sparse files fixes. now sets the size of the files in case sparse files are supported

include/libtorrent/file.hpp

@@ -110,6 +110,7 @@ namespace libtorrent
 
 		void open(boost::filesystem::path const& p, open_mode m);
 		void close();
+		void set_size(size_type size);
 
 		size_type write(const char*, size_type num_bytes);
 		size_type read(char*, size_type num_bytes);

include/libtorrent/storage.hpp

@@ -89,6 +89,10 @@ namespace libtorrent
 
 	struct TORRENT_EXPORT storage_interface
 	{
+		// create directories and set file sizes
+		// (if sparse files are supported)
+		virtual void initialize() = 0;
+
 		// may throw file_error if storage for slot does not exist
 		virtual size_type read(char* buf, int slot, int offset, int size) = 0;
 

src/file.cpp

@@ -245,6 +245,17 @@ namespace libtorrent
 			return ret;
 		}
 
+		void set_size(size_type s)
+		{
+			size_type pos = tell();
+			seek(1, 0);
+			char dummy = 0;
+			read(&dummy, 1);
+			seek(1, 0);
+			write(&dummy, 1);
+			seek(pos, 1);
+		}
+
 		size_type seek(size_type offset, int m)
 		{
 			assert(m_open_mode);
@@ -318,6 +329,11 @@ namespace libtorrent
 		return m_impl->read(buf, num_bytes);
 	}
 
+	void file::set_size(size_type s)
+	{
+		m_impl->set_size(s);
+	}
+
 	size_type file::seek(size_type pos, file::seek_mode m)
 	{
 		return m_impl->seek(pos, m.m_val);

src/file_win.cpp

@@ -238,6 +238,16 @@ namespace libtorrent
 			return bytes_read;
 		}
 
+		void set_size(size_type s)
+		{
+			size_type pos = tell();
+			seek(s, seek_begin);
+			if (FALSE == ::SetEndOfFile(m_file_handle))
+				throw_exception("file::set_size");
+
+			seek(pos, seek_begin);
+		}
+
 		size_type seek(size_type pos, seek_mode from_where)
 		{
 			assert(pos >= 0 || from_where != seek_begin);
@@ -339,6 +349,11 @@ namespace libtorrent
 		return m_impl->read(buffer, num_bytes);
 	}
 
+	void file::set_size(size_type s)
+	{
+		m_impl->set_size(s);
+	}
+
 	size_type file::seek(size_type pos, seek_mode m)
 	{
 		return m_impl->seek(pos,impl::seek_mode(m.m_val));

src/storage.cpp

@@ -372,6 +372,7 @@ namespace libtorrent
 
 		void release_files();
 
+		void initialize();
 		bool move_storage(path save_path);
 		size_type read(char* buf, int slot, int offset, int size);
 		void write(const char* buf, int slot, int offset, int size);
@@ -391,6 +392,45 @@ namespace libtorrent
 		file_pool& m_files;
 	};
 
+	void storage::initialize()
+	{
+		// first, create all missing directories
+		bool sparse = supports_sparse_files(m_save_path);
+		path last_path;
+		for (torrent_info::file_iterator file_iter = m_info.begin_files(),
+			end_iter = m_info.end_files(); file_iter != end_iter; ++file_iter)
+		{
+			path dir = (m_save_path / file_iter->path).branch_path();
+
+			if (dir != last_path)
+			{
+				last_path = dir;
+
+#if defined(_WIN32) && defined(UNICODE) && BOOST_VERSION < 13400
+				if (!exists_win(last_path))
+					create_directories_win(last_path);
+#else
+				if (!exists(last_path))
+					create_directories(last_path);
+#endif
+			}
+
+			// if the file is empty, just create it. But also make sure
+			// the directory exits.
+			if (file_iter->size == 0)
+			{
+				file(m_save_path / file_iter->path, file::out);
+				continue;
+			}
+
+			if (sparse)
+			{
+				m_files.open_file(this, m_save_path / file_iter->path, file::out)
+					->set_size(file_iter->size);
+			}
+		}
+	}
+
 	void storage::release_files()
 	{
 		m_files.release(this);
@@ -830,6 +870,8 @@ namespace libtorrent
 		{
 			return true;
 		}
+
+		return true;
 #endif
 
 #if defined(__linux__)
@@ -1522,33 +1564,8 @@ namespace libtorrent
 
 		if (m_state == state_create_files)
 		{
-			// first, create all missing directories
-			path last_path;
-			for (torrent_info::file_iterator file_iter = m_info.begin_files(),
-				end_iter = m_info.end_files();  file_iter != end_iter; ++file_iter)
-			{
-				path dir = (m_save_path / file_iter->path).branch_path();
+			m_storage->initialize();
 
-				// if the file is empty, just create it. But also make sure
-				// the directory exits.
-				if (dir == last_path
-					&& file_iter->size == 0)
-					file(m_save_path / file_iter->path, file::out);
-
-				if (dir == last_path) continue;
-				last_path = dir;
-
-#if defined(_WIN32) && defined(UNICODE) && BOOST_VERSION < 13400
-				if (!exists_win(last_path))
-					create_directories_win(last_path);
-#else
-				if (!exists(last_path))
-					create_directories(last_path);
-#endif
-
-				if (file_iter->size == 0)
-					file(m_save_path / file_iter->path, file::out);
-			}
 			m_current_slot = 0;
 			m_state = state_full_check;
 			m_piece_data.resize(int(m_info.piece_length()));