// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gl/gl_surface_egl.h"

#include <stddef.h>
#include <stdint.h>

#include <map>
#include <memory>
#include <vector>

#include "base/command_line.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/message_loop/message_loop.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_number_conversions.h"
#include "base/sys_info.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gl/angle_platform_impl.h"
#include "ui/gl/egl_util.h"
#include "ui/gl/gl_context.h"
#include "ui/gl/gl_context_egl.h"
#include "ui/gl/gl_image.h"
#include "ui/gl/gl_implementation.h"
#include "ui/gl/gl_surface_stub.h"
#include "ui/gl/gl_switches.h"
#include "ui/gl/scoped_make_current.h"
#include "ui/gl/sync_control_vsync_provider.h"

#if defined(USE_X11) && !defined(OS_CHROMEOS)
extern "C" {
#include <X11/Xlib.h>
#define Status int
}
#include "ui/base/x/x11_util_internal.h"  // nogncheck
#endif

#if defined(OS_ANDROID)
#include <android/native_window_jni.h>
#endif

#if !defined(EGL_FIXED_SIZE_ANGLE)
#define EGL_FIXED_SIZE_ANGLE 0x3201
#endif

#if !defined(EGL_OPENGL_ES3_BIT)
#define EGL_OPENGL_ES3_BIT 0x00000040
#endif

// From ANGLE's egl/eglext.h.

#ifndef EGL_ANGLE_platform_angle
#define EGL_ANGLE_platform_angle 1
#define EGL_PLATFORM_ANGLE_ANGLE 0x3202
#define EGL_PLATFORM_ANGLE_TYPE_ANGLE 0x3203
#define EGL_PLATFORM_ANGLE_MAX_VERSION_MAJOR_ANGLE 0x3204
#define EGL_PLATFORM_ANGLE_MAX_VERSION_MINOR_ANGLE 0x3205
#define EGL_PLATFORM_ANGLE_TYPE_DEFAULT_ANGLE 0x3206
#endif /* EGL_ANGLE_platform_angle */

#ifndef EGL_ANGLE_platform_angle_d3d
#define EGL_ANGLE_platform_angle_d3d 1
#define EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE 0x3207
#define EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE 0x3208
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE 0x3209
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_HARDWARE_ANGLE 0x320A
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE 0x320B
#define EGL_PLATFORM_ANGLE_DEVICE_TYPE_REFERENCE_ANGLE 0x320C
#endif /* EGL_ANGLE_platform_angle_d3d */

#ifndef EGL_ANGLE_platform_angle_opengl
#define EGL_ANGLE_platform_angle_opengl 1
#define EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE 0x320D
#define EGL_PLATFORM_ANGLE_TYPE_OPENGLES_ANGLE 0x320E
#endif /* EGL_ANGLE_platform_angle_opengl */

#ifndef EGL_ANGLE_platform_angle_null
#define EGL_ANGLE_platform_angle_null 1
#define EGL_PLATFORM_ANGLE_TYPE_NULL_ANGLE 0x33AE
#endif /* EGL_ANGLE_platform_angle_null */

#ifndef EGL_ANGLE_x11_visual
#define EGL_ANGLE_x11_visual 1
#define EGL_X11_VISUAL_ID_ANGLE 0x33A3
#endif /* EGL_ANGLE_x11_visual */

#ifndef EGL_ANGLE_surface_orientation
#define EGL_ANGLE_surface_orientation
#define EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE 0x33A7
#define EGL_SURFACE_ORIENTATION_ANGLE 0x33A8
#define EGL_SURFACE_ORIENTATION_INVERT_X_ANGLE 0x0001
#define EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE 0x0002
#endif /* EGL_ANGLE_surface_orientation */

#ifndef EGL_ANGLE_direct_composition
#define EGL_ANGLE_direct_composition 1
#define EGL_DIRECT_COMPOSITION_ANGLE 0x33A5
#endif /* EGL_ANGLE_direct_composition */

#ifndef EGL_ANGLE_flexible_surface_compatibility
#define EGL_ANGLE_flexible_surface_compatibility 1
#define EGL_FLEXIBLE_SURFACE_COMPATIBILITY_SUPPORTED_ANGLE 0x33A6
#endif /* EGL_ANGLE_flexible_surface_compatibility */

using ui::GetLastEGLErrorString;

namespace gl {

bool GLSurfaceEGL::initialized_ = false;

namespace {

EGLDisplay g_display = EGL_NO_DISPLAY;
EGLNativeDisplayType g_native_display = EGL_DEFAULT_DISPLAY;

const char* g_egl_extensions = nullptr;
bool g_egl_create_context_robustness_supported = false;
bool g_egl_create_context_bind_generates_resource_supported = false;
bool g_egl_create_context_webgl_compatability_supported = false;
bool g_egl_sync_control_supported = false;
bool g_egl_window_fixed_size_supported = false;
bool g_egl_surfaceless_context_supported = false;
bool g_egl_surface_orientation_supported = false;
bool g_egl_context_priority_supported = false;
bool g_use_direct_composition = false;

class EGLSyncControlVSyncProvider : public SyncControlVSyncProvider {
 public:
  explicit EGLSyncControlVSyncProvider(EGLSurface surface)
      : SyncControlVSyncProvider(),
        surface_(surface) {
  }

