/* -*- 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/. */

#include "GLContext.h"
#include "mozilla/Util.h"

#if defined(XP_UNIX)

#ifdef MOZ_WIDGET_GTK
#include <gdk/gdkx.h>
// we're using default display for now
#define GET_NATIVE_WINDOW(aWidget) (EGLNativeWindowType)GDK_WINDOW_XID((GdkWindow *) aWidget->GetNativeData(NS_NATIVE_WINDOW))
#elif defined(MOZ_WIDGET_GONK)
#define GET_NATIVE_WINDOW(aWidget) ((EGLNativeWindowType)aWidget->GetNativeData(NS_NATIVE_WINDOW))
#include "HwcComposer2D.h"
#include "libdisplay/GonkDisplay.h"
#endif

#if defined(ANDROID)
/* from widget */
#if defined(MOZ_WIDGET_ANDROID)
#include "AndroidBridge.h"
#include "nsSurfaceTexture.h"
#endif

#include <android/log.h>
#define LOG(args...)  __android_log_print(ANDROID_LOG_INFO, "Gonk" , ## args)

# if defined(MOZ_WIDGET_GONK)
#  include "cutils/properties.h"
#  include <ui/GraphicBuffer.h>

using namespace android;
# endif

#endif

#define GLES2_LIB "libGLESv2.so"
#define GLES2_LIB2 "libGLESv2.so.2"

#elif defined(XP_WIN)

#include "nsIFile.h"

#define GLES2_LIB "libGLESv2.dll"

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN 1
#endif

#include <windows.h>

// a little helper
class AutoDestroyHWND {
public:
    AutoDestroyHWND(HWND aWnd = nullptr)
        : mWnd(aWnd)
    {
    }

    ~AutoDestroyHWND() {
        if (mWnd) {
            ::DestroyWindow(mWnd);
        }
    }

    operator HWND() {
        return mWnd;
    }

    HWND forget() {
        HWND w = mWnd;
        mWnd = nullptr;
        return w;
    }

    HWND operator=(HWND aWnd) {
        if (mWnd && mWnd != aWnd) {
            ::DestroyWindow(mWnd);
        }
        mWnd = aWnd;
        return mWnd;
    }

    HWND mWnd;
};

#else

#error "Platform not recognized"

#endif

#include "mozilla/Preferences.h"
#include "gfxUtils.h"
#include "gfxFailure.h"
#include "gfxASurface.h"
#include "gfxImageSurface.h"
#include "gfxPlatform.h"
#include "GLContextProvider.h"
#include "GLLibraryEGL.h"
#include "TextureImageEGL.h"
#include "nsDebug.h"
#include "nsThreadUtils.h"

#include "nsIWidget.h"

#include "gfxCrashReporterUtils.h"

#include "ScopedGLHelpers.h"
#include "GLBlitHelper.h"

using namespace mozilla::gfx;

#ifdef MOZ_WIDGET_GONK
extern nsIntRect gScreenBounds;
#endif

namespace mozilla {
namespace gl {

#define ADD_ATTR_2(_array, _k, _v) do {         \
    (_array).AppendElement(_k);                 \
    (_array).AppendElement(_v);                 \
} while (0)

#define ADD_ATTR_1(_array, _k) do {             \
    (_array).AppendElement(_k);                 \
} while (0)

static bool
CreateConfig(EGLConfig* aConfig);

static EGLint gContextAttribs[] = {
    LOCAL_EGL_CONTEXT_CLIENT_VERSION, 2,
    LOCAL_EGL_NONE
};

static EGLint gContextAttribsRobustness[] = {
    LOCAL_EGL_CONTEXT_CLIENT_VERSION, 2,
    //LOCAL_EGL_CONTEXT_ROBUST_ACCESS_EXT, LOCAL_EGL_TRUE,
    LOCAL_EGL_CONTEXT_RESET_NOTIFICATION_STRATEGY_EXT, LOCAL_EGL_LOSE_CONTEXT_ON_RESET_EXT,
    LOCAL_EGL_NONE
};

