/*
 * (C) Copyright IBM Corporation 2002, 2004
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file dri_util.c
 * DRI utility functions.
 *
 * This module acts as glue between GLX and the actual hardware driver.  A DRI
 * driver doesn't really \e have to use any of this - it's optional.  But, some
 * useful stuff is done here that otherwise would have to be duplicated in most
 * drivers.
 *
 * Basically, these utility functions take care of some of the dirty details of
 * screen initialization, context creation, context binding, DRM setup, etc.
 *
 * These functions are compiled into each DRI driver so libGL.so knows nothing
 * about them.
 */


#include <stdbool.h>
#include "dri_util.h"
#include "dri_context.h"
#include "dri_screen.h"
#include "dri_drawable.h"
#include "util/u_endian.h"
#include "util/u_memory.h"
#include "util/driconf.h"
#include "main/framebuffer.h"
#include "main/version.h"
#include "main/debug_output.h"
#include "main/errors.h"
#include "loader/loader.h"
#include "mesa_interface.h"
#include "loader_dri_helper.h"
#include "pipe-loader/pipe_loader.h"
#include "pipe/p_screen.h"

driOptionDescription __dri2ConfigOptions[] = {
      DRI_CONF_SECTION_DEBUG
         DRI_CONF_GLX_EXTENSION_OVERRIDE()
         DRI_CONF_INDIRECT_GL_EXTENSION_OVERRIDE()
      DRI_CONF_SECTION_END

      DRI_CONF_SECTION_PERFORMANCE
         DRI_CONF_VBLANK_MODE(DRI_CONF_VBLANK_DEF_INTERVAL_1)
         DRI_CONF_BLOCK_ON_DEPLETED_BUFFERS(false)
      DRI_CONF_SECTION_END
};

/*****************************************************************/
/** \name Screen handling functions                              */
/*****************************************************************/
/*@{*/

static void
setupLoaderExtensions(struct dri_screen *screen,
                      const __DRIextension **extensions)
{
   static const struct dri_extension_match matches[] = {
       {__DRI_IMAGE_LOOKUP, 1, offsetof(struct dri_screen, dri2.image), true},
       {__DRI_SWRAST_LOADER, 1, offsetof(struct dri_screen, swrast_loader), true},
       {__DRI_IMAGE_LOADER, 1, offsetof(struct dri_screen, image.loader), true},
       {__DRI_MUTABLE_RENDER_BUFFER_LOADER, 1, offsetof(struct dri_screen, mutableRenderBuffer.loader), true},
       {__DRI_KOPPER_LOADER, 1, offsetof(struct dri_screen, kopper_loader), true},
   };
   loader_bind_extensions(screen, matches, ARRAY_SIZE(matches), extensions);
}

/**
 * This is the first entrypoint in the driver called by the DRI driver loader
 * after dlopen()ing it.
 *
 * It's used to create global state for the driver across contexts on the same
 * Display.
 */
struct dri_screen *
driCreateNewScreen3(int scrn, int fd,
                    const __DRIextension **loader_extensions,
                    enum dri_screen_type type,
                    const struct dri_config ***driver_configs, bool driver_name_is_inferred,
                    bool has_multibuffer, void *data)
{
    struct dri_screen *screen;

    screen = CALLOC_STRUCT(dri_screen);
    if (!screen)
       return NULL;

    setupLoaderExtensions(screen, loader_extensions);

    screen->loaderPrivate = data;

    screen->fd = fd;
    screen->myNum = scrn;
    screen->type = type;

    /* Option parsing before ->InitScreen(), as some options apply there. */
    driParseOptionInfo(&screen->optionInfo,
                       __dri2ConfigOptions, ARRAY_SIZE(__dri2ConfigOptions));
    driParseConfigFiles(&screen->optionCache, &screen->optionInfo, screen->myNum,
                        "dri2", NULL, NULL, NULL, 0, NULL, 0);

   (void) mtx_init(&screen->opencl_func_mutex, mtx_plain);

   struct pipe_screen *pscreen = NULL;
   switch (type) {
   case DRI_SCREEN_DRI3:
      pscreen = dri2_init_screen(screen, driver_name_is_inferred);
      break;
   case DRI_SCREEN_KOPPER:
      pscreen = kopper_init_screen(screen, driver_name_is_inferred);
      break;
   case DRI_SCREEN_SWRAST:
      pscreen = drisw_init_screen(screen, driver_name_is_inferred);
      break;
   case DRI_SCREEN_KMS_SWRAST:
      pscreen = dri_swrast_kms_init_screen(screen, driver_name_is_inferred);
      break;
   default:
      UNREACHABLE("unknown dri screen type");
   }
   if (pscreen == NULL) {
      dri_destroy_screen(screen);
      return NULL;
   }
   *driver_configs = dri_init_screen(screen, pscreen, has_multibuffer);
   if (*driver_configs == NULL) {
      dri_destroy_screen(screen);
      return NULL;
   }

