Pre-commit hook for C/C++ code format enforcement using clang-format

pre-commit.sh

#!/bin/bash

# Print an introduction line in cyan
printf "\033[0;36mPre-commit hook is linting your changes for C/CPP code...\033[0m \n"

# Grab feed of staged cppfiles
cppfiles=$(git diff --name-only --cached --diff-filter=ACMRT | \
    grep ".*\.\(c\|cc\|cpp\|h\|hh\|hpp\)$" )
numfiles=$( printf '%s' "$cppfiles" | grep -c '^' )

exitstatus=0

if [ $numfiles -eq 0 ]
then
    printf "\033[0;35mNo C/CPP files staged. Nothing to check.\033[0m\n"
    exit $exitstatus
fi


# Iterate over the filenames to discover the longest
longest=0
for i in $cppfiles
do
    if [ ${#i} -gt $longest ]
    then
        longest=${#i}
    fi
done

# Iterate over the staged filenames
for i in $cppfiles
do
    # Print file name eg: "Checking: text.txt"
    printf "\033[0;35mChecking:\033[0m %s " "$i"

  # Print some padding spaces so the failed/success statuses line up
  padding=$(expr $longest - ${#i})
  for ((n=0;n<$padding;n++))
  do
      printf " "
  done

  git clang-format --diffstat $i | grep "file.*changed" >/dev/null
  if [ $? -ne 1 ]; then
      printf "\033[0;31m[FAILED]\n"
      exitstatus=1
  else
      printf "\033[0;32m[PASSED]\n"
  fi

  # Reset print color back to default for the next iteration
  printf "\033[0m"

done

exit $exitstatus