pre-commit

#!/bin/sh

#
# Copyright 2021 Philipp Salvisberg <philipp.salvisberg@trivadis.com>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

# See https://github.com/Trivadis/plsql-formatter-settings/hook for usage instructions.

# -----------------------------------------------------------------------------
# Configuration section - Change values of variables to fit your needs.
# -----------------------------------------------------------------------------

# Git pre-commit formatter variant:
#    1) tvdformat command via SQLcl (command must be registered via $SQLPATH/login.sql)
#    2) format.js script via SQLcl (the default)
#    3) tvdformat.jar standalone executable JAR (includes `format.js`, no SQLcl required)
FORMATTER_VARIANT="2"

# Location of the local clone of the plsql-formatter-settings Git repository.
# Used as root directory of known subdirectories and files in the Git respository.
FORMATTER_GITHUB_DIR="$HOME/github/trivadis/plsql-formatter-settings"

# Location of the `format.js` JavaScript file. Required only for $FORMATTER_VARIANT 2.
FORMATTER_JS="$FORMATTER_GITHUB_DIR/sqlcl/format.js"

# Location of the `tvdformat.jar` JAR. Required only for $FORMATTER_VARIANT 3.
FORMATTER_JAR="$FORMATTER_GITHUB_DIR/standalone/target/tvdformat.jar"

# Location of the SQL Developer's settings
FORMATTER_SQLDEV_SETTINGS_DIR="$FORMATTER_GITHUB_DIR/settings/sql_developer"

# Formatter options beside $FORMATTER_SCOPE
FORMATTER_EXT="sql,prc,fnc,pks,pkb,trg,vw,tps,tpb,tbp,plb,pls,rcv,spc,typ,aqt,aqp,ctx,dbl,tab,dim,snp,con,collt,seq,syn,grt,sp,spb,sps,pck"
FORMATTER_MEXT="markdown,mdown,mkdn,md"
FORMATTER_XML="$FORMATTER_SQLDEV_SETTINGS_DIR/trivadis_advanced_format.xml"
FORMATTER_ARBORI="$FORMATTER_SQLDEV_SETTINGS_DIR/trivadis_custom_format.arbori"
FORMATTER_OPTS="ext=$FORMATTER_EXT mext=$FORMATTER_MEXT xml=$FORMATTER_XML arbori=$FORMATTER_ARBORI"

# SQLcl options. 
# `-nolog` is mandatory and the use of `-` instead of `/` makes it compatible across all platforms. 
SQLCL_OPTS="-nolog -noupdates -S"

# Show formatter command before execution? true/false.
FORMATTER_SHOW_COMMAND=true

# -----------------------------------------------------------------------------
# Subroutines code section - Changes should not be required.
# -----------------------------------------------------------------------------

function get_staged_files() {
    # Only added (A) and modified (M) files need to be formatted.
    # Only configured file extensions will be formatted, hence no need to apply additional filters.
    STAGED_FILES=`git diff --cached --name-only --diff-filter=AM`
}

function exit_when_sqlcl_not_found() {
    # Check only for existance of sql command. 
    # SQLcl has various ways to find a suitable Java installation.
    if ! type sql >/dev/null 2>&1; then
        echo "Warning: Bypassing formatter. SQLcl not found in path."
        exit 0
    fi
}

function exit_when_login_sql_not_found() {
    if [ -z ${SQLPATH} ]; then
        echo "Warning: Bypassing formatter. SQLPATH environment variable not defined."
        exit 0
    fi
    if ! test -f "${SQLPATH}/login.sql"; then
        # If login.sql is missing then the tvdformat command cannot be registered.
        echo "Warning: Bypassing formatter. $SQLPATH/login.sql not found."
        exit 0
    fi
}

function exit_when_java_not_found() {
    if ! type java >/dev/null 2>&1; then
        echo "Warning: Bypassing formatter. Java not found in path."
        exit 0
    fi
}

function exit_when_format_js_not_found() {
    if ! test -f "$FORMATTER_JS"; then
        echo "Warning: Bypassing formatter. $FORMATTER_JS not found."
        exit 0
    fi
}

function exit_when_tvdformat_jar_not_found() {
    if ! test -f "$FORMATTER_JAR"; then
        echo "Warning: Bypassing formatter. $FORMATTER_JAR not found."
        exit 0
    fi
}

function exit_when_formatter_prerequisites_are_missing() {
    # Provide information why changes are committed without calling the formatter.
    # Formatting code is optional from a technical point of view.
    # As a result we do not want the pre-commit hook to abort.
    case $FORMATTER_VARIANT in
        "1") 
            exit_when_sqlcl_not_found
            exit_when_login_sql_not_found
            ;;
        "2")
            exit_when_sqlcl_not_found
            exit_when_format_js_not_found
            ;;
        "3")
            exit_when_java_not_found
            exit_when_tvdformat_jar_not_found
            ;;
    esac
}

