More On Doxygen From XCode
January 13, 2010

I posted last week about running Doxygen from XCode using a custom build step.

I originally found a nice article on the Apple website here which describes how to do this, but it needed a little bit of tweaking, and wasn’t great, so I’ve improved the process a little bit.

First of all, I moved the bulk of the work into a script file, so that I can reuse it in multiple projects. This seems more sensible than cutting & pasting into every project. DRY principle!

I also decided to use a standard layout, relative to the project file, which meant that I could cut down on the number of variables that needed defining per-project.

My custom build step now just has to define a couple of variables and call on to the script.

You can find my version of the script here:

http://github.com/samdeane/code-snippets/blob/master/scripts/build-doxygen.sh

It could be cleaned up a lot more - it’s basically copied from Apple’s script then hacked a bit - I didn’t write it with public review in mind! One thing I fixed in the script was support for projects that have a space in their name or the name of a containing folder. Bloody unix programmers!

Second, I was annoyed by the output of the script, so I piped it into a file.

Finally, I was also annoyed at having to wait for the script to complete. Rebuilding the documentation each time is useful, but it’s not like you actually want to go and use it immediately.

So, I tweaked the build step to run it in the background.

Now my build step looks like this:

${WORKROOT}/scripts/xcode/build-doxygen.sh > “$TEMP_DIR/doxygen.output.log” 2> “$TEMP_DIR/doxygen.log” &

$WORKROOT is a variable that points to the root of my development folder - you can just replace it with the path to the build-doxygen.sh script file.

The script file itself relies on one extra variable - $DOXYGEN_ID - which I define in the project settings. It uses this to name the documentation bundle - so you should set it to something appropriate for the product - like com.yourcompany.yourproduct.

If you want to see the output of the script, you can add a second line:

open “$TEMP_DIR/doxygen.output.log”

This will launch Console and open the log file. Console is smart enough to update as the log file gets filled in, so it works even though the script may not have finished running by the time you open the log.

Update: one more thing…

By default XCode runs the build step every time. You can tell it to be a bit smarter by telling it what the input files and output files are for the step; it will then dependency check them.

I set the inputs to:

And the output to:

Now, if you do something that doesn’t change the source code, the documentation shouldn’t rebuild.