#!/bin/bash
# Copyright 2019 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=Build
### set up a build directory

## usage: fx set PRODUCT.BOARD [--with GNLABEL1,GNLABEL2,...]
##               [--release] [--auto-dir] [--args ARG] [--variant VARIANT]
##               [--with-base GNLABEL1,GNLABEL2,...]
##
## where PRODUCT is an entry from `//products` or `//vendor/*/products` and
## BOARD is an entry from `//boards` or `//vendor/*/boards`. Use the
## `fx list-products` and `fx list-boards` commands to see a list of
## possible products and boards (respectively). See the README.md in those
## directories for a description of the various options.
##
## Use `fx --dir BUILD_DIR set` to specify the build directory. If it begins with
## `//` or `out/` then it's taken as relative to FUCHSIA_DIR. Otherwise it should
## be an absolute path or a path relative to the current working directory that
## winds up in `FUCHSIA_DIR/out`. It defaults to `out/default`.
##
## This command stores the location of the build directory in the //.fx-build-dir
## file, which causes subsequent `fx` commands to use that build directory. Use
## `fx use` to switch build directories.
##
## Ensures Goma is ready (if Goma is enabled).
##
## This is a wrapper around running `gn gen --check=system BUILD_DIR --args ...`.
## If GN fails with an error, `fx set` does not change anything.
##
## optional arguments:
##   --args                Additional argument to pass to gn.  If the --args
##                         argument is given multiple times, all the specified
##                         arguments are passed to gn.
##                         N.B. Arguments must be expressed using GN's syntax.
##                         In particular this means that for strings they must
##                         be quoted with double-quotes, and the quoting must
##                         survive, for example, the shell. Thus when passing
##                         an argument that takes a string, pass it with
##                         something like --args=foo='"bar"'. E.g.,
##                         bash$ fx set core.x64 --args=foo='"bar"'
##                         More complicated arguments, e.g., lists, require
##                         their own special syntax. See GN documentation
##                         for the syntax of each kind of argument.
##   --auto-dir            Act like `fx --dir out/PRODUCT.BOARD set ...`.
##   --ccache|--no-ccache  Whether to use ccache during the build. Ccache attempts
##                         to make builds faster by caching build artifacts.
##                         Defaults to detecting whether the CCACHE_DIR environment
##                         variable is set to a directory.
##   --fuzz-with           Pass a sanitizer name, e.g. "--fuzz-with asan" to
##                         enable ALL supporting fuzzers.  Use --variant for
##                         individual fuzzers, e.g. "--variant asan-fuzzer/foo".
##   --goma|--no-goma      Whether to use the goma service during the build. Goma
##                         attempts to make builds faster using remote build
##                         servers. Defaults to detecting whether goma has been
##                         set up via `fx goma`.
##   --cxx-rbe             If set, use reclient (RBE) to build C++ targets.
##                         This takes precedence over --goma.
##                         Default: disabled
##   --rust-rbe            If set, use the remote backend (RBE) service for building
##                         Rust targets.  RBE offloads work onto remote servers and
##                         offers caching benefits to accelerate builds.
##                         Default: disabled
##   --ide                 Pass --ide=VALUE to gn when generating to create project
##                         files usable with that IDE. Useful values include "vs"
##                         for Visual Studio or "xcode" for Xcode.
##   --json-ide-script     Pass --json-ide-script=python_script to gn which runs
##                         the given python script after the JSON project file is
##                         generated when using --ide json. The path to the project
##                         file is given as the first argument to the script.
##                         The script may be a path or a gn label.
##   --netboot             Ensure that a network ramboot image is always built.
##   --no-ensure-goma      Skip ensuring that goma is started when using goma.
##   --release             an alias for "--args=is_debug=false"
##   --variant             Selects which runtime variant to use (e.g., asan) by
##                         passing a `select_variant=[VARIANT*,...]` argument
##                         to gn that collects all the --variant arguments in
##                         order. Variants are normal builds in most respects,
##                         but allow users to test different runtime settings
##                         for either the whole build or for a specific target.
##                         This can be specified by passing the variant name
##                         to this argument (e.g. `--variant asan`) for the
##                         former, or the variant name and the target name
##                         separated by a slash (e.g. `--variant asan/my_test`)
##                         for the latter.
##   --with GNLABEL        Labels of additional packages to include in the
##                         'universe' set of available packages. These packages
##                         can be run ephemerally. Multiple labels can be
##                         provided delimited by commas or the --with argument
##                         can be provided multiple times.
##   --with-base GNLABEL   Labels of additional packages to include in the
##                         'base' set of packages. These packages are included in
##                         the system image and can be updated only with an OTA.
##                         Multiple labels can be provided delimited by commas
##                         or the --with-base argument can be provided multiple
##                         times.
##   --with-cache GNLABEL  Labels of additional packages to include in the
##                         'cache' set of packages. These packages are made
##                         available on disk immediately after paving and in
##                         factory flows. These packages are not updated with
##                         an OTA, but are instead updated ephemerally. This
##                         cache of software can be evicted by the system if
##                         storage pressure arises or other policies indicate.
##                         Multiple labels can be provided delimited by commas
##                         or the --with-cache argument can be provided
##                         multiple times.
##   --with-host GNLABEL   Labels of additional host-only targets to be
##                         produced by the build. Multiple labels can be
##                         provided delimited by commas or the --with-host
##                         argument can be provided multiple times.
##   --cargo-toml-gen      Enable generation of Cargo.toml files.
##   --fint-params-path    Used to specify a path to a fint parameters file, as
##                         selected by `fx repro`. If set, no other flags that
##                         influence the build configuration should be set.
##   --dev                 Always recompile fx-set from source.
##
## Example:
##
##   $ fx set core.x64 --with //bundles/tests
##   -> build directory: out/default
##      board: //boards/x64.gni
##      product: //products/core.gni
##      universe: //bundles/tests (all test packages)

