#!/bin/bash
#
# Hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.

# This hook:
#  * checks for whitespace errors
#  * checks for bad characters
#  * runs tests on changes that are about to be committed

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 you want to allow non-ascii filenames set this variable to true.
allownonascii=$(git config hooks.allownonascii)

# Cross platform projects tend to avoid non-ascii filenames; prevent
# them from being added to the repository. We exploit the fact that the
# printable range starts at the space character and ends with tilde.
if [ "$allownonascii" != "true" ] &&
    # Note that the use of brackets around a tr range is ok here, (it's
    # even required, for portability to Solaris 10's /usr/bin/tr), since
    # the square bracket bytes happen to fall in the designated range.
    test "$(git diff --cached --name-only --diff-filter=A -z $against |
      LC_ALL=C tr -d '[ -~]\0')"
then
    echo "Error: Attempt to add a non-ascii file name."
    echo
    echo "This can cause problems if you want to work"
    echo "with people on other platforms."
    echo
    echo "To be portable it is advisable to rename the file ..."
    echo
    echo "If you know what you are doing you can disable this"
    echo "check using:"
    echo
    echo "  git config hooks.allownonascii true"
    echo
    exit 1
fi

function pop_stashed()
{
    # pop stashed changes if working directory wasn't clean
    if [ -z "$DIRTY" ]; then
        return
    fi

    git reset --hard HEAD
    local skipped="$(git ls-files -t | grep ^S | cut -d' ' -f2-)"
    if ! git stash pop --quiet --index; then
        return 1
    fi

    while read file; do
        git update-index --skip-worktree "$file"
    done <<< "$skipped"
}

function check_odd_whitespace()
{
    # check for odd whitespace
    git diff-index --check --color $1 $against --
    local check_exit_code="$?"
    if [ "$check_exit_code" -ne "0" ]; then
        echo -e "\e[1;31m""Your changes introduce whitespace errors" "\e[7;0m"
        if [[ -z "$ALLOW_WHITESPACE_ERRORS" ]]; then
            exit $check_exit_code
        fi
    fi
}

# check for odd whitespace before build
check_odd_whitespace --cached

# determine working tree status
if ! git diff --quiet || \
    [ "$(git status --short | tail -1 | cut -f1 -d' ')" = '??' ]; then
    DIRTY=1
fi

# stash not staged for commit changes
if [ -n "$DIRTY" ]; then
    if ! git stash save --include-untracked --keep-index; then
        return 1
    fi
    trap pop_stashed EXIT
fi

if ! git diff --quiet HEAD; then
    # run build using staged changes only
    # use release build as with its optimization level compiler is able to issue
    # more warnings
    nice ionice make --jobs $(( `nproc` * 3 / 4 )) check release
    RESULT="$?"
else
    RESULT="0"
fi

# check for odd whitespace after build
check_odd_whitespace

# stashed changes (if any) are automatically restored by EXIT trap handler

# return result of build
exit $RESULT