  ~EGLSyncControlVSyncProvider() override {}

  static bool IsSupported() {
    return SyncControlVSyncProvider::IsSupported() &&
           g_egl_sync_control_supported;
  }

 protected:
  bool GetSyncValues(int64_t* system_time,
                     int64_t* media_stream_counter,
                     int64_t* swap_buffer_counter) override {
    uint64_t u_system_time, u_media_stream_counter, u_swap_buffer_counter;
    bool result = eglGetSyncValuesCHROMIUM(
        g_display, surface_, &u_system_time,
        &u_media_stream_counter, &u_swap_buffer_counter) == EGL_TRUE;
    if (result) {
      *system_time = static_cast<int64_t>(u_system_time);
      *media_stream_counter = static_cast<int64_t>(u_media_stream_counter);
      *swap_buffer_counter = static_cast<int64_t>(u_swap_buffer_counter);
    }
    return result;
  }

  bool GetMscRate(int32_t* numerator, int32_t* denominator) override {
    return false;
  }

 private:
  EGLSurface surface_;

  DISALLOW_COPY_AND_ASSIGN(EGLSyncControlVSyncProvider);
};

EGLDisplay GetPlatformANGLEDisplay(EGLNativeDisplayType native_display,
                                   EGLenum platform_type,
                                   bool warpDevice) {
  std::vector<EGLint> display_attribs;

  display_attribs.push_back(EGL_PLATFORM_ANGLE_TYPE_ANGLE);
  display_attribs.push_back(platform_type);

  if (warpDevice) {
    display_attribs.push_back(EGL_PLATFORM_ANGLE_DEVICE_TYPE_ANGLE);
    display_attribs.push_back(EGL_PLATFORM_ANGLE_DEVICE_TYPE_WARP_ANGLE);
  }

#if defined(USE_X11) && !defined(OS_CHROMEOS)
  // ANGLE_NULL doesn't use the visual, and may run without X11 where we can't
  // get it anyway.
  if (platform_type != EGL_PLATFORM_ANGLE_TYPE_NULL_ANGLE) {
    Visual* visual;
    ui::XVisualManager::GetInstance()->ChooseVisualForWindow(
        true, &visual, nullptr, nullptr, nullptr);
    display_attribs.push_back(EGL_X11_VISUAL_ID_ANGLE);
    display_attribs.push_back(static_cast<EGLint>(XVisualIDFromVisual(visual)));
  }
#endif

  display_attribs.push_back(EGL_NONE);

  return eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE,
                                  reinterpret_cast<void*>(native_display),
                                  &display_attribs[0]);
}

EGLDisplay GetDisplayFromType(DisplayType display_type,
                              EGLNativeDisplayType native_display) {
  switch (display_type) {
    case DEFAULT:
    case SWIFT_SHADER:
      return eglGetDisplay(native_display);
    case ANGLE_D3D9:
      return GetPlatformANGLEDisplay(native_display,
                                     EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE, false);
    case ANGLE_D3D11:
      return GetPlatformANGLEDisplay(
          native_display, EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE, false);
    case ANGLE_OPENGL:
      return GetPlatformANGLEDisplay(
          native_display, EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE, false);
    case ANGLE_OPENGLES:
      return GetPlatformANGLEDisplay(
          native_display, EGL_PLATFORM_ANGLE_TYPE_OPENGLES_ANGLE, false);
    case ANGLE_NULL:
      return GetPlatformANGLEDisplay(native_display,
                                     EGL_PLATFORM_ANGLE_TYPE_NULL_ANGLE, false);
    default:
      NOTREACHED();
      return EGL_NO_DISPLAY;
  }
}

const char* DisplayTypeString(DisplayType display_type) {
  switch (display_type) {
    case DEFAULT:
      return "Default";
    case SWIFT_SHADER:
      return "SwiftShader";
    case ANGLE_D3D9:
      return "D3D9";
    case ANGLE_D3D11:
      return "D3D11";
    case ANGLE_OPENGL:
      return "OpenGL";
    case ANGLE_OPENGLES:
      return "OpenGLES";
    case ANGLE_NULL:
      return "Null";
    default:
      NOTREACHED();
      return "Err";
  }
}

bool ValidateEglConfig(EGLDisplay display,
                       const EGLint* config_attribs,
                       EGLint* num_configs) {
  if (!eglChooseConfig(display,
                       config_attribs,
                       NULL,
                       0,
                       num_configs)) {
    LOG(ERROR) << "eglChooseConfig failed with error "
               << GetLastEGLErrorString();
    return false;
  }
  if (*num_configs == 0) {
    return false;
  }
  return true;
}

EGLConfig ChooseConfig(GLSurfaceFormat format, bool surfaceless) {
  // Choose an EGL configuration.
  // On X this is only used for PBuffer surfaces.

  std::vector<EGLint> renderable_types;
  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kDisableES3GLContext)) {
    renderable_types.push_back(EGL_OPENGL_ES3_BIT);
  }
  renderable_types.push_back(EGL_OPENGL_ES2_BIT);

  EGLint buffer_size = format.GetBufferSize();
  EGLint alpha_size = 8;
  bool want_rgb565 = buffer_size == 16;
  EGLint depth_size = format.GetDepthBits();
  EGLint stencil_size = format.GetStencilBits();
  EGLint samples = format.GetSamples();