static int
next_power_of_two(int v)
{
    v--;
    v |= v >> 1;
    v |= v >> 2;
    v |= v >> 4;
    v |= v >> 8;
    v |= v >> 16;
    v++;

    return v;
}

static bool
is_power_of_two(int v)
{
    NS_ASSERTION(v >= 0, "bad value");

    if (v == 0)
        return true;

    return (v & (v-1)) == 0;
}

static void
DestroySurface(EGLSurface oldSurface) {
    if (oldSurface != EGL_NO_SURFACE) {
        sEGLLibrary.fMakeCurrent(EGL_DISPLAY(),
                                 EGL_NO_SURFACE, EGL_NO_SURFACE,
                                 EGL_NO_CONTEXT);
        sEGLLibrary.fDestroySurface(EGL_DISPLAY(), oldSurface);
    }
}

static EGLSurface
CreateSurfaceForWindow(nsIWidget* widget, const EGLConfig& config) {
    EGLSurface newSurface = EGL_NO_SURFACE;

    #ifdef MOZ_ANDROID_OMTC
        mozilla::AndroidBridge::Bridge()->RegisterCompositor();
        newSurface = mozilla::AndroidBridge::Bridge()->CreateEGLSurfaceForCompositor();
        if (newSurface == EGL_NO_SURFACE) {
            return EGL_NO_SURFACE;
        }
    #else
        MOZ_ASSERT(widget != nullptr);
        newSurface = sEGLLibrary.fCreateWindowSurface(EGL_DISPLAY(), config, GET_NATIVE_WINDOW(widget), 0);
        #ifdef MOZ_WIDGET_GONK
            gScreenBounds.x = 0;
            gScreenBounds.y = 0;
            sEGLLibrary.fQuerySurface(EGL_DISPLAY(), newSurface, LOCAL_EGL_WIDTH, &gScreenBounds.width);
            sEGLLibrary.fQuerySurface(EGL_DISPLAY(), newSurface, LOCAL_EGL_HEIGHT, &gScreenBounds.height);
        #endif
    #endif
    return newSurface;
}

class GLContextEGL : public GLContext
{
    friend class TextureImageEGL;

    static already_AddRefed<GLContextEGL>
    CreateGLContext(const SurfaceCaps& caps,
                    GLContextEGL *shareContext,
                    bool isOffscreen,
                    EGLConfig config,
                    EGLSurface surface)
    {
        if (sEGLLibrary.fBindAPI(LOCAL_EGL_OPENGL_ES_API) == LOCAL_EGL_FALSE) {
            NS_WARNING("Failed to bind API to GLES!");
            return nullptr;
        }

        EGLContext eglShareContext = shareContext ? shareContext->mContext
                                                  : EGL_NO_CONTEXT;
        EGLint* attribs = sEGLLibrary.HasRobustness() ? gContextAttribsRobustness
                                                      : gContextAttribs;

        EGLContext context = sEGLLibrary.fCreateContext(EGL_DISPLAY(),
                                                        config,
                                                        eglShareContext,
                                                        attribs);
        if (!context && shareContext) {
            shareContext = nullptr;
            context = sEGLLibrary.fCreateContext(EGL_DISPLAY(),
                                                 config,
                                                 EGL_NO_CONTEXT,
                                                 attribs);
        }
        if (!context) {
            NS_WARNING("Failed to create EGLContext!");
            return nullptr;
        }

        nsRefPtr<GLContextEGL> glContext = new GLContextEGL(caps,
                                                            shareContext,
                                                            isOffscreen,
                                                            config,
                                                            surface,
                                                            context);

        if (!glContext->Init())
            return nullptr;

        return glContext.forget();
    }

public:
    GLContextEGL(const SurfaceCaps& caps,
                 GLContext* shareContext,
                 bool isOffscreen,
                 EGLConfig config,
                 EGLSurface surface,
                 EGLContext context)
        : GLContext(caps, shareContext, isOffscreen)
        , mConfig(config)
        , mSurface(surface)
        , mSurfaceOverride(EGL_NO_SURFACE)
        , mContext(context)
        , mThebesSurface(nullptr)
        , mBound(false)
        , mIsPBuffer(false)
        , mIsDoubleBuffered(false)
        , mCanBindToTexture(false)
        , mShareWithEGLImage(false)
    {
        // any EGL contexts will always be GLESv2
        SetProfileVersion(ContextProfile::OpenGLES, 200);

