diff --git a/docs/manual.rst b/docs/manual.rst index 9a5bf731d..c761d4cf7 100644 --- a/docs/manual.rst +++ b/docs/manual.rst @@ -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 --------------- diff --git a/include/libtorrent/storage.hpp b/include/libtorrent/storage.hpp index 4a0395274..c680e561b 100755 --- a/include/libtorrent/storage.hpp +++ b/include/libtorrent/storage.hpp @@ -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: diff --git a/src/storage.cpp b/src/storage.cpp index 5f5ad023c..54d47c3e6 100755 --- a/src/storage.cpp +++ b/src/storage.cpp @@ -84,6 +84,10 @@ POSSIBILITY OF SUCH DAMAGE. #include #endif +#if defined(__linux__) +#include +#endif + #if defined(_WIN32) && defined(UNICODE) #include @@ -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(