// 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>
 *     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/cxx/avl_tree>
#include <l4/cxx/std_ops>
#include <l4/sys/cxx/ipc_epiface>
#include <l4/cxx/string>

#include <l4/sys/capability>
#include <l4/re/namespace>

#include <cstddef>

namespace L4Re { namespace Util {

class Dbg;
class Err;

namespace Names {

/**
 * \brief Name class.
 */
class Name : public cxx::String
{
public:

  Name(const char *name = "") : String(name, __builtin_strlen(name)) {}
  Name(const char *name, unsigned long len) : String(name, len) {}
  Name(cxx::String const &n) : String(n) {}
  char const *name() const { return start(); }
  bool operator < (Name const &r) const;
};


/**
 * \internal
 */
class Obj
{
protected:
  unsigned _f;
  union
  {
    l4_cap_idx_t _cap;
    L4::Epiface *_obj;
  };


public:
  enum Flags
  {
    F_rw        = L4Re::Namespace::Rw,
    F_strong    = L4Re::Namespace::Strong,

    F_trusted   = L4Re::Namespace::Trusted,

    F_rights_mask = F_rw | F_strong | F_trusted,

    F_cap        = 0x100,
    F_local      = 0x200,
    F_replacable = 0x400,
    F_base_mask  = 0xf00,
  };


  unsigned flags() const { return _f; }
  void restrict_flags(unsigned max_rights)
  { _f &= (~F_rights_mask | (max_rights & F_rights_mask)); }

  bool is_rw() const { return (_f & F_rw) == F_rw; }
  bool is_strong() const { return _f & F_strong; }

  bool is_valid() const { return _f & F_cap; }
  bool is_complete() const { return is_valid(); }
  bool is_local() const { return _f & F_local; }
  bool is_replacable() const { return _f & F_replacable; }
  bool is_trusted() const { return _f & F_trusted; }

  L4::Epiface *obj() const { if (is_local()) return _obj; return 0; }
  L4::Cap<void> cap() const
  {
    if (!is_local())
      return L4::Cap<void>(_cap);
    if (!_obj)
      return L4::Cap<void>::Invalid;
    return _obj->obj_cap();
  }


  void set(Obj const &o, unsigned flags)
  {
    *this = o;
    restrict_flags(flags);
  }

  explicit Obj(unsigned flags = 0)
  : _f(flags), _cap(L4_INVALID_CAP)
  {}

  Obj(unsigned f, L4::Cap<void> const &cap)
  : _f((f & ~F_base_mask) | F_cap), _cap(cap.cap())
  {}

  Obj(unsigned f, L4::Epiface *o)
  : _f((f & ~F_base_mask) | F_cap | F_local), _obj(o)
  {}

  void reset(unsigned flags)
  {
    _f = (_f & F_replacable) | (flags & ~(F_cap | F_local));
    _cap = L4_INVALID_CAP;
  }


};


/**
 * \internal
 */
class Entry : public cxx::Avl_tree_node
{
private:
  friend class Name_space;
  Name _n;
  Obj  _o;

  bool _dynamic;

public:
  Entry(Name const &n, Obj const &o, bool dynamic = false)
  : _n(n), _o(o), _dynamic(dynamic) {}

  Name const &name() const { return _n; }
  Obj const *obj() const { return &_o; }
  Obj *obj() { return &_o; }
  void obj(Obj const &o) { _o = o; }

  bool is_placeholder() const
  { return !obj()->is_complete(); }

  bool is_dynamic() const { return _dynamic; }

  void set(Obj const &o);

private:
  void * operator new (size_t s);
  void operator delete(void *b);

};

struct Names_get_key
{
  typedef Name Key_type;
  static Key_type const &key_of(Entry const *e)
  { return e->name(); }
};


/**
 * Abstract server-side implementation of the L4::Namespace interface.
 *
 * \internal
 */
class Name_space
{
  friend class Entry;

private:
  typedef cxx::Avl_tree<Entry, Names_get_key> Tree;
  Tree _tree;

protected:
  L4Re::Util::Dbg const &_dbg;
  L4Re::Util::Err const &_err;

public:

  typedef Tree::Const_iterator Const_iterator;

