context.cc

// Copyright (c) 2016 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 "gpu/gles2_conform_support/egl/context.h"

#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/command_line.h"
#include "gpu/command_buffer/client/gles2_implementation.h"
#include "gpu/command_buffer/client/gles2_lib.h"
#include "gpu/command_buffer/client/shared_memory_limits.h"
#include "gpu/command_buffer/client/transfer_buffer.h"
#include "gpu/command_buffer/service/context_group.h"
#include "gpu/command_buffer/service/image_manager.h"
#include "gpu/command_buffer/service/memory_tracking.h"
#include "gpu/command_buffer/service/service_discardable_manager.h"
#include "gpu/command_buffer/service/shared_image_manager.h"
#include "gpu/gles2_conform_support/egl/config.h"
#include "gpu/gles2_conform_support/egl/display.h"
#include "gpu/gles2_conform_support/egl/surface.h"
#include "gpu/gles2_conform_support/egl/thread_state.h"
#include "ui/gl/init/gl_factory.h"

// The slight complexification in this file comes from following properties:
// 1) Command buffer connection (context) can not be established without a
// GLSurface. EGL Context can be created independent of a surface.  This is why
// the connection is created only during first MakeCurrent.
// 2) Command buffer MakeCurrent calls need the real gl context and surface be
// current.
// 3) Client can change real EGL context behind the scenes and then still expect
// command buffer MakeCurrent re-set the command buffer context. This is why all
// MakeCurrent calls must actually reset the real context, even though command
// buffer current context does not change.
// 4) EGL context can be destroyed without surface, but command buffer would
// need the surface to run various cleanups. If context is destroyed
// surfaceless, the context is marked lost before destruction. This is avoided
// if possible, since command buffer at the time of writing prints out debug
// text in this case.

namespace {
const bool kBindGeneratesResources = true;
const bool kLoseContextWhenOutOfMemory = false;
const bool kSupportClientSideArrays = true;
}

namespace gles2_conform_support {
namespace egl {
// static
gpu::GpuFeatureInfo Context::platform_gpu_feature_info_;

// static
void Context::SetPlatformGpuFeatureInfo(
    const gpu::GpuFeatureInfo& gpu_feature_info) {
  platform_gpu_feature_info_ = gpu_feature_info;
}

Context::Context(Display* display, const Config* config)
    : display_(display),
      config_(config),
      is_current_in_some_thread_(false),
      is_destroyed_(false),
      gpu_driver_bug_workarounds_(
          platform_gpu_feature_info_.enabled_gpu_driver_bug_workarounds),
      discardable_manager_(gpu::GpuPreferences()),
      passthrough_discardable_manager_(gpu::GpuPreferences()),
      translator_cache_(gpu::GpuPreferences()) {}

Context::~Context() {
  // We might not have a surface, so we must lose the context.  Cleanup will
  // execute GL commands otherwise. TODO: if shared contexts are ever
  // implemented, this will leak the GL resources. For pbuffer contexts, one
  // could track the last current surface or create a surface for destroying
  // purposes only. Other option would be to make the service usable without
  // surface.
  if (HasService()) {
    if (!WasServiceContextLost())
      MarkServiceContextLost();
    DestroyService();
  }
}

void Context::MarkDestroyed() {
  is_destroyed_ = true;
}

bool Context::SwapBuffers(Surface* current_surface) {
  DCHECK(HasService() && is_current_in_some_thread_);
  if (WasServiceContextLost())
    return false;
  client_gl_context_->SwapBuffers(1);
  return true;
}

bool Context::MakeCurrent(Context* current_context,
                          Surface* current_surface,
                          Context* new_context,
                          Surface* new_surface) {
  if (!new_context && !current_context) {
    return true;
  }
  bool cleanup_old_current_context = false;
  if (current_context) {
    if (current_context->Flush(current_surface->gl_surface()))
      cleanup_old_current_context = new_context != current_context;
  }

  if (new_context) {
    if (!new_context->IsCompatibleSurface(new_surface))
      return false;

    if (new_context->HasService()) {
      if (new_context->WasServiceContextLost())
        return false;
      if (new_context != current_context) {
        // If Flush did not set the current context, set it now. Otherwise
        // calling into the decoder is not ok.
        if (!new_context->gl_context_->MakeCurrent(new_surface->gl_surface())) {
          new_context->MarkServiceContextLost();
          return false;
        }
      }
      if (new_context != current_context || new_surface != current_surface)
        new_context->decoder_->SetSurface(new_surface->gl_surface());
      if (!new_context->decoder_->MakeCurrent()) {
        new_context->MarkServiceContextLost();
        return false;
      }
    } else {
      if (!new_context->CreateService(new_surface->gl_surface())) {
        return false;
      }
    }
  }