    struct gl_constants consts = { 0 };
    gl_api api;
    unsigned version;

    api = API_OPENGLES2;
    if (_mesa_override_gl_version_contextless(&consts, &api, &version))
       screen->max_gl_es2_version = version;

    api = API_OPENGL_COMPAT;
    if (_mesa_override_gl_version_contextless(&consts, &api, &version)) {
       screen->max_gl_core_version = version;
       if (api == API_OPENGL_COMPAT)
          screen->max_gl_compat_version = version;
    }

    screen->api_mask = 0;
    if (screen->max_gl_compat_version > 0)
       screen->api_mask |= (1 << __DRI_API_OPENGL);
    if (screen->max_gl_core_version > 0)
       screen->api_mask |= (1 << __DRI_API_OPENGL_CORE);
    if (screen->max_gl_es1_version > 0)
       screen->api_mask |= (1 << __DRI_API_GLES);
    if (screen->max_gl_es2_version > 0)
       screen->api_mask |= (1 << __DRI_API_GLES2);
    if (screen->max_gl_es2_version >= 30)
       screen->api_mask |= (1 << __DRI_API_GLES3);

    return screen;
}

/**
 * Destroy the per-screen private information.
 *
 * \internal
 * This function calls __DriverAPIRec::DestroyScreen on \p screenPrivate, calls
 * drmClose(), and finally frees \p screenPrivate.
 */
void driDestroyScreen(struct dri_screen *psp)
{
    if (psp) {
        /* No interaction with the X-server is possible at this point.  This
         * routine is called after XCloseDisplay, so there is no protocol
         * stream open to the X-server anymore.
         */

        dri_destroy_screen(psp);
    }
}

/*@}*/

/* WARNING: HACK: Local defines to avoid pulling glx.h.
 */
#define GLX_NONE                                                0x8000
#define GLX_DONT_CARE                                           0xFFFFFFFF

#define SIMPLE_CASE(attrib, field) case attrib: *value = config->modes.field; break

