// Copyright 2014 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 "mojo/gles2/command_buffer_client_impl.h"

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

#include <limits>
#include <utility>

#include "base/logging.h"
#include "base/process/process_handle.h"
#include "base/threading/thread_restrictions.h"
#include "components/mus/gles2/command_buffer_type_conversions.h"
#include "components/mus/gles2/mojo_buffer_backing.h"
#include "components/mus/gles2/mojo_gpu_memory_buffer.h"
#include "gpu/command_buffer/common/sync_token.h"
#include "gpu/command_buffer/service/image_factory.h"
#include "mojo/platform_handle/platform_handle_functions.h"

namespace gles2 {

namespace {

bool CreateMapAndDupSharedBuffer(size_t size,
                                 void** memory,
                                 mojo::ScopedSharedBufferHandle* handle,
                                 mojo::ScopedSharedBufferHandle* duped) {
  MojoResult result = mojo::CreateSharedBuffer(NULL, size, handle);
  if (result != MOJO_RESULT_OK)
    return false;
  DCHECK(handle->is_valid());

  result = mojo::DuplicateBuffer(handle->get(), NULL, duped);
  if (result != MOJO_RESULT_OK)
    return false;
  DCHECK(duped->is_valid());

  result = mojo::MapBuffer(
      handle->get(), 0, size, memory, MOJO_MAP_BUFFER_FLAG_NONE);
  if (result != MOJO_RESULT_OK)
    return false;
  DCHECK(*memory);

  return true;
}

template <typename T>
void Copy(T* output, T input) {
  *output = std::move(input);
}

}  // namespace

CommandBufferDelegate::~CommandBufferDelegate() {}

void CommandBufferDelegate::ContextLost() {}

CommandBufferClientImpl::CommandBufferClientImpl(
    CommandBufferDelegate* delegate,
    const std::vector<int32_t>& attribs,
    const MojoAsyncWaiter* async_waiter,
    mojo::ScopedMessagePipeHandle command_buffer_handle)
    : delegate_(delegate),
      attribs_(attribs),
      observer_binding_(this),
      command_buffer_id_(0),
      shared_state_(NULL),
      last_put_offset_(-1),
      next_transfer_buffer_id_(0),
      next_image_id_(0),
      next_fence_sync_release_(1),
      flushed_fence_sync_release_(0),
      async_waiter_(async_waiter) {
  command_buffer_.Bind(mojo::InterfacePtrInfo<mus::mojom::CommandBuffer>(
                           std::move(command_buffer_handle), 0u),
                       async_waiter);
  command_buffer_.set_connection_error_handler(
      [this]() { DidLoseContext(gpu::error::kUnknown); });
}

CommandBufferClientImpl::~CommandBufferClientImpl() {}

bool CommandBufferClientImpl::Initialize() {
  const size_t kSharedStateSize = sizeof(gpu::CommandBufferSharedState);
  void* memory = NULL;
  mojo::ScopedSharedBufferHandle duped;
  bool result = CreateMapAndDupSharedBuffer(
      kSharedStateSize, &memory, &shared_state_handle_, &duped);
  if (!result)
    return false;

  shared_state_ = static_cast<gpu::CommandBufferSharedState*>(memory);

  shared_state()->Initialize();

  mus::mojom::CommandBufferLostContextObserverPtr observer_ptr;
  observer_binding_.Bind(GetProxy(&observer_ptr), async_waiter_);
  mus::mojom::CommandBufferInfoPtr info;
  command_buffer_->Initialize(
      std::move(observer_ptr), std::move(duped),
      mojo::Array<int32_t>::From(attribs_),
      base::Bind(&Copy<mus::mojom::CommandBufferInfoPtr>, &info));

  base::ThreadRestrictions::ScopedAllowWait wait;
  if (!command_buffer_.WaitForIncomingResponse()) {
    VLOG(1) << "Channel encountered error while creating command buffer.";
    return false;
  }

  if (!info) {
    VLOG(1) << "Command buffer cannot be initialized successfully.";
    return false;
  }