  Const_iterator begin() const { return _tree.begin(); }
  Const_iterator end() const { return _tree.end(); }

  Name_space(L4Re::Util::Dbg const &dbg, L4Re::Util::Err const &err)
  : _dbg(dbg), _err(err)
  {}

  virtual ~Name_space() {}

  Entry *find(Name const &name) const  { return _tree.find_node(name); }
  Entry *remove(Name const &name) { return _tree.remove(name); }
  Entry *find_iter(Name const &name) const;
  bool insert(Entry *e)  { return _tree.insert(e).second; }

  void dump(bool rec = false, int indent = 0) const;

protected:
  // server support --------------------------------------------
  /**
   * Allocate a new entry for the given name.
   *
   * \param n     Name of the entry, must be copied.
   * \param flags Entry flags, see Obj::Flags.
   *
   * \return A pointer to the newly allocated entry or NULL on error.
   *
   * This method is called when a new entry was received. It must
   * allocate memory, copy `n` out of the receive buffer and wrap
   * everything in an Entry.
   */
  virtual Entry *alloc_dynamic_entry(Name const &n, unsigned flags) = 0;

  /**
   * Free an entry previously allocated with alloc_dynamic_entry().
   *
   * \param e  Entry to free.
   */
  virtual void free_dynamic_entry(Entry *e) = 0;

  /**
   * Return a pointer to the epiface assigned to a given label.
   *
   * \param[in]  data     Label or in the local case the capability slot of
   *                      the receiving capability.
   * \param[in]  is_local If true, a local capability slot was supplied, if
   *                      false the label of a locally bound IPC gate.
   * \param[out] lo       Pointer to epiface responsible for the capability.
   *
   * \return #L4_EOK if a valid interface could be found or an error message
   *         otherwise.
   *
   * This method is called when a new entry is registered and some
   * local ID was received for the capability. In this case, the
   * generic implementation needs to get the epiface in order to get
   * the capability.
   *
   * The callee must make sure that the epiface remains valid until
   * free_epiface is called. In particular, the capability slot must
   * not be reallocated as long as the namespace server holds a
   * reference to the epiface.
   */
  virtual int get_epiface(l4_umword_t data, bool is_local, L4::Epiface **lo) = 0;

  /**
   * Return the receive capability for permanent use.
   *
   * \param[out] cap Capability slot with the received capability. Must
   *                 be permanently available until free_capability() is called.
   *
   * This method is called when a new entry is registered together
   * with a capability mapping. It must decide whether and where to
   * store the capability and return the final capability slot.
   * Typical implementations return the capability slot in the receive
   * window and allocate a new receive window.
   */
  virtual int copy_receive_cap(L4::Cap<void> *cap) = 0;

  /**
   * Free a capability previously acquired with copy_receive_cap().
   *
   * \param[in] cap Capability to free.
   *
   * Counterpart of #copy_receive_cap. Free the capability slot when
   * the entry is deleted or changed.
   */
  virtual void free_capability(L4::Cap<void> cap) = 0;

  /**
   * Free epiface previously acquired with get_epiface().
   *
   * \param[in] epiface Epiface to free.
   *
   * Called when an entry that points to an epiface is deleted
   * allowing implementations that hold resources to free them.
   */
  virtual void free_epiface(L4::Epiface *epiface) = 0;

  int insert_entry(Name const &name, unsigned flags, Entry **e);

public:
  // server interface ------------------------------------------
  int op_query(L4Re::Namespace::Rights,
               L4::Ipc::Array_in_buf<char, unsigned long> const &name,
               L4::Ipc::Snd_fpage &snd_cap, L4::Ipc::Opt<L4::Opcode> &,
               L4::Ipc::Opt<L4::Ipc::Array_ref<char, unsigned long> > &out_name);

  int op_register_obj(L4Re::Namespace::Rights, unsigned flags,
                      L4::Ipc::Array_in_buf<char, unsigned long> const &name,
                      L4::Ipc::Snd_fpage &cap);

  int op_unlink(L4Re::Namespace::Rights r,
                L4::Ipc::Array_in_buf<char, unsigned long> const &name);
};

}}}