libclang: Get interface name of a category (`CXCursor_ObjCCategoryImplDecl`)

[piegamesde]

Given the following code

@implementation NSDateFormatter (MyInterface)
…
@end

and a CXCursor pointing to it of kind CXCursor_ObjCCategoryImplDecl: How can I get the name of the interface being extended here? clang_getCursorDisplayName only gives me the category name, but I also need the original name.

[AaronBallman]

I think you have to walk from the impl to the category decl, and from the category decl to the protocols.

(Untested) I think clang_getCanonicalCursor() will go from the category impl declaration to the category declaration. From there, perhaps you can use clang_Type_getNumObjCProtocolRefs()/clang_Type_getObjCProtocolDecl() to get the number of protocol references and each reference.

[piegamesde]

Thank you for your help! As it turns out, I've confused Foo : Bar and Foo (Bar). So this is not a protocol whose name I'm trying to get, but the name of the interface being extended by the category. I've updated the issue accordingly

[AaronBallman]

I don't think we currently expose any APIs to get that information; I think you have to visit the children of interface node and look for the categories that way. However, if you wanted to submit a patch to add the functionality, we'd certainly consider one. CC @rjmccall in case I've missed something in the libclang APIs, as Objective-C is not my strong suit.