#ifdef DEBUG
        printf_stderr("Initializing context %p surface %p on display %p\n", mContext, mSurface, EGL_DISPLAY());
#endif
#if defined(MOZ_WIDGET_GONK)
        if (!mIsOffscreen) {
            mHwc = HwcComposer2D::GetInstance();
            MOZ_ASSERT(!mHwc->Initialized());

            if (mHwc->Init(EGL_DISPLAY(), mSurface)) {
                NS_WARNING("HWComposer initialization failed!");
                mHwc = nullptr;
            }
        }
#endif
    }

    ~GLContextEGL()
    {
        MarkDestroyed();

#ifdef DEBUG
        printf_stderr("Destroying context %p surface %p on display %p\n", mContext, mSurface, EGL_DISPLAY());
#endif

        sEGLLibrary.fDestroyContext(EGL_DISPLAY(), mContext);
        mozilla::gl::DestroySurface(mSurface);
    }

    GLContextType GetContextType() {
        return ContextTypeEGL;
    }

    bool Init()
    {
#if defined(ANDROID)
        // We can't use LoadApitraceLibrary here because the GLContext
        // expects its own handle to the GL library
        if (!OpenLibrary(APITRACE_LIB))
#endif
            if (!OpenLibrary(GLES2_LIB)) {
#if defined(XP_UNIX)
                if (!OpenLibrary(GLES2_LIB2)) {
                    NS_WARNING("Couldn't load GLES2 LIB.");
                    return false;
                }
#endif
            }

        SetupLookupFunction();
        if (!InitWithPrefix("gl", true))
            return false;

        bool current = MakeCurrent();
        if (!current) {
            gfx::LogFailure(NS_LITERAL_CSTRING(
                "Couldn't get device attachments for device."));
            return false;
        }

        PR_STATIC_ASSERT(sizeof(GLint) >= sizeof(int32_t));
        mMaxTextureImageSize = INT32_MAX;

        mShareWithEGLImage = sEGLLibrary.HasKHRImageBase() &&
                             sEGLLibrary.HasKHRImageTexture2D() &&
                             IsExtensionSupported(OES_EGL_image);

        return true;
    }

    bool IsDoubleBuffered() {
        return mIsDoubleBuffered;
    }

    void SetIsDoubleBuffered(bool aIsDB) {
        mIsDoubleBuffered = aIsDB;
    }

    virtual EGLContext GetEGLContext() {
        return mContext;
    }

    virtual GLLibraryEGL* GetLibraryEGL() {
        return &sEGLLibrary;
    }


    bool SupportsRobustness()
    {
        return sEGLLibrary.HasRobustness();
    }

    virtual bool IsANGLE()
    {
        return sEGLLibrary.IsANGLE();
    }

    bool BindTexImage()
    {
        if (!mSurface)
            return false;

        if (mBound && !ReleaseTexImage())
            return false;

        EGLBoolean success = sEGLLibrary.fBindTexImage(EGL_DISPLAY(),
            (EGLSurface)mSurface, LOCAL_EGL_BACK_BUFFER);
        if (success == LOCAL_EGL_FALSE)
            return false;

        mBound = true;
        return true;
    }

    bool ReleaseTexImage()
    {
        if (!mBound)
            return true;

        if (!mSurface)
            return false;

