Book Information: added file size (#3380)

frontend/apps/filemanager/filemanagerbookinfo.lua

@@ -51,8 +51,18 @@ function BookInfo:show(file, book_props)
 
     local directory, filename = util.splitFilePathName(file)
     local filename_without_suffix, filetype = util.splitFileNameSuffix(filename) -- luacheck: no unused
+    local file_size = lfs.attributes(file, "size") or 0
+    local size
+    if file_size > 1024*1024 then
+        size = string.format("%4.1f MB", file_size/1024/1024)
+    elseif file_size > 1024 then
+        size = string.format("%4.1f KB", file_size/1024)
+    else
+        size = string.format("%d B", file_size)
+    end
     table.insert(kv_pairs, { _("Filename:"), filename })
     table.insert(kv_pairs, { _("Format:"), filetype:upper() })
+    table.insert(kv_pairs, { _("Size:"), size })
     table.insert(kv_pairs, { _("Directory:"), filemanagerutil.abbreviate(directory) })
     table.insert(kv_pairs, "----")