#!/bin/bash

# We want to catch any command failure, and exit immediately
set -e

# Download helper for svn
# Call it with:
#   $1: svn repo
#   $2: svn revision
#   $3: package's basename (eg. foobar-1.2.3)
#   $4: output file
# And this environment:
#   SVN      : the svn command to call
#   BUILD_DIR: path to Buildroot's build dir

repo="${1}"
rev="${2}"
basename="${3}"
output="${4}"

repodir="${basename}.tmp-svn-checkout"
tmp_output="$( mktemp "${output}.XXXXXX" )"

cd "${BUILD_DIR}"
# Remove leftovers from a previous failed run
rm -rf "${repodir}"

# Play tic-tac-toe with temp files
# - first, we download to a trashable location (the build-dir)
# - then we create a temporary tarball in the final location, so it is
#   on the same filesystem as the final file
# - finally, we atomically rename to the final file

ret=1
if ${SVN} export "${repo}@${rev}" "${repodir}"; then
    if tar czf "${tmp_output}" "${repodir}"; then
        mv "${tmp_output}" "${output}"
        ret=0
    fi
fi

# Cleanup
rm -rf "${repodir}" "${tmp_output}"
exit ${ret}