// 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 "content/renderer/pepper/ppb_buffer_impl.h"

#include <algorithm>

#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "content/renderer/pepper/common.h"
#include "content/renderer/render_thread_impl.h"
#include "ppapi/c/dev/ppb_buffer_dev.h"
#include "ppapi/c/pp_errors.h"
#include "ppapi/c/pp_instance.h"
#include "ppapi/c/pp_resource.h"

using ppapi::thunk::PPB_Buffer_API;

namespace content {

PPB_Buffer_Impl::PPB_Buffer_Impl(PP_Instance instance)
    : Resource(ppapi::OBJECT_IS_IMPL, instance), size_(0), map_count_(0) {}

PPB_Buffer_Impl::~PPB_Buffer_Impl() {}

// static
PP_Resource PPB_Buffer_Impl::Create(PP_Instance instance, uint32_t size) {
  scoped_refptr<PPB_Buffer_Impl> new_resource(CreateResource(instance, size));
  if (new_resource.get())
    return new_resource->GetReference();
  return 0;
}

// static
scoped_refptr<PPB_Buffer_Impl> PPB_Buffer_Impl::CreateResource(
    PP_Instance instance,
    uint32_t size) {
  scoped_refptr<PPB_Buffer_Impl> buffer(new PPB_Buffer_Impl(instance));
  if (!buffer->Init(size))
    return scoped_refptr<PPB_Buffer_Impl>();
  return buffer;
}

PPB_Buffer_Impl* PPB_Buffer_Impl::AsPPB_Buffer_Impl() { return this; }

PPB_Buffer_API* PPB_Buffer_Impl::AsPPB_Buffer_API() { return this; }

bool PPB_Buffer_Impl::Init(uint32_t size) {
  if (size == 0)
    return false;
  size_ = size;
  shared_memory_.reset(
      RenderThread::Get()->HostAllocateSharedMemoryBuffer(size).release());
  return shared_memory_.get() != NULL;
}

PP_Bool PPB_Buffer_Impl::Describe(uint32_t* size_in_bytes) {
  *size_in_bytes = size_;
  return PP_TRUE;
}

PP_Bool PPB_Buffer_Impl::IsMapped() {
  return PP_FromBool(!!shared_memory_->memory());
}

void* PPB_Buffer_Impl::Map() {
  DCHECK(size_);
  DCHECK(shared_memory_.get());
  if (map_count_++ == 0)
    shared_memory_->Map(size_);
  return shared_memory_->memory();
}

void PPB_Buffer_Impl::Unmap() {
  if (--map_count_ == 0)
    shared_memory_->Unmap();
}

int32_t PPB_Buffer_Impl::GetSharedMemory(int* shm_handle) {
#if defined(OS_POSIX)
  *shm_handle = shared_memory_->handle().fd;
#elif defined(OS_WIN)
  *shm_handle = reinterpret_cast<int>(shared_memory_->handle());
#else
#error "Platform not supported."
#endif
  return PP_OK;
}

BufferAutoMapper::BufferAutoMapper(PPB_Buffer_API* api) : api_(api) {
  needs_unmap_ = !PP_ToBool(api->IsMapped());
  data_ = api->Map();
  api->Describe(&size_);
}

BufferAutoMapper::~BufferAutoMapper() {
  if (needs_unmap_)
    api_->Unmap();
}

}  // namespace content