devshell/use

#!/bin/bash
# Copyright 2018 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.

### re-use a previous build directory set up by `fx set`

## usage: fx use DIR
##
## Switches further `fx` commands to using a different build directory.
## This only works if `fx set ... --build-dir DIR` succeeded previously
## (and DIR has not been removed since).  The next `fx build` or other
## such command will now refer to DIR.  The previous build directory is
## left in place, so you can switch back again with `fx use` later.

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?

function main {
  if [[ $# -ne 1 ]]; then
    fx-command-help
    return 1
  fi

  local -r build_dir="$1"

  if [[ "$build_dir" == /* ]]; then
    local -r full_build_dir="${build_dir}"
  else
    local -r full_build_dir="${FUCHSIA_DIR}/${build_dir}"
  fi

  if [[ -e "${full_build_dir}/args.gn" ]]; then
    fx-config-write "${build_dir}"
  else
    echo "\"${build_dir}\" is not a valid build dir."
    echo ""
    fx-command-help
    return 1
  fi
}

main "$@"