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

set -e

function main {
  fx-standard-switches "$@"
  set -- "${FX_ARGV[@]}"

  # Check if the --dev flag is set. If it is, then we'll always build fx-set
  # from source.
  local dev=false
  for arg; do
    shift
    if [ "$arg" = --dev ]; then
      dev=true
      continue
    fi
    # Include every arg besides --dev in the args we pass to fx-set.
    set -- "$@" "$arg"
  done

  # Cache the compiled executable for later invocations.
  readonly exe_path="${FX_CACHE_DIR}/fx-set"
  readonly revision_file="${FX_CACHE_DIR}/fx-set-revision"
  local current_revision
  current_revision="$(git --no-optional-locks -C "$FUCHSIA_DIR" rev-parse HEAD)"

  # Determine whether we need to rebuild the fx-set executable. We'll only
  # rebuild if the --dev flag is set, or if the cached version of fx-set was
  # built at a revision other than the current revision. We determine that by
  # storing the current HEAD of fuchsia.git in a cached version file whenever
  # we build fx-set, and then we rebuild if the current HEAD differs from the
  # revision referenced in the cached file.
  local should_rebuild=true
  if ! $dev && [ -f "$exe_path" ] && [ -f "$revision_file" ]; then
    local fx_set_revision
    fx_set_revision="$(head -n 1 "$revision_file")"
    if [ "$fx_set_revision" = "$current_revision" ]; then
      should_rebuild=false
    fi
  fi

  if $should_rebuild; then
    # Build in a temporary directory where we can arrange the module.
    #
    # Avoid "TMPDIR" since Go looks at that environment variable.
    BUILD_DIR=$(mktemp -d)
    trap 'rm -rf $BUILD_DIR' EXIT
    pushd "$BUILD_DIR" > /dev/null
    for target in go.{mod,sum} vendor; do
      ln -s "$FUCHSIA_DIR"/third_party/golibs/$target .
    done
    # fx-set's only local imports (direct and transitive) are from //tools. We
    # can symlink more top-level directories as necessary if fx-set ever needs
    # to import their code.
    ln -s "$FUCHSIA_DIR"/tools .
    # - GOPROXY=off enforces that we only use vendored dependencies and don't
    #   download anything.
    # - GO111MODULE=on ensures that we use modules for the build even if the
    #   user has GO111MODULE=off in their local environment.
    # - -buildvcs=false disables inclusion of version control information in the
    #   resulting binary. It's not needed, and including it requires `go build`
    #   to query for git status, which takes time and can trigger git garbage
    #   collection that messes with ninja build convergence.
    if ! CGO_ENABLED=0 GOPROXY=off GO111MODULE=on fx-command-run go build -buildvcs=false -o "$exe_path" ./tools/build/fx-set/cmd; then
      if ! $dev; then # If running in dev mode, compilation failures are expected.
        fx-error "Failed to build fx set."
      fi
      return 1
    fi
    popd > /dev/null

    # Record the current HEAD *after* building fx-set so that we always try
    # to rebuild on subsequent attempts if compilation fails the first time.
    echo "$current_revision" > "$revision_file"
  fi

  "$exe_path" "$@"
  status="$?"

  # Check for RBE requirements if enabled.
  fx-check-rbe-setup

  return "$status"
}

main "$@"