action-container.h

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/*

Copyright (C) 1993-2018 John W. Eaton
Copyright (C) 2009-2010 VZLU Prague

This file is part of Octave.

Octave is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Octave is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<https://www.gnu.org/licenses/>.

*/

#if ! defined (octave_action_container_h)
#define octave_action_container_h 1

#include "octave-config.h"

#include <cstddef>

// This class allows registering actions in a list for later
// execution, either explicitly or when the container goes out of
// scope.

// FIXME: is there a better name for this class?

// FIXME: we should probably be using std::function, std::bind, and
// related c++11 features to implement this functionality.

namespace octave
{
  class
  action_container
  {
  public:

    // A generic unwind_protect element.  Knows how to run itself and
    // discard itself.  Also, contains a pointer to the next element.
    class elem
    {
    public:

      friend class action_container;

      elem (void) { }

      // No copying!

      elem (const elem&) = delete;

      elem& operator = (const elem&) = delete;

      virtual ~elem (void) = default;

      virtual void run (void) { }
    };

    // An element that merely runs a void (*)(void) function.

    class fcn_elem : public elem
    {
    public:

      fcn_elem (void (*fptr) (void))
        : e_fptr (fptr) { }

      void run (void) { e_fptr (); }

    private:

      void (*e_fptr) (void);
    };

    // An element that stores a variable of type T along with a void (*) (T)
    // function pointer, and calls the function with the parameter.

    template <typename T>
    class fcn_arg_elem : public elem
    {
    public:

      fcn_arg_elem (void (*fcn) (T), T arg)
        : e_fcn (fcn), e_arg (arg) { }

      // No copying!

      fcn_arg_elem (const fcn_arg_elem&) = delete;

      fcn_arg_elem& operator = (const fcn_arg_elem&) = delete;

      void run (void) { e_fcn (e_arg); }

    private:

      void (*e_fcn) (T);

      T e_arg;
    };

    // An element that stores a variable of type T along with a
    // void (*) (const T&) function pointer, and calls the function with
    // the parameter.

    template <typename T>
    class fcn_crefarg_elem : public elem
    {
    public:

      fcn_crefarg_elem (void (*fcn) (const T&), const T& arg)
        : e_fcn (fcn), e_arg (arg) { }

      void run (void) { e_fcn (e_arg); }

    private:

      void (*e_fcn) (const T&);

      T e_arg;
    };

    // An element for calling a member function.

    template <typename T>
    class method_elem : public elem
    {
    public:

      method_elem (T *obj, void (T::*method) (void))
        : e_obj (obj), e_method (method) { }

      method_elem (T& obj, void (T::*method) (void))
        : e_obj (&obj), e_method (method) { }

      // No copying!

      method_elem (const method_elem&) = delete;

      method_elem operator = (const method_elem&) = delete;

      void run (void) { (e_obj->*e_method) (); }

    private:

      T *e_obj;

      void (T::*e_method) (void);
    };

    // An element for calling a member function with a single argument

    template <typename T, typename A>
    class method_arg_elem : public elem
    {
    public:

      method_arg_elem (T *obj, void (T::*method) (A), A arg)
        : e_obj (obj), e_method (method), e_arg (arg) { }

      method_arg_elem (T& obj, void (T::*method) (A), A arg)
        : e_obj (&obj), e_method (method), e_arg (arg) { }

      // No copying!

      method_arg_elem (const method_arg_elem&) = delete;

      method_arg_elem operator = (const method_arg_elem&) = delete;

      void run (void) { (e_obj->*e_method) (e_arg); }

    private:

      T *e_obj;

      void (T::*e_method) (A);

      A e_arg;
    };

    // An element for calling a member function with a single argument

    template <typename T, typename A>
    class method_crefarg_elem : public elem
    {
    public:

      method_crefarg_elem (T *obj, void (T::*method) (const A&), const A& arg)
        : e_obj (obj), e_method (method), e_arg (arg) { }

      method_crefarg_elem (T& obj, void (T::*method) (const A&), const A& arg)
        : e_obj (&obj), e_method (method), e_arg (arg) { }

