/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifdef MOZ_WIDGET_GTK
#include <gdk/gdk.h>
#include <gdk/gdkx.h>
#define GET_NATIVE_WINDOW(aWidget) GDK_WINDOW_XID((GdkWindow *) aWidget->GetNativeData(NS_NATIVE_WINDOW))
#elif defined(MOZ_WIDGET_QT)
#define GET_NATIVE_WINDOW(aWidget) (Window)(aWidget->GetNativeData(NS_NATIVE_SHAREABLE_WINDOW))
#endif

#include <X11/Xlib.h>
#include <X11/Xutil.h>

#include "mozilla/MathAlgorithms.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/X11Util.h"

#include "prenv.h"
#include "GLContextProvider.h"
#include "GLLibraryLoader.h"
#include "nsDebug.h"
#include "nsIWidget.h"
#include "GLXLibrary.h"
#include "gfxXlibSurface.h"
#include "gfxContext.h"
#include "gfxImageSurface.h"
#include "gfxPlatform.h"
#include "GLContextGLX.h"
#include "gfxUtils.h"
#include "gfx2DGlue.h"

#include "gfxCrashReporterUtils.h"

#ifdef MOZ_WIDGET_GTK
#include "gfxPlatformGtk.h"
#endif

using namespace mozilla::gfx;

namespace mozilla {
namespace gl {

GLXLibrary sGLXLibrary;

// Check that we have at least version aMajor.aMinor .
bool
GLXLibrary::GLXVersionCheck(int aMajor, int aMinor)
{
    return aMajor < mGLXMajorVersion ||
           (aMajor == mGLXMajorVersion && aMinor <= mGLXMinorVersion);
}

static inline bool
HasExtension(const char* aExtensions, const char* aRequiredExtension)
{
    return GLContext::ListHasExtension(
        reinterpret_cast<const GLubyte*>(aExtensions), aRequiredExtension);
}

bool
GLXLibrary::EnsureInitialized()
{
    if (mInitialized) {
        return true;
    }

    // Don't repeatedly try to initialize.
    if (mTriedInitializing) {
        return false;
    }
    mTriedInitializing = true;

    // Force enabling s3 texture compression. (Bug 774134)
    PR_SetEnv("force_s3tc_enable=true");

    if (!mOGLLibrary) {
        const char* libGLfilename = nullptr;
        bool forceFeatureReport = false;

        // see e.g. bug 608526: it is intrinsically interesting to know whether we have dynamically linked to libGL.so.1
        // because at least the NVIDIA implementation requires an executable stack, which causes mprotect calls,
        // which trigger glibc bug http://sourceware.org/bugzilla/show_bug.cgi?id=12225
#ifdef __OpenBSD__
        libGLfilename = "libGL.so";
#else
        libGLfilename = "libGL.so.1";
#endif

        ScopedGfxFeatureReporter reporter(libGLfilename, forceFeatureReport);
        mOGLLibrary = PR_LoadLibrary(libGLfilename);
        if (!mOGLLibrary) {
            NS_WARNING("Couldn't load OpenGL shared library.");
            return false;
        }
        reporter.SetSuccessful();
    }

