Re: [PATCH 5/5] widl: Generate helper macros for WinRT implementation.

[Jacek Caban]

Hi Rémi,

On 19.02.2021 12:04, Rémi Bernon wrote:
> This generates additional macros to help keeping implementation simple,
> guarded with WIDL_USING ifdefs, like this:
>  #ifdef WIDL_USING_WINDOWS_FOO_IFOO

I would find it more readable if we didn't follow all-uppercase for 
macro rule here, something like:

#define WIDL_using_Windows_Foo_IFoo

But it's a matter of taste, so I'm mentioning it just for consideration.
>  #define IFooVtbl __x_ABI_CWindows_CFoo_CIFooVtbl
>  #define IFoo __x_ABI_CWindows_CFoo_CIFoo

Typedefs for those would express it a bit more precisely in C (although 
we will need macros for other things anyway, so...).
>  #define IFoo_DoFoo __x_ABI_CWindows_CFoo_CIFoo_DoFoo
>  #endif /* WIDL_USING_WINDOWS_FOO_IFOO */
>
> Implementation files can define the desired WIDL_USING preprocessor
> macros before including the header, and then implement or use the
> interface methods with the simple non-prefixed names instead.

How about extending it a bit more to allow specifying entire namespaces 
in using statements, so something like:

#define WIDL_using_Windows_Foo

would have an effect on all interfaces in this exact namespace.
> Signed-off-by: Rémi Bernon
>
> tools/widl/header.c    | 68 ++++++++++++++++++++++++++++++++++++++++++
>   tools/widl/typetree.c  | 19 ++++++++++++
>   tools/widl/widltypes.h |  1 +
>   3 files changed, 88 insertions(+)
>
> diff --git a/tools/widl/header.c b/tools/widl/header.c
> index 82aad0f11ca..8ca74d5a6f4 100644
> --- a/tools/widl/header.c
> +++ b/tools/widl/header.c
> @@ -48,6 +48,8 @@ static void write_type_v(FILE *f, const decl_spec_t *t, int is_field, int declon
>   static void write_apicontract_guard_start(FILE *header, const expr_t *expr);
>   static void write_apicontract_guard_end(FILE *header, const expr_t *expr);
>
> +static void write_widl_using_macros(FILE *header, type_t *iface);
> - static void indent(FILE *h, int delta)
> {
>   int c;
>
> @@ -604,6 +606,7 @@ static void write_type_definition(FILE *f, type_t *t, int declonly)
>           fprintf(f, "#else\n");
>           write_type_left(f, &ds, NAME_C, declonly, TRUE);
>           fprintf(f, ";\n");
> -
>    if (winrt_mode) write_widl_using_macros(f, t);
>     fprintf(f, "#endif\n\n");
> }
> if (contract) write_apicontract_guard_end(f, contract);
>
> @@ -1536,6 +1539,70 @@ static void write_com_interface_start(FILE *header, const type_t *iface)
>     fprintf(header,"#define __%s_%sINTERFACE_DEFINED__\n\n", iface->c_name, dispinterface ? "DISP" : "");
>   }
>
> +static char *get_winrt_guard_macro(type_t *iface)
> +{
> - unsigned int len;
> - char *macro, *tmp = (char *)iface->c_name;
> - int i;
> -
> - if (!strncmp(tmp, "__x", 3)) tmp += 3;
> - if (!strncmp(tmp, "_ABI", 4)) tmp += 4;
> - macro = xstrdup(tmp);
> -
> - len = strlen(macro) + 1;
> - for (tmp = strstr(macro, "__F"); tmp; tmp = strstr(tmp, "__F"))
> -
>    memmove(tmp + 1, tmp + 3, len - (tmp - macro) - 3);
> - for (tmp = strstr(macro, "__C"); tmp; tmp = strstr(tmp, "__C"))
> -
>    memmove(tmp + 1, tmp + 3, len - (tmp - macro) - 3);
> - for (tmp = strstr(macro, "_C"); tmp; tmp = strstr(tmp, "_C"))
> -
>    memmove(tmp + 1, tmp + 2, len - (tmp - macro) - 2);
> -
> - for (i = strlen(macro); i > 0; --i) macro[i - 1] = toupper(macro[i - 1]);
> -
> - return macro;
>
> +}

Could you just compute it from namespace and name stored in type_t 
instead of parsing a previously computed string? It looks like a job for 
format_namespace().

Thanks,

Jacek