src/file_pool.cpp

   1 /*
   2
   3 Copyright (c) 2006, Arvid Norberg
   4 All rights reserved.
   5
   6 Redistribution and use in source and binary forms, with or without
   7 modification, are permitted provided that the following conditions
   8 are met:
   9
  10     * Redistributions of source code must retain the above copyright
  11       notice, this list of conditions and the following disclaimer.
  12     * Redistributions in binary form must reproduce the above copyright
  13       notice, this list of conditions and the following disclaimer in
  14       the documentation and/or other materials provided with the distribution.
  15     * Neither the name of the author nor the names of its
  16       contributors may be used to endorse or promote products derived
  17       from this software without specific prior written permission.
  18
  19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  20 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  23 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29 POSSIBILITY OF SUCH DAMAGE.
  30
  31 */
  32
  33 #include <boost/version.hpp>
  34 #include "libtorrent/pch.hpp"
  35 #include "libtorrent/file_pool.hpp"
  36 #include "libtorrent/error_code.hpp"
  37
  38 #include <iostream>
  39
  40 namespace libtorrent
  41 {
  42         using boost::multi_index::nth_index;
  43         using boost::multi_index::get;
  44
  45         boost::shared_ptr<file> file_pool::open_file(void* st, fs::path const& p
  46                 , file::open_mode m, error_code& ec)
  47         {
  48                 TORRENT_ASSERT(st != 0);
  49                 TORRENT_ASSERT(p.is_complete());
  50                 TORRENT_ASSERT(m == file::in || m == (file::in | file::out));
  51                 boost::mutex::scoped_lock l(m_mutex);
  52                 typedef nth_index<file_set, 0>::type path_view;
  53                 path_view& pt = get<0>(m_files);
  54                 path_view::iterator i = pt.find(p);
  55                 if (i != pt.end())
  56                 {
  57                         lru_file_entry e = *i;
  58                         e.last_use = time_now();
  59
  60                         if (e.key != st)
  61                         {
  62                                 // this means that another instance of the storage
  63                                 // is using the exact same file.
  64 #if BOOST_VERSION >= 103500
  65                                 ec = error_code(errors::file_collision, libtorrent_category);
  66 #endif
  67                                 return boost::shared_ptr<file>();
  68                         }
  69
  70                         e.key = st;
  71                         if ((e.mode & m) != m)
  72                         {
  73                                 // close the file before we open it with
  74                                 // the new read/write privilages
  75                                 i->file_ptr.reset();
  76                                 TORRENT_ASSERT(e.file_ptr.unique());
  77                                 e.file_ptr->close();
  78                                 if (!e.file_ptr->open(p, m, ec))
  79                                 {
  80                                         m_files.erase(i);
  81                                         return boost::shared_ptr<file>();
  82                                 }
  83                                 e.mode = m;
  84                         }
  85                         pt.replace(i, e);
  86                         return e.file_ptr;
  87                 }
  88                 // the file is not in our cache
  89                 if ((int)m_files.size() >= m_size)
  90                 {
  91                         // the file cache is at its maximum size, close
  92                         // the least recently used (lru) file from it
  93                         typedef nth_index<file_set, 1>::type lru_view;
  94                         lru_view& lt = get<1>(m_files);
  95                         lru_view::iterator i = lt.begin();
  96                         // the first entry in this view is the least recently used
  97                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
  98                         lt.erase(i);
  99                 }
 100                 lru_file_entry e;
 101                 e.file_ptr.reset(new (std::nothrow)file);
 102                 if (!e.file_ptr)
 103                 {
 104                         ec = error_code(ENOMEM, get_posix_category());
 105                         return e.file_ptr;
 106                 }
 107                 if (!e.file_ptr->open(p, m, ec))
 108                         return boost::shared_ptr<file>();
 109                 e.mode = m;
 110                 e.key = st;
 111                 e.file_path = p;
 112                 pt.insert(e);
 113                 return e.file_ptr;
 114         }
 115
 116         void file_pool::release(fs::path const& p)
 117         {
 118                 boost::mutex::scoped_lock l(m_mutex);
 119
 120                 typedef nth_index<file_set, 0>::type path_view;
 121                 path_view& pt = get<0>(m_files);
 122                 path_view::iterator i = pt.find(p);
 123                 if (i != pt.end()) pt.erase(i);
 124         }
 125
 126         void file_pool::release(void* st)
 127         {
 128                 boost::mutex::scoped_lock l(m_mutex);
 129                 TORRENT_ASSERT(st != 0);
 130                 using boost::tie;
 131
 132                 typedef nth_index<file_set, 2>::type key_view;
 133                 key_view& kt = get<2>(m_files);
 134
 135                 key_view::iterator start, end;
 136                 tie(start, end) = kt.equal_range(st);
 137                 kt.erase(start, end);
 138         }
 139
 140         void file_pool::resize(int size)
 141         {
 142                 TORRENT_ASSERT(size > 0);
 143                 if (size == m_size) return;
 144                 boost::mutex::scoped_lock l(m_mutex);
 145                 m_size = size;
 146                 if (int(m_files.size()) <= m_size) return;
 147
 148                 // close the least recently used files
 149                 typedef nth_index<file_set, 1>::type lru_view;
 150                 lru_view& lt = get<1>(m_files);
 151                 lru_view::iterator i = lt.begin();
 152                 while (int(m_files.size()) > m_size)
 153                 {
 154                         // the first entry in this view is the least recently used
 155                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
 156                         lt.erase(i++);
 157                 }
 158         }
 159
 160 }