[Mesa-dev] [PATCH v2 05/12] mesa: add API_NUM

[Ian Romanick]

On 09/10/2012 09:41 AM, Imre Deak wrote:
> Needed by the next patch.
>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>   src/mesa/main/context.c |    2 ++
>   src/mesa/main/mtypes.h  |    2 ++
>   src/mesa/main/version.c |    3 +++
>   3 files changed, 7 insertions(+)
>
> diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
> index 6b28690..1167ea5 100644
> --- a/src/mesa/main/context.c
> +++ b/src/mesa/main/context.c
> @@ -1040,6 +1040,8 @@ _mesa_initialize_context(struct gl_context *ctx,
>         ctx->VertexProgram._MaintainTnlProgram = GL_TRUE;
>         ctx->Point.PointSprite = GL_TRUE;  /* always on for ES 2.x */
>         break;
> +   default:
> +      _mesa_problem(ctx, "Unknown API %d\n", ctx->API);
>      }
>
>      ctx->FirstTimeCurrent = GL_TRUE;
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index ba43e57..5fc3b8e 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -3340,6 +3340,8 @@ typedef enum
>      API_OPENGLES,
>      API_OPENGLES2,
>      API_OPENGL_CORE,
> +
> +   API_NUM,
>   } gl_api;

I'm not a fan of this.  As you noticed, it means you have to add 
unnecessary default cases to any switch statements involving gl_api. 
Doing this means that when a new API_* is added, some switch statement 
that needs to be updated may be missed.

There are two ways to handle this that I would prefer.

1. Add

     API_LAST = API_OPENGL_CORE

at the end of the enum.  Then use 'API_LAST + 1' in all the places where 
you now have API_NUM.

2. Do the above, but also add

#define API_NUM  (API_LAST + 1)

There may be some bikeshedding over the API_NUM name as well.

>
>   /**
> diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
> index bc7b1fa..7deb614 100644
> --- a/src/mesa/main/version.c
> +++ b/src/mesa/main/version.c
> @@ -322,6 +322,9 @@ _mesa_compute_version(struct gl_context *ctx)
>      case API_OPENGLES2:
>         compute_version_es2(ctx);
>         break;
> +   default:
> +      _mesa_problem(ctx, "unknown or unsupported API");
> +      break;
>      }
>
>   }
>