premiere-libtorrent/src/file_pool.cpp

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/*
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Copyright (c) 2006-2014, Arvid Norberg
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the distribution.
* Neither the name of the author nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#include <boost/version.hpp>
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#include <boost/bind.hpp>
#include "libtorrent/pch.hpp"
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#include "libtorrent/assert.hpp"
#include "libtorrent/file_pool.hpp"
#include "libtorrent/error_code.hpp"
#include "libtorrent/file_storage.hpp" // for file_entry
namespace libtorrent
{
file_pool::file_pool(int size)
: m_size(size)
, m_low_prio_io(true)
#if TORRENT_CLOSE_MAY_BLOCK
, m_stop_thread(false)
, m_closer_thread(boost::bind(&file_pool::closer_thread_fun, this))
#endif
{
#if TORRENT_USE_ASSERTS
m_in_use = 1337;
#endif
}
file_pool::~file_pool()
{
#if TORRENT_USE_ASSERTS
m_in_use = 0;
#endif
#if TORRENT_CLOSE_MAY_BLOCK
mutex::scoped_lock l(m_closer_mutex);
m_stop_thread = true;
l.unlock();
// wait for hte closer thread to finish closing all files
m_closer_thread.join();
#endif
}
#if TORRENT_CLOSE_MAY_BLOCK
void file_pool::closer_thread_fun()
{
for (;;)
{
mutex::scoped_lock l(m_closer_mutex);
if (m_stop_thread)
{
l.unlock();
m_queued_for_close.clear();
return;
}
// find a file that doesn't have any other threads referencing
// it. Since only those files can be closed in this thead
std::vector<boost::intrusive_ptr<file> >::iterator i = std::find_if(
m_queued_for_close.begin(), m_queued_for_close.end()
, boost::bind(&file::refcount, boost::bind(&boost::intrusive_ptr<file>::get, _1)) == 1);
if (i == m_queued_for_close.end())
{
l.unlock();
// none of the files are ready to be closed yet
// because they're still in use by other threads
// hold off for a while
sleep(100);
}
else
{
// ok, first pull the file out of the queue, release the mutex
// (since closing the file may block) and then close it.
boost::intrusive_ptr<file> f = *i;
m_queued_for_close.erase(i);
l.unlock();
f->close();
}
}
}
#endif
#ifdef TORRENT_WINDOWS
void set_low_priority(boost::intrusive_ptr<file> const& f)
{
// file prio is only supported on vista and up
// so load the functions dynamically
typedef enum _FILE_INFO_BY_HANDLE_CLASS {
FileBasicInfo,
FileStandardInfo,
FileNameInfo,
FileRenameInfo,
FileDispositionInfo,
FileAllocationInfo,
FileEndOfFileInfo,
FileStreamInfo,
FileCompressionInfo,
FileAttributeTagInfo,
FileIdBothDirectoryInfo,
FileIdBothDirectoryRestartInfo,
FileIoPriorityHintInfo,
FileRemoteProtocolInfo,
MaximumFileInfoByHandleClass
} FILE_INFO_BY_HANDLE_CLASS, *PFILE_INFO_BY_HANDLE_CLASS;
typedef enum _PRIORITY_HINT {
IoPriorityHintVeryLow = 0,
IoPriorityHintLow,
IoPriorityHintNormal,
MaximumIoPriorityHintType
} PRIORITY_HINT;
typedef struct _FILE_IO_PRIORITY_HINT_INFO {
PRIORITY_HINT PriorityHint;
} FILE_IO_PRIORITY_HINT_INFO, *PFILE_IO_PRIORITY_HINT_INFO;
typedef BOOL (WINAPI *SetFileInformationByHandle_t)(HANDLE hFile, FILE_INFO_BY_HANDLE_CLASS FileInformationClass, LPVOID lpFileInformation, DWORD dwBufferSize);
static SetFileInformationByHandle_t SetFileInformationByHandle = NULL;
static bool failed_kernel_load = false;
if (failed_kernel_load) return;
if (SetFileInformationByHandle == NULL)
{
HMODULE kernel32 = LoadLibraryA("kernel32.dll");
if (kernel32 == NULL)
{
failed_kernel_load = true;
return;
}
SetFileInformationByHandle = (SetFileInformationByHandle_t)GetProcAddress(kernel32, "SetFileInformationByHandle");
if (SetFileInformationByHandle == NULL)
{
failed_kernel_load = true;
return;
}
}
TORRENT_ASSERT(SetFileInformationByHandle);
FILE_IO_PRIORITY_HINT_INFO io_hint;
io_hint.PriorityHint = IoPriorityHintLow;
SetFileInformationByHandle(f->native_handle(),
FileIoPriorityHintInfo, &io_hint, sizeof(io_hint));
}
#endif // TORRENT_WINDOWS
boost::intrusive_ptr<file> file_pool::open_file(void* st, std::string const& p
, int file_index, file_storage const& fs, int m, error_code& ec)
{
TORRENT_ASSERT(st != 0);
TORRENT_ASSERT(is_complete(p));
TORRENT_ASSERT((m & file::rw_mask) == file::read_only
|| (m & file::rw_mask) == file::read_write);
mutex::scoped_lock l(m_mutex);
TORRENT_ASSERT(m_in_use == 1337);
file_set::iterator i = m_files.find(std::make_pair(st, file_index));
if (i != m_files.end())
{
lru_file_entry& e = i->second;
e.last_use = time_now();
if (e.key != st && ((e.mode & file::rw_mask) != file::read_only
|| (m & file::rw_mask) != file::read_only))
{
// this means that another instance of the storage
// is using the exact same file.