        EGLBoolean success;
        success = sEGLLibrary.fReleaseTexImage(EGL_DISPLAY(),
                                               (EGLSurface)mSurface,
                                               LOCAL_EGL_BACK_BUFFER);
        if (success == LOCAL_EGL_FALSE)
            return false;

        mBound = false;
        return true;
    }

#ifdef MOZ_WIDGET_GONK
    EGLImage CreateEGLImageForNativeBuffer(void* buffer) MOZ_OVERRIDE
    {
        EGLint attrs[] = {
            LOCAL_EGL_IMAGE_PRESERVED, LOCAL_EGL_TRUE,
            LOCAL_EGL_NONE, LOCAL_EGL_NONE
        };
        return sEGLLibrary.fCreateImage(EGL_DISPLAY(),
                                        EGL_NO_CONTEXT,
                                        LOCAL_EGL_NATIVE_BUFFER_ANDROID,
                                        buffer, attrs);
    }

    void DestroyEGLImage(EGLImage image) MOZ_OVERRIDE
    {
        sEGLLibrary.fDestroyImage(EGL_DISPLAY(), image);
    }
#endif

    virtual void SetEGLSurfaceOverride(EGLSurface surf) MOZ_OVERRIDE {
        if (Screen()) {
            /* Blit `draw` to `read` if we need to, before we potentially juggle
             * `read` around. If we don't, we might attach a different `read`,
             * and *then* hit AssureBlitted, which will blit a dirty `draw` onto
             * the wrong `read`!
             */
            Screen()->AssureBlitted();
        }

        mSurfaceOverride = surf ? (EGLSurface) surf : mSurface;
        MakeCurrent(true);
    }

    bool MakeCurrentImpl(bool aForce = false) {
        bool succeeded = true;

        // Assume that EGL has the same problem as WGL does,
        // where MakeCurrent with an already-current context is
        // still expensive.
        if (aForce || sEGLLibrary.fGetCurrentContext() != mContext) {
            EGLSurface surface = mSurfaceOverride != EGL_NO_SURFACE
                                 ? mSurfaceOverride
                                 : mSurface;
            succeeded = sEGLLibrary.fMakeCurrent(EGL_DISPLAY(),
                                                 surface, surface,
                                                 mContext);
            int eglError = sEGLLibrary.fGetError();
            if (!succeeded) {
                if (eglError == LOCAL_EGL_CONTEXT_LOST) {
                    mContextLost = true;
                    NS_WARNING("EGL context has been lost.");
                } else {
                    NS_WARNING("Failed to make GL context current!");
#ifdef DEBUG
                    printf_stderr("EGL Error: 0x%04x\n", eglError);
#endif
                }
            }
        }

        return succeeded;
    }

    virtual bool IsCurrent() {
        return sEGLLibrary.fGetCurrentContext() == mContext;
    }

    virtual bool
    RenewSurface() {
#ifndef MOZ_WIDGET_ANDROID
        MOZ_CRASH("unimplemented");
        // to support this on non-Android platforms, need to keep track of the nsIWidget that
        // this GLContext was created for (with CreateForWindow) so that we know what to
        // pass again to CreateSurfaceForWindow below.
        // The reason why Android doesn't need this is that it delegates EGLSurface creation to
        // Java code which is the only thing that knows about our actual widget.
#endif
        // unconditionally release the surface and create a new one. Don't try to optimize this away.
        // If we get here, then by definition we know that we want to get a new surface.
        ReleaseSurface();
        mSurface = mozilla::gl::CreateSurfaceForWindow(nullptr, mConfig); // the nullptr here is where we assume Android.
        if (mSurface == EGL_NO_SURFACE) {
            return false;
        }
        return MakeCurrent(true);
    }

    virtual void
    ReleaseSurface() {
        DestroySurface(mSurface);
        mSurface = nullptr;
    }

    bool SetupLookupFunction()
    {
        mLookupFunc = (PlatformLookupFunction)sEGLLibrary.mSymbols.fGetProcAddress;
        return true;
    }

    void *GetNativeData(NativeDataType aType)
    {
        switch (aType) {
        case NativeGLContext:
            return mContext;

