support/download/git

   1 #!/usr/bin/env bash
   2
   3 # We want to catch any unexpected failure, and exit immediately
   4 set -e
   5
   6 # Download helper for git, to be called from the download wrapper script
   7 #
   8 # Call it as:
   9 #   .../git [-q] OUT_FILE REPO_URL CSET BASENAME
  10 #
  11 # Environment:
  12 #   GIT      : the git command to call
  13
  14 verbose=
  15 while getopts :q OPT; do
  16     case "${OPT}" in
  17     q)  verbose=-q; exec >/dev/null;;
  18     \?) printf "unknown option '%s'\n" "${OPTARG}" >&2; exit 1;;
  19     esac
  20 done
  21 shift $((OPTIND-1))
  22
  23 output="${1}"
  24 repo="${2}"
  25 cset="${3}"
  26 basename="${4}"
  27
  28 # Caller needs to single-quote its arguments to prevent them from
  29 # being expanded a second time (in case there are spaces in them)
  30 _git() {
  31     eval ${GIT} "${@}"
  32 }
  33
  34 # Try a shallow clone, since it is faster than a full clone - but that only
  35 # works if the version is a ref (tag or branch). Before trying to do a shallow
  36 # clone we check if ${cset} is in the list provided by git ls-remote. If not
  37 # we fall back on a full clone.
  38 #
  39 # Messages for the type of clone used are provided to ease debugging in case of
  40 # problems
  41 git_done=0
  42 if [ -n "$(_git ls-remote "'${repo}'" "'${cset}'" 2>&1)" ]; then
  43     printf "Doing shallow clone\n"
  44     if _git clone ${verbose} --depth 1 -b "'${cset}'" --bare "'${repo}'" "'${basename}'"; then
  45         git_done=1
  46     else
  47         printf "Shallow clone failed, falling back to doing a full clone\n"
  48     fi
  49 fi
  50 if [ ${git_done} -eq 0 ]; then
  51     printf "Doing full clone\n"
  52     _git clone ${verbose} --mirror "'${repo}'" "'${basename}'"
  53 fi
  54
  55 GIT_DIR="${basename}" \
  56 _git archive --prefix="'${basename}/'" -o "'${output}.tmp'" --format=tar "'${cset}'"
  57
  58 gzip <"${output}.tmp" >"${output}"