tagver

#!/bin/bash
#
# tagver -- Generate a useful version from tags, revisions
#           and dirt.  Works with git and mercurial. Run
#           from the top directory of the repository.
#
# Copyright 2010, Aron Griffis <agriffis@n01se.net>
# Released under the GNU GPL v2

die() {
    echo "${0##*/} error: ${1:-giving up}" >&2
    exit 1
}

tagver-git() {
    type git >/dev/null || die "missing git binary"

    declare ver

    # v1-1-g14beccc-dirty or a546953-dirty
    ver=$(git describe --always --tags ${1:---dirty=+}) || die
    ver=${ver#v}                # 1-1-g14beccc+
    ver=${ver//-/.}             # 1.1.g14beccc+
    [[ $ver == *.* ]] || ver=0.0.$ver  # no tags

    echo "$ver"
}

tagver-hg() {
    type hg >/dev/null || die "missing hg binary"

    declare cset_tag cset tag cur dirty

    # Get the changeset associated with the most recent tag
    # changeset:   42:ab2fe458b727
    # tag:         v1
    ct=$(hg log -r "${1:-.}:0" -X .hgtags | grep -m1 -B1 '^tag: *v\?[0-9]')

    # Extract the tag and changeset; maybe blank if there are no tags
    tag=$(awk '$1=="tag:"      {print $2;exit}' <<<"$ct") # v1
    tag=${tag#v}                                          # 1
    ct=$(awk  '$1=="changeset:"{print $2;exit}' <<<"$ct") # 42:ab2fe458b727

    # What's the current (or requested) changeset?
    cur=$(hg log -r "${1:-.}:0" -X .hgtags \
        | awk '$1=="changeset:" {print $2; exit}')        # 45:fe458b727ab2

    # Check if the working directory is dirty
    [[ -n $1 ]] || dirty=$(hg id -n | grep -o +)          # +

    echo -n "${tag:-0.0}"
    [[ "$cur" == "$cset" ]] || echo -n ".${cur/:/.}"
    echo "$dirty"
}

if [[ -d .git ]]; then
    tagver-git "$@"
elif [[ -d .hg ]]; then
    tagver-hg "$@"
else
    die "dunno"
fi