        default:
            return nullptr;
        }
    }

    bool SwapBuffers()
    {
        if (mSurface) {
#ifdef MOZ_WIDGET_GONK
            if (!mIsOffscreen) {
                if (mHwc) {
                    return mHwc->Render(EGL_DISPLAY(), mSurface);
                } else {
                    return GetGonkDisplay()->SwapBuffers(EGL_DISPLAY(), mSurface);
                }
            } else
#endif
                return sEGLLibrary.fSwapBuffers(EGL_DISPLAY(), mSurface);
        } else {
            return false;
        }
    }
    // GLContext interface - returns Tiled Texture Image in our case
    virtual already_AddRefed<TextureImage>
    CreateTextureImage(const nsIntSize& aSize,
                       TextureImage::ContentType aContentType,
                       GLenum aWrapMode,
                       TextureImage::Flags aFlags = TextureImage::NoFlags,
                       TextureImage::ImageFormat aImageFormat = gfxImageFormatUnknown);

    // a function to generate Tiles for Tiled Texture Image
    virtual already_AddRefed<TextureImage>
    TileGenFunc(const nsIntSize& aSize,
                TextureImage::ContentType aContentType,
                TextureImage::Flags aFlags = TextureImage::NoFlags,
                TextureImage::ImageFormat aImageFormat = gfxImageFormatUnknown) MOZ_OVERRIDE;
    // hold a reference to the given surface
    // for the lifetime of this context.
    void HoldSurface(gfxASurface *aSurf) {
        mThebesSurface = aSurf;
    }

    EGLContext Context() {
        return mContext;
    }

    bool BindTex2DOffscreen(GLContext *aOffscreen);
    void UnbindTex2DOffscreen(GLContext *aOffscreen);
    bool ResizeOffscreen(const gfxIntSize& aNewSize);
    void BindOffscreenFramebuffer();

    static already_AddRefed<GLContextEGL>
    CreateEGLPixmapOffscreenContext(const gfxIntSize& size);

    static already_AddRefed<GLContextEGL>
    CreateEGLPBufferOffscreenContext(const gfxIntSize& size);

protected:
    friend class GLContextProviderEGL;

    EGLConfig  mConfig;
    EGLSurface mSurface;
    EGLSurface mSurfaceOverride;
    EGLContext mContext;
    nsRefPtr<gfxASurface> mThebesSurface;
    bool mBound;

    bool mIsPBuffer;
    bool mIsDoubleBuffered;
    bool mCanBindToTexture;
    bool mShareWithEGLImage;
#ifdef MOZ_WIDGET_GONK
    nsRefPtr<HwcComposer2D> mHwc;
#endif

    static EGLSurface CreatePBufferSurfaceTryingPowerOfTwo(EGLConfig config,
                                                           EGLenum bindToTextureFormat,
                                                           gfxIntSize& pbsize)
    {
        nsTArray<EGLint> pbattrs(16);
        EGLSurface surface = nullptr;

    TRY_AGAIN_POWER_OF_TWO:
        pbattrs.Clear();
        pbattrs.AppendElement(LOCAL_EGL_WIDTH); pbattrs.AppendElement(pbsize.width);
        pbattrs.AppendElement(LOCAL_EGL_HEIGHT); pbattrs.AppendElement(pbsize.height);

        if (bindToTextureFormat != LOCAL_EGL_NONE) {
            pbattrs.AppendElement(LOCAL_EGL_TEXTURE_TARGET);
            pbattrs.AppendElement(LOCAL_EGL_TEXTURE_2D);

            pbattrs.AppendElement(LOCAL_EGL_TEXTURE_FORMAT);
            pbattrs.AppendElement(bindToTextureFormat);
        }

        pbattrs.AppendElement(LOCAL_EGL_NONE);

        surface = sEGLLibrary.fCreatePbufferSurface(EGL_DISPLAY(), config, &pbattrs[0]);
        if (!surface) {
            if (!is_power_of_two(pbsize.width) ||
                !is_power_of_two(pbsize.height))
            {
                if (!is_power_of_two(pbsize.width))
                    pbsize.width = next_power_of_two(pbsize.width);
                if (!is_power_of_two(pbsize.height))
                    pbsize.height = next_power_of_two(pbsize.height);