#if defined(USE_X11) && !defined(OS_CHROMEOS)
  // If we're using ANGLE_NULL, we may not have a display, in which case we
  // can't use XVisualManager.
  if (g_native_display) {
    ui::XVisualManager::GetInstance()->ChooseVisualForWindow(
        true, nullptr, &buffer_size, nullptr, nullptr);
    alpha_size = buffer_size == 32 ? 8 : 0;
  }
#endif

  EGLint surface_type =
      (surfaceless ? EGL_DONT_CARE : EGL_WINDOW_BIT | EGL_PBUFFER_BIT);

  for (auto renderable_type : renderable_types) {
    EGLint config_attribs_8888[] = {EGL_BUFFER_SIZE,
                                    buffer_size,
                                    EGL_ALPHA_SIZE,
                                    alpha_size,
                                    EGL_BLUE_SIZE,
                                    8,
                                    EGL_GREEN_SIZE,
                                    8,
                                    EGL_RED_SIZE,
                                    8,
                                    EGL_SAMPLES,
                                    samples,
                                    EGL_DEPTH_SIZE,
                                    depth_size,
                                    EGL_STENCIL_SIZE,
                                    stencil_size,
                                    EGL_RENDERABLE_TYPE,
                                    renderable_type,
                                    EGL_SURFACE_TYPE,
                                    surface_type,
                                    EGL_NONE};

    EGLint config_attribs_565[] = {EGL_BUFFER_SIZE,
                                   16,
                                   EGL_BLUE_SIZE,
                                   5,
                                   EGL_GREEN_SIZE,
                                   6,
                                   EGL_RED_SIZE,
                                   5,
                                   EGL_SAMPLES,
                                   samples,
                                   EGL_DEPTH_SIZE,
                                   depth_size,
                                   EGL_STENCIL_SIZE,
                                   stencil_size,
                                   EGL_RENDERABLE_TYPE,
                                   renderable_type,
                                   EGL_SURFACE_TYPE,
                                   surface_type,
                                   EGL_NONE};

    EGLint* choose_attributes = config_attribs_8888;
    if (want_rgb565) {
      choose_attributes = config_attribs_565;
    }

    EGLint num_configs;
    EGLint config_size = 1;
    EGLConfig config = nullptr;
    EGLConfig* config_data = &config;
    // Validate if there are any configs for given attribs.
    if (!ValidateEglConfig(g_display, choose_attributes, &num_configs)) {
      // Try the next renderable_type
      continue;
    }

    std::unique_ptr<EGLConfig[]> matching_configs(new EGLConfig[num_configs]);
    if (want_rgb565) {
      config_size = num_configs;
      config_data = matching_configs.get();
    }

    if (!eglChooseConfig(g_display, choose_attributes, config_data, config_size,
                         &num_configs)) {
      LOG(ERROR) << "eglChooseConfig failed with error "
                 << GetLastEGLErrorString();
      return config;
    }

    if (want_rgb565) {
      // Because of the EGL config sort order, we have to iterate
      // through all of them (it'll put higher sum(R,G,B) bits
      // first with the above attribs).
      bool match_found = false;
      for (int i = 0; i < num_configs; i++) {
        EGLint red, green, blue, alpha;
        // Read the relevant attributes of the EGLConfig.
        if (eglGetConfigAttrib(g_display, matching_configs[i], EGL_RED_SIZE,
                               &red) &&
            eglGetConfigAttrib(g_display, matching_configs[i], EGL_BLUE_SIZE,
                               &blue) &&
            eglGetConfigAttrib(g_display, matching_configs[i], EGL_GREEN_SIZE,
                               &green) &&
            eglGetConfigAttrib(g_display, matching_configs[i], EGL_ALPHA_SIZE,
                               &alpha) &&
            alpha == 0 && red == 5 && green == 6 && blue == 5) {
          config = matching_configs[i];
          match_found = true;
          break;
        }
      }
      if (!match_found) {
        // To fall back to default 32 bit format, choose with
        // the right attributes again.
        if (!ValidateEglConfig(g_display, config_attribs_8888, &num_configs)) {
          // Try the next renderable_type
          continue;
        }
        if (!eglChooseConfig(g_display, config_attribs_8888, &config, 1,
                             &num_configs)) {
          LOG(ERROR) << "eglChooseConfig failed with error "
                     << GetLastEGLErrorString();
          return config;
        }
      }
    }
    return config;
  }

  LOG(ERROR) << "No suitable EGL configs found.";
  return nullptr;
}

}  // namespace

void GetEGLInitDisplays(bool supports_angle_d3d,
                        bool supports_angle_opengl,
                        bool supports_angle_null,
                        const base::CommandLine* command_line,
                        std::vector<DisplayType>* init_displays) {
  // SwiftShader does not use the platform extensions
  if (command_line->GetSwitchValueASCII(switches::kUseGL) ==
      kGLImplementationSwiftShaderForWebGLName) {
    init_displays->push_back(SWIFT_SHADER);
    return;
  }

  std::string requested_renderer =
      command_line->GetSwitchValueASCII(switches::kUseANGLE);

  bool use_angle_default =
      !command_line->HasSwitch(switches::kUseANGLE) ||
      requested_renderer == kANGLEImplementationDefaultName;

  if (supports_angle_null &&
      requested_renderer == kANGLEImplementationNullName) {
    init_displays->push_back(ANGLE_NULL);
    return;
  }