/**
 * Return the value of a configuration attribute.  The attribute is
 * indicated by the index.
 */
static int
driGetConfigAttribIndex(const struct dri_config *config,
                        unsigned int index, unsigned int *value)
{
    switch (index + 1) {
    SIMPLE_CASE(__DRI_ATTRIB_BUFFER_SIZE, rgbBits);
    SIMPLE_CASE(__DRI_ATTRIB_RED_SIZE, redBits);
    SIMPLE_CASE(__DRI_ATTRIB_GREEN_SIZE, greenBits);
    SIMPLE_CASE(__DRI_ATTRIB_BLUE_SIZE, blueBits);
    case __DRI_ATTRIB_LEVEL:
    case __DRI_ATTRIB_LUMINANCE_SIZE:
    case __DRI_ATTRIB_AUX_BUFFERS:
        *value = 0;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_ALPHA_SIZE, alphaBits);
    case __DRI_ATTRIB_ALPHA_MASK_SIZE:
        /* I have no idea what this value was ever meant to mean, it's
         * never been set to anything, just say 0.
         */
        *value = 0;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_DEPTH_SIZE, depthBits);
    SIMPLE_CASE(__DRI_ATTRIB_STENCIL_SIZE, stencilBits);
    SIMPLE_CASE(__DRI_ATTRIB_ACCUM_RED_SIZE, accumRedBits);
    SIMPLE_CASE(__DRI_ATTRIB_ACCUM_GREEN_SIZE, accumGreenBits);
    SIMPLE_CASE(__DRI_ATTRIB_ACCUM_BLUE_SIZE, accumBlueBits);
    SIMPLE_CASE(__DRI_ATTRIB_ACCUM_ALPHA_SIZE, accumAlphaBits);
    case __DRI_ATTRIB_SAMPLE_BUFFERS:
        *value = !!config->modes.samples;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_SAMPLES, samples);
    case __DRI_ATTRIB_RENDER_TYPE:
        /* no support for color index mode */
        *value = __DRI_ATTRIB_RGBA_BIT;
        if (config->modes.floatMode)
            *value |= __DRI_ATTRIB_FLOAT_BIT;
        break;
    case __DRI_ATTRIB_CONFIG_CAVEAT:
        if (config->modes.accumRedBits != 0)
            *value = __DRI_ATTRIB_SLOW_BIT;
        else
            *value = 0;
        break;
    case __DRI_ATTRIB_CONFORMANT:
        *value = GL_TRUE;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_DOUBLE_BUFFER, doubleBufferMode);
    SIMPLE_CASE(__DRI_ATTRIB_STEREO, stereoMode);
    case __DRI_ATTRIB_TRANSPARENT_TYPE:
    case __DRI_ATTRIB_TRANSPARENT_INDEX_VALUE: /* horrible bc hack */
        *value = GLX_NONE;
        break;
    case __DRI_ATTRIB_TRANSPARENT_RED_VALUE:
    case __DRI_ATTRIB_TRANSPARENT_GREEN_VALUE:
    case __DRI_ATTRIB_TRANSPARENT_BLUE_VALUE:
    case __DRI_ATTRIB_TRANSPARENT_ALPHA_VALUE:
        *value = GLX_DONT_CARE;
        break;
    case __DRI_ATTRIB_FLOAT_MODE:
        *value = config->modes.floatMode;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_RED_MASK, redMask);
    SIMPLE_CASE(__DRI_ATTRIB_GREEN_MASK, greenMask);
    SIMPLE_CASE(__DRI_ATTRIB_BLUE_MASK, blueMask);
    SIMPLE_CASE(__DRI_ATTRIB_ALPHA_MASK, alphaMask);
    case __DRI_ATTRIB_MAX_PBUFFER_WIDTH:
    case __DRI_ATTRIB_MAX_PBUFFER_HEIGHT:
    case __DRI_ATTRIB_MAX_PBUFFER_PIXELS:
    case __DRI_ATTRIB_OPTIMAL_PBUFFER_WIDTH:
    case __DRI_ATTRIB_OPTIMAL_PBUFFER_HEIGHT:
    case __DRI_ATTRIB_VISUAL_SELECT_GROUP:
        *value = 0;
        break;
    case __DRI_ATTRIB_SWAP_METHOD:
        /* Not supported any more, but we have the __DRI_ATTRIB still defined
         * for the X server's sake, and EGL will expect us to handle it because
         * it iterates all __DRI_ATTRIBs.
         */
        *value = __DRI_ATTRIB_SWAP_UNDEFINED;
        break;
    case __DRI_ATTRIB_MAX_SWAP_INTERVAL:
        *value = INT_MAX;
        break;
    case __DRI_ATTRIB_MIN_SWAP_INTERVAL:
        *value = 0;
        break;
    case __DRI_ATTRIB_BIND_TO_TEXTURE_RGB:
    case __DRI_ATTRIB_BIND_TO_TEXTURE_RGBA:
    case __DRI_ATTRIB_YINVERTED:
        *value = GL_TRUE;
        break;
    case __DRI_ATTRIB_BIND_TO_MIPMAP_TEXTURE:
        *value = GL_FALSE;
        break;
    case __DRI_ATTRIB_BIND_TO_TEXTURE_TARGETS:
        *value = __DRI_ATTRIB_TEXTURE_1D_BIT |
                 __DRI_ATTRIB_TEXTURE_2D_BIT |
                 __DRI_ATTRIB_TEXTURE_RECTANGLE_BIT;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_FRAMEBUFFER_SRGB_CAPABLE, sRGBCapable);
    case __DRI_ATTRIB_MUTABLE_RENDER_BUFFER:
        *value = GL_FALSE;
        break;
    SIMPLE_CASE(__DRI_ATTRIB_RED_SHIFT, redShift);
    SIMPLE_CASE(__DRI_ATTRIB_GREEN_SHIFT, greenShift);
    SIMPLE_CASE(__DRI_ATTRIB_BLUE_SHIFT, blueShift);
    SIMPLE_CASE(__DRI_ATTRIB_ALPHA_SHIFT, alphaShift);
    default:
        /* XXX log an error or smth */
        return GL_FALSE;
    }

    return GL_TRUE;
}

/**
 * Get the value of a configuration attribute.
 * \param attrib  the attribute (one of the _DRI_ATTRIB_x tokens)
 * \param value  returns the attribute's value
 * \return 1 for success, 0 for failure
 */
int
driGetConfigAttrib(const struct dri_config *config,
                   unsigned int attrib, unsigned int *value)
{
    return driGetConfigAttribIndex(config, attrib - 1, value);
}

/**
 * Get a configuration attribute name and value, given an index.
 * \param index  which field of the struct dri_config to query
 * \param attrib  returns the attribute name (one of the _DRI_ATTRIB_x tokens)
 * \param value  returns the attribute's value
 * \return 1 for success, 0 for failure
 */
int
driIndexConfigAttrib(const struct dri_config *config, int index,
                     unsigned int *attrib, unsigned int *value)
{
    if (driGetConfigAttribIndex(config, index, value)) {
        *attrib = index + 1;
        return GL_TRUE;
    }

    return GL_FALSE;
}

static int
validate_context_version(struct dri_screen *screen,
                         int mesa_api,
                         unsigned major_version,
                         unsigned minor_version)
{
   unsigned req_version = 10 * major_version + minor_version;
   unsigned max_version = 0;

   if (major_version == 0 || major_version > 4)
      return __DRI_CTX_ERROR_BAD_API;

