Re: [gentoo-dev] New eclass: db-use-r1

[Michał Górny]

> # @ECLASS_VARIABLE: DB_VERSIONS
> # @REQUIRED
> # @DESCRIPTION:
> # This variable contains a list of sys-libs/db SLOT versions the package
> # works with. Please always sort the list so that higher slot versions come
> # first or else the package might not depend on the latest possible version of
> # sys-libs/db
> #
> # Example:
> # @CODE
> # DB_VERSIONS=( 5.0 4.8 )
> # inherit db-use-r1
> # @CODE
> #
> # Please note that you can also use bash brace expansion if you like:
> # @CODE
> # DB_VERSIONS=( 5.{3,2,1,0} 4.8 )
> # inherit db-use-r1
> # @CODE
> if ! declare -p DB_VERSIONS &>/dev/null; then
> 	die "DB_VERSIONS not declared."
> fi

You may want to add here an additional check if it is an array. Otherwise,
you may end up with some random behavior when someone sets it to single
string.

> # @ECLASS-VARIABLE: DB_DEPS
> # @DESCRIPTION:
> # This eclass sets and exports DB_DEPS which should be uses as follows:
> #
> # @CODE
> # RDEPEND="${DB_DEPEND}"
> # @CODE

DB_DEPS or DB_DEPEND?

> #
> # or
> #
> # @CODE
> # RDEPEND="berkdb? ( ${DB_DEPEND} )"
> # @CODE
> DB_DEPEND=""
> if [ "${#DB_VERSIONS[@]}" -gt 1 ] ; then
> 	DB_DEPEND="|| ("
> fi

I think it's perfectly valid to have '|| ( single-atom )'. IMO it's not
worth the effort to add it conditionally.

> for db_slotver in ${DB_VERSIONS[@]} ; do
> 	DB_DEPEND+=" sys-libs/db:${db_slotver}"
> done

You can do it without the loop:

DB_DEPEND+=${DB_VERSIONS[@]/#/ sys-libs/db:}

> if [ "${#DB_VERSIONS[@]}" -gt 1 ] ; then
> 	DB_DEPEND+=" )"
> fi
> export DB_DEPEND
> [[ ! -n ${DB_DEPEND} ]] && die "Cannot assing sys-libs/db dependency"

Looks like impossible to me. Well, unless DB_VERSIONS are empty but then
it looks like erring on the result rather than reason.

> inherit versionator multilib
>
> # @FUNCTION: db_ver_to_slot
> # @USAGE: <db-version>
> # @DESCRIPTION:
> # Convert a version to a db slot. You need to submit at least the first two
> # Version components
> # This is meant for ebuilds using the real version number of a sys-libs/db
> # package. This eclass doesn't use it internally.
> db_ver_to_slot() {
> 	if [ $# -ne 1 ]; then
> 		eerror "Function db_ver_to_slot needs one argument" >&2

Shouldn't eerror use stderr on itself?

> 		eerror "args given:" >&2
> 		for f in $@

Missing quoting.

> 		do
> 			eerror " - \"$@\"" >&2
> 		done
> 		return 1
> 	fi
> 	if [ "$(get_version_component_count $1)" -lt 2 ] ; then
> 		eerror "db_ver_to_slot function needs at least a version component"
> 		eerror "count of two."
> 		return 1

'die', please.

> 	fi
> 	echo -n "$(get_version_component_range 1-2 $1)"

Just FYI, '-n' is not really necessary here since shell automatically
strips trailing newline in $().

> }
>
> # @FUNCTION: db_findver
> # @USAGE:
> # @DESCRIPTION:
> # Find the highest installed db version that fits DB_VERSIONS
> db_findver() {
> 	local db_slotver
> 	for db_slotver in ${DB_VERSIONS[@]} ; do
> 		if has_version sys-libs/db:${db_slotver} \
> 			&& [ -d "/usr/include/db${db_slotver}" ] ; then

Why do you need both checks?

> 				echo -n "${db_slotver}"
> 				return 0
> 		fi
> 	done
> 	return 1
> }
>
> # @FUNCTION: db_includedir
> # @USAGE:
> # @DESCRIPTION:
> # Get the include dir for berkeley db. This function returns the best version
> # found by db_findver()
> db_includedir() {
> 	VER="$(db_findver)" || return 1

Shouldn't this be 'local'?

> 	einfo "include version ${VER}" >&2

Looks more like debug-print candidate. Or, at least mention 'berkdb'
somewhere since user will have no idea 'version of what'.

> 	if [ -d "/usr/include/db${VER}" ]; then
> 		echo -n "/usr/include/db${VER}"
> 		return 0
> 	else
> 		eerror "sys-libs/db package requested, but headers not found" >&2
> 		return 1
> 	fi
> }
>
> # @FUNCTION: db_libname
> # @USAGE:
> # @DESCRIPTION:
> # Get the library name for berkeley db. Something like "db-4.2" will be the
> # outcome. This function returns the best version found by db_findver()
> db_libname() {
> 	VER="$(db_findver)" || return 1
> 	if [ -e "/usr/$(get_libdir)/libdb-${VER}.so" ]; then
> 		echo -n "db-${VER}"
> 		return 0
> 	else
> 		eerror "sys-libs/db package requested, but library not found" >&2
> 		return 1
> 	fi
> }

-- 
Best regards,
Michał Górny