[Mesa-dev] [PATCH shader-db 3/3] run: add extension_in_string() helper

[Timothy Arceri]

On 21/08/17 20:27, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov at collabora.com>
> 
> memmem() does not attribute what the character after the searched string
> is. Thus it will flag even when haystack is "foobar" while we're looking
> for "foo".
> 
> Pull a small helper (based on piglit) that correctly handles this and use
> it.
> 
> Note: when parsing through the shader we have a non-zero terminated
> needle, let's keep the memmem in there for now.
> 
> Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
> ---
>   run.c | 43 +++++++++++++++++++++++++++++++++++--------
>   1 file changed, 35 insertions(+), 8 deletions(-)
> 
> diff --git a/run.c b/run.c
> index d0d4598..0691d33 100644
> --- a/run.c
> +++ b/run.c
> @@ -69,6 +69,35 @@ struct shader {
>       int type;
>   };
>   
> +static bool
> +extension_in_string(const char *haystack, const char *needle)
> +{
> +    const unsigned needle_len = strlen(needle);
> +
> +    if (needle_len == 0)
> +        return false;
> +
> +    while (true) {
> +        const char *const s = strstr(haystack, needle);
> +
> +        if (s == NULL)
> +            return false;
> +
> +        if (s[needle_len] == ' ' || s[needle_len] == '\0')
> +            return true;
> +
> +        /* strstr found an extension whose name begins with
> +         * needle, but whose name is not equal to needle.
> +         * Restart the search at s + needle_len so that we
> +         * don't just find the same extension again and go
> +         * into an infinite loop.
> +         */
> +        haystack = s + needle_len;
> +    }
> +
> +    return false;
> +}
> +
>   static struct shader *
>   get_shaders(const struct context_info *core, const struct context_info *compat,
>               const char *text, size_t text_size,
> @@ -141,8 +170,8 @@ get_shaders(const struct context_info *core, const struct context_info *compat,
>           extension_text += 1;
>           const char *newline = memchr(extension_text, '\n',
>                                        end_text - extension_text);
> -        if (memmem(info->extension_string, info->extension_string_len,
> -                   extension_text, newline - extension_text) == NULL) {
> +        if (memmem(info->extension_string, info->extension_string_len,
> +                   extension_text, newline - extension_text) == NULL) {
>               fprintf(stderr, "SKIP: %s requires unavailable extension %.*s\n",
>                       shader_name, (int)(newline - extension_text), extension_text);
>               return NULL;
> @@ -415,7 +444,7 @@ main(int argc, char **argv)
>           return -1;
>       }
>   
> -    if (!strstr(client_extensions, "EGL_MESA_platform_gbm")) {
> +    if (!extension_in_string(client_extensions, "EGL_MESA_platform_gbm")) {
>           fprintf(stderr, "ERROR: Missing EGL_MESA_platform_gbm\n");
>           return -1;
>       }
> @@ -458,7 +487,7 @@ main(int argc, char **argv)
>       };
>       for (int i = 0; i < ARRAY_SIZE(egl_extension); i++) {
>           const char *extension_string = eglQueryString(egl_dpy, EGL_EXTENSIONS);
> -        if (strstr(extension_string, egl_extension[i]) == NULL) {
> +        if (!extension_in_string(extension_string, egl_extension[i])) {
>               fprintf(stderr, "ERROR: Missing %s\n", egl_extension[i]);
>               ret = -1;
>               goto egl_terminate;
> @@ -530,8 +559,7 @@ main(int argc, char **argv)
>   
>           core.max_glsl_version = get_glsl_version();
>   
> -        if (memmem(core.extension_string, core.extension_string_len,
> -                   "GL_KHR_debug", strlen("GL_KHR_debug")) == NULL) {
> +        if (!extension_in_string(core.extension_string, "GL_KHR_debug")) {
>               fprintf(stderr, "ERROR: Missing GL_KHR_debug\n");
>               ret = -1;
>               goto egl_terminate;
> @@ -556,8 +584,7 @@ main(int argc, char **argv)
>   
>           compat.max_glsl_version = get_glsl_version();
>   
> -        if (memmem(compat.extension_string, compat.extension_string_len,
> -                   "GL_KHR_debug", strlen("GL_KHR_debug")) == NULL) {
> +        if (!extension_in_string(compat.extension_string, "GL_KHR_debug")) {

Hi Emil,

I haven't looked into why but this segfaults when running on i965. 
Reverting these three patches makes things work again.


>               fprintf(stderr, "ERROR: Missing GL_KHR_debug\n");
>               ret = -1;
>               goto egl_terminate;
>