    if (PR_GetEnv("MOZ_GLX_DEBUG")) {
        mDebug = true;
    }

    GLLibraryLoader::SymLoadStruct symbols[] = {
        /* functions that were in GLX 1.0 */
        { (PRFuncPtr*) &xDestroyContextInternal, { "glXDestroyContext", nullptr } },
        { (PRFuncPtr*) &xMakeCurrentInternal, { "glXMakeCurrent", nullptr } },
        { (PRFuncPtr*) &xSwapBuffersInternal, { "glXSwapBuffers", nullptr } },
        { (PRFuncPtr*) &xQueryVersionInternal, { "glXQueryVersion", nullptr } },
        { (PRFuncPtr*) &xGetCurrentContextInternal, { "glXGetCurrentContext", nullptr } },
        { (PRFuncPtr*) &xWaitGLInternal, { "glXWaitGL", nullptr } },
        { (PRFuncPtr*) &xWaitXInternal, { "glXWaitX", nullptr } },
        /* functions introduced in GLX 1.1 */
        { (PRFuncPtr*) &xQueryExtensionsStringInternal, { "glXQueryExtensionsString", nullptr } },
        { (PRFuncPtr*) &xGetClientStringInternal, { "glXGetClientString", nullptr } },
        { (PRFuncPtr*) &xQueryServerStringInternal, { "glXQueryServerString", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols13[] = {
        /* functions introduced in GLX 1.3 */
        { (PRFuncPtr*) &xChooseFBConfigInternal, { "glXChooseFBConfig", nullptr } },
        { (PRFuncPtr*) &xGetFBConfigAttribInternal, { "glXGetFBConfigAttrib", nullptr } },
        // WARNING: xGetFBConfigs not set in symbols13_ext
        { (PRFuncPtr*) &xGetFBConfigsInternal, { "glXGetFBConfigs", nullptr } },
        // WARNING: symbols13_ext sets xCreateGLXPixmapWithConfig instead
        { (PRFuncPtr*) &xCreatePixmapInternal, { "glXCreatePixmap", nullptr } },
        { (PRFuncPtr*) &xDestroyPixmapInternal, { "glXDestroyPixmap", nullptr } },
        { (PRFuncPtr*) &xCreateNewContextInternal, { "glXCreateNewContext", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols13_ext[] = {
        /* extension equivalents for functions introduced in GLX 1.3 */
        // GLX_SGIX_fbconfig extension
        { (PRFuncPtr*) &xChooseFBConfigInternal, { "glXChooseFBConfigSGIX", nullptr } },
        { (PRFuncPtr*) &xGetFBConfigAttribInternal, { "glXGetFBConfigAttribSGIX", nullptr } },
        // WARNING: no xGetFBConfigs equivalent in extensions
        // WARNING: different from symbols13:
        { (PRFuncPtr*) &xCreateGLXPixmapWithConfigInternal, { "glXCreateGLXPixmapWithConfigSGIX", nullptr } },
        { (PRFuncPtr*) &xDestroyPixmapInternal, { "glXDestroyGLXPixmap", nullptr } }, // not from ext
        { (PRFuncPtr*) &xCreateNewContextInternal, { "glXCreateContextWithConfigSGIX", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols14[] = {
        /* functions introduced in GLX 1.4 */
        { (PRFuncPtr*) &xGetProcAddressInternal, { "glXGetProcAddress", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols14_ext[] = {
        /* extension equivalents for functions introduced in GLX 1.4 */
        // GLX_ARB_get_proc_address extension
        { (PRFuncPtr*) &xGetProcAddressInternal, { "glXGetProcAddressARB", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols_texturefrompixmap[] = {
        { (PRFuncPtr*) &xBindTexImageInternal, { "glXBindTexImageEXT", nullptr } },
        { (PRFuncPtr*) &xReleaseTexImageInternal, { "glXReleaseTexImageEXT", nullptr } },
        { nullptr, { nullptr } }
    };

    GLLibraryLoader::SymLoadStruct symbols_robustness[] = {
        { (PRFuncPtr*) &xCreateContextAttribsInternal, { "glXCreateContextAttribsARB", nullptr } },
        { nullptr, { nullptr } }
    };

    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &symbols[0])) {
        NS_WARNING("Couldn't find required entry point in OpenGL shared library");
        return false;
    }

    Display *display = DefaultXDisplay();
    int screen = DefaultScreen(display);

    if (!xQueryVersion(display, &mGLXMajorVersion, &mGLXMinorVersion)) {
        mGLXMajorVersion = 0;
        mGLXMinorVersion = 0;
        return false;
    }

    if (!GLXVersionCheck(1, 1))
        // Not possible to query for extensions.
        return false;

    const char *clientVendor = xGetClientString(display, LOCAL_GLX_VENDOR);
    const char *serverVendor = xQueryServerString(display, screen, LOCAL_GLX_VENDOR);
    const char *extensionsStr = xQueryExtensionsString(display, screen);

    GLLibraryLoader::SymLoadStruct *sym13;
    if (!GLXVersionCheck(1, 3)) {
        // Even if we don't have 1.3, we might have equivalent extensions
        // (as on the Intel X server).
        if (!HasExtension(extensionsStr, "GLX_SGIX_fbconfig")) {
            return false;
        }
        sym13 = symbols13_ext;
    } else {
        sym13 = symbols13;
    }
    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, sym13)) {
        NS_WARNING("Couldn't find required entry point in OpenGL shared library");
        return false;
    }

    GLLibraryLoader::SymLoadStruct *sym14;
    if (!GLXVersionCheck(1, 4)) {
        // Even if we don't have 1.4, we might have equivalent extensions
        // (as on the Intel X server).
        if (!HasExtension(extensionsStr, "GLX_ARB_get_proc_address")) {
            return false;
        }
        sym14 = symbols14_ext;
    } else {
        sym14 = symbols14;
    }
    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, sym14)) {
        NS_WARNING("Couldn't find required entry point in OpenGL shared library");
        return false;
    }

    if (HasExtension(extensionsStr, "GLX_EXT_texture_from_pixmap") &&
        GLLibraryLoader::LoadSymbols(mOGLLibrary, symbols_texturefrompixmap,
                                         (GLLibraryLoader::PlatformLookupFunction)&xGetProcAddress))
    {
#ifdef MOZ_WIDGET_GTK
        mUseTextureFromPixmap = gfxPlatformGtk::GetPlatform()->UseXRender();
#else
        mUseTextureFromPixmap = true;
#endif
    } else {
        mUseTextureFromPixmap = false;
        NS_WARNING("Texture from pixmap disabled");
    }

    if (HasExtension(extensionsStr, "GLX_ARB_create_context_robustness") &&
        GLLibraryLoader::LoadSymbols(mOGLLibrary, symbols_robustness)) {
        mHasRobustness = true;
    }

    mIsATI = serverVendor && DoesStringMatch(serverVendor, "ATI");
    mIsNVIDIA = serverVendor && DoesStringMatch(serverVendor, "NVIDIA Corporation");
    mClientIsMesa = clientVendor && DoesStringMatch(clientVendor, "Mesa");