function exit_when_using_non_default_staging_area() {
    # Cannot check in EGit/JGit based environments because $GET_INDEX_FILE is not set.
    if [[ "$GIT_INDEX_FILE" != ".git/index" && "$GIT_INDEX_FILE" != "" ]]; then
        echo "Warning: Bypassing formatter due to non-default Git staging area usage."
        echo "         This happens when using 'git commit --only' or similar."
        exit 0
    fi
}

function exit_when_partially_staged_files_exist() {
    if [[ ! -z $(git diff -- $STAGED_FILES) ]]; then
        echo "Warning: Bypassing formatter due to partial commit."
        echo "         This happens when staging some hunks/lines instead of a complete file."
        exit 0
    fi
}

function exit_when_no_staged_files_found() {
    STAGED_FILES_COUNT=`echo $STAGED_FILES | wc -w`
    if [ "$STAGED_FILES_COUNT" -eq "0" ]; then
        echo "Info: No added or modified files. Formatting not necessary."
        exit 0
    fi
}

function check_if_formatter_can_be_applied() {
    if [[ "$ROOT_PATH" = "" ]]; then
        # Provide information why changes are committed without calling the formatter.
        # Formatting code is de facto optional. As a result we do not want the pre-commit hook to abort.
        exit_when_no_staged_files_found
        exit_when_formatter_prerequisites_are_missing
        exit_when_using_non_default_staging_area
        exit_when_partially_staged_files_exist
    fi
}

function create_json_file() {
    TEMPFILE=`mktemp`
    rm $TEMPFILE
    case $OSTYPE in
        msys*)
            # Git Bash, mount point /tmp is not visible in Java and leads to a file not found error.
            # Original $TMP and $TEMP environment variables are overwritten by Git Bash.
            TEMPDIR=`mount | grep 'on /tmp' | awk '{print $1}'`
            JSONFILE=${TEMPDIR}/`basename $TEMPFILE`.json
            ;;
        *)
            JSONFILE=${TEMPFILE}.json
            ;;
    esac

    # Create JSON array with files to be formatted.
    echo "$STAGED_FILES" \
        | awk ' \
            BEGIN { ORS = ""; print "[\n"; } \
            { printf "%s", (NR>1 ? ",\n" : ""); print "  \""$1"\""; } \
            END { print "\n]\n"; }' \
        > $JSONFILE
}

function set_formatter_scope() {
    if [[ "$ROOT_PATH" != "" ]]; then
        # To format a file or a directory without calling "git commit". 
        FORMATTER_SCOPE="$ROOT_PATH"
    else
        # Format staged files via "git commit".
        FORMATTER_SCOPE=$JSONFILE
    fi 
}

function format_via_tvdformat_command() {
    if [ "$FORMATTER_SHOW_COMMAND" = true ]; then
        echo "sql $SQLCL_OPTS"
        echo "tvdformat $FORMATTER_SCOPE $FORMATTER_OPTS"
    fi
    sql $SQLCL_OPTS <<EOF
tvdformat $FORMATTER_SCOPE $FORMATTER_OPTS
exit
EOF
}

function format_via_format_js() {
    if [ "$FORMATTER_SHOW_COMMAND" = true ]; then
        echo "sql $SQLCL_OPTS"
        echo "script $FORMATTER_JS $FORMATTER_SCOPE $FORMATTER_OPTS"
    fi
    sql $SQLCL_OPTS <<EOF
script $FORMATTER_JS $FORMATTER_SCOPE $FORMATTER_OPTS
exit
EOF
}

function format_via_tvdformat_jar() {
    if [ "$FORMATTER_SHOW_COMMAND" = true ]; then
        echo "java -jar $FORMATTER_JAR $FORMATTER_SCOPE $FORMATTER_OPTS"
    fi
    java -jar $FORMATTER_JAR $FORMATTER_SCOPE $FORMATTER_OPTS
}

function format_staged_files_in_workspace() {
    # Ignoring files that cannot be formatted (for whatever reason).
    case $FORMATTER_VARIANT in
        "1") format_via_tvdformat_command;;
        "2") format_via_format_js;;
        "3") format_via_tvdformat_jar;;
    esac
}

function update_staging_area() {
    for f in $STAGED_FILES
    do
        if [[ -z $(git diff head -- $f) ]]; then
            # No pending change after calling formatter, do not commit this file.
            git reset $f
            echo "Info: Removed $f from staging area (no changes left after formatting code)."
        else
            # Ensure formatter changes are considered in this commit
            git add $f
        fi
    done
}

function abort_on_empty_staging_area() {
    if [[ "$ROOT_PATH" = "" ]]; then
        STAGED_FILES_COUNT=`git diff --cached --name-only | wc -l`
        if [ "$STAGED_FILES_COUNT" -eq "0" ]; then
            echo "Error: Aborting commit. No files found in staging area."
            echo "       This may happen when all changes are eliminated by the formatter."
            exit 1
        fi
    fi
}

# -----------------------------------------------------------------------------
# Main code section - Changes should not be required.
# -----------------------------------------------------------------------------

ROOT_PATH=$1
get_staged_files
check_if_formatter_can_be_applied
create_json_file
set_formatter_scope
format_staged_files_in_workspace
update_staging_area
abort_on_empty_staging_area
exit 0