Link.hh

Go to the documentation of this file.

// -*- mode:c++;tab-width:2;indent-tabs-mode:t;show-trailing-whitespace:t;rm-trailing-spaces:t -*-
// vi: set ts=2 noet:
//
// (c) Copyright Rosetta Commons Member Institutions.
// (c) This file is part of the Rosetta software suite and is made available under license.
// (c) The Rosetta software is developed by the contributing members of the Rosetta Commons.
// (c) For more information, see http://www.rosettacommons.org. Questions about this can be
// (c) addressed to University of Washington UW TechTransfer, email: license@u.washington.edu.
// (C) 199x-2009 University of Washington
// (C) 199x-2009 University of California Santa Cruz
// (C) 199x-2009 University of California San Francisco
// (C) 199x-2009 Johns Hopkins University
// (C) 199x-2009 University of North Carolina, Chapel Hill
// (C) 199x-2009 Vanderbilt University

/// @file   utility/signals/Link.hh
/// @brief  class storing the link between observers and subjects
/// @author Yih-En Andrew Ban (yab@u.washington.edu)

#ifndef INCLUDED_utility_signals_Link_hh
#define INCLUDED_utility_signals_Link_hh


// unit headers
#include <utility/signals/Link.fwd.hh>

// package headers
#include <utility/signals/LinkUnit.hh>
#include <utility/pointer/owning_ptr.hh>
#include <utility/assert.hh>


namespace utility {
namespace signals {


/// @brief interface wrapper around utility::signals::LinkUnit
/// @details Can be used to manage the link between Subject
///  and Observer.  Signals can be temporarily blocked and the
///  connection can be invalidated (disconnected) by the user.
///  If a Subject is destroyed or a manual disconnect is called
///  via the SignalHub, the Link will automatically become invalidated.
/// @remarks Returned by utility::signals::SignalHub upon connection.
class Link {


private: // typedefs


  typedef utility::pointer::shared_ptr< LinkUnit > LinkUnitOP;


public: // construct/destruct


  /// @brief default constructor
  inline
  Link() {}


  /// @brief LinkUnit constructor
  inline
  Link( LinkUnitOP unit ) :
    unit_( unit ) // must store the same LinkUnit
  {}


  /// @brief copy constructor
  inline
  Link( Link const & rval ) :
    unit_( rval.unit_ ) // must store the same LinkUnit
  {}


  /// @brief default destructor
  inline
  ~Link() {}


public: // copy assignment


  /// @brief copy assignment
  Link & operator =( Link const & rval ) {
    if ( this != &rval ) {
      unit_ = rval.unit_; // must store the same LinkUnit
    }

    return *this;
  }


public: // operators


  /// @brief equality comparison
  bool
  operator ==( Link const & rval ) {
    return unit_.get() == rval.unit_.get();
  }


public: // interface


  /// @brief link empty?
  inline
  bool empty() const {
    return ( unit_ == NULL );
  }


  /// @brief link still valid?
  /// @return false if link invalid or empty, otherwise true
  inline
  bool valid() const {
    if ( unit_ ) {
      return unit_->valid;
    }
    return false;
  }


  /// @brief cut the connection, safe to call even when link is empty
  inline
  void invalidate() {
    if ( unit_ ) {
      unit_->valid = false;
    }
  }


  /// @brief link blocked?
  /// @brief true if link is blocked or empty, otherwise false
  inline
  bool blocked() const {
    if ( unit_ ) {
      return unit_->blocked;
    }
    return true;
  }


  /// @brief locally block the link
  inline
  void block() {
    if ( unit_ ) {
      unit_->blocked = true;
    }
  }


  /// @brief locally unblock the link
  inline
  void unblock() {
    if ( unit_ ) {
      unit_->blocked = false;
    }
  }


private: // data


  LinkUnitOP unit_;

};


} // namespace signals
} // namespace utility

#endif /* INCLUDED_utility_signals_Link_HH */