[waffle] [PATCH 05/12] waffle: add waffle_display_info_json()

Frank Henigman fjhenigman at google.com
Thu Apr 21 20:25:36 UTC 2016


On Fri, Jan 8, 2016 at 7:40 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> On 6 January 2016 at 21:56, Frank Henigman <fjhenigman at google.com> wrote:
>> Duplicate wflinfo functionality in the API, with the difference that the
>> information is returned in JSON form.
>> The function has a parameter for including platform-specific information,
>> but it is ignored for now.
>>
>> Signed-off-by: Frank Henigman <fjhenigman at google.com>
>> ---
>>  include/waffle/waffle.h         |   5 +
>>  man/waffle_display.3.xml        |  19 +++
>>  src/waffle/api/waffle_display.c | 284 +++++++++++++++++++++++++++++++++++++++-
>>  src/waffle/waffle.def.in        |   1 +
>>  4 files changed, 308 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/waffle/waffle.h b/include/waffle/waffle.h
>> index df0218e..1800399 100644
>> --- a/include/waffle/waffle.h
>> +++ b/include/waffle/waffle.h
>> @@ -214,6 +214,11 @@ bool
>>  waffle_display_supports_context_api(struct waffle_display *self,
>>                                      int32_t context_api);
>>
>> +#if WAFFLE_API_VERSION >= 0x0106
>> +char*
>> +waffle_display_info_json(struct waffle_display *self, bool platform_too);
> The function does not work solely with the display, but it requires a
> (bound) context. Thus it does not really fit waffle naming scheme. I'm
> afraid that I'm short of suggestions though (barring my "returning
> json formatted data sounds iffy, lets use tokens" rant from earlier)
>
>
>> +#endif
>> +
>>  union waffle_native_display*
>>  waffle_display_get_native(struct waffle_display *self);
>>
>> diff --git a/man/waffle_display.3.xml b/man/waffle_display.3.xml
>> index 9896247..5358472 100644
>> --- a/man/waffle_display.3.xml
>> +++ b/man/waffle_display.3.xml
>> @@ -24,6 +24,7 @@
>>      <refname>waffle_display</refname>
>>      <refname>waffle_display_connect</refname>
>>      <refname>waffle_display_disconnect</refname>
>> +    <refname>waffle_display_info_json</refname>
>>      <refname>waffle_display_supports_context_api</refname>
>>      <refname>waffle_display_get_native</refname>
>>      <refpurpose>class <classname>waffle_display</classname></refpurpose>
>> @@ -58,6 +59,12 @@ struct waffle_display;
>>        </funcprototype>
>>
>>        <funcprototype>
>> +        <funcdef>char* <function>waffle_display_info_json</function></funcdef>
>> +        <paramdef>struct waffle_display *<parameter>self</parameter></paramdef>
>> +        <paramdef>bool <parameter>platform_info</parameter></paramdef>
>> +      </funcprototype>
>> +
>> +      <funcprototype>
>>          <funcdef>bool <function>waffle_display_supports_context_api</function></funcdef>
>>          <paramdef>struct waffle_display *<parameter>self</parameter></paramdef>
>>          <paramdef>int32_t <parameter>context_api</parameter></paramdef>
>> @@ -129,6 +136,18 @@ struct waffle_display;
>>        </varlistentry>
>>
>>        <varlistentry>
>> +        <term><function>waffle_display_info_json()</function></term>
>> +        <listitem>
>> +          <para>
>> +            Return a JSON string containing information about the current context on the given display, including Waffle platform and API, GL version/vendor/renderer and extensions.
>> +            If <parameter>platform_info</parameter> is true, platform-specific information (such as GLX or EGL versions and extensions) will be included as available.
>> +            Returns <constant>NULL</constant> on error.
>> +            The string should be deallocated with <citerefentry><refentrytitle><function>free</function></refentrytitle><manvolnum>3</manvolnum></citerefentry>.
>> +          </para>
>> +        </listitem>
>> +      </varlistentry>
>> +
>> +      <varlistentry>
>>          <term><function>waffle_display_supports_context_api()</function></term>
>>          <listitem>
>>            <para>
>> diff --git a/src/waffle/api/waffle_display.c b/src/waffle/api/waffle_display.c
>> index fa19462..7abe2ef 100644
>> --- a/src/waffle/api/waffle_display.c
>> +++ b/src/waffle/api/waffle_display.c
>> @@ -23,13 +23,61 @@
>>  // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>>  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
>>
>> +#include <ctype.h>
>> +#include <stdio.h>
>> +
>>  #include "api_priv.h"
>>
>> -#include "wcore_error.h"
>> +#include "json.h"
>> +
>> +#include "wcore_context.h"
>>  #include "wcore_display.h"
>> +#include "wcore_error.h"
>>  #include "wcore_platform.h"
>>  #include "wcore_util.h"
>>
>> +typedef unsigned int GLint;
>> +typedef unsigned int GLenum;
>> +typedef unsigned char GLubyte;
>> +
>> +enum {
>> +    // Copied from <GL/gl*.h>.
>> +    GL_NO_ERROR = 0,
>> +
>> +    GL_CONTEXT_FLAGS = 0x821e,
