Add pre-commit hook for clang format

.clang-format

@@ -0,0 +1,28 @@
+# Format Style Options - Created with Clang Power Tools
+---
+BasedOnStyle: Mozilla
+AlignAfterOpenBracket: DontAlign
+AlignConsecutiveMacros: AcrossEmptyLines
+AlignConsecutiveAssignments: Consecutive
+AlignConsecutiveDeclarations: Consecutive
+AlignEscapedNewlines: Left
+AllowAllArgumentsOnNextLine: false
+AllowAllParametersOfDeclarationOnNextLine: true
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+BinPackArguments: true
+BinPackParameters: true
+BreakBeforeBinaryOperators: All
+BreakBeforeBraces: Attach
+BreakStringLiterals: false
+ColumnLimit: 150
+DerivePointerAlignment: true
+ExperimentalAutoDetectBinPacking: true
+IndentCaseLabels: false
+IndentCaseBlocks: true
+MaxEmptyLinesToKeep: 2
+SpaceAfterCStyleCast: true
+SpaceBeforeParens: Always
+SpaceAroundPointerQualifiers: Before
+UseTab: Always
+...

.pre-commit-config.yaml

@@ -10,6 +10,8 @@ repos:
     -   id: check-executables-have-shebangs
     -   id: forbid-new-submodules
     -   id: check-yaml
+    -   id: check-yaml
+        exclude: '.clang-format'
     -   id: check-json
     -   id: pretty-format-json
         args: ['--no-sort-keys']
@@ -37,3 +39,10 @@ repos:
     hooks:
     - id: markdownlint
       args: ['--fix']
+-   repo: local
+    hooks:
+    - id: clang-format
+      name: clang-format
+      language: script
+      entry: ./contrib/reformat-code.py
+      types: [c]

contrib/reformat-code.py

@@ -0,0 +1,90 @@
+#!/usr/bin/python3
+#
+# Copyright (C) 2017 Dell Inc.
+#
+# SPDX-License-Identifier: LGPL-2.1+
+#
+
+import os
+import sys
+import subprocess
+import argparse
+
+CLANG_DIFF_FORMATTERS = [
+    "clang-format-diff-11",
+    "clang-format-diff-13",
+    "clang-format-diff",
+]
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="Reformat C code to match project style",
+        epilog="Call with no argument to reformat uncommitted code.",
+    )
+    parser.add_argument(
+        "commit", nargs="*", default="", help="Reformat all changes since this commit"
+    )
+    parser.add_argument(
+        "--debug", action="store_true", help="Display all launched commands"
+    )
+    return parser.parse_args()
+
+
+def select_clang_version(formatters):
+    for formatter in formatters:
+        try:
+            ret = subprocess.check_call(
+                [formatter, "--help"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
+            )
+            if ret == 0:
+                return formatter
+        except FileNotFoundError:
+            continue
+    print("No clang formatter installed")
+    sys.exit(1)
+
+
+## Entry Point ##
+if __name__ == "__main__":
+    args = parse_args()
+    base = os.getenv("GITHUB_BASE_REF")
+    if base:
+        base = f"origin/{base}"
+    else:
+        if args.commit:
+            base = args.commit[0]
+        else:
+            base = "HEAD"
+    cmd = ["git", "describe", base]
+    if args.debug:
+        print(cmd)
+    ret = subprocess.run(cmd, capture_output=True)
+    if ret.returncode:
+        if args.debug:
+            print(ret.stderr)
+        base = "HEAD"
+    print(f"Reformatting code against {base}")
+    formatter = select_clang_version(CLANG_DIFF_FORMATTERS)
+    cmd = ["git", "diff", "-U0", base]
+    if args.debug:
+        print(cmd)
+    ret = subprocess.run(cmd, capture_output=True, text=True)
+    if ret.returncode:
+        print(f"Failed to run {cmd}\n{ret.stderr.strip()}")
+        sys.exit(1)
+    cmd = [formatter, "-regex", "^.*\\.(c|h|proto)$", "-p1"]
+    if args.debug:
+        print(cmd)
+    ret = subprocess.run(cmd, input=ret.stdout, capture_output=True, text=True)
+    if ret.returncode:
+        print(f"Failed to run {cmd}\n{ret.stderr.strip()}")
+        sys.exit(1)
+    cmd = ["patch", "-p0"]
+    if args.debug:
+        print(cmd)
+    ret = subprocess.run(cmd, input=ret.stdout, capture_output=True, text=True)
+    if ret.returncode:
+        print(f"Failed to run {cmd}\n{ret.stderr.strip()}")
+        sys.exit(1)
+    sys.exit(0)