GIT-VERSION-GEN

#!/bin/sh

DEF_VER=v2.48.0-rc0

LF='
'

if test "$#" -ne 3
then
    echo >&2 "USAGE: $0 <SOURCE_DIR> <INPUT> <OUTPUT>"
    exit 1
fi

SOURCE_DIR="$1"
INPUT="$2"
OUTPUT="$3"

if ! test -f "$INPUT"
then
	echo >&2 "Input is not a file: $INPUT"
	exit 1
fi

# Protect us from reading Git version information outside of the Git directory
# in case it is not a repository itself, but embedded in an unrelated
# repository.
GIT_CEILING_DIRECTORIES="$SOURCE_DIR/.."
export GIT_CEILING_DIRECTORIES

# First see if there is a version file (included in release tarballs),
# then try git-describe, then default.
if test -f "$SOURCE_DIR"/version
then
	VN=$(cat "$SOURCE_DIR"/version) || VN="$DEF_VER"
elif {
		test -d "$SOURCE_DIR/.git" ||
		test -d "${GIT_DIR:-.git}" ||
		test -f "$SOURCE_DIR"/.git;
	} &&
	VN=$(git -C "$SOURCE_DIR" describe --match "v[0-9]*" HEAD 2>/dev/null) &&
	case "$VN" in
	*$LF*) (exit 1) ;;
	v[0-9]*)
		git -C "$SOURCE_DIR" update-index -q --refresh
		test -z "$(git -C "$SOURCE_DIR" diff-index --name-only HEAD --)" ||
		VN="$VN-dirty" ;;
	esac
then
	VN=$(echo "$VN" | sed -e 's/-/./g');
else
	VN="$DEF_VER"
fi

GIT_VERSION=$(expr "$VN" : v*'\(.*\)')
GIT_BUILT_FROM_COMMIT=$(git -C "$SOURCE_DIR" rev-parse -q --verify HEAD 2>/dev/null)
GIT_DATE=$(git -C "$SOURCE_DIR" show --quiet --format='%as' 2>/dev/null)
if test -z "$GIT_USER_AGENT"
then
	GIT_USER_AGENT="git/$GIT_VERSION"
fi

# While released Git versions only have three numbers, development builds also
# have a fourth number that corresponds to the number of patches since the last
# release.
read GIT_MAJOR_VERSION GIT_MINOR_VERSION GIT_MICRO_VERSION GIT_PATCH_LEVEL trailing <<EOF
$(echo "$GIT_VERSION" 0 0 0 0 | tr '.a-zA-Z-' ' ')
EOF

sed -e "s|@GIT_VERSION@|$GIT_VERSION|" \
	-e "s|@GIT_MAJOR_VERSION@|$GIT_MAJOR_VERSION|" \
	-e "s|@GIT_MINOR_VERSION@|$GIT_MINOR_VERSION|" \
	-e "s|@GIT_MICRO_VERSION@|$GIT_MICRO_VERSION|" \
	-e "s|@GIT_PATCH_LEVEL@|$GIT_PATCH_LEVEL|" \
	-e "s|@GIT_BUILT_FROM_COMMIT@|$GIT_BUILT_FROM_COMMIT|" \
	-e "s|@GIT_USER_AGENT@|$GIT_USER_AGENT|" \
	-e "s|@GIT_DATE@|$GIT_DATE|" \
	"$INPUT" >"$OUTPUT"+

if ! test -f "$OUTPUT" || ! cmp "$OUTPUT"+ "$OUTPUT" >/dev/null
then
	mv "$OUTPUT"+ "$OUTPUT"
else
	rm "$OUTPUT"+
fi