   if (mesa_api == API_OPENGL_COMPAT) {
      if ((major_version == 4 && minor_version > 6) ||
          (major_version == 3 && minor_version > 3) ||
          (major_version == 2 && minor_version > 1) ||
          (major_version == 1 && minor_version > 5))
         return __DRI_CTX_ERROR_BAD_API;
      max_version = screen->max_gl_compat_version;
   } else if (mesa_api == API_OPENGLES) {
      if (major_version > 1 || minor_version > 1)
         return __DRI_CTX_ERROR_BAD_API;
      max_version = screen->max_gl_es1_version;
   } else if (mesa_api == API_OPENGLES2) {
      if ((major_version >  3) ||
          (major_version == 3 && minor_version > 2) ||
          (major_version == 2 && minor_version > 0) ||
          (major_version <  2))
         return __DRI_CTX_ERROR_BAD_API;
      max_version = screen->max_gl_es2_version;
   } else if (mesa_api == API_OPENGL_CORE) {
      if ((major_version == 4 && minor_version > 6) ||
          (major_version == 3 && minor_version > 3) ||
          (major_version < 3))
         return __DRI_CTX_ERROR_BAD_API;
      max_version = screen->max_gl_core_version;
   } else {
      return __DRI_CTX_ERROR_BAD_API;
   }

   if (max_version == 0)
      return __DRI_CTX_ERROR_BAD_VERSION;

   if (req_version > max_version)
      return __DRI_CTX_ERROR_BAD_VERSION;

   return __DRI_CTX_ERROR_SUCCESS;
}

/*****************************************************************/
/** \name Context handling functions                             */
/*****************************************************************/
/*@{*/

struct dri_context *
driCreateContextAttribs(struct dri_screen *screen, int api,
                        const struct dri_config *config,
                        struct dri_context *shared,
                        unsigned num_attribs,
                        const uint32_t *attribs,
                        unsigned *error,
                        void *data,
                        bool thread_safe)
{
    const struct gl_config *modes = (config != NULL) ? &config->modes : NULL;
    gl_api mesa_api;
    struct __DriverContextConfig ctx_config;

    ctx_config.major_version = 1;
    ctx_config.minor_version = 0;
    ctx_config.flags = 0;
    ctx_config.attribute_mask = 0;
    ctx_config.priority = __DRI_CTX_PRIORITY_MEDIUM;

    assert((num_attribs == 0) || (attribs != NULL));

    switch (api) {
    case __DRI_API_OPENGL:
        mesa_api = API_OPENGL_COMPAT;
        break;
    case __DRI_API_GLES:
        mesa_api = API_OPENGLES;
        break;
    case __DRI_API_GLES2:
    case __DRI_API_GLES3:
        mesa_api = API_OPENGLES2;
        break;
    case __DRI_API_OPENGL_CORE:
        mesa_api = API_OPENGL_CORE;
        break;
    default:
        *error = __DRI_CTX_ERROR_BAD_API;
        return NULL;
    }

    for (unsigned i = 0; i < num_attribs; i++) {
        switch (attribs[i * 2]) {
        case __DRI_CTX_ATTRIB_MAJOR_VERSION:
            ctx_config.major_version = attribs[i * 2 + 1];
            break;
        case __DRI_CTX_ATTRIB_MINOR_VERSION:
            ctx_config.minor_version = attribs[i * 2 + 1];
            break;
        case __DRI_CTX_ATTRIB_FLAGS:
            ctx_config.flags = attribs[i * 2 + 1];
            break;
        case __DRI_CTX_ATTRIB_RESET_STRATEGY:
            if (attribs[i * 2 + 1] != __DRI_CTX_RESET_NO_NOTIFICATION) {
                ctx_config.attribute_mask |=
                    __DRIVER_CONTEXT_ATTRIB_RESET_STRATEGY;
                ctx_config.reset_strategy = attribs[i * 2 + 1];
            } else {
                ctx_config.attribute_mask &=
                    ~__DRIVER_CONTEXT_ATTRIB_RESET_STRATEGY;
            }
            break;
        case __DRI_CTX_ATTRIB_PRIORITY:
            ctx_config.attribute_mask |= __DRIVER_CONTEXT_ATTRIB_PRIORITY;
            ctx_config.priority = attribs[i * 2 + 1];
            break;
        case __DRI_CTX_ATTRIB_RELEASE_BEHAVIOR:
            if (attribs[i * 2 + 1] != __DRI_CTX_RELEASE_BEHAVIOR_FLUSH) {
                ctx_config.attribute_mask |=
                    __DRIVER_CONTEXT_ATTRIB_RELEASE_BEHAVIOR;
                ctx_config.release_behavior = attribs[i * 2 + 1];
            } else {
                ctx_config.attribute_mask &=
                    ~__DRIVER_CONTEXT_ATTRIB_RELEASE_BEHAVIOR;
            }
            break;
        case __DRI_CTX_ATTRIB_NO_ERROR:
            if (attribs[i * 2 + 1] != 0) {
               ctx_config.attribute_mask |=
                  __DRIVER_CONTEXT_ATTRIB_NO_ERROR;
               ctx_config.no_error = attribs[i * 2 + 1];
            } else {
               ctx_config.attribute_mask &=
                  ~__DRIVER_CONTEXT_ATTRIB_NO_ERROR;
            }
            break;
        case __DRI_CTX_ATTRIB_PROTECTED:
           if (attribs[i * 2 + 1]) {
              ctx_config.attribute_mask |= __DRIVER_CONTEXT_ATTRIB_PROTECTED;
           } else {
              ctx_config.attribute_mask &= ~__DRIVER_CONTEXT_ATTRIB_PROTECTED;
           }
           break;
        default:
            /* We can't create a context that satisfies the requirements of an
             * attribute that we don't understand.  Return failure.
             */
            assert(!"Should not get here.");
            *error = __DRI_CTX_ERROR_UNKNOWN_ATTRIBUTE;
            return NULL;
        }
    }

