fs: Add dir_size() function to obtain the total size of directory's contents

src/filesystem.cpp

@@ -914,6 +914,27 @@ int file_size(const std::string& fname)
 	return buf.st_size;
 }
 
+int dir_size(const std::string& path)
+{
+	std::vector<std::string> files, dirs;
+	get_files_in_dir(path, &files, &dirs, ENTIRE_FILE_PATH);
+
+	int res = 0;
+
+	BOOST_FOREACH(const std::string& file_path, files)
+	{
+		res += file_size(file_path);
+	}
+
+	BOOST_FOREACH(const std::string& dir_path, dirs)
+	{
+		// FIXME: this could result in infinite recursion with symlinks!!
+		res += dir_size(dir_path);
+	}
+
+	return res;
+}
+
 std::string file_name(const std::string& file)
 // Analogous to POSIX basename(3), but for C++ string-object pathnames
 {

src/filesystem.hpp

@@ -159,6 +159,9 @@ const file_tree_checksum& data_tree_checksum(bool reset = false);
 /** Returns the size of a file, or -1 if the file doesn't exist. */
 int file_size(const std::string& fname);
 
+/** Returns the sum of the sizes of the files contained in a directory. */
+int dir_size(const std::string& path);
+
 bool ends_with(const std::string& str, const std::string& suffix);
 
 /**