Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
The parser uses `rb_str_buf_new` to allocate new strings. `rb_str_buf_new` [has a minimum size of 128 and is not an embedded string](https://github.com/ruby/ruby/blob/9949407fd90c1c5bfe332141c75db995a9b867aa/string.c#L1119-L1135). This causes applications that parse JS to allocate extra memory when parsing short strings. For a real-world example, we can use the mime-types gem. The mime-types gem stores all mime types inside a JSON file and parses them when you require the gem. Here is a sample program: ```ruby require 'objspace' require 'mime-types' GC.start GC.start p ObjectSpace.memsize_of_all String ``` The example program loads the mime-types gem and outputs the total space used by all strings. Here are the results of the program before and after this patch: ** Before ** ``` [aaron@TC json (memuse)]$ ruby test.rb 5497494 [aaron@TC json (memuse)]$ ``` ** After ** ``` [aaron@TC json (memuse)]$ ruby -I lib:ext test.rb 3335862 [aaron@TC json (memuse)]$ ``` This change results in a ~40% reduction of memory use for strings in the mime-types gem. Thanks @matthewd for finding the problem, and @nobu for the patch!
- Loading branch information