// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2011 Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Torsten Frenzel <frenzel@os.inf.tu-dresden.de>
 *               Adam Lackorzysnski <adam@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
#pragma once

#include <l4/sys/types.h>
#include <l4/sys/vcon>
#include <l4/sys/cxx/ipc_legacy>

namespace L4Re { namespace Util {

/**
 * \brief Console server template class.
 * \ingroup api_l4re_util
 *
 * This template uses vcon_write() and vcon_read() to get and deliver data
 * from the implementor.
 *
 * vcon_read() needs to update the status argument with the
 * L4_vcon_read_stat flags, especially the L4_VCON_READ_STAT_DONE flag
 * to indicate that there's nothing more to read for the other end.
 *
 * vcon_write() gets the live data from the UTCB. Make sure to copy out the
 * data before using the UTCB again.
 *
 * The size parameter of both functions is given in bytes.
 */
template< typename SVR >
class Vcon_svr
{
public:
  L4_RPC_LEGACY_DISPATCH(L4::Vcon);

  l4_msgtag_t op_dispatch(l4_utcb_t *utcb, l4_msgtag_t tag, L4::Vcon::Rights)
  {
    l4_msg_regs_t *m = l4_utcb_mr_u(utcb);
    L4::Opcode op = m->mr[0];

    switch (op)
      {
      case L4_VCON_WRITE_OP:
        if (tag.words() < 3)
          return l4_msgtag(-L4_ENOREPLY, 0, 0, 0);

        this_vcon()->vcon_write((char const *)&m->mr[2], m->mr[1]);
        return l4_msgtag(-L4_ENOREPLY, 0, 0, 0);

      case L4_VCON_SET_ATTR_OP:
        if (tag.words() < 4)
          return l4_msgtag(-L4_EINVAL, 0, 0, 0);

        return l4_msgtag(this_vcon()->vcon_set_attr((l4_vcon_attr_t const *)&m->mr[1]),
                         0, 0, 0);

      case L4_VCON_GET_ATTR_OP:
        return l4_msgtag(this_vcon()->vcon_get_attr((l4_vcon_attr_t *)&m->mr[1]),
                         4, 0, 0);

      default:
        break;
      }

    unsigned size = op >> 16;

    if (size > (L4_UTCB_GENERIC_DATA_SIZE - 1) * sizeof(l4_utcb_mr()->mr[0]))
      size = (L4_UTCB_GENERIC_DATA_SIZE - 1) * sizeof(l4_utcb_mr()->mr[0]);

    char buf[size];
    // Hmm, could we avoid the double copy here?
    l4_umword_t v = this_vcon()->vcon_read(buf, size);
    unsigned bytes = v & L4_VCON_READ_SIZE_MASK;

    if (bytes < size)
      v |= L4_VCON_READ_STAT_DONE;

    m->mr[0] = v;
    __builtin_memcpy(&m->mr[1], buf, bytes);

    return l4_msgtag(0,
                     (bytes + sizeof(l4_umword_t) - 1) / sizeof(l4_umword_t) + 1,
                     0, 0);
  }

  unsigned vcon_read(char *buf, unsigned size) noexcept;
  void vcon_write(const char *buf, unsigned size) noexcept;
  int vcon_set_attr(l4_vcon_attr_t const *) noexcept
  { return -L4_EOK; }
  int vcon_get_attr(l4_vcon_attr_t *attr) noexcept
  {
    attr->l_flags = attr->o_flags = attr->i_flags = 0;
    return -L4_EOK;
  }

private:
  SVR const *this_vcon() const { return static_cast<SVR const *>(this); }
  SVR *this_vcon() { return static_cast<SVR *>(this); }
};

}}