tools/bazel

#!/usr/bin/env bash
# Both bazelisk and bazel's native wrapper scripts will attempt to use the well-known executable
# named "tools/bazel" to run Bazel. The path of the original executable is stored in BAZEL_REAL.
set -euo pipefail
shopt -s nullglob

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"

# Jump into nix-shell if BAZEL_REAL is set to a /nix/store path and we aren't
# inside our shell yet.
if [[ "${BAZEL_REAL:-}" == /nix/store/* && -z "${MONOGON_NIXOS:-}" ]]; then
  echo "Detected Nix based bazel installation and we are not in a nix-shell, overriding to nix-shell." >&2
  USE_NIX_SHELL=yes
fi

# If the wrapper is called directly we check if nix-shell is available
# to automagically switch into the nix-shell. Otherwise complain and
# exit.
if [[ -z "${BAZEL_REAL:-}" ]]; then
  if [[ -x $(command -v nix-shell) ]]; then
    echo "BAZEL_REAL is not set and nix-shell is available, overriding to nix-shell" >&2
    USE_NIX_SHELL=yes
  else
    echo "BAZEL_REAL is not set and nix-shell not available. Please check the setup guide." >&2
    exit 1
  fi
fi

if [[ -n "${USE_NIX_SHELL:-}" ]]; then
  # Jump to project root since bwrap hangs if we aren't there
  cd "${DIR}/../"

  export COMMAND="bazel $*"
  export PWD="$OLDPWD"
  exec nix-shell
fi

# Short circuit if we're rebuilding the sandbox via third_party/sandboxroot/regenerate.sh.
if [[ -n ${MONOGON_SYSROOT_REBUILD:-} ]]; then
  echo "Skipping Bazel wrapper" >&2
  exec -a "$0" "${BAZEL_REAL}" "$@"
fi

SANDBOX="${DIR}/../.bazeldnf/sandbox/default"
BAZEL_ARGS="--noworkspace_rc --bazelrc ${DIR}/../.bazelrc.sandboxroot"

prechecks() {
  # Recommend using Bazelisk instead of Bazel's "bazel.sh" wrapper.
  # Skip if we're inside the Nix shell (which uses a customized Bazel build).
  if [[ -z "${BAZELISK_SKIP_WRAPPER:-}" && -z "${MONOGON_NIXOS:-}" ]]; then
    echo "############################################################" >&2
    echo "#  Please use Bazelisk to build the Monorepo. Using Bazel  #" >&2
    echo "#  directly may work, but is not recommended or supported. #" >&2
    echo "############################################################" >&2
  fi

  # Our local user needs write access to /dev/kvm. Warn if this is not the case.
  if ! touch /dev/kvm; then
    echo "###################################################################" >&2
    echo "#  Cannot write to /dev/kvm - please verify permissions.          #" >&2
    echo "#  Most tests require KVM and will not work. Builds still work.   #" >&2
    echo "#  On most systems, add your user to the kvm group and re-login.  #" >&2
    echo "###################################################################" >&2
  fi
}

intellij_patch() {
  # When IntelliJ's Bazel plugin uses //scripts/bin/bazel to either build targets
  # or run syncs, it adds a --override_repository flag to the bazel command
  # line that points @intellij_aspect into a path on the filesystem. This
  # external repository contains a Bazel Aspect definition which Bazel
  # executes to provide the IntelliJ Bazel plugin with information about the
  # workspace / build targets / etc...
  #
  # We need to patch the aspect definition to fix a number of bugs
  # to make it work with the Monogon monorepo.

  # Find all IntelliJ installation/config directories.
  local ij_home_paths=("${HOME}/.local/share/JetBrains/IntelliJIdea"*)
  # Get the newest one, if any.
  local ij_home=""
  if ! [[  ${#ij_home_paths[@]} -eq 0 ]]; then
      # Reverse sort paths by name, with the first being the newest IntelliJ
      # installation.
      IFS=$'\n'
      local sorted=($(sort -r <<<"${ij_home_paths[*]}"))
      unset IFS
      ij_home="${sorted[0]}"
  fi

  # If we don't have or can't find ij_home, don't bother with attempting to patch anything.
  if [[ -d "${ij_home}" ]]; then
      # aspect_path is the path to the aspect external repository that IntelliJ will
      # inject into bazel via --override_repository.
      local aspect_path="${ij_home}/ijwb/aspect"
      # Our copy of it.
      local patched_path="${ij_home}/ijwb/aspect-monogon"
      # Checksum of the patch that was used to create patched_path.
      local checksum_file="${patched_path}/checksum"
      # The patch
      local patch_file="${DIR}/../intellij/patches/bazel_intellij_aspect_filter.patch"
      # The checksum of the patch we're about to apply.
      local checksum
      checksum=$(sha256sum "$patch_file" | cut -d' ' -f1)

