Name problems with HTMLDocument, InternetExplorer and WebBrowser

[Dan Hipschman]

Hi all,

I'd like to submit a patch which makes widl output forward declarations
to the header file for coclass definitions.  Currently this is done only
if the coclass has its own forward declaration.  For example,

[ uuid(...) ] coclass Foo; 
[ uuid(...) ] coclass Bar { ... }; 

Foo will get declared (via typedef) in the header but Bar will not.  The
only problem is that when I fix widl it breaks the build in three places:

make[2]: Entering directory `/var/build/wine/dlls/mshtml'
In file included from conpoint.c:33:
mshtml_private.h:99: error: conflicting types for `HTMLDocument'
../../include/mshtml.h:26023: error: previous declaration of `HTMLDocument' was here

make[2]: Entering directory `/var/build/wine/dlls/shdocvw'
In file included from classinfo.c:26:
shdocvw.h:133: error: conflicting types for `WebBrowser'
../../include/exdisp.h:1907: error: previous declaration of `WebBrowser' was here
shdocvw.h:143: error: conflicting types for `InternetExplorer'
../../include/exdisp.h:1918: error: previous declaration of `InternetExplorer' was here

The problem is that the three names are declared coclasses in the IDL files
which generates code like this:

#ifndef __Foo_FWD_DEFINED__
#define __Foo_FWD_DEFINED__
typedef struct Foo Foo;
#endif /* defined __Foo_FWD_DEFINED__ */

and is included in the files shown above which redeclare the names like this:

typedef struct { ... } Foo;

There's actually an easy fix if we just change the latter declaration to

struct Foo { ... };

but I'm not sure this is not a kludge.  Do the names really represent the same
types, or is a namespace collision?

Thanks,
Dan

[Robert Shearman]

Dan Hipschman wrote:
> Hi all,
>
> I'd like to submit a patch which makes widl output forward declarations
> to the header file for coclass definitions.  Currently this is done only
> if the coclass has its own forward declaration.  For example,
>
> [ uuid(...) ] coclass Foo; 
> [ uuid(...) ] coclass Bar { ... };
>
> Foo will get declared (via typedef) in the header but Bar will not.  The
> only problem is that when I fix widl it breaks the build in three places:
>
> make[2]: Entering directory `/var/build/wine/dlls/mshtml'
> In file included from conpoint.c:33:
> mshtml_private.h:99: error: conflicting types for `HTMLDocument'
> ../../include/mshtml.h:26023: error: previous declaration of `HTMLDocument' was here
>
> There's actually an easy fix if we just change the latter declaration to
>
> struct Foo { ... };
>
> but I'm not sure this is not a kludge.  Do the names really represent the same
> types, or is a namespace collision?

This is just a namespace collision. A safer option might be to rename 
use FooImpl instead of Foo in the typedefs in mshtml_private.h and 
shdocvw.h, but your solution looks fine.

-- 
Rob Shearman

[Jacek Caban]

Dan Hipschman wrote:
> Hi all,
>
> I'd like to submit a patch which makes widl output forward declarations
> to the header file for coclass definitions.  Currently this is done only
> if the coclass has its own forward declaration.  For example,
>
> [ uuid(...) ] coclass Foo; 
> [ uuid(...) ] coclass Bar { ... };
>
> Foo will get declared (via typedef) in the header but Bar will not.  The
> only problem is that when I fix widl it breaks the build in three places:
>
> make[2]: Entering directory `/var/build/wine/dlls/mshtml'
> In file included from conpoint.c:33:
> mshtml_private.h:99: error: conflicting types for `HTMLDocument'
> ../../include/mshtml.h:26023: error: previous declaration of `HTMLDocument' was here
>
> make[2]: Entering directory `/var/build/wine/dlls/shdocvw'
> In file included from classinfo.c:26:
> shdocvw.h:133: error: conflicting types for `WebBrowser'
> ../../include/exdisp.h:1907: error: previous declaration of `WebBrowser' was here
> shdocvw.h:143: error: conflicting types for `InternetExplorer'
> ../../include/exdisp.h:1918: error: previous declaration of `InternetExplorer' was here
>
> The problem is that the three names are declared coclasses in the IDL files
> which generates code like this:
>
> #ifndef __Foo_FWD_DEFINED__
> #define __Foo_FWD_DEFINED__
> typedef struct Foo Foo;
> #endif /* defined __Foo_FWD_DEFINED__ */

IMO these forward declarations are useless and wrong. coclasses should 
not have a defined type as it's up to the developer how it will be 
implemented and clients should not use this type, but an interfaces 
instead. But it's only my opinion and if forward declarations are in 
midl, it should be fixed in widl.
> and is included in the files shown above which redeclare the names like this:
>
> typedef struct { ... } Foo;
>
> There's actually an easy fix if we just change the latter declaration to
>
> struct Foo { ... };

It seams to be the best solution.

Jacek