                NS_WARNING("Failed to create pbuffer, trying power of two dims");
                goto TRY_AGAIN_POWER_OF_TWO;
            }

            NS_WARNING("Failed to create pbuffer surface");
            return nullptr;
        }

        return surface;
    }
};

bool
GLContextEGL::ResizeOffscreen(const gfxIntSize& aNewSize)
{
	return ResizeScreenBuffer(aNewSize);
}

already_AddRefed<TextureImage>
GLContextEGL::CreateTextureImage(const nsIntSize& aSize,
                                 TextureImage::ContentType aContentType,
                                 GLenum aWrapMode,
                                 TextureImage::Flags aFlags,
                                 TextureImage::ImageFormat aImageFormat)
{
    nsRefPtr<TextureImage> t = new gl::TiledTextureImage(this, aSize, aContentType, aFlags, aImageFormat);
    return t.forget();
}

already_AddRefed<TextureImage>
GLContextEGL::TileGenFunc(const nsIntSize& aSize,
                          TextureImage::ContentType aContentType,
                          TextureImage::Flags aFlags,
                          TextureImage::ImageFormat aImageFormat)
{
  MakeCurrent();

  GLuint texture;
  fGenTextures(1, &texture);

  nsRefPtr<TextureImageEGL> teximage =
      new TextureImageEGL(texture, aSize, LOCAL_GL_CLAMP_TO_EDGE, aContentType,
                          this, aFlags, TextureImage::Created, aImageFormat);
  
  teximage->BindTexture(LOCAL_GL_TEXTURE0);

  GLint texfilter = aFlags & TextureImage::UseNearestFilter ? LOCAL_GL_NEAREST : LOCAL_GL_LINEAR;
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MIN_FILTER, texfilter);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MAG_FILTER, texfilter);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_S, LOCAL_GL_CLAMP_TO_EDGE);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_T, LOCAL_GL_CLAMP_TO_EDGE);

  return teximage.forget();
}

static const EGLint kEGLConfigAttribsOffscreenPBuffer[] = {
    LOCAL_EGL_SURFACE_TYPE,    LOCAL_EGL_PBUFFER_BIT,
    LOCAL_EGL_RENDERABLE_TYPE, LOCAL_EGL_OPENGL_ES2_BIT,
    LOCAL_EGL_NONE
};

static const EGLint kEGLConfigAttribsRGB16[] = {
    LOCAL_EGL_SURFACE_TYPE,    LOCAL_EGL_WINDOW_BIT,
    LOCAL_EGL_RENDERABLE_TYPE, LOCAL_EGL_OPENGL_ES2_BIT,
    LOCAL_EGL_RED_SIZE,        5,
    LOCAL_EGL_GREEN_SIZE,      6,
    LOCAL_EGL_BLUE_SIZE,       5,
    LOCAL_EGL_ALPHA_SIZE,      0,
    LOCAL_EGL_NONE
};

static const EGLint kEGLConfigAttribsRGB24[] = {
    LOCAL_EGL_SURFACE_TYPE,    LOCAL_EGL_WINDOW_BIT,
    LOCAL_EGL_RENDERABLE_TYPE, LOCAL_EGL_OPENGL_ES2_BIT,
    LOCAL_EGL_RED_SIZE,        8,
    LOCAL_EGL_GREEN_SIZE,      8,
    LOCAL_EGL_BLUE_SIZE,       8,
    LOCAL_EGL_ALPHA_SIZE,      0,
    LOCAL_EGL_NONE
};

static const EGLint kEGLConfigAttribsRGBA32[] = {
    LOCAL_EGL_SURFACE_TYPE,    LOCAL_EGL_WINDOW_BIT,
    LOCAL_EGL_RENDERABLE_TYPE, LOCAL_EGL_OPENGL_ES2_BIT,
    LOCAL_EGL_RED_SIZE,        8,
    LOCAL_EGL_GREEN_SIZE,      8,
    LOCAL_EGL_BLUE_SIZE,       8,
    LOCAL_EGL_ALPHA_SIZE,      8,
#if defined(MOZ_WIDGET_GONK) && ANDROID_VERSION >= 17
    LOCAL_EGL_FRAMEBUFFER_TARGET_ANDROID, LOCAL_EGL_TRUE,
#endif
    LOCAL_EGL_NONE
};