  // The current_surface will be released when MakeCurrent succeeds.
  // Cleanup in this case only.
  if (cleanup_old_current_context) {
    if (current_context->is_destroyed_ && current_surface != new_surface) {
      current_context->gl_context_->MakeCurrent(current_surface->gl_surface());
      // If we are releasing the context and we have one ref, it means that the
      // ref will be lost and the object will be destroyed.  Destroy the service
      // explicitly here, so that cleanup can happen and client GL
      // implementation does not print errors.
      current_context->DestroyService();
    } else {
      current_context->decoder_->ReleaseSurface();
    }
  }

  return true;
}

bool Context::ValidateAttributeList(const EGLint* attrib_list) {
  if (attrib_list) {
    for (int i = 0; attrib_list[i] != EGL_NONE; attrib_list += 2) {
      switch (attrib_list[i]) {
        case EGL_CONTEXT_CLIENT_VERSION:
          break;
        default:
          return false;
      }
    }
  }
  return true;
}

void Context::SetGpuControlClient(gpu::GpuControlClient*) {
  // The client is not currently called, so don't store it.
}

const gpu::Capabilities& Context::GetCapabilities() const {
  return capabilities_;
}

void Context::SignalQuery(uint32_t query, base::OnceClosure callback) {
  NOTREACHED();
}

void Context::CreateGpuFence(uint32_t gpu_fence_id, ClientGpuFence source) {
  NOTREACHED();
}

void Context::GetGpuFence(
    uint32_t gpu_fence_id,
    base::OnceCallback<void(std::unique_ptr<gfx::GpuFence>)> callback) {
  NOTREACHED();
}

void Context::SetLock(base::Lock*) {
  NOTREACHED();
}

void Context::EnsureWorkVisible() {
  NOTREACHED();
}

gpu::CommandBufferNamespace Context::GetNamespaceID() const {
  return gpu::CommandBufferNamespace::INVALID;
}

gpu::CommandBufferId Context::GetCommandBufferID() const {
  return gpu::CommandBufferId();
}

void Context::FlushPendingWork() {
  NOTREACHED();
}

uint64_t Context::GenerateFenceSyncRelease() {
  NOTREACHED();
  return 0;
}

bool Context::IsFenceSyncReleased(uint64_t release) {
  NOTREACHED();
  return false;
}

void Context::SignalSyncToken(const gpu::SyncToken& sync_token,
                              base::OnceClosure callback) {
  NOTREACHED();
}

void Context::WaitSyncToken(const gpu::SyncToken& sync_token) {
  NOTREACHED();
}

bool Context::CanWaitUnverifiedSyncToken(const gpu::SyncToken& sync_token) {
  return false;
}

void Context::ApplyCurrentContext(gl::GLSurface* current_surface) {
  DCHECK(HasService());
  // The current_surface will be the same as
  // the surface of the decoder. We can not DCHECK as there is
  // no accessor.
  if (!WasServiceContextLost()) {
    if (!gl_context_->MakeCurrent(current_surface))
      MarkServiceContextLost();
  }
  gles2::SetGLContext(client_gl_context_.get());
}

void Context::ApplyContextReleased() {
  gles2::SetGLContext(nullptr);
}

bool Context::CreateService(gl::GLSurface* gl_surface) {
  gpu::SharedMemoryLimits limits;
  gpu::GpuPreferences gpu_preferences;
  gpu::GpuFeatureInfo gpu_feature_info;
  scoped_refptr<gpu::gles2::FeatureInfo> feature_info(
      new gpu::gles2::FeatureInfo(gpu_driver_bug_workarounds_,
                                  gpu_feature_info));
  scoped_refptr<gpu::gles2::ContextGroup> group(new gpu::gles2::ContextGroup(
      gpu_preferences, true, &mailbox_manager_, nullptr /* memory_tracker */,
      &translator_cache_, &completeness_cache_, feature_info, true,
      &image_manager_, nullptr /* image_factory */,
      nullptr /* progress_reporter */, gpu_feature_info, &discardable_manager_,
      &passthrough_discardable_manager_, &shared_image_manager_));

  auto command_buffer = std::make_unique<gpu::CommandBufferDirect>();

  std::unique_ptr<gpu::gles2::GLES2Decoder> decoder(
      gpu::gles2::GLES2Decoder::Create(command_buffer.get(),
                                       command_buffer->service(), &outputter_,
                                       group.get()));

  command_buffer->set_handler(decoder.get());

