Last.fm – the Blog

Welcome to the second part of our Open Source series. Today we’re releasing moost, a C++ library with all the nice little tools and utilities our MIR team has developed over the past five years. If you’re a C++ developer yourself, you might notice that moost sounds quite similar to boost, and that’s on purpose. moost is the MIR team’s boost, there is hardly a project in our codebase that doesn’t depend on one or more parts of moost.

There are a lot of different things in moost. Some are really simple, yet very helpful in day-to-day work, like the which template that allows you to use pairs (and containers storing pairs) more easily with standard algorithms; or stringify, a function template that turns complex objects into strings. Other parts are slightly more sophisticated: for example, moost contains the framework that is shared by all our backend services, and that allows you to write a daemonisable service with logging, a set of standard options and even a service shell that multiple users can connect to when the service is running, all in a few lines of code.

As our backend services are inherently multi-threaded, there’s also a bit of threading support in moost. For example, the safe_shared_ptr template is immensely useful for resources that are shared between threads and need to be updated atomically.

If you’re working with large, static datasets, you’ll probably find the memory mapped dataset classes interesting. They allow you to build large datasets (like gigabytes of data) of vectors, multimaps or dense hash maps that can be simply mapped into memory — and thus shared between different processes — and accessed very much like a constant standard container.

moost also contains an abstraction for loading shared objects and instantiating objects defined inside these shared objects. It will take care of all the magic involved to avoid resource leaks.

There are more bits and bobs in there, like a simple client for the STOMP protocol, hashing and message digest functions, wrappers for key-value stores, template metaprogramming helpers and even a complete logging framework. So check it out, play with it and if you’ve got some nice tool to add, please contribute!

There’ll be more code coming up later this week that makes use of moost, so if you’re looking for some hands-on examples, stay tuned!

To be continued…