    mInitialized = true;

    return true;
}

bool
GLXLibrary::SupportsTextureFromPixmap(gfxASurface* aSurface)
{
    if (!EnsureInitialized()) {
        return false;
    }

    if (aSurface->GetType() != gfxSurfaceType::Xlib || !mUseTextureFromPixmap) {
        return false;
    }

    return true;
}

GLXPixmap
GLXLibrary::CreatePixmap(gfxASurface* aSurface)
{
    if (!SupportsTextureFromPixmap(aSurface)) {
        return None;
    }

    gfxXlibSurface *xs = static_cast<gfxXlibSurface*>(aSurface);
    const XRenderPictFormat *format = xs->XRenderFormat();
    if (!format || format->type != PictTypeDirect) {
        return None;
    }
    const XRenderDirectFormat& direct = format->direct;
    int alphaSize = FloorLog2(direct.alphaMask + 1);
    NS_ASSERTION((1 << alphaSize) - 1 == direct.alphaMask,
                 "Unexpected render format with non-adjacent alpha bits");

    int attribs[] = { LOCAL_GLX_DOUBLEBUFFER, False,
                      LOCAL_GLX_DRAWABLE_TYPE, LOCAL_GLX_PIXMAP_BIT,
                      LOCAL_GLX_ALPHA_SIZE, alphaSize,
                      (alphaSize ? LOCAL_GLX_BIND_TO_TEXTURE_RGBA_EXT
                       : LOCAL_GLX_BIND_TO_TEXTURE_RGB_EXT), True,
                      LOCAL_GLX_RENDER_TYPE, LOCAL_GLX_RGBA_BIT,
                      None };

    int numConfigs = 0;
    Display *display = xs->XDisplay();
    int xscreen = DefaultScreen(display);

    ScopedXFree<GLXFBConfig> cfgs(xChooseFBConfig(display,
                                                  xscreen,
                                                  attribs,
                                                  &numConfigs));

    // Find an fbconfig that matches the pixel format used on the Pixmap.
    int matchIndex = -1;
    unsigned long redMask =
        static_cast<unsigned long>(direct.redMask) << direct.red;
    unsigned long greenMask =
        static_cast<unsigned long>(direct.greenMask) << direct.green;
    unsigned long blueMask =
        static_cast<unsigned long>(direct.blueMask) << direct.blue;
    // This is true if the Pixmap has bits for alpha or unused bits.
    bool haveNonColorBits =
        ~(redMask | greenMask | blueMask) != -1UL << format->depth;

    for (int i = 0; i < numConfigs; i++) {
        int id = None;
        sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i], LOCAL_GLX_VISUAL_ID, &id);
        Visual *visual;
        int depth;
        FindVisualAndDepth(display, id, &visual, &depth);
        if (!visual ||
            visual->c_class != TrueColor ||
            visual->red_mask != redMask ||
            visual->green_mask != greenMask ||
            visual->blue_mask != blueMask ) {
            continue;
        }

        // Historically Xlib Visuals did not try to represent an alpha channel
        // and there was no means to use an alpha channel on a Pixmap.  The
        // Xlib Visual from the fbconfig was not intended to have any
        // information about alpha bits.
        //
        // Since then, RENDER has added formats for 32 bit depth Pixmaps.
        // Some of these formats have bits for alpha and some have unused
        // bits.
        //
        // Then the Composite extension added a 32 bit depth Visual intended
        // for Windows with an alpha channel, so bits not in the visual color
        // masks were expected to be treated as alpha bits.
        //
        // Usually GLX counts only color bits in the Visual depth, but the
        // depth of Composite's ARGB Visual includes alpha bits.  However,
        // bits not in the color masks are not necessarily alpha bits because
        // sometimes (NVIDIA) 32 bit Visuals are added for fbconfigs with 32
        // bit BUFFER_SIZE but zero alpha bits and 24 color bits (NVIDIA
        // again).
        //
        // This checks that the depth matches in one of the two ways.
        // NVIDIA now forces format->depth == depth so only the first way
        // is checked for NVIDIA
        if (depth != format->depth &&
            (mIsNVIDIA || depth != format->depth - alphaSize) ) {
            continue;
        }

        // If all bits of the Pixmap are color bits and the Pixmap depth
        // matches the depth of the fbconfig visual, then we can assume that
        // the driver will do whatever is necessary to ensure that any
        // GLXPixmap alpha bits are treated as set.  We can skip the
        // ALPHA_SIZE check in this situation.  We need to skip this check for
        // situations (ATI) where there are no fbconfigs without alpha bits.
        //
        // glXChooseFBConfig should prefer configs with smaller
        // LOCAL_GLX_BUFFER_SIZE, so we should still get zero alpha bits if
        // available, except perhaps with NVIDIA drivers where buffer size is
        // not the specified sum of the component sizes.
        if (haveNonColorBits) {
            // There are bits in the Pixmap format that haven't been matched
            // against the fbconfig visual.  These bits could either represent
            // alpha or be unused, so just check that the number of alpha bits
            // matches.
            int size = 0;
            sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i],
                                           LOCAL_GLX_ALPHA_SIZE, &size);
            if (size != alphaSize) {
                continue;
            }
        }

