IDL files at W3C (especially useful when
  > you're offline), and the assumption that you can mentally parse
  > them into
  > Objective C :-(
  >
  > Gah. I end up opening DOM*.h.
  

  
  I filed a bug. Maybe anybody else who would like some class
  references could do the same.
  
      - Scott