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factored out the test for sparse files support

This commit is contained in:
Arvid Norberg 2007-04-18 00:36:09 +00:00
parent e49c49c892
commit af779b6349
3 changed files with 103 additions and 56 deletions
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20
docs/manual.rst
View File

@ -2521,6 +2521,20 @@ If ``bdecode()`` encounters invalid encoded data in the range given to it
it will throw invalid_encoding_.
supports_sparse_files()
-----------------------
::
bool supports_sparse_files(boost::filesystem::path const&);
The path is expected to be the path to the directory where you will want to
store sparse files. The return value is true if the file system supports
sparse files or if it supports automatic zero filling of files. The main
characteristics that is tested by this function is not the storage aspects
of sparse files, but rather the support for seeking passed end of file and
write data there, with expected behavior.
alerts
======
@ -3257,6 +3271,12 @@ The allocation mode is selected when a torrent is started. It is passed as a boo
argument to ``session::add_torrent()`` (see `add_torrent()`_). These two modes have
different drawbacks and benefits.
The decision to use full allocation or compact allocation typically depends on whether
any files are filtered and if the filesystem supports sparse files.
To know if the filesystem supports sparse files (and to know if libtorrent believes the
filesystem supports sparse files), see `supports_sparse_files()`_.
full allocation
---------------

4
include/libtorrent/storage.hpp
View File

@ -113,6 +113,10 @@ namespace libtorrent
TORRENT_EXPORT storage_interface* default_storage_constructor(torrent_info const& ti
, boost::filesystem::path const& path, file_pool& fp);
// returns true if the filesystem the path relies on supports
// sparse files or automatic zero filling of files.
TORRENT_EXPORT bool supports_sparse_files(boost::filesystem::path const& p);
class TORRENT_EXPORT piece_manager : boost::noncopyable
{
public:

135
src/storage.cpp
View File

@ -84,6 +84,10 @@ POSSIBILITY OF SUCH DAMAGE.
#include <sys/mount.h>
#endif
#if defined(__linux__)
#include <sys/statfs.h>
#endif
#if defined(_WIN32) && defined(UNICODE)
#include <windows.h>
@ -767,6 +771,80 @@ namespace libtorrent
return new storage(ti, path, fp);
}
bool supports_sparse_files(path const& p)
{
assert(p.is_complete());
#if defined(WIN32)
// assume windows API is available
DWORD max_component_len = 0;
DWORD volume_flags = 0;
std::string root_device = m_save_path.root_name() + "\\";
bool ret = ::GetVolumeInformation(root_device.c_str(), 0
, 0, 0, &max_component_len, &volume_flags, 0, 0);
if (!ret) return false;
if (volume_flags & FILE_SUPPORTS_SPARSE_FILES)
return true;
#endif
#if defined(__APPLE__)
// find the last existing directory of the save path
path query_path = p;
while (!query_path.empty() && !exists(query_path))
query_path = query_path.branch_path();
struct statfs fsinfo;
int ret = statfs(query_path.native_directory_string().c_str(), &fsinfo);
if (ret != 0) return false;
attrlist request;
request.bitmapcount = ATTR_BIT_MAP_COUNT;
request.reserved = 0;
request.commonattr = 0;
request.volattr = ATTR_VOL_CAPABILITIES;
request.dirattr = 0;
request.fileattr = 0;
request.forkattr = 0;
struct vol_capabilities_attr_buf
{
unsigned long length;
vol_capabilities_attr_t info;
} vol_cap;
ret = getattrlist(fsinfo.f_mntonname, &request, &vol_cap
, sizeof(vol_cap), 0);
if (ret != 0) return false;
if (vol_cap.info.capabilities[VOL_CAPABILITIES_FORMAT]
& (VOL_CAP_FMT_SPARSE_FILES | VOL_CAP_FMT_ZERO_RUNS))
{
return true;
}
#endif
#if defined(__linux__)
struct statfs buf;
if (statfs(p.native_directory_string().c_str(), &buf) != 0);
return false;
switch (buf.f_type)
{
case 0x5346544e: // NTFS
case 0xEF51: // EXT2 OLD
case 0xEF53: // EXT2 and EXT3
case 0x00011954: // UFS
case 0x52654973: // ReiserFS
case 0x58465342: // XFS
return true;
}
#endif
// TODO: POSIX implementation
return false;
}
// -- piece_manager -----------------------------------------------------
class piece_manager::impl
@ -938,62 +1016,7 @@ namespace libtorrent
, m_save_path(complete(save_path))
, m_allocating(false)
{
assert(m_save_path.is_complete());
// try to figure out if the filesystem supports sparse files
#if defined(WIN32)
// assume windows API is available
DWORD max_component_len = 0;
DWORD volume_flags = 0;
std::string root_device = m_save_path.root_name() + "\\";
bool ret = ::GetVolumeInformation(root_device.c_str(), 0
, 0, 0, &max_component_len, &volume_flags, 0, 0);
if (ret)
{
if (volume_flags & FILE_SUPPORTS_SPARSE_FILES)
m_fill_mode = false;
}
#elif defined(__APPLE__)
// find the last existing directory of the save path
path query_path = m_save_path;
while (!query_path.empty() && !exists(query_path))
query_path = query_path.branch_path();
struct statfs fsinfo;
int ret = statfs(query_path.native_directory_string().c_str(), &fsinfo);
if (ret != 0) return;
attrlist request;
request.bitmapcount = ATTR_BIT_MAP_COUNT;
request.reserved = 0;
request.commonattr = 0;
request.volattr = ATTR_VOL_CAPABILITIES;
request.dirattr = 0;
request.fileattr = 0;
request.forkattr = 0;
struct vol_capabilities_attr_buf
{
unsigned long length;
vol_capabilities_attr_t info;
} vol_cap;
ret = getattrlist(fsinfo.f_mntonname, &request, &vol_cap
, sizeof(vol_cap), 0);
if (ret == 0 && vol_cap.info.capabilities[VOL_CAPABILITIES_FORMAT]
& (VOL_CAP_FMT_SPARSE_FILES | VOL_CAP_FMT_ZERO_RUNS))
{
m_fill_mode = false;
}
// TODO: None of those flags are set for HFS+, which
// is supposed to support zero filling
m_fill_mode = false;
#else
//TODO: posix implementation
m_fill_mode = false;
#endif
m_fill_mode = !supports_sparse_files(save_path);
}
piece_manager::piece_manager(