add clang format config, GHA job

Author: paulgessinger

.clang-format

@@ -0,0 +1,11 @@
+---
+BasedOnStyle: Google
+IndentWidth: 4
+Language: Cpp
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+PointerAlignment: Left
+ColumnLimit: 80

.github/check_format.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# check that all code complies w/ the clang-format specification
+#
+# if all is well, returns w/o errors and does not print anything.
+# otherwise, return an error and print offending changes
+
+set -e # abort on error
+
+
+if [ $# -ne 1 ]; then
+    echo "wrong number of arguments"
+    echo ""
+    echo "usage: check_format <DIR>"
+    exit 1
+fi
+
+_binary=${CLANG_FORMAT_BINARY:-clang-format}
+
+$_binary --version
+
+cd $1
+find . \( -iname '*.cpp' -or -iname '*.hpp' -or -iname '*.ipp' -or -iname '*.cu' -or -iname '*.cuh' -or -iname '*.hip' -or -iname '*.sycl' \) \
+       -and -not -path "./*build*/*" \
+       -and -not -path "./thirdparty/*" \
+  | xargs $_binary -i -style=file
+
+
+if ! [ -z $CI ] || ! [ -z $GITHUB_ACTIONS ]; then
+  mkdir changed
+  for f in $(git diff --name-only); do
+    cp --parents $f changed
+  done
+fi
+    
+echo "clang-format done"
+    
+set +e
+git diff --exit-code --stat
+result=$?
+
+if [ "$result" -eq "128" ]; then
+    echo "Format was successfully applied"
+    echo "Could not create summary of affected files"
+    echo "Are you in a submodule?"
+
+fi
+
+exit $result

.github/workflows/checks.yml

@@ -0,0 +1,21 @@
+name: Checks
+
+on:
+  push:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    container: ghcr.io/acts-project/format10:v11
+    steps:
+      - uses: actions/checkout@v2
+      - name: Check
+        run: .github/check_format.sh .
+      - uses: actions/upload-artifact@v1
+        if: failure()
+        with:
+          name: changed
+          path: changed