>> +    GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT = 0x00000001,
>> +    GL_CONTEXT_FLAG_DEBUG_BIT              = 0x00000002,
>> +    GL_CONTEXT_FLAG_ROBUST_ACCESS_BIT_ARB  = 0x00000004,
>> +
>> +    GL_VENDOR                              = 0x1F00,
>> +    GL_RENDERER                            = 0x1F01,
>> +    GL_VERSION                             = 0x1F02,
>> +    GL_EXTENSIONS                          = 0x1F03,
>> +    GL_NUM_EXTENSIONS                      = 0x821D,
>> +    GL_SHADING_LANGUAGE_VERSION            = 0x8B8C,
>> +};
>> +
>> +#ifndef _WIN32
>> +#define APIENTRY
>> +#else
>> +#ifndef APIENTRY
>> +#define APIENTRY __stdcall
>> +#endif
>> +#endif
>> +
>> +static GLenum (APIENTRY *glGetError)(void);
>> +static void (APIENTRY *glGetIntegerv)(GLenum pname, GLint *params);
>> +static const GLubyte * (APIENTRY *glGetString)(GLenum name);
>> +static const GLubyte * (APIENTRY *glGetStringi)(GLenum name, GLint i);
>> +
>> +#if defined(__GNUC__)
>> +#define NORETURN __attribute__((noreturn))
>> +#elif defined(_MSC_VER)
>> +#define NORETURN __declspec(noreturn)
>> +#else
>> +#define NORETURN
>> +#endif
>> +
>>  WAFFLE_API struct waffle_display*
>>  waffle_display_connect(const char *name)
>>  {
>> @@ -90,6 +138,240 @@ waffle_display_supports_context_api(
>>                                                              context_api);
>>  }
>>
>> +static int
>> +parse_version(const char *version)
>> +{
>> +    int count, major, minor;
>> +
>> +    if (version == NULL)
>> +        return 0;
>> +
>> +    while (*version != '\0' && !isdigit(*version))
>> +        version++;
>> +
>> +    count = sscanf(version, "%d.%d", &major, &minor);
>> +    if (count != 2)
>> +        return 0;
>> +
>> +    if (minor > 9)
>> +        return 0;
>> +
>> +    return (major * 10) + minor;
>> +}
>> +
>> +static void
>> +add_context_flags(struct json *jj)
>> +{
>> +    static struct {
>> +        GLint flag;
>> +        char *str;
>> +    } flags[] = {
>> +        { GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT, "FORWARD_COMPATIBLE" },
>> +        { GL_CONTEXT_FLAG_DEBUG_BIT, "DEBUG" },
>> +        { GL_CONTEXT_FLAG_ROBUST_ACCESS_BIT_ARB, "ROBUST_ACCESS" },
>> +    };
>> +    int flag_count = sizeof(flags) / sizeof(flags[0]);
>> +    GLint context_flags = 0;
>> +
>> +    glGetIntegerv(GL_CONTEXT_FLAGS, &context_flags);
>> +    if (glGetError() != GL_NO_ERROR)
>> +        return json_append(jj, json_str("WFLINFO_GL_ERROR"));
>> +
>> +    if (context_flags == 0)
>> +        return json_append(jj, json_num(0));
>> +
>> +    for (int i = 0; i < flag_count; i++) {
>> +        if ((flags[i].flag & context_flags) != 0) {
>> +            json_append(jj, json_str(flags[i].str));
>> +            context_flags = context_flags & ~flags[i].flag;
>> +        }
>> +    }
>> +    for (int i = 0; context_flags != 0; context_flags >>= 1, i++) {
>> +        if ((context_flags & 1) != 0) {
>> +            json_append(jj, json_num(1 << i));
>> +        }
>> +    }
>> +}
>> +
>> +static void
>> +add_extensions(struct json *jj, bool use_stringi)
>> +{
>> +    GLint count = 0, i;
>> +    const char *ext;
>> +
>> +    if (use_stringi) {
>> +        glGetIntegerv(GL_NUM_EXTENSIONS, &count);
>> +        if (glGetError() != GL_NO_ERROR) {
>> +            json_append(jj, json_str("WFLINFO_GL_ERROR"));
>> +        } else {
>> +            for (i = 0; i < count; i++) {
>> +                ext = (const char *) glGetStringi(GL_EXTENSIONS, i);
>> +                if (glGetError() != GL_NO_ERROR)
>> +                    ext = "WFLINFO_GL_ERROR";
>> +                json_append(jj, json_str(ext));
>> +            }
>> +        }
>> +    } else {
>> +        const char *extensions = (const char *) glGetString(GL_EXTENSIONS);
>> +        if (glGetError() != GL_NO_ERROR)
>> +            json_append(jj, json_str("WFLINFO_GL_ERROR"));
>> +        else
>> +            json_append(jj, json_split(extensions, " "));
>> +    }
>> +}
>> +
>> +static void
>> +add_generic_info(struct json *jj, struct wcore_context *ctx)
>> +{
>> +    int32_t dl;
>> +    //XXX this pattern seems to occur repeatedly - do we need two sets of enums?
> I'm afraid we do. The whole topic is a bit messy, but the gist is that
> - because we have the GL* library that does not imply that we can have
> a context of said API and vice-versa.
>
>> +    switch (ctx->context_api) {
>> +        case WAFFLE_CONTEXT_OPENGL:     dl = WAFFLE_DL_OPENGL;      break;
>> +        case WAFFLE_CONTEXT_OPENGL_ES1: dl = WAFFLE_DL_OPENGL_ES1;  break;
>> +        case WAFFLE_CONTEXT_OPENGL_ES2: dl = WAFFLE_DL_OPENGL_ES2;  break;
>> +        case WAFFLE_CONTEXT_OPENGL_ES3: dl = WAFFLE_DL_OPENGL_ES3;  break;
>> +        default:
>> +            abort();
> This feels excessive. Set an error and bail out ?