  DCHECK_EQ(gpu::CommandBufferNamespace::MOJO, info->command_buffer_namespace);
  command_buffer_id_ = info->command_buffer_id;
  capabilities_ = info->capabilities.To<gpu::Capabilities>();
  return true;
}

gpu::CommandBuffer::State CommandBufferClientImpl::GetLastState() {
  return last_state_;
}

int32_t CommandBufferClientImpl::GetLastToken() {
  TryUpdateState();
  return last_state_.token;
}

void CommandBufferClientImpl::Flush(int32_t put_offset) {
  if (last_put_offset_ == put_offset)
    return;

  last_put_offset_ = put_offset;
  command_buffer_->Flush(put_offset);
  flushed_fence_sync_release_ = next_fence_sync_release_ - 1;
}

void CommandBufferClientImpl::OrderingBarrier(int32_t put_offset) {
  // TODO(jamesr): Implement this more efficiently.
  Flush(put_offset);
}

void CommandBufferClientImpl::WaitForTokenInRange(int32_t start, int32_t end) {
  TryUpdateState();
  while (!InRange(start, end, last_state_.token) &&
         last_state_.error == gpu::error::kNoError) {
    MakeProgressAndUpdateState();
  }
}

void CommandBufferClientImpl::WaitForGetOffsetInRange(int32_t start,
                                                      int32_t end) {
  TryUpdateState();
  while (!InRange(start, end, last_state_.get_offset) &&
         last_state_.error == gpu::error::kNoError) {
    MakeProgressAndUpdateState();
  }
}

void CommandBufferClientImpl::SetGetBuffer(int32_t shm_id) {
  command_buffer_->SetGetBuffer(shm_id);
  last_put_offset_ = -1;
}

scoped_refptr<gpu::Buffer> CommandBufferClientImpl::CreateTransferBuffer(
    size_t size,
    int32_t* id) {
  if (size >= std::numeric_limits<uint32_t>::max())
    return NULL;

  void* memory = NULL;
  mojo::ScopedSharedBufferHandle handle;
  mojo::ScopedSharedBufferHandle duped;
  if (!CreateMapAndDupSharedBuffer(size, &memory, &handle, &duped)) {
    if (last_state_.error == gpu::error::kNoError)
      last_state_.error = gpu::error::kLostContext;
    return NULL;
  }

  *id = ++next_transfer_buffer_id_;

  command_buffer_->RegisterTransferBuffer(*id, std::move(duped),
                                          static_cast<uint32_t>(size));

  scoped_ptr<gpu::BufferBacking> backing(
      new mus::MojoBufferBacking(std::move(handle), memory, size));
  scoped_refptr<gpu::Buffer> buffer(new gpu::Buffer(std::move(backing)));
  return buffer;
}

void CommandBufferClientImpl::DestroyTransferBuffer(int32_t id) {
  command_buffer_->DestroyTransferBuffer(id);
}

gpu::Capabilities CommandBufferClientImpl::GetCapabilities() {
  return capabilities_;
}

int32_t CommandBufferClientImpl::CreateImage(ClientBuffer buffer,
                                             size_t width,
                                             size_t height,
                                             unsigned internalformat) {
  int32_t new_id = ++next_image_id_;

  mojo::SizePtr size = mojo::Size::New();
  size->width = static_cast<int32_t>(width);
  size->height = static_cast<int32_t>(height);

  mus::MojoGpuMemoryBufferImpl* gpu_memory_buffer =
      mus::MojoGpuMemoryBufferImpl::FromClientBuffer(buffer);
  gfx::GpuMemoryBufferHandle handle = gpu_memory_buffer->GetHandle();

  bool requires_sync_point = false;
  if (handle.type != gfx::SHARED_MEMORY_BUFFER) {
    requires_sync_point = true;
    NOTIMPLEMENTED();
    return -1;
  }

  base::SharedMemoryHandle dupd_handle =
      base::SharedMemory::DuplicateHandle(handle.handle);
#if defined(OS_WIN)
  HANDLE platform_handle = dupd_handle.GetHandle();
#else
  int platform_handle = dupd_handle.fd;
#endif

  MojoHandle mojo_handle = MOJO_HANDLE_INVALID;
  MojoResult create_result = MojoCreatePlatformHandleWrapper(
      platform_handle, &mojo_handle);
  if (create_result != MOJO_RESULT_OK) {
    NOTIMPLEMENTED();
    return -1;
  }
  mojo::ScopedHandle scoped_handle;
  scoped_handle.reset(mojo::Handle(mojo_handle));
  command_buffer_->CreateImage(
      new_id, std::move(scoped_handle), handle.type, std::move(size),
      static_cast<int32_t>(gpu_memory_buffer->GetFormat()), internalformat);
  if (requires_sync_point) {
    NOTIMPLEMENTED();
    // TODO(jam): need to support this if we support types other than
    // SHARED_MEMORY_BUFFER.
    //gpu_memory_buffer_manager->SetDestructionSyncPoint(gpu_memory_buffer,
    //                                                   InsertSyncPoint());
  }