    /* The specific Mesa driver may not support the GL_ARB_compatibilty
     * extension or the compatibility profile.  In that case, we treat an
     * API_OPENGL_COMPAT 3.1 as API_OPENGL_CORE. We reject API_OPENGL_COMPAT
     * 3.2+ in any case.
     */
    if (mesa_api == API_OPENGL_COMPAT &&
        ctx_config.major_version == 3 && ctx_config.minor_version == 1 &&
        screen->max_gl_compat_version < 31)
       mesa_api = API_OPENGL_CORE;

    /* If the screen supports at maximum OpenGL 3.1, it's free to implement
     * GL_ARB_compatibility or not. However, as OpenGL 3.1 is a corner case
     * on the Core vs Compatiblity thing (it has no Compatibility Profile
     * defined, only GL_ARB_compatibility extension defined), some applications
     * will misbehave without GL_ARB_compatibility, so try hard to support
     * GL_ARB_compatiblity in such case.
     */
    if (mesa_api == API_OPENGL_CORE &&
        ctx_config.major_version == 3 && ctx_config.minor_version == 1 &&
        screen->max_gl_compat_version == 31 &&
        screen->max_gl_core_version == 31)
       mesa_api = API_OPENGL_COMPAT;

    /* The latest version of EGL_KHR_create_context spec says:
     *
     *     "If the EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR flag bit is set in
     *     EGL_CONTEXT_FLAGS_KHR, then a <debug context> will be created.
     *     [...] This bit is supported for OpenGL and OpenGL ES contexts.
     *
     * No other EGL_CONTEXT_OPENGL_*_BIT is legal for an ES context.
     *
     * However, Mesa's EGL layer translates the context attribute
     * EGL_CONTEXT_OPENGL_ROBUST_ACCESS into the context flag
     * __DRI_CTX_FLAG_ROBUST_BUFFER_ACCESS.  That attribute is legal for ES
     * (with EGL 1.5 or EGL_EXT_create_context_robustness) and GL (only with
     * EGL 1.5).
     *
     * From the EGL_EXT_create_context_robustness spec:
     *
     *     This extension is written against the OpenGL ES 2.0 Specification
     *     but can apply to OpenGL ES 1.1 and up.
     *
     * From the EGL 1.5 (2014.08.27) spec, p55:
     *
     *     If the EGL_CONTEXT_OPENGL_ROBUST_ACCESS attribute is set to
     *     EGL_TRUE, a context supporting robust buffer access will be created.
     *     OpenGL contexts must support the GL_ARB_robustness extension, or
     *     equivalent core API functional- ity. OpenGL ES contexts must support
     *     the GL_EXT_robustness extension, or equivalent core API
     *     functionality.
     */
    if (mesa_api != API_OPENGL_COMPAT
        && mesa_api != API_OPENGL_CORE
        && (ctx_config.flags & ~(__DRI_CTX_FLAG_DEBUG |
                                 __DRI_CTX_FLAG_ROBUST_BUFFER_ACCESS))) {
        *error = __DRI_CTX_ERROR_BAD_FLAG;
        return NULL;
    }

    /* There are no forward-compatible contexts before OpenGL 3.0.  The
     * GLX_ARB_create_context spec says:
     *
     *     "Forward-compatible contexts are defined only for OpenGL versions
     *     3.0 and later."
     *
     * Forward-looking contexts are supported by silently converting the
     * requested API to API_OPENGL_CORE.
     *
     * In Mesa, a debug context is the same as a regular context.
     */
    if ((ctx_config.flags & __DRI_CTX_FLAG_FORWARD_COMPATIBLE) != 0) {
       mesa_api = API_OPENGL_CORE;
    }

    const uint32_t allowed_flags = (__DRI_CTX_FLAG_DEBUG
                                    | __DRI_CTX_FLAG_FORWARD_COMPATIBLE
                                    | __DRI_CTX_FLAG_ROBUST_BUFFER_ACCESS
                                    | __DRI_CTX_FLAG_RESET_ISOLATION);
    if (ctx_config.flags & ~allowed_flags) {
        *error = __DRI_CTX_ERROR_UNKNOWN_FLAG;
        return NULL;
    }

