slot.h.m4

一个对象回调接口库

dnl Copyright 2002, The libsigc++ Development Team 
dnl 
dnl This library is free software; you can redistribute it and/or 
dnl modify it under the terms of the GNU Lesser General Public 
dnl License as published by the Free Software Foundation; either 
dnl version 2.1 of the License, or (at your option) any later version. 
dnl 
dnl This library is distributed in the hope that it will be useful, 
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of 
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
dnl Lesser General Public License for more details. 
dnl 
dnl You should have received a copy of the GNU Lesser General Public 
dnl License along with this library; if not, write to the Free Software 
dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
dnl
divert(-1)

include(template.macros.m4)

define([SLOT_N],[dnl
/** Converts an arbitrary functor to a unified type which is opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().dnl
FOR(1,$1,[
 * - @e T_arg%1 Argument type used in the definition of operator()(). The default @p nil means no argument.])
 *
 * To use simply assign the slot to the desired functor. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * You should use the more convenient unnumbered sigc::slot template.
 *
 * @ingroup slot
 */
/* TODO: Where put the following bit of information? I can't make any
 *       sense of the "because", by the way!
 *
 * Because slot is opaque, visit_each() will not visit its internal members.
 */
template <LIST(class T_return, LOOP(class T_arg%1, $1))>
class slot$1
  : public slot_base
{
public:
  typedef T_return result_type;
FOR(1, $1,[  typedef _R_(T_arg%1) arg%1_type_;
])

#ifndef DOXYGEN_SHOULD_SKIP_THIS
private:
  typedef internal::slot_rep rep_type;
public:
  typedef T_return (*call_type)(LIST(rep_type*, LOOP(arg%1_type_, $1)));
#endif

  /** Invoke the contained functor unless slot is in blocking state.dnl
FOR(1, $1,[
   * @param _A_a%1 Argument to be passed on to the functor.])
   * @return The return value of the functor invocation.
   */
  inline T_return operator()(LOOP(arg%1_type_ _A_a%1, $1)) const
    {
      if (!empty() && !blocked())
        return (reinterpret_cast<call_type>(rep_->call_))(LIST(rep_, LOOP(_A_a%1, $1)));
      return T_return();
    }

  inline slot$1() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desirer functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot$1(const T_functor& _A_func)
    : slot_base(new internal::typed_slot_rep<T_functor>(_A_func))
    { rep_->call_ = internal::slot_call$1<LIST(T_functor, T_return, LOOP(T_arg%1, $1))>::address(); }

  slot$1(const slot$1& src)
    : slot_base(src) {}

  /** Overrides this slot making a copy from another slot.
   * @param src The slot from which to make a copy.
   * @return @p this.
   */
  slot$1& operator=(const slot$1& src)
    { slot_base::operator=(src); return *this; }
};

])
define([SLOT],[dnl
ifelse($1, $2,[dnl
/** Convenience wrapper for the numbered sigc::slot# templates.
 * Slots convert arbitrary functors to unified types which are opaque.
 * sigc::slot itself is a functor or to be more precise a closure. It contains
 * a single, arbitrary functor (or closure) that is executed in operator()().
 *
 * The template arguments determine the function signature of operator()():
 * - @e T_return The return type of operator()().dnl
FOR(1,$1,[
 * - @e T_arg%1 Argument type used in the definition of operator()(). The default @p nil means no argument.])
 *
 * To use simply assign the slot to the desired functor. If the functor
 * is not compatible with the parameter list defined with the template
 * arguments compiler errors are triggered. When called the slot
 * will invoke the functor with minimal copies.
 * block() and unblock() can be used to block the functor's invocation
 * from operator()() temporarily.
 *
 * @par Example:
 *   @code
 *   void foo(int) {}
 *   sigc::slot<void, long> s = sigc::ptr_fun(&foo);
 *   s(19);
 *   @endcode
 *
 * @ingroup slot
 */
template <LIST(class T_return, LOOP(class T_arg%1 = nil, $1))>],[dnl
/** Convenience wrapper for the numbered sigc::slot$1 template.
 * See the base class for useful methods.
 * This is the template specialization of the unnumbered sigc::slot
 * template for $1 argument(s).
dnl *
dnl * @ingroup slot
 */
template <LIST(class T_return, LOOP(class T_arg%1, $1))>])
class slot ifelse($1, $2,,[<LIST(T_return, LOOP(T_arg%1,$1))>])
  : public slot$1<LIST(T_return, LOOP(T_arg%1, $1))>
{
public:
  typedef slot$1<LIST(T_return, LOOP(T_arg%1, $1))> parent_type;

  inline slot() {}

  /** Constructs a slot from an arbitrary functor.
   * @param _A_func The desirer functor the new slot should be assigned to.
   */
  template <class T_functor>
  slot(const T_functor& _A_func)
    : parent_type(_A_func) {}

  slot(const slot& src)
    : parent_type((const parent_type&)src) {}
};