        matchIndex = i;
        break;
    }
    if (matchIndex == -1) {
        // GLX can't handle A8 surfaces, so this is not really unexpected. The
        // caller should deal with this situation.
        NS_WARN_IF_FALSE(format->depth == 8,
                         "[GLX] Couldn't find a FBConfig matching Pixmap format");
        return None;
    }

    int pixmapAttribs[] = { LOCAL_GLX_TEXTURE_TARGET_EXT, LOCAL_GLX_TEXTURE_2D_EXT,
                            LOCAL_GLX_TEXTURE_FORMAT_EXT,
                            (alphaSize ? LOCAL_GLX_TEXTURE_FORMAT_RGBA_EXT
                             : LOCAL_GLX_TEXTURE_FORMAT_RGB_EXT),
                            None};

    GLXPixmap glxpixmap = xCreatePixmap(display,
                                        cfgs[matchIndex],
                                        xs->XDrawable(),
                                        pixmapAttribs);

    return glxpixmap;
}

void
GLXLibrary::DestroyPixmap(Display* aDisplay, GLXPixmap aPixmap)
{
    if (!mUseTextureFromPixmap) {
        return;
    }

    xDestroyPixmap(aDisplay, aPixmap);
}

void
GLXLibrary::BindTexImage(Display* aDisplay, GLXPixmap aPixmap)
{
    if (!mUseTextureFromPixmap) {
        return;
    }

    // Make sure all X drawing to the surface has finished before binding to a texture.
    if (mClientIsMesa) {
        // Using XSync instead of Mesa's glXWaitX, because its glxWaitX is a
        // noop when direct rendering unless the current drawable is a
        // single-buffer window.
        FinishX(aDisplay);
    } else {
        xWaitX();
    }
    xBindTexImage(aDisplay, aPixmap, LOCAL_GLX_FRONT_LEFT_EXT, nullptr);
}

void
GLXLibrary::ReleaseTexImage(Display* aDisplay, GLXPixmap aPixmap)
{
    if (!mUseTextureFromPixmap) {
        return;
    }

    xReleaseTexImage(aDisplay, aPixmap, LOCAL_GLX_FRONT_LEFT_EXT);
}

void
GLXLibrary::UpdateTexImage(Display* aDisplay, GLXPixmap aPixmap)
{
    // NVIDIA drivers don't require a rebind of the pixmap in order
    // to display an updated image, and it's faster not to do it.
    if (mIsNVIDIA) {
        xWaitX();
        return;
    }

    ReleaseTexImage(aDisplay, aPixmap);
    BindTexImage(aDisplay, aPixmap);
}

#ifdef DEBUG

static int (*sOldErrorHandler)(Display *, XErrorEvent *);
ScopedXErrorHandler::ErrorEvent sErrorEvent;
static int GLXErrorHandler(Display *display, XErrorEvent *ev)
{
    if (!sErrorEvent.mError.error_code) {
        sErrorEvent.mError = *ev;
    }
    return 0;
}

void
GLXLibrary::BeforeGLXCall()
{
    if (mDebug) {
        sOldErrorHandler = XSetErrorHandler(GLXErrorHandler);
    }
}

void
GLXLibrary::AfterGLXCall()
{
    if (mDebug) {
        FinishX(DefaultXDisplay());
        if (sErrorEvent.mError.error_code) {
            char buffer[2048];
            XGetErrorText(DefaultXDisplay(), sErrorEvent.mError.error_code, buffer, sizeof(buffer));
            printf_stderr("X ERROR: %s (%i) - Request: %i.%i, Serial: %i",
                          buffer,
                          sErrorEvent.mError.error_code,
                          sErrorEvent.mError.request_code,
                          sErrorEvent.mError.minor_code,
                          sErrorEvent.mError.serial);
            NS_ABORT();
        }
        XSetErrorHandler(sOldErrorHandler);
    }
}

#define BEFORE_GLX_CALL do {           \
    sGLXLibrary.BeforeGLXCall();       \
} while (0)

#define AFTER_GLX_CALL do {            \
    sGLXLibrary.AfterGLXCall();        \
} while (0)

#else

#define BEFORE_GLX_CALL do { } while(0)
#define AFTER_GLX_CALL do { } while(0)

#endif

void
GLXLibrary::xDestroyContext(Display* display, GLXContext context)
{
    BEFORE_GLX_CALL;
    xDestroyContextInternal(display, context);
    AFTER_GLX_CALL;
}

Bool
GLXLibrary::xMakeCurrent(Display* display,
                         GLXDrawable drawable,
                         GLXContext context)
{
    BEFORE_GLX_CALL;
    Bool result = xMakeCurrentInternal(display, drawable, context);
    AFTER_GLX_CALL;
    return result;
}

GLXContext
GLXLibrary::xGetCurrentContext()
{
    BEFORE_GLX_CALL;
    GLXContext result = xGetCurrentContextInternal();
    AFTER_GLX_CALL;
    return result;
}

