pre-commit

#!/bin/bash
set -e

RELEASE=1.7
JAR_NAME="google-java-format-${RELEASE}-all-deps.jar"
RELEASES_URL=https://github.com/google/google-java-format/releases/download
JAR_URL="${RELEASES_URL}/google-java-format-${RELEASE}/${JAR_NAME}"

CACHE_DIR="$HOME/.cache/google-java-format-git-pre-commit-hook"
JAR_FILE="$CACHE_DIR/$JAR_NAME"
JAR_DOWNLOAD_FILE="${JAR_FILE}.tmp"
JAR_PGP_ASC_FILE="${JAR_FILE}.asc"
PGP_SIGN_KEY_ID=E77417AC194160A3FABD04969A259C7EE636C5ED

if [[ ! -f "$JAR_FILE" ]]
then
    mkdir -p "$CACHE_DIR"
    curl -L "$JAR_URL" -o "$JAR_DOWNLOAD_FILE"
    cat >"$JAR_PGP_ASC_FILE" <<EOF
-----BEGIN PGP SIGNATURE-----

iQIzBAABCgAdFiEE53QXrBlBYKP6vQSWmiWcfuY2xe0FAlw2hwoACgkQmiWcfuY2
xe22Ww//YIHLWoQApuSmLdq4A1fcNOYbSpm6J9I2J1i2VoK84XSXP1XJTWsoYNbx
Y3Xx6I8p28AxH7LOWcdtds9enbF06blzz+1CxuSxvN32M7DDursiihsUYU9wmZVU
7V1ZYBtaYTYYw8C5U+UchcIVJrHdG9KrAiBcn1s76gigNAtCYV/1PyryupS1wcDZ
bdj48mI6adcnIpV+9D9W4rLuXw2Hg+ewktXTj3HYqkg+5Nvc/zP9ueBvqEsyh5Iz
3+69egblhuN7gRaEWarlYfJ2n/kF9T/UMAkQrWD8+9cOgUcgTHkNADNOLpmDH6t7
OYvZhgwQT920ZJgGP8e3DGyvMxBMxlr19ciTT19HL5qglyhFm/SeHvFdpaHkIjb9
CmASWrlkALdEv2gPx+m79EJifyK5tYtViZgLhfjwYkS/opw5TfJX0+Ngh9ehgune
c6TgEIzRQAEQ/9QoVk2crGT/lhXnJI3Zid7cSP2/fRdui91KaKGi9qFvXyJf7XKI
vH0De+e3yZN/GXLYyQSUzmdQU8HMF9iuc81CT1ANgU+e9HU5k9FWSPHrA3gN7CKt
/a3qIsIBpcdKe9zcPxSoEqRzVNept4IhszgiIVxZPNrPShzCRbS1sGURoOTbSFSP
+aKWNFoswX/RANGQVajOyfF5mJ3lB4N0u2eI0HIR3NzNx0HN+2Q=
=+/96
-----END PGP SIGNATURE-----
EOF

    if ! gpg --list-keys "$PGP_SIGN_KEY_ID"
    then
        gpg --keyserver hkp://pgp.mit.edu --recv-key "$PGP_SIGN_KEY_ID"
    fi
    gpg --verify "$JAR_PGP_ASC_FILE" "$JAR_DOWNLOAD_FILE"
    mv "$JAR_DOWNLOAD_FILE" "$JAR_FILE"
fi

changed_java_files=$(git diff --cached --name-only --diff-filter=ACMR | grep ".*java$" || true)
if [[ -n "$changed_java_files" ]]
then
    echo "Reformatting Java files: $changed_java_files"
    if ! java -jar "$JAR_FILE" --replace --set-exit-if-changed $changed_java_files
    then
        echo "Some files were changed, aborting commit!" >&2
        exit 1
    fi
else
    echo "No Java files changes found."
fi