revision-gen

#!/bin/bash

# Calculates the number of revisions since the tag of a given version. Useful as an incremention build sequence
# when git metadata is missing, for example in tarballs, this script uses a fixed file "./tarball-revision" to retrieve
# the revision.  Source build therefore should save revision into the tarball

if [ "$#" == "0" ]; then
    VERSION="15.06"
else
    VERSION=$1
fi

if test -f ./tarball-revision; then
    cat ./tarball-revision
    exit
fi

# projects that are submodules should add to their parent's revision otherwise 
# if there is a rebuild because a dependency triggered a reinstall then package
# wouldn't be a new revision number and not trigger reinstall on update
if test -d ../.git; then
  abs_path=`readlink -f $0`
  parent=`cd ..; $abs_path $@`
  parent_rev=${parent%.*}
fi


VER_REV=`git describe --abbrev=5 --match="v${VERSION}" HEAD`
if [ "$?" != "0" ]; then
    echo "Could not find tag v$VERSION" 1>&2
    exit 1
fi
REV=`echo "${VER_REV}" | sed -e 's/^v[0-9.]\+-//g' -e 's/-g\?/./g'`
if [ -n "$parent_rev" ]; then
  echo $[ ${parent_rev} + ${REV%.*} ].${REV#*.}
else
  echo $REV
fi