snippet107.d

[WendleC]

Line 254 in file dwt/widgets/Button.d

NSAttributedString createString() {
NSAttributedString attribStr = createString(text, null, foreground, style, true, true);
attribStr.autorelease();
return attribStr;
}

attribStr.autorelease(); causes the crash. If commented out, snippet won't crash. Problem (probably): attribStr is freed before it is returned. In Objective-C this is normally avoided by

return [attribStr autorelease]; // in the return statement

Note: Check how many other snippets depend on Buttons!

[jacob-carlborg]

I guess it would be possible to do return attribStr.autorelease(); but do you think that would make any difference?

[WendleC]

return attribStr.autorelease();

Didn't work. I got the following error when compiling:

./dwt/widgets/Button.d(255): Error: cannot implicitly convert expression (attribStr.autorelease()) of type dwt.internal.cocoa.NSObject.NSObject to dwt.internal.cocoa.NSAttributedString.NSAttributedString

[jacob-carlborg]

You would need to explicitly cast it to the correct type:

return cast(NSAttributedString) attribStr.autorelease();

[jacob-carlborg]

If most of the snippets depend on Button then I guess there's no point in trying those snippets until this issue is solved.

[WendleC]

Tried the autorelease in return statement with cast as you suggested. Still crashes.

It is not so only Button. It is createString() which is used by many widgets (Labels, Buttons, Text, Cells etc.).

PS: I will use code markup later. Don't have the time to look into it now.

[jacob-carlborg]

I have fixed the issue with calling a non existing selector here: a3b0e15. The next problem is like you say with the call to autorelease. The issue isn't actually calling attribStr.autorelease, the issue is calling release at this line dwt/widgets/Control.d#L910. The issue is not the NSAttributedString being released, it's the NSString it's create with being released.

[WendleC]

Great news! I am glad to hear that the culprit has been found. Unfortunately, I haven't had time to look at the other examples.

[WendleC]

You create the str with NSString str = NSString.stringWith(chars[0 .. length]); I don't know what is happening behind the scenes, but if this is like Objective-C's [NSString stringWith...], then it need not be released (if it's the class method you are calling, instead of [[NSString alloc] initWith...].

[jacob-carlborg]

stringWith is a custom method used in DWT/SWT that doesn't exist in NSString. The implementation for D looks like this:

public static NSString stringWith(String str) {
    return stringWithUTF8String((str ~ '\0').ptr);
}

dwt/internal/cocoa/NSString.d#L44. The Java implementation looks like this:

public static NSString stringWith(String str) {
    char[] buffer = new char[str.length()];
    str.getChars(0, buffer.length, buffer, 0);
    return stringWithCharacters(buffer, buffer.length);
}

swt/internal/cocoa/NSString.java?id=v3550#n33. Would there be any differences with stringWithCharacters compared to stringWithUTF8String?

[jacob-carlborg]

I can't reproduce this, could you please try the latest master?

[WendleC]

Hi Jacob,

I'm sorry my Mac at work broke down a couple of months ago and I had it all
set up there. At the moment I'm very busy with various projects so I won't
have the time to set it all up at home and test it until into the middle of
January. Sorry about that. Christoph

On Mon, Dec 2, 2013 at 8:09 AM, jacob-carlborg notifications@github.comwrote:

I can't reproduce this, could you please try the latest master?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/6#issuecomment-29600468
.

[jacob-carlborg]

I see, no problem.