RFC69: C++ code formatting - config, scripts and workflows

scripts/clang-format → .clang-format

@@ -50,9 +50,10 @@ PenaltyBreakString: 1000
 PenaltyExcessCharacter: 1000000
 PenaltyReturnTypeOnItsOwnLine: 60
 PointerAlignment: Right
+SortIncludes: false
 SpaceAfterCStyleCast: false
 SpaceBeforeAssignmentOperators: true
-SpaceBeforeParens: Never
+SpaceBeforeParens: ControlStatements
 SpaceInEmptyParentheses: false
 SpacesBeforeTrailingComments: 2
 SpacesInAngles:  false
@@ -63,5 +64,7 @@ SpacesInSquareBrackets: false
 Standard:        Cpp11
 TabWidth:        4
 UseTab:          Never
-...
 
+---
+Language: Json
+BasedOnStyle: llvm

.github/workflows/clang-format-check.yml

@@ -0,0 +1,30 @@
+
+name: clang-format Check
+
+on: [push, pull_request]
+
+jobs:
+
+  formatting-check:
+
+    name: Formatting Check
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout GDAL
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 100
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.7
+
+      - name: Install Run clang-format style check for C/C++ programs.
+        run: pip install clang-format==15.0.4
+
+      - name: Check new code with clang-format
+        run: ./scripts/clang-format.sh
+
+

.pre-commit-config.yaml

@@ -27,3 +27,25 @@ repos:
                 examples/|
                 autotest/ogr/data/
               )
+    -   repo: https://github.com/pre-commit/mirrors-clang-format
+        rev: 'v15.0.4'
+        hooks:
+        -   id: clang-format
+            exclude: >
+              (?x)^(
+                swig/|
+                third_party/|
+                autotest/ogr/data/|
+                alg/internal_libqhull/|
+                frmts/gtiff/libtiff/|
+                frmts/gtiff/libgeotiff/|
+                frmts/jpeg/libjpeg/|
+                frmts/jpeg/libjpeg12/|
+                frmts/png/libpng/|
+                frmts/gif/giflib/|
+                frmts/zlib/|
+                frmts/pcidsk/sdk|
+                frmts/grib/degrib/degrib|
+                frmts/grib/degrib/g2clib|
+                ogr/ogrsf_frmts/geojson/libjson/
+              )

scripts/clang-format.sh

@@ -0,0 +1,65 @@
+#!/bin/sh
+set -eu
+
+if ! (clang-format --version >/dev/null); then
+  echo "clang-format not available. Install it with 'pre-commit'"
+  exit 1
+fi
+
+# GNU prefix command for mac os support (gsed)
+GP=
+# shellcheck disable=SC2039
+case "${OSTYPE:-}" in
+  darwin*)
+    GP=g
+    ;;
+esac
+
+# determine changed files
+FILES=$(git diff --diff-filter=AM --name-only HEAD~1| tr '\n' ' ' | sort -u)
+
+if [ -z "$FILES" ]; then
+  echo "nothing was modified"
+  exit 0
+fi
+
+STYLEDIFF=/tmp/clang-format.diff
+true > $STYLEDIFF
+
+for f in $FILES; do
+	if ! [ -f "$f" ]; then
+		echo "$f was removed." >>/tmp/ctest-important.log
+		continue
+	fi
+
+	# echo "Checking $f"
+	case "$f" in
+	*.cpp|*.c|*.h|*.cxx|*.hxx|*.c++|*.h++|*.cc|*.hh|*.C|*.H)
+		;;
+
+	*)
+		continue
+		;;
+	esac
+
+	m="$f.prepare"
+	cp "$f" "$m"
+	clang-format -i "$f"
+	if diff -u "$m" "$f" >>$STYLEDIFF; then
+		rm "$m"
+	else
+		echo "File $f is not styled properly."
+	fi
+done
+
+if [ -s "$STYLEDIFF" ]; then
+	echo
+	echo "Required code formatting updates:"
+	cat "$STYLEDIFF"
+
+	cat <<EOF
+Tips to prevent and resolve:
+* Run pre-commit to install clang-format for C++ code style
+EOF
+	exit 1
+fi