On Thu, Jan 12, 2017 at 02:42:52AM -0500, Boris Zbarsky wrote:
> On 1/12/17 2:30 AM, gsquel...@mozilla.com wrote:
> > This way all users of SomeClass only need to include SomeClass.h, not
> > SomeType.h, when they want to call SomeClass::foo.
>
> They don't need to have SomeType.h included merely to call SomeClass::foo.
> They have the forward-declaration in scope, so they can pass along SomeType*
> values they get from somewhere, and don't even have to forward-declare it
> themselves to do so. e.g. this would be a perfectly sane consumer of
> SomeClass:
>
> #include "SomeClass.h"
> #include "SomeOtherClass.h" // also forward-declares SomeType
>
> void PassLongFoo(SomeClass* inst)
> {
> inst->foo(SomeOtherClass::getSomeType());
> }
>
> where SomeOtherClass has a static getSomeType() returning SomeType*. None of
> this requires any of the files involved to include SomeType.h.
>
> What _does_ require including SomeType.h is if you plan to construct a
> SomeType, or manipulate SomeType instances in some way. But in that case,
> you really should be including SomeType.h yourself instead of relying on
> SomeClass to do it for you, in my opinion.
>
> > I can see how nice this can be for users of SomeClass.
>
> Until SomeClass stops using SomeType and those users stop compiling because
> they are still doing things with it but no longer getting the include
> courtesy of SomeClass. This is especially pernicious with unified
> compilation, because it can take some time to notice.
>
> > So I personally still prefer the coding style as is
>
> I do too.
+1
The sad part is that it's not followed enough.
Mike
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