static bool
CreateConfig(EGLConfig* aConfig, int32_t depth)
{
    EGLConfig configs[64];
    const EGLint* attribs;
    EGLint ncfg = ArrayLength(configs);

    switch (depth) {
        case 16:
            attribs = kEGLConfigAttribsRGB16;
            break;
        case 24:
            attribs = kEGLConfigAttribsRGB24;
            break;
        case 32:
            attribs = kEGLConfigAttribsRGBA32;
            break;
        default:
            NS_ERROR("Unknown pixel depth");
            return false;
    }

    if (!sEGLLibrary.fChooseConfig(EGL_DISPLAY(), attribs,
                                   configs, ncfg, &ncfg) ||
        ncfg < 1) {
        return false;
    }

    for (int j = 0; j < ncfg; ++j) {
        EGLConfig config = configs[j];
        EGLint r, g, b, a;

        if (sEGLLibrary.fGetConfigAttrib(EGL_DISPLAY(), config,
                                         LOCAL_EGL_RED_SIZE, &r) &&
            sEGLLibrary.fGetConfigAttrib(EGL_DISPLAY(), config,
                                         LOCAL_EGL_GREEN_SIZE, &g) &&
            sEGLLibrary.fGetConfigAttrib(EGL_DISPLAY(), config,
                                         LOCAL_EGL_BLUE_SIZE, &b) &&
            sEGLLibrary.fGetConfigAttrib(EGL_DISPLAY(), config,
                                         LOCAL_EGL_ALPHA_SIZE, &a) &&
            ((depth == 16 && r == 5 && g == 6 && b == 5) ||
             (depth == 24 && r == 8 && g == 8 && b == 8) ||
             (depth == 32 && r == 8 && g == 8 && b == 8 && a == 8)))
        {
            *aConfig = config;
            return true;
        }
    }
    return false;
}

// Return true if a suitable EGLConfig was found and pass it out
// through aConfig.  Return false otherwise.
//
// NB: It's entirely legal for the returned EGLConfig to be valid yet
// have the value null.
static bool
CreateConfig(EGLConfig* aConfig)
{
    int32_t depth = gfxPlatform::GetPlatform()->GetScreenDepth();
    if (!CreateConfig(aConfig, depth)) {
#ifdef MOZ_WIDGET_ANDROID
        // Bug 736005
        // Android doesn't always support 16 bit so also try 24 bit
        if (depth == 16) {
            return CreateConfig(aConfig, 24);
        }
#endif
        return false;
    } else {
        return true;
    }
}

already_AddRefed<GLContext>
GLContextProviderEGL::CreateForWindow(nsIWidget *aWidget)
{
    if (!sEGLLibrary.EnsureInitialized()) {
        MOZ_CRASH("Failed to load EGL library!\n");
        return nullptr;
    }

    bool doubleBuffered = true;

    EGLConfig config;
    if (!CreateConfig(&config)) {
        MOZ_CRASH("Failed to create EGLConfig!\n");
        return nullptr;
    }

    EGLSurface surface = mozilla::gl::CreateSurfaceForWindow(aWidget, config);

    if (surface == EGL_NO_SURFACE) {
        MOZ_CRASH("Failed to create EGLSurface!\n");
        return nullptr;
    }

    SurfaceCaps caps = SurfaceCaps::Any();
    nsRefPtr<GLContextEGL> glContext =
        GLContextEGL::CreateGLContext(caps,
                                      nullptr, false,
                                      config, surface);

    if (!glContext) {
        MOZ_CRASH("Failed to create EGLContext!\n");
        DestroySurface(surface);
        return nullptr;
    }

    glContext->MakeCurrent();
    glContext->SetIsDoubleBuffered(doubleBuffered);

    return glContext.forget();
}

already_AddRefed<GLContextEGL>
GLContextEGL::CreateEGLPBufferOffscreenContext(const gfxIntSize& size)
{
    EGLConfig config;
    EGLSurface surface;

    const EGLint numConfigs = 1; // We only need one.
    EGLConfig configs[numConfigs];
    EGLint foundConfigs = 0;
    if (!sEGLLibrary.fChooseConfig(EGL_DISPLAY(),
                                   kEGLConfigAttribsOffscreenPBuffer,
                                   configs, numConfigs,
                                   &foundConfigs)
        || foundConfigs == 0)
    {
        NS_WARNING("No EGL Config for minimal PBuffer!");
        return nullptr;
    }

