multithread

# SPDX-License-Identifier: GPL-2.0
# Copyright (C) 2019-present Team LibreELEC (https://libreelec.tv)

THREADCOUNT=${THREADCOUNT:-100%}

# This function is passed a list of package.mk paths to be processed.
# Each package.mk is sourced with relevant variables output in JSON format.
json_worker() {
  local packages="$@"
  local pkgpath hierarchy exited

  exit() { exited=1; }

  . config/options ""

  for pkgpath in ${packages}; do
    pkgpath="${pkgpath%%@*}"

    exited=0
    if ! source_package "${pkgpath}/package.mk" &>/dev/null; then
      unset -f exit
      die "$(print_color CLR_ERROR "FAILURE: sourcing package ${pkgpath}/package.mk")"
    fi

    [ ${exited} -eq 1 ] && continue

    [[ ${pkgpath} =~ ^${ROOT}/${PACKAGES}/ ]] && hierarchy="global" || hierarchy="local"

    cat <<EOF
  {
    "name": "${PKG_NAME}",
    "hierarchy": "${hierarchy}",
    "section": "${PKG_SECTION}",
    "bootstrap": "${PKG_DEPENDS_BOOTSTRAP}",
    "init": "${PKG_DEPENDS_INIT}",
    "host": "${PKG_DEPENDS_HOST}",
    "target": "${PKG_DEPENDS_TARGET}"
  },
EOF
  done
}
export -f json_worker

# This function is passed the build instruction for a single job.
# The function will run either "build <package>" or "install <package>".
# ${slot} is the job slot number, ie. 1-8 when THREADCOUNT=8.
# ${job} is the sequence within the total number of ${jobs}.
package_worker() {
  local slot=$1 job=$2 jobs=$3 args="$4"
  local task pkgname result status
  local addon istarget isaddon

  export MTJOBID=${slot} MTMAXJOBS=${jobs}

  read -r task pkgname <<< "${args}"

  . config/options "${pkgname}"

  [ ! -f "${THREAD_CONTROL}/parallel.pid" ] && echo "${PARALLEL_PID}" >"${THREAD_CONTROL}/parallel.pid"

  ${SCRIPTS}/${task} ${pkgname} 2>&1 && result=0 || result=1

  [[ ${pkgname} =~ :target$ || "${pkgname//:/}" = "${pkgname}" ]] && istarget="yes" || istarget="no"

  [[ "${MTADDONBUILD}" = "yes" && ( "${PKG_IS_ADDON}" = "yes" || "${PKG_IS_ADDON}" = "embedded" ) ]] && isaddon="yes" || isaddon="no"

  if [ "${isaddon}" = "yes" -a "${istarget}" = "yes" ]; then
    if [ ${result} -eq 0 ]; then
      ${SCRIPTS}/install_addon ${pkgname} 2>&1 && result=0 || result=1
    fi

    if [ ${result} -ne 0 ]; then
      echo "${PKG_NAME}" >>"${THREAD_CONTROL}/addons.failed"
    fi
  fi

  (
    flock --exclusive 95
    [ ${result} -eq 0 ] && status="DONE" || status="FAIL"
    num=$(< "${THREAD_CONTROL}/progress")
    mv "${THREAD_CONTROL}/progress" "${THREAD_CONTROL}/progress.prev"
    num=$((num + 1))
    echo ${num} >"${THREAD_CONTROL}/progress"
    printf "[%0*d/%0*d] [%-4s] %-7s %s\n" ${#jobs} ${num} ${#jobs} ${jobs} "${status}" "${task}" "${pkgname}" >&2
  ) 95>"${THREAD_CONTROL}/locks/.progress"

  if [ ${result} -eq 0 ]; then
    pkg_lock_status "IDLE"
  else
    pkg_lock_status "FAILED" "${pkgname}" "${task}"

    print_color CLR_ERROR "FAILURE: ${SCRIPTS}/${task} ${pkgname} has failed!\n"
  fi

  return ${result}
}
export -f package_worker

start_multithread_build() {
  local singlethread buildopts result=0

  # init thread control folder
  rm -rf "${THREAD_CONTROL}"
  mkdir -p "${THREAD_CONTROL}/locks"
  echo -1 >"${THREAD_CONTROL}/progress.prev"
  echo 0 >"${THREAD_CONTROL}/progress"
  echo 0 >"${THREAD_CONTROL}/status.max"
  touch "${THREAD_CONTROL}/status"

  # Increase file descriptors if building one thread/package
  [ "${THREADCOUNT}" = "0" ] && ulimit -n ${ULIMITN:-10240}

  # Bootstrap GNU parallel
  MTWITHLOCKS=no ${SCRIPTS}/build parallel:host 2>&1 || die "Unable to bootstrap parallel package"

  # determine number of available slots for the given THREADCOUNT - optimise logging for single threaded builds
  [ $(seq 1 32 | ${TOOLCHAIN}/bin/parallel --plain --no-notice --max-procs ${THREADCOUNT} echo {%} | sort -n | tail -1) -eq 1 ] && singlethread=yes || singlethread=no

  # create a single log file by default for a single threaded build (or the builder is a masochist)
  if [ "${singlethread}" = "yes" -a "${ONELOG,,}" != "no" ] || [ "${ONELOG,,}" = "yes" ]; then
    buildopts+=" --ungroup"
  else
    buildopts+=" --group"
  fi

  # When building addons, don't halt on error - keep building all packages/addons
  [ "${MTADDONBUILD}" = "yes" ] && buildopts+=" --halt never" || buildopts+=" --halt now,fail=1"

  # pipefail: return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status
  set -o pipefail

  cat ${_CACHE_PACKAGE_GLOBAL} ${_CACHE_PACKAGE_LOCAL} | \
    ${TOOLCHAIN}/bin/parallel --plain --no-notice --max-args 30 --halt now,fail=1 json_worker | \
    ${SCRIPTS}/genbuildplan.py --no-reorder --show-wants --build ${@} > "${THREAD_CONTROL}"/plan || result=1

  if [ ${result} -eq 0 ]; then
    save_build_config

    cat "${THREAD_CONTROL}"/plan | awk '{print $1 " " $2}' | \
      MTBUILDSTART=$(date +%s) MTWITHLOCKS=yes ${TOOLCHAIN}/bin/parallel \
        --plain --no-notice --max-procs ${THREADCOUNT} --joblog="${THREAD_CONTROL}/joblog" --plus ${buildopts} \
        package_worker {%} {#} {##} {} || result=1

    rm -f "${THREAD_CONTROL}/parallel.pid"
  fi

  set +o pipefail

  return ${result}
}