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                                 TORRENT_ASSERT(e.file_ptr->is_open());
  84                                 e.mode = m;
  85                         }
  86                         pt.replace(i, e);
  87                         return e.file_ptr;
  88                 }
  89                 // the file is not in our cache
  90                 if ((int)m_files.size() >= m_size)
  91                 {
  92                         // the file cache is at its maximum size, close
  93                         // the least recently used (lru) file from it
  94                         typedef nth_index<file_set, 1>::type lru_view;
  95                         lru_view& lt = get<1>(m_files);
  96                         lru_view::iterator i = lt.begin();
  97                         // the first entry in this view is the least recently used
  98                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
  99                         lt.erase(i);
 100                 }
 101                 lru_file_entry e;
 102                 e.file_ptr.reset(new (std::nothrow)file);
 103                 if (!e.file_ptr)
 104                 {
 105                         ec = error_code(ENOMEM, get_posix_category());
 106                         return e.file_ptr;
 107                 }
 108                 if (!e.file_ptr->open(p, m, ec))
 109                         return boost::shared_ptr<file>();
 110                 e.mode = m;
 111                 e.key = st;
 112                 e.file_path = p;
 113                 pt.insert(e);
 114                 TORRENT_ASSERT(e.file_ptr->is_open());
 115                 return e.file_ptr;
 116         }
 117
 118         void file_pool::release(fs::path const& p)
 119         {
 120                 boost::mutex::scoped_lock l(m_mutex);
 121
 122                 typedef nth_index<file_set, 0>::type path_view;
 123                 path_view& pt = get<0>(m_files);
 124                 path_view::iterator i = pt.find(p);
 125                 if (i != pt.end()) pt.erase(i);
 126         }
 127
 128         void file_pool::release(void* st)
 129         {
 130                 boost::mutex::scoped_lock l(m_mutex);
 131                 TORRENT_ASSERT(st != 0);
 132                 using boost::tie;
 133
 134                 typedef nth_index<file_set, 2>::type key_view;
 135                 key_view& kt = get<2>(m_files);
 136
 137                 key_view::iterator start, end;
 138                 tie(start, end) = kt.equal_range(st);
 139                 kt.erase(start, end);
 140         }
 141
 142         void file_pool::resize(int size)
 143         {
 144                 TORRENT_ASSERT(size > 0);
 145                 if (size == m_size) return;
 146                 boost::mutex::scoped_lock l(m_mutex);
 147                 m_size = size;
 148                 if (int(m_files.size()) <= m_size) return;
 149
 150                 // close the least recently used files
 151                 typedef nth_index<file_set, 1>::type lru_view;
 152                 lru_view& lt = get<1>(m_files);
 153                 lru_view::iterator i = lt.begin();
 154                 while (int(m_files.size()) > m_size)
 155                 {
 156                         // the first entry in this view is the least recently used
 157                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
 158                         lt.erase(i++);
 159                 }
 160         }
 161
 162 }