# file      : bpkg-util/utility.bash.in
# license   : MIT; see accompanying LICENSE file

# Utility functions useful for implementing package management utilities.

if [ "$bpkg_util_utility" ]; then
  return 0
else
  bpkg_util_utility=true
fi

# Diagnostics.
#
function info  () { echo "$*" 1>&2; }
function error () { info "$*"; exit 1; }

# Trace a command line, quoting empty arguments as well as those that contain
# spaces.
#
function trace_cmd () # <cmd> <arg>...
{
  local s="+"
  while [ $# -gt 0 ]; do
    if [ -z "$1" -o -z "${1##* *}" ]; then
      s="$s '$1'"
    else
      s="$s $1"
    fi

    shift
  done

  info "$s"
}

# Trace the current function name and arguments.
#
function trace_func () # <args>...
{
  trace_cmd "${FUNCNAME[1]}" "$@"
}

# Trace and run a command.
#
function run () # <cmd> <arg>...
{
  trace_cmd "$@"
  "$@"
}

# Return lower-case URL scheme or empty string if the argument doesn't look
# like a URL.
#
function url_scheme () # <url>
{
  sed -n -re 's%^(.*)://.*$%\L\1%p' <<<"$1"
}

# Check that the git repository properly responds to the probing request
# before the timeout (in seconds). Noop for protocols other than HTTP(S).
#
function check_git_connectivity () # <repo-url> <timeout>
{
  local url="$1"
  local tmo="$2"

  local s
  s="$(url_scheme "$url")"

  if [ "$s" == "http" -o "$s" == "https" ]; then
    local u q

    u="$(sed -n -re 's%^([^?]*).*$%\1%p' <<<"$url")" # Strips query part.
    q="$(sed -n -re 's%^[^?]*(.*)$%\1%p' <<<"$url")" # Query part.

    if [ -z "$q" ]; then
      u="$u/info/refs?service=git-upload-pack"
    else
      u="$u/info/refs$q&service=git-upload-pack"
    fi

    # Here we limit the time for the whole operation.
    #
    curl -S -s --max-time "$tmo" "$u" >/dev/null
  fi
}