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 #if BOOST_VERSION >= 103500
  46         struct file_pool_error_category : boost::system::error_category
  47         {
  48                 virtual const char* name() const { return "file pool error"; }
  49                 virtual std::string message(int ev) const
  50                 {
  51                         static char const* msgs[] =
  52                         { "no error", "torrent file collides with file from another torrent" };
  53                         if (ev < 0 || ev >= sizeof(msgs)/sizeof(msgs[0]))
  54                                 return "Unknown error";
  55                         return msgs[ev];
  56                 }
  57                 virtual boost::system::error_condition default_error_condition(int ev) const
  58                 {
  59                         return boost::system::error_condition(ev, *this);
  60                 }
  61                 virtual bool equivalent(int code, boost::system::error_condition const& condition) const
  62                 {
  63                         return default_error_condition(code) == condition;
  64                 }
  65                 virtual bool equivalent(boost::system::error_code const& code, int condition ) const
  66                 {
  67                         return *this == code.category() && code.value() == condition;
  68                 }
  69         };
  70
  71         file_pool_error_category file_pool_category;
  72
  73 #endif
  74
  75         boost::shared_ptr<file> file_pool::open_file(void* st, fs::path const& p
  76                 , file::open_mode m, error_code& ec)
  77         {
  78                 TORRENT_ASSERT(st != 0);
  79                 TORRENT_ASSERT(p.is_complete());
  80                 TORRENT_ASSERT(m == file::in || m == (file::in | file::out));
  81                 boost::mutex::scoped_lock l(m_mutex);
  82                 typedef nth_index<file_set, 0>::type path_view;
  83                 path_view& pt = get<0>(m_files);
  84                 path_view::iterator i = pt.find(p);
  85                 if (i != pt.end())
  86                 {
  87                         lru_file_entry e = *i;
  88                         e.last_use = time_now();
  89
  90                         if (e.key != st)
  91                         {
  92                                 // this means that another instance of the storage
  93                                 // is using the exact same file.
  94 #if BOOST_VERSION >= 103500
  95                                 ec = error_code(1, file_pool_category);
  96 #endif
  97                                 return boost::shared_ptr<file>();
  98                         }
  99
 100                         e.key = st;
 101                         if ((e.mode & m) != m)
 102                         {
 103                                 // close the file before we open it with
 104                                 // the new read/write privilages
 105                                 i->file_ptr.reset();
 106                                 TORRENT_ASSERT(e.file_ptr.unique());
 107                                 e.file_ptr->close();
 108                                 if (!e.file_ptr->open(p, m, ec))
 109                                 {
 110                                         m_files.erase(i);
 111                                         return boost::shared_ptr<file>();
 112                                 }
 113                                 e.mode = m;
 114                         }
 115                         pt.replace(i, e);
 116                         return e.file_ptr;
 117                 }
 118                 // the file is not in our cache
 119                 if ((int)m_files.size() >= m_size)
 120                 {
 121                         // the file cache is at its maximum size, close
 122                         // the least recently used (lru) file from it
 123                         typedef nth_index<file_set, 1>::type lru_view;
 124                         lru_view& lt = get<1>(m_files);
 125                         lru_view::iterator i = lt.begin();
 126                         // the first entry in this view is the least recently used
 127                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
 128                         lt.erase(i);
 129                 }
 130                 lru_file_entry e;
 131                 e.file_ptr.reset(new (std::nothrow)file);
 132                 if (!e.file_ptr)
 133                 {
 134                         ec = error_code(ENOMEM, get_posix_category());
 135                         return e.file_ptr;
 136                 }
 137                 if (!e.file_ptr->open(p, m, ec))
 138                         return boost::shared_ptr<file>();
 139                 e.mode = m;
 140                 e.key = st;
 141                 e.file_path = p;
 142                 pt.insert(e);
 143                 return e.file_ptr;
 144         }
 145
 146         void file_pool::release(fs::path const& p)
 147         {
 148                 boost::mutex::scoped_lock l(m_mutex);
 149
 150                 typedef nth_index<file_set, 0>::type path_view;
 151                 path_view& pt = get<0>(m_files);
 152                 path_view::iterator i = pt.find(p);
 153                 if (i != pt.end()) pt.erase(i);
 154         }
 155
 156         void file_pool::release(void* st)
 157         {
 158                 boost::mutex::scoped_lock l(m_mutex);
 159                 TORRENT_ASSERT(st != 0);
 160                 using boost::tie;
 161
 162                 typedef nth_index<file_set, 2>::type key_view;
 163                 key_view& kt = get<2>(m_files);
 164
 165                 key_view::iterator start, end;
 166                 tie(start, end) = kt.equal_range(st);
 167                 kt.erase(start, end);
 168         }
 169
 170         void file_pool::resize(int size)
 171         {
 172                 TORRENT_ASSERT(size > 0);
 173                 if (size == m_size) return;
 174                 boost::mutex::scoped_lock l(m_mutex);
 175                 m_size = size;
 176                 if (int(m_files.size()) <= m_size) return;
 177
 178                 // close the least recently used files
 179                 typedef nth_index<file_set, 1>::type lru_view;
 180                 lru_view& lt = get<1>(m_files);
 181                 lru_view::iterator i = lt.begin();
 182                 while (int(m_files.size()) > m_size)
 183                 {
 184                         // the first entry in this view is the least recently used
 185                         TORRENT_ASSERT(lt.size() == 1 || (i->last_use <= boost::next(i)->last_use));
 186                         lt.erase(i++);
 187                 }
 188         }
 189
 190 }