  if (supports_angle_d3d) {
    if (use_angle_default) {
      // Default mode for ANGLE - try D3D11, else try D3D9
      if (!command_line->HasSwitch(switches::kDisableD3D11)) {
        init_displays->push_back(ANGLE_D3D11);
      }
      init_displays->push_back(ANGLE_D3D9);
    } else {
      if (requested_renderer == kANGLEImplementationD3D11Name) {
        init_displays->push_back(ANGLE_D3D11);
      }
      if (requested_renderer == kANGLEImplementationD3D9Name) {
        init_displays->push_back(ANGLE_D3D9);
      }
    }
  }

  if (supports_angle_opengl) {
    if (use_angle_default && !supports_angle_d3d) {
      init_displays->push_back(ANGLE_OPENGL);
      init_displays->push_back(ANGLE_OPENGLES);
    } else {
      if (requested_renderer == kANGLEImplementationOpenGLName) {
        init_displays->push_back(ANGLE_OPENGL);
      }
      if (requested_renderer == kANGLEImplementationOpenGLESName) {
        init_displays->push_back(ANGLE_OPENGLES);
      }
    }
  }

  // If no displays are available due to missing angle extensions or invalid
  // flags, request the default display.
  if (init_displays->empty()) {
    init_displays->push_back(DEFAULT);
  }
}

GLSurfaceEGL::GLSurfaceEGL() {}

GLSurfaceFormat GLSurfaceEGL::GetFormat() {
  return format_;
}

EGLDisplay GLSurfaceEGL::GetDisplay() {
  return g_display;
}

EGLConfig GLSurfaceEGL::GetConfig() {
  if (!config_) {
    config_ = ChooseConfig(format_, IsSurfaceless());
  }
  return config_;
}

// static
bool GLSurfaceEGL::InitializeOneOff(EGLNativeDisplayType native_display) {
  if (initialized_)
    return true;

  // Must be called before InitializeDisplay().
  g_driver_egl.InitializeClientExtensionBindings();

  InitializeDisplay(native_display);
  if (g_display == EGL_NO_DISPLAY)
    return false;

  // Must be called after InitializeDisplay().
  g_driver_egl.InitializeExtensionBindings();

  g_egl_extensions = eglQueryString(g_display, EGL_EXTENSIONS);
  g_egl_create_context_robustness_supported =
      HasEGLExtension("EGL_EXT_create_context_robustness");
  g_egl_create_context_bind_generates_resource_supported =
      HasEGLExtension("EGL_CHROMIUM_create_context_bind_generates_resource");
  g_egl_create_context_webgl_compatability_supported =
      HasEGLExtension("EGL_ANGLE_create_context_webgl_compatibility");
  g_egl_sync_control_supported =
      HasEGLExtension("EGL_CHROMIUM_sync_control");
  g_egl_window_fixed_size_supported =
      HasEGLExtension("EGL_ANGLE_window_fixed_size");
  g_egl_surface_orientation_supported =
      HasEGLExtension("EGL_ANGLE_surface_orientation");
  // According to https://source.android.com/compatibility/android-cdd.html the
  // EGL_IMG_context_priority extension is mandatory for Virtual Reality High
  // Performance support, but due to a bug in Android Nougat the extension
  // isn't being reported even when it's present. As a fallback, check if other
  // related extensions that were added for VR support are present, and assume
  // that this implies context priority is also supported. See also:
  // https://github.com/googlevr/gvr-android-sdk/issues/330
  g_egl_context_priority_supported =
      HasEGLExtension("EGL_IMG_context_priority") ||
      (HasEGLExtension("EGL_ANDROID_front_buffer_auto_refresh") &&
       HasEGLExtension("EGL_ANDROID_create_native_client_buffer"));

  // Need EGL_ANGLE_flexible_surface_compatibility to allow surfaces with and
  // without alpha to be bound to the same context.
  g_use_direct_composition =
      HasEGLExtension("EGL_ANGLE_direct_composition") &&
      HasEGLExtension("EGL_ANGLE_flexible_surface_compatibility") &&
      !base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kDisableDirectComposition);

  // TODO(oetuaho@nvidia.com): Surfaceless is disabled on Android as a temporary
  // workaround, since code written for Android WebView takes different paths
  // based on whether GL surface objects have underlying EGL surface handles,
  // conflicting with the use of surfaceless. See https://crbug.com/382349
#if defined(OS_ANDROID)
  DCHECK(!g_egl_surfaceless_context_supported);
#else
  // Check if SurfacelessEGL is supported.
  g_egl_surfaceless_context_supported =
      HasEGLExtension("EGL_KHR_surfaceless_context");
  if (g_egl_surfaceless_context_supported) {
    // EGL_KHR_surfaceless_context is supported but ensure
    // GL_OES_surfaceless_context is also supported. We need a current context
    // to query for supported GL extensions.
    scoped_refptr<GLSurface> surface = new SurfacelessEGL(gfx::Size(1, 1));
    scoped_refptr<GLContext> context = InitializeGLContext(
        new GLContextEGL(nullptr), surface.get(), GLContextAttribs());
    if (!context->MakeCurrent(surface.get()))
      g_egl_surfaceless_context_supported = false;