      // No copying!

      method_crefarg_elem (const method_crefarg_elem&) = delete;

      method_crefarg_elem operator = (const method_crefarg_elem&) = delete;

      void run (void) { (e_obj->*e_method) (e_arg); }

    private:

      T *e_obj;

      void (T::*e_method) (const A&);

      A e_arg;
    };

    /// An element for calling a member function with two arguments
    template <class T, class A, class B>
    class method_arg2_elem : public elem
    {
    public:
      method_arg2_elem (T *obj, void (T::*method) (const A&, const B&),
                        const A& arg_a, const B& arg_b)
        : e_obj (obj), e_method (method),
          e_arg_a (arg_a), e_arg_b (arg_b) { }

      void run (void) { (e_obj->*e_method) (e_arg_a, e_arg_b); }

    private:

      T *e_obj;
      void (T::*e_method) (const A&, const B&);
      A e_arg_a;
      B e_arg_b;

      // No copying!

      method_arg2_elem (const method_arg2_elem&);

      method_arg2_elem operator = (const method_arg2_elem&);
    };

    /// An element for calling a member function with three arguments
    template <class T, class A, class B, class C>
    class method_arg3_elem : public elem
    {
    public:
      method_arg3_elem (T *obj,
                        void (T::*method) (const A&, const B&, const C&),
                        const A& arg_a, const B& arg_b, const C& arg_c)
        : e_obj (obj), e_method (method),
          e_arg_a (arg_a), e_arg_b (arg_b), e_arg_c (arg_c)
      { }

      void run (void) { (e_obj->*e_method) (e_arg_a, e_arg_b, e_arg_c); }

    private:

      T *e_obj;
      void (T::*e_method) (const A&, const B&, const C&);
      A e_arg_a;
      B e_arg_b;
      C e_arg_c;

      // No copying!

      method_arg3_elem (const method_arg3_elem&);

      method_arg3_elem operator = (const method_arg3_elem&);
    };

    /// An element for calling a member function with three arguments
    template <class T, class A, class B, class C, class D>
    class method_arg4_elem : public elem
    {
    public:
      method_arg4_elem (T *obj,
                        void (T::*method) (const A&, const B&, const C&, const D&),
                        const A& arg_a, const B& arg_b, const C& arg_c,
                        const D& arg_d)
        : e_obj (obj), e_method (method),
          e_arg_a (arg_a), e_arg_b (arg_b), e_arg_c (arg_c), e_arg_d (arg_d)
      { }

      void run (void)
      {
        (e_obj->*e_method) (e_arg_a, e_arg_b, e_arg_c, e_arg_d);
      }

    private:

      T *e_obj;
      void (T::*e_method) (const A&, const B&, const C&, const D&);
      A e_arg_a;
      B e_arg_b;
      C e_arg_c;
      D e_arg_d;

      // No copying!

      method_arg4_elem (const method_arg4_elem&);

      method_arg4_elem operator = (const method_arg4_elem&);
    };

    // An element that stores arbitrary variable, and restores it.

    template <typename T>
    class restore_var_elem : public elem
    {
    public:

      restore_var_elem (T& ref, const T& val)
        : e_ptr (&ref), e_val (val) { }

      // No copying!

      restore_var_elem (const restore_var_elem&) = delete;

      restore_var_elem& operator = (const restore_var_elem&) = delete;

      void run (void) { *e_ptr = e_val; }

    private:

      T *e_ptr, e_val;
    };

    // Deletes a class allocated using new.

    template <typename T>
    class delete_ptr_elem : public elem
    {
    public:

      delete_ptr_elem (T *ptr)
        : e_ptr (ptr) { }

      // No copying!

      delete_ptr_elem (const delete_ptr_elem&) = delete;

      delete_ptr_elem operator = (const delete_ptr_elem&) = delete;

      void run (void) { delete e_ptr; }

    private:

      T *e_ptr;
    };

    action_container (void) { }

    // No copying!

    action_container (const action_container&) = delete;

    action_container& operator = (const action_container&) = delete;

    virtual ~action_container (void) = default;

    virtual void add (elem *new_elem) = 0;