  gl::GLContextAttribs context_attribs;
  context_attribs.gpu_preference = gl::GpuPreference::kHighPerformance;
  scoped_refptr<gl::GLContext> gl_context(
      gl::init::CreateGLContext(nullptr, gl_surface, context_attribs));
  if (!gl_context)
    return false;
  platform_gpu_feature_info_.ApplyToGLContext(gl_context.get());

  gl_context->MakeCurrent(gl_surface);

  gpu::ContextCreationAttribs helper;
  config_->GetAttrib(EGL_ALPHA_SIZE, &helper.alpha_size);
  config_->GetAttrib(EGL_DEPTH_SIZE, &helper.depth_size);
  config_->GetAttrib(EGL_STENCIL_SIZE, &helper.stencil_size);

  helper.buffer_preserved = false;
  helper.bind_generates_resource = kBindGeneratesResources;
  helper.fail_if_major_perf_caveat = false;
  helper.lose_context_when_out_of_memory = kLoseContextWhenOutOfMemory;
  helper.context_type = gpu::CONTEXT_TYPE_OPENGLES2;
  helper.offscreen_framebuffer_size = gl_surface->GetSize();

  auto result = decoder->Initialize(gl_surface, gl_context.get(),
                                    gl_surface->IsOffscreen(),
                                    gpu::gles2::DisallowedFeatures(), helper);
  if (result != gpu::ContextResult::kSuccess)
    return false;

  auto gles2_cmd_helper =
      std::make_unique<gpu::gles2::GLES2CmdHelper>(command_buffer.get());
  result = gles2_cmd_helper->Initialize(limits.command_buffer_size);
  if (result != gpu::ContextResult::kSuccess) {
    decoder->Destroy(true);
    return false;
  }
  // Client side Capabilities queries return reference, service side return
  // value. Here two sides are joined together.
  capabilities_ = decoder->GetCapabilities();

  auto transfer_buffer =
      std::make_unique<gpu::TransferBuffer>(gles2_cmd_helper.get());

  gles2_cmd_helper_ = std::move(gles2_cmd_helper);
  transfer_buffer_ = std::move(transfer_buffer);
  command_buffer_ = std::move(command_buffer);
  decoder_ = std::move(decoder);
  gl_context_ = gl_context.get();

  auto context = std::make_unique<gpu::gles2::GLES2Implementation>(
      gles2_cmd_helper_.get(), nullptr, transfer_buffer_.get(),
      kBindGeneratesResources, kLoseContextWhenOutOfMemory,
      kSupportClientSideArrays, this);

  result = context->Initialize(limits);
  if (result != gpu::ContextResult::kSuccess) {
    DestroyService();
    return false;
  }

  context->EnableFeatureCHROMIUM("pepper3d_allow_buffers_on_multiple_targets");
  context->EnableFeatureCHROMIUM("pepper3d_support_fixed_attribs");
  client_gl_context_ = std::move(context);
  return true;
}

void Context::DestroyService() {
  DCHECK(HasService());
  bool have_context = !WasServiceContextLost();
  // The client gl interface might still be set to current global
  // interface. This will be cleaned up in ApplyContextReleased
  // with AutoCurrentContextRestore.
  client_gl_context_.reset();
  gl_context_ = nullptr;

  transfer_buffer_.reset();
  gles2_cmd_helper_.reset();
  if (decoder_)
    decoder_->Destroy(have_context);
  decoder_.reset();
  command_buffer_.reset();
}

bool Context::HasService() const {
  return decoder_ != nullptr;
}

void Context::MarkServiceContextLost() {
  decoder_->GetContextGroup()->LoseContexts(gpu::error::kMakeCurrentFailed);
}

bool Context::WasServiceContextLost() const {
  return decoder_->WasContextLost();
}

bool Context::IsCompatibleSurface(Surface* surface) const {
  // Inspect current_surface->config() instead of gl_surface()->IsOffscreen()
  // because GTF windowless window surfaces might be emulated with offscreen
  // surfaces.
  EGLint value = EGL_NONE;
  config_->GetAttrib(EGL_SURFACE_TYPE, &value);
  bool context_config_is_offscreen = (value & EGL_PBUFFER_BIT) != 0;
  surface->config()->GetAttrib(EGL_SURFACE_TYPE, &value);
  bool surface_config_is_offscreen = (value & EGL_PBUFFER_BIT) != 0;
  return surface_config_is_offscreen == context_config_is_offscreen;
}

bool Context::Flush(gl::GLSurface* gl_surface) {
  if (WasServiceContextLost())
    return false;
  if (!gl_context_->MakeCurrent(gl_surface)) {
    MarkServiceContextLost();
    return false;
  }
  client_gl_context_->Flush();
  return true;
}

}  // namespace egl
}  // namespace gles2_conform_support