scripts/setup_engine.sh

#!/bin/bash
#
# Copyright 2022 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.
#
# Sets up the Flutter Engine repo.
#
# This takes a bit of time and is only necessary if you want to test
# Flutter Engine changes or upgrade the version of Flutter Engine used by this
# repository, so it's a separate script from bootstrap.sh.
#
# TODO(akbiggs): It would simplify the workflow significantly to
# make third_party/engine a git submodule (we could get rid of setup_engine.sh),
# however I think the Engine source needs to be fetched using
# gclient in order for building to work per
# https://github.com/flutter/flutter/wiki/Setting-up-the-Engine-development-environment.
#
# Usage:
#   setup_engine.sh --github-username <github_username>
#
# Arguments:
#   --github-username: Your GitHub username where your fork of Flutter Engine
#                      lives. Required.

set -e # Fail on any error.
source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/helpers.sh || exit $?

ensure-embedder-dir

# Parse arguments.
github_username=""
while [[ $# -gt 0 ]]; do
  case $1 in
    --github-username)
      shift # past argument
      github_username=$1
      shift # past value
      ;;
    *)
      echo-error "Unknown argument: $1"
      exit 1
      ;;
  esac
done

if [[ -z "${github_username}" ]]
then
  echo-error "Usage: $0 --github-username <github_username>"
  exit 1
fi

engine_revision="$(cat ${FUCHSIA_EMBEDDER_DIR}/third_party/dart-pkg/internal/flutter/flutter/bin/internal/engine.version)"

if [[ -d "${embedder_engine_dir}" ]]
then
  echo-error "${embedder_engine_dir} already exists."
  echo-error "If you're trying to create it from scratch, delete that folder first and"
  echo-error "then re-run this script."
  exit 1
fi

echo-info "Initializing gclient..."
"${embedder_depot_tools}"/gclient

echo-info "Fetching flutter/engine into ${embedder_engine_dir}..."
mkdir "${FUCHSIA_EMBEDDER_DIR}"/third_party/engine
cp "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/setup_engine_gclient_template "${FUCHSIA_EMBEDDER_DIR}"/third_party/engine/.gclient
sed -i "s/<your_name_here>/$github_username/g" "${FUCHSIA_EMBEDDER_DIR}"/third_party/engine/.gclient

pushd "${FUCHSIA_EMBEDDER_DIR}"/third_party/engine

"${embedder_depot_tools}"/gclient sync

echo-info "Adding 'upstream' remote to ${embedder_engine_dir}/flutter..."
git -C "${embedder_engine_dir}"/flutter remote add upstream git@github.com:flutter/engine.git

popd  # "${FUCHSIA_EMBEDDER_DIR}"/third_party/engine

echo-info "Syncing ${embedder_engine_dir}/flutter to ${engine_revision}..."
"${FUCHSIA_EMBEDDER_DIR}"/scripts/sync_engine_to_revision.sh "${engine_revision}"

echo-info "Done! You can now build and test Flutter Engine changes locally by following"
echo-info "https://fuchsia.googlesource.com/flutter-embedder/+/refs/heads/main/docs/making_engine_changes.md#workflow"