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factor out move_storage function to storage_utils.cpp (#1571)

This commit is contained in:
Arvid Norberg 2017-01-17 08:02:44 -05:00 committed by GitHub
parent a5825c0d2e
commit ec37436d49
6 changed files with 235 additions and 209 deletions
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12
include/libtorrent/aux_/storage_utils.hpp
View File

@ -38,6 +38,7 @@ POSSIBILITY OF SUCH DAMAGE.
#include "libtorrent/config.hpp"
#include "libtorrent/span.hpp"
#include "libtorrent/units.hpp"
#include "libtorrent/storage_defs.hpp" // for status_t
#ifndef TORRENT_WINDOWS
#include <sys/uio.h> // for iovec
@ -46,6 +47,7 @@ POSSIBILITY OF SUCH DAMAGE.
namespace libtorrent
{
class file_storage;
struct part_file;
struct storage_error;
#ifdef TORRENT_WINDOWS
@ -72,7 +74,6 @@ namespace libtorrent
~fileop() {}
};
// this function is responsible for turning read and write operations in the
// torrent space (pieces) into read and write operations in the filesystem
// space (files on disk).
@ -80,6 +81,15 @@ namespace libtorrent
, span<iovec_t const> bufs, piece_index_t piece, int offset
, fileop& op, storage_error& ec);
// moves the files in file_storage f from ``save_path`` to
// ``destination_save_path`` according to the rules defined by ``flags``.
// returns the status code and the new save_path.
TORRENT_EXTRA_EXPORT std::pair<status_t, std::string>
move_storage(file_storage const& f
, std::string const& save_path
, std::string const& destination_save_path
, part_file* pf
, int const flags, storage_error& ec);
}
#endif

9
include/libtorrent/disk_interface.hpp
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@ -58,15 +58,6 @@ namespace libtorrent
struct storage_params;
class file_storage;
enum class status_t : std::uint8_t
{
// return values from check_fastresume, and move_storage
no_error,
fatal_disk_error,
need_full_check,
file_exist
};
struct storage_holder;
struct TORRENT_EXTRA_EXPORT disk_interface

21
include/libtorrent/storage.hpp
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@ -231,27 +231,6 @@ namespace libtorrent
std::unordered_set<cached_piece_entry*> m_cached_pieces;
};
// flags for async_move_storage
enum move_flags_t
{
// replace any files in the destination when copying
// or moving the storage
always_replace_files,
// if any files that we want to copy exist in the destination
// exist, fail the whole operation and don't perform
// any copy or move. There is an inherent race condition
// in this mode. The files are checked for existence before
// the operation starts. In between the check and performing
// the copy, the destination files may be created, in which
// case they are replaced.
fail_if_exist,
// if any file exist in the target, take those files instead
// of the ones we may have in the source.
dont_replace
};
// The storage interface is a pure virtual class that can be implemented to
// customize how and where data for a torrent is stored. The default storage
// implementation uses regular files in the filesystem, mapping the files in

31
include/libtorrent/storage_defs.hpp
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@ -38,7 +38,6 @@ POSSIBILITY OF SUCH DAMAGE.
#include "libtorrent/aux_/vector.hpp"
#include <functional>
#include <string>
#include <vector>
namespace libtorrent
{
@ -63,6 +62,36 @@ namespace libtorrent
storage_mode_sparse
};
enum class status_t : std::uint8_t
{
// return values from check_fastresume, and move_storage
no_error,
fatal_disk_error,
need_full_check,
file_exist
};
// flags for async_move_storage
enum move_flags_t
{
// replace any files in the destination when copying
// or moving the storage
always_replace_files,
// if any files that we want to copy exist in the destination
// exist, fail the whole operation and don't perform
// any copy or move. There is an inherent race condition
// in this mode. The files are checked for existence before
// the operation starts. In between the check and performing
// the copy, the destination files may be created, in which
// case they are replaced.
fail_if_exist,
// if any file exist in the target, take those files instead
// of the ones we may have in the source.
dont_replace
};
// see default_storage::default_storage()
struct TORRENT_EXPORT storage_params
{

