text: /*
   * Copyright (C) 2012 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   * THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "config.h"
  #include "ShareableResource.h"
  
  #if ENABLE(SHAREABLE_RESOURCE)
  
  #include "ArgumentCoders.h"
  #include <WebCore/SharedBuffer.h>
  
  namespace WebKit {
  using namespace WebCore;
  
  ShareableResource::Handle::Handle()
  {
  }
  
  void ShareableResource::Handle::encode(IPC::Encoder& encoder) const
  {
      encoder << m_handle;
      encoder << m_offset;
      encoder << m_size;
  }
  
  bool ShareableResource::Handle::decode(IPC::Decoder& decoder, Handle& handle)
  {
      if (!decoder.decode(handle.m_handle))
          return false;
      if (!decoder.decode(handle.m_offset))
          return false;
      if (!decoder.decode(handle.m_size))
          return false;
      return true;
  }
  
  #if USE(CF)
  static void shareableResourceDeallocate(void *ptr, void *info)
  {
      static_cast<ShareableResource*>(info)->deref(); // Balanced by ref() in createShareableResourceDeallocator()
  }
      
  static CFAllocatorRef createShareableResourceDeallocator(ShareableResource* resource)
  {
      CFAllocatorContext context = { 0,
          resource,
          NULL, // retain
          NULL, // release
          NULL, // copyDescription
          NULL, // allocate
          NULL, // reallocate
          shareableResourceDeallocate,
          NULL, // preferredSize
      };
  
      return CFAllocatorCreate(kCFAllocatorDefault, &context);
  }
  #endif
  
  RefPtr<SharedBuffer> ShareableResource::wrapInSharedBuffer()
  {
      ref(); // Balanced by deref when SharedBuffer is deallocated.
  
  #if USE(CF)
      RetainPtr<CFAllocatorRef> deallocator = adoptCF(createShareableResourceDeallocator(this));
      RetainPtr<CFDataRef> cfData = adoptCF(CFDataCreateWithBytesNoCopy(kCFAllocatorDefault, reinterpret_cast<const UInt8*>(data()), static_cast<CFIndex>(size()), deallocator.get()));
      return SharedBuffer::create(cfData.get());
  #elif USE(SOUP)
      return SharedBuffer::wrapSoupBuffer(soup_buffer_new_with_owner(data(), size(), this, [](void* data) { static_cast<ShareableResource*>(data)->deref(); }));
  #else
      ASSERT_NOT_REACHED();
      return nullptr;
  #endif
  }
  
  RefPtr<SharedBuffer> ShareableResource::Handle::tryWrapInSharedBuffer() const
  {
      RefPtr<ShareableResource> resource = ShareableResource::map(*this);
      if (!resource) {
          LOG_ERROR("Failed to recreate ShareableResource from handle.");
          return nullptr;
      }
  
      return resource->wrapInSharedBuffer();
  }
  
  RefPtr<ShareableResource> ShareableResource::create(Ref<SharedMemory>&& sharedMemory, unsigned offset, unsigned size)
  {
      auto totalSize = CheckedSize(offset) + size;
      if (totalSize.hasOverflowed()) {
          LOG_ERROR("Failed to create ShareableResource from SharedMemory due to overflow.");
          return nullptr;
      }
      if (totalSize.unsafeGet() > sharedMemory->size()) {
          LOG_ERROR("Failed to create ShareableResource from SharedMemory due to mismatched buffer size.");
          return nullptr;
      }
      return adoptRef(*new ShareableResource(WTFMove(sharedMemory), offset, size));
  }
  
  RefPtr<ShareableResource> ShareableResource::map(const Handle& handle)
  {
      auto sharedMemory = SharedMemory::map(handle.m_handle, SharedMemory::Protection::ReadOnly);
      if (!sharedMemory)
          return nullptr;
  
      return create(sharedMemory.releaseNonNull(), handle.m_offset, handle.m_size);
  }
  
  ShareableResource::ShareableResource(Ref<SharedMemory>&& sharedMemory, unsigned offset, unsigned size)
      : m_sharedMemory(WTFMove(sharedMemory))
      , m_offset(offset)
      , m_size(size)
  {
  }
  
  ShareableResource::~ShareableResource()
  {
  }
  
  bool ShareableResource::createHandle(Handle& handle)
  {
      if (!m_sharedMemory->createHandle(handle.m_handle, SharedMemory::Protection::ReadOnly))
          return false;
  
      handle.m_offset = m_offset;
      handle.m_size = m_size;
  
      return true;
  }
  
  const char* ShareableResource::data() const
  {
      return static_cast<const char*>(m_sharedMemory->data()) + m_offset;
  }
  
  unsigned ShareableResource::size() const
  {
      return m_size;
  }
      
  } // namespace WebKit
  
  #endif // ENABLE(SHAREABLE_RESOURCE)
  