    // Call to void func (void).
    void add_fcn (void (*fcn) (void))
    {
      add (new fcn_elem (fcn));
    }

    // Call to void func (T).
    template <typename T>
    void add_fcn (void (*action) (T), T val)
    {
      add (new fcn_arg_elem<T> (action, val));
    }

    // Call to void func (const T&).
    template <typename T>
    void add_fcn (void (*action) (const T&), const T& val)
    {
      add (new fcn_crefarg_elem<T> (action, val));
    }

    // Call to T::method (void).
    template <typename T>
    void add_method (T *obj, void (T::*method) (void))
    {
      add (new method_elem<T> (obj, method));
    }

    template <typename T>
    void add_method (T& obj, void (T::*method) (void))
    {
      add (new method_elem<T> (obj, method));
    }

    // Call to T::method (A).
    template <typename T, typename A>
    void add_method (T *obj, void (T::*method) (A), A arg)
    {
      add (new method_arg_elem<T, A> (obj, method, arg));
    }

    template <typename T, typename A>
    void add_method (T& obj, void (T::*method) (A), A arg)
    {
      add (new method_arg_elem<T, A> (obj, method, arg));
    }

    // Call to T::method (const A&).
    template <typename T, typename A>
    void add_method (T *obj, void (T::*method) (const A&), const A& arg)
    {
      add (new method_crefarg_elem<T, A> (obj, method, arg));
    }

    template <typename T, typename A>
    void add_method (T& obj, void (T::*method) (const A&), const A& arg)
    {
      add (new method_crefarg_elem<T, A> (obj, method, arg));
    }

    // Call to T::method (A, B).
    template <class T, class A, class B>
    void add_method (T *obj, void (T::*method) (const A&, const B&),
                     const A& arg_a, const B& arg_b)
    {
      add (new method_arg2_elem<T, A, B> (obj, method, arg_a, arg_b));
    }

    // Call to T::method (A, B, C).
    template <class T, class A, class B, class C>
    void add_method (T *obj,
                     void (T::*method) (const A&, const B&, const C&),
                     const A& arg_a, const B& arg_b, const C& arg_c)
    {
      add (new method_arg3_elem<T, A, B, C> (obj, method, arg_a,
                                             arg_b, arg_c));
    }

    // Call to T::method (A, B, C, D).
    template <class T, class A, class B, class C, class D>
    void add_method (T *obj,
                     void (T::*method) (const A&, const B&, const C&, const D&),
                     const A& arg_a, const B& arg_b,
                     const C& arg_c, const D& arg_d)
    {
      add (new method_arg4_elem<T, A, B, C, D> (obj, method, arg_a,
                                                arg_b, arg_c, arg_d));
    }

    // Call to delete (T*).

    template <typename T>
    void add_delete (T *obj)
    {
      add (new delete_ptr_elem<T> (obj));
    }

    // Protect any variable.
    template <typename T>
    void protect_var (T& var)
    {
      add (new restore_var_elem<T> (var, var));
    }

    // Protect any variable, value given.
    template <typename T>
    void protect_var (T& var, const T& val)
    {
      add (new restore_var_elem<T> (var, val));
    }

    operator bool (void) const { return ! empty (); }

    virtual void run_first (void) = 0;

    void run (size_t num)
    {
      if (num > size ())
        num = size ();

      for (size_t i = 0; i < num; i++)
        run_first ();
    }

    void run (void) { run (size ()); }

    virtual void discard_first (void) = 0;

    void discard (size_t num)
    {
      if (num > size ())
        num = size ();

      for (size_t i = 0; i < num; i++)
        discard_first ();
    }

    void discard (void) { discard (size ()); }

    virtual size_t size (void) const = 0;

    bool empty (void) const { return size () == 0; }
  };
}

#if defined (OCTAVE_USE_DEPRECATED_FUNCTIONS)

OCTAVE_DEPRECATED (4.4, "use 'octave::action_container' instead")
typedef octave::action_container action_container;

#endif

#endif