Re: CoreBase and ARC

[Stefan Bidigaray]

Oh well, I forgot to CC the list on my previous e-mail.  No problem, I committed a fix to this problem just now.  Can you try again and let me know if it works as expected?

Thanks

On Wed, Feb 18, 2015 at 10:51 AM, Stefan Bidigaray <stefanbidi@gmail.com> wrote:

So when CoreBase first came around ARC was at it's infancy and being able to seemingly go from CF to ObjC objects was a good idea.  All the "toll-free bridged" types have a construct similar to:

#ifdef __OBJC__
@class NSData;
@class NSMutableData;
typedef NSData* CFDataRef;
typedef NSMutableData* CFMutableDataRef;
#else
typedef const struct __CFData * CFDataRef;
typedef struct __CFData * CFMutableDataRef;
#endif

This is very handy, but after doing some research on ARC it requires explicit transferring control to C because ARC cannot keep up with what's going on in C structs.  See https://developer.apple.com/library/mac/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html if you're interested in the details.

The obvious compatibility solution here would be to get rid of those #ifdef's and always define CF types to be typedef struct ...

I would appreciate if David C. could confirm that this is the correct solution before committing, though.

On Tue, Feb 17, 2015 at 11:25 AM, Maxthon Chan <xcvista@me.com> wrote:

I am getting a bit of trouble compiling code with CoreBase and ARC at the same time. I am using latest trunk version of base and corebase on Ubuntu 14.04 LTS with clang 3.5. Here is the log:

$ make
This is gnustep-make 2.6.6. Type 'make print-gnustep-make-help' for help.
Making build-headers for framework CGIKit...
 Creating CGIKit.framework/Versions/H/Headers...
 Creating derived_src/.stamp...
 Creating CGIKit.framework/Versions/H/Resources...
 Updating Version/Current symlink...
Making all for framework CGIKit...
 Compiling file CGIApplication.m ...
In file included from CGIApplication.m:9:
In file included from ./CGIApplication.h:12:
In file included from ../CGIKit/CGIKitDefines.h:51:
In file included from /usr/local/include/GNUstep/CoreFoundation/CoreFoundation.h:36:
In file included from /usr/local/include/GNUstep/CoreFoundation/CFBundle.h:31:
In file included from /usr/local/include/GNUstep/CoreFoundation/CFURL.h:34:
/usr/local/include/GNUstep/CoreFoundation/CFString.h:538:15: error: ARC forbids Objective-C objects in struct
  CFStringRef theString;
              ^
In file included from CGIApplication.m:9:
In file included from ./CGIApplication.h:12:
In file included from ../CGIKit/CGIKitDefines.h:51:
In file included from /usr/local/include/GNUstep/CoreFoundation/CoreFoundation.h:48:
In file included from /usr/local/include/GNUstep/CoreFoundation/CFPropertyList.h:33:
In file included from /usr/local/include/GNUstep/CoreFoundation/CFStream.h:33:
/usr/local/include/GNUstep/CoreFoundation/CFSocket.h:61:13: error: ARC forbids Objective-C objects in struct
  CFDataRef address;
            ^
In file included from CGIApplication.m:9:
In file included from ./CGIApplication.h:12:
In file included from ../CGIKit/CGIKitDefines.h:51:
In file included from /usr/local/include/GNUstep/CoreFoundation/CoreFoundation.h:60:
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:76:12: error: ARC forbids Objective-C objects in struct
  CFURLRef systemID;
           ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:83:15: error: ARC forbids Objective-C objects in struct
  CFStringRef attributeName;
              ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:98:12: error: ARC forbids Objective-C objects in struct
  CFURLRef sourceURL;
           ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:111:19: error: ARC forbids Objective-C objects in struct
  CFDictionaryRef attributes;
                  ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:119:15: error: ARC forbids Objective-C objects in struct
  CFStringRef contentDescription;
              ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:126:15: error: ARC forbids Objective-C objects in struct
  CFStringRef replacementText;
              ^
/usr/local/include/GNUstep/CoreFoundation/CFXMLNode.h:146:15: error: ARC forbids Objective-C objects in struct
  CFStringRef dataString;
              ^
CGIApplication.m:30:65: error: expected method body
- (instancetype)_init __attribute__((objc_method_family(init))) NS_REPLACES_RECEIVER
                                                                ^
10 errors generated.
make[2]: *** [obj/CGIKit.obj/CGIApplication.m.o] Error 1
make[1]: *** [internal-framework-run-compile-submake] Error 2
make: *** [CGIKit.all.framework.variables] Error 2

And then I got this trying to check for “pesky typedefs":

$ clang -E $(gnustep-config --objc-flags) -fobjc-arc -I. -I.. CGIApplication.m
// … lines removed …
# 268 "/usr/local/include/GNUstep/CoreFoundation/CFBase.h"
typedef CFTypeRef CFPropertyListRef;





@class NSString;
@class NSMutableString;
typedef NSString * CFStringRef;
typedef NSMutableString * CFMutableStringRef;
# 294 "/usr/local/include/GNUstep/CoreFoundation/CFBase.h"
typedef const struct __CFAllocator * CFAllocatorRef;

typedef void* (*CFAllocatorAllocateCallBack)(CFIndex allocSize,
  CFOptionFlags hint, void *info);
// … lines removed …

The typedef here works “seemingly” well without ARC but it bites me in the ass when ARC is used.

Does this call for a change? How to do it?
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