/* static */ void*
GLXLibrary::xGetProcAddress(const char *procName)
{
    BEFORE_GLX_CALL;
    void* result = sGLXLibrary.xGetProcAddressInternal(procName);
    AFTER_GLX_CALL;
    return result;
}

GLXFBConfig*
GLXLibrary::xChooseFBConfig(Display* display,
                            int screen,
                            const int *attrib_list,
                            int *nelements)
{
    BEFORE_GLX_CALL;
    GLXFBConfig* result = xChooseFBConfigInternal(display, screen, attrib_list, nelements);
    AFTER_GLX_CALL;
    return result;
}

GLXFBConfig*
GLXLibrary::xGetFBConfigs(Display* display,
                          int screen,
                          int *nelements)
{
    BEFORE_GLX_CALL;
    GLXFBConfig* result = xGetFBConfigsInternal(display, screen, nelements);
    AFTER_GLX_CALL;
    return result;
}

GLXContext
GLXLibrary::xCreateNewContext(Display* display,
                              GLXFBConfig config,
                              int render_type,
                              GLXContext share_list,
                              Bool direct)
{
    BEFORE_GLX_CALL;
    GLXContext result = xCreateNewContextInternal(display, config,
                                                  render_type,
                                                  share_list, direct);
    AFTER_GLX_CALL;
    return result;
}

int
GLXLibrary::xGetFBConfigAttrib(Display *display,
                               GLXFBConfig config,
                               int attribute,
                               int *value)
{
    BEFORE_GLX_CALL;
    int result = xGetFBConfigAttribInternal(display, config,
                                            attribute, value);
    AFTER_GLX_CALL;
    return result;
}

void
GLXLibrary::xSwapBuffers(Display *display, GLXDrawable drawable)
{
    BEFORE_GLX_CALL;
    xSwapBuffersInternal(display, drawable);
    AFTER_GLX_CALL;
}

const char *
GLXLibrary::xQueryExtensionsString(Display *display,
                                   int screen)
{
    BEFORE_GLX_CALL;
    const char *result = xQueryExtensionsStringInternal(display, screen);
    AFTER_GLX_CALL;
    return result;
}

const char *
GLXLibrary::xGetClientString(Display *display,
                             int screen)
{
    BEFORE_GLX_CALL;
    const char *result = xGetClientStringInternal(display, screen);
    AFTER_GLX_CALL;
    return result;
}

const char *
GLXLibrary::xQueryServerString(Display *display,
                               int screen, int name)
{
    BEFORE_GLX_CALL;
    const char *result = xQueryServerStringInternal(display, screen, name);
    AFTER_GLX_CALL;
    return result;
}

GLXPixmap
GLXLibrary::xCreatePixmap(Display *display,
                          GLXFBConfig config,
                          Pixmap pixmap,
                          const int *attrib_list)
{
    BEFORE_GLX_CALL;
    GLXPixmap result = xCreatePixmapInternal(display, config,
                                             pixmap, attrib_list);
    AFTER_GLX_CALL;
    return result;
}

GLXPixmap
GLXLibrary::xCreateGLXPixmapWithConfig(Display *display,
                                       GLXFBConfig config,
                                       Pixmap pixmap)
{
    BEFORE_GLX_CALL;
    GLXPixmap result = xCreateGLXPixmapWithConfigInternal(display, config, pixmap);
    AFTER_GLX_CALL;
    return result;
}

void
GLXLibrary::xDestroyPixmap(Display *display, GLXPixmap pixmap)
{
    BEFORE_GLX_CALL;
    xDestroyPixmapInternal(display, pixmap);
    AFTER_GLX_CALL;
}

Bool
GLXLibrary::xQueryVersion(Display *display,
                          int *major,
                          int *minor)
{
    BEFORE_GLX_CALL;
    Bool result = xQueryVersionInternal(display, major, minor);
    AFTER_GLX_CALL;
    return result;
}

void
GLXLibrary::xBindTexImage(Display *display,
                          GLXDrawable drawable,
                          int buffer,
                          const int *attrib_list)
{
    BEFORE_GLX_CALL;
    xBindTexImageInternal(display, drawable, buffer, attrib_list);
    AFTER_GLX_CALL;
}

void
GLXLibrary::xReleaseTexImage(Display *display,
                             GLXDrawable drawable,
                             int buffer)
{
    BEFORE_GLX_CALL;
    xReleaseTexImageInternal(display, drawable, buffer);
    AFTER_GLX_CALL;
}

void
GLXLibrary::xWaitGL()
{
    BEFORE_GLX_CALL;
    xWaitGLInternal();
    AFTER_GLX_CALL;
}

void
GLXLibrary::xWaitX()
{
    BEFORE_GLX_CALL;
    xWaitXInternal();
    AFTER_GLX_CALL;
}