I'll change to assert(false).  I think we want at least that, because
the value has been validated by this point so we should never get
here.

>
>> +            break;
>> +    }
>> +
>> +    glGetError = waffle_dl_sym(dl, "glGetError");
>> +    if (!glGetError)
>> +        return json_append(jj, NULL);
>> +
>> +    glGetIntegerv = waffle_dl_sym(dl, "glGetIntegerv");
>> +    if (!glGetIntegerv)
>> +        return json_append(jj, NULL);
>> +
>> +    glGetString = waffle_dl_sym(dl, "glGetString");
>> +    if (!glGetString)
>> +        return json_append(jj, NULL);
>> +
>> +    // Retrieving GL functions is tricky. When glGetStringi is supported, here
>> +    // are some boggling variations as of 2014-11-19:
>> +    //   - Mali drivers on EGL 1.4 expose glGetStringi statically from
>> +    //     libGLESv2 but not dynamically from eglGetProcAddress. The EGL 1.4 spec
>> +    //     permits this behavior.
>> +    //   - EGL 1.5 requires that eglGetStringi be exposed dynamically through
>> +    //     eglGetProcAddress. Exposing statically with dlsym is optional.
>> +    //   - Windows requires that glGetStringi be exposed dynamically from
>> +    //     wglGetProcAddress. Exposing statically from GetProcAddress (Window's
>> +    //     dlsym equivalent) is optional.
>> +    //   - Mesa drivers expose glGetStringi statically from libGL and libGLESv2
>> +    //     and dynamically from eglGetProcAddress and glxGetProcAddress.
>> +    //   - Mac exposes glGetStringi only statically.
>> +    //
>> +    // Try waffle_dl_sym before waffle_get_proc_address because
>> +    // (1) egl/glXProcAddress can return invalid non-null pointers for
>> +    // unsupported functions and (2) dlsym returns non-null if and only if the
>> +    // library exposes the symbol.
>> +    glGetStringi = waffle_dl_sym(dl, "glGetStringi");
>> +    if (!glGetStringi) {
>> +        glGetStringi = waffle_get_proc_address("glGetStringi");
>> +    }
>> +
>> +    while(glGetError() != GL_NO_ERROR) {
>> +        /* Clear all errors */
>> +    }
>> +
> As mentioned elsewhere - why the loop (and yes same question goes for
> the original in wflinfo) ?

According to the man page "glGetError should always be called in a
loop, until it returns GL_NO_ERROR, if all error flags are to be
reset."