    *error = validate_context_version(screen, mesa_api,
                                      ctx_config.major_version,
                                      ctx_config.minor_version);
    if (*error != __DRI_CTX_ERROR_SUCCESS)
       return NULL;

    struct dri_context *ctx = dri_create_context(screen, mesa_api,
                                                 modes, &ctx_config, error,
                                                 shared, data, thread_safe);
    return ctx;
}

static struct dri_context *
driCreateNewContextForAPI(struct dri_screen *screen, int api,
                          const struct dri_config *config,
                          struct dri_context *shared, void *data, bool thread_safe)
{
    unsigned error;

    return driCreateContextAttribs(screen, api, config, shared, 0, NULL,
                                   &error, data, thread_safe);
}

struct dri_context *
driCreateNewContext(struct dri_screen *screen, const struct dri_config *config,
                    struct dri_context *shared, void *data, bool thread_safe)
{
    return driCreateNewContextForAPI(screen, __DRI_API_OPENGL,
                                     config, shared, data, thread_safe);
}

/**
 * Destroy the per-context private information.
 *
 * \internal
 * This function calls __DriverAPIRec::DestroyContext on \p contextPrivate, calls
 * drmDestroyContext(), and finally frees \p contextPrivate.
 */
void
driDestroyContext(struct dri_context *ctx)
{
    if (ctx)
        dri_destroy_context(ctx);
}

int
driCopyContext(struct dri_context *dest, struct dri_context *src, unsigned long mask)
{
    (void) dest;
    (void) src;
    (void) mask;
    return GL_FALSE;
}

/*@}*/


/*****************************************************************/
/** \name Context (un)binding functions                          */
/*****************************************************************/
/*@{*/

/**
 * This function takes both a read buffer and a draw buffer.  This is needed
 * for \c glXMakeCurrentReadSGI or GLX 1.3's \c glXMakeContextCurrent
 * function.
 */
int driBindContext(struct dri_context *ctx,
                   struct dri_drawable *draw,
                   struct dri_drawable *read)
{
   /*
    ** Assume error checking is done properly in glXMakeCurrent before
    ** calling driBindContext.
    */

    if (!ctx)
        return GL_FALSE;

    return dri_make_current(ctx, draw, read);
}

/**
 * Unbind context.
 *
 * \param scrn the screen.
 * \param gc context.
 *
 * \return \c GL_TRUE on success, or \c GL_FALSE on failure.
 *
 * \internal
 * This function calls __DriverAPIRec::UnbindContext, and then decrements
 * dri_drawable::refcount which must be non-zero for a successful
 * return.
 *
 * While casting the opaque private pointers associated with the parameters
 * into their respective real types it also assures they are not \c NULL.
 */
int driUnbindContext(struct dri_context *ctx)
{
    /*
    ** Assume error checking is done properly in glXMakeCurrent before
    ** calling driUnbindContext.
    */

    if (ctx == NULL)
        return GL_FALSE;

    /*
    ** Call dri_unbind_context before checking for valid drawables
    ** to handle surfaceless contexts properly.
    */
    return dri_unbind_context(ctx);
}

/*@}*/

void
driDestroyDrawable(struct dri_drawable *drawable)
{
    dri_put_drawable(drawable);
}

static int
dri2ConfigQueryb(struct dri_screen *screen, const char *var, unsigned char *val)
{
   if (!driCheckOption(&screen->optionCache, var, DRI_BOOL))
      return -1;

   *val = driQueryOptionb(&screen->optionCache, var);

   return 0;
}

static int
dri2ConfigQueryi(struct dri_screen *screen, const char *var, int *val)
{
   if (!driCheckOption(&screen->optionCache, var, DRI_INT) &&
       !driCheckOption(&screen->optionCache, var, DRI_ENUM))
      return -1;

    *val = driQueryOptioni(&screen->optionCache, var);

    return 0;
}

static int
dri2ConfigQueryf(struct dri_screen *screen, const char *var, float *val)
{
   if (!driCheckOption(&screen->optionCache, var, DRI_FLOAT))
      return -1;

    *val = driQueryOptionf(&screen->optionCache, var);

    return 0;
}

static int
dri2ConfigQuerys(struct dri_screen *screen, const char *var, char **val)
{
   if (!driCheckOption(&screen->optionCache, var, DRI_STRING))
      return -1;

    *val = driQueryOptionstr(&screen->optionCache, var);

    return 0;
}


/**
 * \brief the DRI2ConfigQueryExtension configQueryb method
 */
int
dri2GalliumConfigQueryb(struct dri_screen *screen, const char *var,
                        unsigned char *val)
{
   if (!driCheckOption(&screen->dev->option_cache, var, DRI_BOOL))
      return dri2ConfigQueryb(screen, var, val);

