// Copyright (c) 2011 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 "webkit/plugins/ppapi/ppb_context_3d_impl.h"

#include "base/logging.h"
#include "base/shared_memory.h"
#include "gpu/command_buffer/client/gles2_cmd_helper.h"
#include "gpu/command_buffer/client/gles2_implementation.h"
#include "gpu/command_buffer/common/command_buffer.h"
#include "ppapi/c/dev/ppb_context_3d_trusted_dev.h"
#include "webkit/plugins/ppapi/common.h"
#include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
#include "webkit/plugins/ppapi/ppb_surface_3d_impl.h"

namespace webkit {
namespace ppapi {

namespace {

// Size of the transfer buffer.
const int32 kCommandBufferSize = 1024 * 1024;
const int32 kTransferBufferSize = 1024 * 1024;

bool ShmToHandle(base::SharedMemory* shm,
                 size_t size,
                 int* shm_handle,
                 uint32_t* shm_size) {
  if (!shm || !shm_handle || !shm_size)
    return false;
#if defined(OS_POSIX)
    *shm_handle = shm->handle().fd;
#elif defined(OS_WIN)
    *shm_handle = reinterpret_cast<int>(shm->handle());
#else
    #error "Platform not supported."
#endif
    *shm_size = size;
    return true;
}

PP_Context3DTrustedState PPStateFromGPUState(gpu::CommandBuffer::State s) {
  PP_Context3DTrustedState state = {
      s.num_entries,
      s.get_offset,
      s.put_offset,
      s.token,
      static_cast<PPB_Context3DTrustedError>(s.error)
  };
  return state;
}

PP_Resource Create(PP_Instance instance_id,
                   PP_Config3D_Dev config,
                   PP_Resource share_context,
                   const int32_t* attrib_list) {
  // TODO(alokp): Support shared context.
  DCHECK_EQ(0, share_context);
  if (share_context != 0)
    return 0;

  PluginInstance* instance = ResourceTracker::Get()->GetInstance(instance_id);
  if (!instance)
    return 0;

  scoped_refptr<PPB_Context3D_Impl> context(
      new PPB_Context3D_Impl(instance));
  if (!context->Init(config, share_context, attrib_list))
    return 0;

  return context->GetReference();
}

PP_Bool IsContext3D(PP_Resource resource) {
  return BoolToPPBool(!!Resource::GetAs<PPB_Context3D_Impl>(resource));
}

int32_t GetAttrib(PP_Resource context,
                  int32_t attribute,
                  int32_t* value) {
  // TODO(alokp): Implement me.
  return 0;
}

int32_t BindSurfaces(PP_Resource context_id,
                     PP_Resource draw,
                     PP_Resource read) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get())
    return PP_ERROR_BADRESOURCE;

  scoped_refptr<PPB_Surface3D_Impl> draw_surface(
      Resource::GetAs<PPB_Surface3D_Impl>(draw));
  if (!draw_surface.get())
    return PP_ERROR_BADRESOURCE;

  scoped_refptr<PPB_Surface3D_Impl> read_surface(
      Resource::GetAs<PPB_Surface3D_Impl>(read));
  if (!read_surface.get())
    return PP_ERROR_BADRESOURCE;

  return context->BindSurfaces(draw_surface.get(), read_surface.get());
}

int32_t GetBoundSurfaces(PP_Resource context,
                         PP_Resource* draw,
                         PP_Resource* read) {
  // TODO(alokp): Implement me.
  return 0;
}

const PPB_Context3D_Dev ppb_context3d = {
  &Create,
  &IsContext3D,
  &GetAttrib,
  &BindSurfaces,
  &GetBoundSurfaces,
};

PP_Resource CreateRaw(PP_Instance instance_id,
                      PP_Config3D_Dev config,
                      PP_Resource share_context,
                      const int32_t* attrib_list) {
  // TODO(alokp): Support shared context.
  DCHECK_EQ(0, share_context);
  if (share_context != 0)
    return 0;

  PluginInstance* instance = ResourceTracker::Get()->GetInstance(instance_id);
  if (!instance)
    return 0;

  scoped_refptr<PPB_Context3D_Impl> context(
      new PPB_Context3D_Impl(instance));
  if (!context->InitRaw(config, share_context, attrib_list))
    return 0;

  return context->GetReference();
}

PP_Bool Initialize(PP_Resource context_id, int32_t size) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return PP_FALSE;
  return context->command_buffer()->Initialize(size) ? PP_TRUE : PP_FALSE;
}

PP_Bool GetRingBuffer(PP_Resource context_id,
                      int* shm_handle,
                      uint32_t* shm_size) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return PP_FALSE;

  gpu::Buffer buffer = context->command_buffer()->GetRingBuffer();

  return ShmToHandle(buffer.shared_memory, buffer.size, shm_handle, shm_size)
    ? PP_TRUE : PP_FALSE;
}

PP_Context3DTrustedState GetState(PP_Resource context_id) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer()) {
    PP_Context3DTrustedState error_state = { 0 };
    return error_state;
  }

  return PPStateFromGPUState(context->command_buffer()->GetState());
}

PP_Bool Flush(PP_Resource context_id, int32_t put_offset) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return PP_FALSE;

  context->command_buffer()->Flush(put_offset);
  return PP_TRUE;
}

PP_Context3DTrustedState FlushSync(PP_Resource context_id, int32_t put_offset) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer()) {
    PP_Context3DTrustedState error_state = { 0 };
    return error_state;
  }

  return PPStateFromGPUState(context->command_buffer()->FlushSync(put_offset));
}

int32_t CreateTransferBuffer(PP_Resource context_id, uint32_t size) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return 0;
  return context->command_buffer()->CreateTransferBuffer(size, -1);
}