GLXContext
GLXLibrary::xCreateContextAttribs(Display* display,
                                  GLXFBConfig config,
                                  GLXContext share_list,
                                  Bool direct,
                                  const int* attrib_list)
{
    BEFORE_GLX_CALL;
    GLXContext result = xCreateContextAttribsInternal(display,
                                                      config,
                                                      share_list,
                                                      direct,
                                                      attrib_list);
    AFTER_GLX_CALL;
    return result;
}

already_AddRefed<GLContextGLX>
GLContextGLX::CreateGLContext(
                  const SurfaceCaps& caps,
                  GLContextGLX* shareContext,
                  bool isOffscreen,
                  Display* display,
                  GLXDrawable drawable,
                  GLXFBConfig cfg,
                  bool deleteDrawable,
                  gfxXlibSurface* pixmap)
{
    GLXLibrary& glx = sGLXLibrary;

    int db = 0;
    int err = glx.xGetFBConfigAttrib(display, cfg,
                                      LOCAL_GLX_DOUBLEBUFFER, &db);
    if (LOCAL_GLX_BAD_ATTRIBUTE != err) {
#ifdef DEBUG
        if (DebugMode()) {
            printf("[GLX] FBConfig is %sdouble-buffered\n", db ? "" : "not ");
        }
#endif
    }

    GLXContext context;
    nsRefPtr<GLContextGLX> glContext;
    bool error;

    ScopedXErrorHandler xErrorHandler;

TRY_AGAIN_NO_SHARING:

    error = false;

    GLXContext glxContext = shareContext ? shareContext->mContext : nullptr;
    if (glx.HasRobustness()) {
        int attrib_list[] = {
            LOCAL_GL_CONTEXT_FLAGS_ARB, LOCAL_GL_CONTEXT_ROBUST_ACCESS_BIT_ARB,
            LOCAL_GL_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB, LOCAL_GL_LOSE_CONTEXT_ON_RESET_ARB,
            0,
        };

        context = glx.xCreateContextAttribs(
            display,
            cfg,
            glxContext,
            True,
            attrib_list);
    } else {
        context = glx.xCreateNewContext(
            display,
            cfg,
            LOCAL_GLX_RGBA_TYPE,
            glxContext,
            True);
    }

    if (context) {
        glContext = new GLContextGLX(caps,
                                      shareContext,
                                      isOffscreen,
                                      display,
                                      drawable,
                                      context,
                                      deleteDrawable,
                                      db,
                                      pixmap);
        if (!glContext->Init())
            error = true;
    } else {
        error = true;
    }

    error |= xErrorHandler.SyncAndGetError(display);

    if (error) {
        if (shareContext) {
            shareContext = nullptr;
            goto TRY_AGAIN_NO_SHARING;
        }

        NS_WARNING("Failed to create GLXContext!");
        glContext = nullptr; // note: this must be done while the graceful X error handler is set,
                            // because glxMakeCurrent can give a GLXBadDrawable error
    }

    return glContext.forget();
}

GLContextGLX::~GLContextGLX()
{
    MarkDestroyed();

    // see bug 659842 comment 76
#ifdef DEBUG
    bool success =
#endif
    mGLX->xMakeCurrent(mDisplay, None, nullptr);
    NS_ABORT_IF_FALSE(success,
        "glXMakeCurrent failed to release GL context before we call glXDestroyContext!");

    mGLX->xDestroyContext(mDisplay, mContext);

    if (mDeleteDrawable) {
        mGLX->xDestroyPixmap(mDisplay, mDrawable);
    }
}

bool
GLContextGLX::Init()
{
    SetupLookupFunction();
    if (!InitWithPrefix("gl", true)) {
        return false;
    }

    if (!IsExtensionSupported(EXT_framebuffer_object))
        return false;

    return true;
}

bool
GLContextGLX::MakeCurrentImpl(bool aForce)
{
    bool succeeded = true;

    // With the ATI FGLRX driver, glxMakeCurrent is very slow even when the context doesn't change.
    // (This is not the case with other drivers such as NVIDIA).
    // So avoid calling it more than necessary. Since GLX documentation says that:
    //     "glXGetCurrentContext returns client-side information.
    //      It does not make a round trip to the server."
    // I assume that it's not worth using our own TLS slot here.
    if (aForce || mGLX->xGetCurrentContext() != mContext) {
        succeeded = mGLX->xMakeCurrent(mDisplay, mDrawable, mContext);
        NS_ASSERTION(succeeded, "Failed to make GL context current!");
    }

    return succeeded;
}

bool
GLContextGLX::IsCurrent() {
    return mGLX->xGetCurrentContext() == mContext;
}

bool
GLContextGLX::SetupLookupFunction()
{
    mLookupFunc = (PlatformLookupFunction)&GLXLibrary::xGetProcAddress;
    return true;
}

bool
GLContextGLX::IsDoubleBuffered() const
{
    return mDoubleBuffered;
}

bool
GLContextGLX::SupportsRobustness() const
{
    return mGLX->HasRobustness();
}

bool
GLContextGLX::SwapBuffers()
{
    if (!mDoubleBuffered)
        return false;
    mGLX->xSwapBuffers(mDisplay, mDrawable);
    mGLX->xWaitGL();
    return true;
}

