#!/usr/bin/env bash

# Copyright 2018 The Fuchsia Authors
#
# Use of this source code is governed by a MIT-style
# license that can be found in the LICENSE file or at
# https://opensource.org/licenses/MIT

# This script will run the checkers in the Fuchsia module of Clang-tidy on
# Zircon. It requires either a prebuilt Clang toolchan or a Clang toolchain
# built from official Clang repository. For instructions on how to obtain a
# prebuilt toolchain or build the toolchain from scratch, please refer to
# document at
# https://fuchsia.googlesource.com/zircon/+/master/docs/getting_started.md

set -eu

# Path to toolchain
TOOLCHAIN_PREFIX=""

function func_help {
  echo "USAGE: clang-tidy-zircon <options> [files ...]"
  echo ""
  echo "Make sure that you generate the compile_commands.json file with the "
  echo "-c flag (or USE_CLANG=true if using make directly)."
  echo "options:"
  echo ""
  echo "-p <toolchain prefix>     : path to the directory containing bin/clang"
  echo "-h                        : for help"
  exit 1
}

SOURCE="${BASH_SOURCE[0]}"
while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  SCRIPT_DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
  SOURCE="$(readlink "$SOURCE")"
  # if $SOURCE was a relative symlink, we need to resolve it relative to the
  # path where the symlink file was located
  [[ "$SOURCE" != /* ]] && SOURCE="$SCRIPT_DIR/$SOURCE"
done
SCRIPT_DIR="$( cd -P "$( dirname "$SOURCE" )" && pwd )"
ZIRCON_ROOT="$SCRIPT_DIR/.."

# Read args from command line
while getopts "p:t:hn" opt; do
  case $opt in
    p) TOOLCHAIN_PREFIX="$OPTARG";;
    h) func_help;;
    \?)
      echo "Invalid option"
      func_help
  esac
done
shift $((OPTIND -1))

# Determine the clang prefix
if [ -z "$TOOLCHAIN_PREFIX" ]; then
  # User did not provide toolchain prefix
  # Assume user prefer prebuilt toolchain
  PREBUILT_DIR="$ZIRCON_ROOT/prebuilt/downloads/clang"
  if [ ! -d "$PREBUILT_DIR" ]; then
    echo "Toolchain prefix is not defined and prebuilt toolchain has not yet been downloaded."
    echo "Abort!"
    exit -1
  fi
  TOOLCHAIN_PREFIX="$PREBUILT_DIR"
fi

# Change dir to zircon
cd "$ZIRCON_ROOT"
# Check the prebuilt clang-tidy binary
CLANGTIDY="$TOOLCHAIN_PREFIX/bin/clang-tidy"
if [ ! -f "$CLANGTIDY" ]; then
  echo "$CLANGTIDY not found in prebuilts."
  echo "Ensure the toolchain prefix includes the clang-tidy binary."
  echo ""
  exit 0
fi

cd "$ZIRCON_ROOT"
# Check compile_commands.json
COMPILE_COMMANDS="$ZIRCON_ROOT/compile_commands.json"
if [ ! -f "$COMPILE_COMMANDS" ]; then
  echo "compile_commands.json missing, see "
  echo "https://fuchsia.googlesource.com/zircon/+/master/docs/editors.md for "
  echo "instructions on how to generate it (make sure you use the "
  echo "USE_CLANG=true option when building zircon)."
  exit -1
fi

# Due to a bug in clang-tidy (https://bugs.llvm.org/show_bug.cgi?id=34900),
# the checks have to be specified here instead of in the .clang-tidy file
# if we're not running clang-analyzer-* checks.
$CLANGTIDY -checks="-*,fuchsia-*" $@