Line data    Source code

       1              : /* Loosely-coupled notifications via the Publish-Subscribe pattern.
       2              :    Copyright (C) 2025 Free Software Foundation, Inc.
       3              :    Contributed by David Malcolm <dmalcolm@redhat.com>.
       4              : 
       5              : This file is part of GCC.
       6              : 
       7              : GCC is free software; you can redistribute it and/or modify it under
       8              : the terms of the GNU General Public License as published by the Free
       9              : Software Foundation; either version 3, or (at your option) any later
      10              : version.
      11              : 
      12              : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      13              : WARRANTY; without even the implied warranty of MERCHANTABILITY or
      14              : FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      15              : for more details.
      16              : 
      17              : You should have received a copy of the GNU General Public License
      18              : along with GCC; see the file COPYING3.  If not see
      19              : <http://www.gnu.org/licenses/>.  */
      20              : 
      21              : #ifndef GCC_PUB_SUB_H
      22              : #define GCC_PUB_SUB_H
      23              : 
      24              : namespace pub_sub {
      25              : 
      26              : template <typename Subscriber>
      27       256629 : class channel
      28              : {
      29              : public:
      30              :   using subscriber = Subscriber;
      31              : 
      32              :   // A node within the std::list
      33              :   using subscription = typename std::list<subscriber *>::iterator;
      34              : 
      35              :   /* Return this if this channel has subscribers, or nullptr if
      36              :      there are none.  */
      37              :   const channel *
      38    784626038 :   get_if_active () const
      39              :   {
      40    784626038 :     if (m_subscribers.empty ())
      41              :       return nullptr;
      42              :     return this;
      43              :   }
      44              : 
      45              :   template <typename Message>
      46          610 :   void publish (const Message &m) const
      47              :   {
      48         1518 :     for (auto sub : m_subscribers)
      49          908 :       sub->on_message (m);
      50          610 :   }
      51              : 
      52              :   subscription
      53           26 :   add_subscriber (subscriber &s)
      54              :   {
      55           26 :     return m_subscribers.insert (m_subscribers.end (), &s);
      56              :   }
      57              :   void unsubscribe (subscription s)
      58              :   {
      59              :     m_subscribers.remove (s);
      60              :   }
      61              : 
      62              : private:
      63              :   std::list<subscriber *> m_subscribers;
      64              : };
      65              : 
      66              : } // namespace pub_sub
      67              : 
      68              : #endif /* GCC_PUB_SUB_H */