GLContextGLX::GLContextGLX(
                  const SurfaceCaps& caps,
                  GLContext* shareContext,
                  bool isOffscreen,
                  Display *aDisplay,
                  GLXDrawable aDrawable,
                  GLXContext aContext,
                  bool aDeleteDrawable,
                  bool aDoubleBuffered,
                  gfxXlibSurface *aPixmap)
    : GLContext(caps, shareContext, isOffscreen),//aDeleteDrawable ? true : false, aShareContext, ),
      mContext(aContext),
      mDisplay(aDisplay),
      mDrawable(aDrawable),
      mDeleteDrawable(aDeleteDrawable),
      mDoubleBuffered(aDoubleBuffered),
      mGLX(&sGLXLibrary),
      mPixmap(aPixmap)
{
    MOZ_ASSERT(mGLX);
    // See 899855
    SetProfileVersion(ContextProfile::OpenGLCompatibility, 200);
}


static GLContextGLX *
GetGlobalContextGLX()
{
    return static_cast<GLContextGLX*>(GLContextProviderGLX::GetGlobalContext());
}

static bool
AreCompatibleVisuals(Visual *one, Visual *two)
{
    if (one->c_class != two->c_class) {
        return false;
    }

    if (one->red_mask != two->red_mask ||
        one->green_mask != two->green_mask ||
        one->blue_mask != two->blue_mask) {
        return false;
    }

    if (one->bits_per_rgb != two->bits_per_rgb) {
        return false;
    }

    return true;
}

already_AddRefed<GLContext>
GLContextProviderGLX::CreateForWindow(nsIWidget *aWidget)
{
    if (!sGLXLibrary.EnsureInitialized()) {
        return nullptr;
    }

    // Currently, we take whatever Visual the window already has, and
    // try to create an fbconfig for that visual.  This isn't
    // necessarily what we want in the long run; an fbconfig may not
    // be available for the existing visual, or if it is, the GL
    // performance might be suboptimal.  But using the existing visual
    // is a relatively safe intermediate step.

    Display *display = (Display*)aWidget->GetNativeData(NS_NATIVE_DISPLAY);
    int xscreen = DefaultScreen(display);
    Window window = GET_NATIVE_WINDOW(aWidget);

    int numConfigs;
    ScopedXFree<GLXFBConfig> cfgs;
    if (sGLXLibrary.IsATI() ||
        !sGLXLibrary.GLXVersionCheck(1, 3)) {
        const int attribs[] = {
            LOCAL_GLX_DOUBLEBUFFER, False,
            0
        };
        cfgs = sGLXLibrary.xChooseFBConfig(display,
                                           xscreen,
                                           attribs,
                                           &numConfigs);
    } else {
        cfgs = sGLXLibrary.xGetFBConfigs(display,
                                         xscreen,
                                         &numConfigs);
    }

    if (!cfgs) {
        NS_WARNING("[GLX] glXGetFBConfigs() failed");
        return nullptr;
    }
    NS_ASSERTION(numConfigs > 0, "No FBConfigs found!");

    // XXX the visual ID is almost certainly the LOCAL_GLX_FBCONFIG_ID, so
    // we could probably do this first and replace the glXGetFBConfigs
    // with glXChooseConfigs.  Docs are sparklingly clear as always.
    XWindowAttributes widgetAttrs;
    if (!XGetWindowAttributes(display, window, &widgetAttrs)) {
        NS_WARNING("[GLX] XGetWindowAttributes() failed");
        return nullptr;
    }
    const VisualID widgetVisualID = XVisualIDFromVisual(widgetAttrs.visual);
#ifdef DEBUG
    printf("[GLX] widget has VisualID 0x%lx\n", widgetVisualID);
#endif

    int matchIndex = -1;

    for (int i = 0; i < numConfigs; i++) {
        int visid = None;
        sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i], LOCAL_GLX_VISUAL_ID, &visid);
        if (!visid) {
            continue;
        }
        if (sGLXLibrary.IsATI()) {
            int depth;
            Visual *visual;
            FindVisualAndDepth(display, visid, &visual, &depth);
            if (depth == widgetAttrs.depth &&
                AreCompatibleVisuals(widgetAttrs.visual, visual)) {
                matchIndex = i;
                break;
            }
        } else {
            if (widgetVisualID == static_cast<VisualID>(visid)) {
                matchIndex = i;
                break;
            }
        }
    }

    if (matchIndex == -1) {
        NS_WARNING("[GLX] Couldn't find a FBConfig matching widget visual");
        return nullptr;
    }

    GLContextGLX *shareContext = GetGlobalContextGLX();

    SurfaceCaps caps = SurfaceCaps::Any();
    nsRefPtr<GLContextGLX> glContext = GLContextGLX::CreateGLContext(caps,
                                                                     shareContext,
                                                                     false,
                                                                     display,
                                                                     window,
                                                                     cfgs[matchIndex],
                                                                     false);

    return glContext.forget();
}

static already_AddRefed<GLContextGLX>
CreateOffscreenPixmapContext(const gfxIntSize& size)
{
    GLXLibrary& glx = sGLXLibrary;
    if (!glx.EnsureInitialized()) {
        return nullptr;
    }