PP_Bool DestroyTransferBuffer(PP_Resource context_id, int32_t id) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return PP_FALSE;
  context->command_buffer()->DestroyTransferBuffer(id);
  return PP_TRUE;
}

PP_Bool GetTransferBuffer(PP_Resource context_id,
                          int32_t id,
                          int* shm_handle,
                          uint32_t* shm_size) {
  scoped_refptr<PPB_Context3D_Impl> context(
      Resource::GetAs<PPB_Context3D_Impl>(context_id));
  if (!context.get() || !context->command_buffer())
    return PP_FALSE;
  gpu::Buffer buffer = context->command_buffer()->GetTransferBuffer(id);

  return ShmToHandle(buffer.shared_memory, buffer.size, shm_handle, shm_size)
      ? PP_TRUE : PP_FALSE;
}

}  // namespace

PPB_Context3D_Impl::PPB_Context3D_Impl(PluginInstance* instance)
    : Resource(instance),
      instance_(instance),
      transfer_buffer_id_(0),
      draw_surface_(NULL),
      read_surface_(NULL),
      callback_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
}

PPB_Context3D_Impl::~PPB_Context3D_Impl() {
  Destroy();
}

const PPB_Context3D_Dev* PPB_Context3D_Impl::GetInterface() {
  return &ppb_context3d;
}

const PPB_Context3DTrusted_Dev* PPB_Context3D_Impl::GetTrustedInterface() {
  static const PPB_Context3DTrusted_Dev iface = {
    &CreateRaw,
    &Initialize,
    &GetRingBuffer,
    &GetState,
    &Flush,
    &FlushSync,
    &CreateTransferBuffer,
    &DestroyTransferBuffer,
    &GetTransferBuffer
  };
  return &iface;
}

PPB_Context3D_Impl* PPB_Context3D_Impl::AsPPB_Context3D_Impl() {
  return this;
}

bool PPB_Context3D_Impl::InitRaw(PP_Config3D_Dev config,
                                 PP_Resource share_context,
                                 const int32_t* attrib_list) {
  // Create and initialize the objects required to issue GLES2 calls.
  platform_context_.reset(instance()->CreateContext3D());
  if (!platform_context_.get()) {
    Destroy();
    return false;
  }
  if (!platform_context_->Init()) {
    Destroy();
    return false;
  }
  platform_context_->SetContextLostCallback(
      callback_factory_.NewCallback(&PPB_Context3D_Impl::OnContextLost));
  return true;
}

bool PPB_Context3D_Impl::Init(PP_Config3D_Dev config,
                              PP_Resource share_context,
                              const int32_t* attrib_list) {
  if (!InitRaw(config, share_context, attrib_list))
    return false;

  if (!CreateImplementation()) {
    Destroy();
    return false;
  }

  return true;
}

bool PPB_Context3D_Impl::CreateImplementation() {
  gpu::CommandBuffer* command_buffer = platform_context_->GetCommandBuffer();
  DCHECK(command_buffer);

  if (!command_buffer->Initialize(kCommandBufferSize))
    return false;

  // Create the GLES2 helper, which writes the command buffer protocol.
  helper_.reset(new gpu::gles2::GLES2CmdHelper(command_buffer));
  if (!helper_->Initialize(kCommandBufferSize))
    return false;

  // Create a transfer buffer used to copy resources between the renderer
  // process and the GPU process.
  transfer_buffer_id_ =
      command_buffer->CreateTransferBuffer(kTransferBufferSize, -1);
  if (transfer_buffer_id_ < 0)
    return false;

  // Map the buffer into the renderer process's address space.
  gpu::Buffer transfer_buffer =
      command_buffer->GetTransferBuffer(transfer_buffer_id_);
  if (!transfer_buffer.ptr)
    return false;

  // Create the object exposing the OpenGL API.
  gles2_impl_.reset(new gpu::gles2::GLES2Implementation(
      helper_.get(),
      transfer_buffer.size,
      transfer_buffer.ptr,
      transfer_buffer_id_,
      false));

  return true;
}

int32_t PPB_Context3D_Impl::BindSurfaces(PPB_Surface3D_Impl* draw,
                                         PPB_Surface3D_Impl* read) {
  // TODO(alokp): Support separate draw-read surfaces.
  DCHECK_EQ(draw, read);
  if (draw != read)
    return PP_GRAPHICS3DERROR_BAD_MATCH;

  if (draw == draw_surface_)
    return PP_OK;

  if (draw && draw->context())
    return PP_GRAPHICS3DERROR_BAD_ACCESS;

  if (draw_surface_)
    draw_surface_->BindToContext(NULL);
  if (draw && !draw->BindToContext(this))
    return PP_ERROR_NOMEMORY;

  draw_surface_ = draw;
  read_surface_ = read;
  return PP_OK;
}

void PPB_Context3D_Impl::Destroy() {
  if (draw_surface_)
    draw_surface_->BindToContext(NULL);

  gles2_impl_.reset();

  if (command_buffer() && transfer_buffer_id_ != 0) {
    command_buffer()->DestroyTransferBuffer(transfer_buffer_id_);
    transfer_buffer_id_ = 0;
  }

  helper_.reset();
  platform_context_.reset();
}

void PPB_Context3D_Impl::OnContextLost() {
  if (draw_surface_)
    draw_surface_->OnContextLost();
  if (read_surface_)
    read_surface_->OnContextLost();
}

gpu::CommandBuffer *PPB_Context3D_Impl::command_buffer() {
  return platform_context_.get() ? platform_context_->GetCommandBuffer() : NULL;
}

}  // namespace ppapi
}  // namespace webkit