ceph/src/boost/libs/signals2/example/doc_view_acm_deconstruct.cpp

   1 // Document/View sample for Boost.Signals2.
   2 // Expands on doc_view_acm.cpp example by using boost::signals2::deconstruct
   3 // as a post-constructing factory function.
   4 //
   5 // Copyright Keith MacDonald 2005.
   6 // Copyright Frank Mori Hess 2009.
   7 //
   8 // Use, modification and
   9 // distribution is subject to the Boost Software License, Version
  10 // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  11 // http://www.boost.org/LICENSE_1_0.txt)
  12 // For more information, see http://www.boost.org
  13
  14 #include <iostream>
  15 #include <string>
  16 #include <boost/bind/bind.hpp>
  17 #include <boost/ref.hpp>
  18 #include <boost/signals2/deconstruct.hpp>
  19 #include <boost/signals2/signal.hpp>
  20 #include <boost/shared_ptr.hpp>
  21
  22 class Document
  23 {
  24 public:
  25   typedef boost::signals2::signal<void ()>  signal_t;
  26
  27 public:
  28   Document()
  29   {}
  30
  31   /* Connect a slot to the signal which will be emitted whenever
  32     text is appended to the document. */
  33   boost::signals2::connection connect(const signal_t::slot_type &subscriber)
  34   {
  35     return m_sig.connect(subscriber);
  36   }
  37
  38   void append(const char* s)
  39   {
  40     m_text += s;
  41     m_sig();
  42   }
  43
  44   const std::string& getText() const
  45   {
  46     return m_text;
  47   }
  48
  49 private:
  50   signal_t    m_sig;
  51   std::string m_text;
  52 };
  53
  54 class TextView
  55 {
  56 public:
  57   /* This adl_postconstruct function will be found
  58   via argument-dependent lookup when using boost::signals2::deconstruct. */
  59   template<typename T>
  60     friend void adl_postconstruct(const boost::shared_ptr<T> &view_sp, TextView *view, Document& doc)
  61   {
  62     view->m_document = &doc;
  63     {
  64       typedef Document::signal_t::slot_type slot_type;
  65       slot_type myslot(&TextView::refresh, view);
  66       doc.connect(myslot.track(view_sp));
  67     }
  68   }
  69
  70   void refresh() const
  71   {
  72     std::cout << "TextView: " << m_document->getText() << std::endl;
  73   }
  74 private:
  75   // give boost::signals2::deconstruct access to private constructor
  76   friend class boost::signals2::deconstruct_access;
  77   // private constructor to force use of deconstruct
  78   TextView() : m_document(0)
  79   {}
  80
  81   Document*               m_document;
  82 };
  83
  84 class HexView
  85 {
  86 public:
  87   /* This adl_postconstruct function will be found
  88   via argument-dependent lookup when using boost::signals2::deconstruct. */
  89   template<typename T>
  90     friend void adl_postconstruct(const boost::shared_ptr<T> &view_sp, HexView *view, Document& doc)
  91   {
  92     view->m_document = &doc;
  93     {
  94       typedef Document::signal_t::slot_type slot_type;
  95       slot_type myslot(&HexView::refresh, view);
  96       doc.connect(myslot.track(view_sp));
  97     }
  98   }
  99
 100   void refresh() const
 101   {
 102     const std::string&  s = m_document->getText();
 103
 104     std::cout << "HexView:";
 105
 106     for (std::string::const_iterator it = s.begin(); it != s.end(); ++it)
 107       std::cout << ' ' << std::hex << static_cast<int>(*it);
 108
 109     std::cout << std::endl;
 110   }
 111 private:
 112   // give boost::signals2::deconstruct access to private constructor
 113   friend class boost::signals2::deconstruct_access;
 114   // private constructor to force use of deconstruct
 115   HexView(): m_document(0)
 116   {}
 117
 118   Document*               m_document;
 119 };
 120
 121 namespace bs2 = boost::signals2;
 122
 123 int main(int argc, char* argv[])
 124 {
 125   Document    doc;
 126   boost::shared_ptr<TextView> v1 = bs2::deconstruct<TextView>().postconstruct(boost::ref(doc));
 127   boost::shared_ptr<HexView> v2 = bs2::deconstruct<HexView>().postconstruct(boost::ref(doc));
 128
 129   doc.append(argc >= 2 ? argv[1] : "Hello world!");
 130
 131   v2.reset(); // destroy the HexView, automatically disconnecting
 132   doc.append("  HexView should no longer be connected.");
 133
 134   return 0;
 135 }