Line data    Source code

       1             : //
       2             : // Author: Vladimir Migashko <migashko@gmail.com>, (C) 2012
       3             : //
       4             : // Copyright: See COPYING file that comes with this distribution
       5             : //
       6             : 
       7             : #ifndef VSET_VSET_BUFFER_PERSISTENT_MMAP_AD_TRUNCATE_HPP
       8             : #define VSET_VSET_BUFFER_PERSISTENT_MMAP_AD_TRUNCATE_HPP
       9             : 
      10             : #include <vset/buffer/tags.hpp>
      11             : #include <vset/buffer/persistent/tags.hpp>
      12             : #include <unistd.h>
      13             : #include <sys/mman.h>
      14             : 
      15             : 
      16             : namespace vset { namespace buffer { namespace persistent{ namespace mmap{
      17             : 
      18           9 : struct ad_truncate
      19             : {
      20             :   template<typename T>
      21          24 :   void operator()( T& t, size_t size)
      22             :   {
      23             :     typedef typename T::aspect::template advice_cast<_head_type_>::type head_type;
      24          24 :     size_t capacity = t.get_aspect().template get<_capacity_>()(t);
      25          24 :     size_t oldsize = sizeof(head_type) + capacity;
      26          24 :     size_t newsize = sizeof(head_type) + size;
      27             : 
      28          24 :     t.get_aspect().template get<_resize_file_>()(t, newsize);
      29          24 :     char* olddata = t.get_aspect().template get<_buffer_>();
      30          24 :     char* data = static_cast<char*>( ::mremap( olddata, oldsize, newsize, MREMAP_MAYMOVE) );
      31          24 :     if ( data == MAP_FAILED)
      32           0 :       throw std::runtime_error(strerror(errno));
      33             : 
      34          24 :     if ( oldsize < newsize )
      35          21 :       ::memset( data + oldsize, 0, newsize - oldsize);
      36             :     
      37          24 :     t.get_aspect().template get<_buffer_>() = data;
      38          24 :     t.get_aspect().template get<_buffer_size_>() = newsize;
      39          24 :     t.get_aspect().template get<_head_>()(t)->set_capacity(size);
      40          24 :     t.get_aspect().template get<_capacity_value_>() = size;
      41             : 
      42          24 :     if ( size <= capacity )
      43             :     {
      44           3 :       t.get_aspect().template get<_head_>()(t)->set_size(size);
      45           3 :       t.get_aspect().template get<_size_value_>() = size;
      46             :     }
      47          24 :     t.get_aspect().template get<_sync_>()(t, 0, 0);
      48          24 :   }
      49             : };
      50             : 
      51             : }}}}
      52             : 
      53             : #endif