  return new_id;
}

void CommandBufferClientImpl::DestroyImage(int32_t id) {
  command_buffer_->DestroyImage(id);
}

int32_t CommandBufferClientImpl::CreateGpuMemoryBufferImage(
    size_t width,
    size_t height,
    unsigned internalformat,
    unsigned usage) {
  scoped_ptr<gfx::GpuMemoryBuffer> buffer(mus::MojoGpuMemoryBufferImpl::Create(
      gfx::Size(static_cast<int>(width), static_cast<int>(height)),
      gpu::ImageFactory::DefaultBufferFormatForImageFormat(internalformat),
      gfx::BufferUsage::SCANOUT));
  if (!buffer)
    return -1;

  return CreateImage(buffer->AsClientBuffer(), width, height, internalformat);
}

void CommandBufferClientImpl::SignalQuery(uint32_t query,
                                          const base::Closure& callback) {
  // TODO(piman)
  NOTIMPLEMENTED();
}

void CommandBufferClientImpl::DidLoseContext(int32_t lost_reason) {
  last_state_.error = gpu::error::kLostContext;
  last_state_.context_lost_reason =
      static_cast<gpu::error::ContextLostReason>(lost_reason);
  delegate_->ContextLost();
}

void CommandBufferClientImpl::TryUpdateState() {
  if (last_state_.error == gpu::error::kNoError)
    shared_state()->Read(&last_state_);
}

void CommandBufferClientImpl::MakeProgressAndUpdateState() {
  mus::mojom::CommandBufferStatePtr state;
  command_buffer_->MakeProgress(
      last_state_.get_offset,
      base::Bind(&Copy<mus::mojom::CommandBufferStatePtr>, &state));

  base::ThreadRestrictions::ScopedAllowWait wait;
  if (!command_buffer_.WaitForIncomingResponse()) {
    VLOG(1) << "Channel encountered error while waiting for command buffer.";
    // TODO(piman): is it ok for this to re-enter?
    DidLoseContext(gpu::error::kUnknown);
    return;
  }

  if (state->generation - last_state_.generation < 0x80000000U)
    last_state_ = state.To<State>();
}

void CommandBufferClientImpl::SetLock(base::Lock* lock) {
}

bool CommandBufferClientImpl::IsGpuChannelLost() {
  // This is only possible for out-of-process command buffers.
  return false;
}

void CommandBufferClientImpl::EnsureWorkVisible() {
  // This is only relevant for out-of-process command buffers.
}

gpu::CommandBufferNamespace CommandBufferClientImpl::GetNamespaceID() const {
  return gpu::CommandBufferNamespace::MOJO;
}

uint64_t CommandBufferClientImpl::GetCommandBufferID() const {
  return command_buffer_id_;
}

int32_t CommandBufferClientImpl::GetExtraCommandBufferData() const {
  return 0;
}

uint64_t CommandBufferClientImpl::GenerateFenceSyncRelease() {
  return next_fence_sync_release_++;
}

bool CommandBufferClientImpl::IsFenceSyncRelease(uint64_t release) {
  return release != 0 && release < next_fence_sync_release_;
}

bool CommandBufferClientImpl::IsFenceSyncFlushed(uint64_t release) {
  return release != 0 && release <= flushed_fence_sync_release_;
}

bool CommandBufferClientImpl::IsFenceSyncFlushReceived(uint64_t release) {
  return IsFenceSyncFlushed(release);
}

void CommandBufferClientImpl::SignalSyncToken(const gpu::SyncToken& sync_token,
                                              const base::Closure& callback) {
  // TODO(dyen)
  NOTIMPLEMENTED();
}

bool CommandBufferClientImpl::CanWaitUnverifiedSyncToken(
    const gpu::SyncToken* sync_token) {
  // Right now, MOJO_LOCAL is only used by trusted code, so it is safe to wait
  // on a sync token in MOJO_LOCAL command buffer.
  if (sync_token->namespace_id() == gpu::CommandBufferNamespace::MOJO_LOCAL)
    return true;

  // It is also safe to wait on the same context.
  if (sync_token->namespace_id() == gpu::CommandBufferNamespace::MOJO &&
      sync_token->command_buffer_id() == GetCommandBufferID())
    return true;

  return false;
}

}  // namespace gles2