tools/devshell/contrib/bazel2gn

#!/bin/bash
# Copyright 2024 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Source tree
### Syncs BUILD.gn and BUILD.bazel for targets that are dual-building in both.

## usage: fx bazel2gn [-d|--directory <path/to/dir>]... [-h|--help] [--no-build]
##
##   -h|--help       Print out this message.
##   -d|--directory  Directory to sync, repeatable.
##   --no-build      Skip building required dependencies.
##
## Updates BUILD.gn listed in this script based on the BUILD.bazel files in
## their directories.

set -eo pipefail

_script_dir="${BASH_SOURCE[0]%/*}";
if [[ "${_script_dir}" == "${BASH_SOURCE[0]}" ]]; then _script_dir="."; fi
readonly _script_dir

source "${_script_dir}/../lib/vars.sh" || exit $?
fx-config-read

source "${_script_dir}/../lib/bazel_utils.sh" || exit $?

declare -r BAZEL2GN_TARGET="//build/tools/bazel2gn"
declare -r BAZEL2GN_BIN="$(fx-get-bazel-workspace)/bazel-bin/build/tools/bazel2gn/bazel2gn_/bazel2gn"
declare -r BAZEL2GN_DIR_LIST="${FUCHSIA_BUILD_DIR}/bazel2gn_dir_list"

function main {
  local build=true
  local directories=()
  while [[ "${#}" -ge 1 ]]; do
    case "${1}" in
      -d|--directory)
        shift
        directories+=("${1}")
        ;;
      -h|--help)
        fx-command-help
        exit 0
        ;;
      --no-build)
        build=false
        ;;
      *)
        fx-error "Unexpected command line arg ${1}"
        fx-command-help
        exit 1
    esac
    shift
  done

  local use_dir_list=false
  if [[ "${#directories[@]}" -eq 0 ]]; then
    fx-gen # To make sure `BAZEL2GN_DIR_LIST` is up-to-date.
    use_dir_list=true
  fi

  # This Bazel build needs to run after `fx-gen`, which can clear out the symlinks in bazel-bin.
  if [[ "${build}" == "true" ]]; then
    fx-run-bazel false "$(fx-get-bazel)" build --config=host "${BAZEL2GN_TARGET}"
  fi

  if [[ "${use_dir_list}" == "true" ]]; then
    "${BAZEL2GN_BIN}" \
      --directory_list "${BAZEL2GN_DIR_LIST}" \
      --fuchsia_dir "${FUCHSIA_DIR}" \
      --gn_bin "${PREBUILT_GN}" \
      --buildifier_bin "${PREBUILT_BUILDIFIER}"
  else
    "${BAZEL2GN_BIN}" \
      --gn_bin "${PREBUILT_GN}" \
      --buildifier_bin "${PREBUILT_BUILDIFIER}" \
      "${directories[@]}"
  fi
}

main "$@"