    // Ensure context supports GL_OES_surfaceless_context.
    if (g_egl_surfaceless_context_supported) {
      g_egl_surfaceless_context_supported = context->HasExtension(
          "GL_OES_surfaceless_context");
      context->ReleaseCurrent(surface.get());
    }
  }
#endif
  initialized_ = true;

  return true;
}

// static
void GLSurfaceEGL::ShutdownOneOff() {
  ResetANGLEPlatform(g_display);

  if (g_display != EGL_NO_DISPLAY)
    eglTerminate(g_display);
  g_display = EGL_NO_DISPLAY;

  g_egl_extensions = nullptr;
  g_egl_create_context_robustness_supported = false;
  g_egl_create_context_bind_generates_resource_supported = false;
  g_egl_create_context_webgl_compatability_supported = false;
  g_egl_sync_control_supported = false;
  g_egl_window_fixed_size_supported = false;
  g_egl_surface_orientation_supported = false;
  g_use_direct_composition = false;
  g_egl_surfaceless_context_supported = false;

  initialized_ = false;
}

// static
EGLDisplay GLSurfaceEGL::GetHardwareDisplay() {
  return g_display;
}

// static
EGLNativeDisplayType GLSurfaceEGL::GetNativeDisplay() {
  return g_native_display;
}

// static
const char* GLSurfaceEGL::GetEGLExtensions() {
  return g_egl_extensions;
}

// static
bool GLSurfaceEGL::HasEGLExtension(const char* name) {
  return ExtensionsContain(GetEGLExtensions(), name);
}

// static
bool GLSurfaceEGL::IsCreateContextRobustnessSupported() {
  return g_egl_create_context_robustness_supported;
}

bool GLSurfaceEGL::IsCreateContextBindGeneratesResourceSupported() {
  return g_egl_create_context_bind_generates_resource_supported;
}

bool GLSurfaceEGL::IsCreateContextWebGLCompatabilitySupported() {
  return g_egl_create_context_webgl_compatability_supported;
}

// static
bool GLSurfaceEGL::IsEGLSurfacelessContextSupported() {
  return g_egl_surfaceless_context_supported;
}

// static
bool GLSurfaceEGL::IsEGLContextPrioritySupported() {
  return g_egl_context_priority_supported;
}

// static
bool GLSurfaceEGL::IsDirectCompositionSupported() {
  return g_use_direct_composition;
}

GLSurfaceEGL::~GLSurfaceEGL() {}

// InitializeDisplay is necessary because the static binding code
// needs a full Display init before it can query the Display extensions.
// static
EGLDisplay GLSurfaceEGL::InitializeDisplay(
    EGLNativeDisplayType native_display) {
  if (g_display != EGL_NO_DISPLAY) {
    return g_display;
  }

  g_native_display = native_display;

  // If EGL_EXT_client_extensions not supported this call to eglQueryString
  // will return NULL.
  const char* client_extensions =
      eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);

  bool supports_angle_d3d = false;
  bool supports_angle_opengl = false;
  bool supports_angle_null = false;
  // Check for availability of ANGLE extensions.
  if (client_extensions &&
      ExtensionsContain(client_extensions, "EGL_ANGLE_platform_angle")) {
    supports_angle_d3d =
        ExtensionsContain(client_extensions, "EGL_ANGLE_platform_angle_d3d");
    supports_angle_opengl =
        ExtensionsContain(client_extensions, "EGL_ANGLE_platform_angle_opengl");
    supports_angle_null =
        ExtensionsContain(client_extensions, "EGL_ANGLE_platform_angle_null");
  }

  std::vector<DisplayType> init_displays;
  GetEGLInitDisplays(supports_angle_d3d, supports_angle_opengl,
                     supports_angle_null,
                     base::CommandLine::ForCurrentProcess(), &init_displays);

  for (size_t disp_index = 0; disp_index < init_displays.size(); ++disp_index) {
    DisplayType display_type = init_displays[disp_index];
    EGLDisplay display =
        GetDisplayFromType(display_type, g_native_display);
    if (display == EGL_NO_DISPLAY) {
      LOG(ERROR) << "EGL display query failed with error "
                 << GetLastEGLErrorString();
    }

    // Init ANGLE platform now that we have the global display.
    if (supports_angle_d3d || supports_angle_opengl || supports_angle_null) {
      if (!InitializeANGLEPlatform(display)) {
        LOG(ERROR) << "ANGLE Platform initialization failed.";
      }
    }

    if (!eglInitialize(display, nullptr, nullptr)) {
      bool is_last = disp_index == init_displays.size() - 1;

      LOG(ERROR) << "eglInitialize " << DisplayTypeString(display_type)
                 << " failed with error " << GetLastEGLErrorString()
                 << (is_last ? "" : ", trying next display type");
    } else {
      UMA_HISTOGRAM_ENUMERATION("GPU.EGLDisplayType", display_type,
                                DISPLAY_TYPE_MAX);
      g_display = display;
      break;
    }
  }

  return g_display;
}

NativeViewGLSurfaceEGL::NativeViewGLSurfaceEGL(
    EGLNativeWindowType window,
    std::unique_ptr<gfx::VSyncProvider> vsync_provider)
    : window_(window),
      size_(1, 1),
      enable_fixed_size_angle_(false),
      surface_(NULL),
      supports_post_sub_buffer_(false),
      supports_swap_buffer_with_damage_(false),
      flips_vertically_(false),
      vsync_provider_external_(std::move(vsync_provider)) {
#if defined(OS_ANDROID)
  if (window)
    ANativeWindow_acquire(window);
#endif