>
>> +    const char *vendor = (const char *) glGetString(GL_VENDOR);
>> +    if (glGetError() != GL_NO_ERROR || vendor == NULL) {
>> +        vendor = "WFLINFO_GL_ERROR";
>> +    }
>> +
>> +    const char *renderer = (const char *) glGetString(GL_RENDERER);
>> +    if (glGetError() != GL_NO_ERROR || renderer == NULL) {
>> +        renderer = "WFLINFO_GL_ERROR";
>> +    }
>> +
>> +    const char *version_str = (const char *) glGetString(GL_VERSION);
>> +    if (glGetError() != GL_NO_ERROR || version_str == NULL) {
>> +        version_str = "WFLINFO_GL_ERROR";
>> +    }
>> +
> Please drop the extra curly brackets from the last 4 if statements.
> Afaict with MSVC2013 U4 (our min requirement) things should just work
> ?
>
>> +    assert(ctx->display->platform->waffle_platform);
>> +    const char *platform =
>> +            wcore_enum_to_string(ctx->display->platform->waffle_platform);
>> +    assert(platform != NULL);
>> +
>> +    assert(ctx->context_api);
>> +    const char *api = wcore_enum_to_string(ctx->context_api);
>> +    assert(api != NULL);
>> +
>> +    json_appendv(jj,
>> +        "waffle", "{",
>> +            "platform", json_str(platform),
>> +            "api",      json_str(api),
>> +         "}",
>> +        "opengl", "{",
>> +            "vendor",   json_str(vendor),
>> +            "renderer", json_str(renderer),
>> +            "version",  json_str(version_str),
>> +        "}", "");
>> +
>> +    int version = parse_version(version_str);
>> +
>> +    if (ctx->context_api == WAFFLE_CONTEXT_OPENGL && version >= 31) {
>> +        json_appendv(jj, "context_flags", "[", "");
>> +        add_context_flags(jj);
>> +        json_append(jj, "]");
>> +    }
>> +
>> +    // OpenGL and OpenGL ES >= 3.0 support glGetStringi(GL_EXTENSION, i).
>> +    const bool use_getstringi = version >= 30;
>> +
>> +    if (!glGetStringi && use_getstringi)
>> +        return json_append(jj, NULL);
>> +
>> +    // There are two exceptional cases where wflinfo may not get a
>> +    // version (or a valid version): one is in gles1 and the other
>> +    // is GL < 2.0. In these cases do not return WFLINFO_GL_ERROR,
>> +    // return None. This is preferable to returning WFLINFO_GL_ERROR
>> +    // because it creates a consistant interface for parsers
>> +    const char *language_str = "None";
>> +    if ((ctx->context_api == WAFFLE_CONTEXT_OPENGL && version >= 20) ||
>> +            ctx->context_api == WAFFLE_CONTEXT_OPENGL_ES2 ||
>> +            ctx->context_api == WAFFLE_CONTEXT_OPENGL_ES3) {
>> +        language_str = (const char *) glGetString(GL_SHADING_LANGUAGE_VERSION);
>> +        if (glGetError() != GL_NO_ERROR || language_str == NULL) {
>> +            language_str = "WFLINFO_GL_ERROR";
>> +        }
>> +    }
>> +
>> +    json_appendv(jj, "shading_language_version", json_str(language_str), "");
>> +    json_appendv(jj, "extensions", "[", "");
>> +    add_extensions(jj, use_getstringi);
>> +    json_append(jj, "]");
>> +}
>> +
>> +WAFFLE_API char*
> Please add space between char and *
>
>> +waffle_display_info_json(struct waffle_display *self, bool platform_too)
>> +{
>> +    struct wcore_display *wc_self = wcore_display(self);
>> +
>> +    const struct api_object *obj_list[] = {
>> +        wc_self ? &wc_self->api : NULL,
>> +    };
>> +
>> +    if (!api_check_entry(obj_list, 1))
>> +        return NULL;
>> +
>> +    if (!wc_self->current_context) {
>> +        wcore_errorf(WAFFLE_ERROR_UNKNOWN, "no current context");
>> +        return NULL;
>> +    }
>> +
>> +    struct json *jj = json_init();
>> +    if (!jj)
> Set the error state ?

It will only fail if it can't get memory, in which case I don't see
the point in setting error state.
Throughout waffle we just return NULL if calloc() fails, without
setting an error.

>
>> +        return NULL;
>> +
>> +    json_appendv(jj, "{", "generic", "{", "");
>> +    add_generic_info(jj, wc_self->current_context);
>> +    json_appendv(jj, "}", "}", "");
>> +
> A similar question if the json library fails at some point ?

Similar answer.  (:

>
>> +    return json_destroy(jj);
>> +}
>
> -Emil


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