// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
 *               Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Torsten Frenzel <frenzel@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 <cstring>
#include <cstddef>
#include <l4/sys/types.h>
#include <l4/cxx/list>
#include <l4/cxx/minmax>
#include <l4/re/dataspace>
#include <l4/re/dataspace-sys.h>
#include <l4/sys/cxx/ipc_legacy>

namespace L4Re { namespace Util {

/**
 * Dataspace server class.
 *
 * The default implementation of the interface provides a continuous dataspace
 * with contiguous pages.
 */
class Dataspace_svr
{
private:
  typedef L4::Ipc::Gen_fpage<L4::Ipc::Snd_item> Snd_fpage;
public:
  L4_RPC_LEGACY_DISPATCH(L4Re::Dataspace);

  typedef Snd_fpage::Map_type Map_type;
  typedef Snd_fpage::Cacheopt Cache_type;

  Dataspace_svr() noexcept
  : _ds_start(0), _ds_size(0), _map_flags(Snd_fpage::Map),
    _cache_flags(Snd_fpage::Cached)
  {}

  virtual ~Dataspace_svr() noexcept {}

  /**
   * Map a region of the dataspace
   *
   * \param      offset      Offset to start within data space
   * \param      local_addr  Local address to map to.
   * \param      flags       Dataspace flags, see #L4Re::Dataspace::F::Flags.
   * \param      min_addr    Defines start of receive window.
   * \param      max_addr    Defines end of receive window.
   * \param[out] memory      Send fpage to map
   *
   * \retval 0   Success
   * \retval <0  Error
   */
  int map(Dataspace::Offset offset,
          Dataspace::Map_addr local_addr,
          Dataspace::Flags flags,
          Dataspace::Map_addr min_addr,
          Dataspace::Map_addr max_addr,
          L4::Ipc::Snd_fpage &memory);

  /**
   * A hook that is called as the first operation in each map
   *        request.
   * \param offs  Offs param to map
   * \param flags Flags param to map
   * \param min   Min param to map
   * \param max   Max param to map
   * \retval <0   Error and the map request will be aborted with that error.
   * \retval >=0  Success
   *
   * \see map
   */
  virtual int map_hook(Dataspace::Offset offs,
                       Dataspace::Flags flags,
                       Dataspace::Map_addr min,
                       Dataspace::Map_addr max)
  {
    (void)offs; (void)flags; (void)min; (void)max;
    return 0;
  }

  /**
   * Take a reference to this dataspace
   *
   * Default does nothing.
   */
  virtual void take() noexcept
  {}

  /**
   * Release a reference to this dataspace
   *
   * \return Number of references to the dataspace
   *
   * Default does nothing and returns always zero.
   */
  virtual unsigned long release() noexcept
  { return 0; }

  /**
   * Copy from src dataspace to this destination dataspace
   *
   * \param dst_offs  Offset into the destination dataspace
   * \param src_id    Local id of the source dataspace
   * \param src_offs  Offset into the source dataspace
   * \param size      Number of bytes to copy
   *
   * \retval >=0  Number of bytes copied
   * \retval <0   An error occured. The error code may depend on the
   *              implementation.
   */
  virtual long copy(l4_addr_t dst_offs, l4_umword_t src_id,
                    l4_addr_t src_offs, unsigned long size) noexcept
  {
    (void)dst_offs; (void)src_id; (void)src_offs; (void)size;
    return -L4_ENODEV;
  }

  /**
   * Clear a region in the dataspace
   *
   * \param offs Start of the region
   * \param size Size of the region
   *
   * \retval 0   Success
   * \retval <0  Error
   */
  virtual long clear(unsigned long offs, unsigned long size) const noexcept;

  /**
   * Allocate a region within a dataspace
   *
   * \param offset  Offset in the dataspace, in bytes.
   * \param size    Size of the range, in bytes.
   * \param access  Access mode with which the memory backing the dataspace
   *                region should be allocated.
   *
   * \retval 0   Success
   * \retval <0  Error
   */
  virtual long allocate(l4_addr_t offset, l4_size_t size, unsigned access) noexcept
  { (void)offset; (void)size; (void)access; return -L4_ENODEV; }

  /**
   * Define the size of the flexpage to map
   *
   * \return flexpage size
   */
  virtual unsigned long page_shift() const noexcept
  { return L4_LOG2_PAGESIZE; }

  /**
   * Return whether the dataspace is static
   *
   * \return True if dataspace is static
   */
  virtual bool is_static() const noexcept
  { return true; }


  long op_map(L4Re::Dataspace::Rights rights,
              L4Re::Dataspace::Offset offset,
              L4Re::Dataspace::Map_addr spot,
              L4Re::Dataspace::Flags flags,
              L4::Ipc::Snd_fpage &fp)
  {
    auto rf = map_flags(rights);

    if (!rf.w() && flags.w())
      return -L4_EPERM;

    return map(offset, spot, flags & rf, 0, ~0, fp);
  }

  long op_allocate(L4Re::Dataspace::Rights rights,
                   L4Re::Dataspace::Offset offset,
                   L4Re::Dataspace::Size size)
  { return allocate(offset, size, rights & 3); }

  long op_copy_in(L4Re::Dataspace::Rights rights,
                  L4Re::Dataspace::Offset dst_offs,
                  L4::Ipc::Snd_fpage const &src_cap,
                  L4Re::Dataspace::Offset src_offs,
                  L4Re::Dataspace::Size sz)
  {
    if (!src_cap.id_received())
      return -L4_EINVAL;

    if (!(rights & L4_CAP_FPAGE_W))
      return -L4_EACCESS;

    if (sz == 0)
      return L4_EOK;

    return copy(dst_offs, src_cap.data(), src_offs, sz);
  }

  long op_info(L4Re::Dataspace::Rights rights, L4Re::Dataspace::Stats &s)
  {
    s.size = size();
    // only return writable if really writable
    s.flags = Dataspace::Flags(0);
    if (map_flags(rights).w())
      s.flags |= Dataspace::F::W;
    return L4_EOK;
  }

  long op_clear(L4Re::Dataspace::Rights rights,
                L4Re::Dataspace::Offset offset,
                L4Re::Dataspace::Size size)
  {
    if (!map_flags(rights).w())
      return -L4_EACCESS;

    return clear(offset, size);
  }


protected:
  unsigned long size() const noexcept
  { return _ds_size; }
  unsigned long map_flags() const noexcept
  { return _map_flags; }
  unsigned long page_size() const noexcept
  { return 1UL << page_shift(); }
  unsigned long round_size() const noexcept
  { return l4_round_size(size(), page_shift()); }
  bool check_limit(l4_addr_t offset) const noexcept
  { return offset < round_size(); }

  L4Re::Dataspace::Flags
  map_flags(L4Re::Dataspace::Rights rights = L4_CAP_FPAGE_W) const noexcept
  {
    auto f = (_rw_flags & L4Re::Dataspace::Flags(0x0f)) | L4Re::Dataspace::F::Caching_mask;
    if (!(rights & L4_CAP_FPAGE_W))
      f &= ~L4Re::Dataspace::F::W;

    return f;
  }

protected:
  void size(unsigned long size) noexcept { _ds_size = size; }

  l4_addr_t _ds_start;
  l4_size_t _ds_size;
  Map_type _map_flags;
  Cache_type _cache_flags;
  L4Re::Dataspace::Flags _rw_flags;
};

}}