win_iocp_socket_service.hpp

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//
// win_iocp_socket_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2007 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_HPP
#define ASIO_DETAIL_WIN_IOCP_SOCKET_SERVICE_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/push_options.hpp"

#include "asio/detail/win_iocp_io_service_fwd.hpp"

#if defined(ASIO_HAS_IOCP)

#include "asio/detail/push_options.hpp"
#include <cstring>
#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>
#include "asio/detail/pop_options.hpp"

#include "asio/buffer.hpp"
#include "asio/error.hpp"
#include "asio/io_service.hpp"
#include "asio/socket_base.hpp"
#include "asio/detail/bind_handler.hpp"
#include "asio/detail/handler_alloc_helpers.hpp"
#include "asio/detail/handler_invoke_helpers.hpp"
#include "asio/detail/mutex.hpp"
#include "asio/detail/select_reactor.hpp"
#include "asio/detail/socket_holder.hpp"
#include "asio/detail/socket_ops.hpp"
#include "asio/detail/socket_types.hpp"
#include "asio/detail/win_iocp_io_service.hpp"

namespace asio {
namespace detail {

template <typename Protocol>
class win_iocp_socket_service
  : public asio::detail::service_base<win_iocp_socket_service<Protocol> >
{
public:
  // The protocol type.
  typedef Protocol protocol_type;

  // The endpoint type.
  typedef typename Protocol::endpoint endpoint_type;

  // Base class for all operations.
  typedef win_iocp_operation operation;

  struct noop_deleter { void operator()(void*) {} };
  typedef boost::shared_ptr<void> shared_cancel_token_type;
  typedef boost::weak_ptr<void> weak_cancel_token_type;

  // The native type of a socket.
  class native_type
  {
  public:
    native_type(socket_type s)
      : socket_(s),
        have_remote_endpoint_(false)
    {
    }

    native_type(socket_type s, const endpoint_type& ep)
      : socket_(s),
        have_remote_endpoint_(true),
        remote_endpoint_(ep)
    {
    }

    void operator=(socket_type s)
    {
      socket_ = s;
      have_remote_endpoint_ = false;
      remote_endpoint_ = endpoint_type();
    }

    operator socket_type() const
    {
      return socket_;
    }

    HANDLE as_handle() const
    {
      return reinterpret_cast<HANDLE>(socket_);
    }

    bool have_remote_endpoint() const
    {
      return have_remote_endpoint_;
    }

    endpoint_type remote_endpoint() const
    {
      return remote_endpoint_;
    }

  private:
    socket_type socket_;
    bool have_remote_endpoint_;
    endpoint_type remote_endpoint_;
  };

  // The implementation type of the socket.
  class implementation_type
  {
  public:
    // Default constructor.
    implementation_type()
      : socket_(invalid_socket),
        flags_(0),
        cancel_token_(),
        protocol_(endpoint_type().protocol()),
        next_(0),
        prev_(0)
    {
    }

  private:
    // Only this service will have access to the internal values.
    friend class win_iocp_socket_service;

    // The native socket representation.
    native_type socket_;

    enum
    {
      enable_connection_aborted = 1, // User wants connection_aborted errors.
      close_might_block = 2, // User set linger option for blocking close.
      user_set_non_blocking = 4 // The user wants a non-blocking socket.
    };

    // Flags indicating the current state of the socket.
    unsigned char flags_;

    // We use a shared pointer as a cancellation token here to work around the
    // broken Windows support for cancellation. MSDN says that when you call
    // closesocket any outstanding WSARecv or WSASend operations will complete
    // with the error ERROR_OPERATION_ABORTED. In practice they complete with
    // ERROR_NETNAME_DELETED, which means you can't tell the difference between
    // a local cancellation and the socket being hard-closed by the peer.
    shared_cancel_token_type cancel_token_;

    // The protocol associated with the socket.
    protocol_type protocol_;

    // The ID of the thread from which it is safe to cancel asynchronous
    // operations. 0 means no asynchronous operations have been started yet.
    // ~0 means asynchronous operations have been started from more than one
    // thread, and cancellation is not supported for the socket.
    DWORD safe_cancellation_thread_id_;

    // Pointers to adjacent socket implementations in linked list.
    implementation_type* next_;
    implementation_type* prev_;
  };

  // The type of the reactor used for connect operations.
  typedef detail::select_reactor<true> reactor_type;

  // The maximum number of buffers to support in a single operation.
  enum { max_buffers = 64 < max_iov_len ? 64 : max_iov_len };

  // Constructor.
  win_iocp_socket_service(asio::io_service& io_service)
    : asio::detail::service_base<
        win_iocp_socket_service<Protocol> >(io_service),
      iocp_service_(asio::use_service<win_iocp_io_service>(io_service)),
      reactor_(0),
      mutex_(),
      impl_list_(0)
  {
  }

  // Destroy all user-defined handler objects owned by the service.
  void shutdown_service()
  {
    // Close all implementations, causing all operations to complete.
    asio::detail::mutex::scoped_lock lock(mutex_);
    implementation_type* impl = impl_list_;
    while (impl)
    {
      asio::error_code ignored_ec;
      close_for_destruction(*impl);
      impl = impl->next_;
    }
  }

  // Construct a new socket implementation.
  void construct(implementation_type& impl)
  {
    impl.socket_ = invalid_socket;
    impl.flags_ = 0;
    impl.cancel_token_.reset();
    impl.safe_cancellation_thread_id_ = 0;

    // Insert implementation into linked list of all implementations.
    asio::detail::mutex::scoped_lock lock(mutex_);
    impl.next_ = impl_list_;
    impl.prev_ = 0;
    if (impl_list_)
      impl_list_->prev_ = &impl;
    impl_list_ = &impl;
  }