#if defined(OS_WIN)
  RECT windowRect;
  if (GetClientRect(window_, &windowRect))
    size_ = gfx::Rect(windowRect).size();
#endif
}

bool NativeViewGLSurfaceEGL::Initialize(GLSurfaceFormat format) {
  DCHECK(!surface_);
  format_ = format;

  if (!GetDisplay()) {
    LOG(ERROR) << "Trying to create surface with invalid display.";
    return false;
  }

  // We need to make sure that window_ is correctly initialized with all
  // the platform-dependant quirks, if any, before creating the surface.
  if (!InitializeNativeWindow()) {
    LOG(ERROR) << "Error trying to initialize the native window.";
    return false;
  }

  std::vector<EGLint> egl_window_attributes;

  if (g_egl_window_fixed_size_supported && enable_fixed_size_angle_) {
    egl_window_attributes.push_back(EGL_FIXED_SIZE_ANGLE);
    egl_window_attributes.push_back(EGL_TRUE);
    egl_window_attributes.push_back(EGL_WIDTH);
    egl_window_attributes.push_back(size_.width());
    egl_window_attributes.push_back(EGL_HEIGHT);
    egl_window_attributes.push_back(size_.height());
  }

  if (g_driver_egl.ext.b_EGL_NV_post_sub_buffer) {
    egl_window_attributes.push_back(EGL_POST_SUB_BUFFER_SUPPORTED_NV);
    egl_window_attributes.push_back(EGL_TRUE);
  }

  if (g_egl_surface_orientation_supported) {
    EGLint attrib;
    eglGetConfigAttrib(GetDisplay(), GetConfig(),
                       EGL_OPTIMAL_SURFACE_ORIENTATION_ANGLE, &attrib);
    flips_vertically_ = (attrib == EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE);
  }

  if (flips_vertically_) {
    egl_window_attributes.push_back(EGL_SURFACE_ORIENTATION_ANGLE);
    egl_window_attributes.push_back(EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE);
  }

  if (g_use_direct_composition) {
    egl_window_attributes.push_back(
        EGL_FLEXIBLE_SURFACE_COMPATIBILITY_SUPPORTED_ANGLE);
    egl_window_attributes.push_back(EGL_TRUE);
    egl_window_attributes.push_back(EGL_DIRECT_COMPOSITION_ANGLE);
    egl_window_attributes.push_back(EGL_TRUE);
  }

  egl_window_attributes.push_back(EGL_NONE);
  // Create a surface for the native window.
  surface_ = eglCreateWindowSurface(
      GetDisplay(), GetConfig(), window_, &egl_window_attributes[0]);

  if (!surface_) {
    LOG(ERROR) << "eglCreateWindowSurface failed with error "
               << GetLastEGLErrorString();
    Destroy();
    return false;
  }

  if (g_driver_egl.ext.b_EGL_NV_post_sub_buffer) {
    EGLint surfaceVal;
    EGLBoolean retVal = eglQuerySurface(
        GetDisplay(), surface_, EGL_POST_SUB_BUFFER_SUPPORTED_NV, &surfaceVal);
    supports_post_sub_buffer_ = (surfaceVal && retVal) == EGL_TRUE;
  }

  supports_swap_buffer_with_damage_ =
      g_driver_egl.ext.b_EGL_KHR_swap_buffers_with_damage;

  if (!vsync_provider_external_ && EGLSyncControlVSyncProvider::IsSupported()) {
    vsync_provider_internal_ =
        base::MakeUnique<EGLSyncControlVSyncProvider>(surface_);
  }
  return true;
}

bool NativeViewGLSurfaceEGL::InitializeNativeWindow() {
  return true;
}

void NativeViewGLSurfaceEGL::Destroy() {
  vsync_provider_internal_ = nullptr;

  if (surface_) {
    if (!eglDestroySurface(GetDisplay(), surface_)) {
      LOG(ERROR) << "eglDestroySurface failed with error "
                 << GetLastEGLErrorString();
    }
    surface_ = NULL;
  }
}

bool NativeViewGLSurfaceEGL::IsOffscreen() {
  return false;
}

gfx::SwapResult NativeViewGLSurfaceEGL::SwapBuffers() {
  TRACE_EVENT2("gpu", "NativeViewGLSurfaceEGL:RealSwapBuffers",
      "width", GetSize().width(),
      "height", GetSize().height());

  if (!CommitAndClearPendingOverlays()) {
    DVLOG(1) << "Failed to commit pending overlay planes.";
    return gfx::SwapResult::SWAP_FAILED;
  }

  if (!eglSwapBuffers(GetDisplay(), surface_)) {
    DVLOG(1) << "eglSwapBuffers failed with error "
             << GetLastEGLErrorString();
    return gfx::SwapResult::SWAP_FAILED;
  }

  return gfx::SwapResult::SWAP_ACK;
}

gfx::Size NativeViewGLSurfaceEGL::GetSize() {
  EGLint width;
  EGLint height;
  if (!eglQuerySurface(GetDisplay(), surface_, EGL_WIDTH, &width) ||
      !eglQuerySurface(GetDisplay(), surface_, EGL_HEIGHT, &height)) {
    NOTREACHED() << "eglQuerySurface failed with error "
                 << GetLastEGLErrorString();
    return gfx::Size();
  }

  return gfx::Size(width, height);
}

bool NativeViewGLSurfaceEGL::Resize(const gfx::Size& size,
                                    float scale_factor,
                                    bool has_alpha) {
  if (size == GetSize())
    return true;

  size_ = size;

  std::unique_ptr<ui::ScopedMakeCurrent> scoped_make_current;
  GLContext* current_context = GLContext::GetCurrent();
  bool was_current =
      current_context && current_context->IsCurrent(this);
  if (was_current) {
    scoped_make_current.reset(
        new ui::ScopedMakeCurrent(current_context, this));
    current_context->ReleaseCurrent(this);
  }