   *val = driQueryOptionb(&screen->dev->option_cache, var);

   return 0;
}

/**
 * \brief the DRI2ConfigQueryExtension configQueryi method
 */
int
dri2GalliumConfigQueryi(struct dri_screen *screen, const char *var, int *val)
{
   if (!driCheckOption(&screen->dev->option_cache, var, DRI_INT) &&
       !driCheckOption(&screen->dev->option_cache, var, DRI_ENUM))
      return dri2ConfigQueryi(screen, var, val);

    *val = driQueryOptioni(&screen->dev->option_cache, var);

    return 0;
}

/**
 * \brief the DRI2ConfigQueryExtension configQueryf method
 */
int
dri2GalliumConfigQueryf(struct dri_screen *screen, const char *var, float *val)
{
   if (!driCheckOption(&screen->dev->option_cache, var, DRI_FLOAT))
      return dri2ConfigQueryf(screen, var, val);

    *val = driQueryOptionf(&screen->dev->option_cache, var);

    return 0;
}

/**
 * \brief the DRI2ConfigQueryExtension configQuerys method
 */
int
dri2GalliumConfigQuerys(struct dri_screen *screen, const char *var, char **val)
{
   if (!driCheckOption(&screen->dev->option_cache, var, DRI_STRING))
      return dri2ConfigQuerys(screen, var, val);

    *val = driQueryOptionstr(&screen->dev->option_cache, var);

    return 0;
}

/**
 * \brief the DRI2ConfigQueryExtension struct.
 *
 * We first query the driver option cache. Then the dri2 option cache.
 */
const __DRI2configQueryExtension dri2GalliumConfigQueryExtension = {
   .base = { __DRI2_CONFIG_QUERY, 2 },

   .configQueryb        = dri2GalliumConfigQueryb,
   .configQueryi        = dri2GalliumConfigQueryi,
   .configQueryf        = dri2GalliumConfigQueryf,
   .configQuerys        = dri2GalliumConfigQuerys,
};


unsigned int
driGetAPIMask(struct dri_screen *screen)
{
    return screen->api_mask;
}

/**
 * swrast swapbuffers entrypoint.
 *
 * DRI2 implements this inside the loader with only flushes handled by the
 * driver.
 */
void
driSwapBuffersWithDamage(struct dri_drawable *drawable, int nrects, const int *rects)
{
   assert(drawable->screen->swrast_loader);

   drawable->swap_buffers_with_damage(drawable, nrects, rects);
}

void
driSwapBuffers(struct dri_drawable *drawable)
{
   assert(drawable->screen->swrast_loader);

   drawable->swap_buffers(drawable);
}

int
driSWRastQueryBufferAge(struct dri_drawable *drawable)
{
   return drawable->buffer_age;
}

/*
 * Note: the first match is returned, which is important for formats like
 * __DRI_IMAGE_FORMAT_R8 which maps to both MESA_FORMAT_{R,L}_UNORM8
 */
static const struct {
   uint32_t    image_format;
   GLenum internal_format;
} format_mapping[] = {
   {
      .image_format    = __DRI_IMAGE_FORMAT_RGB565,
      .internal_format =        GL_RGB565,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ARGB1555,
      .internal_format =        GL_RGB5_A1,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR1555,
      .internal_format =        GL_RGB5_A1,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XRGB8888,
      .internal_format =        GL_RGB8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR16161616F,
      .internal_format =        GL_RGBA16F,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XBGR16161616F,
      .internal_format =        GL_RGB16F,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR16161616,
      .internal_format =        GL_RGBA16,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XBGR16161616,
      .internal_format =        GL_RGB16,
   },
   {
      .image_format    = PIPE_FORMAT_R32G32B32A32_FLOAT,
      .internal_format =        GL_RGBA32F,
   },
   {
      .image_format    = PIPE_FORMAT_R32_FLOAT,
      .internal_format =        GL_R32F,
   },
   {
      .image_format    = PIPE_FORMAT_R32G32_FLOAT,
      .internal_format =        GL_RG32F,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ARGB2101010,
      .internal_format =        GL_RGB10_A2,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XRGB2101010,
      .internal_format =        GL_RGB10,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR2101010,
      .internal_format =        GL_RGB10_A2,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XBGR2101010,
      .internal_format =        GL_RGB10,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ARGB8888,
      .internal_format =        GL_RGBA8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR8888,
      .internal_format =        GL_RGBA8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_XBGR8888,
      .internal_format =        GL_RGB8,
   },
#if UTIL_ARCH_BIG_ENDIAN
   {
      .image_format    = PIPE_FORMAT_A8R8G8B8_UNORM,
      .internal_format =        GL_RGBA8,
   },
   {
      .image_format    = PIPE_FORMAT_X8R8G8B8_UNORM,
      .internal_format =        GL_RGB8,
   },
   {
      .image_format    = PIPE_FORMAT_A8B8G8R8_UNORM,
      .internal_format =        GL_RGBA8,
   },
   {
      .image_format    = PIPE_FORMAT_X8B8G8R8_UNORM,
      .internal_format =        GL_RGB8,
   },
#endif
   {
      .image_format    = __DRI_IMAGE_FORMAT_R8,
      .internal_format =        GL_R8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_R8,
      .internal_format =        GL_R8,
   },
#if UTIL_ARCH_LITTLE_ENDIAN
   {
      .image_format    = __DRI_IMAGE_FORMAT_GR88,
      .internal_format =        GL_RG8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_GR88,
      .internal_format =        GL_RG8,
   },
#endif
   {
      .image_format    = __DRI_IMAGE_FORMAT_SABGR8,
      .internal_format =        GL_SRGB8_ALPHA8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_SARGB8,
      .internal_format =        GL_SRGB8_ALPHA8,
   },
   {
      .image_format = __DRI_IMAGE_FORMAT_SXRGB8,
      .internal_format =        GL_SRGB8,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_R16,
      .internal_format =        GL_R16,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_R16,
      .internal_format =        GL_R16,
   },
#if UTIL_ARCH_LITTLE_ENDIAN
   {
      .image_format    = __DRI_IMAGE_FORMAT_GR1616,
      .internal_format =        GL_RG16,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_GR1616,
      .internal_format =        GL_RG16,
   },
#endif
   {
      .image_format    = __DRI_IMAGE_FORMAT_ARGB4444,
      .internal_format =        GL_RGBA4,
   },
   {
      .image_format    = __DRI_IMAGE_FORMAT_ABGR4444,
      .internal_format =        GL_RGBA4,
   },
};

