ceph/src/boost/libs/spirit/include/boost/spirit/home/support/iterators/detail/first_owner_policy.hpp

   1 //  Copyright (c) 2001, Daniel C. Nuffer
   2 //  Copyright (c) 2001-2011 Hartmut Kaiser
   3 //
   4 //  Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #if !defined(BOOST_SPIRIT_ITERATOR_FIRST_OWNER_POLICY_MAR_16_2007_1108AM)
   8 #define BOOST_SPIRIT_ITERATOR_FIRST_OWNER_POLICY_MAR_16_2007_1108AM
   9
  10 #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
  11 #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
  12
  13 namespace boost { namespace spirit { namespace iterator_policies
  14 {
  15     ///////////////////////////////////////////////////////////////////////////
  16     //  class first_owner
  17     //  Implementation of an OwnershipPolicy used by multi_pass
  18     //  This ownership policy dictates that the first iterator created will
  19     //  determine the lifespan of the shared components.  This works well for
  20     //  spirit, since no dynamic allocation of iterators is done, and all
  21     //  copies are make on the stack.
  22     //
  23     //  There is a caveat about using this policy together with the std_deque
  24     //  StoragePolicy. Since first_owner always returns false from unique(),
  25     //  std_deque will only release the queued data if clear_queue() is called.
  26     ///////////////////////////////////////////////////////////////////////////
  27     struct first_owner
  28     {
  29         ///////////////////////////////////////////////////////////////////////
  30         struct unique : detail::default_ownership_policy
  31         {
  32             unique() : first(true) {}
  33             unique(unique const&) : first(false) {}
  34
  35             // return true to indicate deletion of resources
  36             template <typename MultiPass>
  37             static bool release(MultiPass& mp)
  38             {
  39                 return mp.first;
  40             }
  41
  42             // use swap from default policy
  43             // if we're the first, we still remain the first, even if assigned
  44             // to, so don't swap first.  swap is only called from operator=
  45
  46             template <typename MultiPass>
  47             static bool is_unique(MultiPass const&)
  48             {
  49                 return false; // no way to know, so always return false
  50             }
  51
  52         protected:
  53             bool first;
  54         };
  55
  56         ////////////////////////////////////////////////////////////////////////
  57         struct shared {};   // no shared data
  58     };
  59
  60 }}}
  61
  62 #endif