#if BOOST_VERSION >= 103500
ec = errors::file_collision;
#endif
return boost::intrusive_ptr<file>();
}
e.key = st;
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// if we asked for a file in write mode,
// and the cached file is is not opened in
// write mode, re-open it
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if ((((e.mode & file::rw_mask) != file::read_write)
&& ((m & file::rw_mask) == file::read_write))
|| (e.mode & file::no_buffer) != (m & file::no_buffer)
|| (e.mode & file::random_access) != (m & file::random_access))
{
// close the file before we open it with
// the new read/write privilages
TORRENT_ASSERT(e.file_ptr->refcount() == 1);
#if TORRENT_CLOSE_MAY_BLOCK
mutex::scoped_lock l(m_closer_mutex);
m_queued_for_close.push_back(e.file_ptr);
l.unlock();
e.file_ptr = new file;
#else
e.file_ptr->close();
#endif
std::string full_path = fs.file_path(file_index, p);
if (!e.file_ptr->open(full_path, m, ec))
{
m_files.erase(i);
return boost::intrusive_ptr<file>();
}
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#ifdef TORRENT_WINDOWS
if (m_low_prio_io)
set_low_priority(e.file_ptr);
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#endif
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TORRENT_ASSERT(e.file_ptr->is_open());
e.mode = m;
}
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TORRENT_ASSERT((e.mode & file::no_buffer) == (m & file::no_buffer));
return e.file_ptr;
}
// the file is not in our cache
if ((int)m_files.size() >= m_size)
{
// the file cache is at its maximum size, close
// the least recently used (lru) file from it
remove_oldest();
}
lru_file_entry e;
e.file_ptr.reset(new (std::nothrow)file);
if (!e.file_ptr)
{
ec = error_code(ENOMEM, get_posix_category());
return e.file_ptr;
}
std::string full_path = fs.file_path(file_index, p);
if (!e.file_ptr->open(full_path, m, ec))
return boost::intrusive_ptr<file>();
#ifdef TORRENT_WINDOWS
if (m_low_prio_io)
set_low_priority(e.file_ptr);
#endif
e.mode = m;
e.key = st;
m_files.insert(std::make_pair(std::make_pair(st, file_index), e));
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TORRENT_ASSERT(e.file_ptr->is_open());
return e.file_ptr;
}
void file_pool::remove_oldest()
{
TORRENT_ASSERT(m_in_use == 1337);
file_set::iterator i = std::min_element(m_files.begin(), m_files.end()
, boost::bind(&lru_file_entry::last_use, boost::bind(&file_set::value_type::second, _1))
< boost::bind(&lru_file_entry::last_use, boost::bind(&file_set::value_type::second, _2)));
if (i == m_files.end()) return;
#if TORRENT_CLOSE_MAY_BLOCK
mutex::scoped_lock l_(m_closer_mutex);
m_queued_for_close.push_back(i->second.file_ptr);
l_.unlock();
#endif
m_files.erase(i);
}
void file_pool::release(void* st, int file_index)
{
mutex::scoped_lock l(m_mutex);
TORRENT_ASSERT(m_in_use == 1337);
file_set::iterator i = m_files.find(std::make_pair(st, file_index));
if (i == m_files.end()) return;
#if TORRENT_CLOSE_MAY_BLOCK
mutex::scoped_lock l2(m_closer_mutex);
m_queued_for_close.push_back(i->second.file_ptr);
l2.unlock();
#endif
m_files.erase(i);
}
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// closes files belonging to the specified
// storage. If 0 is passed, all files are closed
void file_pool::release(void* st)
{
mutex::scoped_lock l(m_mutex);
TORRENT_ASSERT(m_in_use == 1337);
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if (st == 0)
{
m_files.clear();
return;
}
for (file_set::iterator i = m_files.begin();
i != m_files.end();)
{
if (i->second.key == st)
m_files.erase(i++);
else
++i;
}
}
void file_pool::resize(int size)
{
TORRENT_ASSERT(size > 0);
TORRENT_ASSERT(m_in_use == 1337);
if (size == m_size) return;
mutex::scoped_lock l(m_mutex);
m_size = size;
if (int(m_files.size()) <= m_size) return;
// close the least recently used files
while (int(m_files.size()) > m_size)
remove_oldest();
}
}