#!/bin/bash
# Copyright 2017 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.

### build Fuchsia

## usage: fx build [ninja option,...] [target,...]

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"/lib/vars.sh
fx-config-read

readonly LOCK_FILE="${FUCHSIA_DIR}"/.build_lock

# Use a lock file around a command if possible.
# Print a message if the lock isn't immediately entered,
# and block until it is.
function try_locked {
  if !(command -v shlock >/dev/null); then
    # Can't lock! Fall back to unlocked operation.
    "$@"
  elif shlock -f "${LOCK_FILE}" -p $$; then
    # This will cause a deadlock if any subcommand calls back to fx build,
    # because shlock isn't reentrant by forked processes.
    cmd_locked "$@"
  else
    echo "Locked by ${LOCK_FILE}..."
    while ! shlock -f "${LOCK_FILE}" -p $$; do sleep .1; done
    cmd_locked "$@"
  fi
}

# Exit trap to clean up lock file
function _rmlock () {
  [[ -n "${LOCK_FILE}" ]] && rm -f "${LOCK_FILE}"
}

function cmd_locked {
  trap _rmlock EXIT
  "$@"
  exit $?
}

function main {
  # TERM is passed for the pretty ninja UI
  # PATH is passed as some tools are referenced via $PATH due to platform differences.
  # TMPDIR is passed for Goma on macOS. TMPDIR must be set, or unset, not
  # empty. Some Dart build tools have been observed writing into source paths
  # when TMPDIR="" - it is deliberately unquoted and using the ${+} expansion
  # expression).
  try_locked env -i TERM="${TERM}" PATH="${PATH}" ${TMPDIR+"TMPDIR=$TMPDIR"} \
    "${FUCHSIA_DIR}/buildtools/ninja" -j "$(fx-choose-build-concurrency)" \
                                      -l "$(fx-cpu-count)" \
                                      -C "${FUCHSIA_BUILD_DIR}" "$@"
}

main "$@"