  Destroy();

  if (!Initialize(format_)) {
    LOG(ERROR) << "Failed to resize window.";
    return false;
  }

  return true;
}

bool NativeViewGLSurfaceEGL::Recreate() {
  Destroy();
  if (!Initialize(format_)) {
    LOG(ERROR) << "Failed to create surface.";
    return false;
  }
  return true;
}

EGLSurface NativeViewGLSurfaceEGL::GetHandle() {
  return surface_;
}

bool NativeViewGLSurfaceEGL::SupportsPostSubBuffer() {
  return supports_post_sub_buffer_;
}

bool NativeViewGLSurfaceEGL::FlipsVertically() const {
  return flips_vertically_;
}

bool NativeViewGLSurfaceEGL::BuffersFlipped() const {
  return g_use_direct_composition;
}

gfx::SwapResult NativeViewGLSurfaceEGL::SwapBuffersWithDamage(
    const std::vector<int>& rects) {
  DCHECK(supports_swap_buffer_with_damage_);
  if (!CommitAndClearPendingOverlays()) {
    DVLOG(1) << "Failed to commit pending overlay planes.";
    return gfx::SwapResult::SWAP_FAILED;
  }

  if (!eglSwapBuffersWithDamageKHR(GetDisplay(), surface_,
                                   const_cast<EGLint*>(rects.data()),
                                   static_cast<EGLint>(rects.size() / 4))) {
    DVLOG(1) << "eglSwapBuffersWithDamageKHR failed with error "
             << GetLastEGLErrorString();
    return gfx::SwapResult::SWAP_FAILED;
  }
  return gfx::SwapResult::SWAP_ACK;
}

gfx::SwapResult NativeViewGLSurfaceEGL::PostSubBuffer(int x,
                                                      int y,
                                                      int width,
                                                      int height) {
  DCHECK(supports_post_sub_buffer_);
  if (!CommitAndClearPendingOverlays()) {
    DVLOG(1) << "Failed to commit pending overlay planes.";
    return gfx::SwapResult::SWAP_FAILED;
  }
  if (flips_vertically_) {
    // With EGL_SURFACE_ORIENTATION_INVERT_Y_ANGLE the contents are rendered
    // inverted, but the PostSubBuffer rectangle is still measured from the
    // bottom left.
    y = GetSize().height() - y - height;
  }
  if (!eglPostSubBufferNV(GetDisplay(), surface_, x, y, width, height)) {
    DVLOG(1) << "eglPostSubBufferNV failed with error "
             << GetLastEGLErrorString();
    return gfx::SwapResult::SWAP_FAILED;
  }
  return gfx::SwapResult::SWAP_ACK;
}

bool NativeViewGLSurfaceEGL::SupportsCommitOverlayPlanes() {
#if defined(OS_ANDROID)
  return true;
#else
  return false;
#endif
}

gfx::SwapResult NativeViewGLSurfaceEGL::CommitOverlayPlanes() {
  DCHECK(SupportsCommitOverlayPlanes());
  // Here we assume that the overlays scheduled on this surface will display
  // themselves to the screen right away in |CommitAndClearPendingOverlays|,
  // rather than being queued and waiting for a "swap" signal.
  return CommitAndClearPendingOverlays() ? gfx::SwapResult::SWAP_ACK
                                         : gfx::SwapResult::SWAP_FAILED;
}

gfx::VSyncProvider* NativeViewGLSurfaceEGL::GetVSyncProvider() {
  return vsync_provider_external_ ? vsync_provider_external_.get()
                                  : vsync_provider_internal_.get();
}

bool NativeViewGLSurfaceEGL::ScheduleOverlayPlane(
    int z_order,
    gfx::OverlayTransform transform,
    GLImage* image,
    const gfx::Rect& bounds_rect,
    const gfx::RectF& crop_rect) {
#if !defined(OS_ANDROID)
  NOTIMPLEMENTED();
  return false;
#else
  pending_overlays_.push_back(
      GLSurfaceOverlay(z_order, transform, image, bounds_rect, crop_rect));
  return true;
#endif
}

NativeViewGLSurfaceEGL::~NativeViewGLSurfaceEGL() {
  Destroy();
#if defined(OS_ANDROID)
  if (window_)
    ANativeWindow_release(window_);
#endif
}

bool NativeViewGLSurfaceEGL::CommitAndClearPendingOverlays() {
  if (pending_overlays_.empty())
    return true;

  bool success = true;
  for (const auto& overlay : pending_overlays_)
    success &= overlay.ScheduleOverlayPlane(window_);
  pending_overlays_.clear();
  return success;
}

PbufferGLSurfaceEGL::PbufferGLSurfaceEGL(const gfx::Size& size)
    : size_(size),
      surface_(NULL) {
  // Some implementations of Pbuffer do not support having a 0 size. For such
  // cases use a (1, 1) surface.
  if (size_.GetArea() == 0)
    size_.SetSize(1, 1);
}

bool PbufferGLSurfaceEGL::Initialize(GLSurfaceFormat format) {
  EGLSurface old_surface = surface_;

