Friday, 26 February 2010

protobuf-net v2 on the iPhone

A basic iPhone application showing two fields with values in; there isn't much to see.

It might not look very impressive to you, but this is pure joy to me. It is the first evidence I’ve seen that the revised rewritten protobuf-net can work in MonoTouch for use on the iPhone – and presumably MonoDroid in the future.

A big thanks here to Christian Weyer and Andrew Rimmer who both offered some help here (since I don’t actually own a mac, an iPhone or MonoTouch!). The grab is from Andrew (he assures me it works fine on the actual device too).

This piece of work has been a slog, and I kept putting it off (because frankly, re-writing the entire stack is a huge job). The goals have not been trivial:

  • Continue to support all the existing runtime-only usage…
  • ..while also making it support fully static / AOT compatible
  • Allow it to write serialization dlls in advance (like sgen)
  • Fix the stability issues on Compact Framework (caused by overuse of generics)
  • Remove some performance bottlenecks on Compact Framework
  • Support POCO (or more accurately, work without requiring special [attributes]) so you can use it with types outside your influence, or for inheritance that isn’t known at compile-time
  • Make it work on iPhone etc
  • Make it even faster
  • Make it more extensible (for example, what if I want to write a proxy that writes a DataTable to a protobuf stream?)
  • Make it support mutable structs (yes I know that they are usually evil, but people simply keep asking for this, in particular for XNA)
  • Remove a heap of code-debt caused by an evolving project that grew without a 100% clear direction
  • Throw in some other feature-requests and bug-fixes for good measure
  • And as a side-benefit, it even compiles and runs on .NET 1.1 or via mcs on Mono (with minimal #if usage)

I should stress that it is not yet complete – but the core of the engine is there and working, demonstrating most of the key points above (albeit in a very raw state). There’s still a way to go, but it is getting there.

1 comment:

Thad said...

Mark,
Very nice work. Those of us in the community using protocol buffers (in C#, in Mono) really appreciate it.