I just used the coolest feature in a while: VS2005's Call Browser.

I'm currently working on some firmware for IP phones and adapters. The chip is the Intel 8051, as used by Centrality Communications in the PA168. It's actually quite fun, programming for an 8-bit system. Apart from writing in C (instead of such high-level things like C#), writing for embedded systems like this adds its own interesting things, like having to decide where a variable will be stored (I think there is 3 different storage locations a variable can have with the 8051). Oh yea, and having to keep things really small, and really fast.

At any rate, I am not that familiar with the entire design of the system, and I just want to focus on adding features to the IAX2 implementation (cause SIP sucks!). A large part of my work is to figure out how things work. Having the Goto Definition (F12) is great for finding specific symbols, but doesn't help with the flow. Up until now, I've been Finding in Files for a specific method, then chasing things down by recursively Finding in Files until I figured out how things are called. This happens a lot, since these devices support 5 protocols and use #ifdefs and generic calls to interface with the different protocols. Add to that 8MB of source, and it's no small task.

This morning, I remembered I had seen a “Call Browser” window in Visual Studio 2005 a while ago. Edit: Apparently this isn't a new feature and has been around since VC6 (at least). Well, it's new to ME, and it's still very cool.

Here's an example. Let's say I want to add attended transfer (where you have a call, press transfer, dial a number, talk to the new call, then hangup to connect the two). I'm looking in the source I'm familar with (the IAX protocol area), and see iax2_hangup(). That's a packet-level call, so when someone physically hangs up, that, somehow, gets called. Where? Well... right click the function, Call Browser -> Show Calls To:


Click... click... click... bingo. Now I've got a complete grasp on the call flow that would send a IAX_COMMAND_HANGUP. My old way (which makes me feel stupid now) of browsing source doesn't even come close. A lot of programming these days is managing complexity. It's all about making the best use of our limited brainspace (some more limited than others). 17 lines/1 small diagram. That's all it takes for me to see this complete flow. How much mental capacity does that require versus browsing multiple locations in 4 different source code files?