    Display *display = DefaultXDisplay();
    int xscreen = DefaultScreen(display);

    int attribs[] = {
        LOCAL_GLX_DRAWABLE_TYPE, LOCAL_GLX_PIXMAP_BIT,
        LOCAL_GLX_X_RENDERABLE, True,
        0
    };
    int numConfigs = 0;

    ScopedXFree<GLXFBConfig> cfgs;
    cfgs = glx.xChooseFBConfig(display,
                               xscreen,
                               attribs,
                               &numConfigs);
    if (!cfgs) {
        return nullptr;
    }

    MOZ_ASSERT(numConfigs > 0,
               "glXChooseFBConfig() failed to match our requested format and violated its spec!");

    int visid = None;
    int chosenIndex = 0;

    for (int i = 0; i < numConfigs; ++i) {
        int dtype;

        if (glx.xGetFBConfigAttrib(display, cfgs[i], LOCAL_GLX_DRAWABLE_TYPE, &dtype) != Success
            || !(dtype & LOCAL_GLX_PIXMAP_BIT))
        {
            continue;
        }
        if (glx.xGetFBConfigAttrib(display, cfgs[i], LOCAL_GLX_VISUAL_ID, &visid) != Success
            || visid == 0)
        {
            continue;
        }

        chosenIndex = i;
        break;
    }

    if (!visid) {
        NS_WARNING("glXChooseFBConfig() didn't give us any configs with visuals!");
        return nullptr;
    }

    Visual *visual;
    int depth;
    FindVisualAndDepth(display, visid, &visual, &depth);
    ScopedXErrorHandler xErrorHandler;
    GLXPixmap glxpixmap = 0;
    bool error = false;

    gfxIntSize dummySize(16, 16);
    nsRefPtr<gfxXlibSurface> xsurface = gfxXlibSurface::Create(DefaultScreenOfDisplay(display),
                                                               visual,
                                                               dummySize);
    if (xsurface->CairoStatus() != 0) {
        error = true;
        goto DONE_CREATING_PIXMAP;
    }

    // Handle slightly different signature between glXCreatePixmap and
    // its pre-GLX-1.3 extension equivalent (though given the ABI, we
    // might not need to).
    if (glx.GLXVersionCheck(1, 3)) {
        glxpixmap = glx.xCreatePixmap(display,
                                          cfgs[chosenIndex],
                                          xsurface->XDrawable(),
                                          nullptr);
    } else {
        glxpixmap = glx.xCreateGLXPixmapWithConfig(display,
                                                       cfgs[chosenIndex],
                                                       xsurface->
                                                       XDrawable());
    }
    if (glxpixmap == 0) {
        error = true;
    }

DONE_CREATING_PIXMAP:

    nsRefPtr<GLContextGLX> glContext;
    bool serverError = xErrorHandler.SyncAndGetError(display);

    if (!error && // earlier recorded error
        !serverError)
    {
        // We might have an alpha channel, but it doesn't matter.
        SurfaceCaps dummyCaps = SurfaceCaps::Any();
        GLContextGLX* shareContext = GetGlobalContextGLX();

        glContext = GLContextGLX::CreateGLContext(dummyCaps,
                                                  shareContext,
                                                  true,
                                                  display,
                                                  glxpixmap,
                                                  cfgs[chosenIndex],
                                                  true,
                                                  xsurface);
    }

    return glContext.forget();
}

already_AddRefed<GLContext>
GLContextProviderGLX::CreateOffscreen(const gfxIntSize& size,
                                      const SurfaceCaps& caps)
{
    gfxIntSize dummySize = gfxIntSize(16, 16);
    nsRefPtr<GLContextGLX> glContext =
        CreateOffscreenPixmapContext(dummySize);

    if (!glContext)
        return nullptr;

    if (!glContext->InitOffscreen(ToIntSize(size), caps))
        return nullptr;

    return glContext.forget();
}

static StaticRefPtr<GLContext> gGlobalContext;

GLContext*
GLContextProviderGLX::GetGlobalContext()
{
    static bool checkedContextSharing = false;
    static bool useContextSharing = false;

    if (!checkedContextSharing) {
        useContextSharing = getenv("MOZ_DISABLE_CONTEXT_SHARING_GLX") == 0;
        checkedContextSharing = true;
    }

    // TODO: get GLX context sharing to work well with multiple threads
    if (!useContextSharing) {
        return nullptr;
    }

    static bool triedToCreateContext = false;
    if (!triedToCreateContext && !gGlobalContext) {
        triedToCreateContext = true;

        gfxIntSize dummySize = gfxIntSize(16, 16);
        // StaticPtr doesn't support assignments from already_AddRefed,
        // so use a temporary nsRefPtr to make the reference counting
        // fall out correctly.
        nsRefPtr<GLContext> holder = CreateOffscreenPixmapContext(dummySize);
        gGlobalContext = holder;
    }

    return gGlobalContext;
}

void
GLContextProviderGLX::Shutdown()
{
    gGlobalContext = nullptr;
}

} /* namespace gl */
} /* namespace mozilla */