180
src/storage.cpp
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@ -804,185 +804,11 @@ namespace libtorrent
status_t default_storage::move_storage(std::string const& sp, int const flags
, storage_error& ec)
{
status_t ret = status_t::no_error;
std::string const save_path = complete(sp);
// check to see if any of the files exist
file_storage const& f = files();
if (flags == fail_if_exist)
{
file_status s;
error_code err;
stat_file(save_path, &s, err);
if (err != boost::system::errc::no_such_file_or_directory)
{
// the directory exists, check all the files
for (file_index_t i(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are ignored
if (f.file_absolute_path(i)) continue;
stat_file(f.file_path(i, save_path), &s, err);
if (err != boost::system::errc::no_such_file_or_directory)
{
ec.ec = err;
ec.file(i);
ec.operation = storage_error::stat;
return status_t::file_exist;
}
}
}
}
{
file_status s;
error_code err;
stat_file(save_path, &s, err);
if (err == boost::system::errc::no_such_file_or_directory)
{
err.clear();
create_directories(save_path, err);
if (err)
{
ec.ec = err;
ec.file(file_index_t(-1));
ec.operation = storage_error::mkdir;
return status_t::fatal_disk_error;
}
}
else if (err)
{
ec.ec = err;
ec.file(file_index_t(-1));
ec.operation = storage_error::stat;
return status_t::fatal_disk_error;
}
}
m_pool.release(storage_index());
// indices of all files we ended up copying. These need to be deleted
// later
aux::vector<bool, file_index_t> copied_files(std::size_t(f.num_files()), false);
file_index_t i;
error_code e;
for (i = file_index_t(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
std::string const old_path = combine_path(m_save_path, f.file_path(i));
std::string const new_path = combine_path(save_path, f.file_path(i));
if (flags == dont_replace && exists(new_path))
{
if (ret == status_t::no_error) ret = status_t::need_full_check;
continue;
}
// TODO: ideally, if we end up copying files because of a move across
// volumes, the source should not be deleted until they've all been
// copied. That would let us rollback with higher confidence.
move_file(old_path, new_path, e);
// if the source file doesn't exist. That's not a problem
// we just ignore that file
if (e == boost::system::errc::no_such_file_or_directory)
e.clear();
else if (e
&& e != boost::system::errc::invalid_argument
&& e != boost::system::errc::permission_denied)
{
// moving the file failed
// on OSX, the error when trying to rename a file across different
// volumes is EXDEV, which will make it fall back to copying.
e.clear();
copy_file(old_path, new_path, e);
if (!e) copied_files[i] = true;
}
if (e)
{
ec.ec = e;
ec.file(i);
ec.operation = storage_error::rename;
break;
}
}
if (!e && m_part_file)
{
m_part_file->move_partfile(save_path, e);
if (e)
{
ec.ec = e;
ec.file(file_index_t(-1));
ec.operation = storage_error::partfile_move;
}
}
if (e)
{
// rollback
while (--i >= file_index_t(0))
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
// if we ended up copying the file, don't do anything during
// roll-back
if (copied_files[i]) continue;
std::string const old_path = combine_path(m_save_path, f.file_path(i));
std::string const new_path = combine_path(save_path, f.file_path(i));
// ignore errors when rolling back
error_code ignore;
move_file(new_path, old_path, ignore);
}
return status_t::fatal_disk_error;
}
std::string const old_save_path = m_save_path;
m_save_path = save_path;
std::set<std::string> subdirs;
for (i = file_index_t(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
if (has_parent_path(f.file_path(i)))
subdirs.insert(parent_path(f.file_path(i)));
// if we ended up renaming the file instead of moving it, there's no
// need to delete the source.
if (copied_files[i] == false) continue;
std::string const old_path = combine_path(old_save_path, f.file_path(i));
// we may still have some files in old old_save_path
// eg. if (flags == dont_replace && exists(new_path))
// ignore errors when removing
error_code ignore;
remove(old_path, ignore);
}
for (std::string const& s : subdirs)
{
error_code err;
std::string subdir = combine_path(old_save_path, s);
while (subdir != old_save_path && !err)
{
remove(subdir, err);
subdir = parent_path(subdir);
}
}
status_t ret;
std::tie(ret, m_save_path) = libtorrent::move_storage(files(), m_save_path, sp
, m_part_file.get(), flags, ec);
return ret;
}

