ALICE O2 Coding Guidelines

Coding guidelines for the ALICE O2 project.

Documents

• Coding guidelines
• Naming and formatting conventions
• Comments guidelines

Formatting tool

The ALICE O2 projects use clang-format to push for a common code formatting. The rules are defined in the clang-format configuration file in this repository (which is propagated to other AliceO2Group repositories). With an adiabatic approach, all changes have to follow the formatting rules. A script, described below, can be used to integrate the formatting into git and suggest formatting only for changed lines.

Install clang-format and git integration

Note : The installation of clang using aliBuild is not necessary on Mac.

1. Build clang (to be done once)

aliBuild build --defaults o2 Clang

2. Load clang and clang-format

alienv load Clang/latest

3. Install git-clang-format

cd $HOME
mkdir -p bin
cd bin
wget llvm.org/svn/llvm-project/cfe/trunk/tools/clang-format/git-clang-format
chmod u+x git-clang-format

Check files' formatting

Show correctly formatted version of a file :

clang-format -style=file SOURCEFILE

Directly apply the style to a file :

clang-format -style=file -i SOURCEFILE

Apply the style to all the source and header files in a directory (recursive) :

find . -iname "*.h" -o -iname "*.cpp" | xargs clang-format -style=file -i 

Display what needs to be fixed in a file :

clang-format -style=file <SOURCEFILE> | diff <SOURCEFILE> -

Check commits' formatting

git clang-format invokes clang-format on the changes in current files or a specific commit. E.g. for the last commit

git clang-format HEAD~1

Or for all commits done with respect to the remote branch state

git clang-format origin/dev

Using an IDE

A number of config files are available here for various IDEs.

Configuration files for editors

CLion

1. Download,
2. Go to File -> Import Settings.

FAQ

• Q I strongly disagree with rule X !
• A Feel free to contact the WP3 ([email protected]) to share your concern(s). Rules have already been amended, abandoned or added based on the users feedback. However, please comply with the rules until a change is agreed by CWG11.