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Git pre-commit hook that invokes clang-format to reformat C/C++/Objective-C source code.
#!/bin/bash
# git pre-commit hook that runs an clang-format stylecheck.
# Features:
# - abort commit when commit does not comply with the style guidelines
# - create a patch of the proposed style changes
# modifications for clang-format by rene.milk@wwu.de
# This file is part of a set of unofficial pre-commit hooks available
# at github.
# Link: https://github.com/githubbrowser/Pre-commit-hooks
# Contact: David Martin, david.martin.mailbox@googlemail.com
##################################################################
# SETTINGS
# set path to clang-format binary
CLANG_FORMAT="/Users/wyi/usr/bin/clang-format"
# remove any older patches from previous commits. Set to true or false.
# DELETE_OLD_PATCHES=false
DELETE_OLD_PATCHES=false
# only parse files with the extensions in FILE_EXTS. Set to true or false.
# if false every changed file in the commit will be parsed with clang-format.
# if true only files matching one of the extensions are parsed with clang-format.
# PARSE_EXTS=true
PARSE_EXTS=true
# file types to parse. Only effective when PARSE_EXTS is true.
# FILE_EXTS=".c .h .cpp .hpp"
FILE_EXTS=".c .h .cpp .hpp .cc .hh .cxx .m"
##################################################################
# There should be no need to change anything below this line.
# Reference: http://stackoverflow.com/questions/1055671/how-can-i-get-the-behavior-of-gnus-readlink-f-on-a-mac
canonicalize_filename () {
local target_file=$1
local physical_directory=""
local result=""
# Need to restore the working directory after work.
pushd `pwd` > /dev/null
cd "$(dirname "$target_file")"
target_file=`basename $target_file`
# Iterate down a (possible) chain of symlinks
while [ -L "$target_file" ]
do
target_file=$(readlink "$target_file")
cd "$(dirname "$target_file")"
target_file=$(basename "$target_file")
done
# Compute the canonicalized name by finding the physical path
# for the directory we're in and appending the target file.
physical_directory=`pwd -P`
result="$physical_directory"/"$target_file"
# restore the working directory after work.
popd > /dev/null
echo "$result"
}
# exit on error
set -e
# check whether the given file matches any of the set extensions
matches_extension() {
local filename=$(basename "$1")
local extension=".${filename##*.}"
local ext
for ext in $FILE_EXTS; do [[ "$ext" == "$extension" ]] && return 0; done
return 1
}
# necessary check for initial commit
if git rev-parse --verify HEAD >/dev/null 2>&1 ; then
against=HEAD
else
# Initial commit: diff against an empty tree object
against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi
if [ ! -x "$CLANG_FORMAT" ] ; then
printf "Error: clang-format executable not found.\n"
printf "Set the correct path in $(canonicalize_filename "$0").\n"
exit 1
fi
# create a random filename to store our generated patch
prefix="pre-commit-clang-format"
suffix="$(date +%s)"
patch="/tmp/$prefix-$suffix.patch"
# clean up any older clang-format patches
$DELETE_OLD_PATCHES && rm -f /tmp/$prefix*.patch
# create one patch containing all changes to the files
git diff-index --cached --diff-filter=ACMR --name-only $against -- | while read file;
do
# ignore file if we do check for file extensions and the file
# does not match any of the extensions specified in $FILE_EXTS
if $PARSE_EXTS && ! matches_extension "$file"; then
continue;
fi
# clang-format our sourcefile, create a patch with diff and append it to our $patch
# The sed call is necessary to transform the patch from
# --- $file timestamp
# +++ - timestamp
# to both lines working on the same file and having a a/ and b/ prefix.
# Else it can not be applied with 'git apply'.
"$CLANG_FORMAT" -style=file "$file" | \
diff -u "$file" - | \
sed -e "1s|--- |--- a/|" -e "2s|+++ -|+++ b/$file|" >> "$patch"
done
# if no patch has been generated all is ok, clean up the file stub and exit
if [ ! -s "$patch" ] ; then
printf "Files in this commit comply with the clang-format rules.\n"
rm -f "$patch"
exit 0
fi
# a patch has been created, notify the user and exit
printf "\nThe following differences were found between the code to commit "
printf "and the clang-format rules:\n\n"
cat "$patch"
printf "\nYou can apply these changes with:\n git apply $patch\n"
printf "(may need to be called from the root directory of your repository)\n"
printf "Aborting commit. Apply changes and commit again or skip checking with"
printf " --no-verify (not recommended).\n"
exit 1

Can you update lines 8 - 12 with correct links and emails. Thank you.

Pierre-Sassoulas commented Jan 30, 2018

Great code, many thanks.

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