tools/devshell/host-tool

#!/bin/bash
# Copyright 2020 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=Run, Inspect and Debug
#### PREBUILTS=${PREBUILT_CLANG_DIR}
### run a host tool produced by the build

## usage: fx host-tool [--no-build] TOOLNAME [TOOL_ARGS...]
##
## This looks for a tool named TOOLNAME in tool_paths.json and executes it
## with the provided TOOL_ARGS.
##    --no-build       does not attempt to build the tool if it does not exist
##    --print          print the tool path instead of executing it. TOOL_ARGS
##                     is ignored, but build behaves the same.
##
## If the tool is not known to the build system, for example if it is not in
## the GN build graph, a proper message will be printed and the script fails.
## This script is specially useful for other scripts, via fx-command-run,
## although it can also be used directly by final users.
##
## The tool will be built if host-tool is being run interactively or invoked by
## an agent, otherwise an error will be produced if the tool is missing.

set -e

# shellcheck source=tools/devshell/lib/vars.sh
source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?
# shellcheck source=tools/devshell/lib/host_symbolizer.sh
source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/host_symbolizer.sh || exit $?
fx-config-read

build=true
print_only=false

while [[ $1 == --* ]]; do
  if [[ $1 == '--no-build' ]]; then
    build=false
    shift
  elif [[ $1 == '--print' ]]; then
    print_only=true
    shift
  else
    fx-error "Unrecognized option: $1"
    fx-command-help
    exit 1
  fi
done

if [[ $# -eq 0 || $1 == -* ]]; then
  fx-error "Invalid syntax"
  fx-command-help
  exit 1
fi

toolname="$1"
shift

# list-build-artifacts fails with a reasonable error message if tool is unknown
toolpath="$(fx-command-run list-build-artifacts --name "${toolname}" --expect-one tools)"

resolved_tool="$(realpath -m "${FUCHSIA_BUILD_DIR}/${toolpath}")"
if [[ "${resolved_tool}" == "${FUCHSIA_DIR}/prebuilt/"* ]]; then
  fx-ensure-prebuilt "${resolved_tool}"
fi

if [[ ! -f "${FUCHSIA_BUILD_DIR}/${toolpath}" ]]; then
  tool_label="$(fx-command-run list-build-artifacts --show-label --name "${toolname}" --expect-one tools)"
  # If the desire is to build, then it's important for the build to
  # have stdout and stderr to print to. There are two possible
  # conditions, one is that host-tool is being run with stdout going to
  # a terminal, the other is that stdout is being captured, for example
  # if the user is running `fx set-device`. In the latter case it is
  # desirable to attach the build to the controlling terminal, if there
  # is one. In the case where there is not, fall back to printing an
  # error, as if --no-build was passed. If stderr is also redirected,
  # then the build is unconditionally skipped unless invoked by an agent.
  if ! fx-is-stderr-tty && ! is_invoked_by_agent; then
    build=false
  fi

  if ! $build; then
    fx-error "Tool \"${toolname}\" is required by this command and has not been built."
    fx-error "Please build it first: fx build ${tool_label}"
    exit 2
  fi

  {
    echo "Building required tool '${toolname}' from \"${tool_label}\"..."
    fx-command-run build "${tool_label}" || exit $?
  } 1>&2
fi

if $print_only; then
  echo "${FUCHSIA_BUILD_DIR}/${toolpath}"
else
  exec "${FUCHSIA_BUILD_DIR}/${toolpath}" "$@"
fi