191
src/storage_utils.cpp
View File

@ -34,6 +34,10 @@ POSSIBILITY OF SUCH DAMAGE.
#include "libtorrent/file_storage.hpp"
#include "libtorrent/alloca.hpp"
#include "libtorrent/file.hpp" // for count_bufs
#include "libtorrent/part_file.hpp"
#include <set>
#include <string>
namespace libtorrent
{
@ -183,5 +187,192 @@ namespace libtorrent
return size;
}
std::pair<status_t, std::string> move_storage(file_storage const& f
, std::string const& save_path
, std::string const& destination_save_path
, part_file* pf
, int const flags, storage_error& ec)
{
status_t ret = status_t::no_error;
std::string const new_save_path = complete(destination_save_path);
// check to see if any of the files exist
if (flags == fail_if_exist)
{
file_status s;
error_code err;
stat_file(new_save_path, &s, err);
if (err != boost::system::errc::no_such_file_or_directory)
{
// the directory exists, check all the files
for (file_index_t i(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are ignored
if (f.file_absolute_path(i)) continue;
stat_file(f.file_path(i, new_save_path), &s, err);
if (err != boost::system::errc::no_such_file_or_directory)
{
ec.ec = err;
ec.file(i);
ec.operation = storage_error::stat;
return { status_t::file_exist, save_path };
}
}
}
}
{
file_status s;
error_code err;
stat_file(new_save_path, &s, err);
if (err == boost::system::errc::no_such_file_or_directory)
{
err.clear();
create_directories(new_save_path, err);
if (err)
{
ec.ec = err;
ec.file(file_index_t(-1));
ec.operation = storage_error::mkdir;
return { status_t::fatal_disk_error, save_path };
}
}
else if (err)
{
ec.ec = err;
ec.file(file_index_t(-1));
ec.operation = storage_error::stat;
return { status_t::fatal_disk_error, save_path };
}
}
// indices of all files we ended up copying. These need to be deleted
// later
aux::vector<bool, file_index_t> copied_files(std::size_t(f.num_files()), false);
file_index_t i;
error_code e;
for (i = file_index_t(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
std::string const old_path = combine_path(save_path, f.file_path(i));
std::string const new_path = combine_path(new_save_path, f.file_path(i));
if (flags == dont_replace && exists(new_path))
{
if (ret == status_t::no_error) ret = status_t::need_full_check;
continue;
}
// TODO: ideally, if we end up copying files because of a move across
// volumes, the source should not be deleted until they've all been
// copied. That would let us rollback with higher confidence.
move_file(old_path, new_path, e);
// if the source file doesn't exist. That's not a problem
// we just ignore that file
if (e == boost::system::errc::no_such_file_or_directory)
e.clear();
else if (e
&& e != boost::system::errc::invalid_argument
&& e != boost::system::errc::permission_denied)
{
// moving the file failed
// on OSX, the error when trying to rename a file across different
// volumes is EXDEV, which will make it fall back to copying.
e.clear();
copy_file(old_path, new_path, e);
if (!e) copied_files[i] = true;
}
if (e)
{
ec.ec = e;
ec.file(i);
ec.operation = storage_error::rename;
break;
}
}
if (!e && pf)
{
pf->move_partfile(new_save_path, e);
if (e)
{
ec.ec = e;
ec.file(file_index_t(-1));
ec.operation = storage_error::partfile_move;
}
}
if (e)
{
// rollback
while (--i >= file_index_t(0))
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
// if we ended up copying the file, don't do anything during
// roll-back
if (copied_files[i]) continue;
std::string const old_path = combine_path(save_path, f.file_path(i));
std::string const new_path = combine_path(new_save_path, f.file_path(i));
// ignore errors when rolling back
error_code ignore;
move_file(new_path, old_path, ignore);
}
return { status_t::fatal_disk_error, save_path };
}
// TODO: 2 technically, this is where the transaction of moving the files
// is completed. This is where the new save_path should be committed. If
// there is an error in the code below, that should not prevent the new
// save path to be set. Maybe it would make sense to make the save_path
// an in-out parameter
std::set<std::string> subdirs;
for (i = file_index_t(0); i < f.end_file(); ++i)
{
// files moved out to absolute paths are not moved
if (f.file_absolute_path(i)) continue;
if (has_parent_path(f.file_path(i)))
subdirs.insert(parent_path(f.file_path(i)));
// if we ended up renaming the file instead of moving it, there's no
// need to delete the source.
if (copied_files[i] == false) continue;
std::string const old_path = combine_path(save_path, f.file_path(i));
// we may still have some files in old save_path
// eg. if (flags == dont_replace && exists(new_path))
// ignore errors when removing
error_code ignore;
remove(old_path, ignore);
}
for (std::string const& s : subdirs)
{
error_code err;
std::string subdir = combine_path(save_path, s);
while (subdir != save_path && !err)
{
remove(subdir, err);
subdir = parent_path(subdir);
}
}
return { ret, new_save_path };
}
}