This project was originally written in C, in the Android platform style. It has been substantially re-written in C++, in the Google C++ style.
This style is summarized here.
When in doubt, clang-format -style=google is a good reference.
This codebase has both integration and unittests, all of which are expected to consistently pass against a device/emulator:
$ mmma system/tools/aidl && \
out/host/linux-x86/bin/aidl_unittests && \
adb remount && adb sync && \
adb install -r `find out/ -name aidl_test_services.apk` && \
(pushd system/tools/aidl/ && tests/integration-test.py) && \
echo "All tests pass"