[Mesa-stable] [PATCH] mesa/extensions: Enable overriding permanently enabled extensions

[Nanley Chery]

This patch has been reviewed and tested:
http://lists.freedesktop.org/archives/mesa-dev/2015-November/101027.html

On Sun, Nov 22, 2015 at 12:30 PM, Nanley Chery <nanleychery at gmail.com>
wrote:

> From: Nanley Chery <nanley.g.chery at intel.com>
>
> Provide the ability to prevent any permanently enabled extension
> from appearing in the string returned by glGetString[i]().
>
> Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
> ---
>  src/mesa/main/extensions.c | 64
> +++++++++++++++++-----------------------------
>  1 file changed, 24 insertions(+), 40 deletions(-)
>
> diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
> index 01cfdf1..fa50cb6 100644
> --- a/src/mesa/main/extensions.c
> +++ b/src/mesa/main/extensions.c
> @@ -40,7 +40,6 @@
>  struct gl_extensions _mesa_extension_override_enables;
>  struct gl_extensions _mesa_extension_override_disables;
>  static char *extra_extensions = NULL;
> -static char *cant_disable_extensions = NULL;
>
>
>  /**
> @@ -68,29 +67,30 @@ const struct mesa_extension _mesa_extension_table[] = {
>  #undef EXT
>  };
>
> +static bool disabled_extensions[ARRAY_SIZE(_mesa_extension_table)];
>
>  /**
>   * Given an extension name, lookup up the corresponding member of struct
> - * gl_extensions and return that member's offset (in bytes).  If the name
> is
> - * not found in the \c _mesa_extension_table, return 0.
> + * gl_extensions and return that member's index.  If the name is
> + * not found in the \c _mesa_extension_table, return -1.
>   *
>   * \param name Name of extension.
> - * \return Offset of member in struct gl_extensions.
> + * \return Index of member in struct gl_extensions.
>   */
> -static size_t
> -name_to_offset(const char* name)
> +static int
> +name_to_index(const char* name)
>  {
>     unsigned i;
>
>     if (name == 0)
> -      return 0;
> +      return -1;
>
>     for (i = 0; i < ARRAY_SIZE(_mesa_extension_table); ++i) {
>        if (strcmp(name, _mesa_extension_table[i].name) == 0)
> -        return _mesa_extension_table[i].offset;
> +        return i;
>     }
>
> -   return 0;
> +   return -1;
>  }
>
>  /**
> @@ -206,11 +206,11 @@ _mesa_enable_sw_extensions(struct gl_context *ctx)
>   * \return offset of extensions withint `ext' or 0 if extension is not
> known
>   */
>  static size_t
> -set_extension(struct gl_extensions *ext, const char *name, GLboolean
> state)
> +set_extension(struct gl_extensions *ext, int i, GLboolean state)
>  {
>     size_t offset;
>
> -   offset = name_to_offset(name);
> +   offset = i < 0 ? 0 : _mesa_extension_table[i].offset;
>     if (offset != 0 && (offset != o(dummy_true) || state != GL_FALSE)) {
>        ((GLboolean *) ext)[offset] = state;
>     }
> @@ -240,12 +240,6 @@ get_extension_override( struct gl_context *ctx )
>  {
>     override_extensions_in_context(ctx);
>
> -   if (cant_disable_extensions != NULL) {
> -      _mesa_problem(ctx,
> -                    "Trying to disable permanently enabled extensions:
> %s",
> -                   cant_disable_extensions);
> -   }
> -
>     if (extra_extensions == NULL) {
>        return calloc(1, sizeof(char));
>     } else {
> @@ -257,7 +251,7 @@ get_extension_override( struct gl_context *ctx )
>
>
>  /**
> - * \brief Free extra_extensions and cant_disable_extensions strings
> + * \brief Free extra_extensions string
>   *
>   * These strings are allocated early during the first context creation by
>   * _mesa_one_time_init_extension_overrides.
> @@ -266,7 +260,6 @@ static void
>  free_unknown_extensions_strings(void)
>  {
>     free(extra_extensions);
> -   free(cant_disable_extensions);
>  }
>
>
> @@ -295,22 +288,20 @@ _mesa_one_time_init_extension_overrides(void)
>
>     /* extra_exts: List of unrecognized extensions. */
>     extra_extensions = calloc(ALIGN(strlen(env_const) + 2, 4),
> sizeof(char));
> -   cant_disable_extensions = calloc(ALIGN(strlen(env_const) + 2, 4),
> sizeof(char));
>
>     /* Copy env_const because strtok() is destructive. */
>     env = strdup(env_const);
>
>     if (env == NULL ||
> -       extra_extensions == NULL ||
> -       cant_disable_extensions == NULL) {
> +       extra_extensions == NULL) {
>        free(env);
>        free(extra_extensions);
> -      free(cant_disable_extensions);
>        return;
>     }
>
>     for (ext = strtok(env, " "); ext != NULL; ext = strtok(NULL, " ")) {
>        int enable;
> +      int i;
>        bool recognized;
>        switch (ext[0]) {
>        case '+':
> @@ -326,7 +317,8 @@ _mesa_one_time_init_extension_overrides(void)
>           break;
>        }
>
> -      offset = set_extension(&_mesa_extension_override_enables, ext,
> enable);
> +      i = name_to_index(ext);
> +      offset = set_extension(&_mesa_extension_override_enables, i,
> enable);
>        if (offset != 0 && (offset != o(dummy_true) || enable != GL_FALSE))
> {
>           ((GLboolean *) &_mesa_extension_override_disables)[offset] =
> !enable;
>           recognized = true;
> @@ -334,14 +326,12 @@ _mesa_one_time_init_extension_overrides(void)
>           recognized = false;
>        }
>
> -      if (!recognized) {
> -         if (enable) {
> -            strcat(extra_extensions, ext);
> -            strcat(extra_extensions, " ");
> -         } else if (offset == o(dummy_true)) {
> -            strcat(cant_disable_extensions, ext);
> -            strcat(cant_disable_extensions, " ");
> -         }
> +      if (i >= 0)
> +         disabled_extensions[i] = !enable;
> +
> +      if (!recognized && enable) {
> +         strcat(extra_extensions, ext);
> +         strcat(extra_extensions, " ");
>        }
>     }
>
> @@ -355,13 +345,6 @@ _mesa_one_time_init_extension_overrides(void)
>     } else if (extra_extensions[len - 1] == ' ') {
>        extra_extensions[len - 1] = '\0';
>     }
> -   len = strlen(cant_disable_extensions);
> -   if (len == 0) {
> -      free(cant_disable_extensions);
> -      cant_disable_extensions = NULL;
> -   } else if (cant_disable_extensions[len - 1] == ' ') {
> -      cant_disable_extensions[len - 1] = '\0';
> -   }
>  }
>
>
> @@ -402,7 +385,8 @@ _mesa_extension_supported(const struct gl_context
> *ctx, extension_index i)
>     const bool *base = (bool *) &ctx->Extensions;
>     const struct mesa_extension *ext = _mesa_extension_table + i;
>
> -   return (ctx->Version >= ext->version[ctx->API]) && base[ext->offset];
> +   return !disabled_extensions[i] &&
> +          (ctx->Version >= ext->version[ctx->API]) && base[ext->offset];
>  }
>
>  /**
> --
> 2.6.2
>
>
>
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