    // We absolutely don't care, so just pick the first one.
    config = configs[0];
    if (GLContext::DebugMode())
        sEGLLibrary.DumpEGLConfig(config);

    gfxIntSize pbSize(size);
    surface = GLContextEGL::CreatePBufferSurfaceTryingPowerOfTwo(config,
                                                                 LOCAL_EGL_NONE,
                                                                 pbSize);
    if (!surface) {
        NS_WARNING("Failed to create PBuffer for context!");
        return nullptr;
    }

    SurfaceCaps dummyCaps = SurfaceCaps::Any();
    nsRefPtr<GLContextEGL> glContext =
        GLContextEGL::CreateGLContext(dummyCaps,
                                      nullptr, true,
                                      config, surface);
    if (!glContext) {
        NS_WARNING("Failed to create GLContext from PBuffer");
        sEGLLibrary.fDestroySurface(EGL_DISPLAY(), surface);
        return nullptr;
    }

    if (!glContext->Init()) {
        NS_WARNING("Failed to initialize GLContext!");
        // GLContextEGL::dtor will destroy |surface| for us.
        return nullptr;
    }

    return glContext.forget();
}

already_AddRefed<GLContextEGL>
GLContextEGL::CreateEGLPixmapOffscreenContext(const gfxIntSize& size)
{
    gfxASurface *thebesSurface = nullptr;
    EGLNativePixmapType pixmap = 0;

    if (!pixmap) {
        return nullptr;
    }

    EGLSurface surface = 0;
    EGLConfig config = 0;

    if (!config) {
        return nullptr;
    }
    MOZ_ASSERT(surface);

    SurfaceCaps dummyCaps = SurfaceCaps::Any();
    nsRefPtr<GLContextEGL> glContext =
        GLContextEGL::CreateGLContext(dummyCaps,
                                      nullptr, true,
                                      config, surface);
    if (!glContext) {
        NS_WARNING("Failed to create GLContext from XSurface");
        sEGLLibrary.fDestroySurface(EGL_DISPLAY(), surface);
        return nullptr;
    }

    if (!glContext->Init()) {
        NS_WARNING("Failed to initialize GLContext!");
        // GLContextEGL::dtor will destroy |surface| for us.
        return nullptr;
    }

    glContext->HoldSurface(thebesSurface);

    return glContext.forget();
}

// Under EGL, on Android, pbuffers are supported fine, though
// often without the ability to texture from them directly.
already_AddRefed<GLContext>
GLContextProviderEGL::CreateOffscreen(const gfxIntSize& size,
                                      const SurfaceCaps& caps,
                                      ContextFlags flags)
{
    if (!sEGLLibrary.EnsureInitialized()) {
        return nullptr;
    }

    gfxIntSize dummySize = gfxIntSize(16, 16);
    nsRefPtr<GLContextEGL> glContext;
    glContext = GLContextEGL::CreateEGLPBufferOffscreenContext(dummySize);

    if (!glContext)
        return nullptr;

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

    return glContext.forget();
}

// Don't want a global context on Android as 1) share groups across 2 threads fail on many Tegra drivers (bug 759225)
// and 2) some mobile devices have a very strict limit on global number of GL contexts (bug 754257)
// and 3) each EGL context eats 750k on B2G (bug 813783)
GLContext *
GLContextProviderEGL::GetGlobalContext(const ContextFlags)
{
    return nullptr;
}

void
GLContextProviderEGL::Shutdown()
{
}

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