      # If the patched aspect repository doesn't exist, or the checksum of the patch
      # we're about to apply doesn't match the checksum of the patch that was used
      # to create the patched aspect repository, apply the patch.

      if ! [[ -d "${patched_path}" ]] || ! [[ "$(cat "${checksum_file}")" == "${checksum}" ]]; then
          echo "IntelliJ found at ${ij_home}, patching aspect repository." >&2
          # Copy the aspect repository to the patched path.
          rm -rf "${patched_path}"
          cp -r "${aspect_path}" "${patched_path}"
          # Apply the patch.
          patch -d "${patched_path}" -p1 < "${patch_file}"
          # Write the checksum of the patch to the checksum file.
          echo "${checksum}" > "${checksum_file}"
      else
          echo "IntelliJ found at ${ij_home}, aspect repository already patched." >&2
      fi
  fi
}

regenerate_sysroot() {
  local checksum_file="${SANDBOX}/checksum"
  local checksum_input=(
    ${DIR}/../third_party/sandboxroot/{repositories.bzl,BUILD.bazel}
    ${DIR}/../.bazelrc.sandboxroot
    ${DIR}/../tools/bazel
  )
  local checksum
  checksum="$(sha256sum <(cat "${checksum_input[@]}") | cut -d' ' -f1)"

  if [[ -f "${checksum_file}" ]] && [[ "$(cat "${checksum_file}")" == "${checksum}" ]]; then
    # Sysroot is up to date.
    return
  fi

  echo "Regenerating sysroot $SANDBOX ..." >&2
  rm -rf "$SANDBOX"
  "$BAZEL_REAL" ${BAZEL_ARGS} run //third_party/sandboxroot:sandboxroot

  # Manually resolve alternatives (https://github.com/rmohr/bazeldnf/issues/28)
  ln -r -s -f "${SANDBOX}/root/usr/bin/ld.bfd" "${SANDBOX}/root/usr/bin/ld"

  # Write checksum of the sysroot to a file in order to detect changes.
  echo "$checksum" > "${SANDBOX}/checksum"

  # Write Bazel config
  ROOT=$(realpath "$DIR/..")

  # We need the host's resolv.conf for some E2E tests which require internet access.
  cp /etc/resolv.conf "${ROOT}/.bazeldnf/sandbox/default/root/etc/resolv.conf"

  cat > "${DIR}/../.bazelrc.sandbox" <<EOF
# Autogenerated by tools/bazel. Manual changes can result in stale caches.
# Modify the generator instead.

# Mount directories from the generated Fedora sandbox root.
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/etc:/etc
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/usr:/usr
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/var:/var
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/run:/run
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/tmp:/tmp
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/lib64:/lib64
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/lib:/lib
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/bin:/bin
build --sandbox_add_mount_pair=${ROOT}/.bazeldnf/sandbox/default/root/sbin:/sbin

# Needed for the Go SDK shipped by rules_go to resolve its own GOROOT via /proc/self/exe.
build --sandbox_add_mount_pair=/proc

# Needed for python's multiprocessing lock implementation
# (_multiprocessing.SemLock for eg. mp.Queue), as used in EDK2's build system.
build --sandbox_add_mount_pair=/dev/shm

# Needed for qemu for tests.
build --sandbox_add_mount_pair=/dev/kvm

# Put a tmpfs on /tmp for better performance.
build --sandbox_tmpfs_path=/tmp
EOF

  echo "Done regenerating sysroot." >&2
}

prechecks
intellij_patch
regenerate_sysroot

# Find the --override_repository=intellij_aspect=[path]
# argument in $@ and replace the path with the patched version.
# This is surprisingly tricky - bash special-cases "$@" to expand
# as "$1" "$2" ... "$n" so that argv is preserved, so we need to
# modify the real $@ array.

for i in $(seq 1 $#); do
  if [[ "${!i}" == "--override_repository=intellij_aspect="* ]]; then
    new_arg="${!i/\/aspect/\/aspect-monogon}"
    set -- "${@:1:$((i-1))}" "${new_arg}" "${@:$((i+1))}"
  fi
done

# Bazel does not track the ambient environment, so we need to invalidate
# the entire build via an --action_env whenever the sandbox digest changes.
# This is strictly necessary to guarantee correctness.
export MONOGON_SANDBOX_DIGEST="$(cat "${SANDBOX}/checksum")"

# Ignore the host TMPDIR - it might be something funny like /run/user/1000,
# we want it to be /tmp inside the sandbox.
export TMPDIR=/tmp

exec -a "$0" "${BAZEL_REAL}" "$@"