add_file_borrow: use string_view instead of pointer, size parameters (#2302)

include/libtorrent/file_storage.hpp

@@ -232,16 +232,16 @@ namespace libtorrent {
 		void reserve(int num_files);
 
 		// Adds a file to the file storage. The ``add_file_borrow`` version
-		// expects that ``filename`` points to a string of ``filename_len``
-		// bytes that is the file name (without a path) of the file that's
-		// being added. This memory is *borrowed*, i.e. it is the caller's
+		// expects that ``filename`` is the file name (without a path) of
+		// the file that's being added.
+		// This memory is *borrowed*, i.e. it is the caller's
 		// responsibility to make sure it stays valid throughout the lifetime
 		// of this file_storage object or any copy of it. The same thing applies
 		// to ``filehash``, which is an optional pointer to a 20 byte binary
 		// SHA-1 hash of the file.
 		//
-		// if ``filename`` is nullptr, the filename from ``path`` is used and not
-		// borrowed. In this case ``filename_len`` is ignored.
+		// if ``filename`` is empty, the filename from ``path`` is used and not
+		// borrowed.
 		//
 		// The ``path`` argument is the full path (in the torrent file) to
 		// the file to add. Note that this is not supposed to be an absolute
@@ -268,7 +268,7 @@ namespace libtorrent {
 		// That is, the first path element of all files must be the same.
 		// This shared path element is also set to the name of the torrent. It
 		// can be changed by calling ``set_name``.
-		void add_file_borrow(char const* filename, int filename_len
+		void add_file_borrow(string_view filename
 			, std::string const& path, std::int64_t file_size
 			, file_flags_t file_flags = {}, char const* filehash = 0
 			, std::int64_t mtime = 0, string_view symlink_path = string_view());
@@ -282,6 +282,11 @@ namespace libtorrent {
 
 #ifndef TORRENT_NO_DEPRECATE
 		TORRENT_DEPRECATED
+		void add_file_borrow(char const* filename, int filename_len
+			, std::string const& path, std::int64_t file_size
+			, file_flags_t file_flags = {}, char const* filehash = 0
+			, std::int64_t mtime = 0, string_view symlink_path = string_view());
+		TORRENT_DEPRECATED
 		void add_file(file_entry const& fe, char const* filehash = nullptr);
 
 		// all wstring APIs are deprecated since 0.16.11

src/file_storage.cpp

@@ -344,6 +344,15 @@ namespace {
 
 #ifndef TORRENT_NO_DEPRECATE
 
+	void file_storage::add_file_borrow(char const* filename, int filename_len
+		, std::string const& path, std::int64_t file_size, file_flags_t file_flags
+		, char const* filehash, std::int64_t mtime, string_view symlink_path)
+	{
+		TORRENT_ASSERT(filename_len >= 0);
+		add_file_borrow({filename, std::size_t(filename_len)}, path, file_size
+			, file_flags, filehash, mtime, symlink_path);
+	}
+
 	void file_storage::add_file(file_entry const& fe, char const* filehash)
 	{
 		file_flags_t flags = {};
@@ -352,7 +361,7 @@ namespace {
 		if (fe.executable_attribute) flags |= file_storage::flag_executable;
 		if (fe.symlink_attribute) flags |= file_storage::flag_symlink;
 
-		add_file_borrow(nullptr, 0, fe.path, fe.size, flags, filehash, fe.mtime
+		add_file_borrow({}, fe.path, fe.size, flags, filehash, fe.mtime
 			, fe.symlink_path);
 	}
 
@@ -547,11 +556,11 @@ namespace {
 	void file_storage::add_file(std::string const& path, std::int64_t file_size
 		, file_flags_t const file_flags, std::time_t mtime, string_view symlink_path)
 	{
-		add_file_borrow(nullptr, 0, path, file_size, file_flags, nullptr, mtime
+		add_file_borrow({}, path, file_size, file_flags, nullptr, mtime
 			, symlink_path);
 	}
 
-	void file_storage::add_file_borrow(char const* filename, int const filename_len
+	void file_storage::add_file_borrow(string_view filename
 		, std::string const& path, std::int64_t const file_size
 		, file_flags_t const file_flags, char const* filehash
 		, std::int64_t const mtime, string_view symlink_path)
@@ -581,11 +590,11 @@ namespace {
 		// if filename is nullptr, we should copy it. If it isn't, we're borrowing
 		// it and we can save the copy by setting it after this call to
 		// update_path_index().
-		update_path_index(e, path, filename == nullptr);
+		update_path_index(e, path, filename.empty());
 
 		// filename is allowed to be nullptr, in which case we just use path
-		if (filename)
-			e.set_name(filename, true, filename_len);
+		if (!filename.empty())
+			e.set_name(filename.data(), true, int(filename.size()));
 
 		e.size = aux::numeric_cast<std::uint64_t>(file_size);
 		e.offset = aux::numeric_cast<std::uint64_t>(m_total_size);

src/torrent_info.cpp

@@ -484,7 +484,7 @@ namespace {
 			filename_len = 0;
 		}
 
-		files.add_file_borrow(filename, filename_len, path, file_size, file_flags, filehash
+		files.add_file_borrow({filename, std::size_t(filename_len)}, path, file_size, file_flags, filehash
 			, mtime, symlink_path);
 		return true;
 	}

test/test_file_storage.cpp

@@ -177,7 +177,7 @@ TORRENT_TEST(pointer_offset)
 	file_storage st;
 	char const filename[] = "test1fooba";
 
-	st.add_file_borrow(filename, 5, combine_path("test-torrent-1", "test1")
+	st.add_file_borrow({filename, 5}, combine_path("test-torrent-1", "test1")
 		, 10);
 
 	// test filename_ptr and filename_len