Setup pre-commit and include code formatting scripts

This patch
    - includes our code formatting scripts used in our precommit pipeline
    - sets up pre-commit framework to help contributors validate their patches

This has several benefits:
    - our repository becomes more inclusive to external contributions
    - we can use several hooks available online efficiently, w/o implementing our own
    - it speeds up our development flow

and, it is completely optional.

The pre-commit configuration includes running the following:
    - our code formatting scripts
    - CMake and Bazel build file generation scripts
    - hooks that check trailing whitespace, end of files, committed large files etc.

The number of checks can easily be extended using pre-commit framework.

Change-Id: I06bf1259715579d321f89820726a8301504c36d9
Signed-off-by: Gunes Bayir <gunes.bayir@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/10064
Reviewed-by: Jakub Sujak <jakub.sujak@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/docs/contributor_guide/contribution_guidelines.dox b/docs/contributor_guide/contribution_guidelines.dox
index 30ee41af0f..cbaa502635 100644
--- a/docs/contributor_guide/contribution_guidelines.dox
+++ b/docs/contributor_guide/contribution_guidelines.dox
@@ -335,6 +335,26 @@ void foo(const Goo &g);             // OK
 
 astyle (http://astyle.sourceforge.net/) and clang-format (https://clang.llvm.org/docs/ClangFormat.html) can check and help you apply some of these rules.
 
+We have also provided the python scripts we use in our precommit pipeline inside scripts directory.
+    - format_code.py: checks Android.bp, bad style, end of file, formats doxygen, runs astyle and clang-format (assuming necessary binaries are in the path). Example invocations:
+@code{.sh}
+        python format_code.py
+        python format_code.py --error-on-diff
+        python format_code.py --files=git-diff (Default behavior in pre-commit configuration, where it checks the staged files)
+@endcode
+    - generate_build_files.py: generates build files required for CMake and Bazel builds. Example invocations:
+@code{.sh}
+        python generate_build_files.py --cmake
+        python generate_build_files.py --bazel
+@endcode
+
+Another way of running the checks is using `pre-commit` (https://pre-commit.com/) framework, which has also nice features like checking trailing spaces, and large committed files etc.
+`pre-commit` can be installed via `pip`. After installing, run the following command in the root directory of the repository:
+
+	pre-commit install
+
+This will create the hooks that perform the formatting checks mentioned above and will automatically run just before committing to flag issues.
+
 @subsection S5_1_3_library_size_guidelines Library size: best practices and guidelines
 
 @subsubsection S5_1_3_1_template_suggestions Template suggestions