])
define([SLOT_CALL],[dnl
/** Abstracts functor execution.
 * call_it() invokes a functor of type @e T_functor with a list of
 * parameters whose types are given by the template arguments.
 * address() forms a function pointer from call_it().
 *
 * The following template arguments are used:
 * - @e T_functor The functor type.
 * - @e T_return The return type of call_it().dnl
FOR(1,$1,[
 * - @e T_arg%1 Argument type used in the definition of call_it().])
 *
 */
template<LIST(class T_functor, class T_return, LOOP(class T_arg%1, $1))>
struct slot_call$1
{
  /** Invokes a functor of type @p T_functor.
   * @param rep slot_rep object that holds a functor of type @p T_functor.dnl
FOR(1, $1,[
   * @param _A_a%1 Argument to be passed on to the functor.])
   * @return The return values of the functor invocation.
   */
  static T_return call_it(LIST(slot_rep* rep, LOOP(_R_(T_arg%1) a_%1, $1)))
    {
      typedef typed_slot_rep<T_functor> typed_slot;
      typed_slot *typed_rep = static_cast<typed_slot*>(rep);dnl
ifelse($1,0,[
      return (typed_rep->functor_)();
],[
      return (typed_rep->functor_).SIGC_WORKAROUND_OPERATOR_PARENTHESES<LOOP([_R_(T_arg%1)],$1)>
               (LOOP(a_%1, $1));
])dnl
    }

  /** Forms a function pointer from call_it().
   * @return A function pointer formed from call_it().
   */
  static hook address() 
    { return reinterpret_cast<hook>(&call_it); }
};

])

divert(0)dnl
__FIREWALL__
#include <sigc++/trackable.h>
#include <sigc++/visit_each.h>
#include <sigc++/adaptors/adaptor_trait.h>
#include <sigc++/functors/slot_base.h>

namespace sigc {

namespace internal {

/** A typed slot_rep.
 * A typed slot_rep holds a functor that can be invoked from
 * slot::operator()(). visit_each() is used to visit the functor's
 * targets that inherit trackable recursively and register the
 * notification callback. Consequently the slot_rep object will be
 * notified when some referred object is destroyed or overwritten.
 */
template <class T_functor>
struct typed_slot_rep : public slot_rep
{
  typedef typed_slot_rep<T_functor> self;

  /* Use an adaptor type so that arguments can be passed as const references
   * through explicit template instantiation from slot_call#::call_it() */
  typedef typename adaptor_trait<T_functor>::adaptor_type adaptor_type;

  /** The functor contained by this slot_rep object. */
  adaptor_type functor_;

  /** Constructs an invalid typed slot_rep object.
   * The notification callback is registered using visit_each().
   * @param functor The functor contained by the new slot_rep object.
   */
  inline typed_slot_rep(const T_functor& functor)
    : slot_rep(0, &destroy, &dup), functor_(functor)
    { visit_each_type<trackable*>(slot_do_bind(this), functor_); }

  inline typed_slot_rep(const typed_slot_rep& cl)
    : slot_rep(cl.call_, &destroy, &dup), functor_(cl.functor_)
    { visit_each_type<trackable*>(slot_do_bind(this), functor_); }

  inline ~typed_slot_rep()
    {
      call_ = 0;
      destroy_ = 0;
      visit_each_type<trackable*>(slot_do_unbind(this), functor_);
    }

  /** Detaches the stored functor from the other referred trackables and destroys it.
   * This does not destroy the base slot_rep object.
   */
  static void* destroy(void* data)
    {
      self* self_ = static_cast<self*>((slot_rep*)data);
      self_->call_ = 0;
      self_->destroy_ = 0;
      visit_each_type<trackable*>(slot_do_unbind(self_), self_->functor_);
      self_->functor_.~adaptor_type();
      /* don't call disconnect() here: destroy() is either called
       * a) from the parent itself (in which case disconnect() leads to a segfault) or
       * b) from a parentless slot (in which case disconnect() does nothing)
       */
      return 0;
    }

  /** Makes a deep copy of the slot_rep object.
   * Deep copy means that the notification callback of the new
   * slot_rep object is registered in the referred trackables.
   * @return A deep copy of the slot_rep object.
   */
  static void* dup(void* data)
    {
      slot_rep* rep_ = (slot_rep*)data;
      return static_cast<slot_rep*>(new self(*static_cast<self*>(rep_)));
    }
};


FOR(0,CALL_SIZE,[[SLOT_CALL(%1)]])dnl
} /* namespace internal */


FOR(0,CALL_SIZE,[[SLOT_N(%1,CALL_SIZE)]])
SLOT(CALL_SIZE,CALL_SIZE)
FOR(0,eval(CALL_SIZE-1),[[SLOT(%1,CALL_SIZE)]])

} /* namespace sigc */