Well an idea, which is this:
#define CFSTR(string) @(string)
And if the user is using clang 3.2+, it will automatically convert
the string in question into a constant NSString object, which is, in
turn, bridged back to CF.
发自我的 iPad
在 2013-3-10，22:58，Luboš Doležel <address@hidden> 写道：
Hi,
I've started working on toll-free bridging support for
gnustep-corebase. I'm pushing my work to github:
https://github.com/LubosD/gnustep-corebase
So far I have NSString/CFString and NSArray/CFArray somewhat
working and I'm moving to other types.
The bridging is implemented via a helper category, so nothing in
Base had to be touched for bridging to work in both directions.
Given CoreBase's alpha state, it's the only feasible option anyway,
I guess.
There is one thing I cannot easily fix, though. @"Strings". On OS
X, @"string" is a direct equivalent of CFSTR("string"). In other
words, a constant CFString instance is created in the resulting
binary.
On Linux, though, we get this by default:
http://gcc.gnu.org/onlinedocs/gcc/Constant-string-objects.html I
don't see any reasonable/maintainable way of making this struct
working with CFString; I believe the best way forward is to adapt
Apple's approach and generate __CFString structs for every @"aaa".
This is where ABI comes in, so David, what is your opinion? My
suggestion:
1) Have clang generate __CFString's 2) Adapt NSConstantString to
support this new struct layout 3) Make the CFTypeID of CFString
constant forever (this is what they had to do in Apple CF/CFLite),
as it will be part of the ABI
As an aside, it should be discussed whether CoreBase's __CFString
should contain a "hashCode" field. The one from Apple does not. I
would make it go away for two reasons:
1) It gives me a headache in Darling, because this extra field
doesn't fit into the original struct when doing fixups :-) 2) It
makes the hash computation part of the ABI
Bye, -- Luboš Doležel
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