How to read source code learn how to use large system? [closed]

Answer 1

If you're familiar with the project and have some idea of what you want to contribute, then get the latest version of the code and make the change that you want to make. Don't try to digest the whole body of code at one time. Look for patterns and conventions that are being used and try to adhere to them as much as possible.

Answer 2

Learn with a purpose. I think you'll learn best if you have in mind some goal -- fix this or add that functionality. Start looking for the likely places where you will need to make your changes. Follow threads of control backwards to find out how to get to that point in the code. Also, take a "bird's eye" view of the code -- look at the layout and structure. Good code will have descriptive names that tells you want each class and method is for. See if you can recognize implementation patterns and see where/how they are used. Don't put too much stock in the documentation -- documents can be excellent, but they are often out of sync with what the code really does. Let the code itself be the best documentation.

Answer 3

I prefer to "step" through the code line by line in an IDE debugger. It is not practical to try to reach all code in a large system, but I start by debugging the start-up of the application and then move on to other areas of code that look interesting/important to the application.

Answer 4

I would run doxygen against the source code so I have a browsable, readable, class level view of the source. It is excellent for helping wade you way through a huge code base

Answer 5

If you want books that I found useful for learning how to learn from the code, I would check out Diomidis Spinellis's books Code Reading: The Open Source Perspective and Code Quality: The Open Source Perspective.

For your specific question, I would start with Code Reading. But both are good books.

Answer 6

I would suggest finding a feature that you really want to add.

I've only ever really looked through a mountain of someone else's code once, and it was made much easier because the feature I wanted to add was something I really needed. I think it's the reason most open source projects start anyway; to fill a need.

Rob