  // Destroy a socket implementation.
  void destroy(implementation_type& impl)
  {
    close_for_destruction(impl);

    // Remove implementation from linked list of all implementations.
    asio::detail::mutex::scoped_lock lock(mutex_);
    if (impl_list_ == &impl)
      impl_list_ = impl.next_;
    if (impl.prev_)
      impl.prev_->next_ = impl.next_;
    if (impl.next_)
      impl.next_->prev_= impl.prev_;
    impl.next_ = 0;
    impl.prev_ = 0;
  }

  // Open a new socket implementation.
  asio::error_code open(implementation_type& impl,
      const protocol_type& protocol, asio::error_code& ec)
  {
    if (is_open(impl))
    {
      ec = asio::error::already_open;
      return ec;
    }

    socket_holder sock(socket_ops::socket(protocol.family(), protocol.type(),
          protocol.protocol(), ec));
    if (sock.get() == invalid_socket)
      return ec;

    HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock.get());
    iocp_service_.register_handle(sock_as_handle);

    impl.socket_ = sock.release();
    impl.flags_ = 0;
    impl.cancel_token_.reset(static_cast<void*>(0), noop_deleter());
    impl.protocol_ = protocol;
    ec = asio::error_code();
    return ec;
  }

  // Assign a native socket to a socket implementation.
  asio::error_code assign(implementation_type& impl,
      const protocol_type& protocol, const native_type& native_socket,
      asio::error_code& ec)
  {
    if (is_open(impl))
    {
      ec = asio::error::already_open;
      return ec;
    }

    iocp_service_.register_handle(native_socket.as_handle());

    impl.socket_ = native_socket;
    impl.flags_ = 0;
    impl.cancel_token_.reset(static_cast<void*>(0), noop_deleter());
    impl.protocol_ = protocol;
    ec = asio::error_code();
    return ec;
  }

  // Determine whether the socket is open.
  bool is_open(const implementation_type& impl) const
  {
    return impl.socket_ != invalid_socket;
  }

  // Destroy a socket implementation.
  asio::error_code close(implementation_type& impl,
      asio::error_code& ec)
  {
    if (is_open(impl))
    {
      // Check if the reactor was created, in which case we need to close the
      // socket on the reactor as well to cancel any operations that might be
      // running there.
      reactor_type* reactor = static_cast<reactor_type*>(
            interlocked_compare_exchange_pointer(
              reinterpret_cast<void**>(&reactor_), 0, 0));
      if (reactor)
        reactor->close_descriptor(impl.socket_);

      if (socket_ops::close(impl.socket_, ec) == socket_error_retval)
        return ec;

      impl.socket_ = invalid_socket;
      impl.flags_ = 0;
      impl.cancel_token_.reset();
      impl.safe_cancellation_thread_id_ = 0;
    }

    ec = asio::error_code();
    return ec;
  }

  // Get the native socket representation.
  native_type native(implementation_type& impl)
  {
    return impl.socket_;
  }

  // Cancel all operations associated with the socket.
  asio::error_code cancel(implementation_type& impl,
      asio::error_code& ec)
  {
    if (!is_open(impl))
    {
      ec = asio::error::bad_descriptor;
    }
    else if (FARPROC cancel_io_ex_ptr = ::GetProcAddress(
          ::GetModuleHandleA("KERNEL32"), "CancelIoEx"))
    {
      // The version of Windows supports cancellation from any thread.
      typedef BOOL (WINAPI* cancel_io_ex_t)(HANDLE, LPOVERLAPPED);
      cancel_io_ex_t cancel_io_ex = (cancel_io_ex_t)cancel_io_ex_ptr;
      socket_type sock = impl.socket_;
      HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock);
      if (!cancel_io_ex(sock_as_handle, 0))
      {
        DWORD last_error = ::GetLastError();
        ec = asio::error_code(last_error,
            asio::error::get_system_category());
      }
      else
      {
        ec = asio::error_code();
      }
    }
    else if (impl.safe_cancellation_thread_id_ == 0)
    {
      // No operations have been started, so there's nothing to cancel.
      ec = asio::error_code();
    }
    else if (impl.safe_cancellation_thread_id_ == ::GetCurrentThreadId())
    {
      // Asynchronous operations have been started from the current thread only,
      // so it is safe to try to cancel them using CancelIo.
      socket_type sock = impl.socket_;
      HANDLE sock_as_handle = reinterpret_cast<HANDLE>(sock);
      if (!::CancelIo(sock_as_handle))
      {
        DWORD last_error = ::GetLastError();
        ec = asio::error_code(last_error,
            asio::error::get_system_category());
      }
      else
      {
        ec = asio::error_code();
      }
    }
    else
    {
      // Asynchronous operations have been started from more than one thread,
      // so cancellation is not safe.
      ec = asio::error::operation_not_supported;
    }

    return ec;
  }

  // Determine whether the socket is at the out-of-band data mark.
  bool at_mark(const implementation_type& impl,
      asio::error_code& ec) const
  {
    if (!is_open(impl))
    {
      ec = asio::error::bad_descriptor;
      return false;
    }

    asio::detail::ioctl_arg_type value = 0;
    socket_ops::ioctl(impl.socket_, SIOCATMARK, &value, ec);
    return ec ? false : value != 0;
  }

  // Determine the number of bytes available for reading.
  std::size_t available(const implementation_type& impl,
      asio::error_code& ec) const
  {
    if (!is_open(impl))
    {
      ec = asio::error::bad_descriptor;
      return 0;
    }

    asio::detail::ioctl_arg_type value = 0;
    socket_ops::ioctl(impl.socket_, FIONREAD, &value, ec);
    return ec ? static_cast<std::size_t>(0) : static_cast<std::size_t>(value);
  }