Grant Proposal: Implement Perl Binding for libuv

UV

• Name:

  Paul Evans

• Amount Requested:

  USD 3,698 (Converted at time of submission from GBP)

Synopsis

Implement a Perl binding for libuv, wrapping as many of the features and types as is practical and useful for Perl 5.

Benefits to the Perl Community

The libuv library provides a multi-platform event system, and is the basis for the nodejs JavaScript and moarvm Perl 6 runtimes and the neovim text editor, to give a few examples. It is widely used as a support library by a wide variety of software and has language bindings for C#, Python 3, C++ and Lua, as well as being accessible directly via NodeJS. Adding Perl 5 to this list will allow programmers familiar with it from other langauges to make use of it from Perl 5, and will bring to Perl 5 several useful abilities the library provides that most other event systems do not.

Deliverables

The primary deliverable would be a newer version of UV whose internal implementation has been reworked to have a better architecture to more easily maintain going forward and that eliminates the current leaks and hangs on polling.

A number of known bugs already exist and a few are collected on GitHub (at https://github.com/genio/p5-UV/issues). Other issues are collected on the Mojo::Reactor::UV module, which could be considered to be a real-world example usage: https://github.com/Grinnz/Mojo-Reactor-UV/issues.

In addition to that first release, subsequent releases would be made to add the missing features of the current implementation, namely requests: http://docs.libuv.org/en/v1.x/request.html. The currently missing handle objects would also be added.

Upon fully implementing the features of the library, a secondary deliverable will be a set of blog posts and presentations to educate potential users, and to demonstrate its use. Some blog posts may draw contrasts and similarities to other languages, helping to further emphasize the impact of this cross-platform library in all of these languages. In particular, parallels to Perl 6, Python 3, and NodeJS may be useful as those languages are ones that potential users may also be familiar with.

Project Details

While a binding already exists in the namespace UV, it suffers many shortcomings and bugs. The current maintainer is willing to work with me on rebuilding it in a better form, now that the existing structure is more understood. We should be able to preserve much of the existing documentation and unit tests, which will be helpful in getting a good start.

Inch-stones

The heart of UV, UV::Loop has been implemented, but is in need of a rewrite to fix it and clear up the bugs.

Once this is done, the various handle types need to be wrapped; around 15 different types in total. Writing a good implementation for any one of them is likely to take an amount of time and research, but from that point the remaining ones should follow along somewhat easier, as they all follow a similar pattern.

Project Schedule

There are two main phases to this project.

The first phase will involve rebuilding the XS implementation of the current portion of libuv which has already been attempted, sufficient to cover the existing unit tests for the loop itself and the currently-implemented handle types (check, handle, idle, poll, prepare and timer). As mentioned, it is likely that the existing documentation and unit tests of these can be retained and provided with a better code implementation. The tests will help illustrate that the implementation has been completed.

This first ph