#if defined(OS_ANDROID)
  // This is to allow context virtualization which requires on- and offscreen
  // to use a compatible config. We expect the client to request RGB565
  // onscreen surface also for this to work (with the exception of
  // fullscreen video).
  if (base::SysInfo::AmountOfPhysicalMemoryMB() <= 512)
    format.SetRGB565();
#endif

  format_ = format;

  EGLDisplay display = GetDisplay();
  if (!display) {
    LOG(ERROR) << "Trying to create surface with invalid display.";
    return false;
  }

  // Allocate the new pbuffer surface before freeing the old one to ensure
  // they have different addresses. If they have the same address then a
  // future call to MakeCurrent might early out because it appears the current
  // context and surface have not changed.
  std::vector<EGLint> pbuffer_attribs;
  pbuffer_attribs.push_back(EGL_WIDTH);
  pbuffer_attribs.push_back(size_.width());
  pbuffer_attribs.push_back(EGL_HEIGHT);
  pbuffer_attribs.push_back(size_.height());

  if (g_use_direct_composition) {
    pbuffer_attribs.push_back(
        EGL_FLEXIBLE_SURFACE_COMPATIBILITY_SUPPORTED_ANGLE);
    pbuffer_attribs.push_back(EGL_TRUE);
  }

  pbuffer_attribs.push_back(EGL_NONE);

  EGLSurface new_surface =
      eglCreatePbufferSurface(display, GetConfig(), &pbuffer_attribs[0]);
  if (!new_surface) {
    LOG(ERROR) << "eglCreatePbufferSurface failed with error "
               << GetLastEGLErrorString();
    return false;
  }

  if (old_surface)
    eglDestroySurface(display, old_surface);

  surface_ = new_surface;
  return true;
}

void PbufferGLSurfaceEGL::Destroy() {
  if (surface_) {
    if (!eglDestroySurface(GetDisplay(), surface_)) {
      LOG(ERROR) << "eglDestroySurface failed with error "
                 << GetLastEGLErrorString();
    }
    surface_ = NULL;
  }
}

bool PbufferGLSurfaceEGL::IsOffscreen() {
  return true;
}

gfx::SwapResult PbufferGLSurfaceEGL::SwapBuffers() {
  NOTREACHED() << "Attempted to call SwapBuffers on a PbufferGLSurfaceEGL.";
  return gfx::SwapResult::SWAP_FAILED;
}

gfx::Size PbufferGLSurfaceEGL::GetSize() {
  return size_;
}

bool PbufferGLSurfaceEGL::Resize(const gfx::Size& size,
                                 float scale_factor,
                                 bool has_alpha) {
  if (size == size_)
    return true;

  std::unique_ptr<ui::ScopedMakeCurrent> scoped_make_current;
  GLContext* current_context = GLContext::GetCurrent();
  bool was_current =
      current_context && current_context->IsCurrent(this);
  if (was_current) {
    scoped_make_current.reset(
        new ui::ScopedMakeCurrent(current_context, this));
  }

  size_ = size;

  if (!Initialize(format_)) {
    LOG(ERROR) << "Failed to resize pbuffer.";
    return false;
  }

  return true;
}

EGLSurface PbufferGLSurfaceEGL::GetHandle() {
  return surface_;
}

void* PbufferGLSurfaceEGL::GetShareHandle() {
#if defined(OS_ANDROID)
  NOTREACHED();
  return NULL;
#else
  if (!g_driver_egl.ext.b_EGL_ANGLE_query_surface_pointer)
    return NULL;

  if (!g_driver_egl.ext.b_EGL_ANGLE_surface_d3d_texture_2d_share_handle)
    return NULL;

  void* handle;
  if (!eglQuerySurfacePointerANGLE(g_display,
                                   GetHandle(),
                                   EGL_D3D_TEXTURE_2D_SHARE_HANDLE_ANGLE,
                                   &handle)) {
    return NULL;
  }

  return handle;
#endif
}

PbufferGLSurfaceEGL::~PbufferGLSurfaceEGL() {
  Destroy();
}

SurfacelessEGL::SurfacelessEGL(const gfx::Size& size) : size_(size) {}

bool SurfacelessEGL::Initialize(GLSurfaceFormat format) {
  format_ = format;
  return true;
}

void SurfacelessEGL::Destroy() {
}

bool SurfacelessEGL::IsOffscreen() {
  return true;
}

bool SurfacelessEGL::IsSurfaceless() const {
  return true;
}

gfx::SwapResult SurfacelessEGL::SwapBuffers() {
  LOG(ERROR) << "Attempted to call SwapBuffers with SurfacelessEGL.";
  return gfx::SwapResult::SWAP_FAILED;
}

gfx::Size SurfacelessEGL::GetSize() {
  return size_;
}

bool SurfacelessEGL::Resize(const gfx::Size& size,
                            float scale_factor,
                            bool has_alpha) {
  size_ = size;
  return true;
}

EGLSurface SurfacelessEGL::GetHandle() {
  return EGL_NO_SURFACE;
}

void* SurfacelessEGL::GetShareHandle() {
  return NULL;
}

SurfacelessEGL::~SurfacelessEGL() {
}

}  // namespace gl