uint32_t
driImageFormatToSizedInternalGLFormat(uint32_t image_format)
{
   for (size_t i = 0; i < ARRAY_SIZE(format_mapping); i++)
      if (format_mapping[i].image_format == image_format)
         return format_mapping[i].internal_format;

   return GL_NONE;
}

static int dri_vblank_mode(struct dri_screen *driScreen)
{
   GLint vblank_mode = DRI_CONF_VBLANK_DEF_INTERVAL_1;
 
   dri2GalliumConfigQueryi(driScreen, "vblank_mode", &vblank_mode);
 
   return vblank_mode;
}
 
int dri_get_initial_swap_interval(struct dri_screen *driScreen)
{
   int vblank_mode = dri_vblank_mode(driScreen);
 
   switch (vblank_mode) {
   case DRI_CONF_VBLANK_NEVER:
   case DRI_CONF_VBLANK_DEF_INTERVAL_0:
      return 0;
   case DRI_CONF_VBLANK_DEF_INTERVAL_1:
   case DRI_CONF_VBLANK_ALWAYS_SYNC:
   default:
      return 1;
   }
}
 
bool dri_valid_swap_interval(struct dri_screen *driScreen, int interval)
{
   int vblank_mode = dri_vblank_mode(driScreen);
 
   switch (vblank_mode) {
   case DRI_CONF_VBLANK_NEVER:
      if (interval != 0)
         return false;
      break;
   case DRI_CONF_VBLANK_ALWAYS_SYNC:
      if (interval <= 0)
         return false;
      break;
   default:
      break;
   }
 
   return true;
}

struct pipe_screen *
dri_get_pipe_screen(struct dri_screen *screen)
{
   return screen->base.screen;
}

char *
driGetDriInfoXML(const char* driverName)
{
   return pipe_loader_get_driinfo_xml(driverName);
}

bool
dri_get_drm_device_info(const char *device_name, uint8_t *device_uuid, uint8_t *driver_uuid,
                        char **vendor_name, char **renderer_name, char **driver_name)
{
#ifdef HAVE_LIBDRM
   struct pipe_loader_device *pldev;
   struct pipe_screen *pscreen;
   int fd;

   fd = loader_open_device(device_name);
   if (fd == -1) {
      return false;
   }
   if (!pipe_loader_drm_probe_fd(&pldev, fd, false)) {
      close(fd);
      return false;
   }
   pscreen = pipe_loader_create_screen(pldev, true);
   if (!pscreen) {
      pipe_loader_release(&pldev, 1);
      close(fd);
      return false;
   }

   if (pscreen->get_device_uuid)
      pscreen->get_device_uuid(pscreen, (char *)device_uuid);

   if (pscreen->get_driver_uuid)
      pscreen->get_driver_uuid(pscreen, (char *)driver_uuid);

   if (pscreen->get_device_vendor)
      *vendor_name = strdup(pscreen->get_device_vendor(pscreen));

   if (pscreen->get_name)
      *renderer_name = strdup(pscreen->get_name(pscreen));

   *driver_name = loader_get_driver_for_fd(fd);

   pscreen->destroy(pscreen);
   pipe_loader_release(&pldev, 1);
   close(fd);

   return true;
#else
   return false;
#endif
}
